Update pool-server.go

Co-authored-by: matst80 <mats.tornberg@gmail.com>
Reviewed-on: https://git.tornberg.me/mats/go-cart-actor/pulls/6
Co-authored-by: Mats Törnberg <mats@tornberg.me>
Co-committed-by: Mats Törnberg <mats@tornberg.me>

.gitea/workflows/build.yaml

@@ -47,10 +47,13 @@ jobs:
           docker push registry.knatofs.se/go-cart-actor-amd64:${{ needs.Metadata.outputs.version }}
       - name: Apply deployment manifests
         run: kubectl apply -f deployment/deployment.yaml -n cart
+      - name: Rollout amd64 backoffice deployment
+        run: |
+          kubectl rollout restart deployment/cart-backoffice-x86 -n cart
       - name: Rollout amd64 deployment (pin to version)
         run: |
           kubectl set image deployment/cart-actor-x86 -n cart cart-actor-amd64=registry.knatofs.se/go-cart-actor-amd64:${{ needs.Metadata.outputs.version }}
-                  kubectl rollout status deployment/cart-actor-x86 -n cart
+          # kubectl rollout status deployment/cart-actor-x86 -n cart
 
   BuildAndDeployArm64:
     needs: Metadata
@@ -74,4 +77,4 @@ jobs:
       - name: Rollout arm64 deployment (pin to version)
         run: |
           kubectl set image deployment/cart-actor-arm64 -n cart cart-actor-arm64=registry.knatofs.se/go-cart-actor:${{ needs.Metadata.outputs.version }}
-                  kubectl rollout status deployment/cart-actor-arm64 -n cart
+          # kubectl rollout status deployment/cart-actor-arm64 -n cart

Dockerfile

@@ -57,7 +57,14 @@ RUN --mount=type=cache,target=/go/build-cache \
     -X main.Version=${VERSION} \
     -X main.GitCommit=${GIT_COMMIT} \
     -X main.BuildDate=${BUILD_DATE}" \
-      -o /out/go-cart-actor .
+    -o /out/go-cart-actor ./cmd/cart
+
+RUN --mount=type=cache,target=/go/build-cache \
+    go build -trimpath -ldflags="-s -w \
+    -X main.Version=${VERSION} \
+    -X main.GitCommit=${GIT_COMMIT} \
+    -X main.BuildDate=${BUILD_DATE}" \
+    -o /out/go-cart-backoffice ./cmd/backoffice
 
 ############################
 # Runtime Stage
@@ -67,6 +74,7 @@ FROM gcr.io/distroless/static-debian12:nonroot AS runtime
 WORKDIR /
 
 COPY --from=build /out/go-cart-actor /go-cart-actor
+COPY --from=build /out/go-cart-backoffice /go-cart-backoffice
 
 # Document (not expose forcibly) typical ports: 8080 (HTTP), 1337 (gRPC)
 EXPOSE 8080 1337

Makefile

@@ -19,7 +19,7 @@
 
 MODULE_PATH := git.tornberg.me/go-cart-actor
 PROTO_DIR   := proto
-PROTOS      := $(PROTO_DIR)/messages.proto $(PROTO_DIR)/cart_actor.proto $(PROTO_DIR)/control_plane.proto
+PROTOS      := $(PROTO_DIR)/messages.proto $(PROTO_DIR)/control_plane.proto
 
 # Allow override: make PROTOC=/path/to/protoc
 PROTOC ?= protoc
@@ -69,8 +69,8 @@ check_tools:
 protogen: check_tools
 	@echo "$(YELLOW)Generating protobuf code (outputs -> ./proto)...$(RESET)"
 	$(PROTOC) -I $(PROTO_DIR) \
-	  --go_out=./proto --go_opt=paths=source_relative \
+	  --go_out=./pkg/messages --go_opt=paths=source_relative \
-	  --go-grpc_out=./proto --go-grpc_opt=paths=source_relative \
+	  --go-grpc_out=./pkg/messages --go-grpc_opt=paths=source_relative \
 	  $(PROTOS)
 	@echo "$(GREEN)Protobuf generation complete.$(RESET)"
 

README.md

@@ -1,36 +1,5 @@
 # Go Cart Actor
 
-## Migration Notes (Ring-based Ownership Transition)
-
-This release removes the legacy ConfirmOwner ownership negotiation RPC in favor of deterministic ownership via the consistent hashing ring.
-
-Summary of changes:
-- ConfirmOwner RPC removed from the ControlPlane service.
-- OwnerChangeRequest message removed (was only used by ConfirmOwner).
-- OwnerChangeAck retained solely as the response type for the Closing RPC.
-- SyncedPool now relies exclusively on the ring for ownership (no quorum negotiation).
-- Remote proxy creation includes a bounded readiness retry to reduce first-call failures.
-- New Prometheus ring metrics: 
-  - cart_ring_epoch
-  - cart_ring_hosts
-  - cart_ring_vnodes
-  - cart_ring_host_share{host}
-  - cart_ring_lookup_local_total
-  - cart_ring_lookup_remote_total
-
-Action required for consumers:
-1. Regenerate protobuf code after pulling (requires protoc-gen-go and protoc-gen-go-grpc installed).
-2. Remove any client code or automation invoking ConfirmOwner (calls will now return UNIMPLEMENTED if using stale generated stubs).
-3. Update monitoring/alerts that referenced ConfirmOwner or ownership quorum failures—use ring metrics instead.
-4. If you previously interpreted “ownership flapping” via ConfirmOwner logs, now check for:
-   - Rapid changes in ring epoch (cart_ring_epoch)
-   - Host churn (cart_ring_hosts)
-   - Imbalance in vnode distribution (cart_ring_host_share)
-
-No data migration is necessary; cart IDs and grain state are unaffected.
-
----
-
 A distributed cart management system using the actor model pattern.
 
 ## Prerequisites

amqp-order-handler.go

@@ -1,61 +0,0 @@
-package main
-
-import (
-	"context"
-	"fmt"
-	"time"
-
-	amqp "github.com/rabbitmq/amqp091-go"
-)
-
-type AmqpOrderHandler struct {
-	Url        string
-	Connection *amqp.Connection
-	Channel    *amqp.Channel
-}
-
-func (h *AmqpOrderHandler) Connect() error {
-	conn, err := amqp.Dial(h.Url)
-	if err != nil {
-		return fmt.Errorf("failed to connect to RabbitMQ: %w", err)
-	}
-	h.Connection = conn
-
-	ch, err := conn.Channel()
-	if err != nil {
-		return fmt.Errorf("failed to open a channel: %w", err)
-	}
-	h.Channel = ch
-
-	return nil
-}
-
-func (h *AmqpOrderHandler) Close() error {
-	if h.Channel != nil {
-		h.Channel.Close()
-	}
-	if h.Connection != nil {
-		return h.Connection.Close()
-	}
-	return nil
-}
-
-func (h *AmqpOrderHandler) OrderCompleted(body []byte) error {
-	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
-	defer cancel()
-
-	err := h.Channel.PublishWithContext(ctx,
-		"orders", // exchange
-		"new",    // routing key
-		false,    // mandatory
-		false,    // immediate
-		amqp.Publishing{
-			ContentType: "application/json",
-			Body:        body,
-		})
-	if err != nil {
-		return fmt.Errorf("failed to publish a message: %w", err)
-	}
-
-	return nil
-}

cart-grain.go

@@ -1,294 +0,0 @@
-package main
-
-import (
-	"encoding/json"
-	"fmt"
-	"sync"
-
-	messages "git.tornberg.me/go-cart-actor/proto"
-)
-
-type CartId [16]byte
-
-// String returns the cart id as a trimmed UTF-8 string (trailing zero bytes removed).
-func (id CartId) String() string {
-	n := 0
-	for n < len(id) && id[n] != 0 {
-		n++
-	}
-	return string(id[:n])
-}
-
-// ToCartId converts an arbitrary string to a fixed-size CartId (truncating or padding with zeros).
-func ToCartId(s string) CartId {
-	var id CartId
-	copy(id[:], []byte(s))
-	return id
-}
-
-func (id CartId) MarshalJSON() ([]byte, error) {
-	return json.Marshal(id.String())
-}
-
-func (id *CartId) UnmarshalJSON(data []byte) error {
-	var str string
-	err := json.Unmarshal(data, &str)
-	if err != nil {
-		return err
-	}
-	copy(id[:], []byte(str))
-	return nil
-}
-
-type StockStatus int
-
-const (
-	OutOfStock StockStatus = 0
-	LowStock   StockStatus = 1
-	InStock    StockStatus = 2
-)
-
-type CartItem struct {
-	Id          int         `json:"id"`
-	ItemId      int         `json:"itemId,omitempty"`
-	ParentId    int         `json:"parentId,omitempty"`
-	Sku         string      `json:"sku"`
-	Name        string      `json:"name"`
-	Price       int64       `json:"price"`
-	TotalPrice  int64       `json:"totalPrice"`
-	TotalTax    int64       `json:"totalTax"`
-	OrgPrice    int64       `json:"orgPrice"`
-	Stock       StockStatus `json:"stock"`
-	Quantity    int         `json:"qty"`
-	Tax         int         `json:"tax"`
-	TaxRate     int         `json:"taxRate"`
-	Brand       string      `json:"brand,omitempty"`
-	Category    string      `json:"category,omitempty"`
-	Category2   string      `json:"category2,omitempty"`
-	Category3   string      `json:"category3,omitempty"`
-	Category4   string      `json:"category4,omitempty"`
-	Category5   string      `json:"category5,omitempty"`
-	Disclaimer  string      `json:"disclaimer,omitempty"`
-	SellerId    string      `json:"sellerId,omitempty"`
-	SellerName  string      `json:"sellerName,omitempty"`
-	ArticleType string      `json:"type,omitempty"`
-	Image       string      `json:"image,omitempty"`
-	Outlet      *string     `json:"outlet,omitempty"`
-	StoreId     *string     `json:"storeId,omitempty"`
-}
-
-type CartDelivery struct {
-	Id          int                   `json:"id"`
-	Provider    string                `json:"provider"`
-	Price       int64                 `json:"price"`
-	Items       []int                 `json:"items"`
-	PickupPoint *messages.PickupPoint `json:"pickupPoint,omitempty"`
-}
-
-type CartGrain struct {
-	mu                sync.RWMutex
-	lastItemId        int
-	lastDeliveryId    int
-	Id                CartId          `json:"id"`
-	Items             []*CartItem     `json:"items"`
-	TotalPrice        int64           `json:"totalPrice"`
-	TotalTax          int64           `json:"totalTax"`
-	TotalDiscount     int64           `json:"totalDiscount"`
-	Deliveries        []*CartDelivery `json:"deliveries,omitempty"`
-	Processing        bool            `json:"processing"`
-	PaymentInProgress bool            `json:"paymentInProgress"`
-	OrderReference    string          `json:"orderReference,omitempty"`
-	PaymentStatus     string          `json:"paymentStatus,omitempty"`
-}
-
-type Grain interface {
-	GetId() CartId
-	Apply(content interface{}, isReplay bool) (*CartGrain, error)
-	GetCurrentState() (*CartGrain, error)
-}
-
-func (c *CartGrain) GetId() CartId {
-	return c.Id
-}
-
-func (c *CartGrain) GetLastChange() int64 {
-	// Legacy event log removed; return 0 to indicate no persisted mutation history.
-	return 0
-}
-
-func (c *CartGrain) GetCurrentState() (*CartGrain, error) {
-	return c, nil
-}
-
-func getInt(data float64, ok bool) (int, error) {
-	if !ok {
-		return 0, fmt.Errorf("invalid type")
-	}
-	return int(data), nil
-}
-
-func getItemData(sku string, qty int, country string) (*messages.AddItem, error) {
-	item, err := FetchItem(sku, country)
-	if err != nil {
-		return nil, err
-	}
-	orgPrice, _ := getInt(item.GetNumberFieldValue(5)) // getInt(item.Fields[5])
-
-	price, priceErr := getInt(item.GetNumberFieldValue(4)) //Fields[4]
-
-	if priceErr != nil {
-		return nil, fmt.Errorf("invalid price")
-	}
-
-	stock := InStock
-	/*item.t
-	if item.StockLevel == "0" || item.StockLevel == "" {
-		stock = OutOfStock
-	} else if item.StockLevel == "5+" {
-		stock = LowStock
-		}*/
-	articleType, _ := item.GetStringFieldValue(1)   //.Fields[1].(string)
-	outletGrade, ok := item.GetStringFieldValue(20) //.Fields[20].(string)
-	var outlet *string
-	if ok {
-		outlet = &outletGrade
-	}
-	sellerId, _ := item.GetStringFieldValue(24)  // .Fields[24].(string)
-	sellerName, _ := item.GetStringFieldValue(9) // .Fields[9].(string)
-
-	brand, _ := item.GetStringFieldValue(2)      //.Fields[2].(string)
-	category, _ := item.GetStringFieldValue(10)  //.Fields[10].(string)
-	category2, _ := item.GetStringFieldValue(11) //.Fields[11].(string)
-	category3, _ := item.GetStringFieldValue(12) //.Fields[12].(string)
-	category4, _ := item.GetStringFieldValue(13) //Fields[13].(string)
-	category5, _ := item.GetStringFieldValue(14) //.Fields[14].(string)
-
-	return &messages.AddItem{
-		ItemId:      int64(item.Id),
-		Quantity:    int32(qty),
-		Price:       int64(price),
-		OrgPrice:    int64(orgPrice),
-		Sku:         sku,
-		Name:        item.Title,
-		Image:       item.Img,
-		Stock:       int32(stock),
-		Brand:       brand,
-		Category:    category,
-		Category2:   category2,
-		Category3:   category3,
-		Category4:   category4,
-		Category5:   category5,
-		Tax:         2500,
-		SellerId:    sellerId,
-		SellerName:  sellerName,
-		ArticleType: articleType,
-		Disclaimer:  item.Disclaimer,
-		Country:     country,
-		Outlet:      outlet,
-	}, nil
-}
-
-func (c *CartGrain) AddItem(sku string, qty int, country string, storeId *string) (*CartGrain, error) {
-	cartItem, err := getItemData(sku, qty, country)
-	if err != nil {
-		return nil, err
-	}
-	cartItem.StoreId = storeId
-	return c.Apply(cartItem, false)
-}
-
-/*
-Legacy storage (event sourcing) removed in oneof refactor.
-Kept stub (commented) for potential future reintroduction using proto envelopes.
-
-func (c *CartGrain) GetStorageMessage(since int64) []interface{} {
-	return nil
-}
-*/
-
-func (c *CartGrain) GetState() ([]byte, error) {
-	return json.Marshal(c)
-}
-
-func (c *CartGrain) ItemsWithDelivery() []int {
-	ret := make([]int, 0, len(c.Items))
-	for _, item := range c.Items {
-		for _, delivery := range c.Deliveries {
-			for _, id := range delivery.Items {
-				if item.Id == id {
-					ret = append(ret, id)
-				}
-			}
-		}
-	}
-	return ret
-}
-
-func (c *CartGrain) ItemsWithoutDelivery() []int {
-	ret := make([]int, 0, len(c.Items))
-	hasDelivery := c.ItemsWithDelivery()
-	for _, item := range c.Items {
-		found := false
-		for _, id := range hasDelivery {
-			if item.Id == id {
-				found = true
-				break
-			}
-		}
-
-		if !found {
-			ret = append(ret, item.Id)
-		}
-	}
-	return ret
-}
-
-func (c *CartGrain) FindItemWithSku(sku string) (*CartItem, bool) {
-	c.mu.RLock()
-	defer c.mu.RUnlock()
-	for _, item := range c.Items {
-		if item.Sku == sku {
-			return item, true
-		}
-	}
-	return nil, false
-}
-
-func GetTaxAmount(total int64, tax int) int64 {
-	taxD := 10000 / float64(tax)
-	return int64(float64(total) / float64((1 + taxD)))
-}
-
-func (c *CartGrain) Apply(content interface{}, isReplay bool) (*CartGrain, error) {
-	grainMutations.Inc()
-
-	updated, err := ApplyRegistered(c, content)
-	if err != nil {
-		if err == ErrMutationNotRegistered {
-			return nil, fmt.Errorf("unsupported mutation type %T (not registered)", content)
-		}
-		return nil, err
-	}
-	return updated, nil
-}
-
-func (c *CartGrain) UpdateTotals() {
-	c.TotalPrice = 0
-	c.TotalTax = 0
-	c.TotalDiscount = 0
-	for _, item := range c.Items {
-		rowTotal := item.Price * int64(item.Quantity)
-		rowTax := int64(item.Tax) * int64(item.Quantity)
-		item.TotalPrice = rowTotal
-		item.TotalTax = rowTax
-		c.TotalPrice += rowTotal
-		c.TotalTax += rowTax
-		itemDiff := max(0, item.OrgPrice-item.Price)
-		c.TotalDiscount += itemDiff * int64(item.Quantity)
-	}
-	for _, delivery := range c.Deliveries {
-		c.TotalPrice += delivery.Price
-		c.TotalTax += GetTaxAmount(delivery.Price, 2500)
-	}
-
-}

cart_id.go

@@ -1,327 +0,0 @@
-package main
-
-import (
-	"crypto/rand"
-	"encoding/binary"
-	"errors"
-	"fmt"
-	"strings"
-)
-
-// cart_id.go
-//
-// Compact CartID implementation using 64 bits of cryptographic randomness,
-// base62 encoded (0-9 A-Z a-z). Typical length is 11 characters (since 62^11 > 2^64).
-//
-// Motivation:
-//   * Shorter identifiers for cookies / URLs than legacy padded 16-byte CartId
-//   * O(1) hashing (raw uint64) for consistent hashing ring integration
-//   * Extremely low collision probability (birthday bound negligible at scale)
-//
-// Backward Compatibility Strategy (Phased):
-//   Phase 1: Introduce CartID helpers while continuing to accept legacy CartId.
-//   Phase 2: Internally migrate maps to key by uint64 (CartID.Raw()).
-//   Phase 3: Canonicalize all inbound IDs to short base62; reissue Set-Cart-Id header.
-//
-// NOTE:
-//   The legacy type `CartId [16]byte` is still present elsewhere; helper
-//   UpgradeLegacyCartId bridges that representation to the new form without
-//   breaking deterministic mapping for existing carts.
-//
-// Security / Predictability:
-//   Uses crypto/rand for generation. If ever required, you can layer an
-//   HMAC-based derivation for additional secrecy. Current approach already
-//   provides 64 bits of entropy (brute force infeasible for practical risk).
-//
-// Future Extensions:
-//   * Time-sortable IDs: prepend a 48-bit timestamp field and encode 80 bits.
-//   * Add metrics counters for: generated_new, parsed_existing, legacy_fallback.
-//   * Add a pool of pre-generated IDs for ultra-low-latency hot paths (rarely needed).
-//
-// Public Surface Summary:
-//   NewCartID() (CartID, error)
-//   ParseCartID(string) (CartID, bool)
-//   FallbackFromString(string) CartID
-//   UpgradeLegacyCartId(CartId) CartID
-//   CanonicalizeIncoming(string) (CartID, bool /*wasGenerated*/, error)
-//
-// Encoding Details:
-//   encodeBase62 / decodeBase62 maintain a stable alphabet. DO NOT change
-//   alphabet order once IDs are in circulation, or previously issued IDs
-//   will change meaning.
-//
-// Zero Values:
-//   The zero value CartID{} has raw=0, txt="0". Treat it as valid but
-//   usually you will call NewCartID instead.
-//
-// ---------------------------------------------------------------------------
-
-const base62Alphabet = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"
-
-// Precomputed reverse lookup table for decode (255 = invalid).
-var base62Rev [256]byte
-
-func init() {
-	for i := range base62Rev {
-		base62Rev[i] = 0xFF
-	}
-	for i := 0; i < len(base62Alphabet); i++ {
-		base62Rev[base62Alphabet[i]] = byte(i)
-	}
-}
-
-// CartID is the compact representation of a cart identifier.
-// raw: 64-bit entropy (also used directly for consistent hashing).
-// txt: cached base62 textual form.
-type CartID struct {
-	raw uint64
-	txt string
-}
-
-// String returns the canonical base62 encoded ID.
-func (c CartID) String() string {
-	if c.txt == "" { // lazily encode if constructed manually
-		c.txt = encodeBase62(c.raw)
-	}
-	return c.txt
-}
-
-// Raw returns the 64-bit numeric value (useful for hashing / ring lookup).
-func (c CartID) Raw() uint64 {
-	return c.raw
-}
-
-// IsZero reports whether this CartID is the zero value.
-func (c CartID) IsZero() bool {
-	return c.raw == 0
-}
-
-// NewCartID generates a new cryptographically random 64-bit ID.
-func NewCartID() (CartID, error) {
-	var b [8]byte
-	if _, err := rand.Read(b[:]); err != nil {
-		return CartID{}, fmt.Errorf("NewCartID: %w", err)
-	}
-	u := binary.BigEndian.Uint64(b[:])
-	// Reject zero if you want to avoid ever producing "0" (optional).
-	if u == 0 {
-		// Extremely unlikely; recurse once.
-		return NewCartID()
-	}
-	return CartID{raw: u, txt: encodeBase62(u)}, nil
-}
-
-// MustNewCartID panics on failure (suitable for tests / initialization).
-func MustNewCartID() CartID {
-	id, err := NewCartID()
-	if err != nil {
-		panic(err)
-	}
-	return id
-}
-
-// ParseCartID attempts to parse a base62 canonical ID.
-// Returns (id, true) if fully valid; (zero, false) otherwise.
-func ParseCartID(s string) (CartID, bool) {
-	if len(s) == 0 {
-		return CartID{}, false
-	}
-	// Basic length sanity; allow a bit of headroom for future timestamp variant.
-	if len(s) > 16 {
-		return CartID{}, false
-	}
-	u, ok := decodeBase62(s)
-	if !ok {
-		return CartID{}, false
-	}
-	return CartID{raw: u, txt: s}, true
-}
-
-// FallbackFromString produces a deterministic CartID from arbitrary input
-// using a 64-bit FNV-1a hash. This allows legacy or malformed IDs to map
-// consistently into the new scheme (collision probability still low).
-func FallbackFromString(s string) CartID {
-	const (
-		offset64 = 1469598103934665603
-		prime64  = 1099511628211
-	)
-	h := uint64(offset64)
-	for i := 0; i < len(s); i++ {
-		h ^= uint64(s[i])
-		h *= prime64
-	}
-	return CartID{raw: h, txt: encodeBase62(h)}
-}
-
-// UpgradeLegacyCartId converts the old 16-byte CartId (padded) to CartID
-// by hashing its trimmed string form. Keeps stable mapping across restarts.
-func UpgradeLegacyCartId(old CartId) CartID {
-	return FallbackFromString(old.String())
-}
-
-// CanonicalizeIncoming normalizes user-provided ID strings.
-// Behavior:
-//
-//	Empty string  -> generate new ID (wasGenerated = true)
-//	Valid base62  -> parse and return (wasGenerated = false)
-//	Anything else -> fallback deterministic hash (wasGenerated = false)
-//
-// Errors only occur if crypto/rand fails during generation.
-func CanonicalizeIncoming(s string) (CartID, bool, error) {
-	if s == "" {
-		id, err := NewCartID()
-		return id, true, err
-	}
-	if cid, ok := ParseCartID(s); ok {
-		return cid, false, nil
-	}
-	// Legacy heuristic: if length == 16 and contains non-base62 chars, treat as legacy padded ID.
-	if len(s) == 16 && !isAllBase62(s) {
-		return FallbackFromString(strings.TrimRight(s, "\x00")), false, nil
-	}
-	return FallbackFromString(s), false, nil
-}
-
-// isAllBase62 returns true if every byte is in the base62 alphabet.
-func isAllBase62(s string) bool {
-	for i := 0; i < len(s); i++ {
-		if base62Rev[s[i]] == 0xFF {
-			return false
-		}
-	}
-	return true
-}
-
-// encodeBase62 turns a uint64 into base62 text.
-// Complexity: O(log_62 n) ~ at most 11 iterations for 64 bits.
-func encodeBase62(u uint64) string {
-	if u == 0 {
-		return "0"
-	}
-	// 62^11 = 743008370688 > 2^39; 62^11 > 2^64? Actually 62^11 ~= 5.18e19 < 2^64 (1.84e19)? 2^64 ≈ 1.84e19.
-	// 62^11 ≈ 5.18e19 > 2^64? Correction: 2^64 ≈ 1.844e19, so 62^11 > 2^64. Thus 11 chars suffice.
-	var buf [11]byte
-	i := len(buf)
-	for u > 0 {
-		i--
-		buf[i] = base62Alphabet[u%62]
-		u /= 62
-	}
-	return string(buf[i:])
-}
-
-// decodeBase62 converts a base62 string to uint64.
-// Returns (value, false) if any invalid character appears.
-func decodeBase62(s string) (uint64, bool) {
-	var v uint64
-	for i := 0; i < len(s); i++ {
-		c := s[i]
-		d := base62Rev[c]
-		if d == 0xFF {
-			return 0, false
-		}
-		v = v*62 + uint64(d)
-	}
-	return v, true
-}
-
-// ErrInvalidCartID can be returned by higher-level validation layers if you decide
-// to reject fallback-derived IDs (currently unused here).
-var ErrInvalidCartID = errors.New("invalid cart id")
-
-// ---------------------------------------------------------------------------
-// Legacy / Compatibility Conversion Helpers
-// ---------------------------------------------------------------------------
-
-// CartIDToLegacy converts a CartID (base62) into the legacy fixed-size CartId
-// ([16]byte) by copying the textual form (truncated or zero-padded).
-// NOTE: If the base62 string is longer than 16 (should not happen with current
-// 64-bit space), it will be truncated.
-func CartIDToLegacy(c CartID) CartId {
-	var id CartId
-	txt := c.String()
-	copy(id[:], []byte(txt))
-	return id
-}
-
-// LegacyToCartID upgrades a legacy CartId (padded) to a CartID by hashing its
-// trimmed string form (deterministic). This preserves stable mapping without
-// depending on original randomness.
-func LegacyToCartID(old CartId) CartID {
-	return UpgradeLegacyCartId(old)
-}
-
-// CartIDToKey returns the numeric key representation (uint64) for map indexing.
-func CartIDToKey(c CartID) uint64 {
-	return c.Raw()
-}
-
-// LegacyToCartKey converts a legacy CartId to the numeric key via deterministic
-// fallback hashing. (Uses the same logic as LegacyToCartID then returns raw.)
-func LegacyToCartKey(old CartId) uint64 {
-	return LegacyToCartID(old).Raw()
-}
-
-// ---------------------- Optional Helper Utilities ----------------------------
-
-// CartIDOrNew tries to parse s; if empty OR invalid returns a fresh ID.
-func CartIDOrNew(s string) (CartID, bool /*wasParsed*/, error) {
-	if cid, ok := ParseCartID(s); ok {
-		return cid, true, nil
-	}
-	id, err := NewCartID()
-	return id, false, err
-}
-
-// MustParseCartID panics if s is not a valid base62 ID (useful in tests).
-func MustParseCartID(s string) CartID {
-	if cid, ok := ParseCartID(s); ok {
-		return cid
-	}
-	panic(fmt.Sprintf("invalid CartID: %s", s))
-}
-
-// DebugString returns a verbose description (for logging / diagnostics).
-func (c CartID) DebugString() string {
-	return fmt.Sprintf("CartID(raw=%d txt=%s)", c.raw, c.String())
-}
-
-// Equal compares two CartIDs by raw value.
-func (c CartID) Equal(other CartID) bool {
-	return c.raw == other.raw
-}
-
-// CanonicalizeOrLegacy preserves legacy (non-base62) IDs without altering their
-// textual form, avoiding the previous behavior where fallback hashing replaced
-// the original string with a base62-encoded hash (which broke deterministic
-// key derivation across mixed call paths).
-//
-// Behavior:
-//   - s == ""      -> generate new CartID (generatedNew = true, wasBase62 = true)
-//   - base62 ok    -> return parsed CartID (generatedNew = false, wasBase62 = true)
-//   - otherwise    -> treat as legacy: raw = hash(s), txt = original s
-//
-// Returns:
-//
-//	cid          - CartID (txt preserved for legacy inputs)
-//	generatedNew - true only when a brand new ID was created due to empty input
-//	wasBase62    - true if the input was already canonical base62 (or generated)
-//	err          - only set if crypto/rand fails when generating a new ID
-func CanonicalizeOrLegacy(s string) (cid CartID, generatedNew bool, wasBase62 bool, err error) {
-	if s == "" {
-		id, e := NewCartID()
-		if e != nil {
-			return CartID{}, false, false, e
-		}
-		return id, true, true, nil
-	}
-	if parsed, ok := ParseCartID(s); ok {
-		return parsed, false, true, nil
-	}
-	// Legacy path: keep original text so downstream legacy-to-key hashing
-	// (which uses the visible string) yields consistent keys across code paths.
-	hashCID := FallbackFromString(s)
-	// Preserve original textual form
-	hashCID.txt = s
-	return hashCID, false, false, nil
-}

cart_id_test.go

@@ -1,259 +0,0 @@
-package main
-
-import (
-	"crypto/rand"
-	"encoding/binary"
-	"fmt"
-	mrand "math/rand"
-	"testing"
-)
-
-// TestEncodeDecodeBase62RoundTrip verifies encodeBase62/decodeBase62 are inverse.
-func TestEncodeDecodeBase62RoundTrip(t *testing.T) {
-	mrand.Seed(42)
-	for i := 0; i < 1000; i++ {
-		// Random 64-bit value
-		v := mrand.Uint64()
-		s := encodeBase62(v)
-		dec, ok := decodeBase62(s)
-		if !ok {
-			t.Fatalf("decodeBase62 failed for %d encoded=%s", v, s)
-		}
-		if dec != v {
-			t.Fatalf("round trip mismatch: have %d got %d (encoded=%s)", v, dec, s)
-		}
-	}
-	// Explicit zero test
-	if s := encodeBase62(0); s != "0" {
-		t.Fatalf("expected encodeBase62(0) == \"0\", got %q", s)
-	}
-	if v, ok := decodeBase62("0"); !ok || v != 0 {
-		t.Fatalf("decodeBase62(0) unexpected result v=%d ok=%v", v, ok)
-	}
-}
-
-// TestNewCartIDUniqueness generates a number of IDs and checks for duplicates.
-func TestNewCartIDUniqueness(t *testing.T) {
-	const n = 10000
-	seen := make(map[string]struct{}, n)
-	for i := 0; i < n; i++ {
-		id, err := NewCartID()
-		if err != nil {
-			t.Fatalf("NewCartID error: %v", err)
-		}
-		s := id.String()
-		if _, exists := seen[s]; exists {
-			t.Fatalf("duplicate CartID generated: %s", s)
-		}
-		seen[s] = struct{}{}
-		if id.IsZero() {
-			t.Fatalf("NewCartID returned zero value")
-		}
-	}
-}
-
-// TestParseCartIDValidation tests parsing of valid and invalid base62 strings.
-func TestParseCartIDValidation(t *testing.T) {
-	id, err := NewCartID()
-	if err != nil {
-		t.Fatalf("NewCartID error: %v", err)
-	}
-	parsed, ok := ParseCartID(id.String())
-	if !ok {
-		t.Fatalf("ParseCartID failed for valid id %s", id)
-	}
-	if parsed.raw != id.raw {
-		t.Fatalf("parsed raw mismatch: %d vs %d", parsed.raw, id.raw)
-	}
-
-	if _, ok := ParseCartID(""); ok {
-		t.Fatalf("expected empty string to be invalid")
-	}
-	// Invalid char ('-')
-	if _, ok := ParseCartID("abc-123"); ok {
-		t.Fatalf("expected invalid chars to fail parse")
-	}
-	// Overly long ( >16 )
-	if _, ok := ParseCartID("1234567890abcdefg"); ok {
-		t.Fatalf("expected overly long string to fail parse")
-	}
-}
-
-// TestFallbackDeterminism ensures fallback hashing is deterministic.
-func TestFallbackDeterminism(t *testing.T) {
-	inputs := []string{
-		"legacy-cart-1",
-		"legacy-cart-2",
-		"UPPER_lower_123",
-		"🚀unicode", // unicode bytes (will hash byte sequence)
-	}
-	for _, in := range inputs {
-		a := FallbackFromString(in)
-		b := FallbackFromString(in)
-		if a.raw != b.raw || a.String() != b.String() {
-			t.Fatalf("fallback mismatch for %q: %+v vs %+v", in, a, b)
-		}
-	}
-	// Distinct inputs should almost always differ; sample check
-	a := FallbackFromString("distinct-A")
-	b := FallbackFromString("distinct-B")
-	if a.raw == b.raw {
-		t.Fatalf("unexpected identical fallback hashes for distinct inputs")
-	}
-}
-
-// TestCanonicalizeIncomingBehavior covers main control flow branches.
-func TestCanonicalizeIncomingBehavior(t *testing.T) {
-	// Empty => new id
-	id1, generated, err := CanonicalizeIncoming("")
-	if err != nil || !generated || id1.IsZero() {
-		t.Fatalf("CanonicalizeIncoming empty failed: id=%v gen=%v err=%v", id1, generated, err)
-	}
-
-	// Valid base62 => parse; no generation
-	id2, gen2, err := CanonicalizeIncoming(id1.String())
-	if err != nil || gen2 || id2.raw != id1.raw {
-		t.Fatalf("CanonicalizeIncoming parse mismatch: id2=%v gen2=%v err=%v", id2, gen2, err)
-	}
-
-	// Legacy-like random containing invalid chars -> fallback
-	fallbackInput := "legacy\x00\x00padding"
-	id3, gen3, err := CanonicalizeIncoming(fallbackInput)
-	if err != nil || gen3 {
-		t.Fatalf("CanonicalizeIncoming fallback unexpected: id3=%v gen3=%v err=%v", id3, gen3, err)
-	}
-
-	// Deterministic fallback
-	id4, _, _ := CanonicalizeIncoming(fallbackInput)
-	if id3.raw != id4.raw {
-		t.Fatalf("fallback canonicalization not deterministic")
-	}
-}
-
-// TestUpgradeLegacyCartId ensures mapping of old CartId is stable.
-func TestUpgradeLegacyCartId(t *testing.T) {
-	var legacy CartId
-	copy(legacy[:], []byte("legacy-123456789")) // 15 bytes + padding
-	up1 := UpgradeLegacyCartId(legacy)
-	up2 := UpgradeLegacyCartId(legacy)
-	if up1.raw != up2.raw {
-		t.Fatalf("UpgradeLegacyCartId not deterministic: %v vs %v", up1, up2)
-	}
-	if up1.String() != up2.String() {
-		t.Fatalf("UpgradeLegacyCartId string mismatch: %s vs %s", up1, up2)
-	}
-}
-
-// BenchmarkNewCartID gives a rough idea of generation cost.
-func BenchmarkNewCartID(b *testing.B) {
-	for i := 0; i < b.N; i++ {
-		if _, err := NewCartID(); err != nil {
-			b.Fatalf("error: %v", err)
-		}
-	}
-}
-
-// BenchmarkEncodeBase62 measures encode speed in isolation.
-func BenchmarkEncodeBase62(b *testing.B) {
-	// Random sample of values
-	samples := make([]uint64, 1024)
-	for i := range samples {
-		var buf [8]byte
-		if _, err := rand.Read(buf[:]); err != nil {
-			b.Fatalf("rand: %v", err)
-		}
-		samples[i] = binary.BigEndian.Uint64(buf[:])
-	}
-	b.ResetTimer()
-	var sink string
-	for i := 0; i < b.N; i++ {
-		sink = encodeBase62(samples[i%len(samples)])
-	}
-	_ = sink
-}
-
-// BenchmarkDecodeBase62 measures decode speed.
-func BenchmarkDecodeBase62(b *testing.B) {
-	// Pre-encode
-	encoded := make([]string, 1024)
-	for i := range encoded {
-		encoded[i] = encodeBase62(uint64(i)<<32 | uint64(i))
-	}
-	b.ResetTimer()
-	var sum uint64
-	for i := 0; i < b.N; i++ {
-		v, ok := decodeBase62(encoded[i%len(encoded)])
-		if !ok {
-			b.Fatalf("decode failed")
-		}
-		sum ^= v
-	}
-	_ = sum
-}
-
-// TestLookupNDeterminism (ring integration smoke test) ensures LookupN
-// returns distinct hosts and stable ordering for a fixed ring.
-func TestLookupNDeterminism(t *testing.T) {
-	rb := NewRingBuilder().WithEpoch(1).WithVnodesPerHost(8).WithHosts([]string{"a", "b", "c"})
-	ring := rb.Build()
-	if ring.Empty() {
-		t.Fatalf("expected non-empty ring")
-	}
-	id := MustNewCartID()
-	owners1 := ring.LookupN(id.Raw(), 3)
-	owners2 := ring.LookupN(id.Raw(), 3)
-	if len(owners1) != len(owners2) {
-		t.Fatalf("LookupN length mismatch")
-	}
-	for i := range owners1 {
-		if owners1[i].Host != owners2[i].Host {
-			t.Fatalf("LookupN ordering instability at %d: %v vs %v", i, owners1[i], owners2[i])
-		}
-	}
-	// Distinct host constraint
-	seen := map[string]struct{}{}
-	for _, v := range owners1 {
-		if _, ok := seen[v.Host]; ok {
-			t.Fatalf("duplicate host in LookupN result: %v", owners1)
-		}
-		seen[v.Host] = struct{}{}
-	}
-}
-
-// TestRingFingerprintChanges ensures fingerprint updates with membership changes.
-func TestRingFingerprintChanges(t *testing.T) {
-	b1 := NewRingBuilder().WithEpoch(1).WithHosts([]string{"node1", "node2"})
-	r1 := b1.Build()
-	b2 := NewRingBuilder().WithEpoch(2).WithHosts([]string{"node1", "node2", "node3"})
-	r2 := b2.Build()
-	if r1.Fingerprint() == r2.Fingerprint() {
-		t.Fatalf("expected differing fingerprints after host set change")
-	}
-}
-
-// TestRingDiffHosts verifies added/removed host detection.
-func TestRingDiffHosts(t *testing.T) {
-	r1 := NewRingBuilder().WithEpoch(1).WithHosts([]string{"a", "b"}).Build()
-	r2 := NewRingBuilder().WithEpoch(2).WithHosts([]string{"b", "c"}).Build()
-	added, removed := r1.DiffHosts(r2)
-	if fmt.Sprintf("%v", added) != "[c]" {
-		t.Fatalf("expected added [c], got %v", added)
-	}
-	if fmt.Sprintf("%v", removed) != "[a]" {
-		t.Fatalf("expected removed [a], got %v", removed)
-	}
-}
-
-// TestRingLookupConsistency ensures direct Lookup and LookupID are aligned.
-func TestRingLookupConsistency(t *testing.T) {
-	ring := NewRingBuilder().WithEpoch(1).WithHosts([]string{"alpha", "beta"}).WithVnodesPerHost(4).Build()
-	id, _ := ParseCartID("1")
-	if id.IsZero() {
-		t.Fatalf("expected parsed id non-zero")
-	}
-	v1 := ring.Lookup(id.Raw())
-	v2 := ring.LookupID(id)
-	if v1.Host != v2.Host || v1.Hash != v2.Hash {
-		t.Fatalf("Lookup vs LookupID mismatch: %+v vs %+v", v1, v2)
-	}
-}

cart_state_mapper.go

@@ -1,212 +0,0 @@
-package main
-
-import (
-	messages "git.tornberg.me/go-cart-actor/proto"
-)
-
-// cart_state_mapper.go
-//
-// Utilities to translate between internal CartGrain state and the gRPC
-// (typed) protobuf representation CartState. This replaces the previous
-// JSON blob framing and enables type-safe replies over gRPC, as well as
-// internal reuse for HTTP handlers without an extra marshal / unmarshal
-// hop (you can marshal CartState directly for JSON responses if desired).
-//
-// Only the one‑way mapping (CartGrain -> CartState) is strictly required
-// for mutation / state replies. A reverse helper is included in case
-// future features (e.g. snapshot import, replay, or migration) need it.
-
-// ToCartState converts the in‑memory CartGrain into a protobuf CartState.
-func ToCartState(c *CartGrain) *messages.CartState {
-	if c == nil {
-		return nil
-	}
-
-	items := make([]*messages.CartItemState, 0, len(c.Items))
-	for _, it := range c.Items {
-		if it == nil {
-			continue
-		}
-		itemDiscountPerUnit := max(0, it.OrgPrice-it.Price)
-		itemTotalDiscount := itemDiscountPerUnit * int64(it.Quantity)
-
-		items = append(items, &messages.CartItemState{
-			Id:            int64(it.Id),
-			ItemId:        int64(it.ItemId),
-			Sku:           it.Sku,
-			Name:          it.Name,
-			Price:         it.Price,
-			Qty:           int32(it.Quantity),
-			TotalPrice:    it.TotalPrice,
-			TotalTax:      it.TotalTax,
-			OrgPrice:      it.OrgPrice,
-			TaxRate:       int32(it.TaxRate),
-			TotalDiscount: itemTotalDiscount,
-			Brand:         it.Brand,
-			Category:      it.Category,
-			Category2:     it.Category2,
-			Category3:     it.Category3,
-			Category4:     it.Category4,
-			Category5:     it.Category5,
-			Image:         it.Image,
-			Type:          it.ArticleType,
-			SellerId:      it.SellerId,
-			SellerName:    it.SellerName,
-			Disclaimer:    it.Disclaimer,
-			Outlet:        deref(it.Outlet),
-			StoreId:       deref(it.StoreId),
-			Stock:         int32(it.Stock),
-		})
-	}
-
-	deliveries := make([]*messages.DeliveryState, 0, len(c.Deliveries))
-	for _, d := range c.Deliveries {
-		if d == nil {
-			continue
-		}
-		itemIds := make([]int64, 0, len(d.Items))
-		for _, id := range d.Items {
-			itemIds = append(itemIds, int64(id))
-		}
-		var pp *messages.PickupPoint
-		if d.PickupPoint != nil {
-			// Copy to avoid accidental shared mutation (proto points are fine but explicit).
-			pp = &messages.PickupPoint{
-				Id:      d.PickupPoint.Id,
-				Name:    d.PickupPoint.Name,
-				Address: d.PickupPoint.Address,
-				City:    d.PickupPoint.City,
-				Zip:     d.PickupPoint.Zip,
-				Country: d.PickupPoint.Country,
-			}
-		}
-		deliveries = append(deliveries, &messages.DeliveryState{
-			Id:          int64(d.Id),
-			Provider:    d.Provider,
-			Price:       d.Price,
-			Items:       itemIds,
-			PickupPoint: pp,
-		})
-	}
-
-	return &messages.CartState{
-		Id:                c.Id.String(),
-		Items:             items,
-		TotalPrice:        c.TotalPrice,
-		TotalTax:          c.TotalTax,
-		TotalDiscount:     c.TotalDiscount,
-		Deliveries:        deliveries,
-		PaymentInProgress: c.PaymentInProgress,
-		OrderReference:    c.OrderReference,
-		PaymentStatus:     c.PaymentStatus,
-	}
-}
-
-// FromCartState merges a protobuf CartState into an existing CartGrain.
-// This is optional and primarily useful for snapshot import or testing.
-func FromCartState(cs *messages.CartState, g *CartGrain) *CartGrain {
-	if cs == nil {
-		return g
-	}
-	if g == nil {
-		g = &CartGrain{}
-	}
-	g.Id = ToCartId(cs.Id)
-	g.TotalPrice = cs.TotalPrice
-	g.TotalTax = cs.TotalTax
-	g.TotalDiscount = cs.TotalDiscount
-	g.PaymentInProgress = cs.PaymentInProgress
-	g.OrderReference = cs.OrderReference
-	g.PaymentStatus = cs.PaymentStatus
-
-	// Items
-	g.Items = g.Items[:0]
-	for _, it := range cs.Items {
-		if it == nil {
-			continue
-		}
-		outlet := toPtr(it.Outlet)
-		storeId := toPtr(it.StoreId)
-		g.Items = append(g.Items, &CartItem{
-			Id:          int(it.Id),
-			ItemId:      int(it.ItemId),
-			Sku:         it.Sku,
-			Name:        it.Name,
-			Price:       it.Price,
-			Quantity:    int(it.Qty),
-			TotalPrice:  it.TotalPrice,
-			TotalTax:    it.TotalTax,
-			OrgPrice:    it.OrgPrice,
-			TaxRate:     int(it.TaxRate),
-			Brand:       it.Brand,
-			Category:    it.Category,
-			Category2:   it.Category2,
-			Category3:   it.Category3,
-			Category4:   it.Category4,
-			Category5:   it.Category5,
-			Image:       it.Image,
-			ArticleType: it.Type,
-			SellerId:    it.SellerId,
-			SellerName:  it.SellerName,
-			Disclaimer:  it.Disclaimer,
-			Outlet:      outlet,
-			StoreId:     storeId,
-			Stock:       StockStatus(it.Stock),
-			// Tax, TaxRate already set via Price / Totals if needed
-		})
-		if it.Id > int64(g.lastItemId) {
-			g.lastItemId = int(it.Id)
-		}
-	}
-
-	// Deliveries
-	g.Deliveries = g.Deliveries[:0]
-	for _, d := range cs.Deliveries {
-		if d == nil {
-			continue
-		}
-
-		intIds := make([]int, 0, len(d.Items))
-		for _, id := range d.Items {
-			intIds = append(intIds, int(id))
-		}
-		var pp *messages.PickupPoint
-		if d.PickupPoint != nil {
-			pp = &messages.PickupPoint{
-				Id:      d.PickupPoint.Id,
-				Name:    d.PickupPoint.Name,
-				Address: d.PickupPoint.Address,
-				City:    d.PickupPoint.City,
-				Zip:     d.PickupPoint.Zip,
-				Country: d.PickupPoint.Country,
-			}
-		}
-		g.Deliveries = append(g.Deliveries, &CartDelivery{
-			Id:          int(d.Id),
-			Provider:    d.Provider,
-			Price:       d.Price,
-			Items:       intIds,
-			PickupPoint: pp,
-		})
-		if d.Id > int64(g.lastDeliveryId) {
-			g.lastDeliveryId = int(d.Id)
-		}
-	}
-
-	return g
-}
-
-// Helper to safely de-reference optional string pointers to value or "".
-func deref(p *string) string {
-	if p == nil {
-		return ""
-	}
-	return *p
-}
-
-func toPtr(s string) *string {
-	if s == "" {
-		return nil
-	}
-	return &s
-}

cmd/backoffice/fileserver.go

@@ -0,0 +1,280 @@
+package main
+
+import (
+	"bufio"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io"
+	"io/fs"
+	"net/http"
+	"os"
+	"path/filepath"
+	"sort"
+	"strconv"
+	"strings"
+	"time"
+
+	"git.tornberg.me/go-cart-actor/pkg/actor"
+	"git.tornberg.me/go-cart-actor/pkg/cart"
+)
+
+type FileServer struct {
+	// Define fields here
+	dataDir string
+	storage actor.LogStorage[cart.CartGrain]
+}
+
+func NewFileServer(dataDir string, storage actor.LogStorage[cart.CartGrain]) *FileServer {
+	return &FileServer{
+		dataDir: dataDir,
+		storage: storage,
+	}
+}
+
+func isValidId(id string) (uint64, bool) {
+	if nr, err := strconv.ParseUint(id, 10, 64); err == nil {
+		return nr, true
+	}
+	if nr, ok := cart.ParseCartId(id); ok {
+		return uint64(nr), true
+	}
+	return 0, false
+}
+
+func isValidFileId(name string) (uint64, bool) {
+
+	parts := strings.Split(name, ".")
+	if len(parts) > 1 && parts[1] == "events" {
+		idStr := parts[0]
+
+		return isValidId(idStr)
+	}
+	return 0, false
+}
+
+// func AccessTime(info os.FileInfo) (time.Time, bool) {
+// 	switch stat := info.Sys().(type) {
+// 	case *syscall.Stat_t:
+// 		// Linux: Atim; macOS/BSD: Atimespec
+// 		// Use reflection or build tags if naming differs.
+// 		// Linux:
+// 		if stat.Atim.Sec != 0 || stat.Atim.Nsec != 0 {
+// 			return time.Unix(int64(stat.Atim.Sec), int64(stat.Atim.Nsec)), true
+// 		}
+// 		// macOS/BSD example (uncomment if needed):
+// 		//return time.Unix(int64(stat.Atimespec.Sec), int64(stat.Atimespec.Nsec)), true
+// 	}
+// 	return time.Time{}, false
+// }
+
+func appendFileInfo(info fs.FileInfo, out *CartFileInfo) *CartFileInfo {
+	//sys := info.Sys()
+	//fmt.Printf("sys type %T", sys)
+	out.Size = info.Size()
+	out.Modified = info.ModTime()
+	//out.Accessed, _ = AccessTime(info)
+	return out
+}
+
+// var cartFileRe = regexp.MustCompile(`^(\d+)\.events\.log$`)
+
+func listCartFiles(dir string) ([]*CartFileInfo, error) {
+	entries, err := os.ReadDir(dir)
+	if err != nil {
+		if errors.Is(err, os.ErrNotExist) {
+			return []*CartFileInfo{}, nil
+		}
+		return nil, err
+	}
+	out := make([]*CartFileInfo, 0)
+	for _, e := range entries {
+		if e.IsDir() {
+			continue
+		}
+		id, valid := isValidFileId(e.Name())
+		if !valid {
+			continue
+		}
+
+		info, err := e.Info()
+		if err != nil {
+			continue
+		}
+		info.Sys()
+		out = append(out, appendFileInfo(info, &CartFileInfo{
+			ID:     fmt.Sprintf("%d", id),
+			CartId: cart.CartId(id),
+		}))
+	}
+	return out, nil
+}
+
+func readRawLogLines(path string) ([]json.RawMessage, error) {
+	fh, err := os.Open(path)
+	if err != nil {
+		return nil, err
+	}
+	defer fh.Close()
+	lines := make([]json.RawMessage, 0, 64)
+	s := bufio.NewScanner(fh)
+	// increase buffer to handle larger JSON lines
+	buf := make([]byte, 0, 1024*1024)
+	s.Buffer(buf, 1024*1024)
+	for s.Scan() {
+		line := s.Bytes()
+		if line == nil {
+			continue
+		}
+		lines = append(lines, line)
+	}
+	if err := s.Err(); err != nil {
+		return nil, err
+	}
+	return lines, nil
+}
+
+func writeJSON(w http.ResponseWriter, status int, v any) {
+	w.Header().Set("Content-Type", "application/json")
+	w.Header().Set("Cache-Control", "no-cache")
+	w.WriteHeader(status)
+	_ = json.NewEncoder(w).Encode(v)
+}
+
+func (fs *FileServer) CartsHandler(w http.ResponseWriter, r *http.Request) {
+	list, err := listCartFiles(fs.dataDir)
+	if err != nil {
+		writeJSON(w, http.StatusInternalServerError, map[string]string{"error": err.Error()})
+		return
+	}
+	// sort by modified desc
+	sort.Slice(list, func(i, j int) bool { return list[i].Modified.After(list[j].Modified) })
+
+	writeJSON(w, http.StatusOK, map[string]any{
+		"count": len(list),
+		"carts": list,
+	})
+}
+
+func (fs *FileServer) PromotionsHandler(w http.ResponseWriter, r *http.Request) {
+	fileName := filepath.Join(fs.dataDir, "promotions.json")
+	if r.Method == http.MethodGet {
+		file, err := os.Open(fileName)
+		if err != nil {
+			writeJSON(w, http.StatusInternalServerError, map[string]string{"error": err.Error()})
+			return
+		}
+		defer file.Close()
+
+		io.Copy(w, file)
+		return
+	}
+	if r.Method == http.MethodPost {
+		file, err := os.Create(fileName)
+		if err != nil {
+			writeJSON(w, http.StatusInternalServerError, map[string]string{"error": err.Error()})
+			return
+		}
+		defer file.Close()
+
+		io.Copy(file, r.Body)
+		return
+	}
+
+	w.WriteHeader(http.StatusMethodNotAllowed)
+}
+
+func (fs *FileServer) VoucherHandler(w http.ResponseWriter, r *http.Request) {
+	fileName := filepath.Join(fs.dataDir, "vouchers.json")
+	if r.Method == http.MethodGet {
+		file, err := os.Open(fileName)
+		if err != nil {
+			writeJSON(w, http.StatusInternalServerError, map[string]string{"error": err.Error()})
+			return
+		}
+		defer file.Close()
+
+		io.Copy(w, file)
+		return
+	}
+	if r.Method == http.MethodPost {
+		file, err := os.Create(fileName)
+		if err != nil {
+			writeJSON(w, http.StatusInternalServerError, map[string]string{"error": err.Error()})
+			return
+		}
+		defer file.Close()
+
+		io.Copy(file, r.Body)
+		return
+	}
+
+	w.WriteHeader(http.StatusMethodNotAllowed)
+}
+
+func (fs *FileServer) PromotionPartHandler(w http.ResponseWriter, r *http.Request) {
+	idStr := r.PathValue("id")
+	if idStr == "" {
+		w.WriteHeader(http.StatusBadRequest)
+		fmt.Fprintf(w, "missing id")
+		return
+	}
+	_, ok := isValidId(idStr)
+	if !ok {
+		w.WriteHeader(http.StatusBadRequest)
+		fmt.Fprintf(w, "invalid id %s", idStr)
+		return
+	}
+	w.WriteHeader(http.StatusNotImplemented)
+}
+
+type JsonError struct {
+	Error string `json:"error"`
+}
+
+func (fs *FileServer) CartHandler(w http.ResponseWriter, r *http.Request) {
+	idStr := r.PathValue("id")
+	if idStr == "" {
+		writeJSON(w, http.StatusBadRequest, JsonError{Error: "missing id"})
+		return
+	}
+	id, ok := isValidId(idStr)
+	if !ok {
+		writeJSON(w, http.StatusBadRequest, JsonError{Error: "invalid id"})
+		return
+	}
+	// reconstruct state from event log if present
+	grain := cart.NewCartGrain(id, time.Now())
+
+	err := fs.storage.LoadEvents(id, grain)
+	if err != nil {
+		writeJSON(w, http.StatusInternalServerError, JsonError{Error: err.Error()})
+		return
+	}
+
+	path := filepath.Join(fs.dataDir, fmt.Sprintf("%d.events.log", id))
+	info, err := os.Stat(path)
+	if err != nil && errors.Is(err, os.ErrNotExist) {
+		writeJSON(w, http.StatusNotFound, JsonError{Error: "cart not found"})
+		return
+	} else if err != nil {
+		writeJSON(w, http.StatusInternalServerError, JsonError{Error: err.Error()})
+		return
+	}
+	lines, err := readRawLogLines(path)
+	if err != nil {
+		writeJSON(w, http.StatusInternalServerError, JsonError{Error: err.Error()})
+		return
+	}
+	writeJSON(w, http.StatusOK, map[string]any{
+		"id":        id,
+		"cartId":    cart.CartId(id).String(),
+		"state":     grain,
+		"mutations": lines,
+		"meta": map[string]any{
+			"size":     info.Size(),
+			"modified": info.ModTime(),
+			"path":     path,
+		},
+	})
+}

cmd/backoffice/fileserver_test.go

@@ -0,0 +1,89 @@
+package main
+
+import (
+	"math/rand"
+	"os"
+	"path/filepath"
+	"testing"
+	"time"
+
+	"git.tornberg.me/go-cart-actor/pkg/cart"
+)
+
+// TestAppendFileInfoRandomProjectFile picks a random existing .go source file in the
+// repository (from a small curated list to keep the test hermetic) and verifies
+// that appendFileInfo populates Size, Modified and System without mutating the
+// identity fields (ID, CartId). The randomness is only to satisfy the requirement
+// of using "a random project file"; the test behavior is deterministic enough for
+// CI because all chosen files are expected to exist.
+func TestAppendFileInfoRandomProjectFile(t *testing.T) {
+	candidates := []string{
+		filepath.FromSlash("../../pkg/cart/cart_id.go"),
+		filepath.FromSlash("../../pkg/actor/grain.go"),
+		filepath.FromSlash("../../cmd/cart/main.go"),
+	}
+	// Pick one at random.
+	rand.Seed(time.Now().UnixNano())
+	path := candidates[rand.Intn(len(candidates))]
+
+	info, err := os.Stat(path)
+	if err != nil {
+		t.Fatalf("stat failed for %s: %v", path, err)
+	}
+
+	// Pre-populate a CartFileInfo with identity fields.
+	origID := "test-id"
+	origCartId := cart.CartId(12345)
+	cf := &CartFileInfo{ID: origID, CartId: origCartId}
+
+	// Call function under test.
+	got := appendFileInfo(info, cf)
+
+	if got != cf {
+		t.Fatalf("appendFileInfo should return the same pointer instance")
+	}
+
+	if cf.ID != origID {
+		t.Fatalf("ID mutated: expected %q got %q", origID, cf.ID)
+	}
+	if cf.CartId != origCartId {
+		t.Fatalf("CartId mutated: expected %v got %v", origCartId, cf.CartId)
+	}
+
+	if cf.Size != info.Size() {
+		t.Fatalf("Size mismatch: expected %d got %d", info.Size(), cf.Size)
+	}
+
+	mod := info.ModTime()
+	// Allow small clock skew / coarse timestamp truncation.
+	if cf.Modified.Before(mod.Add(-2*time.Second)) || cf.Modified.After(mod.Add(2*time.Second)) {
+		t.Fatalf("Modified not within expected range: want ~%v got %v", mod, cf.Modified)
+	}
+
+}
+
+// TestAppendFileInfoTempFile creates a temporary file to ensure Size and Modified
+// are updated for a freshly written file with known content length.
+func TestAppendFileInfoTempFile(t *testing.T) {
+	dir := t.TempDir()
+	path := filepath.Join(dir, "temp.events.log")
+	content := []byte("hello world\nanother line\n")
+	if err := os.WriteFile(path, content, 0644); err != nil {
+		t.Fatalf("write temp file failed: %v", err)
+	}
+
+	info, err := os.Stat(path)
+	if err != nil {
+		t.Fatalf("stat temp file failed: %v", err)
+	}
+
+	cf := &CartFileInfo{ID: "temp", CartId: cart.CartId(0)}
+	appendFileInfo(info, cf)
+
+	if cf.Size != int64(len(content)) {
+		t.Fatalf("expected Size %d got %d", len(content), cf.Size)
+	}
+	if cf.Modified.IsZero() {
+		t.Fatalf("Modified should be set")
+	}
+}

cmd/backoffice/hub.go

@@ -0,0 +1,248 @@
+package main
+
+import (
+	"bufio"
+	"crypto/sha1"
+	"encoding/base64"
+	"encoding/binary"
+	"io"
+	"net"
+	"net/http"
+	"strings"
+	"time"
+)
+
+// Hub manages websocket clients and broadcasts messages to them.
+type Hub struct {
+	register   chan *Client
+	unregister chan *Client
+	broadcast  chan []byte
+	clients    map[*Client]bool
+}
+
+// Client represents a single websocket client connection.
+type Client struct {
+	hub  *Hub
+	conn net.Conn
+	send chan []byte
+}
+
+// NewHub constructs a new Hub instance.
+func NewHub() *Hub {
+	return &Hub{
+		register:   make(chan *Client),
+		unregister: make(chan *Client),
+		broadcast:  make(chan []byte, 1024),
+		clients:    make(map[*Client]bool),
+	}
+}
+
+// Run starts the hub event loop.
+func (h *Hub) Run() {
+	for {
+		select {
+		case c := <-h.register:
+			h.clients[c] = true
+		case c := <-h.unregister:
+			if _, ok := h.clients[c]; ok {
+				delete(h.clients, c)
+				close(c.send)
+				_ = c.conn.Close()
+			}
+		case msg := <-h.broadcast:
+			for c := range h.clients {
+				select {
+				case c.send <- msg:
+				default:
+					// Client is slow or dead; drop it.
+					delete(h.clients, c)
+					close(c.send)
+					_ = c.conn.Close()
+				}
+			}
+		}
+	}
+}
+
+// computeAccept computes the Sec-WebSocket-Accept header value.
+func computeAccept(key string) string {
+	const magic = "258EAFA5-E914-47DA-95CA-C5AB0DC85B11"
+	h := sha1.New()
+	h.Write([]byte(key + magic))
+	return base64.StdEncoding.EncodeToString(h.Sum(nil))
+}
+
+// ServeWS upgrades the HTTP request to a WebSocket connection and registers a client.
+func (h *Hub) ServeWS(w http.ResponseWriter, r *http.Request) {
+	if !strings.Contains(strings.ToLower(r.Header.Get("Connection")), "upgrade") || strings.ToLower(r.Header.Get("Upgrade")) != "websocket" {
+		http.Error(w, "upgrade required", http.StatusBadRequest)
+		return
+	}
+	key := r.Header.Get("Sec-WebSocket-Key")
+	if key == "" {
+		http.Error(w, "missing Sec-WebSocket-Key", http.StatusBadRequest)
+		return
+	}
+	accept := computeAccept(key)
+
+	hj, ok := w.(http.Hijacker)
+	if !ok {
+		http.Error(w, "websocket not supported", http.StatusInternalServerError)
+		return
+	}
+	conn, buf, err := hj.Hijack()
+	if err != nil {
+		return
+	}
+
+	// Write the upgrade response
+	response := "HTTP/1.1 101 Switching Protocols\r\n" +
+		"Upgrade: websocket\r\n" +
+		"Connection: Upgrade\r\n" +
+		"Sec-WebSocket-Accept: " + accept + "\r\n" +
+		"\r\n"
+	if _, err := buf.WriteString(response); err != nil {
+		_ = conn.Close()
+		return
+	}
+	if err := buf.Flush(); err != nil {
+		_ = conn.Close()
+		return
+	}
+
+	client := &Client{
+		hub:  h,
+		conn: conn,
+		send: make(chan []byte, 256),
+	}
+	h.register <- client
+	go client.writePump()
+	go client.readPump()
+}
+
+// writeWSFrame writes a single WebSocket frame to the writer.
+func writeWSFrame(w io.Writer, opcode byte, payload []byte) error {
+	// FIN set, opcode as provided
+	header := []byte{0x80 | (opcode & 0x0F)}
+	l := len(payload)
+	switch {
+	case l < 126:
+		header = append(header, byte(l))
+	case l <= 65535:
+		ext := make([]byte, 2)
+		binary.BigEndian.PutUint16(ext, uint16(l))
+		header = append(header, 126)
+		header = append(header, ext...)
+	default:
+		ext := make([]byte, 8)
+		binary.BigEndian.PutUint64(ext, uint64(l))
+		header = append(header, 127)
+		header = append(header, ext...)
+	}
+	if _, err := w.Write(header); err != nil {
+		return err
+	}
+	if l > 0 {
+		if _, err := w.Write(payload); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// readPump handles control frames from the client and discards other incoming frames.
+// This server is broadcast-only to clients.
+func (c *Client) readPump() {
+	defer func() {
+		c.hub.unregister <- c
+	}()
+	reader := bufio.NewReader(c.conn)
+	for {
+		// Read first two bytes
+		b1, err := reader.ReadByte()
+		if err != nil {
+			return
+		}
+		b2, err := reader.ReadByte()
+		if err != nil {
+			return
+		}
+		opcode := b1 & 0x0F
+		masked := (b2 & 0x80) != 0
+		length := int64(b2 & 0x7F)
+		if length == 126 {
+			ext := make([]byte, 2)
+			if _, err := io.ReadFull(reader, ext); err != nil {
+				return
+			}
+			length = int64(binary.BigEndian.Uint16(ext))
+		} else if length == 127 {
+			ext := make([]byte, 8)
+			if _, err := io.ReadFull(reader, ext); err != nil {
+				return
+			}
+			length = int64(binary.BigEndian.Uint64(ext))
+		}
+		var maskKey [4]byte
+		if masked {
+			if _, err := io.ReadFull(reader, maskKey[:]); err != nil {
+				return
+			}
+		}
+
+		// Handle Ping -> Pong
+		if opcode == 0x9 && length <= 125 {
+			payload := make([]byte, length)
+			if _, err := io.ReadFull(reader, payload); err != nil {
+				return
+			}
+			// Unmask if masked
+			if masked {
+				for i := int64(0); i < length; i++ {
+					payload[i] ^= maskKey[i%4]
+				}
+			}
+			_ = writeWSFrame(c.conn, 0xA, payload) // best-effort pong
+			continue
+		}
+
+		// Close frame
+		if opcode == 0x8 {
+			// Drain payload if any, then exit
+			if _, err := io.CopyN(io.Discard, reader, length); err != nil {
+				return
+			}
+			return
+		}
+
+		// For other frames, just discard payload
+		if _, err := io.CopyN(io.Discard, reader, length); err != nil {
+			return
+		}
+	}
+}
+
+// writePump sends queued messages to the client and pings periodically to keep the connection alive.
+func (c *Client) writePump() {
+	ticker := time.NewTicker(30 * time.Second)
+	defer func() {
+		ticker.Stop()
+		_ = c.conn.Close()
+	}()
+	for {
+		select {
+		case msg, ok := <-c.send:
+			if !ok {
+				// try to send close frame
+				_ = writeWSFrame(c.conn, 0x8, nil)
+				return
+			}
+			if err := writeWSFrame(c.conn, 0x1, msg); err != nil {
+				return
+			}
+		case <-ticker.C:
+			// Send a ping to keep connections alive behind proxies
+			_ = writeWSFrame(c.conn, 0x9, []byte("ping"))
+		}
+	}
+}

cmd/backoffice/main.go

@@ -0,0 +1,152 @@
+package main
+
+import (
+	"context"
+	"errors"
+	"log"
+	"net/http"
+	"os"
+	"time"
+
+	actor "git.tornberg.me/go-cart-actor/pkg/actor"
+	"git.tornberg.me/go-cart-actor/pkg/cart"
+	"github.com/matst80/slask-finder/pkg/messaging"
+	amqp "github.com/rabbitmq/amqp091-go"
+)
+
+type CartFileInfo struct {
+	ID       string      `json:"id"`
+	CartId   cart.CartId `json:"cartId"`
+	Size     int64       `json:"size"`
+	Modified time.Time   `json:"modified"`
+}
+
+func envOrDefault(key, def string) string {
+	if v := os.Getenv(key); v != "" {
+		return v
+	}
+	return def
+}
+
+func startMutationConsumer(ctx context.Context, conn *amqp.Connection, hub *Hub) error {
+	ch, err := conn.Channel()
+	if err != nil {
+		_ = conn.Close()
+		return err
+	}
+	msgs, err := messaging.DeclareBindAndConsume(ch, "cart", "mutation")
+	if err != nil {
+		_ = ch.Close()
+		return err
+	}
+
+	go func() {
+		defer ch.Close()
+
+		for {
+			select {
+			case <-ctx.Done():
+				return
+			case m, ok := <-msgs:
+				if !ok {
+					log.Fatalf("connection closed")
+					continue
+				}
+				// Log and broadcast to all websocket clients
+				log.Printf("mutation event: %s", string(m.Body))
+
+				if hub != nil {
+					select {
+					case hub.broadcast <- m.Body:
+					default:
+						// if hub queue is full, drop to avoid blocking
+					}
+				}
+				if err := m.Ack(false); err != nil {
+					log.Printf("error acknowledging message: %v", err)
+				}
+			}
+		}
+	}()
+	return nil
+}
+
+func main() {
+	dataDir := envOrDefault("DATA_DIR", "data")
+	addr := envOrDefault("ADDR", ":8080")
+	amqpURL := os.Getenv("AMQP_URL")
+
+	_ = os.MkdirAll(dataDir, 0755)
+
+	reg := cart.NewCartMultationRegistry()
+	diskStorage := actor.NewDiskStorage[cart.CartGrain](dataDir, reg)
+
+	fs := NewFileServer(dataDir, diskStorage)
+
+	hub := NewHub()
+	go hub.Run()
+
+	mux := http.NewServeMux()
+	mux.HandleFunc("GET /carts", fs.CartsHandler)
+	mux.HandleFunc("GET /cart/{id}", fs.CartHandler)
+	mux.HandleFunc("/promotions", fs.PromotionsHandler)
+	mux.HandleFunc("/vouchers", fs.VoucherHandler)
+	mux.HandleFunc("/promotion/{id}", fs.PromotionPartHandler)
+
+	mux.HandleFunc("/ws", hub.ServeWS)
+	mux.HandleFunc("/healthz", func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(http.StatusOK)
+		_, _ = w.Write([]byte("ok"))
+	})
+	mux.HandleFunc("/readyz", func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(http.StatusOK)
+		_, _ = w.Write([]byte("ok"))
+	})
+	mux.HandleFunc("/livez", func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(http.StatusOK)
+		_, _ = w.Write([]byte("ok"))
+	})
+
+	// Global CORS middleware allowing all origins and handling preflight
+	handler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Access-Control-Allow-Origin", "*")
+		w.Header().Set("Access-Control-Allow-Methods", "GET, POST, PUT, PATCH, DELETE, OPTIONS")
+		w.Header().Set("Access-Control-Allow-Headers", "Content-Type, Authorization, X-Requested-With")
+		w.Header().Set("Access-Control-Expose-Headers", "*")
+		if r.Method == http.MethodOptions {
+			w.WriteHeader(http.StatusNoContent)
+			return
+		}
+		mux.ServeHTTP(w, r)
+	})
+
+	srv := &http.Server{
+		Addr:         addr,
+		Handler:      handler,
+		ReadTimeout:  15 * time.Second,
+		WriteTimeout: 30 * time.Second,
+		IdleTimeout:  60 * time.Second,
+	}
+
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
+	if amqpURL != "" {
+		conn, err := amqp.Dial(amqpURL)
+		if err != nil {
+			log.Fatalf("failed to connect to RabbitMQ: %v", err)
+		}
+		if err := startMutationConsumer(ctx, conn, hub); err != nil {
+			log.Printf("AMQP listener disabled: %v", err)
+		} else {
+			log.Printf("AMQP listener connected")
+		}
+	}
+
+	log.Printf("backoffice HTTP listening on %s (dataDir=%s)", addr, dataDir)
+	if err := srv.ListenAndServe(); err != nil && !errors.Is(err, http.ErrServerClosed) {
+		log.Fatalf("http server error: %v", err)
+	}
+
+	// server stopped
+}

cmd/cart/amqp-order-handler.go

@@ -0,0 +1,63 @@
+package main
+
+import (
+	"context"
+	"fmt"
+	"time"
+
+	amqp "github.com/rabbitmq/amqp091-go"
+)
+
+type AmqpOrderHandler struct {
+	conn *amqp.Connection
+}
+
+func NewAmqpOrderHandler(conn *amqp.Connection) *AmqpOrderHandler {
+	return &AmqpOrderHandler{
+		conn: conn,
+	}
+}
+
+func (h *AmqpOrderHandler) DefineTopics() error {
+	ch, err := h.conn.Channel()
+	if err != nil {
+		return fmt.Errorf("failed to open a channel: %w", err)
+	}
+	defer ch.Close()
+
+	err = ch.ExchangeDeclare(
+		"orders", // name
+		"direct", // type
+		true,     // durable
+		false,    // auto-deleted
+		false,    // internal
+		false,    // no-wait
+		nil,      // arguments
+	)
+	if err != nil {
+		return fmt.Errorf("failed to declare an exchange: %w", err)
+	}
+
+	return nil
+}
+
+func (h *AmqpOrderHandler) OrderCompleted(body []byte) error {
+	ch, err := h.conn.Channel()
+	if err != nil {
+		return fmt.Errorf("failed to open a channel: %w", err)
+	}
+	defer ch.Close()
+	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+	defer cancel()
+
+	return ch.PublishWithContext(ctx,
+		"orders", // exchange
+		"new",    // routing key
+		false,    // mandatory
+		false,    // immediate
+		amqp.Publishing{
+			ContentType: "application/json",
+			Body:        body,
+		})
+
+}

cmd/cart/checkout_builder.go

@@ -3,6 +3,8 @@ package main
 import (
 	"encoding/json"
 	"fmt"
+
+	"git.tornberg.me/go-cart-actor/pkg/cart"
 )
 
 // CheckoutMeta carries the external / URL metadata required to build a
@@ -33,7 +35,7 @@ type CheckoutMeta struct {
 //
 // If you later need to support different tax rates per line, you can extend
 // CartItem / Delivery to expose that data and propagate it here.
-func BuildCheckoutOrderPayload(grain *CartGrain, meta *CheckoutMeta) ([]byte, *CheckoutOrder, error) {
+func BuildCheckoutOrderPayload(grain *cart.CartGrain, meta *CheckoutMeta) ([]byte, *CheckoutOrder, error) {
 	if grain == nil {
 		return nil, nil, fmt.Errorf("nil grain")
 	}
@@ -64,20 +66,20 @@ func BuildCheckoutOrderPayload(grain *CartGrain, meta *CheckoutMeta) ([]byte, *C
 		lines = append(lines, &Line{
 			Type:           "physical",
 			Reference:      it.Sku,
-			Name:           it.Name,
+			Name:           it.Meta.Name,
 			Quantity:       it.Quantity,
-			UnitPrice:      int(it.Price),
+			UnitPrice:      int(it.Price.IncVat),
 			TaxRate:        2500, // TODO: derive if variable tax rates are introduced
 			QuantityUnit:   "st",
-			TotalAmount:    int(it.TotalPrice),
+			TotalAmount:    int(it.TotalPrice.IncVat),
-			TotalTaxAmount: int(it.TotalTax),
+			TotalTaxAmount: int(it.TotalPrice.TotalVat()),
-			ImageURL:       fmt.Sprintf("https://www.elgiganten.se%s", it.Image),
+			ImageURL:       fmt.Sprintf("https://www.elgiganten.se%s", it.Meta.Image),
 		})
 	}
 
 	// Delivery lines
 	for _, d := range grain.Deliveries {
-		if d == nil || d.Price <= 0 {
+		if d == nil || d.Price.IncVat <= 0 {
 			continue
 		}
 		lines = append(lines, &Line{
@@ -85,11 +87,11 @@ func BuildCheckoutOrderPayload(grain *CartGrain, meta *CheckoutMeta) ([]byte, *C
 			Reference:      d.Provider,
 			Name:           "Delivery",
 			Quantity:       1,
-			UnitPrice:      int(d.Price),
+			UnitPrice:      int(d.Price.IncVat),
 			TaxRate:        2500,
 			QuantityUnit:   "st",
-			TotalAmount:    int(d.Price),
+			TotalAmount:    int(d.Price.IncVat),
-			TotalTaxAmount: int(GetTaxAmount(d.Price, 2500)),
+			TotalTaxAmount: int(d.Price.TotalVat()),
 		})
 	}
 
@@ -97,8 +99,8 @@ func BuildCheckoutOrderPayload(grain *CartGrain, meta *CheckoutMeta) ([]byte, *C
 		PurchaseCountry:    country,
 		PurchaseCurrency:   currency,
 		Locale:             locale,
-		OrderAmount:        int(grain.TotalPrice),
+		OrderAmount:        int(grain.TotalPrice.IncVat),
-		OrderTaxAmount:     int(grain.TotalTax),
+		OrderTaxAmount:     int(grain.TotalPrice.TotalVat()),
 		OrderLines:         lines,
 		MerchantReference1: grain.Id.String(),
 		MerchantURLS: &CheckoutMerchantURLS{

cmd/cart/checkout_server.go

@@ -0,0 +1,120 @@
+package main
+
+import (
+	"encoding/json"
+	"fmt"
+	"log"
+	"net/http"
+	"time"
+
+	"git.tornberg.me/go-cart-actor/pkg/actor"
+	"git.tornberg.me/go-cart-actor/pkg/cart"
+	amqp "github.com/rabbitmq/amqp091-go"
+)
+
+func (a *App) HandleCheckoutRequests(amqpUrl string, mux *http.ServeMux) {
+	conn, err := amqp.Dial(amqpUrl)
+	if err != nil {
+		log.Fatalf("failed to connect to RabbitMQ: %v", err)
+	}
+
+	amqpListener := actor.NewAmqpListener(conn, func(id uint64, msg []actor.ApplyResult) (any, error) {
+		return &CartChangeEvent{
+			CartId:    cart.CartId(id),
+			Mutations: msg,
+		}, nil
+	})
+	amqpListener.DefineTopics()
+	a.pool.AddListener(amqpListener)
+	orderHandler := NewAmqpOrderHandler(conn)
+	orderHandler.DefineTopics()
+
+	mux.HandleFunc("/push", func(w http.ResponseWriter, r *http.Request) {
+
+		if r.Method != http.MethodPost {
+			w.WriteHeader(http.StatusMethodNotAllowed)
+			return
+		}
+		orderId := r.URL.Query().Get("order_id")
+		log.Printf("Order confirmation push: %s", orderId)
+
+		order, err := a.klarnaClient.GetOrder(orderId)
+
+		if err != nil {
+			log.Printf("Error creating request: %v\n", err)
+			w.WriteHeader(http.StatusInternalServerError)
+			return
+		}
+
+		err = confirmOrder(order, orderHandler)
+		if err != nil {
+			log.Printf("Error confirming order: %v\n", err)
+			w.WriteHeader(http.StatusInternalServerError)
+			return
+		}
+
+		err = triggerOrderCompleted(a.server, order)
+		if err != nil {
+			log.Printf("Error processing cart message: %v\n", err)
+			w.WriteHeader(http.StatusInternalServerError)
+			return
+		}
+		err = a.klarnaClient.AcknowledgeOrder(orderId)
+		if err != nil {
+			log.Printf("Error acknowledging order: %v\n", err)
+		}
+
+		w.WriteHeader(http.StatusOK)
+	})
+
+	mux.HandleFunc("/checkout", a.server.CheckoutHandler(func(order *CheckoutOrder, w http.ResponseWriter) error {
+		w.Header().Set("Content-Type", "text/html; charset=utf-8")
+		w.Header().Set("Permissions-Policy", "payment=(self \"https://js.stripe.com\" \"https://m.stripe.network\" \"https://js.playground.kustom.co\")")
+		w.WriteHeader(http.StatusOK)
+		_, err := fmt.Fprintf(w, tpl, order.HTMLSnippet)
+		return err
+	}))
+
+	mux.HandleFunc("/confirmation/{order_id}", func(w http.ResponseWriter, r *http.Request) {
+
+		orderId := r.PathValue("order_id")
+		order, err := a.klarnaClient.GetOrder(orderId)
+
+		if err != nil {
+			w.WriteHeader(http.StatusInternalServerError)
+			w.Write([]byte(err.Error()))
+			return
+		}
+
+		w.Header().Set("Content-Type", "text/html; charset=utf-8")
+		if order.Status == "checkout_complete" {
+			http.SetCookie(w, &http.Cookie{
+				Name:     "cartid",
+				Value:    "",
+				Path:     "/",
+				Secure:   true,
+				HttpOnly: true,
+				Expires:  time.Unix(0, 0),
+				SameSite: http.SameSiteLaxMode,
+			})
+		}
+
+		w.WriteHeader(http.StatusOK)
+		fmt.Fprintf(w, tpl, order.HTMLSnippet)
+	})
+	mux.HandleFunc("/validate", func(w http.ResponseWriter, r *http.Request) {
+		log.Printf("Klarna order validation, method: %s", r.Method)
+		if r.Method != "POST" {
+			w.WriteHeader(http.StatusMethodNotAllowed)
+			return
+		}
+		order := &CheckoutOrder{}
+		err := json.NewDecoder(r.Body).Decode(order)
+		if err != nil {
+			w.WriteHeader(http.StatusBadRequest)
+		}
+		log.Printf("Klarna order validation: %s", order.ID)
+
+		w.WriteHeader(http.StatusOK)
+	})
+}

cmd/cart/k8s-host-discovery.go

@@ -0,0 +1,60 @@
+package main
+
+import (
+	"log"
+
+	"git.tornberg.me/go-cart-actor/pkg/actor"
+	"git.tornberg.me/go-cart-actor/pkg/cart"
+	"git.tornberg.me/go-cart-actor/pkg/discovery"
+	"k8s.io/apimachinery/pkg/watch"
+	"k8s.io/client-go/kubernetes"
+	"k8s.io/client-go/rest"
+)
+
+func GetDiscovery() discovery.Discovery {
+	if podIp == "" {
+		return nil
+	}
+
+	config, kerr := rest.InClusterConfig()
+
+	if kerr != nil {
+		log.Fatalf("Error creating kubernetes client: %v\n", kerr)
+	}
+	client, err := kubernetes.NewForConfig(config)
+	if err != nil {
+		log.Fatalf("Error creating client: %v\n", err)
+	}
+	return discovery.NewK8sDiscovery(client)
+}
+
+func UseDiscovery(pool actor.GrainPool[*cart.CartGrain]) {
+
+	go func(hw discovery.Discovery) {
+		if hw == nil {
+			log.Print("No discovery service available")
+			return
+		}
+		ch, err := hw.Watch()
+		if err != nil {
+			log.Printf("Discovery error: %v", err)
+			return
+		}
+		for evt := range ch {
+			if evt.Host == "" {
+				continue
+			}
+			switch evt.Type {
+			case watch.Deleted:
+				if pool.IsKnown(evt.Host) {
+					pool.RemoveHost(evt.Host)
+				}
+			default:
+				if !pool.IsKnown(evt.Host) {
+					log.Printf("Discovered host %s", evt.Host)
+					pool.AddRemoteHost(evt.Host)
+				}
+			}
+		}
+	}(GetDiscovery())
+}

cmd/cart/main.go

@@ -0,0 +1,279 @@
+package main
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"log"
+	"net"
+	"net/http"
+	"net/http/pprof"
+	"os"
+	"os/signal"
+	"strings"
+	"time"
+
+	"git.tornberg.me/go-cart-actor/pkg/actor"
+	"git.tornberg.me/go-cart-actor/pkg/cart"
+	messages "git.tornberg.me/go-cart-actor/pkg/messages"
+	"git.tornberg.me/go-cart-actor/pkg/promotions"
+	"git.tornberg.me/go-cart-actor/pkg/proxy"
+	"git.tornberg.me/go-cart-actor/pkg/voucher"
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/client_golang/prometheus/promauto"
+	"github.com/prometheus/client_golang/prometheus/promhttp"
+	"go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp"
+)
+
+var (
+	grainSpawns = promauto.NewCounter(prometheus.CounterOpts{
+		Name: "cart_grain_spawned_total",
+		Help: "The total number of spawned grains",
+	})
+)
+
+func init() {
+	os.Mkdir("data", 0755)
+}
+
+type App struct {
+	pool         *actor.SimpleGrainPool[cart.CartGrain]
+	server       *PoolServer
+	klarnaClient *KlarnaClient
+}
+
+var podIp = os.Getenv("POD_IP")
+var name = os.Getenv("POD_NAME")
+var amqpUrl = os.Getenv("AMQP_URL")
+
+var tpl = `<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="UTF-8" />
+    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
+    <title>s10r testing - checkout</title>
+  </head>
+
+  <body>
+    %s
+  </body>
+</html>
+`
+
+func getCountryFromHost(host string) string {
+	if strings.Contains(strings.ToLower(host), "-no") {
+		return "no"
+	}
+	if strings.Contains(strings.ToLower(host), "-se") {
+		return "se"
+	}
+	return ""
+}
+
+type MutationContext struct {
+	VoucherService voucher.Service
+}
+
+type CartChangeEvent struct {
+	CartId    cart.CartId         `json:"cartId"`
+	Mutations []actor.ApplyResult `json:"mutations"`
+}
+
+func main() {
+
+	controlPlaneConfig := actor.DefaultServerConfig()
+
+	promotionData, err := promotions.LoadStateFile("data/promotions.json")
+	if err != nil {
+		log.Printf("Error loading promotions: %v\n", err)
+	}
+
+	log.Printf("loaded %d promotions", len(promotionData.State.Promotions))
+
+	promotionService := promotions.NewPromotionService(nil)
+
+	reg := cart.NewCartMultationRegistry()
+	reg.RegisterProcessor(
+		actor.NewMutationProcessor(func(g *cart.CartGrain) error {
+			g.UpdateTotals()
+			ctx := promotions.NewContextFromCart(g, promotions.WithNow(time.Now()), promotions.WithCustomerSegment("vip"))
+			_, actions := promotionService.EvaluateAll(promotionData.State.Promotions, ctx)
+			for _, action := range actions {
+				log.Printf("apply: %+v", action)
+				g.UpdateTotals()
+			}
+			return nil
+		}),
+	)
+
+	diskStorage := actor.NewDiskStorage[cart.CartGrain]("data", reg)
+	poolConfig := actor.GrainPoolConfig[cart.CartGrain]{
+		MutationRegistry: reg,
+		Storage:          diskStorage,
+		Spawn: func(id uint64) (actor.Grain[cart.CartGrain], error) {
+			grainSpawns.Inc()
+			ret := cart.NewCartGrain(id, time.Now())
+			// Set baseline lastChange at spawn; replay may update it to last event timestamp.
+
+			err := diskStorage.LoadEvents(id, ret)
+
+			return ret, err
+		},
+		SpawnHost: func(host string) (actor.Host, error) {
+			return proxy.NewRemoteHost(host)
+		},
+		TTL:      15 * time.Minute,
+		PoolSize: 2 * 65535,
+		Hostname: podIp,
+	}
+
+	pool, err := actor.NewSimpleGrainPool(poolConfig)
+	if err != nil {
+		log.Fatalf("Error creating cart pool: %v\n", err)
+	}
+
+	klarnaClient := NewKlarnaClient(KlarnaPlaygroundUrl, os.Getenv("KLARNA_API_USERNAME"), os.Getenv("KLARNA_API_PASSWORD"))
+
+	syncedServer := NewPoolServer(pool, fmt.Sprintf("%s, %s", name, podIp), klarnaClient)
+
+	app := &App{
+		pool:         pool,
+		server:       syncedServer,
+		klarnaClient: klarnaClient,
+	}
+
+	mux := http.NewServeMux()
+	debugMux := http.NewServeMux()
+
+	if amqpUrl == "" {
+		log.Printf("no connection to amqp defined")
+	} else {
+		app.HandleCheckoutRequests(amqpUrl, mux)
+	}
+
+	grpcSrv, err := actor.NewControlServer[*cart.CartGrain](controlPlaneConfig, pool)
+	if err != nil {
+		log.Fatalf("Error starting control plane gRPC server: %v\n", err)
+	}
+	defer grpcSrv.GracefulStop()
+
+	// go diskStorage.SaveLoop(10 * time.Second)
+	UseDiscovery(pool)
+
+	ctx, stop := signal.NotifyContext(context.Background(), os.Interrupt)
+	defer stop()
+
+	otelShutdown, err := setupOTelSDK(ctx)
+	if err != nil {
+		log.Fatalf("Unable to start otel %v", err)
+	}
+
+	syncedServer.Serve(mux)
+	// only for local
+	mux.HandleFunc("GET /add/remote/{host}", func(w http.ResponseWriter, r *http.Request) {
+		pool.AddRemote(r.PathValue("host"))
+	})
+
+	debugMux.HandleFunc("/debug/pprof/", pprof.Index)
+	debugMux.HandleFunc("/debug/pprof/cmdline", pprof.Cmdline)
+	debugMux.HandleFunc("/debug/pprof/profile", pprof.Profile)
+	debugMux.HandleFunc("/debug/pprof/symbol", pprof.Symbol)
+	debugMux.HandleFunc("/debug/pprof/trace", pprof.Trace)
+	debugMux.Handle("/metrics", promhttp.Handler())
+	mux.HandleFunc("/healthz", func(w http.ResponseWriter, r *http.Request) {
+		// Grain pool health: simple capacity check (mirrors previous GrainHandler.IsHealthy)
+		grainCount, capacity := app.pool.LocalUsage()
+		if grainCount >= capacity {
+			w.WriteHeader(http.StatusInternalServerError)
+			w.Write([]byte("grain pool at capacity"))
+			return
+		}
+		if !pool.IsHealthy() {
+			w.WriteHeader(http.StatusInternalServerError)
+			w.Write([]byte("control plane not healthy"))
+			return
+		}
+		w.WriteHeader(http.StatusOK)
+		w.Write([]byte("ok"))
+	})
+	mux.HandleFunc("/readyz", func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(http.StatusOK)
+		w.Write([]byte("ok"))
+	})
+	mux.HandleFunc("/livez", func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(http.StatusOK)
+		w.Write([]byte("ok"))
+	})
+
+	mux.HandleFunc("/version", func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(http.StatusOK)
+		w.Write([]byte("1.0.0"))
+	})
+
+	mux.HandleFunc("/openapi.json", ServeEmbeddedOpenAPI)
+
+	srv := &http.Server{
+		Addr:         ":8080",
+		BaseContext:  func(net.Listener) context.Context { return ctx },
+		ReadTimeout:  10 * time.Second,
+		WriteTimeout: 20 * time.Second,
+		Handler:      otelhttp.NewHandler(mux, "/"),
+	}
+
+	defer func() {
+
+		fmt.Println("Shutting down due to signal")
+		otelShutdown(context.Background())
+		diskStorage.Close()
+		pool.Close()
+
+	}()
+
+	srvErr := make(chan error, 1)
+	go func() {
+		srvErr <- srv.ListenAndServe()
+	}()
+
+	log.Print("Server started at port 8080")
+
+	go http.ListenAndServe(":8081", debugMux)
+
+	select {
+	case err = <-srvErr:
+		// Error when starting HTTP server.
+		log.Fatalf("Unable to start server: %v", err)
+	case <-ctx.Done():
+		// Wait for first CTRL+C.
+		// Stop receiving signal notifications as soon as possible.
+		stop()
+	}
+
+}
+
+func triggerOrderCompleted(syncedServer *PoolServer, order *CheckoutOrder) error {
+	mutation := &messages.OrderCreated{
+		OrderId: order.ID,
+		Status:  order.Status,
+	}
+	cid, ok := cart.ParseCartId(order.MerchantReference1)
+	if !ok {
+		return fmt.Errorf("invalid cart id in order reference: %s", order.MerchantReference1)
+	}
+	_, applyErr := syncedServer.Apply(uint64(cid), mutation)
+
+	return applyErr
+}
+
+func confirmOrder(order *CheckoutOrder, orderHandler *AmqpOrderHandler) error {
+	orderToSend, err := json.Marshal(order)
+	if err != nil {
+		return err
+	}
+
+	err = orderHandler.OrderCompleted(orderToSend)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}

cmd/cart/openapi.json

@@ -0,0 +1,677 @@
+{
+  "openapi": "3.0.3",
+  "info": {
+    "title": "Cart Service API",
+    "description": "HTTP API for shopping cart operations (cookie-based or explicit id): retrieve cart, add/replace items, update quantity, manage deliveries.",
+    "version": "1.0.0"
+  },
+  "servers": [
+    {
+      "url": "https://cart.tornberg.me",
+      "description": "Production server"
+    },
+    {
+      "url": "http://localhost:8080",
+      "description": "Local development (cart API mounted under /cart)"
+    }
+  ],
+  "paths": {
+    "/cart/": {
+      "get": {
+        "summary": "Get (or create) current cart (cookie based)",
+        "description": "Returns the current cart. If no cartid cookie is present a new cart is created and Set-Cart-Id response header plus a Set-Cookie header are sent.",
+        "responses": {
+          "200": {
+            "description": "Cart retrieved",
+            "headers": {
+              "Set-Cart-Id": {
+                "description": "Returned when a new cart was created this request",
+                "schema": { "type": "string" }
+              },
+              "X-Pod-Name": {
+                "description": "Pod identifier serving the request",
+                "schema": { "type": "string" }
+              }
+            },
+            "content": {
+              "application/json": {
+                "schema": { "$ref": "#/components/schemas/CartGrain" }
+              }
+            }
+          },
+          "500": { "description": "Server error" }
+        }
+      },
+      "post": {
+        "summary": "Add single SKU (body)",
+        "description": "Adds (or increases quantity of) a single SKU using request body.",
+        "requestBody": {
+          "required": true,
+          "content": {
+            "application/json": {
+              "schema": { "$ref": "#/components/schemas/AddRequest" }
+            }
+          }
+        },
+        "responses": {
+          "200": {
+            "description": "Item added",
+            "content": {
+              "application/json": {
+                "schema": { "$ref": "#/components/schemas/CartGrain" }
+              }
+            }
+          },
+          "400": { "description": "Invalid request body" },
+          "500": { "description": "Server error" }
+        }
+      },
+      "put": {
+        "summary": "Change quantity of an item",
+        "requestBody": {
+          "required": true,
+          "content": {
+            "application/json": {
+              "schema": { "$ref": "#/components/schemas/ChangeQuantity" }
+            }
+          }
+        },
+        "responses": {
+          "200": {
+            "description": "Quantity updated",
+            "content": {
+              "application/json": {
+                "schema": { "$ref": "#/components/schemas/CartGrain" }
+              }
+            }
+          },
+          "400": { "description": "Invalid request body" },
+          "500": { "description": "Server error" }
+        }
+      },
+      "delete": {
+        "summary": "Clear cart cookie (logical cart reused only if referenced later)",
+        "description": "Removes the cartid cookie by expiring it. Does not mutate server-side cart state.",
+        "responses": {
+          "200": { "description": "Cookie cleared (empty body)" }
+        }
+      }
+    },
+    "/cart/add/{sku}": {
+      "get": {
+        "summary": "Add a SKU (path)",
+        "description": "Adds a single SKU with implicit quantity 1. Country inferred from Host header (-se / -no).",
+        "parameters": [{ "$ref": "#/components/parameters/SkuParam" }],
+        "responses": {
+          "200": {
+            "description": "Item added",
+            "content": {
+              "application/json": {
+                "schema": { "$ref": "#/components/schemas/CartGrain" }
+              }
+            }
+          },
+          "500": { "description": "Server error" }
+        }
+      }
+    },
+    "/cart/add": {
+      "post": {
+        "summary": "Add multiple items (append)",
+        "description": "Adds multiple items to the cart without clearing existing contents.",
+        "requestBody": {
+          "required": true,
+          "content": {
+            "application/json": {
+              "schema": { "$ref": "#/components/schemas/SetCartItems" }
+            }
+          }
+        },
+        "responses": {
+          "200": {
+            "description": "Items added",
+            "content": {
+              "application/json": {
+                "schema": { "$ref": "#/components/schemas/CartGrain" }
+              }
+            }
+          },
+          "400": { "description": "Invalid body" },
+          "500": { "description": "Server error" }
+        }
+      }
+    },
+    "/cart/set": {
+      "post": {
+        "summary": "Replace cart contents",
+        "description": "Clears the cart first, then adds the provided items (idempotent with respect to target set).",
+        "requestBody": {
+          "required": true,
+          "content": {
+            "application/json": {
+              "schema": { "$ref": "#/components/schemas/SetCartItems" }
+            }
+          }
+        },
+        "responses": {
+          "200": {
+            "description": "Cart replaced",
+            "content": {
+              "application/json": {
+                "schema": { "$ref": "#/components/schemas/CartGrain" }
+              }
+            }
+          },
+          "400": { "description": "Invalid body" },
+          "500": { "description": "Server error" }
+        }
+      }
+    },
+    "/cart/{itemId}": {
+      "delete": {
+        "summary": "Remove item by line id",
+        "parameters": [
+          {
+            "name": "itemId",
+            "in": "path",
+            "required": true,
+            "schema": { "type": "integer", "format": "int64", "minimum": 0 },
+            "description": "Internal cart line item identifier (not SKU)."
+          }
+        ],
+        "responses": {
+          "200": {
+            "description": "Item removed",
+            "content": {
+              "application/json": {
+                "schema": { "$ref": "#/components/schemas/CartGrain" }
+              }
+            }
+          },
+          "400": { "description": "Bad id" },
+          "500": { "description": "Server error" }
+        }
+      }
+    },
+    "/cart/delivery": {
+      "post": {
+        "summary": "Set (add) delivery",
+        "description": "Adds a delivery option referencing one or more line item ids.",
+        "requestBody": {
+          "required": true,
+          "content": {
+            "application/json": {
+              "schema": { "$ref": "#/components/schemas/SetDeliveryRequest" }
+            }
+          }
+        },
+        "responses": {
+          "200": {
+            "description": "Delivery added/updated",
+            "content": {
+              "application/json": {
+                "schema": { "$ref": "#/components/schemas/CartGrain" }
+              }
+            }
+          },
+          "400": { "description": "Invalid body" },
+          "500": { "description": "Server error" }
+        }
+      }
+    },
+    "/cart/delivery/{deliveryId}": {
+      "delete": {
+        "summary": "Remove delivery",
+        "parameters": [{ "$ref": "#/components/parameters/DeliveryIdParam" }],
+        "responses": {
+          "200": {
+            "description": "Delivery removed",
+            "content": {
+              "application/json": {
+                "schema": { "$ref": "#/components/schemas/CartGrain" }
+              }
+            }
+          },
+          "400": { "description": "Bad id" },
+          "500": { "description": "Server error" }
+        }
+      }
+    },
+    "/cart/delivery/{deliveryId}/pickupPoint": {
+      "put": {
+        "summary": "Set pickup point for delivery",
+        "parameters": [{ "$ref": "#/components/parameters/DeliveryIdParam" }],
+        "requestBody": {
+          "required": true,
+          "content": {
+            "application/json": {
+              "schema": { "$ref": "#/components/schemas/PickupPoint" }
+            }
+          }
+        },
+        "responses": {
+          "200": {
+            "description": "Pickup point set",
+            "content": {
+              "application/json": {
+                "schema": { "$ref": "#/components/schemas/CartGrain" }
+              }
+            }
+          },
+          "400": { "description": "Invalid body" },
+          "500": { "description": "Server error" }
+        }
+      }
+    },
+    "/cart/byid/{id}": {
+      "get": {
+        "summary": "Get cart by explicit id",
+        "parameters": [{ "$ref": "#/components/parameters/CartIdParam" }],
+        "responses": {
+          "200": {
+            "description": "Cart retrieved",
+            "content": {
+              "application/json": {
+                "schema": { "$ref": "#/components/schemas/CartGrain" }
+              }
+            }
+          },
+          "400": { "description": "Invalid id" },
+          "500": { "description": "Server error" }
+        }
+      },
+      "post": {
+        "summary": "Add single SKU (body) by cart id",
+        "parameters": [{ "$ref": "#/components/parameters/CartIdParam" }],
+        "requestBody": {
+          "required": true,
+          "content": {
+            "application/json": {
+              "schema": { "$ref": "#/components/schemas/AddRequest" }
+            }
+          }
+        },
+        "responses": {
+          "200": {
+            "description": "Item added",
+            "content": {
+              "application/json": {
+                "schema": { "$ref": "#/components/schemas/CartGrain" }
+              }
+            }
+          },
+          "400": { "description": "Invalid body" },
+          "500": { "description": "Server error" }
+        }
+      },
+      "put": {
+        "summary": "Change quantity (by id variant)",
+        "parameters": [{ "$ref": "#/components/parameters/CartIdParam" }],
+        "requestBody": {
+          "required": true,
+          "content": {
+            "application/json": {
+              "schema": { "$ref": "#/components/schemas/ChangeQuantity" }
+            }
+          }
+        },
+        "responses": {
+          "200": {
+            "description": "Quantity updated",
+            "content": {
+              "application/json": {
+                "schema": { "$ref": "#/components/schemas/CartGrain" }
+              }
+            }
+          },
+          "400": { "description": "Invalid body" },
+          "500": { "description": "Server error" }
+        }
+      }
+    },
+    "/cart/byid/{id}/add/{sku}": {
+      "get": {
+        "summary": "Add SKU (path) by explicit cart id",
+        "parameters": [
+          { "$ref": "#/components/parameters/CartIdParam" },
+          { "$ref": "#/components/parameters/SkuParam" }
+        ],
+        "responses": {
+          "200": {
+            "description": "Item added",
+            "content": {
+              "application/json": {
+                "schema": { "$ref": "#/components/schemas/CartGrain" }
+              }
+            }
+          },
+          "400": { "description": "Invalid id/sku" },
+          "500": { "description": "Server error" }
+        }
+      }
+    },
+    "/cart/byid/{id}/{itemId}": {
+      "delete": {
+        "summary": "Remove item (by id variant)",
+        "parameters": [
+          { "$ref": "#/components/parameters/CartIdParam" },
+          {
+            "name": "itemId",
+            "in": "path",
+            "required": true,
+            "schema": { "type": "integer", "format": "int64", "minimum": 0 }
+          }
+        ],
+        "responses": {
+          "200": {
+            "description": "Item removed",
+            "content": {
+              "application/json": {
+                "schema": { "$ref": "#/components/schemas/CartGrain" }
+              }
+            }
+          },
+          "400": { "description": "Invalid id" },
+          "500": { "description": "Server error" }
+        }
+      }
+    },
+    "/cart/byid/{id}/delivery": {
+      "post": {
+        "summary": "Set delivery (by id variant)",
+        "parameters": [{ "$ref": "#/components/parameters/CartIdParam" }],
+        "requestBody": {
+          "required": true,
+          "content": {
+            "application/json": {
+              "schema": { "$ref": "#/components/schemas/SetDeliveryRequest" }
+            }
+          }
+        },
+        "responses": {
+          "200": {
+            "description": "Delivery added/updated",
+            "content": {
+              "application/json": {
+                "schema": { "$ref": "#/components/schemas/CartGrain" }
+              }
+            }
+          },
+          "400": { "description": "Invalid body" },
+          "500": { "description": "Server error" }
+        }
+      }
+    },
+    "/cart/byid/{id}/delivery/{deliveryId}": {
+      "delete": {
+        "summary": "Remove delivery (by id variant)",
+        "parameters": [
+          { "$ref": "#/components/parameters/CartIdParam" },
+          { "$ref": "#/components/parameters/DeliveryIdParam" }
+        ],
+        "responses": {
+          "200": {
+            "description": "Delivery removed",
+            "content": {
+              "application/json": {
+                "schema": { "$ref": "#/components/schemas/CartGrain" }
+              }
+            }
+          },
+          "400": { "description": "Invalid ids" },
+          "500": { "description": "Server error" }
+        }
+      }
+    },
+    "/cart/byid/{id}/delivery/{deliveryId}/pickupPoint": {
+      "put": {
+        "summary": "Set pickup point (by id variant)",
+        "parameters": [
+          { "$ref": "#/components/parameters/CartIdParam" },
+          { "$ref": "#/components/parameters/DeliveryIdParam" }
+        ],
+        "requestBody": {
+          "required": true,
+          "content": {
+            "application/json": {
+              "schema": { "$ref": "#/components/schemas/PickupPoint" }
+            }
+          }
+        },
+        "responses": {
+          "200": {
+            "description": "Pickup point updated",
+            "content": {
+              "application/json": {
+                "schema": { "$ref": "#/components/schemas/CartGrain" }
+              }
+            }
+          },
+          "400": { "description": "Invalid body" },
+          "500": { "description": "Server error" }
+        }
+      }
+    },
+    "/healthz": {
+      "get": {
+        "summary": "Liveness & capacity probe",
+        "responses": {
+          "200": { "description": "Healthy" },
+          "500": { "description": "Unhealthy" }
+        }
+      }
+    },
+    "/readyz": {
+      "get": {
+        "summary": "Readiness probe",
+        "responses": {
+          "200": { "description": "Ready" }
+        }
+      }
+    },
+    "/livez": {
+      "get": {
+        "summary": "Liveness probe",
+        "responses": {
+          "200": { "description": "Alive" }
+        }
+      }
+    },
+    "/version": {
+      "get": {
+        "summary": "Service version",
+        "responses": {
+          "200": {
+            "description": "Version string",
+            "content": {
+              "text/plain": {
+                "schema": { "type": "string", "example": "1.0.0" }
+              }
+            }
+          }
+        }
+      }
+    }
+  },
+  "components": {
+    "parameters": {
+      "SkuParam": {
+        "name": "sku",
+        "in": "path",
+        "required": true,
+        "schema": { "type": "string" }
+      },
+      "CartIdParam": {
+        "name": "id",
+        "in": "path",
+        "required": true,
+        "description": "Base62 encoded cart id",
+        "schema": {
+          "type": "string",
+          "pattern": "^[0-9A-Za-z]+$",
+          "minLength": 1
+        }
+      },
+      "DeliveryIdParam": {
+        "name": "deliveryId",
+        "in": "path",
+        "required": true,
+        "schema": { "type": "integer", "format": "int64", "minimum": 0 }
+      }
+    },
+    "schemas": {
+      "CartGrain": {
+        "type": "object",
+        "description": "Cart aggregate (actor state)",
+        "properties": {
+          "id": {
+            "type": "string",
+            "description": "Cart id (base62 encoded uint64)"
+          },
+          "items": {
+            "type": "array",
+            "items": { "$ref": "#/components/schemas/CartItem" }
+          },
+          "totalPrice": { "type": "integer", "format": "int64" },
+          "totalTax": { "type": "integer", "format": "int64" },
+          "totalDiscount": { "type": "integer", "format": "int64" },
+          "deliveries": {
+            "type": "array",
+            "items": { "$ref": "#/components/schemas/CartDelivery" }
+          },
+          "processing": { "type": "boolean" },
+          "paymentInProgress": { "type": "boolean" },
+          "orderReference": { "type": "string" },
+          "paymentStatus": { "type": "string" }
+        },
+        "required": ["id", "items", "totalPrice", "totalTax", "totalDiscount"]
+      },
+      "CartItem": {
+        "type": "object",
+        "properties": {
+          "id": { "type": "integer" },
+          "itemId": { "type": "integer" },
+          "parentId": { "type": "integer" },
+          "sku": { "type": "string" },
+          "name": { "type": "string" },
+          "price": { "type": "integer", "format": "int64" },
+          "totalPrice": { "type": "integer", "format": "int64" },
+          "totalTax": { "type": "integer", "format": "int64" },
+          "orgPrice": { "type": "integer", "format": "int64" },
+          "stock": {
+            "type": "integer",
+            "description": "0=OutOfStock,1=LowStock,2=InStock"
+          },
+          "qty": { "type": "integer" },
+          "tax": { "type": "integer" },
+          "taxRate": { "type": "integer" },
+          "brand": { "type": "string" },
+          "category": { "type": "string" },
+          "category2": { "type": "string" },
+          "category3": { "type": "string" },
+          "category4": { "type": "string" },
+          "category5": { "type": "string" },
+          "disclaimer": { "type": "string" },
+          "sellerId": { "type": "string" },
+          "sellerName": { "type": "string" },
+          "type": { "type": "string", "description": "Article type" },
+          "image": { "type": "string" },
+          "outlet": { "type": "string", "nullable": true },
+          "storeId": { "type": "string", "nullable": true }
+        },
+        "required": ["id", "sku", "name", "price", "qty", "tax"]
+      },
+      "CartDelivery": {
+        "type": "object",
+        "properties": {
+          "id": { "type": "integer" },
+          "provider": { "type": "string" },
+          "price": { "type": "integer", "format": "int64" },
+          "items": {
+            "type": "array",
+            "items": { "type": "integer" }
+          },
+          "pickupPoint": { "$ref": "#/components/schemas/PickupPoint" }
+        },
+        "required": ["id", "provider", "price", "items"]
+      },
+      "PickupPoint": {
+        "type": "object",
+        "properties": {
+          "id": { "type": "string" },
+          "name": { "type": "string", "nullable": true },
+          "address": { "type": "string", "nullable": true },
+          "city": { "type": "string", "nullable": true },
+          "zip": { "type": "string", "nullable": true },
+          "country": { "type": "string", "nullable": true }
+        },
+        "required": ["id"]
+      },
+      "AddRequest": {
+        "type": "object",
+        "properties": {
+          "quantity": {
+            "type": "integer",
+            "format": "int32",
+            "minimum": 1,
+            "default": 1
+          },
+          "sku": { "type": "string" },
+          "country": {
+            "type": "string",
+            "description": "Two-letter country code (inferred if omitted)"
+          },
+          "storeId": { "type": "string", "nullable": true }
+        },
+        "required": ["sku"]
+      },
+      "ChangeQuantity": {
+        "type": "object",
+        "properties": {
+          "id": {
+            "type": "integer",
+            "format": "int64",
+            "description": "Cart line item id"
+          },
+          "quantity": { "type": "integer", "format": "int32", "minimum": 0 }
+        },
+        "required": ["id", "quantity"]
+      },
+      "Item": {
+        "type": "object",
+        "properties": {
+          "sku": { "type": "string" },
+          "quantity": { "type": "integer", "minimum": 1 },
+          "storeId": { "type": "string", "nullable": true }
+        },
+        "required": ["sku", "quantity"]
+      },
+      "SetCartItems": {
+        "type": "object",
+        "properties": {
+          "country": { "type": "string" },
+          "items": {
+            "type": "array",
+            "items": { "$ref": "#/components/schemas/Item" },
+            "minItems": 0
+          }
+        },
+        "required": ["items"]
+      },
+      "SetDeliveryRequest": {
+        "type": "object",
+        "properties": {
+          "provider": { "type": "string" },
+          "items": {
+            "type": "array",
+            "items": { "type": "integer", "format": "int64" },
+            "description": "Line item ids served by this delivery"
+          },
+          "pickupPoint": { "$ref": "#/components/schemas/PickupPoint" }
+        },
+        "required": ["provider", "items"]
+      }
+    }
+  },
+  "tags": [{ "name": "Cart" }, { "name": "Delivery" }, { "name": "System" }]
+}

cmd/cart/openapi_embed.go

@@ -0,0 +1,69 @@
+package main
+
+import (
+	"bytes"
+	"crypto/sha256"
+	_ "embed"
+	"encoding/hex"
+	"net/http"
+	"sync"
+)
+
+// openapi_embed.go: Provides embedded OpenAPI spec and helper to mount handler.
+
+//go:embed openapi.json
+var openapiJSON []byte
+
+var (
+	openapiOnce sync.Once
+	openapiETag string
+)
+
+// initOpenAPIMetadata computes immutable metadata for the embedded spec.
+func initOpenAPIMetadata() {
+	sum := sha256.Sum256(openapiJSON)
+	openapiETag = `W/"` + hex.EncodeToString(sum[:8]) + `"` // weak ETag with first 8 bytes
+}
+
+// ServeEmbeddedOpenAPI serves the embedded OpenAPI JSON spec at /openapi.json.
+// It supports GET and HEAD and implements basic ETag caching.
+func ServeEmbeddedOpenAPI(w http.ResponseWriter, r *http.Request) {
+	if r.Method != http.MethodGet && r.Method != http.MethodHead {
+		w.Header().Set("Allow", "GET, HEAD")
+		http.Error(w, "method not allowed", http.StatusMethodNotAllowed)
+		return
+	}
+
+	openapiOnce.Do(initOpenAPIMetadata)
+
+	w.Header().Set("Content-Type", "application/json; charset=utf-8")
+	w.Header().Set("Cache-Control", "no-cache")
+	w.Header().Set("Access-Control-Allow-Origin", "*")
+	w.Header().Set("ETag", openapiETag)
+
+	if match := r.Header.Get("If-None-Match"); match != "" {
+		if bytes.Contains([]byte(match), []byte(openapiETag)) {
+			w.WriteHeader(http.StatusNotModified)
+			return
+		}
+	}
+
+	if r.Method == http.MethodHead {
+		w.WriteHeader(http.StatusOK)
+		return
+	}
+
+	w.WriteHeader(http.StatusOK)
+	_, _ = w.Write(openapiJSON)
+}
+
+// Optional: function to access raw spec bytes programmatically.
+func OpenAPISpecBytes() []byte {
+	return openapiJSON
+}
+
+// Optional: function to access current ETag.
+func OpenAPIETag() string {
+	openapiOnce.Do(initOpenAPIMetadata)
+	return openapiETag
+}

cmd/cart/otel.go

@@ -0,0 +1,117 @@
+package main
+
+import (
+	"context"
+	"errors"
+	"time"
+
+	"go.opentelemetry.io/otel"
+	"go.opentelemetry.io/otel/exporters/otlp/otlplog/otlploggrpc"
+	"go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracegrpc"
+	"go.opentelemetry.io/otel/exporters/prometheus"
+	"go.opentelemetry.io/otel/log/global"
+	"go.opentelemetry.io/otel/propagation"
+	"go.opentelemetry.io/otel/sdk/log"
+	"go.opentelemetry.io/otel/sdk/metric"
+	"go.opentelemetry.io/otel/sdk/trace"
+)
+
+// setupOTelSDK bootstraps the OpenTelemetry pipeline.
+// If it does not return an error, make sure to call shutdown for proper cleanup.
+func setupOTelSDK(ctx context.Context) (func(context.Context) error, error) {
+	var shutdownFuncs []func(context.Context) error
+	var err error
+
+	// shutdown calls cleanup functions registered via shutdownFuncs.
+	// The errors from the calls are joined.
+	// Each registered cleanup will be invoked once.
+	shutdown := func(ctx context.Context) error {
+		var err error
+		for _, fn := range shutdownFuncs {
+			err = errors.Join(err, fn(ctx))
+		}
+		shutdownFuncs = nil
+		return err
+	}
+
+	// handleErr calls shutdown for cleanup and makes sure that all errors are returned.
+	handleErr := func(inErr error) {
+		err = errors.Join(inErr, shutdown(ctx))
+	}
+
+	// Set up propagator.
+	prop := newPropagator()
+	otel.SetTextMapPropagator(prop)
+
+	// Set up trace provider.
+	tracerProvider, err := newTracerProvider()
+	if err != nil {
+		handleErr(err)
+		return shutdown, err
+	}
+	shutdownFuncs = append(shutdownFuncs, tracerProvider.Shutdown)
+	otel.SetTracerProvider(tracerProvider)
+
+	// Set up meter provider.
+	meterProvider, err := newMeterProvider()
+	if err != nil {
+		handleErr(err)
+		return shutdown, err
+	}
+	shutdownFuncs = append(shutdownFuncs, meterProvider.Shutdown)
+	otel.SetMeterProvider(meterProvider)
+
+	// Set up logger provider.
+	loggerProvider, err := newLoggerProvider()
+	if err != nil {
+		handleErr(err)
+		return shutdown, err
+	}
+	shutdownFuncs = append(shutdownFuncs, loggerProvider.Shutdown)
+	global.SetLoggerProvider(loggerProvider)
+
+	return shutdown, err
+}
+
+func newPropagator() propagation.TextMapPropagator {
+	return propagation.NewCompositeTextMapPropagator(
+		propagation.TraceContext{},
+		propagation.Baggage{},
+	)
+}
+
+func newTracerProvider() (*trace.TracerProvider, error) {
+	traceExporter, err := otlptracegrpc.New(context.Background())
+	if err != nil {
+		return nil, err
+	}
+
+	tracerProvider := trace.NewTracerProvider(
+		trace.WithBatcher(traceExporter,
+			// Default is 5s. Set to 1s for demonstrative purposes.
+			trace.WithBatchTimeout(time.Second)),
+	)
+	return tracerProvider, nil
+}
+
+func newMeterProvider() (*metric.MeterProvider, error) {
+	exporter, err := prometheus.New()
+	if err != nil {
+		return nil, err
+	}
+
+	provider := metric.NewMeterProvider(metric.WithReader(exporter))
+	return provider, nil
+}
+
+func newLoggerProvider() (*log.LoggerProvider, error) {
+	logExporter, err := otlploggrpc.New(context.Background())
+	if err != nil {
+		return nil, err
+	}
+
+	loggerProvider := log.NewLoggerProvider(
+		log.WithProcessor(log.NewBatchProcessor(logExporter)),
+	)
+	return loggerProvider, nil
+}

cmd/cart/pool-server.go

@@ -0,0 +1,613 @@
+package main
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"log"
+	"net/http"
+	"strconv"
+	"sync"
+	"time"
+
+	"git.tornberg.me/go-cart-actor/pkg/actor"
+	"git.tornberg.me/go-cart-actor/pkg/cart"
+	messages "git.tornberg.me/go-cart-actor/pkg/messages"
+	"git.tornberg.me/go-cart-actor/pkg/voucher"
+	"github.com/gogo/protobuf/proto"
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/client_golang/prometheus/promauto"
+	"go.opentelemetry.io/contrib/bridges/otelslog"
+	"go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp"
+	"go.opentelemetry.io/otel"
+	"go.opentelemetry.io/otel/attribute"
+)
+
+var (
+	grainMutations = promauto.NewCounter(prometheus.CounterOpts{
+		Name: "cart_grain_mutations_total",
+		Help: "The total number of mutations",
+	})
+	grainLookups = promauto.NewCounter(prometheus.CounterOpts{
+		Name: "cart_grain_lookups_total",
+		Help: "The total number of lookups",
+	})
+)
+
+type PoolServer struct {
+	actor.GrainPool[*cart.CartGrain]
+	pod_name     string
+	klarnaClient *KlarnaClient
+}
+
+func NewPoolServer(pool actor.GrainPool[*cart.CartGrain], pod_name string, klarnaClient *KlarnaClient) *PoolServer {
+	return &PoolServer{
+		GrainPool:    pool,
+		pod_name:     pod_name,
+		klarnaClient: klarnaClient,
+	}
+}
+
+func (s *PoolServer) ApplyLocal(id cart.CartId, mutation ...proto.Message) (*actor.MutationResult[*cart.CartGrain], error) {
+	return s.Apply(uint64(id), mutation...)
+}
+
+func (s *PoolServer) GetCartHandler(w http.ResponseWriter, r *http.Request, id cart.CartId) error {
+	grain, err := s.Get(uint64(id))
+	if err != nil {
+		return err
+	}
+
+	return s.WriteResult(w, grain)
+}
+
+func (s *PoolServer) AddSkuToCartHandler(w http.ResponseWriter, r *http.Request, id cart.CartId) error {
+	sku := r.PathValue("sku")
+	msg, err := GetItemAddMessage(sku, 1, getCountryFromHost(r.Host), nil)
+	if err != nil {
+		return err
+	}
+	data, err := s.ApplyLocal(id, msg)
+	if err != nil {
+		return err
+	}
+	grainMutations.Add(float64(len(data.Mutations)))
+	return s.WriteResult(w, data)
+}
+
+func (s *PoolServer) WriteResult(w http.ResponseWriter, result any) error {
+	w.Header().Set("Content-Type", "application/json")
+	w.Header().Set("Cache-Control", "no-cache")
+	w.Header().Set("Access-Control-Allow-Origin", "*")
+	w.Header().Set("X-Pod-Name", s.pod_name)
+	if result == nil {
+
+		w.WriteHeader(http.StatusInternalServerError)
+
+		return nil
+	}
+	w.WriteHeader(http.StatusOK)
+	enc := json.NewEncoder(w)
+	err := enc.Encode(result)
+	return err
+}
+
+func (s *PoolServer) DeleteItemHandler(w http.ResponseWriter, r *http.Request, id cart.CartId) error {
+
+	itemIdString := r.PathValue("itemId")
+	itemId, err := strconv.ParseInt(itemIdString, 10, 64)
+	if err != nil {
+		return err
+	}
+	data, err := s.ApplyLocal(id, &messages.RemoveItem{Id: uint32(itemId)})
+	if err != nil {
+		return err
+	}
+	return s.WriteResult(w, data)
+}
+
+type SetDeliveryRequest struct {
+	Provider    string                `json:"provider"`
+	Items       []uint32              `json:"items"`
+	PickupPoint *messages.PickupPoint `json:"pickupPoint,omitempty"`
+}
+
+func (s *PoolServer) SetDeliveryHandler(w http.ResponseWriter, r *http.Request, id cart.CartId) error {
+
+	delivery := SetDeliveryRequest{}
+	err := json.NewDecoder(r.Body).Decode(&delivery)
+	if err != nil {
+		return err
+	}
+	data, err := s.ApplyLocal(id, &messages.SetDelivery{
+		Provider:    delivery.Provider,
+		Items:       delivery.Items,
+		PickupPoint: delivery.PickupPoint,
+	})
+	if err != nil {
+		return err
+	}
+	return s.WriteResult(w, data)
+}
+
+func (s *PoolServer) SetPickupPointHandler(w http.ResponseWriter, r *http.Request, id cart.CartId) error {
+
+	deliveryIdString := r.PathValue("deliveryId")
+	deliveryId, err := strconv.ParseInt(deliveryIdString, 10, 64)
+	if err != nil {
+		return err
+	}
+	pickupPoint := messages.PickupPoint{}
+	err = json.NewDecoder(r.Body).Decode(&pickupPoint)
+	if err != nil {
+		return err
+	}
+	reply, err := s.ApplyLocal(id, &messages.SetPickupPoint{
+		DeliveryId: uint32(deliveryId),
+		Id:         pickupPoint.Id,
+		Name:       pickupPoint.Name,
+		Address:    pickupPoint.Address,
+		City:       pickupPoint.City,
+		Zip:        pickupPoint.Zip,
+		Country:    pickupPoint.Country,
+	})
+	if err != nil {
+		return err
+	}
+	return s.WriteResult(w, reply)
+}
+
+func (s *PoolServer) RemoveDeliveryHandler(w http.ResponseWriter, r *http.Request, id cart.CartId) error {
+
+	deliveryIdString := r.PathValue("deliveryId")
+	deliveryId, err := strconv.Atoi(deliveryIdString)
+	if err != nil {
+		return err
+	}
+	reply, err := s.ApplyLocal(id, &messages.RemoveDelivery{Id: uint32(deliveryId)})
+	if err != nil {
+		return err
+	}
+	return s.WriteResult(w, reply)
+}
+
+func (s *PoolServer) QuantityChangeHandler(w http.ResponseWriter, r *http.Request, id cart.CartId) error {
+	changeQuantity := messages.ChangeQuantity{}
+	err := json.NewDecoder(r.Body).Decode(&changeQuantity)
+	if err != nil {
+		return err
+	}
+	reply, err := s.ApplyLocal(id, &changeQuantity)
+	if err != nil {
+		return err
+	}
+	return s.WriteResult(w, reply)
+}
+
+type Item struct {
+	Sku      string  `json:"sku"`
+	Quantity int     `json:"quantity"`
+	StoreId  *string `json:"storeId,omitempty"`
+}
+
+type SetCartItems struct {
+	Country string `json:"country"`
+	Items   []Item `json:"items"`
+}
+
+func getMultipleAddMessages(items []Item, country string) []proto.Message {
+	wg := sync.WaitGroup{}
+	mu := sync.Mutex{}
+	msgs := make([]proto.Message, 0, len(items))
+	for _, itm := range items {
+		wg.Go(
+			func() {
+				msg, err := GetItemAddMessage(itm.Sku, itm.Quantity, country, itm.StoreId)
+				if err != nil {
+					log.Printf("error adding item %s: %v", itm.Sku, err)
+					return
+				}
+				mu.Lock()
+				msgs = append(msgs, msg)
+				mu.Unlock()
+			})
+	}
+	wg.Wait()
+	return msgs
+}
+
+func (s *PoolServer) SetCartItemsHandler(w http.ResponseWriter, r *http.Request, id cart.CartId) error {
+	setCartItems := SetCartItems{}
+	err := json.NewDecoder(r.Body).Decode(&setCartItems)
+	if err != nil {
+		return err
+	}
+
+	msgs := make([]proto.Message, 0, len(setCartItems.Items)+1)
+	msgs = append(msgs, &messages.ClearCartRequest{})
+	msgs = append(msgs, getMultipleAddMessages(setCartItems.Items, setCartItems.Country)...)
+
+	reply, err := s.ApplyLocal(id, msgs...)
+	if err != nil {
+		return err
+	}
+	return s.WriteResult(w, reply)
+}
+
+func (s *PoolServer) AddMultipleItemHandler(w http.ResponseWriter, r *http.Request, id cart.CartId) error {
+	setCartItems := SetCartItems{}
+	err := json.NewDecoder(r.Body).Decode(&setCartItems)
+	if err != nil {
+		return err
+	}
+
+	reply, err := s.ApplyLocal(id, getMultipleAddMessages(setCartItems.Items, setCartItems.Country)...)
+	if err != nil {
+		return err
+	}
+	return s.WriteResult(w, reply)
+}
+
+type AddRequest struct {
+	Sku      string  `json:"sku"`
+	Quantity int32   `json:"quantity"`
+	Country  string  `json:"country"`
+	StoreId  *string `json:"storeId"`
+}
+
+func (s *PoolServer) AddSkuRequestHandler(w http.ResponseWriter, r *http.Request, id cart.CartId) error {
+	addRequest := AddRequest{Quantity: 1}
+	err := json.NewDecoder(r.Body).Decode(&addRequest)
+	if err != nil {
+		return err
+	}
+	msg, err := GetItemAddMessage(addRequest.Sku, int(addRequest.Quantity), addRequest.Country, addRequest.StoreId)
+	if err != nil {
+		return err
+	}
+	reply, err := s.ApplyLocal(id, msg)
+	if err != nil {
+		return err
+	}
+
+	return s.WriteResult(w, reply)
+}
+
+// func (s *PoolServer) HandleConfirmation(w http.ResponseWriter, r *http.Request, id CartId) error {
+// 	orderId := r.PathValue("orderId")
+// 	if orderId == "" {
+// 		return fmt.Errorf("orderId is empty")
+// 	}
+// 	order, err := KlarnaInstance.GetOrder(orderId)
+
+// 	if err != nil {
+// 		return err
+// 	}
+
+// 	w.Header().Set("Content-Type", "application/json")
+// 	w.Header().Set("X-Pod-Name", s.pod_name)
+// 	w.Header().Set("Cache-Control", "no-cache")
+// 	w.Header().Set("Access-Control-Allow-Origin", "*")
+// 	w.WriteHeader(http.StatusOK)
+// 	return json.NewEncoder(w).Encode(order)
+// }
+
+func getCurrency(country string) string {
+	if country == "no" {
+		return "NOK"
+	}
+	return "SEK"
+}
+
+func getLocale(country string) string {
+	if country == "no" {
+		return "nb-no"
+	}
+	return "sv-se"
+}
+
+func (s *PoolServer) CreateOrUpdateCheckout(host string, id cart.CartId) (*CheckoutOrder, error) {
+	country := getCountryFromHost(host)
+	meta := &CheckoutMeta{
+		Terms:        fmt.Sprintf("https://%s/terms", host),
+		Checkout:     fmt.Sprintf("https://%s/checkout?order_id={checkout.order.id}", host),
+		Confirmation: fmt.Sprintf("https://%s/confirmation/{checkout.order.id}", host),
+		Validation:   fmt.Sprintf("https://%s/validate", host),
+		Push:         fmt.Sprintf("https://%s/push?order_id={checkout.order.id}", host),
+		Country:      country,
+		Currency:     getCurrency(country),
+		Locale:       getLocale(country),
+	}
+
+	// Get current grain state (may be local or remote)
+	grain, err := s.Get(uint64(id))
+	if err != nil {
+		return nil, err
+	}
+
+	// Build pure checkout payload
+	payload, _, err := BuildCheckoutOrderPayload(grain, meta)
+	if err != nil {
+		return nil, err
+	}
+
+	if grain.OrderReference != "" {
+		return s.klarnaClient.UpdateOrder(grain.OrderReference, bytes.NewReader(payload))
+	} else {
+		return s.klarnaClient.CreateOrder(bytes.NewReader(payload))
+	}
+}
+
+func (s *PoolServer) ApplyCheckoutStarted(klarnaOrder *CheckoutOrder, id cart.CartId) (*actor.MutationResult[*cart.CartGrain], error) {
+	// Persist initialization state via mutation (best-effort)
+	return s.ApplyLocal(id, &messages.InitializeCheckout{
+		OrderId:           klarnaOrder.ID,
+		Status:            klarnaOrder.Status,
+		PaymentInProgress: true,
+	})
+}
+
+// func (s *PoolServer) HandleCheckout(w http.ResponseWriter, r *http.Request, id CartId) error {
+// 	klarnaOrder, err := s.CreateOrUpdateCheckout(r.Host, id)
+// 	if err != nil {
+// 		return err
+// 	}
+
+// 	s.ApplyCheckoutStarted(klarnaOrder, id)
+
+// 	w.Header().Set("Content-Type", "application/json")
+// 	return json.NewEncoder(w).Encode(klarnaOrder)
+// }
+//
+
+func CookieCartIdHandler(fn func(cartId cart.CartId, w http.ResponseWriter, r *http.Request) error) func(w http.ResponseWriter, r *http.Request) {
+	return func(w http.ResponseWriter, r *http.Request) {
+		var id cart.CartId
+		cookie, err := r.Cookie("cartid")
+		if err != nil || cookie.Value == "" {
+			id = cart.MustNewCartId()
+			http.SetCookie(w, &http.Cookie{
+				Name:     "cartid",
+				Value:    id.String(),
+				Secure:   r.TLS != nil,
+				HttpOnly: true,
+				Path:     "/",
+				Expires:  time.Now().AddDate(0, 0, 14),
+				SameSite: http.SameSiteLaxMode,
+			})
+			w.Header().Set("Set-Cart-Id", id.String())
+		} else {
+			parsed, ok := cart.ParseCartId(cookie.Value)
+			if !ok {
+				id = cart.MustNewCartId()
+				http.SetCookie(w, &http.Cookie{
+					Name:     "cartid",
+					Value:    id.String(),
+					Secure:   r.TLS != nil,
+					HttpOnly: true,
+					Path:     "/",
+					Expires:  time.Now().AddDate(0, 0, 14),
+					SameSite: http.SameSiteLaxMode,
+				})
+				w.Header().Set("Set-Cart-Id", id.String())
+			} else {
+				id = parsed
+			}
+		}
+
+		err = fn(id, w, r)
+		if err != nil {
+			log.Printf("Server error, not remote error: %v\n", err)
+			w.WriteHeader(http.StatusInternalServerError)
+			w.Write([]byte(err.Error()))
+		}
+
+	}
+}
+
+// Removed leftover legacy block after CookieCartIdHandler (obsolete code referencing cid/legacy)
+
+func (s *PoolServer) RemoveCartCookie(w http.ResponseWriter, r *http.Request, cartId cart.CartId) error {
+	// Clear cart cookie (breaking change: do not issue a new legacy id here)
+	http.SetCookie(w, &http.Cookie{
+		Name:     "cartid",
+		Value:    "",
+		Path:     "/",
+		Secure:   r.TLS != nil,
+		HttpOnly: true,
+		Expires:  time.Unix(0, 0),
+		SameSite: http.SameSiteLaxMode,
+	})
+	w.WriteHeader(http.StatusOK)
+	return nil
+}
+
+func CartIdHandler(fn func(cartId cart.CartId, w http.ResponseWriter, r *http.Request) error) func(w http.ResponseWriter, r *http.Request) {
+	return func(w http.ResponseWriter, r *http.Request) {
+		var id cart.CartId
+		raw := r.PathValue("id")
+		// If no id supplied, generate a new one
+		if raw == "" {
+			id := cart.MustNewCartId()
+			w.Header().Set("Set-Cart-Id", id.String())
+		} else {
+			// Parse base62 cart id
+			if parsedId, ok := cart.ParseCartId(raw); !ok {
+				w.WriteHeader(http.StatusBadRequest)
+				w.Write([]byte("cart id is invalid"))
+				return
+			} else {
+				id = parsedId
+			}
+		}
+
+		err := fn(id, w, r)
+		if err != nil {
+			log.Printf("Server error, not remote error: %v\n", err)
+			w.WriteHeader(http.StatusInternalServerError)
+			w.Write([]byte(err.Error()))
+		}
+	}
+}
+
+func (s *PoolServer) ProxyHandler(fn func(w http.ResponseWriter, r *http.Request, cartId cart.CartId) error) func(cartId cart.CartId, w http.ResponseWriter, r *http.Request) error {
+	return func(cartId cart.CartId, w http.ResponseWriter, r *http.Request) error {
+		if ownerHost, ok := s.OwnerHost(uint64(cartId)); ok {
+			_, span := tracer.Start(r.Context(), "proxy")
+			defer span.End()
+
+			span.SetAttributes(attribute.String("other host", ownerHost.Name()))
+			handled, err := ownerHost.Proxy(uint64(cartId), w, r)
+
+			grainLookups.Inc()
+			if err == nil && handled {
+				return nil
+			}
+		}
+		_, span := tracer.Start(r.Context(), "own")
+		defer span.End()
+		return fn(w, r, cartId)
+
+	}
+}
+
+var (
+	tracer = otel.Tracer(name)
+
+	// meter   = otel.Meter(name)
+	logger = otelslog.NewLogger(name)
+
+// rollCnt metric.Int64Counter
+)
+
+type AddVoucherRequest struct {
+	VoucherCode string `json:"code"`
+}
+
+func (s *PoolServer) AddVoucherHandler(w http.ResponseWriter, r *http.Request, cartId cart.CartId) error {
+	data := &AddVoucherRequest{}
+	json.NewDecoder(r.Body).Decode(data)
+	v := voucher.Service{}
+	msg, err := v.GetVoucher(data.VoucherCode)
+	if err != nil {
+		s.ApplyLocal(cartId, &messages.PreConditionFailed{
+			Operation: "AddVoucher",
+			Error:     err.Error(),
+		})
+		w.WriteHeader(http.StatusInternalServerError)
+		w.Write([]byte(err.Error()))
+		return err
+	}
+	reply, err := s.ApplyLocal(cartId, msg)
+	if err != nil {
+		w.WriteHeader(http.StatusInternalServerError)
+		w.Write([]byte(err.Error()))
+		return err
+	}
+	s.WriteResult(w, reply)
+	return nil
+}
+
+func (s *PoolServer) SubscriptionDetailsHandler(w http.ResponseWriter, r *http.Request, cartId cart.CartId) error {
+	data := &messages.UpsertSubscriptionDetails{}
+	err := json.NewDecoder(r.Body).Decode(data)
+	if err != nil {
+		w.WriteHeader(http.StatusInternalServerError)
+		w.Write([]byte(err.Error()))
+		return err
+	}
+	reply, err := s.ApplyLocal(cartId, data)
+	if err != nil {
+		w.WriteHeader(http.StatusInternalServerError)
+		w.Write([]byte(err.Error()))
+		return err
+	}
+	s.WriteResult(w, reply)
+	return nil
+}
+
+func (s *PoolServer) CheckoutHandler(fn func(order *CheckoutOrder, w http.ResponseWriter) error) func(w http.ResponseWriter, r *http.Request) {
+	return CookieCartIdHandler(s.ProxyHandler(func(w http.ResponseWriter, r *http.Request, cartId cart.CartId) error {
+		orderId := r.URL.Query().Get("order_id")
+		if orderId == "" {
+			order, err := s.CreateOrUpdateCheckout(r.Host, cartId)
+			if err != nil {
+				return err
+			}
+			s.ApplyCheckoutStarted(order, cartId)
+			return fn(order, w)
+		}
+		order, err := s.klarnaClient.GetOrder(orderId)
+		if err != nil {
+			return err
+		}
+		return fn(order, w)
+	}))
+}
+
+func (s *PoolServer) RemoveVoucherHandler(w http.ResponseWriter, r *http.Request, cartId cart.CartId) error {
+
+	idStr := r.PathValue("voucherId")
+	id, err := strconv.ParseInt(idStr, 10, 64)
+	if err != nil {
+		w.WriteHeader(http.StatusInternalServerError)
+		w.Write([]byte(err.Error()))
+		return err
+	}
+	reply, err := s.ApplyLocal(cartId, &messages.RemoveVoucher{Id: uint32(id)})
+	if err != nil {
+		w.WriteHeader(http.StatusInternalServerError)
+		w.Write([]byte(err.Error()))
+		return err
+	}
+	s.WriteResult(w, reply)
+	return nil
+}
+
+func (s *PoolServer) Serve(mux *http.ServeMux) {
+
+	mux.HandleFunc("OPTIONS /", func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Access-Control-Allow-Origin", "*")
+		w.Header().Set("Access-Control-Allow-Methods", "GET, PUT, POST, DELETE")
+		w.Header().Set("Access-Control-Allow-Headers", "Content-Type")
+		w.WriteHeader(http.StatusOK)
+	})
+
+	handleFunc := func(pattern string, handlerFunc func(http.ResponseWriter, *http.Request)) {
+		// Configure the "http.route" for the HTTP instrumentation.
+		handler := otelhttp.WithRouteTag(pattern, http.HandlerFunc(handlerFunc))
+		mux.Handle(pattern, handler)
+	}
+
+	handleFunc("GET /cart", CookieCartIdHandler(s.ProxyHandler(s.GetCartHandler)))
+	handleFunc("GET /cart/add/{sku}", CookieCartIdHandler(s.ProxyHandler(s.AddSkuToCartHandler)))
+	handleFunc("POST /cart/add", CookieCartIdHandler(s.ProxyHandler(s.AddMultipleItemHandler)))
+	handleFunc("POST /cart", CookieCartIdHandler(s.ProxyHandler(s.AddSkuRequestHandler)))
+	handleFunc("POST /cart/set", CookieCartIdHandler(s.ProxyHandler(s.SetCartItemsHandler)))
+	handleFunc("DELETE /cart/{itemId}", CookieCartIdHandler(s.ProxyHandler(s.DeleteItemHandler)))
+	handleFunc("PUT /cart", CookieCartIdHandler(s.ProxyHandler(s.QuantityChangeHandler)))
+	handleFunc("DELETE /cart", CookieCartIdHandler(s.ProxyHandler(s.RemoveCartCookie)))
+	handleFunc("POST /cart/delivery", CookieCartIdHandler(s.ProxyHandler(s.SetDeliveryHandler)))
+	handleFunc("DELETE /cart/delivery/{deliveryId}", CookieCartIdHandler(s.ProxyHandler(s.RemoveDeliveryHandler)))
+	handleFunc("PUT /cart/delivery/{deliveryId}/pickupPoint", CookieCartIdHandler(s.ProxyHandler(s.SetPickupPointHandler)))
+	handleFunc("PUT /cart/voucher", CookieCartIdHandler(s.ProxyHandler(s.AddVoucherHandler)))
+	handleFunc("PUT /cart/subscription-details", CookieCartIdHandler(s.ProxyHandler(s.SubscriptionDetailsHandler)))
+	handleFunc("DELETE /cart/voucher/{voucherId}", CookieCartIdHandler(s.ProxyHandler(s.RemoveVoucherHandler)))
+
+	//mux.HandleFunc("GET /cart/checkout", CookieCartIdHandler(s.ProxyHandler(s.HandleCheckout)))
+	//mux.HandleFunc("GET /cart/confirmation/{orderId}", CookieCartIdHandler(s.ProxyHandler(s.HandleConfirmation)))
+
+	handleFunc("GET /cart/byid/{id}", CartIdHandler(s.ProxyHandler(s.GetCartHandler)))
+	handleFunc("GET /cart/byid/{id}/add/{sku}", CartIdHandler(s.ProxyHandler(s.AddSkuToCartHandler)))
+	handleFunc("POST /cart/byid/{id}", CartIdHandler(s.ProxyHandler(s.AddSkuRequestHandler)))
+	handleFunc("DELETE /cart/byid/{id}/{itemId}", CartIdHandler(s.ProxyHandler(s.DeleteItemHandler)))
+	handleFunc("PUT /cart/byid/{id}", CartIdHandler(s.ProxyHandler(s.QuantityChangeHandler)))
+	handleFunc("POST /cart/byid/{id}/delivery", CartIdHandler(s.ProxyHandler(s.SetDeliveryHandler)))
+	handleFunc("DELETE /cart/byid/{id}/delivery/{deliveryId}", CartIdHandler(s.ProxyHandler(s.RemoveDeliveryHandler)))
+	handleFunc("PUT /cart/byid/{id}/delivery/{deliveryId}/pickupPoint", CartIdHandler(s.ProxyHandler(s.SetPickupPointHandler)))
+	handleFunc("PUT /cart/byid/{id}/voucher", CookieCartIdHandler(s.ProxyHandler(s.AddVoucherHandler)))
+	handleFunc("DELETE /cart/byid/{id}/voucher/{voucherId}", CookieCartIdHandler(s.ProxyHandler(s.RemoveVoucherHandler)))
+	//mux.HandleFunc("GET /cart/byid/{id}/checkout", CartIdHandler(s.ProxyHandler(s.HandleCheckout)))
+	//mux.HandleFunc("GET /cart/byid/{id}/confirmation", CartIdHandler(s.ProxyHandler(s.HandleConfirmation)))
+
+}

cmd/cart/product-fetcher.go

@@ -0,0 +1,140 @@
+package main
+
+import (
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"strconv"
+	"strings"
+
+	"git.tornberg.me/go-cart-actor/pkg/cart"
+	messages "git.tornberg.me/go-cart-actor/pkg/messages"
+	"github.com/matst80/slask-finder/pkg/index"
+)
+
+// TODO make this configurable
+func getBaseUrl(country string) string {
+	// if country == "se" {
+	// 	return "http://s10n-se:8080"
+	// }
+	if country == "no" {
+		return "http://s10n-no.s10n:8080"
+	}
+	if country == "se" {
+		return "http://s10n-se.s10n:8080"
+	}
+	return "http://localhost:8082"
+}
+
+func FetchItem(sku string, country string) (*index.DataItem, error) {
+	baseUrl := getBaseUrl(country)
+	res, err := http.Get(fmt.Sprintf("%s/api/by-sku/%s", baseUrl, sku))
+	if err != nil {
+		return nil, err
+	}
+	defer res.Body.Close()
+	var item index.DataItem
+	err = json.NewDecoder(res.Body).Decode(&item)
+	return &item, err
+}
+
+func GetItemAddMessage(sku string, qty int, country string, storeId *string) (*messages.AddItem, error) {
+	item, err := FetchItem(sku, country)
+	if err != nil {
+		return nil, err
+	}
+	return ToItemAddMessage(item, storeId, qty, country)
+}
+
+func ToItemAddMessage(item *index.DataItem, storeId *string, qty int, country string) (*messages.AddItem, error) {
+	orgPrice, _ := getInt(item.GetNumberFieldValue(5)) // getInt(item.Fields[5])
+
+	price, err := getInt(item.GetNumberFieldValue(4)) //Fields[4]
+	if err != nil {
+		return nil, err
+	}
+
+	stock := cart.StockStatus(0)
+	centralStockValue, ok := item.GetStringFieldValue(3)
+	if storeId == nil {
+		if ok {
+			if !item.Buyable {
+				return nil, fmt.Errorf("item not available")
+			}
+			pureNumber := strings.Replace(centralStockValue, "+", "", -1)
+			if centralStock, err := strconv.ParseInt(pureNumber, 10, 64); err == nil {
+				stock = cart.StockStatus(centralStock)
+			}
+			if stock == cart.StockStatus(0) && item.SaleStatus == "TBD" {
+				return nil, fmt.Errorf("no items available")
+			}
+		}
+	} else {
+		if !item.BuyableInStore {
+			return nil, fmt.Errorf("item not available in store")
+		}
+		storeStock, ok := item.Stock.GetStock()[*storeId]
+		if ok {
+			stock = cart.StockStatus(storeStock)
+		}
+
+	}
+
+	articleType, _ := item.GetStringFieldValue(1)   //.Fields[1].(string)
+	outletGrade, ok := item.GetStringFieldValue(20) //.Fields[20].(string)
+	var outlet *string
+	if ok {
+		outlet = &outletGrade
+	}
+	sellerId, _ := item.GetStringFieldValue(24)  // .Fields[24].(string)
+	sellerName, _ := item.GetStringFieldValue(9) // .Fields[9].(string)
+
+	brand, _ := item.GetStringFieldValue(2)      //.Fields[2].(string)
+	category, _ := item.GetStringFieldValue(10)  //.Fields[10].(string)
+	category2, _ := item.GetStringFieldValue(11) //.Fields[11].(string)
+	category3, _ := item.GetStringFieldValue(12) //.Fields[12].(string)
+	category4, _ := item.GetStringFieldValue(13) //Fields[13].(string)
+	category5, _ := item.GetStringFieldValue(14) //.Fields[14].(string)
+
+	return &messages.AddItem{
+		ItemId:      uint32(item.Id),
+		Quantity:    int32(qty),
+		Price:       int64(price),
+		OrgPrice:    int64(orgPrice),
+		Sku:         item.GetSku(),
+		Name:        item.Title,
+		Image:       item.Img,
+		Stock:       int32(stock),
+		Brand:       brand,
+		Category:    category,
+		Category2:   category2,
+		Category3:   category3,
+		Category4:   category4,
+		Category5:   category5,
+		Tax:         getTax(articleType),
+		SellerId:    sellerId,
+		SellerName:  sellerName,
+		ArticleType: articleType,
+		Disclaimer:  item.Disclaimer,
+		Country:     country,
+		Outlet:      outlet,
+		StoreId:     storeId,
+		SaleStatus:  item.SaleStatus,
+	}, nil
+}
+
+func getTax(articleType string) int32 {
+	switch articleType {
+	case "ZDIE":
+		return 600
+	default:
+		return 2500
+	}
+}
+
+func getInt(data float64, ok bool) (int, error) {
+	if !ok {
+		return 0, fmt.Errorf("invalid type")
+	}
+	return int(data), nil
+}

cmd/inventory/main.go

@@ -0,0 +1,61 @@
+package main
+
+import (
+	"context"
+	"log"
+
+	"git.tornberg.me/go-cart-actor/pkg/inventory"
+	"github.com/redis/go-redis/v9"
+	"github.com/redis/go-redis/v9/maintnotifications"
+)
+
+func main() {
+	var ctx = context.Background()
+	rdb := redis.NewClient(&redis.Options{
+		Addr:     "10.10.3.18:6379",
+		Password: "slaskredis", // no password set
+		DB:       0,            // use default DB
+		MaintNotificationsConfig: &maintnotifications.Config{
+			Mode: maintnotifications.ModeDisabled,
+		},
+	})
+	s, err := inventory.NewRedisInventoryService(rdb, ctx)
+	if err != nil {
+		log.Fatalf("Unable to connect to inventory redis: %v", err)
+		return
+	}
+	rdb.Pipelined(ctx, func(p redis.Pipeliner) error {
+		s.UpdateInventory(p, "1", "1", 10)
+		s.UpdateInventory(p, "2", "2", 20)
+		s.UpdateInventory(p, "3", "3", 30)
+		s.UpdateInventory(p, "4", "4", 40)
+		return nil
+	})
+	err = s.ReserveInventory(
+		inventory.ReserveRequest{
+			SKU:        "1",
+			LocationID: "1",
+			Quantity:   3,
+		},
+		inventory.ReserveRequest{
+			SKU:        "2",
+			LocationID: "2",
+			Quantity:   15,
+		},
+		inventory.ReserveRequest{
+			SKU:        "3",
+			LocationID: "3",
+			Quantity:   25,
+		},
+	)
+	if err != nil {
+		log.Printf("Unable to reserve inventory: %v", err)
+	}
+	v, err := s.GetInventory("1", "1")
+	if err != nil {
+		log.Printf("Unable to get inventory: %v", err)
+		return
+	}
+	log.Printf("Inventory after reservation: %v", v)
+
+}

deployment/deployment.yaml

@@ -9,13 +9,101 @@ type: Opaque
 ---
 apiVersion: apps/v1
 kind: Deployment
+metadata:
+  labels:
+    app: cart-backoffice
+    arch: amd64
+  name: cart-backoffice-x86
+spec:
+  replicas: 1
+  selector:
+    matchLabels:
+      app: cart-backoffice
+      arch: amd64
+  template:
+    metadata:
+      labels:
+        app: cart-backoffice
+        arch: amd64
+    spec:
+      affinity:
+        nodeAffinity:
+          requiredDuringSchedulingIgnoredDuringExecution:
+            nodeSelectorTerms:
+              - matchExpressions:
+                  - key: kubernetes.io/arch
+                    operator: NotIn
+                    values:
+                      - arm64
+      volumes:
+        - name: data
+          nfs:
+            path: /i-data/7a8af061/nfs/cart-actor
+            server: 10.10.1.10
+      imagePullSecrets:
+        - name: regcred
+      serviceAccountName: default
+      containers:
+        - image: registry.knatofs.se/go-cart-actor-amd64:latest
+          name: cart-actor-amd64
+          imagePullPolicy: Always
+          command: ["/go-cart-backoffice"]
+          lifecycle:
+            preStop:
+              exec:
+                command: ["sleep", "15"]
+          ports:
+            - containerPort: 8080
+              name: web
+          livenessProbe:
+            httpGet:
+              path: /livez
+              port: web
+            failureThreshold: 1
+            periodSeconds: 10
+          readinessProbe:
+            httpGet:
+              path: /readyz
+              port: web
+            failureThreshold: 2
+            initialDelaySeconds: 2
+            periodSeconds: 10
+          volumeMounts:
+            - mountPath: "/data"
+              name: data
+          resources:
+            limits:
+              memory: "768Mi"
+            requests:
+              memory: "70Mi"
+              cpu: "1200m"
+          env:
+            - name: TZ
+              value: "Europe/Stockholm"
+            - name: KLARNA_API_USERNAME
+              valueFrom:
+                secretKeyRef:
+                  name: klarna-api-credentials
+                  key: username
+            - name: KLARNA_API_PASSWORD
+              valueFrom:
+                secretKeyRef:
+                  name: klarna-api-credentials
+                  key: password
+            - name: AMQP_URL
+              value: "amqp://admin:12bananer@rabbitmq.dev:5672/"
+            # - name: BASE_URL
+            #   value: "https://s10n-no.tornberg.me"
+---
+apiVersion: apps/v1
+kind: Deployment
 metadata:
   labels:
     app: cart-actor
     arch: amd64
   name: cart-actor-x86
 spec:
-    replicas: 0
+  replicas: 3
   selector:
     matchLabels:
       app: cart-actor
@@ -55,6 +143,8 @@ spec:
           ports:
             - containerPort: 8080
               name: web
+            - containerPort: 8081
+              name: debug
             - containerPort: 1337
               name: rpc
           livenessProbe:
@@ -87,6 +177,10 @@ spec:
                 secretKeyRef:
                   name: klarna-api-credentials
                   key: username
+            - name: OTEL_RESOURCE_ATTRIBUTES
+              value: "service.name=cart,service.version=0.1.2"
+            - name: OTEL_EXPORTER_OTLP_ENDPOINT
+              value: "http://jaeger-collector.monitoring:4317"
             - name: KLARNA_API_PASSWORD
               valueFrom:
                 secretKeyRef:
@@ -113,7 +207,7 @@ metadata:
     arch: arm64
   name: cart-actor-arm64
 spec:
-    replicas: 3
+  replicas: 0
   selector:
     matchLabels:
       app: cart-actor
@@ -157,6 +251,8 @@ spec:
           ports:
             - containerPort: 8080
               name: web
+            - containerPort: 8081
+              name: debug
             - containerPort: 1337
               name: rpc
           livenessProbe:
@@ -184,6 +280,10 @@ spec:
           env:
             - name: TZ
               value: "Europe/Stockholm"
+            - name: OTEL_RESOURCE_ATTRIBUTES
+              value: "service.name=cart,service.version=0.1.2"
+            - name: OTEL_EXPORTER_OTLP_ENDPOINT
+              value: "http://jaeger-collector.monitoring:4317"
             - name: KLARNA_API_USERNAME
               valueFrom:
                 secretKeyRef:
@@ -212,7 +312,7 @@ apiVersion: v1
 metadata:
   name: cart-actor
   annotations:
-        prometheus.io/port: "8080"
+    prometheus.io/port: "8081"
     prometheus.io/scrape: "true"
     prometheus.io/path: "/metrics"
 spec:
@@ -222,16 +322,27 @@ spec:
     - name: web
       port: 8080
 ---
+kind: Service
+apiVersion: v1
+metadata:
+  name: cart-backoffice
+spec:
+  selector:
+    app: cart-backoffice
+  ports:
+    - name: web
+      port: 8080
+---
 apiVersion: networking.k8s.io/v1
 kind: Ingress
 metadata:
   name: cart-ingress
   annotations:
     cert-manager.io/cluster-issuer: letsencrypt-prod
-        # nginx.ingress.kubernetes.io/affinity: "cookie"
+    nginx.ingress.kubernetes.io/affinity: "cookie"
-        # nginx.ingress.kubernetes.io/session-cookie-name: "cart-affinity"
+    nginx.ingress.kubernetes.io/session-cookie-name: "cart-affinity"
-        # nginx.ingress.kubernetes.io/session-cookie-expires: "172800"
+    nginx.ingress.kubernetes.io/session-cookie-expires: "172800"
-        # nginx.ingress.kubernetes.io/session-cookie-max-age: "172800"
+    nginx.ingress.kubernetes.io/session-cookie-max-age: "172800"
     nginx.ingress.kubernetes.io/proxy-body-size: 4m
 spec:
   ingressClassName: nginx
@@ -250,3 +361,27 @@ spec:
                 name: cart-actor
                 port:
                   number: 8080
+---
+apiVersion: networking.k8s.io/v1
+kind: Ingress
+metadata:
+  name: cart-backend-ingress
+  annotations:
+    cert-manager.io/cluster-issuer: letsencrypt-prod
+spec:
+  ingressClassName: nginx
+  tls:
+    - hosts:
+        - slask-cart.tornberg.me
+      secretName: cart-backoffice-actor-tls-secret
+  rules:
+    - host: slask-cart.tornberg.me
+      http:
+        paths:
+          - path: /
+            pathType: Prefix
+            backend:
+              service:
+                name: cart-backoffice
+                port:
+                  number: 8080

discarded-host.go

@@ -1,84 +0,0 @@
-package main
-
-import (
-	"fmt"
-	"log"
-	"net"
-	"sync"
-	"time"
-)
-
-type DiscardedHost struct {
-	Host  string
-	Tries int
-}
-
-type DiscardedHostHandler struct {
-	mu           sync.RWMutex
-	port         int
-	hosts        []*DiscardedHost
-	onConnection *func(string)
-}
-
-func (d *DiscardedHostHandler) run() {
-	for range time.Tick(time.Second) {
-		d.mu.RLock()
-		lst := make([]*DiscardedHost, 0, len(d.hosts))
-		for _, host := range d.hosts {
-			if host.Tries >= 0 && host.Tries < 5 {
-				go d.testConnection(host)
-				lst = append(lst, host)
-			} else {
-				if host.Tries > 0 {
-					log.Printf("Host %s discarded after %d tries", host.Host, host.Tries)
-				}
-			}
-		}
-		d.mu.RUnlock()
-		d.mu.Lock()
-		d.hosts = lst
-		d.mu.Unlock()
-	}
-
-}
-
-func (d *DiscardedHostHandler) testConnection(host *DiscardedHost) {
-	addr := fmt.Sprintf("%s:%d", host.Host, d.port)
-	conn, err := net.Dial("tcp", addr)
-
-	if err != nil {
-		host.Tries++
-		if host.Tries >= 5 {
-			// Exceeded retry threshold; will be dropped by run loop.
-		}
-	} else {
-		conn.Close()
-		if d.onConnection != nil {
-			fn := *d.onConnection
-			fn(host.Host)
-		}
-	}
-}
-
-func NewDiscardedHostHandler(port int) *DiscardedHostHandler {
-	ret := &DiscardedHostHandler{
-		hosts: make([]*DiscardedHost, 0),
-		port:  port,
-	}
-	go ret.run()
-	return ret
-}
-
-func (d *DiscardedHostHandler) SetReconnectHandler(fn func(string)) {
-	d.onConnection = &fn
-}
-
-func (d *DiscardedHostHandler) AppendHost(host string) {
-	d.mu.Lock()
-	defer d.mu.Unlock()
-	log.Printf("Adding host %s to retry list", host)
-	d.hosts = append(d.hosts, &DiscardedHost{
-		Host:  host,
-		Tries: 0,
-	})
-}

disk-storage.go

@@ -1,70 +0,0 @@
-package main
-
-import (
-	"encoding/gob"
-	"fmt"
-	"os"
-	"time"
-)
-
-type DiskStorage struct {
-	stateFile string
-	lastSave  int64
-	LastSaves map[CartId]int64
-}
-
-func NewDiskStorage(stateFile string) (*DiskStorage, error) {
-	ret := &DiskStorage{
-		stateFile: stateFile,
-		LastSaves: make(map[CartId]int64),
-	}
-	err := ret.loadState()
-	return ret, err
-}
-
-func saveMessages(_ interface{}, _ CartId) error {
-	// No-op: legacy event log persistence removed in oneof refactor.
-	return nil
-}
-
-func getCartPath(id string) string {
-	return fmt.Sprintf("data/%s.prot", id)
-}
-
-func loadMessages(_ Grain, _ CartId) error {
-	// No-op: legacy replay removed in oneof refactor.
-	return nil
-}
-
-func (s *DiskStorage) saveState() error {
-	tmpFile := s.stateFile + "_tmp"
-	file, err := os.Create(tmpFile)
-	if err != nil {
-		return err
-	}
-	defer file.Close()
-	err = gob.NewEncoder(file).Encode(s.LastSaves)
-	if err != nil {
-		return err
-	}
-	os.Remove(s.stateFile + ".bak")
-	os.Rename(s.stateFile, s.stateFile+".bak")
-	return os.Rename(tmpFile, s.stateFile)
-}
-
-func (s *DiskStorage) loadState() error {
-	file, err := os.Open(s.stateFile)
-	if err != nil {
-		return err
-	}
-	defer file.Close()
-	return gob.NewDecoder(file).Decode(&s.LastSaves)
-}
-
-func (s *DiskStorage) Store(id CartId, _ *CartGrain) error {
-	// With the removal of the legacy message log, we only update the timestamp.
-	ts := time.Now().Unix()
-	s.LastSaves[id] = ts
-	s.lastSave = ts
-	return nil
-}

go.mod

@@ -1,12 +1,24 @@
 module git.tornberg.me/go-cart-actor
 
-go 1.25.1
+go 1.25.3
 
 require (
+	github.com/gogo/protobuf v1.3.2
 	github.com/google/uuid v1.6.0
-	github.com/matst80/slask-finder v0.0.0-20251009175145-ce05aff5a548
+	github.com/matst80/slask-finder v0.0.0-20251023104024-f788e5a51d68
 	github.com/prometheus/client_golang v1.23.2
 	github.com/rabbitmq/amqp091-go v1.10.0
+	github.com/redis/go-redis/v9 v9.16.0
+	go.opentelemetry.io/contrib/bridges/otelslog v0.13.0
+	go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp v0.63.0
+	go.opentelemetry.io/otel v1.38.0
+	go.opentelemetry.io/otel/exporters/otlp/otlplog/otlploggrpc v0.14.0
+	go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracegrpc v1.38.0
+	go.opentelemetry.io/otel/exporters/prometheus v0.60.0
+	go.opentelemetry.io/otel/log v0.14.0
+	go.opentelemetry.io/otel/sdk v1.38.0
+	go.opentelemetry.io/otel/sdk/log v0.14.0
+	go.opentelemetry.io/otel/sdk/metric v1.38.0
 	google.golang.org/grpc v1.76.0
 	google.golang.org/protobuf v1.36.10
 	k8s.io/api v0.34.1
@@ -15,14 +27,20 @@ require (
 )
 
 require (
-	github.com/RoaringBitmap/roaring/v2 v2.10.0 // indirect
+	github.com/RoaringBitmap/roaring/v2 v2.13.0 // indirect
 	github.com/beorn7/perks v1.0.1 // indirect
-	github.com/bits-and-blooms/bitset v1.24.0 // indirect
+	github.com/bits-and-blooms/bitset v1.24.1 // indirect
+	github.com/cenkalti/backoff/v5 v5.0.3 // indirect
 	github.com/cespare/xxhash/v2 v2.3.0 // indirect
 	github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc // indirect
+	github.com/dgryski/go-rendezvous v0.0.0-20200823014737-9f7001d12a5f // indirect
+	github.com/dprotaso/go-yit v0.0.0-20220510233725-9ba8df137936 // indirect
 	github.com/emicklei/go-restful/v3 v3.13.0 // indirect
+	github.com/felixge/httpsnoop v1.0.4 // indirect
 	github.com/fxamacker/cbor/v2 v2.9.0 // indirect
+	github.com/getkin/kin-openapi v0.132.0 // indirect
 	github.com/go-logr/logr v1.4.3 // indirect
+	github.com/go-logr/stdr v1.2.2 // indirect
 	github.com/go-openapi/jsonpointer v0.22.1 // indirect
 	github.com/go-openapi/jsonreference v0.21.2 // indirect
 	github.com/go-openapi/swag v0.25.1 // indirect
@@ -37,32 +55,55 @@ require (
 	github.com/go-openapi/swag/stringutils v0.25.1 // indirect
 	github.com/go-openapi/swag/typeutils v0.25.1 // indirect
 	github.com/go-openapi/swag/yamlutils v0.25.1 // indirect
-	github.com/gogo/protobuf v1.3.2 // indirect
 	github.com/google/gnostic-models v0.7.0 // indirect
 	github.com/google/go-cmp v0.7.0 // indirect
 	github.com/gorilla/schema v1.4.1 // indirect
+	github.com/grafana/regexp v0.0.0-20240518133315-a468a5bfb3bc // indirect
+	github.com/grpc-ecosystem/grpc-gateway/v2 v2.27.2 // indirect
+	github.com/josharian/intern v1.0.0 // indirect
 	github.com/json-iterator/go v1.1.12 // indirect
+	github.com/mailru/easyjson v0.7.7 // indirect
 	github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd // indirect
 	github.com/modern-go/reflect2 v1.0.3-0.20250322232337-35a7c28c31ee // indirect
+	github.com/mohae/deepcopy v0.0.0-20170929034955-c48cc78d4826 // indirect
 	github.com/mschoch/smat v0.2.0 // indirect
 	github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822 // indirect
-	github.com/pmezard/go-difflib v1.0.0 // indirect
+	github.com/oapi-codegen/oapi-codegen/v2 v2.5.0 // indirect
+	github.com/oasdiff/yaml v0.0.0-20250309154309-f31be36b4037 // indirect
+	github.com/oasdiff/yaml3 v0.0.0-20250309153720-d2182401db90 // indirect
+	github.com/perimeterx/marshmallow v1.1.5 // indirect
+	github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2 // indirect
 	github.com/prometheus/client_model v0.6.2 // indirect
 	github.com/prometheus/common v0.67.1 // indirect
-	github.com/prometheus/procfs v0.17.0 // indirect
+	github.com/prometheus/otlptranslator v0.0.2 // indirect
-	github.com/spf13/pflag v1.0.6 // indirect
+	github.com/prometheus/procfs v0.18.0 // indirect
+	github.com/speakeasy-api/jsonpath v0.6.0 // indirect
+	github.com/speakeasy-api/openapi-overlay v0.10.2 // indirect
+	github.com/spf13/pflag v1.0.10 // indirect
+	github.com/vmware-labs/yaml-jsonpath v0.3.2 // indirect
 	github.com/x448/float16 v0.8.4 // indirect
+	go.opentelemetry.io/auto/sdk v1.2.1 // indirect
+	go.opentelemetry.io/otel/exporters/otlp/otlptrace v1.38.0 // indirect
+	go.opentelemetry.io/otel/metric v1.38.0 // indirect
+	go.opentelemetry.io/otel/trace v1.38.0 // indirect
+	go.opentelemetry.io/proto/otlp v1.7.1 // indirect
 	go.yaml.in/yaml/v2 v2.4.3 // indirect
 	go.yaml.in/yaml/v3 v3.0.4 // indirect
+	golang.org/x/mod v0.29.0 // indirect
 	golang.org/x/net v0.46.0 // indirect
 	golang.org/x/oauth2 v0.32.0 // indirect
+	golang.org/x/sync v0.17.0 // indirect
 	golang.org/x/sys v0.37.0 // indirect
 	golang.org/x/term v0.36.0 // indirect
 	golang.org/x/text v0.30.0 // indirect
 	golang.org/x/time v0.14.0 // indirect
-	google.golang.org/genproto/googleapis/rpc v0.0.0-20251007200510-49b9836ed3ff // indirect
+	golang.org/x/tools v0.38.0 // indirect
+	google.golang.org/genproto/googleapis/api v0.0.0-20251022142026-3a174f9686a8 // indirect
+	google.golang.org/genproto/googleapis/rpc v0.0.0-20251022142026-3a174f9686a8 // indirect
 	gopkg.in/evanphx/json-patch.v4 v4.13.0 // indirect
 	gopkg.in/inf.v0 v0.9.1 // indirect
+	gopkg.in/yaml.v2 v2.4.0 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
 	k8s.io/klog/v2 v2.130.1 // indirect
 	k8s.io/kube-openapi v0.0.0-20250910181357-589584f1c912 // indirect
 	k8s.io/utils v0.0.0-20251002143259-bc988d571ff4 // indirect
@@ -71,3 +112,5 @@ require (
 	sigs.k8s.io/structured-merge-diff/v6 v6.3.0 // indirect
 	sigs.k8s.io/yaml v1.6.0 // indirect
 )
+
+tool github.com/oapi-codegen/oapi-codegen/v2/cmd/oapi-codegen

go.sum

@@ -1,20 +1,41 @@
-github.com/RoaringBitmap/roaring/v2 v2.10.0 h1:HbJ8Cs71lfCJyvmSptxeMX2PtvOC8yonlU0GQcy2Ak0=
+github.com/RoaringBitmap/roaring/v2 v2.13.0 h1:38BxJ6lGPcBLykIRCyYtViB/By3+a/iS9znKsiBbhNc=
-github.com/RoaringBitmap/roaring/v2 v2.10.0/go.mod h1:FiJcsfkGje/nZBZgCu0ZxCPOKD/hVXDS2dXi7/eUFE0=
+github.com/RoaringBitmap/roaring/v2 v2.13.0/go.mod h1:Mpi+oQ+3oCU7g1aF75Ib/XYCTqjTGpHI0f8djSZVY3I=
 github.com/beorn7/perks v1.0.1 h1:VlbKKnNfV8bJzeqoa4cOKqO6bYr3WgKZxO8Z16+hsOM=
 github.com/beorn7/perks v1.0.1/go.mod h1:G2ZrVWU2WbWT9wwq4/hrbKbnv/1ERSJQ0ibhJ6rlkpw=
-github.com/bits-and-blooms/bitset v1.12.0/go.mod h1:7hO7Gc7Pp1vODcmWvKMRA9BNmbv6a/7QIWpPxHddWR8=
+github.com/bits-and-blooms/bitset v1.24.1 h1:hqnfFbjjk3pxGa5E9Ho3hjoU7odtUuNmJ9Ao+Bo8s1c=
-github.com/bits-and-blooms/bitset v1.24.0 h1:H4x4TuulnokZKvHLfzVRTHJfFfnHEeSYJizujEZvmAM=
+github.com/bits-and-blooms/bitset v1.24.1/go.mod h1:7hO7Gc7Pp1vODcmWvKMRA9BNmbv6a/7QIWpPxHddWR8=
-github.com/bits-and-blooms/bitset v1.24.0/go.mod h1:7hO7Gc7Pp1vODcmWvKMRA9BNmbv6a/7QIWpPxHddWR8=
+github.com/bsm/ginkgo/v2 v2.12.0 h1:Ny8MWAHyOepLGlLKYmXG4IEkioBysk6GpaRTLC8zwWs=
+github.com/bsm/ginkgo/v2 v2.12.0/go.mod h1:SwYbGRRDovPVboqFv0tPTcG1sN61LM1Z4ARdbAV9g4c=
+github.com/bsm/gomega v1.27.10 h1:yeMWxP2pV2fG3FgAODIY8EiRE3dy0aeFYt4l7wh6yKA=
+github.com/bsm/gomega v1.27.10/go.mod h1:JyEr/xRbxbtgWNi8tIEVPUYZ5Dzef52k01W3YH0H+O0=
+github.com/cenkalti/backoff/v5 v5.0.3 h1:ZN+IMa753KfX5hd8vVaMixjnqRZ3y8CuJKRKj1xcsSM=
+github.com/cenkalti/backoff/v5 v5.0.3/go.mod h1:rkhZdG3JZukswDf7f0cwqPNk4K0sa+F97BxZthm/crw=
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+github.com/chzyer/logex v1.1.10/go.mod h1:+Ywpsq7O8HXn0nuIou7OrIPyXbp3wmkHB+jjWRnGsAI=
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 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
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 github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/dgryski/go-rendezvous v0.0.0-20200823014737-9f7001d12a5f h1:lO4WD4F/rVNCu3HqELle0jiPLLBs70cWOduZpkS1E78=
+github.com/dgryski/go-rendezvous v0.0.0-20200823014737-9f7001d12a5f/go.mod h1:cuUVRXasLTGF7a8hSLbxyZXjz+1KgoB3wDUb6vlszIc=
+github.com/dprotaso/go-yit v0.0.0-20191028211022-135eb7262960/go.mod h1:9HQzr9D/0PGwMEbC3d5AB7oi67+h4TsQqItC1GVYG58=
+github.com/dprotaso/go-yit v0.0.0-20220510233725-9ba8df137936 h1:PRxIJD8XjimM5aTknUK9w6DHLDox2r2M3DI4i2pnd3w=
+github.com/dprotaso/go-yit v0.0.0-20220510233725-9ba8df137936/go.mod h1:ttYvX5qlB+mlV1okblJqcSMtR4c52UKxDiX9GRBS8+Q=
 github.com/emicklei/go-restful/v3 v3.13.0 h1:C4Bl2xDndpU6nJ4bc1jXd+uTmYPVUwkD6bFY/oTyCes=
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+github.com/felixge/httpsnoop v1.0.4 h1:NFTV2Zj1bL4mc9sqWACXbQFVBBg2W3GPvqp8/ESS2Wg=
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+github.com/fsnotify/fsnotify v1.4.7/go.mod h1:jwhsz4b93w/PPRr/qN1Yymfu8t87LnFCMoQvtojpjFo=
+github.com/fsnotify/fsnotify v1.4.9 h1:hsms1Qyu0jgnwNXIxa+/V/PDsU6CfLf6CNO8H7IWoS4=
+github.com/fsnotify/fsnotify v1.4.9/go.mod h1:znqG4EE+3YCdAaPaxE2ZRY/06pZUdp0tY4IgpuI1SZQ=
 github.com/fxamacker/cbor/v2 v2.9.0 h1:NpKPmjDBgUfBms6tr6JZkTHtfFGcMKsw3eGcmD/sapM=
 github.com/fxamacker/cbor/v2 v2.9.0/go.mod h1:vM4b+DJCtHn+zz7h3FFp/hDAI9WNWCsZj23V5ytsSxQ=
+github.com/getkin/kin-openapi v0.132.0 h1:3ISeLMsQzcb5v26yeJrBcdTCEQTag36ZjaGk7MIRUwk=
+github.com/getkin/kin-openapi v0.132.0/go.mod h1:3OlG51PCYNsPByuiMB0t4fjnNlIDnaEDsjiKUV8nL58=
+github.com/go-logr/logr v1.2.2/go.mod h1:jdQByPbusPIv2/zmleS9BjJVeZ6kBagPoEUsqbVz/1A=
 github.com/go-logr/logr v1.4.3 h1:CjnDlHq8ikf6E492q6eKboGOC0T8CDaOvkHCIg8idEI=
 github.com/go-logr/logr v1.4.3/go.mod h1:9T104GzyrTigFIr8wt5mBrctHMim0Nb2HLGrmQ40KvY=
 github.com/go-logr/stdr v1.2.2 h1:hSWxHoqTgW2S2qGc0LTAI563KZ5YKYRhT3MFKZMbjag=
@@ -49,90 +70,181 @@ github.com/go-openapi/swag/typeutils v0.25.1 h1:rD/9HsEQieewNt6/k+JBwkxuAHktFtH3
 github.com/go-openapi/swag/typeutils v0.25.1/go.mod h1:9McMC/oCdS4BKwk2shEB7x17P6HmMmA6dQRtAkSnNb8=
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 github.com/go-openapi/swag/yamlutils v0.25.1/go.mod h1:cm9ywbzncy3y6uPm/97ysW8+wZ09qsks+9RS8fLWKqg=
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+github.com/go-task/slim-sprig v0.0.0-20210107165309-348f09dbbbc0/go.mod h1:fyg7847qk6SyHyPtNmDHnmrv/HOrqktSC+C9fM+CJOE=
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@@ -144,26 +256,50 @@ golang.org/x/crypto v0.0.0-20191011191535-87dc89f01550/go.mod h1:yigFU9vqHzYiE8U
 golang.org/x/crypto v0.0.0-20200622213623-75b288015ac9/go.mod h1:LzIPMQfyMNhhGPhUkYOs5KpL4U8rLKemX1yGLhDgUto=
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@@ -171,30 +307,51 @@ golang.org/x/time v0.14.0/go.mod h1:eL/Oa2bBBK0TkX57Fyni+NgnyQQN4LitPmob2Hjnqw4=
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grafana_dashboard_cart.json

@@ -0,0 +1,327 @@
+{
+  "uid": "cart-actors",
+  "title": "Cart Actor Cluster",
+  "timezone": "browser",
+  "refresh": "30s",
+  "schemaVersion": 38,
+  "version": 1,
+  "editable": true,
+  "graphTooltip": 0,
+  "panels": [
+    {
+      "type": "row",
+      "title": "Overview",
+      "gridPos": { "x": 0, "y": 0, "w": 24, "h": 1 },
+      "id": 1,
+      "collapsed": false
+    },
+    {
+      "type": "stat",
+      "title": "Active Grains",
+      "id": 2,
+      "gridPos": { "x": 0, "y": 1, "w": 6, "h": 4 },
+      "datasource": "${DS_PROMETHEUS}",
+      "targets": [
+        { "refId": "A", "expr": "cart_active_grains" }
+      ],
+      "options": {
+        "colorMode": "value",
+        "graphMode": "none",
+        "justifyMode": "center",
+        "reduceOptions": { "calcs": ["lastNotNull"], "fields": "", "values": false }
+      }
+    },
+    {
+      "type": "stat",
+      "title": "Grains In Pool",
+      "id": 3,
+      "gridPos": { "x": 6, "y": 1, "w": 6, "h": 4 },
+      "datasource": "${DS_PROMETHEUS}",
+      "targets": [
+        { "refId": "A", "expr": "cart_grains_in_pool" }
+      ],
+      "options": {
+        "colorMode": "value",
+        "graphMode": "none",
+        "justifyMode": "center",
+        "reduceOptions": { "calcs": ["lastNotNull"], "fields": "", "values": false }
+      }
+    },
+    {
+      "type": "stat",
+      "title": "Pool Usage %",
+      "id": 4,
+      "gridPos": { "x": 12, "y": 1, "w": 6, "h": 4 },
+      "datasource": "${DS_PROMETHEUS}",
+      "targets": [
+        { "refId": "A", "expr": "cart_grain_pool_usage * 100" }
+      ],
+      "units": "percent",
+      "options": {
+        "colorMode": "value",
+        "graphMode": "none",
+        "justifyMode": "center",
+        "reduceOptions": { "calcs": ["lastNotNull"] }
+      }
+    },
+    {
+      "type": "stat",
+      "title": "Connected Remotes",
+      "id": 5,
+      "gridPos": { "x": 18, "y": 1, "w": 6, "h": 4 },
+      "datasource": "${DS_PROMETHEUS}",
+      "targets": [
+        { "refId": "A", "expr": "connected_remotes" }
+      ],
+      "options": {
+        "colorMode": "value",
+        "graphMode": "none",
+        "justifyMode": "center",
+        "reduceOptions": { "calcs": ["lastNotNull"] }
+      }
+    },
+
+    {
+      "type": "row",
+      "title": "Mutations",
+      "gridPos": { "x": 0, "y": 5, "w": 24, "h": 1 },
+      "id": 6,
+      "collapsed": false
+    },
+    {
+      "type": "timeseries",
+      "title": "Mutation Rate (1m)",
+      "id": 7,
+      "gridPos": { "x": 0, "y": 6, "w": 12, "h": 8 },
+      "datasource": "${DS_PROMETHEUS}",
+      "targets": [
+        { "refId": "A", "expr": "rate(cart_mutations_total[1m])", "legendFormat": "mutations/s" },
+        { "refId": "B", "expr": "rate(cart_mutation_failures_total[1m])", "legendFormat": "failures/s" }
+      ],
+      "fieldConfig": { "defaults": { "unit": "ops" } }
+    },
+    {
+      "type": "stat",
+      "title": "Failure % (5m)",
+      "id": 8,
+      "gridPos": { "x": 12, "y": 6, "w": 6, "h": 4 },
+      "datasource": "${DS_PROMETHEUS}",
+      "targets": [
+        {
+          "refId": "A",
+          "expr": "100 * (increase(cart_mutation_failures_total[5m]) / clamp_max(increase(cart_mutations_total[5m]), 1))"
+        }
+      ],
+      "options": {
+        "colorMode": "value",
+        "graphMode": "none",
+        "justifyMode": "center",
+        "reduceOptions": { "calcs": ["lastNotNull"] }
+      }
+    },
+    {
+      "type": "timeseries",
+      "title": "Mutation Latency Quantiles",
+      "id": 9,
+      "gridPos": { "x": 18, "y": 6, "w": 6, "h": 8 },
+      "datasource": "${DS_PROMETHEUS}",
+      "targets": [
+        {
+          "refId": "A",
+          "expr": "histogram_quantile(0.50, sum(rate(cart_mutation_latency_seconds_bucket[5m])) by (le))",
+          "legendFormat": "p50"
+        },
+        {
+          "refId": "B",
+          "expr": "histogram_quantile(0.90, sum(rate(cart_mutation_latency_seconds_bucket[5m])) by (le))",
+          "legendFormat": "p90"
+        },
+        {
+          "refId": "C",
+          "expr": "histogram_quantile(0.99, sum(rate(cart_mutation_latency_seconds_bucket[5m])) by (le))",
+          "legendFormat": "p99"
+        }
+      ],
+      "fieldConfig": { "defaults": { "unit": "s" } }
+    },
+
+    {
+      "type": "row",
+      "title": "Event Log",
+      "gridPos": { "x": 0, "y": 14, "w": 24, "h": 1 },
+      "id": 10,
+      "collapsed": false
+    },
+    {
+      "type": "timeseries",
+      "title": "Event Append Rate (5m)",
+      "id": 11,
+      "gridPos": { "x": 0, "y": 15, "w": 8, "h": 6 },
+      "datasource": "${DS_PROMETHEUS}",
+      "targets": [
+        { "refId": "A", "expr": "rate(cart_event_log_appends_total[5m])", "legendFormat": "appends/s" }
+      ]
+    },
+    {
+      "type": "timeseries",
+      "title": "Event Bytes Written Rate (5m)",
+      "id": 12,
+      "gridPos": { "x": 8, "y": 15, "w": 8, "h": 6 },
+      "datasource": "${DS_PROMETHEUS}",
+      "targets": [
+        { "refId": "A", "expr": "rate(cart_event_log_bytes_written_total[5m])", "legendFormat": "bytes/s" }
+      ],
+      "fieldConfig": { "defaults": { "unit": "Bps" } }
+    },
+    {
+      "type": "stat",
+      "title": "Existing Log Files",
+      "id": 13,
+      "gridPos": { "x": 16, "y": 15, "w": 4, "h": 3 },
+      "datasource": "${DS_PROMETHEUS}",
+      "targets": [{ "refId": "A", "expr": "cart_event_log_files_existing" }],
+      "options": { "reduceOptions": { "calcs": ["lastNotNull"] } }
+    },
+    {
+      "type": "stat",
+      "title": "Last Append Age (s)",
+      "id": 14,
+      "gridPos": { "x": 20, "y": 15, "w": 4, "h": 3 },
+      "datasource": "${DS_PROMETHEUS}",
+      "targets": [
+        { "refId": "A", "expr": "(time() - cart_event_log_last_append_unix)" }
+      ],
+      "options": { "reduceOptions": { "calcs": ["lastNotNull"] } }
+    },
+    {
+      "type": "stat",
+      "title": "Replay Failures Total",
+      "id": 15,
+      "gridPos": { "x": 16, "y": 18, "w": 4, "h": 3 },
+      "datasource": "${DS_PROMETHEUS}",
+      "targets": [{ "refId": "A", "expr": "cart_event_log_replay_failures_total" }],
+      "options": { "reduceOptions": { "calcs": ["lastNotNull"] } }
+    },
+    {
+      "type": "stat",
+      "title": "Replay Duration p95 (5m)",
+      "id": 16,
+      "gridPos": { "x": 20, "y": 18, "w": 4, "h": 3 },
+      "datasource": "${DS_PROMETHEUS}",
+      "targets": [
+        {
+          "refId": "A",
+            "expr": "histogram_quantile(0.95, sum(rate(cart_event_log_replay_duration_seconds_bucket[5m])) by (le))"
+        }
+      ],
+      "options": { "reduceOptions": { "calcs": ["lastNotNull"] }, "fieldConfig": { "defaults": { "unit": "s" } } }
+    },
+
+    {
+      "type": "row",
+      "title": "Grain Lifecycle",
+      "gridPos": { "x": 0, "y": 21, "w": 24, "h": 1 },
+      "id": 17,
+      "collapsed": false
+    },
+    {
+      "type": "timeseries",
+      "title": "Spawn & Lookup Rates (1m)",
+      "id": 18,
+      "gridPos": { "x": 0, "y": 22, "w": 12, "h": 8 },
+      "datasource": "${DS_PROMETHEUS}",
+      "targets": [
+        { "refId": "A", "expr": "rate(cart_grain_spawned_total[1m])", "legendFormat": "spawns/s" },
+        { "refId": "B", "expr": "rate(cart_grain_lookups_total[1m])", "legendFormat": "lookups/s" }
+      ]
+    },
+    {
+      "type": "stat",
+      "title": "Negotiations Rate (5m)",
+      "id": 19,
+      "gridPos": { "x": 12, "y": 22, "w": 6, "h": 4 },
+      "datasource": "${DS_PROMETHEUS}",
+      "targets": [
+        { "refId": "A", "expr": "rate(cart_remote_negotiation_total[5m])" }
+      ],
+      "options": { "reduceOptions": { "calcs": ["lastNotNull"] }, "orientation": "horizontal" }
+    },
+    {
+      "type": "stat",
+      "title": "Mutations Total",
+      "id": 20,
+      "gridPos": { "x": 18, "y": 22, "w": 6, "h": 4 },
+      "datasource": "${DS_PROMETHEUS}",
+      "targets": [{ "refId": "A", "expr": "cart_mutations_total" }],
+      "options": { "reduceOptions": { "calcs": ["lastNotNull"] } }
+    },
+
+    {
+      "type": "row",
+      "title": "Event Log Errors",
+      "gridPos": { "x": 0, "y": 30, "w": 24, "h": 1 },
+      "id": 21,
+      "collapsed": false
+    },
+    {
+      "type": "stat",
+      "title": "Unknown Event Types",
+      "id": 22,
+      "gridPos": { "x": 0, "y": 31, "w": 6, "h": 4 },
+      "datasource": "${DS_PROMETHEUS}",
+      "targets": [{ "refId": "A", "expr": "cart_event_log_unknown_types_total" }],
+      "options": { "reduceOptions": { "calcs": ["lastNotNull"] } }
+    },
+    {
+      "type": "stat",
+      "title": "Event Mutation Errors",
+      "id": 23,
+      "gridPos": { "x": 6, "y": 31, "w": 6, "h": 4 },
+      "datasource": "${DS_PROMETHEUS}",
+      "targets": [{ "refId": "A", "expr": "cart_event_log_mutation_errors_total" }],
+      "options": { "reduceOptions": { "calcs": ["lastNotNull"] } }
+    },
+    {
+      "type": "stat",
+      "title": "Replay Success Total",
+      "id": 24,
+      "gridPos": { "x": 12, "y": 31, "w": 6, "h": 4 },
+      "datasource": "${DS_PROMETHEUS}",
+      "targets": [{ "refId": "A", "expr": "cart_event_log_replay_total" }],
+      "options": { "reduceOptions": { "calcs": ["lastNotNull"] } }
+    },
+    {
+      "type": "stat",
+      "title": "Replay Duration p50 (5m)",
+      "id": 25,
+      "gridPos": { "x": 18, "y": 31, "w": 6, "h": 4 },
+      "datasource": "${DS_PROMETHEUS}",
+      "targets": [
+        {
+          "refId": "A",
+          "expr": "histogram_quantile(0.50, sum(rate(cart_event_log_replay_duration_seconds_bucket[5m])) by (le))"
+        }
+      ],
+      "options": { "reduceOptions": { "calcs": ["lastNotNull"] }, "fieldConfig": { "defaults": { "unit": "s" } } }
+    }
+  ],
+  "templating": {
+    "list": [
+      {
+        "name": "DS_PROMETHEUS",
+        "label": "Prometheus",
+        "type": "datasource",
+        "query": "prometheus",
+        "current": { "text": "Prometheus", "value": "Prometheus" }
+      }
+    ]
+  },
+  "time": {
+    "from": "now-6h",
+    "to": "now"
+  },
+  "timepicker": {
+    "refresh_intervals": ["5s","10s","30s","1m","5m","15m","30m","1h"],
+    "time_options": ["5m","15m","30m","1h","6h","12h","24h","2d","7d"]
+  }
+}

grain-pool.go

@@ -1,244 +0,0 @@
-package main
-
-import (
-	"fmt"
-	"log"
-	"sync"
-	"time"
-
-	"github.com/prometheus/client_golang/prometheus"
-	"github.com/prometheus/client_golang/prometheus/promauto"
-)
-
-// grain-pool.go
-//
-// Migration Note:
-//   This file has been migrated to use uint64 cart keys internally (derived
-//   from the new CartID base62 representation). For backward compatibility,
-//   a deprecated legacy map keyed by CartId is maintained so existing code
-//   that directly indexes pool.grains with a CartId continues to compile
-//   until the full refactor across SyncedPool / remoteIndex is completed.
-//
-//   Authoritative storage: grains (map[uint64]*CartGrain)
-//   Legacy compatibility:  grainsLegacy (map[CartId]*CartGrain) - kept in sync.
-//
-//   Once all external usages are updated to rely on helper accessors,
-//   grainsLegacy can be removed.
-//
-// ---------------------------------------------------------------------------
-
-var (
-	poolGrains = promauto.NewGauge(prometheus.GaugeOpts{
-		Name: "cart_grains_in_pool",
-		Help: "The total number of grains in the pool",
-	})
-	poolSize = promauto.NewGauge(prometheus.GaugeOpts{
-		Name: "cart_pool_size",
-		Help: "The total number of mutations",
-	})
-	poolUsage = promauto.NewGauge(prometheus.GaugeOpts{
-		Name: "cart_grain_pool_usage",
-		Help: "The current usage of the grain pool",
-	})
-)
-
-// GrainPool interface remains legacy-compatible.
-type GrainPool interface {
-	Apply(id CartId, mutation interface{}) (*CartGrain, error)
-	Get(id CartId) (*CartGrain, error)
-}
-
-// Ttl keeps expiry info
-type Ttl struct {
-	Expires time.Time
-	Grain   *CartGrain
-}
-
-// GrainLocalPool now stores grains keyed by uint64 (CartKey).
-type GrainLocalPool struct {
-	mu       sync.RWMutex
-	grains   map[uint64]*CartGrain // authoritative only
-	expiry   []Ttl
-	spawn    func(id CartId) (*CartGrain, error)
-	Ttl      time.Duration
-	PoolSize int
-}
-
-// NewGrainLocalPool constructs a new pool.
-func NewGrainLocalPool(size int, ttl time.Duration, spawn func(id CartId) (*CartGrain, error)) *GrainLocalPool {
-	ret := &GrainLocalPool{
-		spawn:    spawn,
-		grains:   make(map[uint64]*CartGrain),
-		expiry:   make([]Ttl, 0),
-		Ttl:      ttl,
-		PoolSize: size,
-	}
-	cartPurge := time.NewTicker(time.Minute)
-	go func() {
-		for range cartPurge.C {
-			ret.Purge()
-		}
-	}()
-	return ret
-}
-
-// keyFromCartId derives the uint64 key from a legacy CartId deterministically.
-func keyFromCartId(id CartId) uint64 {
-	return LegacyToCartKey(id)
-}
-
-// storeGrain indexes a grain in both maps.
-func (p *GrainLocalPool) storeGrain(id CartId, g *CartGrain) {
-	k := keyFromCartId(id)
-	p.grains[k] = g
-}
-
-// deleteGrain removes a grain from both maps.
-func (p *GrainLocalPool) deleteGrain(id CartId) {
-	k := keyFromCartId(id)
-	delete(p.grains, k)
-}
-
-// SetAvailable pre-populates placeholder entries (legacy signature).
-func (p *GrainLocalPool) SetAvailable(availableWithLastChangeUnix map[CartId]int64) {
-	p.mu.Lock()
-	defer p.mu.Unlock()
-	for id := range availableWithLastChangeUnix {
-		k := keyFromCartId(id)
-		if _, ok := p.grains[k]; !ok {
-			p.grains[k] = nil
-			p.expiry = append(p.expiry, Ttl{
-				Expires: time.Now().Add(p.Ttl),
-				Grain:   nil,
-			})
-		}
-	}
-}
-
-// Purge removes expired grains.
-func (p *GrainLocalPool) Purge() {
-	lastChangeTime := time.Now().Add(-p.Ttl)
-	keepChanged := lastChangeTime.Unix()
-
-	p.mu.Lock()
-	defer p.mu.Unlock()
-
-	for i := 0; i < len(p.expiry); i++ {
-		item := p.expiry[i]
-		if item.Grain == nil {
-			continue
-		}
-		if item.Expires.Before(time.Now()) {
-			if item.Grain.GetLastChange() > keepChanged {
-				log.Printf("Expired item %s changed, keeping", item.Grain.GetId())
-				if i < len(p.expiry)-1 {
-					p.expiry = append(p.expiry[:i], p.expiry[i+1:]...)
-					p.expiry = append(p.expiry, item)
-				} else {
-					// move last to end (noop)
-					p.expiry = append(p.expiry[:i], item)
-				}
-			} else {
-				log.Printf("Item %s expired", item.Grain.GetId())
-				p.deleteGrain(item.Grain.GetId())
-				if i < len(p.expiry)-1 {
-					p.expiry = append(p.expiry[:i], p.expiry[i+1:]...)
-				} else {
-					p.expiry = p.expiry[:i]
-				}
-			}
-		} else {
-			break
-		}
-	}
-}
-
-// GetGrains returns a legacy view of grains (copy) for compatibility.
-func (p *GrainLocalPool) GetGrains() map[CartId]*CartGrain {
-	p.mu.RLock()
-	defer p.mu.RUnlock()
-	out := make(map[CartId]*CartGrain, len(p.grains))
-	for _, g := range p.grains {
-		if g != nil {
-			out[g.GetId()] = g
-		}
-	}
-	return out
-}
-
-// statsUpdate updates Prometheus gauges asynchronously.
-func (p *GrainLocalPool) statsUpdate() {
-	go func(size int) {
-		l := float64(size)
-		ps := float64(p.PoolSize)
-		poolUsage.Set(l / ps)
-		poolGrains.Set(l)
-		poolSize.Set(ps)
-	}(len(p.grains))
-}
-
-// GetGrain retrieves or spawns a grain (legacy id signature).
-func (p *GrainLocalPool) GetGrain(id CartId) (*CartGrain, error) {
-	grainLookups.Inc()
-	k := keyFromCartId(id)
-
-	p.mu.RLock()
-	grain, ok := p.grains[k]
-	p.mu.RUnlock()
-
-	var err error
-	if grain == nil || !ok {
-		p.mu.Lock()
-		// Re-check under write lock
-		grain, ok = p.grains[k]
-		if grain == nil || !ok {
-			// Capacity check
-			if len(p.grains) >= p.PoolSize && len(p.expiry) > 0 {
-				if p.expiry[0].Expires.Before(time.Now()) && p.expiry[0].Grain != nil {
-					oldId := p.expiry[0].Grain.GetId()
-					p.deleteGrain(oldId)
-					p.expiry = p.expiry[1:]
-				} else {
-					p.mu.Unlock()
-					return nil, fmt.Errorf("pool is full")
-				}
-			}
-			grain, err = p.spawn(id)
-			if err == nil {
-				p.storeGrain(id, grain)
-			}
-		}
-		p.mu.Unlock()
-		p.statsUpdate()
-	}
-
-	return grain, err
-}
-
-// Apply applies a mutation (legacy compatibility).
-func (p *GrainLocalPool) Apply(id CartId, mutation interface{}) (*CartGrain, error) {
-	grain, err := p.GetGrain(id)
-	if err != nil || grain == nil {
-		return nil, err
-	}
-	return grain.Apply(mutation, false)
-}
-
-// Get returns current state (legacy wrapper).
-func (p *GrainLocalPool) Get(id CartId) (*CartGrain, error) {
-	return p.GetGrain(id)
-}
-
-// DebugGrainCount returns counts for debugging.
-func (p *GrainLocalPool) DebugGrainCount() (authoritative int) {
-	p.mu.RLock()
-	defer p.mu.RUnlock()
-	return len(p.grains)
-}
-
-// UnsafePointerToLegacyMap exposes the legacy map pointer (for transitional
-// tests that still poke the field directly). DO NOT rely on this long-term.
-func (p *GrainLocalPool) UnsafePointerToLegacyMap() uintptr {
-	// Legacy map removed; retained only to satisfy any transitional callers.
-	return 0
-}

grpc_integration_test.go

@@ -1,115 +0,0 @@
-package main
-
-import (
-	"context"
-	"fmt"
-	"testing"
-	"time"
-
-	messages "git.tornberg.me/go-cart-actor/proto"
-	"google.golang.org/grpc"
-)
-
-// TestCartActorMutationAndState validates end-to-end gRPC mutation + state retrieval
-// against a locally started gRPC server (single-node scenario).
-// This test uses the new per-mutation AddItem RPC (breaking v2 API) to avoid external product fetch logic
-// fetching logic (FetchItem) which would require network I/O.
-func TestCartActorMutationAndState(t *testing.T) {
-	// Setup local grain pool + synced pool (no discovery, single host)
-	pool := NewGrainLocalPool(1024, time.Minute, spawn)
-	synced, err := NewSyncedPool(pool, "127.0.0.1", nil)
-	if err != nil {
-		t.Fatalf("NewSyncedPool error: %v", err)
-	}
-
-	// Start gRPC server (CartActor + ControlPlane) on :1337
-	grpcSrv, err := StartGRPCServer(":1337", pool, synced)
-	if err != nil {
-		t.Fatalf("StartGRPCServer error: %v", err)
-	}
-	defer grpcSrv.GracefulStop()
-
-	// Dial the local server
-	ctx, cancel := context.WithTimeout(context.Background(), 3*time.Second)
-	defer cancel()
-	conn, err := grpc.DialContext(ctx, "127.0.0.1:1337",
-		grpc.WithInsecure(),
-		grpc.WithBlock(),
-	)
-	if err != nil {
-		t.Fatalf("grpc.Dial error: %v", err)
-	}
-	defer conn.Close()
-
-	cartClient := messages.NewCartActorClient(conn)
-
-	// Create a short cart id (<=16 chars so it fits into the fixed CartId 16-byte array cleanly)
-	cartID := fmt.Sprintf("cart-%d", time.Now().UnixNano())
-
-	// Build an AddItem payload (bypasses FetchItem to keep test deterministic)
-	addItem := &messages.AddItem{
-		ItemId:   1,
-		Quantity: 1,
-		Price:    1000,
-		OrgPrice: 1000,
-		Sku:      "test-sku",
-		Name:     "Test SKU",
-		Image:    "/img.png",
-		Stock:    2, // InStock
-		Tax:      2500,
-		Country:  "se",
-	}
-
-	// Issue AddItem RPC directly (breaking v2 API)
-	addResp, err := cartClient.AddItem(context.Background(), &messages.AddItemRequest{
-		CartId:          cartID,
-		ClientTimestamp: time.Now().Unix(),
-		Payload:         addItem,
-	})
-	if err != nil {
-		t.Fatalf("AddItem RPC error: %v", err)
-	}
-	if addResp.StatusCode != 200 {
-		t.Fatalf("AddItem returned non-200 status: %d, error: %s", addResp.StatusCode, addResp.GetError())
-	}
-
-	// Validate the response state (from AddItem)
-	state := addResp.GetState()
-	if state == nil {
-		t.Fatalf("AddItem response state is nil")
-	}
-
-	// (Removed obsolete Mutate response handling)
-
-	if len(state.Items) != 1 {
-		t.Fatalf("Expected 1 item after AddItem, got %d", len(state.Items))
-	}
-	if state.Items[0].Sku != "test-sku" {
-		t.Fatalf("Unexpected item SKU: %s", state.Items[0].Sku)
-	}
-
-	// Issue GetState RPC
-	getResp, err := cartClient.GetState(context.Background(), &messages.StateRequest{
-		CartId: cartID,
-	})
-	if err != nil {
-		t.Fatalf("GetState RPC error: %v", err)
-	}
-	if getResp.StatusCode != 200 {
-		t.Fatalf("GetState returned non-200 status: %d, error: %s", getResp.StatusCode, getResp.GetError())
-	}
-
-	state2 := getResp.GetState()
-	if state2 == nil {
-		t.Fatalf("GetState response state is nil")
-	}
-
-	if len(state2.Items) != 1 {
-		t.Fatalf("Expected 1 item in GetState, got %d", len(state2.Items))
-	}
-	if state2.Items[0].Sku != "test-sku" {
-		t.Fatalf("Unexpected SKU in GetState: %s", state2.Items[0].Sku)
-	}
-}
-
-// Legacy serialization helper removed (oneof envelope used directly)

grpc_server.go

@@ -1,280 +0,0 @@
-package main
-
-import (
-	"context"
-	"fmt"
-	"log"
-	"net"
-	"time"
-
-	messages "git.tornberg.me/go-cart-actor/proto"
-	"google.golang.org/grpc"
-	"google.golang.org/grpc/reflection"
-)
-
-// cartActorGRPCServer implements the CartActor and ControlPlane gRPC services.
-// It delegates cart operations to a grain pool and cluster operations to a synced pool.
-type cartActorGRPCServer struct {
-	messages.UnimplementedCartActorServer
-	messages.UnimplementedControlPlaneServer
-
-	pool       GrainPool   // For cart state mutations and queries
-	syncedPool *SyncedPool // For cluster membership and control
-}
-
-// NewCartActorGRPCServer creates and initializes the server.
-func NewCartActorGRPCServer(pool GrainPool, syncedPool *SyncedPool) *cartActorGRPCServer {
-	return &cartActorGRPCServer{
-		pool:       pool,
-		syncedPool: syncedPool,
-	}
-}
-
-// applyMutation routes a single cart mutation to the target grain (used by per-mutation RPC handlers).
-func (s *cartActorGRPCServer) applyMutation(cartID string, mutation interface{}) *messages.CartMutationReply {
-	// Canonicalize or preserve legacy id (do NOT hash-rewrite legacy textual ids)
-	cid, _, wasBase62, cerr := CanonicalizeOrLegacy(cartID)
-	if cerr != nil {
-		return &messages.CartMutationReply{
-			StatusCode:      500,
-			Result:          &messages.CartMutationReply_Error{Error: fmt.Sprintf("cart_id canonicalization failed: %v", cerr)},
-			ServerTimestamp: time.Now().Unix(),
-		}
-	}
-	_ = wasBase62 // placeholder; future: propagate canonical id in reply metadata
-	legacy := CartIDToLegacy(cid)
-	grain, err := s.pool.Apply(legacy, mutation)
-	if err != nil {
-		return &messages.CartMutationReply{
-			StatusCode:      500,
-			Result:          &messages.CartMutationReply_Error{Error: err.Error()},
-			ServerTimestamp: time.Now().Unix(),
-		}
-	}
-	cartState := ToCartState(grain)
-	return &messages.CartMutationReply{
-		StatusCode:      200,
-		Result:          &messages.CartMutationReply_State{State: cartState},
-		ServerTimestamp: time.Now().Unix(),
-	}
-}
-
-func (s *cartActorGRPCServer) AddRequest(ctx context.Context, req *messages.AddRequestRequest) (*messages.CartMutationReply, error) {
-	if req.GetCartId() == "" {
-		return &messages.CartMutationReply{
-			StatusCode:      400,
-			Result:          &messages.CartMutationReply_Error{Error: "cart_id is required"},
-			ServerTimestamp: time.Now().Unix(),
-		}, nil
-	}
-	return s.applyMutation(req.GetCartId(), req.GetPayload()), nil
-}
-
-func (s *cartActorGRPCServer) AddItem(ctx context.Context, req *messages.AddItemRequest) (*messages.CartMutationReply, error) {
-	if req.GetCartId() == "" {
-		return &messages.CartMutationReply{
-			StatusCode:      400,
-			Result:          &messages.CartMutationReply_Error{Error: "cart_id is required"},
-			ServerTimestamp: time.Now().Unix(),
-		}, nil
-	}
-	return s.applyMutation(req.GetCartId(), req.GetPayload()), nil
-}
-
-func (s *cartActorGRPCServer) RemoveItem(ctx context.Context, req *messages.RemoveItemRequest) (*messages.CartMutationReply, error) {
-	if req.GetCartId() == "" {
-		return &messages.CartMutationReply{
-			StatusCode:      400,
-			Result:          &messages.CartMutationReply_Error{Error: "cart_id is required"},
-			ServerTimestamp: time.Now().Unix(),
-		}, nil
-	}
-	return s.applyMutation(req.GetCartId(), req.GetPayload()), nil
-}
-
-func (s *cartActorGRPCServer) RemoveDelivery(ctx context.Context, req *messages.RemoveDeliveryRequest) (*messages.CartMutationReply, error) {
-	if req.GetCartId() == "" {
-		return &messages.CartMutationReply{
-			StatusCode:      400,
-			Result:          &messages.CartMutationReply_Error{Error: "cart_id is required"},
-			ServerTimestamp: time.Now().Unix(),
-		}, nil
-	}
-	return s.applyMutation(req.GetCartId(), req.GetPayload()), nil
-}
-
-func (s *cartActorGRPCServer) ChangeQuantity(ctx context.Context, req *messages.ChangeQuantityRequest) (*messages.CartMutationReply, error) {
-	if req.GetCartId() == "" {
-		return &messages.CartMutationReply{
-			StatusCode:      400,
-			Result:          &messages.CartMutationReply_Error{Error: "cart_id is required"},
-			ServerTimestamp: time.Now().Unix(),
-		}, nil
-	}
-	return s.applyMutation(req.GetCartId(), req.GetPayload()), nil
-}
-
-func (s *cartActorGRPCServer) SetDelivery(ctx context.Context, req *messages.SetDeliveryRequest) (*messages.CartMutationReply, error) {
-	if req.GetCartId() == "" {
-		return &messages.CartMutationReply{
-			StatusCode:      400,
-			Result:          &messages.CartMutationReply_Error{Error: "cart_id is required"},
-			ServerTimestamp: time.Now().Unix(),
-		}, nil
-	}
-	return s.applyMutation(req.GetCartId(), req.GetPayload()), nil
-}
-
-func (s *cartActorGRPCServer) SetPickupPoint(ctx context.Context, req *messages.SetPickupPointRequest) (*messages.CartMutationReply, error) {
-	if req.GetCartId() == "" {
-		return &messages.CartMutationReply{
-			StatusCode:      400,
-			Result:          &messages.CartMutationReply_Error{Error: "cart_id is required"},
-			ServerTimestamp: time.Now().Unix(),
-		}, nil
-	}
-	return s.applyMutation(req.GetCartId(), req.GetPayload()), nil
-}
-
-/*
-Checkout RPC removed. Checkout is handled at the HTTP layer (PoolServer.HandleCheckout).
-*/
-
-func (s *cartActorGRPCServer) SetCartItems(ctx context.Context, req *messages.SetCartItemsRequest) (*messages.CartMutationReply, error) {
-	if req.GetCartId() == "" {
-		return &messages.CartMutationReply{
-			StatusCode:      400,
-			Result:          &messages.CartMutationReply_Error{Error: "cart_id is required"},
-			ServerTimestamp: time.Now().Unix(),
-		}, nil
-	}
-	return s.applyMutation(req.GetCartId(), req.GetPayload()), nil
-}
-
-func (s *cartActorGRPCServer) OrderCompleted(ctx context.Context, req *messages.OrderCompletedRequest) (*messages.CartMutationReply, error) {
-	if req.GetCartId() == "" {
-		return &messages.CartMutationReply{
-			StatusCode:      400,
-			Result:          &messages.CartMutationReply_Error{Error: "cart_id is required"},
-			ServerTimestamp: time.Now().Unix(),
-		}, nil
-	}
-	return s.applyMutation(req.GetCartId(), req.GetPayload()), nil
-}
-
-// GetState retrieves the current state of a cart grain.
-func (s *cartActorGRPCServer) GetState(ctx context.Context, req *messages.StateRequest) (*messages.StateReply, error) {
-	if req.GetCartId() == "" {
-		return &messages.StateReply{
-			StatusCode: 400,
-			Result:     &messages.StateReply_Error{Error: "cart_id is required"},
-		}, nil
-	}
-	// Canonicalize / upgrade incoming cart id (preserve legacy strings)
-	cid, _, _, cerr := CanonicalizeOrLegacy(req.GetCartId())
-	if cerr != nil {
-		return &messages.StateReply{
-			StatusCode: 500,
-			Result:     &messages.StateReply_Error{Error: fmt.Sprintf("cart_id canonicalization failed: %v", cerr)},
-		}, nil
-	}
-	legacy := CartIDToLegacy(cid)
-
-	grain, err := s.pool.Get(legacy)
-	if err != nil {
-		return &messages.StateReply{
-			StatusCode: 500,
-			Result:     &messages.StateReply_Error{Error: err.Error()},
-		}, nil
-	}
-
-	cartState := ToCartState(grain)
-
-	return &messages.StateReply{
-		StatusCode: 200,
-		Result:     &messages.StateReply_State{State: cartState},
-	}, nil
-}
-
-// ControlPlane: Ping
-func (s *cartActorGRPCServer) Ping(ctx context.Context, _ *messages.Empty) (*messages.PingReply, error) {
-	return &messages.PingReply{
-		Host:     s.syncedPool.Hostname,
-		UnixTime: time.Now().Unix(),
-	}, nil
-}
-
-// ControlPlane: Negotiate (merge host views)
-func (s *cartActorGRPCServer) Negotiate(ctx context.Context, req *messages.NegotiateRequest) (*messages.NegotiateReply, error) {
-	hostSet := make(map[string]struct{})
-	// Caller view
-	for _, h := range req.GetKnownHosts() {
-		if h != "" {
-			hostSet[h] = struct{}{}
-		}
-	}
-	// This host
-	hostSet[s.syncedPool.Hostname] = struct{}{}
-	// Known remotes
-	s.syncedPool.mu.RLock()
-	for h := range s.syncedPool.remoteHosts {
-		hostSet[h] = struct{}{}
-	}
-	s.syncedPool.mu.RUnlock()
-
-	out := make([]string, 0, len(hostSet))
-	for h := range hostSet {
-		out = append(out, h)
-	}
-	return &messages.NegotiateReply{Hosts: out}, nil
-}
-
-// ControlPlane: GetCartIds (locally owned carts only)
-func (s *cartActorGRPCServer) GetCartIds(ctx context.Context, _ *messages.Empty) (*messages.CartIdsReply, error) {
-	s.syncedPool.local.mu.RLock()
-	ids := make([]string, 0, len(s.syncedPool.local.grains))
-	for _, g := range s.syncedPool.local.grains {
-		if g == nil {
-			continue
-		}
-		ids = append(ids, g.GetId().String())
-	}
-	s.syncedPool.local.mu.RUnlock()
-	return &messages.CartIdsReply{CartIds: ids}, nil
-}
-
-// ControlPlane: Closing (peer shutdown notification)
-func (s *cartActorGRPCServer) Closing(ctx context.Context, req *messages.ClosingNotice) (*messages.OwnerChangeAck, error) {
-	if req.GetHost() != "" {
-		s.syncedPool.RemoveHost(req.GetHost())
-	}
-	return &messages.OwnerChangeAck{
-		Accepted: true,
-		Message:  "removed host",
-	}, nil
-}
-
-// StartGRPCServer configures and starts the unified gRPC server on the given address.
-// It registers both the CartActor and ControlPlane services.
-func StartGRPCServer(addr string, pool GrainPool, syncedPool *SyncedPool) (*grpc.Server, error) {
-	lis, err := net.Listen("tcp", addr)
-	if err != nil {
-		return nil, fmt.Errorf("failed to listen: %w", err)
-	}
-
-	grpcServer := grpc.NewServer()
-	server := NewCartActorGRPCServer(pool, syncedPool)
-
-	messages.RegisterCartActorServer(grpcServer, server)
-	messages.RegisterControlPlaneServer(grpcServer, server)
-	reflection.Register(grpcServer)
-
-	log.Printf("gRPC server listening on %s", addr)
-	go func() {
-		if err := grpcServer.Serve(lis); err != nil {
-			log.Fatalf("failed to serve gRPC: %v", err)
-		}
-	}()
-
-	return grpcServer, nil
-}

k6/README.md

@@ -0,0 +1,174 @@
+# k6 Load Tests for Cart API
+
+This directory contains a k6 script (`cart_load_test.js`) to stress and observe the cart actor HTTP API.
+
+## Contents
+
+- `cart_load_test.js` – primary k6 scenario script
+- `README.md` – this file
+
+## Prerequisites
+
+- Node not required (k6 runs standalone)
+- k6 installed (>= v0.43 recommended)
+- Prometheus + Grafana (optional) if you want to correlate with the dashboard you generated
+- A running cart service exposing HTTP endpoints at (default) `http://localhost:8080/cart`
+
+## Endpoints Exercised
+
+The script exercises (per iteration):
+
+1. `GET /cart/` – ensure / fetch cart state (creates cart if missing; sets `cartid` & `cartowner` cookies)
+2. `POST /cart/` – add item mutation (random SKU & quantity)
+3. `GET /cart/` – fetch after mutations
+4. `GET /cart/checkout` – occasionally (~2% of iterations) to simulate checkout start
+
+You can extend it easily to hit deliveries, quantity changes, or removal endpoints.
+
+## Environment Variables
+
+| Variable        | Purpose                                      | Default                 |
+|-----------------|----------------------------------------------|-------------------------|
+| `BASE_URL`      | Base URL root (either host or host/cart)     | `http://localhost:8080/cart` |
+| `VUS`           | VUs for steady_mutations scenario            | `20`                    |
+| `DURATION`      | Duration for steady_mutations scenario       | `5m`                    |
+| `RAMP_TARGET`   | Peak VUs for ramp_up scenario                 | `50`                    |
+
+You can also disable one scenario by editing `options.scenarios` inside the script.
+
+Example run:
+
+```bash
+k6 run \
+  -e BASE_URL=https://cart.prod.example.com/cart \
+  -e VUS=40 \
+  -e DURATION=10m \
+  -e RAMP_TARGET=120 \
+  k6/cart_load_test.js
+```
+
+## Metrics (Custom)
+
+The script defines additional k6 metrics:
+
+- `cart_add_item_duration` (Trend) – latency of POST add item
+- `cart_fetch_duration` (Trend) – latency of GET cart state
+- `cart_checkout_duration` (Trend) – latency of checkout
+- `cart_items_added` (Counter) – successful add item operations
+- `cart_checkout_calls` (Counter) – successful checkout calls
+
+Thresholds (in `options.thresholds`) enforce basic SLO:
+- Mutation failure rate < 2%
+- p90 mutation latency < 800 ms
+- p99 overall HTTP latency < 1500 ms
+
+Adjust thresholds to your environment if they trigger prematurely.
+
+## Cookies & Stickiness
+
+The script preserves:
+- `cartid` – cart identity (server sets expiry separately)
+- `cartowner` – owning host for sticky routing
+
+If your load balancer or ingress enforces affinity based on these cookies, traffic will naturally concentrate on the originally claimed host for each cart under test.
+
+## SKU Set
+
+SKUs used (randomly selected each mutation):
+
+```
+778290 778345 778317 778277 778267 778376 778244 778384
+778365 778377 778255 778286 778246 778270 778266 778285
+778329 778425 778407 778418 778430 778469 778358 778351
+778319 778307 778278 778251 778253 778261 778263 778273
+778281 778294 778297 778302
+```
+
+To add/remove SKUs, edit the `SKUS` array. Keeping it non-empty and moderately sized helps randomization.
+
+## Extending the Script
+
+### Add Quantity Change
+
+```js
+function changeQuantity(itemId, newQty) {
+  const payload = JSON.stringify({ Id: itemId, Qty: newQty });
+  http.put(baseUrl() + '/', payload, { headers: headers() });
+}
+```
+
+### Remove Item
+
+```js
+function removeItem(itemId) {
+  http.del(baseUrl() + '/' + itemId, null, { headers: headers() });
+}
+```
+
+### Add Delivery
+
+```js
+function addDelivery(itemIds) {
+  const payload = JSON.stringify({ provider: "POSTNORD", items: itemIds });
+  http.post(baseUrl() + '/delivery', payload, { headers: headers() });
+}
+```
+
+You can integrate these into the iteration loop with probabilities.
+
+## Output Summary
+
+`handleSummary` outputs a JSON summary to stdout:
+- Average & p95 mutation latencies (if present)
+- Fetch p95
+- Checkout count
+- Check statuses
+
+Redirect or parse that output for CI pipelines.
+
+## Running in CI
+
+Use shorter durations (e.g. `DURATION=2m VUS=10`) to keep builds fast. Fail build on threshold breaches:
+
+```bash
+k6 run -e BASE_URL=$TARGET -e VUS=10 -e DURATION=2m k6/cart_load_test.js || exit 1
+```
+
+## Correlating with Prometheus / Grafana
+
+During load, observe:
+- `cart_mutations_total` growth and latency histograms
+- Event log write rate (`cart_event_log_appends_total`)
+- Pool usage (`cart_grain_pool_usage`) and spawn rate (`cart_grain_spawned_total`)
+- Failure counters (`cart_mutation_failures_total`) ensure they remain low
+
+If mutation latency spikes without high error rate, inspect external dependencies (e.g., product fetcher or Klarna endpoints).
+
+## Common Tuning Tips
+
+| Symptom                             | Potential Adjustment                              |
+|------------------------------------|---------------------------------------------------|
+| High latency p99                   | Increase CPU/memory, optimize mutation handlers   |
+| Pool at capacity                   | Raise pool size argument or TTL                   |
+| Frequent cart eviction mid-test    | Confirm TTL is sliding (now 2h on mutation)       |
+| High replay duration               | Consider snapshot + truncate event logs           |
+| Uneven host load                   | Verify `cartowner` cookie is respected upstream   |
+
+## Safety / Load Guardrails
+
+- Start with low VUs (5–10) and short duration.
+- Scale incrementally to find saturation points.
+- If using production endpoints, coordinate off-peak runs.
+
+## License / Attribution
+
+This test script is tailored for your internal cart actor system; adapt freely. k6 is open-source (AGPL v3). Ensure compliance if redistributing.
+
+---
+
+Feel free to request:
+- A variant script for spike tests
+- WebSocket / long poll integration (if added later)
+- Synthetic error injection harness
+
+Happy load testing!

k6/cart_load_test.js

@@ -0,0 +1,248 @@
+import http from "k6/http";
+import { check, sleep, group } from "k6";
+import { Counter, Trend } from "k6/metrics";
+
+// ---------------- Configuration ----------------
+export const options = {
+    // Adjust vus/duration for your environment
+    scenarios: {
+        steady_mutations: {
+            executor: "constant-vus",
+            vus: __ENV.VUS ? parseInt(__ENV.VUS, 10) : 20,
+            duration: __ENV.DURATION || "5m",
+            gracefulStop: "30s",
+        },
+        ramp_up: {
+            executor: "ramping-vus",
+            startVUs: 0,
+            stages: [
+                {
+                    duration: "1m",
+                    target: __ENV.RAMP_TARGET
+                        ? parseInt(__ENV.RAMP_TARGET, 10)
+                        : 50,
+                },
+                {
+                    duration: "1m",
+                    target: __ENV.RAMP_TARGET
+                        ? parseInt(__ENV.RAMP_TARGET, 10)
+                        : 50,
+                },
+                { duration: "1m", target: 0 },
+            ],
+            gracefulStop: "30s",
+            startTime: "30s",
+        },
+    },
+    thresholds: {
+        http_req_failed: ["rate<0.02"], // < 2% failures
+        http_req_duration: ["p(90)<800", "p(99)<1500"], // latency SLO
+        "cart_add_item_duration{op:add}": ["p(90)<800"],
+        "cart_fetch_duration{op:get}": ["p(90)<600"],
+    },
+    summaryTrendStats: ["avg", "min", "med", "max", "p(90)", "p(95)", "p(99)"],
+};
+
+// ---------------- Metrics ----------------
+const addItemTrend = new Trend("cart_add_item_duration", true);
+const fetchTrend = new Trend("cart_fetch_duration", true);
+const checkoutTrend = new Trend("cart_checkout_duration", true);
+const addedItemsCounter = new Counter("cart_items_added");
+const checkoutCounter = new Counter("cart_checkout_calls");
+
+// ---------------- SKUs ----------------
+const SKUS = [
+    "778290",
+    "778345",
+    "778317",
+    "778277",
+    "778267",
+    "778376",
+    "778244",
+    "778384",
+    "778365",
+    "778377",
+    "778255",
+    "778286",
+    "778246",
+    "778270",
+    "778266",
+    "778285",
+    "778329",
+    "778425",
+    "778407",
+    "778418",
+    "778430",
+    "778469",
+    "778358",
+    "778351",
+    "778319",
+    "778307",
+    "778278",
+    "778251",
+    "778253",
+    "778261",
+    "778263",
+    "778273",
+    "778281",
+    "778294",
+    "778297",
+    "778302",
+];
+
+// ---------------- Helpers ----------------
+function randomSku() {
+    return SKUS[Math.floor(Math.random() * SKUS.length)];
+}
+function randomQty() {
+    return 1 + Math.floor(Math.random() * 3); // 1..3
+}
+function baseUrl() {
+    const u = __ENV.BASE_URL || "http://localhost:8080/cart";
+    // Allow user to pass either root host or full /cart path
+    return u.endsWith("/cart") ? u : u.replace(/\/+$/, "") + "/cart";
+}
+function extractCookie(res, name) {
+    const cookies = res.cookies[name];
+    if (!cookies || cookies.length === 0) return null;
+    return cookies[0].value;
+}
+function withCookies(headers, cookieJar) {
+    if (!cookieJar || Object.keys(cookieJar).length === 0) return headers;
+    const cookieStr = Object.entries(cookieJar)
+        .map(([k, v]) => `${k}=${v}`)
+        .join("; ");
+    return { ...headers, Cookie: cookieStr };
+}
+
+// Maintain cart + owner cookies per VU
+let cartState = {
+    cartid: null,
+    cartowner: null,
+};
+
+// Refresh cookies from response
+function updateCookies(res) {
+    const cid = extractCookie(res, "cartid");
+    if (cid) cartState.cartid = cid;
+    const owner = extractCookie(res, "cartowner");
+    if (owner) cartState.cartowner = owner;
+}
+
+// Build headers
+function headers() {
+    const h = { "Content-Type": "application/json" };
+    const jar = {};
+    if (cartState.cartid) jar["cartid"] = cartState.cartid;
+    if (cartState.cartowner) jar["cartowner"] = cartState.cartowner;
+    return withCookies(h, jar);
+}
+
+// Ensure cart exists (GET /)
+function ensureCart() {
+    if (cartState.cartid) return;
+    const res = http.get(baseUrl() + "/", { headers: headers() });
+    updateCookies(res);
+    check(res, {
+        "ensure cart status 200": (r) => r.status === 200,
+        "ensure cart has id": () => !!cartState.cartid,
+    });
+}
+
+// Add random item
+function addRandomItem() {
+    const payload = JSON.stringify({
+        sku: randomSku(),
+        quantity: randomQty(),
+        country: "no",
+    });
+    const start = Date.now();
+    const res = http.post(baseUrl(), payload, { headers: headers() });
+    const dur = Date.now() - start;
+    addItemTrend.add(dur, { op: "add" });
+    if (res.status === 200) {
+        addedItemsCounter.add(1);
+    }
+    updateCookies(res);
+    check(res, {
+        "add item status ok": (r) => r.status === 200,
+    });
+}
+
+// Fetch cart state
+function fetchCart() {
+    const start = Date.now();
+    const res = http.get(baseUrl() + "/", { headers: headers() });
+    const dur = Date.now() - start;
+    fetchTrend.add(dur, { op: "get" });
+    updateCookies(res);
+    check(res, { "fetch status ok": (r) => r.status === 200 });
+}
+
+// Occasional checkout trigger
+function maybeCheckout() {
+    if (!cartState.cartid) return;
+    // // Small probability
+    // if (Math.random() < 0.02) {
+    //     const start = Date.now();
+    //     const res = http.get(baseUrl() + "/checkout", { headers: headers() });
+    //     const dur = Date.now() - start;
+    //     checkoutTrend.add(dur, { op: "checkout" });
+    //     updateCookies(res);
+    //     if (res.status === 200) checkoutCounter.add(1);
+    //     check(res, { "checkout status ok": (r) => r.status === 200 });
+    // }
+}
+
+// ---------------- k6 lifecycle ----------------
+export function setup() {
+    // Provide SKU list length for summary
+    return { skuCount: SKUS.length };
+}
+
+export default function (data) {
+    group("cart flow", () => {
+        // Create or reuse cart
+        ensureCart();
+
+        // Random number of item mutations per iteration (1..5)
+        const ops = 1 + Math.floor(Math.random() * 5);
+        for (let i = 0; i < ops; i++) {
+            addRandomItem();
+        }
+
+        // Fetch state
+        fetchCart();
+
+        // Optional checkout attempt
+        maybeCheckout();
+    });
+
+    // Small think time
+    sleep(Math.random() * 0.5);
+}
+
+export function teardown(data) {
+    // Optionally we could GET confirmation or clear cart cookie
+    // Not implemented for load purpose.
+    console.log(`Test complete. SKU count: ${data.skuCount}`);
+}
+
+// ---------------- Summary ----------------
+export function handleSummary(data) {
+    return {
+        stdout: JSON.stringify(
+            {
+                metrics: {
+                    mutations_avg: data.metrics.cart_add_item_duration?.avg,
+                    mutations_p95: data.metrics.cart_add_item_duration?.p(95),
+                    fetch_p95: data.metrics.cart_fetch_duration?.p(95),
+                    checkout_count: data.metrics.cart_checkout_calls?.count,
+                },
+                checks: data.root_checks,
+            },
+            null,
+            2,
+        ),
+    };
+}

main.go

@@ -1,410 +0,0 @@
-package main
-
-import (
-	"encoding/json"
-	"fmt"
-	"log"
-	"net/http"
-	"net/http/pprof"
-	"os"
-	"os/signal"
-	"strings"
-	"syscall"
-	"time"
-
-	messages "git.tornberg.me/go-cart-actor/proto"
-	"github.com/prometheus/client_golang/prometheus"
-	"github.com/prometheus/client_golang/prometheus/promauto"
-	"github.com/prometheus/client_golang/prometheus/promhttp"
-	"k8s.io/client-go/kubernetes"
-	"k8s.io/client-go/rest"
-)
-
-var (
-	grainSpawns = promauto.NewCounter(prometheus.CounterOpts{
-		Name: "cart_grain_spawned_total",
-		Help: "The total number of spawned grains",
-	})
-	grainMutations = promauto.NewCounter(prometheus.CounterOpts{
-		Name: "cart_grain_mutations_total",
-		Help: "The total number of mutations",
-	})
-	grainLookups = promauto.NewCounter(prometheus.CounterOpts{
-		Name: "cart_grain_lookups_total",
-		Help: "The total number of lookups",
-	})
-)
-
-func spawn(id CartId) (*CartGrain, error) {
-	grainSpawns.Inc()
-	ret := &CartGrain{
-		lastItemId:     0,
-		lastDeliveryId: 0,
-		Deliveries:     []*CartDelivery{},
-		Id:             id,
-		Items:          []*CartItem{},
-		// storageMessages removed (legacy event log deprecated)
-		TotalPrice: 0,
-	}
-	err := loadMessages(ret, id)
-	return ret, err
-}
-
-func init() {
-	os.Mkdir("data", 0755)
-}
-
-type App struct {
-	pool    *GrainLocalPool
-	storage *DiskStorage
-}
-
-func (a *App) Save() error {
-	hasChanges := false
-	a.pool.mu.RLock()
-	defer a.pool.mu.RUnlock()
-	for id, grain := range a.pool.GetGrains() {
-		if grain == nil {
-			continue
-		}
-		if grain.GetLastChange() > a.storage.LastSaves[id] {
-			hasChanges = true
-			err := a.storage.Store(id, grain)
-			if err != nil {
-				log.Printf("Error saving grain %s: %v\n", id, err)
-			}
-		}
-	}
-
-	if !hasChanges {
-		return nil
-	}
-	return a.storage.saveState()
-}
-
-func (a *App) HandleSave(w http.ResponseWriter, r *http.Request) {
-	err := a.Save()
-	if err != nil {
-		w.WriteHeader(http.StatusInternalServerError)
-		w.Write([]byte(err.Error()))
-	} else {
-		w.WriteHeader(http.StatusCreated)
-	}
-}
-
-var podIp = os.Getenv("POD_IP")
-var name = os.Getenv("POD_NAME")
-var amqpUrl = os.Getenv("AMQP_URL")
-var KlarnaInstance = NewKlarnaClient(KlarnaPlaygroundUrl, os.Getenv("KLARNA_API_USERNAME"), os.Getenv("KLARNA_API_PASSWORD"))
-
-var tpl = `<!DOCTYPE html>
-<html lang="en">
-  <head>
-    <meta charset="UTF-8" />
-    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
-    <title>s10r testing - checkout</title>
-  </head>
-
-  <body>
-    %s
-  </body>
-</html>
-`
-
-func getCountryFromHost(host string) string {
-	if strings.Contains(strings.ToLower(host), "-no") {
-		return "no"
-	}
-	return "se"
-}
-
-func getCheckoutOrder(host string, cartId CartId) *messages.CreateCheckoutOrder {
-	baseUrl := fmt.Sprintf("https://%s", host)
-	cartBaseUrl := os.Getenv("CART_BASE_URL")
-	if cartBaseUrl == "" {
-		cartBaseUrl = "https://cart.tornberg.me"
-	}
-	country := getCountryFromHost(host)
-
-	return &messages.CreateCheckoutOrder{
-		Terms:        fmt.Sprintf("%s/terms", baseUrl),
-		Checkout:     fmt.Sprintf("%s/checkout?order_id={checkout.order.id}", baseUrl),
-		Confirmation: fmt.Sprintf("%s/confirmation/{checkout.order.id}", baseUrl),
-		Validation:   fmt.Sprintf("%s/validation", cartBaseUrl),
-		Push:         fmt.Sprintf("%s/push?order_id={checkout.order.id}", cartBaseUrl),
-		Country:      country,
-	}
-}
-
-func GetDiscovery() Discovery {
-	if podIp == "" {
-		return nil
-	}
-
-	config, kerr := rest.InClusterConfig()
-
-	if kerr != nil {
-		log.Fatalf("Error creating kubernetes client: %v\n", kerr)
-	}
-	client, err := kubernetes.NewForConfig(config)
-	if err != nil {
-		log.Fatalf("Error creating client: %v\n", err)
-	}
-	return NewK8sDiscovery(client)
-}
-
-func main() {
-
-	storage, err := NewDiskStorage(fmt.Sprintf("data/%s_state.gob", name))
-	if err != nil {
-		log.Printf("Error loading state: %v\n", err)
-	}
-	app := &App{
-		pool:    NewGrainLocalPool(65535, 5*time.Minute, spawn),
-		storage: storage,
-	}
-
-	syncedPool, err := NewSyncedPool(app.pool, podIp, GetDiscovery())
-	if err != nil {
-		log.Fatalf("Error creating synced pool: %v\n", err)
-	}
-
-	// Start unified gRPC server (CartActor + ControlPlane) replacing legacy RPC server on :1337
-	// TODO: Remove any remaining legacy RPC server references and deprecated frame-based code after full gRPC migration is validated.
-	grpcSrv, err := StartGRPCServer(":1337", app.pool, syncedPool)
-	if err != nil {
-		log.Fatalf("Error starting gRPC server: %v\n", err)
-	}
-	defer grpcSrv.GracefulStop()
-
-	go func() {
-		for range time.Tick(time.Minute * 10) {
-			err := app.Save()
-			if err != nil {
-				log.Printf("Error saving: %v\n", err)
-			}
-		}
-	}()
-	orderHandler := &AmqpOrderHandler{
-		Url: amqpUrl,
-	}
-
-	syncedServer := NewPoolServer(syncedPool, fmt.Sprintf("%s, %s", name, podIp))
-	mux := http.NewServeMux()
-	mux.Handle("/cart/", http.StripPrefix("/cart", syncedServer.Serve()))
-	// only for local
-	// mux.HandleFunc("GET /add/remote/{host}", func(w http.ResponseWriter, r *http.Request) {
-	// 	syncedPool.AddRemote(r.PathValue("host"))
-	// })
-	// mux.HandleFunc("GET /save", app.HandleSave)
-	//mux.HandleFunc("/", app.RewritePath)
-	mux.HandleFunc("/debug/pprof/", pprof.Index)
-	mux.HandleFunc("/debug/pprof/cmdline", pprof.Cmdline)
-	mux.HandleFunc("/debug/pprof/profile", pprof.Profile)
-	mux.HandleFunc("/debug/pprof/symbol", pprof.Symbol)
-	mux.HandleFunc("/debug/pprof/trace", pprof.Trace)
-	mux.Handle("/metrics", promhttp.Handler())
-	mux.HandleFunc("/healthz", func(w http.ResponseWriter, r *http.Request) {
-		// Grain pool health: simple capacity check (mirrors previous GrainHandler.IsHealthy)
-		app.pool.mu.RLock()
-		grainCount := len(app.pool.grains)
-		capacity := app.pool.PoolSize
-		app.pool.mu.RUnlock()
-		if grainCount >= capacity {
-			w.WriteHeader(http.StatusInternalServerError)
-			w.Write([]byte("grain pool at capacity"))
-			return
-		}
-		if !syncedPool.IsHealthy() {
-			w.WriteHeader(http.StatusInternalServerError)
-			w.Write([]byte("control plane not healthy"))
-			return
-		}
-		w.WriteHeader(http.StatusOK)
-		w.Write([]byte("ok"))
-	})
-	mux.HandleFunc("/readyz", func(w http.ResponseWriter, r *http.Request) {
-		w.WriteHeader(http.StatusOK)
-		w.Write([]byte("ok"))
-	})
-	mux.HandleFunc("/livez", func(w http.ResponseWriter, r *http.Request) {
-		w.WriteHeader(http.StatusOK)
-		w.Write([]byte("ok"))
-	})
-
-	mux.HandleFunc("/checkout", func(w http.ResponseWriter, r *http.Request) {
-		orderId := r.URL.Query().Get("order_id")
-		order := &CheckoutOrder{}
-
-		if orderId == "" {
-			cookie, err := r.Cookie("cartid")
-			if err != nil {
-				w.WriteHeader(http.StatusBadRequest)
-				w.Write([]byte(err.Error()))
-				return
-			}
-			if cookie.Value == "" {
-				w.WriteHeader(http.StatusBadRequest)
-				w.Write([]byte("no cart id to checkout is empty"))
-				return
-			}
-			cartId := ToCartId(cookie.Value)
-			order, err = syncedServer.CreateOrUpdateCheckout(r.Host, cartId)
-			if err != nil {
-				w.WriteHeader(http.StatusInternalServerError)
-				w.Write([]byte(err.Error()))
-			}
-			// v2: Apply now returns *CartGrain; order creation handled inside grain (no payload to unmarshal)
-		} else {
-			order, err = KlarnaInstance.GetOrder(orderId)
-			if err != nil {
-				w.WriteHeader(http.StatusBadRequest)
-				w.Write([]byte(err.Error()))
-				return
-			}
-
-		}
-		w.Header().Set("Content-Type", "text/html; charset=utf-8")
-		w.Header().Set("Permissions-Policy", "payment=(self \"https://js.stripe.com\" \"https://m.stripe.network\" \"https://js.playground.kustom.co\")")
-		w.WriteHeader(http.StatusOK)
-		w.Write([]byte(fmt.Sprintf(tpl, order.HTMLSnippet)))
-	})
-	mux.HandleFunc("/confirmation/{order_id}", func(w http.ResponseWriter, r *http.Request) {
-
-		orderId := r.PathValue("order_id")
-		order, err := KlarnaInstance.GetOrder(orderId)
-
-		if err != nil {
-			w.WriteHeader(http.StatusInternalServerError)
-			w.Write([]byte(err.Error()))
-			return
-		}
-
-		w.Header().Set("Content-Type", "text/html; charset=utf-8")
-		if order.Status == "checkout_complete" {
-			http.SetCookie(w, &http.Cookie{
-				Name:     "cartid",
-				Value:    "",
-				Path:     "/",
-				Secure:   true,
-				HttpOnly: true,
-				Expires:  time.Unix(0, 0),
-				SameSite: http.SameSiteLaxMode,
-			})
-		}
-
-		w.WriteHeader(http.StatusOK)
-		w.Write([]byte(fmt.Sprintf(tpl, order.HTMLSnippet)))
-	})
-	mux.HandleFunc("/validate", func(w http.ResponseWriter, r *http.Request) {
-		log.Printf("Klarna order validation, method: %s", r.Method)
-		if r.Method != "POST" {
-			w.WriteHeader(http.StatusMethodNotAllowed)
-			return
-		}
-		order := &CheckoutOrder{}
-		err := json.NewDecoder(r.Body).Decode(order)
-		if err != nil {
-			w.WriteHeader(http.StatusBadRequest)
-		}
-		log.Printf("Klarna order validation: %s", order.ID)
-		//err = confirmOrder(order, orderHandler)
-		//if err != nil {
-		//	log.Printf("Error validating order: %v\n", err)
-		//	w.WriteHeader(http.StatusInternalServerError)
-		//	return
-		//}
-		//
-		//err = triggerOrderCompleted(err, syncedServer, order)
-		//if err != nil {
-		//	log.Printf("Error processing cart message: %v\n", err)
-		//	w.WriteHeader(http.StatusInternalServerError)
-		//	return
-		//}
-		w.WriteHeader(http.StatusOK)
-	})
-	mux.HandleFunc("/push", func(w http.ResponseWriter, r *http.Request) {
-
-		if r.Method != http.MethodPost {
-			w.WriteHeader(http.StatusMethodNotAllowed)
-			return
-		}
-		orderId := r.URL.Query().Get("order_id")
-		log.Printf("Order confirmation push: %s", orderId)
-
-		order, err := KlarnaInstance.GetOrder(orderId)
-
-		if err != nil {
-			log.Printf("Error creating request: %v\n", err)
-			w.WriteHeader(http.StatusInternalServerError)
-			return
-		}
-
-		err = confirmOrder(order, orderHandler)
-		if err != nil {
-			log.Printf("Error confirming order: %v\n", err)
-			w.WriteHeader(http.StatusInternalServerError)
-			return
-		}
-
-		err = triggerOrderCompleted(err, syncedServer, order)
-		if err != nil {
-			log.Printf("Error processing cart message: %v\n", err)
-			w.WriteHeader(http.StatusInternalServerError)
-			return
-		}
-		err = KlarnaInstance.AcknowledgeOrder(orderId)
-		if err != nil {
-			log.Printf("Error acknowledging order: %v\n", err)
-		}
-
-		w.WriteHeader(http.StatusOK)
-	})
-	mux.HandleFunc("/version", func(w http.ResponseWriter, r *http.Request) {
-		w.WriteHeader(http.StatusOK)
-		w.Write([]byte("1.0.0"))
-	})
-
-	sigs := make(chan os.Signal, 1)
-	done := make(chan bool, 1)
-	signal.Notify(sigs, syscall.SIGTERM)
-
-	go func() {
-		sig := <-sigs
-		fmt.Println("Shutting down due to signal:", sig)
-		go syncedPool.Close()
-		app.Save()
-		done <- true
-	}()
-
-	log.Print("Server started at port 8080")
-	go http.ListenAndServe(":8080", mux)
-	<-done
-
-}
-
-func triggerOrderCompleted(err error, syncedServer *PoolServer, order *CheckoutOrder) error {
-	_, err = syncedServer.pool.Apply(ToCartId(order.MerchantReference1), &messages.OrderCreated{
-		OrderId: order.ID,
-		Status:  order.Status,
-	})
-	return err
-}
-
-func confirmOrder(order *CheckoutOrder, orderHandler *AmqpOrderHandler) error {
-	orderToSend, err := json.Marshal(order)
-	if err != nil {
-		return err
-	}
-	err = orderHandler.Connect()
-	if err != nil {
-		return err
-	}
-	defer orderHandler.Close()
-	err = orderHandler.OrderCompleted(orderToSend)
-	if err != nil {
-		return err
-	}
-
-	return nil
-}

multi_node_ownership_test.go

@@ -1,182 +0,0 @@
-package main
-
-import (
-	"context"
-	"fmt"
-	"testing"
-	"time"
-
-	messages "git.tornberg.me/go-cart-actor/proto"
-	"google.golang.org/grpc"
-)
-
-// TestMultiNodeOwnershipNegotiation spins up two gRPC servers (nodeA, nodeB),
-// manually links their SyncedPools (bypassing AddRemote's fixed port assumption),
-// and verifies that only one node becomes the owner of a new cart while the
-// other can still apply a mutation via the remote proxy path.
-//
-// NOTE:
-//   - We manually inject RemoteHostGRPC entries because AddRemote() hard-codes
-//     port 1337; to run two distinct servers concurrently we need distinct ports.
-//   - This test asserts single ownership consistency rather than the complete
-//     quorum semantics (which depend on real discovery + AddRemote).
-func TestMultiNodeOwnershipNegotiation(t *testing.T) {
-	// Allocate distinct ports for the two nodes.
-	const (
-		addrA = "127.0.0.1:18081"
-		addrB = "127.0.0.1:18082"
-		hostA = "nodeA"
-		hostB = "nodeB"
-	)
-
-	// Create local grain pools.
-	poolA := NewGrainLocalPool(1024, time.Minute, spawn)
-	poolB := NewGrainLocalPool(1024, time.Minute, spawn)
-
-	// Create synced pools (no discovery).
-	syncedA, err := NewSyncedPool(poolA, hostA, nil)
-	if err != nil {
-		t.Fatalf("nodeA NewSyncedPool error: %v", err)
-	}
-	syncedB, err := NewSyncedPool(poolB, hostB, nil)
-	if err != nil {
-		t.Fatalf("nodeB NewSyncedPool error: %v", err)
-	}
-
-	// Start gRPC servers (CartActor + ControlPlane) on different ports.
-	grpcSrvA, err := StartGRPCServer(addrA, poolA, syncedA)
-	if err != nil {
-		t.Fatalf("StartGRPCServer A error: %v", err)
-	}
-	defer grpcSrvA.GracefulStop()
-
-	grpcSrvB, err := StartGRPCServer(addrB, poolB, syncedB)
-	if err != nil {
-		t.Fatalf("StartGRPCServer B error: %v", err)
-	}
-	defer grpcSrvB.GracefulStop()
-
-	// Helper to connect one pool to the other's server (manual AddRemote equivalent).
-	link := func(src *SyncedPool, remoteHost, remoteAddr string) {
-		ctx, cancel := context.WithTimeout(context.Background(), 3*time.Second)
-		defer cancel()
-		conn, dialErr := grpc.DialContext(ctx, remoteAddr, grpc.WithInsecure(), grpc.WithBlock())
-		if dialErr != nil {
-			t.Fatalf("dial %s (%s) failed: %v", remoteHost, remoteAddr, dialErr)
-		}
-		cartClient := messages.NewCartActorClient(conn)
-		controlClient := messages.NewControlPlaneClient(conn)
-
-		src.mu.Lock()
-		src.remoteHosts[remoteHost] = &RemoteHostGRPC{
-			Host:          remoteHost,
-			Conn:          conn,
-			CartClient:    cartClient,
-			ControlClient: controlClient,
-		}
-		src.mu.Unlock()
-	}
-
-	// Cross-link the two pools.
-	link(syncedA, hostB, addrB)
-	link(syncedB, hostA, addrA)
-
-	// Rebuild rings after manual cross-link so deterministic ownership works immediately.
-	syncedA.ForceRingRefresh()
-	syncedB.ForceRingRefresh()
-
-	// Allow brief stabilization (control plane pings / no real negotiation needed here).
-	time.Sleep(200 * time.Millisecond)
-
-	// Create a deterministic cart id for test readability.
-	cartID := ToCartId(fmt.Sprintf("cart-%d", time.Now().UnixNano()))
-
-	// Mutation payload (ring-determined ownership; no assumption about which node owns).
-	addItem := &messages.AddItem{
-		ItemId:   1,
-		Quantity: 1,
-		Price:    1500,
-		OrgPrice: 1500,
-		Sku:      "sku-test-multi",
-		Name:     "Multi Node Test",
-		Image:    "/test.png",
-		Stock:    2,
-		Tax:      2500,
-		Country:  "se",
-	}
-
-	// Determine ring owner and set primary / secondary references.
-	ownerHost := syncedA.DebugOwnerHost(cartID)
-	var ownerSynced, otherSynced *SyncedPool
-	var ownerPool, otherPool *GrainLocalPool
-	switch ownerHost {
-	case hostA:
-		ownerSynced, ownerPool = syncedA, poolA
-		otherSynced, otherPool = syncedB, poolB
-	case hostB:
-		ownerSynced, ownerPool = syncedB, poolB
-		otherSynced, otherPool = syncedA, poolA
-	default:
-		t.Fatalf("unexpected ring owner %s (expected %s or %s)", ownerHost, hostA, hostB)
-	}
-
-	// Apply mutation on the ring-designated owner.
-	if _, err := ownerSynced.Apply(cartID, addItem); err != nil {
-		t.Fatalf("owner %s Apply addItem error: %v", ownerHost, err)
-	}
-
-	// Validate owner pool has the grain and the other does not.
-	if _, ok := ownerPool.GetGrains()[cartID]; !ok {
-		t.Fatalf("expected owner %s to have local grain", ownerHost)
-	}
-	if _, ok := otherPool.GetGrains()[cartID]; ok {
-		t.Fatalf("non-owner unexpectedly holds local grain")
-	}
-
-	// Prepare change mutation to be applied from the non-owner (should route remotely).
-	change := &messages.ChangeQuantity{
-		Id:       1, // line id after first AddItem
-		Quantity: 2,
-	}
-	// Apply remotely via the non-owner.
-	if _, err := otherSynced.Apply(cartID, change); err != nil {
-		t.Fatalf("non-owner remote Apply changeQuantity error: %v", err)
-	}
-
-	// Remote re-mutation already performed via otherSynced; removed duplicate block.
-
-	// NodeB local grain assertion:
-	// Only assert absence if nodeB is NOT the ring-designated owner. If nodeB is the owner,
-	// it is expected to have a local grain (previous generic ownership assertions already ran).
-	if ownerHost != hostB {
-		if _, local := poolB.GetGrains()[cartID]; local {
-			t.Fatalf("nodeB unexpectedly created local grain (ownership duplication)")
-		}
-	}
-
-	// Fetch state from nodeB to ensure we see updated quantity (2).
-	grainStateB, err := syncedB.Get(cartID)
-	if err != nil {
-		t.Fatalf("nodeB Get error: %v", err)
-	}
-	if len(grainStateB.Items) != 1 || grainStateB.Items[0].Quantity != 2 {
-		t.Fatalf("nodeB observed inconsistent state: items=%d qty=%d (expected 1 / 2)",
-			len(grainStateB.Items),
-			func() int {
-				if len(grainStateB.Items) == 0 {
-					return -1
-				}
-				return grainStateB.Items[0].Quantity
-			}(),
-		)
-	}
-
-	// Cross-check from nodeA (authoritative) to ensure state matches.
-	grainStateA, err := syncedA.Get(cartID)
-	if err != nil {
-		t.Fatalf("nodeA Get error: %v", err)
-	}
-	if grainStateA.Items[0].Quantity != 2 {
-		t.Fatalf("nodeA authoritative state mismatch: expected qty=2 got %d", grainStateA.Items[0].Quantity)
-	}
-}

multi_node_three_test.go

@@ -1,304 +0,0 @@
-package main
-
-import (
-	"context"
-	"fmt"
-	"testing"
-	"time"
-
-	messages "git.tornberg.me/go-cart-actor/proto"
-	"google.golang.org/grpc"
-)
-
-// TestThreeNodeMajorityOwnership validates ring-determined ownership and routing
-// in a 3-node cluster (A,B,C) using the consistent hashing ring (no quorum RPC).
-// The previous ConfirmOwner / quorum semantics have been removed; ownership is
-// deterministic and derived from the ring.
-//
-// It validates:
-//  1. The ring selects exactly one primary owner for a new cart.
-//  2. Other nodes (B,C) do NOT create local grains for the cart.
-//  3. Remote proxies are installed lazily so remote mutations can route.
-//  4. A remote mutation from one non-owner updates state visible on another.
-//  5. Authoritative state on the owner matches remote observations.
-//  6. (Future) This scaffolds replication tests when RF>1 is enabled.
-//
-// (Legacy comments about ConfirmOwner acceptance thresholds have been removed.)
-// (Function name retained for historical continuity.)
-func TestThreeNodeMajorityOwnership(t *testing.T) {
-	const (
-		addrA = "127.0.0.1:18181"
-		addrB = "127.0.0.1:18182"
-		addrC = "127.0.0.1:18183"
-		hostA = "nodeA3"
-		hostB = "nodeB3"
-		hostC = "nodeC3"
-	)
-
-	// Local grain pools
-	poolA := NewGrainLocalPool(1024, time.Minute, spawn)
-	poolB := NewGrainLocalPool(1024, time.Minute, spawn)
-	poolC := NewGrainLocalPool(1024, time.Minute, spawn)
-
-	// Synced pools (no discovery)
-	syncedA, err := NewSyncedPool(poolA, hostA, nil)
-	if err != nil {
-		t.Fatalf("nodeA NewSyncedPool error: %v", err)
-	}
-	syncedB, err := NewSyncedPool(poolB, hostB, nil)
-	if err != nil {
-		t.Fatalf("nodeB NewSyncedPool error: %v", err)
-	}
-	syncedC, err := NewSyncedPool(poolC, hostC, nil)
-	if err != nil {
-		t.Fatalf("nodeC NewSyncedPool error: %v", err)
-	}
-
-	// Start gRPC servers
-	grpcSrvA, err := StartGRPCServer(addrA, poolA, syncedA)
-	if err != nil {
-		t.Fatalf("StartGRPCServer A error: %v", err)
-	}
-	defer grpcSrvA.GracefulStop()
-	grpcSrvB, err := StartGRPCServer(addrB, poolB, syncedB)
-	if err != nil {
-		t.Fatalf("StartGRPCServer B error: %v", err)
-	}
-	defer grpcSrvB.GracefulStop()
-	grpcSrvC, err := StartGRPCServer(addrC, poolC, syncedC)
-	if err != nil {
-		t.Fatalf("StartGRPCServer C error: %v", err)
-	}
-	defer grpcSrvC.GracefulStop()
-
-	// Helper for manual cross-link (since AddRemote assumes fixed port)
-	link := func(src *SyncedPool, remoteHost, remoteAddr string) {
-		ctx, cancel := context.WithTimeout(context.Background(), 3*time.Second)
-		defer cancel()
-		conn, dialErr := grpc.DialContext(ctx, remoteAddr, grpc.WithInsecure(), grpc.WithBlock())
-		if dialErr != nil {
-			t.Fatalf("dial %s (%s) failed: %v", remoteHost, remoteAddr, dialErr)
-		}
-		cartClient := messages.NewCartActorClient(conn)
-		controlClient := messages.NewControlPlaneClient(conn)
-
-		src.mu.Lock()
-		src.remoteHosts[remoteHost] = &RemoteHostGRPC{
-			Host:          remoteHost,
-			Conn:          conn,
-			CartClient:    cartClient,
-			ControlClient: controlClient,
-		}
-		src.mu.Unlock()
-	}
-
-	// Full mesh (each node knows all others)
-	link(syncedA, hostB, addrB)
-	link(syncedA, hostC, addrC)
-
-	link(syncedB, hostA, addrA)
-	link(syncedB, hostC, addrC)
-
-	link(syncedC, hostA, addrA)
-	link(syncedC, hostB, addrB)
-
-	// Rebuild rings after manual linking so ownership resolution is immediate.
-	syncedA.ForceRingRefresh()
-	syncedB.ForceRingRefresh()
-	syncedC.ForceRingRefresh()
-
-	// Allow brief stabilization
-	time.Sleep(200 * time.Millisecond)
-
-	// Deterministic-ish cart id
-	cartID := ToCartId(fmt.Sprintf("cart3-%d", time.Now().UnixNano()))
-
-	addItem := &messages.AddItem{
-		ItemId:   10,
-		Quantity: 1,
-		Price:    5000,
-		OrgPrice: 5000,
-		Sku:      "sku-3node",
-		Name:     "Three Node Test",
-		Image:    "/t.png",
-		Stock:    10,
-		Tax:      2500,
-		Country:  "se",
-	}
-
-	// Determine ring-designated owner (may be any of the three hosts)
-	ownerPre := syncedA.DebugOwnerHost(cartID)
-	if ownerPre != hostA && ownerPre != hostB && ownerPre != hostC {
-		t.Fatalf("ring returned unexpected owner %s (not in set {%s,%s,%s})", ownerPre, hostA, hostB, hostC)
-	}
-	var ownerSynced *SyncedPool
-	var ownerPool *GrainLocalPool
-	switch ownerPre {
-	case hostA:
-		ownerSynced, ownerPool = syncedA, poolA
-	case hostB:
-		ownerSynced, ownerPool = syncedB, poolB
-	case hostC:
-		ownerSynced, ownerPool = syncedC, poolC
-	}
-	// Pick two distinct non-owner nodes for remote mutation assertions
-	var remote1Synced, remote2Synced *SyncedPool
-	switch ownerPre {
-	case hostA:
-		remote1Synced, remote2Synced = syncedB, syncedC
-	case hostB:
-		remote1Synced, remote2Synced = syncedA, syncedC
-	case hostC:
-		remote1Synced, remote2Synced = syncedA, syncedB
-	}
-
-	// Apply on the ring-designated owner
-	if _, err := ownerSynced.Apply(cartID, addItem); err != nil {
-		t.Fatalf("owner %s Apply addItem error: %v", ownerPre, err)
-	}
-
-	// Small wait for remote proxy spawn (ring ownership already deterministic)
-	time.Sleep(150 * time.Millisecond)
-
-	// Assert only nodeA has local grain
-	localCount := 0
-	if _, ok := poolA.GetGrains()[cartID]; ok {
-		localCount++
-	}
-	if _, ok := poolB.GetGrains()[cartID]; ok {
-		localCount++
-	}
-	if _, ok := poolC.GetGrains()[cartID]; ok {
-		localCount++
-	}
-	if localCount != 1 {
-		t.Fatalf("expected exactly 1 local grain, got %d", localCount)
-	}
-	if _, ok := ownerPool.GetGrains()[cartID]; !ok {
-		t.Fatalf("expected owner %s to hold local grain", ownerPre)
-	}
-
-	// Remote proxies may not pre-exist; first remote mutation will trigger SpawnRemoteGrain lazily.
-
-	// Issue remote mutation from one non-owner -> ChangeQuantity (increase)
-	change := &messages.ChangeQuantity{
-		Id:       1,
-		Quantity: 3,
-	}
-	if _, err := remote1Synced.Apply(cartID, change); err != nil {
-		t.Fatalf("remote mutation (remote1) changeQuantity error: %v", err)
-	}
-
-	// Validate updated state visible via nodeC
-	stateC, err := remote2Synced.Get(cartID)
-	if err != nil {
-		t.Fatalf("nodeC Get error: %v", err)
-	}
-	if len(stateC.Items) != 1 || stateC.Items[0].Quantity != 3 {
-		t.Fatalf("nodeC observed state mismatch: items=%d qty=%d (expected 1 / 3)",
-			len(stateC.Items),
-			func() int {
-				if len(stateC.Items) == 0 {
-					return -1
-				}
-				return stateC.Items[0].Quantity
-			}(),
-		)
-	}
-
-	// Cross-check authoritative nodeA
-	stateA, err := syncedA.Get(cartID)
-	if err != nil {
-		t.Fatalf("nodeA Get error: %v", err)
-	}
-	if stateA.Items[0].Quantity != 3 {
-		t.Fatalf("nodeA authoritative state mismatch: expected qty=3 got %d", stateA.Items[0].Quantity)
-	}
-}
-
-// TestThreeNodeDiscoveryMajorityOwnership (placeholder)
-// This test is a scaffold demonstrating how a MockDiscovery would be wired
-// once AddRemote supports host:port (currently hard-coded to :1337).
-// It is skipped to avoid flakiness / false negatives until the production
-// AddRemote logic is enhanced to parse dynamic ports or the test harness
-// provides consistent port mapping.
-func TestThreeNodeDiscoveryMajorityOwnership(t *testing.T) {
-	t.Skip("Pending enhancement: AddRemote needs host:port support to fully exercise discovery-based multi-node linking")
-	// Example skeleton (non-functional with current AddRemote implementation):
-	//
-	// md := NewMockDiscovery([]string{"nodeB3", "nodeC3"})
-	// poolA := NewGrainLocalPool(1024, time.Minute, spawn)
-	// syncedA, err := NewSyncedPool(poolA, "nodeA3", md)
-	// if err != nil {
-	//     t.Fatalf("NewSyncedPool with mock discovery error: %v", err)
-	// }
-	// // Start server for nodeA (would also need servers for nodeB3/nodeC3 on expected ports)
-	// // grpcSrvA, _ := StartGRPCServer(":1337", poolA, syncedA)
-	// // defer grpcSrvA.GracefulStop()
-	//
-	// // Dynamically add a host via discovery
-	// // md.AddHost("nodeB3")
-	// // time.Sleep(100 * time.Millisecond) // allow AddRemote attempt
-	//
-	// // Assertions would verify syncedA.remoteHosts contains "nodeB3"
-}
-
-// TestHostRemovalAndErrorWithMockDiscovery validates behavior when:
-// 1. Discovery reports a host that cannot be dialed (AddRemote error path)
-// 2. That host is then removed (Deleted event) without leaving residual state
-// 3. A second failing host is added afterward (ensuring watcher still processes events)
-//
-// NOTE: Because AddRemote currently hard-codes :1337 and we are NOT starting a
-// real server for the bogus hosts, the dial will fail and the remote host should
-// never appear in remoteHosts. This intentionally exercises the error logging
-// path: "AddRemote: dial ... failed".
-func TestHostRemovalAndErrorWithMockDiscovery(t *testing.T) {
-	// Start a real node A (acts as the observing node)
-	const addrA = "127.0.0.1:18281"
-	hostA := "nodeA-md"
-
-	poolA := NewGrainLocalPool(128, time.Minute, spawn)
-
-	// Mock discovery starts with one bogus host that will fail to connect.
-	md := NewMockDiscovery([]string{"bogus-host-1"})
-	syncedA, err := NewSyncedPool(poolA, hostA, md)
-	if err != nil {
-		t.Fatalf("NewSyncedPool error: %v", err)
-	}
-
-	grpcSrvA, err := StartGRPCServer(addrA, poolA, syncedA)
-	if err != nil {
-		t.Fatalf("StartGRPCServer A error: %v", err)
-	}
-	defer grpcSrvA.GracefulStop()
-
-	// Kick off watch processing by starting Watch() (NewSyncedPool does this internally
-	// when discovery is non-nil, but we ensure events channel is active).
-	// The initial bogus host should trigger AddRemote -> dial failure.
-	time.Sleep(300 * time.Millisecond)
-
-	syncedA.mu.RLock()
-	if len(syncedA.remoteHosts) != 0 {
-		syncedA.mu.RUnlock()
-		t.Fatalf("expected 0 remoteHosts after failing dial, got %d", len(syncedA.remoteHosts))
-	}
-	syncedA.mu.RUnlock()
-
-	// Remove the bogus host (should not panic; no entry to clean up).
-	md.RemoveHost("bogus-host-1")
-	time.Sleep(100 * time.Millisecond)
-
-	// Add another bogus host to ensure watcher still alive.
-	md.AddHost("bogus-host-2")
-	time.Sleep(300 * time.Millisecond)
-
-	syncedA.mu.RLock()
-	if len(syncedA.remoteHosts) != 0 {
-		syncedA.mu.RUnlock()
-		t.Fatalf("expected 0 remoteHosts after second failing dial, got %d", len(syncedA.remoteHosts))
-	}
-	syncedA.mu.RUnlock()
-
-	// Clean up discovery
-	md.Close()
-}

mutation_add_item.go

@@ -1,82 +0,0 @@
-package main
-
-import (
-	"fmt"
-
-	messages "git.tornberg.me/go-cart-actor/proto"
-)
-
-// mutation_add_item.go
-//
-// Registers the AddItem cart mutation in the generic mutation registry.
-// This replaces the legacy switch-based logic previously found in CartGrain.Apply.
-//
-// Behavior:
-//   * Validates quantity > 0
-//   * If an item with same SKU exists -> increases quantity
-//   * Else creates a new CartItem with computed tax amounts
-//   * Totals recalculated automatically via WithTotals()
-//
-// NOTE: Any future field additions in messages.AddItem that affect pricing / tax
-// must keep this handler in sync.
-
-func init() {
-	RegisterMutation[messages.AddItem](
-		"AddItem",
-		func(g *CartGrain, m *messages.AddItem) error {
-			if m == nil {
-				return fmt.Errorf("AddItem: nil payload")
-			}
-			if m.Quantity < 1 {
-				return fmt.Errorf("AddItem: invalid quantity %d", m.Quantity)
-			}
-
-			// Fast path: merge with existing item having same SKU
-			if existing, found := g.FindItemWithSku(m.Sku); found {
-				existing.Quantity += int(m.Quantity)
-				return nil
-			}
-
-			g.mu.Lock()
-			defer g.mu.Unlock()
-
-			g.lastItemId++
-			taxRate := 2500
-			if m.Tax > 0 {
-				taxRate = int(m.Tax)
-			}
-			taxAmountPerUnit := GetTaxAmount(m.Price, taxRate)
-
-			g.Items = append(g.Items, &CartItem{
-				Id:          g.lastItemId,
-				ItemId:      int(m.ItemId),
-				Quantity:    int(m.Quantity),
-				Sku:         m.Sku,
-				Name:        m.Name,
-				Price:       m.Price,
-				TotalPrice:  m.Price * int64(m.Quantity),
-				TotalTax:    int64(taxAmountPerUnit * int64(m.Quantity)),
-				Image:       m.Image,
-				Stock:       StockStatus(m.Stock),
-				Disclaimer:  m.Disclaimer,
-				Brand:       m.Brand,
-				Category:    m.Category,
-				Category2:   m.Category2,
-				Category3:   m.Category3,
-				Category4:   m.Category4,
-				Category5:   m.Category5,
-				OrgPrice:    m.OrgPrice,
-				ArticleType: m.ArticleType,
-				Outlet:      m.Outlet,
-				SellerId:    m.SellerId,
-				SellerName:  m.SellerName,
-				Tax:         int(taxAmountPerUnit),
-				TaxRate:     taxRate,
-				StoreId:     m.StoreId,
-			})
-
-			return nil
-		},
-		WithTotals(), // Recalculate totals after successful mutation
-	)
-}

mutation_add_request.go

@@ -1,61 +0,0 @@
-package main
-
-import (
-	"fmt"
-
-	messages "git.tornberg.me/go-cart-actor/proto"
-)
-
-// mutation_add_request.go
-//
-// Registers the AddRequest mutation. This mutation is a higher-level intent
-// (add by SKU + quantity) which may translate into either:
-//   - Increasing quantity of an existing line (same SKU), OR
-//   - Creating a new item by performing a product lookup (via getItemData inside CartGrain.AddItem)
-//
-// Behavior:
-//   - Validates non-empty SKU and quantity > 0
-//   - If an item with the SKU already exists: increments its quantity
-//   - Else delegates to CartGrain.AddItem (which itself produces an AddItem mutation)
-//   - Totals recalculated automatically (WithTotals)
-//
-// NOTE:
-//   - This handler purposely avoids duplicating the detailed AddItem logic;
-//     it reuses CartGrain.AddItem which then flows through the AddItem mutation
-//     registry handler.
-//   - Double total recalculation can occur (AddItem has WithTotals too), but
-//     is acceptable for clarity. Optimize later if needed.
-//
-// Potential future improvements:
-//   - Stock validation before increasing quantity
-//   - Reservation logic or concurrency guards around stock updates
-//   - Coupon / pricing rules applied conditionally during add-by-sku
-func init() {
-	RegisterMutation[messages.AddRequest](
-		"AddRequest",
-		func(g *CartGrain, m *messages.AddRequest) error {
-			if m == nil {
-				return fmt.Errorf("AddRequest: nil payload")
-			}
-			if m.Sku == "" {
-				return fmt.Errorf("AddRequest: sku is empty")
-			}
-			if m.Quantity < 1 {
-				return fmt.Errorf("AddRequest: invalid quantity %d", m.Quantity)
-			}
-
-			// Existing line: accumulate quantity only.
-			if existing, found := g.FindItemWithSku(m.Sku); found {
-				existing.Quantity += int(m.Quantity)
-				return nil
-			}
-
-			// New line: delegate to higher-level AddItem flow (product lookup).
-			// We intentionally ignore the returned *CartGrain; registry will
-			// do totals again after this handler returns (harmless).
-			_, err := g.AddItem(m.Sku, int(m.Quantity), m.Country, m.StoreId)
-			return err
-		},
-		WithTotals(),
-	)
-}

mutation_registry.go

@@ -1,301 +0,0 @@
-package main
-
-import (
-	"fmt"
-	"reflect"
-	"sync"
-)
-
-// mutation_registry.go
-//
-// Mutation Registry Infrastructure
-// --------------------------------
-// This file introduces a generic registry for cart mutations that:
-//
-// 1. Decouples mutation logic from the large type-switch inside CartGrain.Apply.
-// 2. Enforces (at registration time) that every mutation handler has the correct
-//    signature: func(*CartGrain, *T) error
-// 3. Optionally auto-updates cart totals after a mutation if flagged.
-// 4. Provides a single authoritative list of registered mutations for
-//    introspection / coverage testing.
-// 5. Allows incremental migration: you can first register new mutations here,
-//    and later prune the legacy switch cases.
-//
-// Usage Pattern
-// -------------
-//   // Define your mutation proto message (e.g. messages.ApplyCoupon in messages.proto)
-//   // Regenerate protobufs.
-//
-//   // In an init() (ideally in a small file like mutations_apply_coupon.go)
-//   func init() {
-//       RegisterMutation[*messages.ApplyCoupon](
-//           "ApplyCoupon",
-//           func(g *CartGrain, m *messages.ApplyCoupon) error {
-//               // domain logic ...
-//               discount := int64(5000)
-//               if g.TotalPrice < discount {
-//                   discount = g.TotalPrice
-//               }
-//               g.TotalDiscount += discount
-//               g.TotalPrice -= discount
-//               return nil
-//           },
-//           WithTotals(), // we changed price-related fields; recalc totals
-//       )
-//   }
-//
-//   // To invoke dynamically (alternative to the current switch):
-//   if updated, err := ApplyRegistered(grain, incomingMessage); err == nil {
-//       grain = updated
-//   } else if errors.Is(err, ErrMutationNotRegistered) {
-//       // fallback to legacy switch logic
-//   }
-//
-// Migration Strategy
-// ------------------
-// 1. For each existing mutation handled in CartGrain.Apply, add a registry
-//    registration with equivalent logic.
-// 2. Add a test that enumerates all *expected* mutation proto types and asserts
-//    they are present in RegisteredMutationTypes().
-// 3. Once coverage is 100%, replace the switch in CartGrain.Apply with a call
-//    to ApplyRegistered (and optionally keep a minimal default to produce an
-//    "unsupported mutation" error).
-//
-// Thread Safety
-// -------------
-// Registration is typically done at init() time; a RWMutex provides safety
-// should late dynamic registration ever be introduced.
-//
-// Auto Totals
-// -----------
-// Many mutations require recomputing totals. To avoid forgetting this, pass
-// WithTotals() when registering. This will invoke grain.UpdateTotals() after
-// the handler returns successfully.
-//
-// Error Semantics
-// ---------------
-// - If a handler returns an error, totals are NOT recalculated (even if
-//   WithTotals() was specified).
-// - ApplyRegistered returns (nil, ErrMutationNotRegistered) if the message type
-//   is absent.
-//
-// Extensibility
-// -------------
-// It is straightforward to add options like audit hooks, metrics wrappers,
-// or optimistic concurrency guards by extending MutationOption.
-//
-// NOTE: Generics require Go 1.18+. If constrained to earlier Go versions,
-//       replace the generic registration with a non-generic RegisterMutationType
-//       that accepts reflect.Type and an adapter function.
-//
-// ---------------------------------------------------------------------------
-
-var (
-	mutationRegistryMu sync.RWMutex
-	mutationRegistry   = make(map[reflect.Type]*registeredMutation)
-
-	// ErrMutationNotRegistered is returned when no handler exists for a given mutation type.
-	ErrMutationNotRegistered = fmt.Errorf("mutation not registered")
-)
-
-// MutationOption configures additional behavior for a registered mutation.
-type MutationOption func(*mutationOptions)
-
-// mutationOptions holds flags adjustable per registration.
-type mutationOptions struct {
-	updateTotals bool
-}
-
-// WithTotals ensures CartGrain.UpdateTotals() is called after a successful handler.
-func WithTotals() MutationOption {
-	return func(o *mutationOptions) {
-		o.updateTotals = true
-	}
-}
-
-// registeredMutation stores metadata + the execution closure.
-type registeredMutation struct {
-	name         string
-	handler      func(*CartGrain, interface{}) error
-	updateTotals bool
-	msgType      reflect.Type
-}
-
-// RegisterMutation registers a mutation handler for a specific message type T.
-//
-// Parameters:
-//
-//	name    - a human-readable identifier (used for diagnostics / coverage tests).
-//	handler - business logic operating on the cart grain & strongly typed message.
-//	options - optional behavior flags (e.g., WithTotals()).
-//
-// Panics if:
-//   - name is empty
-//   - handler is nil
-//   - duplicate registration for the same message type T
-//
-// Typical call is placed in an init() function.
-func RegisterMutation[T any](name string, handler func(*CartGrain, *T) error, options ...MutationOption) {
-	if name == "" {
-		panic("RegisterMutation: name is required")
-	}
-	if handler == nil {
-		panic("RegisterMutation: handler is nil")
-	}
-
-	// Derive the reflect.Type for *T then its Elem (T) for mapping.
-	var zero *T
-	rtPtr := reflect.TypeOf(zero)
-	if rtPtr.Kind() != reflect.Ptr {
-		panic("RegisterMutation: expected pointer type for generic parameter")
-	}
-	rt := rtPtr.Elem()
-
-	opts := mutationOptions{}
-	for _, opt := range options {
-		opt(&opts)
-	}
-
-	wrapped := func(g *CartGrain, m interface{}) error {
-		typed, ok := m.(*T)
-		if !ok {
-			return fmt.Errorf("mutation type mismatch: have %T want *%s", m, rt.Name())
-		}
-		return handler(g, typed)
-	}
-
-	mutationRegistryMu.Lock()
-	defer mutationRegistryMu.Unlock()
-
-	if _, exists := mutationRegistry[rt]; exists {
-		panic(fmt.Sprintf("RegisterMutation: duplicate registration for type %s", rt.String()))
-	}
-
-	mutationRegistry[rt] = &registeredMutation{
-		name:         name,
-		handler:      wrapped,
-		updateTotals: opts.updateTotals,
-		msgType:      rt,
-	}
-}
-
-// ApplyRegistered attempts to apply a registered mutation.
-// Returns updated grain if successful.
-//
-// If the mutation is not registered, returns (nil, ErrMutationNotRegistered).
-func ApplyRegistered(grain *CartGrain, msg interface{}) (*CartGrain, error) {
-	if grain == nil {
-		return nil, fmt.Errorf("nil grain")
-	}
-	if msg == nil {
-		return nil, fmt.Errorf("nil mutation message")
-	}
-
-	rt := indirectType(reflect.TypeOf(msg))
-	mutationRegistryMu.RLock()
-	entry, ok := mutationRegistry[rt]
-	mutationRegistryMu.RUnlock()
-
-	if !ok {
-		return nil, ErrMutationNotRegistered
-	}
-
-	if err := entry.handler(grain, msg); err != nil {
-		return nil, err
-	}
-
-	if entry.updateTotals {
-		grain.UpdateTotals()
-	}
-
-	return grain, nil
-}
-
-// RegisteredMutations returns metadata for all registered mutations (snapshot).
-func RegisteredMutations() []string {
-	mutationRegistryMu.RLock()
-	defer mutationRegistryMu.RUnlock()
-	out := make([]string, 0, len(mutationRegistry))
-	for _, entry := range mutationRegistry {
-		out = append(out, entry.name)
-	}
-	return out
-}
-
-// RegisteredMutationTypes returns the reflect.Type list of all registered messages.
-// Useful for coverage tests ensuring expected set matches actual set.
-func RegisteredMutationTypes() []reflect.Type {
-	mutationRegistryMu.RLock()
-	defer mutationRegistryMu.RUnlock()
-	out := make([]reflect.Type, 0, len(mutationRegistry))
-	for t := range mutationRegistry {
-		out = append(out, t)
-	}
-	return out
-}
-
-// MustAssertMutationCoverage can be called at startup to ensure every expected
-// mutation type has been registered. It panics with a descriptive message if any
-// are missing. Provide a slice of prototype pointers (e.g. []*messages.AddItem{nil} ...)
-func MustAssertMutationCoverage(expected []interface{}) {
-	mutationRegistryMu.RLock()
-	defer mutationRegistryMu.RUnlock()
-
-	missing := make([]string, 0)
-	for _, ex := range expected {
-		if ex == nil {
-			continue
-		}
-		t := indirectType(reflect.TypeOf(ex))
-		if _, ok := mutationRegistry[t]; !ok {
-			missing = append(missing, t.String())
-		}
-	}
-	if len(missing) > 0 {
-		panic(fmt.Sprintf("mutation registry missing handlers for: %v", missing))
-	}
-}
-
-// indirectType returns the element type if given a pointer; otherwise the type itself.
-func indirectType(t reflect.Type) reflect.Type {
-	for t.Kind() == reflect.Ptr {
-		t = t.Elem()
-	}
-	return t
-}
-
-/*
-Integration Guide
------------------
-
-1. Register all existing mutations:
-
-   func init() {
-       RegisterMutation[*messages.AddItem]("AddItem",
-           func(g *CartGrain, m *messages.AddItem) error {
-               // (port logic from existing switch branch)
-               // ...
-               return nil
-           },
-           WithTotals(),
-       )
-       // ... repeat for others
-   }
-
-2. In CartGrain.Apply (early in the method) add:
-
-   if updated, err := ApplyRegistered(c, content); err == nil {
-       return updated, nil
-   } else if err != ErrMutationNotRegistered {
-       return nil, err
-   }
-
-   // existing switch fallback below
-
-3. Once all mutations are registered, remove the legacy switch cases
-   and leave a single ErrMutationNotRegistered path for unknown types.
-
-4. Add a coverage test (see docs for example; removed from source for clarity).
-5. (Optional) Add metrics / tracing wrappers for handlers.
-
-*/

mutation_set_cart_items.go

@@ -1,57 +0,0 @@
-package main
-
-import (
-	"fmt"
-
-	messages "git.tornberg.me/go-cart-actor/proto"
-)
-
-// mutation_set_cart_items.go
-//
-// Registers the SetCartRequest mutation. This mutation replaces the entire list
-// of cart items with the provided list (each entry is an AddRequest).
-//
-// Behavior:
-//   - Clears existing items (but leaves deliveries intact).
-//   - Iterates over each AddRequest and delegates to CartGrain.AddItem
-//     (which performs product lookup, creates AddItem mutation).
-//   - If any single addition fails, the mutation aborts with an error;
-//     items added prior to the failure remain (consistent with previous behavior).
-//   - Totals recalculated after completion via WithTotals().
-//
-// Notes:
-//   - Potential optimization: batch product lookups; currently sequential.
-//   - Consider adding rollback semantics if atomic replacement is desired.
-//   - Deliveries might reference item IDs that are now invalid—original logic
-//     also left deliveries untouched. If that becomes an issue, add a cleanup
-//     pass to remove deliveries whose item IDs no longer exist.
-func init() {
-	RegisterMutation[messages.SetCartRequest](
-		"SetCartRequest",
-		func(g *CartGrain, m *messages.SetCartRequest) error {
-			if m == nil {
-				return fmt.Errorf("SetCartRequest: nil payload")
-			}
-
-			// Clear current items (keep deliveries)
-			g.mu.Lock()
-			g.Items = make([]*CartItem, 0, len(m.Items))
-			g.mu.Unlock()
-
-			for _, it := range m.Items {
-				if it == nil {
-					continue
-				}
-				if it.Sku == "" || it.Quantity < 1 {
-					return fmt.Errorf("SetCartRequest: invalid item (sku='%s' qty=%d)", it.Sku, it.Quantity)
-				}
-				_, err := g.AddItem(it.Sku, int(it.Quantity), it.Country, it.StoreId)
-				if err != nil {
-					return fmt.Errorf("SetCartRequest: add sku '%s' failed: %w", it.Sku, err)
-				}
-			}
-			return nil
-		},
-		WithTotals(),
-	)
-}

mutation_set_delivery.go

@@ -1,101 +0,0 @@
-package main
-
-import (
-	"fmt"
-	"slices"
-
-	messages "git.tornberg.me/go-cart-actor/proto"
-)
-
-// mutation_set_delivery.go
-//
-// Registers the SetDelivery mutation.
-//
-// Semantics (mirrors legacy switch logic):
-//   - If the payload specifies an explicit list of item IDs (payload.Items):
-//   - Each referenced cart line must exist.
-//   - None of the referenced items may already belong to a delivery.
-//   - Only those items are associated with the new delivery.
-//   - If payload.Items is empty:
-//   - All items currently without any delivery are associated with the new delivery.
-//   - A new delivery line is created with:
-//   - Auto-incremented delivery ID (cart-local)
-//   - Provider from payload
-//   - Fixed price (currently hard-coded: 4900 minor units) – adjust as needed
-//   - Optional PickupPoint copied from payload
-//   - Cart totals are recalculated (WithTotals)
-//
-// Error cases:
-//   - Referenced item does not exist
-//   - Referenced item already has a delivery
-//   - No items qualify (resulting association set empty) -> returns error (prevents creating empty delivery)
-//
-// Concurrency:
-//   - Uses g.mu to protect lastDeliveryId increment and append to Deliveries slice.
-//     Item scans are read-only and performed outside the lock for simplicity;
-//     if stricter guarantees are needed, widen the lock section.
-//
-// Future extension points:
-//   - Variable delivery pricing (based on weight, distance, provider, etc.)
-//   - Validation of provider codes
-//   - Multi-currency delivery pricing
-func init() {
-	RegisterMutation[messages.SetDelivery](
-		"SetDelivery",
-		func(g *CartGrain, m *messages.SetDelivery) error {
-			if m == nil {
-				return fmt.Errorf("SetDelivery: nil payload")
-			}
-			if m.Provider == "" {
-				return fmt.Errorf("SetDelivery: provider is empty")
-			}
-
-			withDelivery := g.ItemsWithDelivery()
-			targetItems := make([]int, 0)
-
-			if len(m.Items) == 0 {
-				// Use every item currently without a delivery
-				targetItems = append(targetItems, g.ItemsWithoutDelivery()...)
-			} else {
-				// Validate explicit list
-				for _, id64 := range m.Items {
-					id := int(id64)
-					found := false
-					for _, it := range g.Items {
-						if it.Id == id {
-							found = true
-							break
-						}
-					}
-					if !found {
-						return fmt.Errorf("SetDelivery: item id %d not found", id)
-					}
-					if slices.Contains(withDelivery, id) {
-						return fmt.Errorf("SetDelivery: item id %d already has a delivery", id)
-					}
-					targetItems = append(targetItems, id)
-				}
-			}
-
-			if len(targetItems) == 0 {
-				return fmt.Errorf("SetDelivery: no eligible items to attach")
-			}
-
-			// Append new delivery
-			g.mu.Lock()
-			g.lastDeliveryId++
-			newId := g.lastDeliveryId
-			g.Deliveries = append(g.Deliveries, &CartDelivery{
-				Id:          newId,
-				Provider:    m.Provider,
-				PickupPoint: m.PickupPoint,
-				Price:       4900, // TODO: externalize pricing
-				Items:       targetItems,
-			})
-			g.mu.Unlock()
-
-			return nil
-		},
-		WithTotals(),
-	)
-}

pkg/actor/disk_storage.go

@@ -0,0 +1,139 @@
+package actor
+
+import (
+	"errors"
+	"fmt"
+	"log"
+	"os"
+	"path/filepath"
+	"sync"
+	"time"
+
+	"github.com/gogo/protobuf/proto"
+)
+
+type QueueEvent struct {
+	TimeStamp time.Time
+	Message   proto.Message
+}
+
+type DiskStorage[V any] struct {
+	*StateStorage
+	path  string
+	done  chan struct{}
+	queue *sync.Map // map[uint64][]QueueEvent
+}
+
+type LogStorage[V any] interface {
+	LoadEvents(id uint64, grain Grain[V]) error
+	AppendMutations(id uint64, msg ...proto.Message) error
+}
+
+func NewDiskStorage[V any](path string, registry MutationRegistry) *DiskStorage[V] {
+	return &DiskStorage[V]{
+		StateStorage: NewState(registry),
+		path:         path,
+		done:         make(chan struct{}),
+	}
+}
+
+func (s *DiskStorage[V]) SaveLoop(duration time.Duration) {
+	s.queue = &sync.Map{}
+	ticker := time.NewTicker(duration)
+	defer ticker.Stop()
+	for {
+		select {
+		case <-s.done:
+			s.save()
+			return
+		case <-ticker.C:
+			s.save()
+		}
+	}
+}
+
+func (s *DiskStorage[V]) save() {
+	carts := 0
+	lines := 0
+	s.queue.Range(func(key, value any) bool {
+		id := key.(uint64)
+		path := s.logPath(id)
+		fh, err := os.OpenFile(path, os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0644)
+		if err != nil {
+			log.Printf("failed to open event log file: %v", err)
+			return true
+		}
+		defer fh.Close()
+
+		if qe, ok := value.([]QueueEvent); ok {
+			for _, msg := range qe {
+				if err := s.Append(fh, msg.Message, msg.TimeStamp); err != nil {
+					log.Printf("failed to append event to log file: %v", err)
+				}
+				lines++
+			}
+		}
+		carts++
+		s.queue.Delete(id)
+		return true
+	})
+	if lines > 0 {
+		log.Printf("Appended %d carts and %d lines to disk", carts, lines)
+	}
+}
+
+func (s *DiskStorage[V]) logPath(id uint64) string {
+	return filepath.Join(s.path, fmt.Sprintf("%d.events.log", id))
+}
+
+func (s *DiskStorage[V]) LoadEvents(id uint64, grain Grain[V]) error {
+	path := s.logPath(id)
+	if _, err := os.Stat(path); errors.Is(err, os.ErrNotExist) {
+		// No log -> nothing to replay
+		return nil
+	}
+
+	fh, err := os.Open(path)
+	if err != nil {
+		return fmt.Errorf("open replay file: %w", err)
+	}
+	defer fh.Close()
+	return s.Load(fh, func(msg proto.Message) {
+		s.registry.Apply(grain, msg)
+	})
+}
+
+func (s *DiskStorage[V]) Close() {
+	if s.queue != nil {
+		s.save()
+	}
+	close(s.done)
+}
+
+func (s *DiskStorage[V]) AppendMutations(id uint64, msg ...proto.Message) error {
+	if s.queue != nil {
+		queue := make([]QueueEvent, 0)
+		data, found := s.queue.Load(id)
+		if found {
+			queue = data.([]QueueEvent)
+		}
+		for _, m := range msg {
+			queue = append(queue, QueueEvent{Message: m, TimeStamp: time.Now()})
+		}
+		s.queue.Store(id, queue)
+		return nil
+	} else {
+		path := s.logPath(id)
+		fh, err := os.OpenFile(path, os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0644)
+		if err != nil {
+			log.Printf("failed to open event log file: %v", err)
+			return err
+		}
+		defer fh.Close()
+		for _, m := range msg {
+			err = s.Append(fh, m, time.Now())
+		}
+		return err
+	}
+
+}

pkg/actor/grain.go

@@ -0,0 +1,13 @@
+package actor
+
+import (
+	"time"
+)
+
+type Grain[V any] interface {
+	GetId() uint64
+
+	GetLastAccess() time.Time
+	GetLastChange() time.Time
+	GetCurrentState() (*V, error)
+}

pkg/actor/grain_pool.go

@@ -0,0 +1,42 @@
+package actor
+
+import (
+	"net/http"
+
+	"github.com/gogo/protobuf/proto"
+)
+
+type MutationResult[V any] struct {
+	Result    V             `json:"result"`
+	Mutations []ApplyResult `json:"mutations,omitempty"`
+}
+
+type GrainPool[V any] interface {
+	Apply(id uint64, mutation ...proto.Message) (*MutationResult[V], error)
+	Get(id uint64) (V, error)
+	OwnerHost(id uint64) (Host, bool)
+	Hostname() string
+	TakeOwnership(id uint64)
+	HandleOwnershipChange(host string, ids []uint64) error
+	HandleRemoteExpiry(host string, ids []uint64) error
+	Negotiate(otherHosts []string)
+	GetLocalIds() []uint64
+	RemoveHost(host string)
+	AddRemoteHost(host string)
+	IsHealthy() bool
+	IsKnown(string) bool
+	Close()
+}
+
+// Host abstracts a remote node capable of proxying cart requests.
+type Host interface {
+	AnnounceExpiry(ids []uint64)
+	Negotiate(otherHosts []string) ([]string, error)
+	Name() string
+	Proxy(id uint64, w http.ResponseWriter, r *http.Request) (bool, error)
+	GetActorIds() []uint64
+	Close() error
+	Ping() bool
+	IsHealthy() bool
+	AnnounceOwnership(ownerHost string, ids []uint64)
+}

pkg/actor/grpc_server.go

@@ -0,0 +1,118 @@
+package actor
+
+import (
+	"context"
+	"fmt"
+	"log"
+	"net"
+	"time"
+
+	messages "git.tornberg.me/go-cart-actor/pkg/messages"
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/reflection"
+)
+
+// ControlServer implements the ControlPlane gRPC services.
+// It delegates to a grain pool and cluster operations to a synced pool.
+type ControlServer[V any] struct {
+	messages.UnimplementedControlPlaneServer
+	pool GrainPool[V]
+}
+
+func (s *ControlServer[V]) AnnounceOwnership(ctx context.Context, req *messages.OwnershipAnnounce) (*messages.OwnerChangeAck, error) {
+	err := s.pool.HandleOwnershipChange(req.Host, req.Ids)
+	if err != nil {
+		return &messages.OwnerChangeAck{
+			Accepted: false,
+			Message:  "owner change failed",
+		}, err
+	}
+
+	log.Printf("Ack count: %d", len(req.Ids))
+	return &messages.OwnerChangeAck{
+		Accepted: true,
+		Message:  "ownership announced",
+	}, nil
+}
+
+func (s *ControlServer[V]) AnnounceExpiry(ctx context.Context, req *messages.ExpiryAnnounce) (*messages.OwnerChangeAck, error) {
+	err := s.pool.HandleRemoteExpiry(req.Host, req.Ids)
+	return &messages.OwnerChangeAck{
+		Accepted: err == nil,
+		Message:  "expiry acknowledged",
+	}, nil
+}
+
+// ControlPlane: Ping
+func (s *ControlServer[V]) Ping(ctx context.Context, _ *messages.Empty) (*messages.PingReply, error) {
+	// log.Printf("got ping")
+	return &messages.PingReply{
+		Host:     s.pool.Hostname(),
+		UnixTime: time.Now().Unix(),
+	}, nil
+}
+
+// ControlPlane: Negotiate (merge host views)
+func (s *ControlServer[V]) Negotiate(ctx context.Context, req *messages.NegotiateRequest) (*messages.NegotiateReply, error) {
+
+	s.pool.Negotiate(req.KnownHosts)
+	return &messages.NegotiateReply{Hosts: req.GetKnownHosts()}, nil
+}
+
+// ControlPlane: GetCartIds (locally owned carts only)
+func (s *ControlServer[V]) GetLocalActorIds(ctx context.Context, _ *messages.Empty) (*messages.ActorIdsReply, error) {
+	return &messages.ActorIdsReply{Ids: s.pool.GetLocalIds()}, nil
+}
+
+// ControlPlane: Closing (peer shutdown notification)
+func (s *ControlServer[V]) Closing(ctx context.Context, req *messages.ClosingNotice) (*messages.OwnerChangeAck, error) {
+	if req.GetHost() != "" {
+		s.pool.RemoveHost(req.GetHost())
+	}
+	return &messages.OwnerChangeAck{
+		Accepted: true,
+		Message:  "removed host",
+	}, nil
+}
+
+type ServerConfig struct {
+	Addr    string
+	Options []grpc.ServerOption
+}
+
+func NewServerConfig(addr string, options ...grpc.ServerOption) ServerConfig {
+	return ServerConfig{
+		Addr:    addr,
+		Options: options,
+	}
+}
+
+func DefaultServerConfig() ServerConfig {
+	return NewServerConfig(":1337")
+}
+
+// StartGRPCServer configures and starts the unified gRPC server on the given address.
+// It registers both the CartActor and ControlPlane services.
+func NewControlServer[V any](config ServerConfig, pool GrainPool[V]) (*grpc.Server, error) {
+	lis, err := net.Listen("tcp", config.Addr)
+	if err != nil {
+		return nil, fmt.Errorf("failed to listen: %w", err)
+	}
+
+	grpcServer := grpc.NewServer(config.Options...)
+	server := &ControlServer[V]{
+		pool: pool,
+	}
+
+	messages.RegisterControlPlaneServer(grpcServer, server)
+	reflection.Register(grpcServer)
+
+	log.Printf("gRPC server listening as %s on %s", pool.Hostname(), config.Addr)
+	go func() {
+		if err := grpcServer.Serve(lis); err != nil {
+			log.Fatalf("failed to serve gRPC: %v", err)
+		}
+	}()
+
+	return grpcServer, nil
+}

pkg/actor/log_listerner.go

@@ -0,0 +1,47 @@
+package actor
+
+import (
+	"log"
+
+	"github.com/matst80/slask-finder/pkg/messaging"
+	amqp "github.com/rabbitmq/amqp091-go"
+)
+
+type LogListener interface {
+	AppendMutations(id uint64, msg ...ApplyResult)
+}
+
+type AmqpListener struct {
+	conn        *amqp.Connection
+	transformer func(id uint64, msg []ApplyResult) (any, error)
+}
+
+func NewAmqpListener(conn *amqp.Connection, transformer func(id uint64, msg []ApplyResult) (any, error)) *AmqpListener {
+	return &AmqpListener{
+		conn:        conn,
+		transformer: transformer,
+	}
+}
+
+func (l *AmqpListener) DefineTopics() {
+	ch, err := l.conn.Channel()
+	if err != nil {
+		log.Fatalf("Failed to open a channel: %v", err)
+	}
+	defer ch.Close()
+	if err := messaging.DefineTopic(ch, "cart", "mutation"); err != nil {
+		log.Fatalf("Failed to declare topic mutation: %v", err)
+	}
+}
+
+func (l *AmqpListener) AppendMutations(id uint64, msg ...ApplyResult) {
+	data, err := l.transformer(id, msg)
+	if err != nil {
+		log.Printf("Failed to transform mutation event: %v", err)
+		return
+	}
+	err = messaging.SendChange(l.conn, "cart", "mutation", data)
+	if err != nil {
+		log.Printf("Failed to send mutation event: %v", err)
+	}
+}

pkg/actor/mutation_registry.go

@@ -0,0 +1,267 @@
+package actor
+
+import (
+	"fmt"
+	"log"
+	"reflect"
+	"sync"
+
+	"github.com/gogo/protobuf/proto"
+)
+
+type ApplyResult struct {
+	Type     string        `json:"type"`
+	Mutation proto.Message `json:"mutation"`
+	Error    error         `json:"error,omitempty"`
+}
+
+type MutationProcessor interface {
+	Process(grain any) error
+}
+
+type BasicMutationProcessor[V any] struct {
+	processor func(any) error
+}
+
+func NewMutationProcessor[V any](process func(V) error) MutationProcessor {
+	return &BasicMutationProcessor[V]{
+		processor: func(v any) error {
+			return process(v.(V))
+		},
+	}
+}
+
+func (p *BasicMutationProcessor[V]) Process(grain any) error {
+	return p.processor(grain)
+}
+
+type MutationRegistry interface {
+	Apply(grain any, msg ...proto.Message) ([]ApplyResult, error)
+	RegisterMutations(handlers ...MutationHandler)
+	Create(typeName string) (proto.Message, bool)
+	GetTypeName(msg proto.Message) (string, bool)
+	RegisterProcessor(processor ...MutationProcessor)
+	//GetStorageEvent(msg proto.Message) StorageEvent
+	//FromStorageEvent(event StorageEvent) (proto.Message, error)
+}
+
+type ProtoMutationRegistry struct {
+	mutationRegistryMu sync.RWMutex
+	mutationRegistry   map[reflect.Type]MutationHandler
+	processors         []MutationProcessor
+}
+
+var (
+	ErrMutationNotRegistered = &MutationError{
+		Message:    "mutation not registered",
+		Code:       255,
+		StatusCode: 500,
+	}
+)
+
+type MutationError struct {
+	Message    string `json:"message"`
+	Code       uint32 `json:"code"`
+	StatusCode uint32 `json:"status_code"`
+}
+
+func (m MutationError) Error() string {
+	return m.Message
+}
+
+// MutationOption configures additional behavior for a registered mutation.
+type MutationOption func(*mutationOptions)
+
+// mutationOptions holds flags adjustable per registration.
+type mutationOptions struct {
+	updateTotals bool
+}
+
+// WithTotals ensures CartGrain.UpdateTotals() is called after a successful handler.
+func WithTotals() MutationOption {
+	return func(o *mutationOptions) {
+		o.updateTotals = true
+	}
+}
+
+type MutationHandler interface {
+	Handle(state any, msg proto.Message) error
+	Name() string
+	Type() reflect.Type
+	Create() proto.Message
+}
+
+// RegisteredMutation stores metadata + the execution closure.
+type RegisteredMutation[V any, T proto.Message] struct {
+	name    string
+	handler func(*V, T) error
+	create  func() T
+	msgType reflect.Type
+}
+
+func NewMutation[V any, T proto.Message](handler func(*V, T) error, create func() T) *RegisteredMutation[V, T] {
+	// Derive the name and message type from a concrete instance produced by create().
+	// This avoids relying on reflect.TypeFor (which can yield unexpected results in some toolchains)
+	// and ensures we always peel off the pointer layer for proto messages.
+	instance := create()
+	rt := reflect.TypeOf(instance)
+	if rt.Kind() == reflect.Ptr {
+		rt = rt.Elem()
+	}
+	return &RegisteredMutation[V, T]{
+		name:    rt.Name(),
+		handler: handler,
+		create:  create,
+		msgType: rt,
+	}
+}
+
+func (m *RegisteredMutation[V, T]) Handle(state any, msg proto.Message) error {
+	return m.handler(state.(*V), msg.(T))
+}
+
+func (m *RegisteredMutation[V, T]) Name() string {
+	return m.name
+}
+
+func (m *RegisteredMutation[V, T]) Create() proto.Message {
+	return m.create()
+}
+
+func (m *RegisteredMutation[V, T]) Type() reflect.Type {
+	return m.msgType
+}
+
+func NewMutationRegistry() MutationRegistry {
+	return &ProtoMutationRegistry{
+		mutationRegistry:   make(map[reflect.Type]MutationHandler),
+		mutationRegistryMu: sync.RWMutex{},
+		processors:         make([]MutationProcessor, 0),
+	}
+}
+
+func (r *ProtoMutationRegistry) RegisterProcessor(processors ...MutationProcessor) {
+	r.processors = append(r.processors, processors...)
+}
+
+func (r *ProtoMutationRegistry) RegisterMutations(handlers ...MutationHandler) {
+	r.mutationRegistryMu.Lock()
+	defer r.mutationRegistryMu.Unlock()
+
+	for _, handler := range handlers {
+		r.mutationRegistry[handler.Type()] = handler
+	}
+}
+
+func (r *ProtoMutationRegistry) GetTypeName(msg proto.Message) (string, bool) {
+	r.mutationRegistryMu.RLock()
+	defer r.mutationRegistryMu.RUnlock()
+
+	rt := indirectType(reflect.TypeOf(msg))
+	if handler, ok := r.mutationRegistry[rt]; ok {
+		return handler.Name(), true
+	}
+	return "", false
+}
+
+func (r *ProtoMutationRegistry) getHandler(typeName string) MutationHandler {
+	r.mutationRegistryMu.Lock()
+	defer r.mutationRegistryMu.Unlock()
+
+	for _, handler := range r.mutationRegistry {
+		if handler.Name() == typeName {
+			return handler
+		}
+	}
+
+	return nil
+}
+
+func (r *ProtoMutationRegistry) Create(typeName string) (proto.Message, bool) {
+
+	handler := r.getHandler(typeName)
+	if handler == nil {
+		log.Printf("missing handler for %s", typeName)
+		return nil, false
+	}
+
+	return handler.Create(), true
+}
+
+// ApplyRegistered attempts to apply a registered mutation.
+// Returns updated grain if successful.
+//
+// If the mutation is not registered, returns (nil, ErrMutationNotRegistered).
+func (r *ProtoMutationRegistry) Apply(grain any, msg ...proto.Message) ([]ApplyResult, error) {
+	results := make([]ApplyResult, 0, len(msg))
+
+	if grain == nil {
+		return results, fmt.Errorf("nil grain")
+	}
+	// Nil slice of mutations still treated as an error (call contract violation).
+	if msg == nil {
+		return results, fmt.Errorf("nil mutation message")
+	}
+
+	for _, m := range msg {
+		// Ignore nil mutation elements (untyped or typed nil pointers) silently; they carry no data.
+		if m == nil {
+			continue
+		}
+		// Typed nil: interface holds concrete proto message type whose pointer value is nil.
+		rv := reflect.ValueOf(m)
+		if rv.Kind() == reflect.Ptr && rv.IsNil() {
+			continue
+		}
+		rt := indirectType(reflect.TypeOf(m))
+		r.mutationRegistryMu.RLock()
+		entry, ok := r.mutationRegistry[rt]
+		r.mutationRegistryMu.RUnlock()
+		if !ok {
+			results = append(results, ApplyResult{Error: ErrMutationNotRegistered, Type: rt.Name(), Mutation: m})
+			continue
+		}
+		err := entry.Handle(grain, m)
+		results = append(results, ApplyResult{Error: err, Type: rt.Name(), Mutation: m})
+	}
+
+	if len(results) > 0 {
+		for _, processor := range r.processors {
+			err := processor.Process(grain)
+			if err != nil {
+				return results, err
+			}
+		}
+	}
+	return results, nil
+}
+
+// RegisteredMutations returns metadata for all registered mutations (snapshot).
+func (r *ProtoMutationRegistry) RegisteredMutations() []string {
+	r.mutationRegistryMu.RLock()
+	defer r.mutationRegistryMu.RUnlock()
+	out := make([]string, 0, len(r.mutationRegistry))
+	for _, entry := range r.mutationRegistry {
+		out = append(out, entry.Name())
+	}
+	return out
+}
+
+// RegisteredMutationTypes returns the reflect.Type list of all registered messages.
+// Useful for coverage tests ensuring expected set matches actual set.
+func (r *ProtoMutationRegistry) RegisteredMutationTypes() []reflect.Type {
+	r.mutationRegistryMu.RLock()
+	defer r.mutationRegistryMu.RUnlock()
+	out := make([]reflect.Type, 0, len(r.mutationRegistry))
+	for _, entry := range r.mutationRegistry {
+		out = append(out, entry.Type())
+	}
+	return out
+}
+
+func indirectType(t reflect.Type) reflect.Type {
+	for t.Kind() == reflect.Ptr {
+		t = t.Elem()
+	}
+	return t
+}

pkg/actor/mutation_registry_test.go

@@ -0,0 +1,134 @@
+package actor
+
+import (
+	"errors"
+	"reflect"
+	"slices"
+	"testing"
+
+	"git.tornberg.me/go-cart-actor/pkg/messages"
+)
+
+type cartState struct {
+	calls     int
+	lastAdded *messages.AddItem
+}
+
+func TestRegisteredMutationBasics(t *testing.T) {
+	reg := NewMutationRegistry().(*ProtoMutationRegistry)
+
+	addItemMutation := NewMutation(
+		func(state *cartState, msg *messages.AddItem) error {
+			state.calls++
+			// copy to avoid external mutation side-effects (not strictly necessary for the test)
+			cp := msg
+			state.lastAdded = cp
+			return nil
+		},
+		func() *messages.AddItem { return &messages.AddItem{} },
+	)
+
+	// Sanity check on mutation metadata
+	if addItemMutation.Name() != "AddItem" {
+		t.Fatalf("expected mutation Name() == AddItem, got %s", addItemMutation.Name())
+	}
+	if got, want := addItemMutation.Type(), reflect.TypeOf(messages.AddItem{}); got != want {
+		t.Fatalf("expected Type() == %v, got %v", want, got)
+	}
+
+	reg.RegisterMutations(addItemMutation)
+
+	// RegisteredMutations: membership (order not guaranteed)
+	names := reg.RegisteredMutations()
+	if !slices.Contains(names, "AddItem") {
+		t.Fatalf("RegisteredMutations missing AddItem, got %v", names)
+	}
+
+	// RegisteredMutationTypes: membership (order not guaranteed)
+	types := reg.RegisteredMutationTypes()
+	if !slices.Contains(types, reflect.TypeOf(messages.AddItem{})) {
+		t.Fatalf("RegisteredMutationTypes missing AddItem type, got %v", types)
+	}
+
+	// GetTypeName should resolve for a pointer instance
+	name, ok := reg.GetTypeName(&messages.AddItem{})
+	if !ok || name != "AddItem" {
+		t.Fatalf("GetTypeName returned (%q,%v), expected (AddItem,true)", name, ok)
+	}
+
+	// GetTypeName should fail for unregistered type
+	if name, ok := reg.GetTypeName(&messages.Noop{}); ok || name != "" {
+		t.Fatalf("expected GetTypeName to fail for unregistered message, got (%q,%v)", name, ok)
+	}
+
+	// Create by name
+	msg, ok := reg.Create("AddItem")
+	if !ok {
+		t.Fatalf("Create failed for registered mutation")
+	}
+	if _, isAddItem := msg.(*messages.AddItem); !isAddItem {
+		t.Fatalf("Create returned wrong concrete type: %T", msg)
+	}
+
+	// Create unknown
+	if m2, ok := reg.Create("Unknown"); ok || m2 != nil {
+		t.Fatalf("Create should fail for unknown mutation, got (%T,%v)", m2, ok)
+	}
+
+	// Apply happy path
+	state := &cartState{}
+	add := &messages.AddItem{ItemId: 42, Quantity: 3, Sku: "ABC"}
+	if _, err := reg.Apply(state, add); err != nil {
+		t.Fatalf("Apply returned error: %v", err)
+	}
+	if state.calls != 1 {
+		t.Fatalf("handler not invoked expected calls=1 got=%d", state.calls)
+	}
+	if state.lastAdded == nil || state.lastAdded.ItemId != 42 || state.lastAdded.Quantity != 3 {
+		t.Fatalf("state not updated correctly: %+v", state.lastAdded)
+	}
+
+	// Apply nil grain
+	if _, err := reg.Apply(nil, add); err == nil {
+		t.Fatalf("expected error for nil grain")
+	}
+
+	// Apply nil message
+	if _, err := reg.Apply(state, nil); err == nil {
+		t.Fatalf("expected error for nil mutation message")
+	}
+
+	// Apply unregistered message
+	if _, err := reg.Apply(state, &messages.Noop{}); !errors.Is(err, ErrMutationNotRegistered) {
+		t.Fatalf("expected ErrMutationNotRegistered, got %v", err)
+	}
+}
+
+// func TestConcurrentSafeRegistrationLookup(t *testing.T) {
+// 	// This test is light-weight; it ensures locks don't deadlock under simple concurrent access.
+// 	reg := NewMutationRegistry().(*ProtoMutationRegistry)
+// 	mut := NewMutation[cartState, *messages.Noop](
+// 		func(state *cartState, msg *messages.Noop) error { state.calls++; return nil },
+// 		func() *messages.Noop { return &messages.Noop{} },
+// 	)
+// 	reg.RegisterMutations(mut)
+
+// 	done := make(chan struct{})
+// 	const workers = 25
+// 	for i := 0; i < workers; i++ {
+// 		go func() {
+// 			for j := 0; j < 100; j++ {
+// 				_, _ = reg.Create("Noop")
+// 				_, _ = reg.GetTypeName(&messages.Noop{})
+// 				_ = reg.Apply(&cartState{}, &messages.Noop{})
+// 			}
+// 			done <- struct{}{}
+// 		}()
+// 	}
+
+// 	for i := 0; i < workers; i++ {
+// 		<-done
+// 	}
+// }
+
+// Helpers

pkg/actor/simple_grain_pool.go

@@ -0,0 +1,454 @@
+package actor
+
+import (
+	"fmt"
+	"log"
+	"maps"
+	"sync"
+	"time"
+
+	"github.com/gogo/protobuf/proto"
+)
+
+type SimpleGrainPool[V any] struct {
+	// fields and methods
+	localMu          sync.RWMutex
+	grains           map[uint64]Grain[V]
+	mutationRegistry MutationRegistry
+	spawn            func(id uint64) (Grain[V], error)
+	spawnHost        func(host string) (Host, error)
+	listeners        []LogListener
+	storage          LogStorage[V]
+	ttl              time.Duration
+	poolSize         int
+
+	// Cluster coordination --------------------------------------------------
+	hostname     string
+	remoteMu     sync.RWMutex
+	remoteOwners map[uint64]Host
+	remoteHosts  map[string]Host
+	//discardedHostHandler *DiscardedHostHandler
+
+	// House-keeping ---------------------------------------------------------
+	purgeTicker *time.Ticker
+}
+
+type GrainPoolConfig[V any] struct {
+	Hostname         string
+	Spawn            func(id uint64) (Grain[V], error)
+	SpawnHost        func(host string) (Host, error)
+	TTL              time.Duration
+	PoolSize         int
+	MutationRegistry MutationRegistry
+	Storage          LogStorage[V]
+}
+
+func NewSimpleGrainPool[V any](config GrainPoolConfig[V]) (*SimpleGrainPool[V], error) {
+	p := &SimpleGrainPool[V]{
+		grains:           make(map[uint64]Grain[V]),
+		mutationRegistry: config.MutationRegistry,
+		storage:          config.Storage,
+		spawn:            config.Spawn,
+		spawnHost:        config.SpawnHost,
+		ttl:              config.TTL,
+		poolSize:         config.PoolSize,
+		hostname:         config.Hostname,
+		remoteOwners:     make(map[uint64]Host),
+		remoteHosts:      make(map[string]Host),
+	}
+
+	p.purgeTicker = time.NewTicker(time.Minute)
+	go func() {
+		for range p.purgeTicker.C {
+			p.purge()
+		}
+	}()
+
+	return p, nil
+}
+
+func (p *SimpleGrainPool[V]) AddListener(listener LogListener) {
+	p.listeners = append(p.listeners, listener)
+}
+
+func (p *SimpleGrainPool[V]) RemoveListener(listener LogListener) {
+	for i, l := range p.listeners {
+		if l == listener {
+			p.listeners = append(p.listeners[:i], p.listeners[i+1:]...)
+			break
+		}
+	}
+}
+
+func (p *SimpleGrainPool[V]) purge() {
+	purgeLimit := time.Now().Add(-p.ttl)
+	purgedIds := make([]uint64, 0, len(p.grains))
+	p.localMu.Lock()
+	for id, grain := range p.grains {
+		if grain.GetLastAccess().Before(purgeLimit) {
+			purgedIds = append(purgedIds, id)
+
+			delete(p.grains, id)
+		}
+	}
+	p.localMu.Unlock()
+	p.forAllHosts(func(remote Host) {
+		remote.AnnounceExpiry(purgedIds)
+	})
+
+}
+
+// LocalUsage returns the number of resident grains and configured capacity.
+func (p *SimpleGrainPool[V]) LocalUsage() (int, int) {
+	p.localMu.RLock()
+	defer p.localMu.RUnlock()
+	return len(p.grains), p.poolSize
+}
+
+// LocalCartIDs returns the currently owned cart ids (for control-plane RPCs).
+func (p *SimpleGrainPool[V]) GetLocalIds() []uint64 {
+	p.localMu.RLock()
+	defer p.localMu.RUnlock()
+	ids := make([]uint64, 0, len(p.grains))
+	for _, g := range p.grains {
+		if g == nil {
+			continue
+		}
+		ids = append(ids, uint64(g.GetId()))
+	}
+	return ids
+}
+
+func (p *SimpleGrainPool[V]) HandleRemoteExpiry(host string, ids []uint64) error {
+	p.remoteMu.Lock()
+	defer p.remoteMu.Unlock()
+	for _, id := range ids {
+		delete(p.remoteOwners, id)
+	}
+	return nil
+}
+
+func (p *SimpleGrainPool[V]) HandleOwnershipChange(host string, ids []uint64) error {
+	log.Printf("host %s now owns %d cart ids", host, len(ids))
+	p.remoteMu.RLock()
+	remoteHost, exists := p.remoteHosts[host]
+	p.remoteMu.RUnlock()
+	if !exists {
+		createdHost, err := p.AddRemote(host)
+		if err != nil {
+			return err
+		}
+		remoteHost = createdHost
+	}
+	p.remoteMu.Lock()
+	defer p.remoteMu.Unlock()
+	p.localMu.Lock()
+	defer p.localMu.Unlock()
+	for _, id := range ids {
+		log.Printf("Handling ownership change for cart %d to host %s", id, host)
+		delete(p.grains, id)
+		p.remoteOwners[id] = remoteHost
+	}
+	return nil
+}
+
+// TakeOwnership takes ownership of a grain.
+func (p *SimpleGrainPool[V]) TakeOwnership(id uint64) {
+	p.broadcastOwnership([]uint64{id})
+}
+
+func (p *SimpleGrainPool[V]) AddRemoteHost(host string) {
+	p.AddRemote(host)
+}
+
+func (p *SimpleGrainPool[V]) AddRemote(host string) (Host, error) {
+	if host == "" {
+		return nil, fmt.Errorf("host is empty")
+	}
+	if host == p.hostname {
+		return nil, fmt.Errorf("same host, this should not happen")
+	}
+	p.remoteMu.RLock()
+	existing, found := p.remoteHosts[host]
+	p.remoteMu.RUnlock()
+	if found {
+		return existing, nil
+	}
+
+	remote, err := p.spawnHost(host)
+	if err != nil {
+		log.Printf("AddRemote %s failed: %v", host, err)
+
+		return nil, err
+	}
+	p.remoteMu.Lock()
+	p.remoteHosts[host] = remote
+	p.remoteMu.Unlock()
+	// connectedRemotes.Set(float64(p.RemoteCount()))
+
+	log.Printf("Connected to remote host %s", host)
+	go p.pingLoop(remote)
+	go p.initializeRemote(remote)
+	go p.SendNegotiation()
+	return remote, nil
+}
+
+func (p *SimpleGrainPool[V]) initializeRemote(remote Host) {
+
+	remotesIds := remote.GetActorIds()
+
+	p.remoteMu.Lock()
+	for _, id := range remotesIds {
+		p.localMu.Lock()
+		delete(p.grains, id)
+		p.localMu.Unlock()
+		if _, exists := p.remoteOwners[id]; !exists {
+			p.remoteOwners[id] = remote
+		}
+	}
+	p.remoteMu.Unlock()
+
+}
+
+func (p *SimpleGrainPool[V]) RemoveHost(host string) {
+	p.remoteMu.Lock()
+	remote, exists := p.remoteHosts[host]
+
+	if exists {
+		go remote.Close()
+		delete(p.remoteHosts, host)
+	}
+	count := 0
+	for id, owner := range p.remoteOwners {
+		if owner.Name() == host {
+			count++
+			delete(p.remoteOwners, id)
+		}
+	}
+	log.Printf("Removing host %s, grains: %d", host, count)
+	p.remoteMu.Unlock()
+
+	if exists {
+		remote.Close()
+	}
+	// connectedRemotes.Set(float64(p.RemoteCount()))
+}
+
+func (p *SimpleGrainPool[V]) RemoteCount() int {
+	p.remoteMu.RLock()
+	defer p.remoteMu.RUnlock()
+	return len(p.remoteHosts)
+}
+
+// RemoteHostNames returns a snapshot of connected remote host identifiers.
+func (p *SimpleGrainPool[V]) RemoteHostNames() []string {
+	p.remoteMu.RLock()
+	defer p.remoteMu.RUnlock()
+	hosts := make([]string, 0, len(p.remoteHosts))
+	for host := range p.remoteHosts {
+		hosts = append(hosts, host)
+	}
+	return hosts
+}
+
+func (p *SimpleGrainPool[V]) IsKnown(host string) bool {
+	if host == p.hostname {
+		return true
+	}
+	p.remoteMu.RLock()
+	defer p.remoteMu.RUnlock()
+	_, ok := p.remoteHosts[host]
+	return ok
+}
+
+func (p *SimpleGrainPool[V]) pingLoop(remote Host) {
+	remote.Ping()
+	ticker := time.NewTicker(5 * time.Second)
+	defer ticker.Stop()
+	for range ticker.C {
+		if !remote.Ping() {
+			if !remote.IsHealthy() {
+				log.Printf("Remote %s unhealthy, removing", remote.Name())
+				p.Close()
+				p.RemoveHost(remote.Name())
+				return
+			}
+			continue
+		}
+	}
+}
+
+func (p *SimpleGrainPool[V]) IsHealthy() bool {
+	p.remoteMu.RLock()
+	defer p.remoteMu.RUnlock()
+	for _, r := range p.remoteHosts {
+		if !r.IsHealthy() {
+			return false
+		}
+	}
+	return true
+}
+
+func (p *SimpleGrainPool[V]) Negotiate(otherHosts []string) {
+
+	for _, host := range otherHosts {
+		if host != p.hostname {
+			p.remoteMu.RLock()
+			_, ok := p.remoteHosts[host]
+			p.remoteMu.RUnlock()
+			if !ok {
+				go p.AddRemote(host)
+			}
+		}
+	}
+}
+
+func (p *SimpleGrainPool[V]) SendNegotiation() {
+	//negotiationCount.Inc()
+
+	p.remoteMu.RLock()
+	hosts := make([]string, 0, len(p.remoteHosts)+1)
+	hosts = append(hosts, p.hostname)
+	remotes := make([]Host, 0, len(p.remoteHosts))
+	for h, r := range p.remoteHosts {
+		hosts = append(hosts, h)
+		remotes = append(remotes, r)
+	}
+	p.remoteMu.RUnlock()
+
+	p.forAllHosts(func(remote Host) {
+		knownByRemote, err := remote.Negotiate(hosts)
+
+		if err != nil {
+			log.Printf("Negotiate with %s failed: %v", remote.Name(), err)
+			return
+		}
+		for _, h := range knownByRemote {
+			if !p.IsKnown(h) {
+				go p.AddRemote(h)
+			}
+		}
+	})
+}
+
+func (p *SimpleGrainPool[V]) forAllHosts(fn func(Host)) {
+	p.remoteMu.RLock()
+	rh := maps.Clone(p.remoteHosts)
+	p.remoteMu.RUnlock()
+
+	wg := sync.WaitGroup{}
+	for _, host := range rh {
+
+		wg.Go(func() { fn(host) })
+
+	}
+
+	for name, host := range rh {
+		if !host.IsHealthy() {
+			host.Close()
+			p.remoteMu.Lock()
+			delete(p.remoteHosts, name)
+			p.remoteMu.Unlock()
+		}
+
+	}
+}
+
+func (p *SimpleGrainPool[V]) broadcastOwnership(ids []uint64) {
+	if len(ids) == 0 {
+		return
+	}
+
+	p.forAllHosts(func(rh Host) {
+		rh.AnnounceOwnership(p.hostname, ids)
+	})
+	log.Printf("%s taking ownership of %d ids", p.hostname, len(ids))
+	// go p.statsUpdate()
+}
+
+func (p *SimpleGrainPool[V]) getOrClaimGrain(id uint64) (Grain[V], error) {
+	p.localMu.RLock()
+	grain, exists := p.grains[id]
+	p.localMu.RUnlock()
+	if exists && grain != nil {
+		return grain, nil
+	}
+
+	grain, err := p.spawn(id)
+	if err != nil {
+		return nil, err
+	}
+	p.localMu.Lock()
+	p.grains[id] = grain
+	p.localMu.Unlock()
+	go p.broadcastOwnership([]uint64{id})
+	return grain, nil
+}
+
+// // ErrNotOwner is returned when a cart belongs to another host.
+// var ErrNotOwner = fmt.Errorf("not owner")
+
+// Apply applies a mutation to a grain.
+func (p *SimpleGrainPool[V]) Apply(id uint64, mutation ...proto.Message) (*MutationResult[*V], error) {
+	grain, err := p.getOrClaimGrain(id)
+	if err != nil {
+		return nil, err
+	}
+
+	mutations, err := p.mutationRegistry.Apply(grain, mutation...)
+	if err != nil {
+		return nil, err
+	}
+	if p.storage != nil {
+		go func() {
+			if err := p.storage.AppendMutations(id, mutation...); err != nil {
+				log.Printf("failed to store mutation for grain %d: %v", id, err)
+			}
+		}()
+	}
+	for _, listener := range p.listeners {
+		go listener.AppendMutations(id, mutations...)
+	}
+	result, err := grain.GetCurrentState()
+	if err != nil {
+		return nil, err
+	}
+	return &MutationResult[*V]{
+		Result:    result,
+		Mutations: mutations,
+	}, nil
+}
+
+// Get returns the current state of a grain.
+func (p *SimpleGrainPool[V]) Get(id uint64) (*V, error) {
+	grain, err := p.getOrClaimGrain(id)
+	if err != nil {
+		return nil, err
+	}
+	return grain.GetCurrentState()
+}
+
+// OwnerHost reports the remote owner (if any) for the supplied cart id.
+func (p *SimpleGrainPool[V]) OwnerHost(id uint64) (Host, bool) {
+	p.remoteMu.RLock()
+	defer p.remoteMu.RUnlock()
+	owner, ok := p.remoteOwners[id]
+	return owner, ok
+}
+
+// Hostname returns the local hostname (pod IP).
+func (p *SimpleGrainPool[V]) Hostname() string {
+	return p.hostname
+}
+
+// Close notifies remotes that this host is shutting down.
+func (p *SimpleGrainPool[V]) Close() {
+
+	p.forAllHosts(func(rh Host) {
+		rh.Close()
+	})
+
+	if p.purgeTicker != nil {
+		p.purgeTicker.Stop()
+	}
+}

pkg/actor/state.go

@@ -0,0 +1,98 @@
+package actor
+
+import (
+	"bufio"
+	"encoding/json"
+	"errors"
+	"io"
+	"time"
+
+	"github.com/gogo/protobuf/proto"
+)
+
+type StateStorage struct {
+	registry MutationRegistry
+}
+
+type StorageEvent struct {
+	Type      string        `json:"type"`
+	TimeStamp time.Time     `json:"timestamp"`
+	Mutation  proto.Message `json:"mutation"`
+}
+
+type rawEvent struct {
+	Type      string          `json:"type"`
+	TimeStamp time.Time       `json:"timestamp"`
+	Mutation  json.RawMessage `json:"mutation"`
+}
+
+func NewState(registry MutationRegistry) *StateStorage {
+	return &StateStorage{
+		registry: registry,
+	}
+}
+
+var ErrUnknownType = errors.New("unknown type")
+
+func (s *StateStorage) Load(r io.Reader, onMessage func(msg proto.Message)) error {
+	var err error
+	var evt *StorageEvent
+	scanner := bufio.NewScanner(r)
+	for err == nil {
+		evt, err = s.Read(scanner)
+		if err == nil {
+			onMessage(evt.Mutation)
+		}
+	}
+	if err == io.EOF {
+		return nil
+	}
+	return err
+}
+
+func (s *StateStorage) Append(io io.Writer, mutation proto.Message, timeStamp time.Time) error {
+	typeName, ok := s.registry.GetTypeName(mutation)
+	if !ok {
+		return ErrUnknownType
+	}
+	event := &StorageEvent{
+		Type:      typeName,
+		TimeStamp: timeStamp,
+		Mutation:  mutation,
+	}
+	jsonBytes, err := json.Marshal(event)
+	if err != nil {
+		return err
+	}
+	if _, err := io.Write(jsonBytes); err != nil {
+		return err
+	}
+	io.Write([]byte("\n"))
+	return nil
+}
+
+func (s *StateStorage) Read(r *bufio.Scanner) (*StorageEvent, error) {
+	var event rawEvent
+
+	if r.Scan() {
+		b := r.Bytes()
+		err := json.Unmarshal(b, &event)
+		if err != nil {
+			return nil, err
+		}
+		typeName := event.Type
+		mutation, ok := s.registry.Create(typeName)
+		if !ok {
+			return nil, ErrUnknownType
+		}
+		if err := json.Unmarshal(event.Mutation, mutation); err != nil {
+			return nil, err
+		}
+		return &StorageEvent{
+			Type:      typeName,
+			TimeStamp: event.TimeStamp,
+			Mutation:  mutation,
+		}, r.Err()
+	}
+	return nil, io.EOF
+}

pkg/cart/cart-grain.go

@@ -0,0 +1,288 @@
+package cart
+
+import (
+	"encoding/json"
+	"slices"
+	"sync"
+	"time"
+
+	messages "git.tornberg.me/go-cart-actor/pkg/messages"
+	"git.tornberg.me/go-cart-actor/pkg/voucher"
+)
+
+// Legacy padded [16]byte CartId and its helper methods removed.
+// Unified CartId (uint64 with base62 string form) now defined in cart_id.go.
+
+type StockStatus int
+
+type ItemMeta struct {
+	Name       string  `json:"name"`
+	Brand      string  `json:"brand,omitempty"`
+	Category   string  `json:"category,omitempty"`
+	Category2  string  `json:"category2,omitempty"`
+	Category3  string  `json:"category3,omitempty"`
+	Category4  string  `json:"category4,omitempty"`
+	Category5  string  `json:"category5,omitempty"`
+	SellerId   string  `json:"sellerId,omitempty"`
+	SellerName string  `json:"sellerName,omitempty"`
+	Image      string  `json:"image,omitempty"`
+	Outlet     *string `json:"outlet,omitempty"`
+}
+
+type CartItem struct {
+	Id          uint32      `json:"id"`
+	ItemId      uint32      `json:"itemId,omitempty"`
+	ParentId    *uint32     `json:"parentId,omitempty"`
+	Sku         string      `json:"sku"`
+	Price       Price       `json:"price"`
+	TotalPrice  Price       `json:"totalPrice"`
+	OrgPrice    *Price      `json:"orgPrice,omitempty"`
+	Stock       StockStatus `json:"stock"`
+	Quantity    int         `json:"qty"`
+	Discount    *Price      `json:"discount,omitempty"`
+	Disclaimer  string      `json:"disclaimer,omitempty"`
+	ArticleType string      `json:"type,omitempty"`
+	StoreId     *string     `json:"storeId,omitempty"`
+	Meta        *ItemMeta   `json:"meta,omitempty"`
+	SaleStatus  string      `json:"saleStatus"`
+}
+
+type CartDelivery struct {
+	Id          uint32                `json:"id"`
+	Provider    string                `json:"provider"`
+	Price       Price                 `json:"price"`
+	Items       []uint32              `json:"items"`
+	PickupPoint *messages.PickupPoint `json:"pickupPoint,omitempty"`
+}
+
+type CartNotification struct {
+	LinkedId int    `json:"id"`
+	Provider string `json:"provider"`
+	Title    string `json:"title"`
+	Content  string `json:"content"`
+}
+
+type SubscriptionDetails struct {
+	Id           string          `json:"id"`
+	OfferingCode string          `json:"offeringCode,omitempty"`
+	SigningType  string          `json:"signingType,omitempty"`
+	Meta         json.RawMessage `json:"data,omitempty"`
+}
+
+type CartGrain struct {
+	mu                  sync.RWMutex
+	lastItemId          uint32
+	lastDeliveryId      uint32
+	lastVoucherId       uint32
+	lastAccess          time.Time
+	lastChange          time.Time // unix seconds of last successful mutation (replay sets from event ts)
+	userId              string
+	Id                  CartId                          `json:"id"`
+	Items               []*CartItem                     `json:"items"`
+	TotalPrice          *Price                          `json:"totalPrice"`
+	TotalDiscount       *Price                          `json:"totalDiscount"`
+	Deliveries          []*CartDelivery                 `json:"deliveries,omitempty"`
+	Processing          bool                            `json:"processing"`
+	PaymentInProgress   bool                            `json:"paymentInProgress"`
+	OrderReference      string                          `json:"orderReference,omitempty"`
+	PaymentStatus       string                          `json:"paymentStatus,omitempty"`
+	Vouchers            []*Voucher                      `json:"vouchers,omitempty"`
+	Notifications       []CartNotification              `json:"cartNotification,omitempty"`
+	SubscriptionDetails map[string]*SubscriptionDetails `json:"subscriptionDetails,omitempty"`
+}
+
+type Voucher struct {
+	Code        string   `json:"code"`
+	Applied     bool     `json:"applied"`
+	Rules       []string `json:"rules"`
+	Description string   `json:"description,omitempty"`
+	Id          uint32   `json:"id"`
+	Value       int64    `json:"value"`
+}
+
+func (v *Voucher) AppliesTo(cart *CartGrain) ([]*CartItem, bool) {
+	// No rules -> applies to entire cart
+	if len(v.Rules) == 0 {
+		return cart.Items, true
+	}
+
+	// Build evaluation context once
+	ctx := voucher.EvalContext{
+		Items:        make([]voucher.Item, 0, len(cart.Items)),
+		CartTotalInc: 0,
+	}
+
+	if cart.TotalPrice != nil {
+		ctx.CartTotalInc = cart.TotalPrice.IncVat
+	}
+
+	for _, it := range cart.Items {
+		category := ""
+		if it.Meta != nil {
+			category = it.Meta.Category
+		}
+		ctx.Items = append(ctx.Items, voucher.Item{
+			Sku:       it.Sku,
+			Category:  category,
+			UnitPrice: it.Price.IncVat,
+		})
+	}
+
+	// All voucher rules must pass (logical AND)
+	for _, expr := range v.Rules {
+
+		if expr == "" {
+			// Empty condition treated as pass (acts like a comment / placeholder)
+			continue
+		}
+		rs, err := voucher.ParseRules(expr)
+		if err != nil {
+			// Fail closed on parse error
+			return nil, false
+		}
+		if !rs.Applies(ctx) {
+			return nil, false
+		}
+	}
+
+	return cart.Items, true
+}
+
+func NewCartGrain(id uint64, ts time.Time) *CartGrain {
+	return &CartGrain{
+		lastItemId:          0,
+		lastDeliveryId:      0,
+		lastVoucherId:       0,
+		lastAccess:          ts,
+		lastChange:          ts,
+		TotalDiscount:       NewPrice(),
+		Vouchers:            []*Voucher{},
+		Deliveries:          []*CartDelivery{},
+		Id:                  CartId(id),
+		Items:               []*CartItem{},
+		TotalPrice:          NewPrice(),
+		SubscriptionDetails: make(map[string]*SubscriptionDetails),
+	}
+}
+
+func (c *CartGrain) GetId() uint64 {
+	return uint64(c.Id)
+}
+
+func (c *CartGrain) GetLastChange() time.Time {
+	return c.lastChange
+}
+
+func (c *CartGrain) GetLastAccess() time.Time {
+	return c.lastAccess
+}
+
+func (c *CartGrain) GetCurrentState() (*CartGrain, error) {
+	c.lastAccess = time.Now()
+	return c, nil
+}
+
+func (c *CartGrain) GetState() ([]byte, error) {
+	return json.Marshal(c)
+}
+
+func (c *CartGrain) ItemsWithDelivery() []uint32 {
+	ret := make([]uint32, 0, len(c.Items))
+	for _, item := range c.Items {
+		for _, delivery := range c.Deliveries {
+			for _, id := range delivery.Items {
+				if item.Id == id {
+					ret = append(ret, id)
+				}
+			}
+		}
+	}
+	return ret
+}
+
+func (c *CartGrain) ItemsWithoutDelivery() []uint32 {
+	ret := make([]uint32, 0, len(c.Items))
+	hasDelivery := c.ItemsWithDelivery()
+	for _, item := range c.Items {
+		found := slices.Contains(hasDelivery, item.Id)
+
+		if !found {
+			ret = append(ret, item.Id)
+		}
+	}
+	return ret
+}
+
+func (c *CartGrain) FindItemWithSku(sku string) (*CartItem, bool) {
+	c.mu.RLock()
+	defer c.mu.RUnlock()
+	for _, item := range c.Items {
+		if item.Sku == sku {
+			return item, true
+		}
+	}
+	return nil, false
+}
+
+// func (c *CartGrain) Apply(content proto.Message, isReplay bool) (*CartGrain, error) {
+
+// 	updated, err := ApplyRegistered(c, content)
+// 	if err != nil {
+// 		if err == ErrMutationNotRegistered {
+// 			return nil, fmt.Errorf("unsupported mutation type %T (not registered)", content)
+// 		}
+// 		return nil, err
+// 	}
+
+// 	// Sliding TTL: update lastChange only for non-replay successful mutations.
+// 	if updated != nil && !isReplay {
+// 		c.lastChange = time.Now()
+// 		c.lastAccess = time.Now()
+// 		go AppendCartEvent(c.Id, content)
+// 	}
+
+// 	return updated, nil
+// }
+
+func (c *CartGrain) UpdateTotals() {
+	c.TotalPrice = NewPrice()
+	c.TotalDiscount = NewPrice()
+
+	for _, item := range c.Items {
+		rowTotal := MultiplyPrice(item.Price, int64(item.Quantity))
+
+		if item.OrgPrice != nil {
+			diff := NewPrice()
+			diff.Add(*item.OrgPrice)
+			diff.Subtract(item.Price)
+			diff.Multiply(int64(item.Quantity))
+			rowTotal.Subtract(*diff)
+			item.Discount = diff
+			if diff.IncVat > 0 {
+				c.TotalDiscount.Add(*diff)
+			}
+		}
+
+		item.TotalPrice = *rowTotal
+
+		c.TotalPrice.Add(*rowTotal)
+
+	}
+	for _, delivery := range c.Deliveries {
+		c.TotalPrice.Add(delivery.Price)
+	}
+	for _, voucher := range c.Vouchers {
+		_, ok := voucher.AppliesTo(c)
+		voucher.Applied = false
+		if ok {
+			value := NewPriceFromIncVat(voucher.Value, 25)
+			if c.TotalPrice.IncVat <= value.IncVat {
+				// don't apply discounts to more than the total price
+				continue
+			}
+			voucher.Applied = true
+			c.TotalDiscount.Add(*value)
+			c.TotalPrice.Subtract(*value)
+		}
+	}
+}

pkg/cart/cart-mutation-helper.go

@@ -0,0 +1,54 @@
+package cart
+
+import (
+	"git.tornberg.me/go-cart-actor/pkg/actor"
+	messages "git.tornberg.me/go-cart-actor/pkg/messages"
+)
+
+func NewCartMultationRegistry() actor.MutationRegistry {
+
+	reg := actor.NewMutationRegistry()
+	reg.RegisterMutations(
+		actor.NewMutation(AddItem, func() *messages.AddItem {
+			return &messages.AddItem{}
+		}),
+		actor.NewMutation(ChangeQuantity, func() *messages.ChangeQuantity {
+			return &messages.ChangeQuantity{}
+		}),
+		actor.NewMutation(RemoveItem, func() *messages.RemoveItem {
+			return &messages.RemoveItem{}
+		}),
+		actor.NewMutation(InitializeCheckout, func() *messages.InitializeCheckout {
+			return &messages.InitializeCheckout{}
+		}),
+		actor.NewMutation(OrderCreated, func() *messages.OrderCreated {
+			return &messages.OrderCreated{}
+		}),
+		actor.NewMutation(RemoveDelivery, func() *messages.RemoveDelivery {
+			return &messages.RemoveDelivery{}
+		}),
+		actor.NewMutation(SetDelivery, func() *messages.SetDelivery {
+			return &messages.SetDelivery{}
+		}),
+		actor.NewMutation(SetPickupPoint, func() *messages.SetPickupPoint {
+			return &messages.SetPickupPoint{}
+		}),
+		actor.NewMutation(ClearCart, func() *messages.ClearCartRequest {
+			return &messages.ClearCartRequest{}
+		}),
+		actor.NewMutation(AddVoucher, func() *messages.AddVoucher {
+			return &messages.AddVoucher{}
+		}),
+		actor.NewMutation(RemoveVoucher, func() *messages.RemoveVoucher {
+			return &messages.RemoveVoucher{}
+		}),
+		actor.NewMutation(UpsertSubscriptionDetails, func() *messages.UpsertSubscriptionDetails {
+			return &messages.UpsertSubscriptionDetails{}
+		}),
+		actor.NewMutation(PreConditionFailed, func() *messages.PreConditionFailed {
+			return &messages.PreConditionFailed{}
+		}),
+	)
+	return reg
+
+}

pkg/cart/cart_grain_totals_test.go

@@ -0,0 +1,48 @@
+package cart
+
+import (
+	"testing"
+)
+
+// helper to create a cart grain with items and deliveries
+func newTestCart() *CartGrain {
+	return &CartGrain{Items: []*CartItem{}, Deliveries: []*CartDelivery{}, Vouchers: []*Voucher{}, Notifications: []CartNotification{}}
+}
+
+func TestCartGrainUpdateTotalsBasic(t *testing.T) {
+	c := newTestCart()
+	// Item1 price 1250 (ex 1000 vat 250) org price higher -> discount 200 per unit
+	item1Price := Price{IncVat: 1250, VatRates: map[float32]int64{25: 250}}
+	item1Org := &Price{IncVat: 1500, VatRates: map[float32]int64{25: 300}}
+	item2Price := Price{IncVat: 2000, VatRates: map[float32]int64{25: 400}}
+	c.Items = []*CartItem{
+		{Id: 1, Price: item1Price, OrgPrice: item1Org, Quantity: 2},
+		{Id: 2, Price: item2Price, OrgPrice: &item2Price, Quantity: 1},
+	}
+	deliveryPrice := Price{IncVat: 4900, VatRates: map[float32]int64{25: 980}}
+	c.Deliveries = []*CartDelivery{{Id: 1, Price: deliveryPrice, Items: []uint32{1, 2}}}
+
+	c.UpdateTotals()
+
+	// Expected totals: sum inc vat of items * qty plus delivery
+	// item1 total inc = 1250*2 = 2500
+	// item2 total inc = 2000*1 = 2000
+	// delivery inc = 4900
+	expectedInc := int64(2500 + 2000 + 4900)
+	if c.TotalPrice.IncVat != expectedInc {
+		t.Fatalf("TotalPrice IncVat expected %d got %d", expectedInc, c.TotalPrice.IncVat)
+	}
+
+	// Discount: current implementation computes (OrgPrice - Price) ignoring quantity -> 1500-1250=250
+	if c.TotalDiscount.IncVat != 250 {
+		t.Fatalf("TotalDiscount expected 250 got %d", c.TotalDiscount.IncVat)
+	}
+}
+
+func TestCartGrainUpdateTotalsNoItems(t *testing.T) {
+	c := newTestCart()
+	c.UpdateTotals()
+	if c.TotalPrice.IncVat != 0 || c.TotalDiscount.IncVat != 0 {
+		t.Fatalf("expected zero totals got %+v", c)
+	}
+}

pkg/cart/cart_id.go

@@ -0,0 +1,159 @@
+package cart
+
+import (
+	"crypto/rand"
+	"encoding/json"
+	"fmt"
+)
+
+// cart_id.go
+//
+// Breaking change:
+//   Unified cart identifier as a raw 64-bit unsigned integer (type CartId uint64).
+//   External textual representation: base62 (0-9 A-Z a-z), shortest possible
+//   encoding for 64 bits (max 11 characters, since 62^11 > 2^64).
+//
+// Rationale:
+//   - Replaces legacy fixed [16]byte padded string and transitional CartID wrapper.
+//   - Provides compact, URL/cookie-friendly identifiers.
+//   - O(1) hashing and minimal memory footprint.
+//   - 64 bits of crypto randomness => negligible collision probability at realistic scale.
+//
+// Public API:
+//   type CartId uint64
+//   func NewCartId() (CartId, error)
+//   func MustNewCartId() CartId
+//   func ParseCartId(string) (CartId, bool)
+//   func MustParseCartId(string) CartId
+//   (CartId).String() string
+//   (CartId).MarshalJSON() / UnmarshalJSON()
+//
+// NOTE:
+//   All legacy helpers (UpgradeLegacyCartId, Fallback hashing, Canonicalize variants,
+//   CartIDToLegacy, LegacyToCartID) have been removed as part of the breaking change.
+//
+// ---------------------------------------------------------------------------
+
+type CartId uint64
+
+const base62Alphabet = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"
+
+// Reverse lookup (0xFF marks invalid)
+var base62Rev [256]byte
+
+func init() {
+	for i := range base62Rev {
+		base62Rev[i] = 0xFF
+	}
+	for i := 0; i < len(base62Alphabet); i++ {
+		base62Rev[base62Alphabet[i]] = byte(i)
+	}
+}
+
+// String returns the canonical base62 encoding of the 64-bit id.
+func (id CartId) String() string {
+	return encodeBase62(uint64(id))
+}
+
+// MarshalJSON encodes the cart id as a JSON string.
+func (id CartId) MarshalJSON() ([]byte, error) {
+	return json.Marshal(id.String())
+}
+
+// UnmarshalJSON decodes a cart id from a JSON string containing base62 text.
+func (id *CartId) UnmarshalJSON(data []byte) error {
+	var s string
+	if err := json.Unmarshal(data, &s); err != nil {
+		return err
+	}
+	parsed, ok := ParseCartId(s)
+	if !ok {
+		return fmt.Errorf("invalid cart id: %q", s)
+	}
+	*id = parsed
+	return nil
+}
+
+// NewCartId generates a new cryptographically random non-zero 64-bit id.
+func NewCartId() (CartId, error) {
+	var b [8]byte
+	if _, err := rand.Read(b[:]); err != nil {
+		return 0, fmt.Errorf("NewCartId: %w", err)
+	}
+	u := (uint64(b[0]) << 56) |
+		(uint64(b[1]) << 48) |
+		(uint64(b[2]) << 40) |
+		(uint64(b[3]) << 32) |
+		(uint64(b[4]) << 24) |
+		(uint64(b[5]) << 16) |
+		(uint64(b[6]) << 8) |
+		uint64(b[7])
+	if u == 0 {
+		// Extremely unlikely; regenerate once to avoid "0" identifier if desired.
+		return NewCartId()
+	}
+	return CartId(u), nil
+}
+
+// MustNewCartId panics if generation fails.
+func MustNewCartId() CartId {
+	id, err := NewCartId()
+	if err != nil {
+		panic(err)
+	}
+	return id
+}
+
+// ParseCartId parses a base62 string into a CartId.
+// Returns (0,false) for invalid input.
+func ParseCartId(s string) (CartId, bool) {
+	// Accept length 1..11 (11 sufficient for 64 bits). Reject >11 immediately.
+	// Provide a slightly looser upper bound (<=16) only if you anticipate future
+	// extensions; here we stay strict.
+	if len(s) == 0 || len(s) > 11 {
+		return 0, false
+	}
+	u, ok := decodeBase62(s)
+	if !ok {
+		return 0, false
+	}
+	return CartId(u), true
+}
+
+// MustParseCartId panics on invalid base62 input.
+func MustParseCartId(s string) CartId {
+	id, ok := ParseCartId(s)
+	if !ok {
+		panic(fmt.Sprintf("invalid cart id: %q", s))
+	}
+	return id
+}
+
+// encodeBase62 converts a uint64 to base62 (shortest form).
+func encodeBase62(u uint64) string {
+	if u == 0 {
+		return "0"
+	}
+	var buf [11]byte
+	i := len(buf)
+	for u > 0 {
+		i--
+		buf[i] = base62Alphabet[u%62]
+		u /= 62
+	}
+	return string(buf[i:])
+}
+
+// decodeBase62 converts base62 text to uint64.
+func decodeBase62(s string) (uint64, bool) {
+	var v uint64
+	for i := 0; i < len(s); i++ {
+		c := s[i]
+		d := base62Rev[c]
+		if d == 0xFF {
+			return 0, false
+		}
+		v = v*62 + uint64(d)
+	}
+	return v, true
+}

pkg/cart/cart_id_test.go

@@ -0,0 +1,185 @@
+package cart
+
+import (
+	"encoding/json"
+	"fmt"
+	"testing"
+)
+
+// TestNewCartIdUniqueness generates many ids and checks for collisions.
+func TestNewCartIdUniqueness(t *testing.T) {
+	const n = 20000
+	seen := make(map[string]struct{}, n)
+	for i := 0; i < n; i++ {
+		id, err := NewCartId()
+		if err != nil {
+			t.Fatalf("NewCartId error: %v", err)
+		}
+		s := id.String()
+		if _, exists := seen[s]; exists {
+			t.Fatalf("duplicate id encountered: %s", s)
+		}
+		seen[s] = struct{}{}
+		if s == "" {
+			t.Fatalf("empty string representation for id %d", id)
+		}
+		if len(s) > 11 {
+			t.Fatalf("encoded id length exceeds 11 chars: %s (%d)", s, len(s))
+		}
+		if id == 0 {
+			// We force regeneration on zero, extremely unlikely but test guards intent.
+			t.Fatalf("zero id generated (should be regenerated)")
+		}
+	}
+}
+
+// TestParseCartIdRoundTrip ensures parse -> string -> parse is stable.
+func TestParseCartIdRoundTrip(t *testing.T) {
+	id := MustNewCartId()
+	txt := id.String()
+	parsed, ok := ParseCartId(txt)
+	if !ok {
+		t.Fatalf("ParseCartId failed for valid text %q", txt)
+	}
+	if parsed != id {
+		t.Fatalf("round trip mismatch: original=%d parsed=%d txt=%s", id, parsed, txt)
+	}
+}
+
+// TestParseCartIdInvalid covers invalid inputs.
+func TestParseCartIdInvalid(t *testing.T) {
+	invalid := []string{
+		"",               // empty
+		" ",              // space
+		"01234567890abc", // >11 chars
+		"!!!!",           // invalid chars
+		"-underscore-",   // invalid chars
+		"abc_def",        // underscore invalid for base62
+		"0123456789ABCD", // 14 chars
+	}
+	for _, s := range invalid {
+		if _, ok := ParseCartId(s); ok {
+			t.Fatalf("expected parse failure for %q", s)
+		}
+	}
+}
+
+// TestMustParseCartIdPanics verifies panic behavior for invalid input.
+func TestMustParseCartIdPanics(t *testing.T) {
+	defer func() {
+		if r := recover(); r == nil {
+			t.Fatalf("expected panic for invalid MustParseCartId input")
+		}
+	}()
+	_ = MustParseCartId("not*base62")
+}
+
+// TestJSONMarshalUnmarshalCartId verifies JSON round trip.
+func TestJSONMarshalUnmarshalCartId(t *testing.T) {
+	id := MustNewCartId()
+	data, err := json.Marshal(struct {
+		Cart CartId `json:"cart"`
+	}{Cart: id})
+	if err != nil {
+		t.Fatalf("marshal error: %v", err)
+	}
+	var out struct {
+		Cart CartId `json:"cart"`
+	}
+	if err := json.Unmarshal(data, &out); err != nil {
+		t.Fatalf("unmarshal error: %v", err)
+	}
+	if out.Cart != id {
+		t.Fatalf("JSON round trip mismatch: have %d got %d", id, out.Cart)
+	}
+}
+
+// TestBase62LengthBound checks worst-case length (near max uint64).
+func TestBase62LengthBound(t *testing.T) {
+	// Largest uint64
+	const maxU64 = ^uint64(0)
+	s := encodeBase62(maxU64)
+	if len(s) > 11 {
+		t.Fatalf("max uint64 encoded length > 11: %d (%s)", len(s), s)
+	}
+	dec, ok := decodeBase62(s)
+	if !ok || dec != maxU64 {
+		t.Fatalf("decode failed for max uint64: ok=%v dec=%d want=%d", ok, dec, maxU64)
+	}
+}
+
+// TestZeroEncoding ensures zero value encodes to "0" and parses back.
+func TestZeroEncoding(t *testing.T) {
+	if s := encodeBase62(0); s != "0" {
+		t.Fatalf("encodeBase62(0) expected '0', got %q", s)
+	}
+	v, ok := decodeBase62("0")
+	if !ok || v != 0 {
+		t.Fatalf("decodeBase62('0') failed: ok=%v v=%d", ok, v)
+	}
+	if _, ok := ParseCartId("0"); !ok {
+		t.Fatalf("ParseCartId(\"0\") should succeed")
+	}
+}
+
+// TestSequentialParse ensures sequentially generated ids parse correctly.
+func TestSequentialParse(t *testing.T) {
+	for i := 0; i < 1000; i++ {
+		id := MustNewCartId()
+		txt := id.String()
+		parsed, ok := ParseCartId(txt)
+		if !ok || parsed != id {
+			t.Fatalf("sequential parse mismatch: idx=%d orig=%d parsed=%d txt=%s", i, id, parsed, txt)
+		}
+	}
+}
+
+// BenchmarkNewCartId measures generation performance.
+func BenchmarkNewCartId(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		if _, err := NewCartId(); err != nil {
+			b.Fatalf("NewCartId error: %v", err)
+		}
+	}
+}
+
+// BenchmarkEncodeBase62 measures encoding performance.
+func BenchmarkEncodeBase62(b *testing.B) {
+	// Precompute sample values
+	samples := make([]uint64, 1024)
+	for i := range samples {
+		// Spread bits without crypto randomness overhead
+		samples[i] = (uint64(i) << 53) ^ (uint64(i) * 0x9E3779B185EBCA87)
+	}
+	b.ResetTimer()
+	var sink string
+	for i := 0; i < b.N; i++ {
+		sink = encodeBase62(samples[i%len(samples)])
+	}
+	_ = sink
+}
+
+// BenchmarkDecodeBase62 measures decoding performance.
+func BenchmarkDecodeBase62(b *testing.B) {
+	encoded := make([]string, 1024)
+	for i := range encoded {
+		encoded[i] = encodeBase62((uint64(i) << 32) | uint64(i))
+	}
+	b.ResetTimer()
+	var sum uint64
+	for i := 0; i < b.N; i++ {
+		v, ok := decodeBase62(encoded[i%len(encoded)])
+		if !ok {
+			b.Fatalf("decode failure for %s", encoded[i%len(encoded)])
+		}
+		sum ^= v
+	}
+	_ = sum
+}
+
+// ExampleCartIdString documents usage of CartId string form.
+func ExampleCartId_string() {
+	id := MustNewCartId()
+	fmt.Println(len(id.String()) <= 11) // outputs true
+	// Output: true
+}

pkg/cart/mutation_add_item.go

@@ -0,0 +1,102 @@
+package cart
+
+import (
+	"fmt"
+
+	messages "git.tornberg.me/go-cart-actor/pkg/messages"
+)
+
+// mutation_add_item.go
+//
+// Registers the AddItem cart mutation in the generic mutation registry.
+// This replaces the legacy switch-based logic previously found in CartGrain.Apply.
+//
+// Behavior:
+//   * Validates quantity > 0
+//   * If an item with same SKU exists -> increases quantity
+//   * Else creates a new CartItem with computed tax amounts
+//   * Totals recalculated automatically via WithTotals()
+//
+// NOTE: Any future field additions in messages.AddItem that affect pricing / tax
+// must keep this handler in sync.
+
+func AddItem(g *CartGrain, m *messages.AddItem) error {
+	if m == nil {
+		return fmt.Errorf("AddItem: nil payload")
+	}
+	if m.Quantity < 1 {
+		return fmt.Errorf("AddItem: invalid quantity %d", m.Quantity)
+	}
+
+	// Merge with any existing item having same SKU and matching StoreId (including both nil).
+	for _, existing := range g.Items {
+		if existing.Sku != m.Sku {
+			continue
+		}
+		sameStore := (existing.StoreId == nil && m.StoreId == nil) ||
+			(existing.StoreId != nil && m.StoreId != nil && *existing.StoreId == *m.StoreId)
+		if !sameStore {
+			continue
+		}
+		existing.Quantity += int(m.Quantity)
+		existing.Stock = StockStatus(m.Stock)
+		// If existing had nil store but new has one, adopt it.
+		if existing.StoreId == nil && m.StoreId != nil {
+			existing.StoreId = m.StoreId
+		}
+		return nil
+	}
+
+	g.mu.Lock()
+	defer g.mu.Unlock()
+
+	g.lastItemId++
+	taxRate := float32(25.0)
+	if m.Tax > 0 {
+		taxRate = float32(int(m.Tax) / 100)
+	}
+
+	pricePerItem := NewPriceFromIncVat(m.Price, taxRate)
+
+	g.Items = append(g.Items, &CartItem{
+		Id:       g.lastItemId,
+		ItemId:   uint32(m.ItemId),
+		Quantity: int(m.Quantity),
+		Sku:      m.Sku,
+		Meta: &ItemMeta{
+			Name:       m.Name,
+			Image:      m.Image,
+			Brand:      m.Brand,
+			Category:   m.Category,
+			Category2:  m.Category2,
+			Category3:  m.Category3,
+			Category4:  m.Category4,
+			Category5:  m.Category5,
+			Outlet:     m.Outlet,
+			SellerId:   m.SellerId,
+			SellerName: m.SellerName,
+		},
+		SaleStatus: m.SaleStatus,
+		ParentId:   m.ParentId,
+
+		Price:      *pricePerItem,
+		TotalPrice: *MultiplyPrice(*pricePerItem, int64(m.Quantity)),
+
+		Stock:      StockStatus(m.Stock),
+		Disclaimer: m.Disclaimer,
+
+		OrgPrice:    getOrgPrice(m.OrgPrice, taxRate),
+		ArticleType: m.ArticleType,
+
+		StoreId: m.StoreId,
+	})
+	g.UpdateTotals()
+	return nil
+}
+
+func getOrgPrice(orgPrice int64, taxRate float32) *Price {
+	if orgPrice <= 0 {
+		return nil
+	}
+	return NewPriceFromIncVat(orgPrice, taxRate)
+}

pkg/cart/mutation_add_voucher.go

@@ -0,0 +1,66 @@
+package cart
+
+import (
+	"slices"
+
+	"git.tornberg.me/go-cart-actor/pkg/actor"
+	"git.tornberg.me/go-cart-actor/pkg/messages"
+)
+
+func RemoveVoucher(g *CartGrain, m *messages.RemoveVoucher) error {
+	if m == nil {
+		return &actor.MutationError{
+			Message:    "RemoveVoucher: nil payload",
+			Code:       1003,
+			StatusCode: 400,
+		}
+	}
+
+	if !slices.ContainsFunc(g.Vouchers, func(v *Voucher) bool {
+		return v.Id == m.Id
+	}) {
+		return &actor.MutationError{
+			Message:    "voucher not applied",
+			Code:       1004,
+			StatusCode: 400,
+		}
+	}
+
+	g.Vouchers = slices.DeleteFunc(g.Vouchers, func(v *Voucher) bool {
+		return v.Id == m.Id
+	})
+	g.UpdateTotals()
+	return nil
+}
+
+func AddVoucher(g *CartGrain, m *messages.AddVoucher) error {
+	if m == nil {
+		return &actor.MutationError{
+			Message:    "AddVoucher: nil payload",
+			Code:       1001,
+			StatusCode: 400,
+		}
+	}
+
+	if slices.ContainsFunc(g.Vouchers, func(v *Voucher) bool {
+		return v.Code == m.Code
+	}) {
+		return &actor.MutationError{
+			Message:    "voucher already applied",
+			Code:       1002,
+			StatusCode: 400,
+		}
+	}
+
+	g.lastVoucherId++
+	g.Vouchers = append(g.Vouchers, &Voucher{
+		Id:          g.lastVoucherId,
+		Applied:     false,
+		Description: m.Description,
+		Code:        m.Code,
+		Rules:       m.VoucherRules,
+		Value:       m.Value,
+	})
+	g.UpdateTotals()
+	return nil
+}

pkg/cart/mutation_change_quantity.go

@@ -1,9 +1,9 @@
-package main
+package cart
 
 import (
 	"fmt"
 
-	messages "git.tornberg.me/go-cart-actor/proto"
+	messages "git.tornberg.me/go-cart-actor/pkg/messages"
 )
 
 // mutation_change_quantity.go
@@ -25,17 +25,15 @@ import (
 //     the grain's implicit expectation that higher layers control access.
 //     (If strict locking is required around every mutation, wrap logic in
 //     an explicit g.mu.Lock()/Unlock(), but current model mirrors prior code.)
-func init() {
+
-	RegisterMutation[messages.ChangeQuantity](
+func ChangeQuantity(g *CartGrain, m *messages.ChangeQuantity) error {
-		"ChangeQuantity",
-		func(g *CartGrain, m *messages.ChangeQuantity) error {
 	if m == nil {
 		return fmt.Errorf("ChangeQuantity: nil payload")
 	}
 
 	foundIndex := -1
 	for i, it := range g.Items {
-				if it.Id == int(m.Id) {
+		if it.Id == uint32(m.Id) {
 			foundIndex = i
 			break
 		}
@@ -47,12 +45,11 @@ func init() {
 	if m.Quantity <= 0 {
 		// Remove the item
 		g.Items = append(g.Items[:foundIndex], g.Items[foundIndex+1:]...)
+		g.UpdateTotals()
 		return nil
 	}
 
 	g.Items[foundIndex].Quantity = int(m.Quantity)
+	g.UpdateTotals()
 	return nil
-		},
-		WithTotals(),
-	)
 }

pkg/cart/mutation_initialize_checkout.go

@@ -1,9 +1,9 @@
-package main
+package cart
 
 import (
 	"fmt"
 
-	messages "git.tornberg.me/go-cart-actor/proto"
+	messages "git.tornberg.me/go-cart-actor/pkg/messages"
 )
 
 // mutation_initialize_checkout.go
@@ -28,10 +28,8 @@ import (
 //     parallel checkout attempts are possible, add higher-level guards
 //     (e.g. reject if PaymentInProgress already true unless reusing
 //     the same OrderReference).
-func init() {
+
-	RegisterMutation[messages.InitializeCheckout](
+func InitializeCheckout(g *CartGrain, m *messages.InitializeCheckout) error {
-		"InitializeCheckout",
-		func(g *CartGrain, m *messages.InitializeCheckout) error {
 	if m == nil {
 		return fmt.Errorf("InitializeCheckout: nil payload")
 	}
@@ -43,7 +41,4 @@ func init() {
 	g.PaymentStatus = m.Status
 	g.PaymentInProgress = m.PaymentInProgress
 	return nil
-		},
-		// No WithTotals(): monetary aggregates are unaffected.
-	)
 }

pkg/cart/mutation_order_created.go

@@ -1,9 +1,9 @@
-package main
+package cart
 
 import (
 	"fmt"
 
-	messages "git.tornberg.me/go-cart-actor/proto"
+	messages "git.tornberg.me/go-cart-actor/pkg/messages"
 )
 
 // mutation_order_created.go
@@ -32,10 +32,8 @@ import (
 //   - Relies on the higher-level guarantee that Apply() calls are serialized
 //     per grain. If out-of-order events are possible, embed versioning or
 //     timestamps in the mutation and compare before applying changes.
-func init() {
+
-	RegisterMutation[messages.OrderCreated](
+func OrderCreated(g *CartGrain, m *messages.OrderCreated) error {
-		"OrderCreated",
-		func(g *CartGrain, m *messages.OrderCreated) error {
 	if m == nil {
 		return fmt.Errorf("OrderCreated: nil payload")
 	}
@@ -47,7 +45,4 @@ func init() {
 	g.PaymentStatus = m.Status
 	g.PaymentInProgress = false
 	return nil
-		},
-		// No WithTotals(): order completion does not modify pricing or taxes.
-	)
 }

pkg/cart/mutation_precondition.go

@@ -0,0 +1,7 @@
+package cart
+
+import messages "git.tornberg.me/go-cart-actor/pkg/messages"
+
+func PreConditionFailed(g *CartGrain, m *messages.PreConditionFailed) error {
+	return nil
+}

pkg/cart/mutation_remove_delivery.go

@@ -1,9 +1,9 @@
-package main
+package cart
 
 import (
 	"fmt"
 
-	messages "git.tornberg.me/go-cart-actor/proto"
+	messages "git.tornberg.me/go-cart-actor/pkg/messages"
 )
 
 // mutation_remove_delivery.go
@@ -25,14 +25,12 @@ import (
 // Future considerations:
 //   - If delivery pricing logic changes (e.g., dynamic taxes per delivery),
 //     UpdateTotals() may need enhancement to incorporate delivery tax properly.
-func init() {
+
-	RegisterMutation[messages.RemoveDelivery](
+func RemoveDelivery(g *CartGrain, m *messages.RemoveDelivery) error {
-		"RemoveDelivery",
-		func(g *CartGrain, m *messages.RemoveDelivery) error {
 	if m == nil {
 		return fmt.Errorf("RemoveDelivery: nil payload")
 	}
-			targetID := int(m.Id)
+	targetID := uint32(m.Id)
 	index := -1
 	for i, d := range g.Deliveries {
 		if d.Id == targetID {
@@ -46,8 +44,6 @@ func init() {
 
 	// Remove delivery (order not preserved beyond necessity)
 	g.Deliveries = append(g.Deliveries[:index], g.Deliveries[index+1:]...)
+	g.UpdateTotals()
 	return nil
-		},
-		WithTotals(),
-	)
 }

pkg/cart/mutation_remove_item.go

@@ -1,9 +1,9 @@
-package main
+package cart
 
 import (
 	"fmt"
 
-	messages "git.tornberg.me/go-cart-actor/proto"
+	messages "git.tornberg.me/go-cart-actor/pkg/messages"
 )
 
 // mutation_remove_item.go
@@ -21,14 +21,12 @@ import (
 //     semantics require pruning delivery.item_ids you can extend this handler.
 //   - If multiple lines somehow shared the same Id (should not happen), only
 //     the first match would be removed—data integrity relies on unique line Ids.
-func init() {
+
-	RegisterMutation[messages.RemoveItem](
+func RemoveItem(g *CartGrain, m *messages.RemoveItem) error {
-		"RemoveItem",
-		func(g *CartGrain, m *messages.RemoveItem) error {
 	if m == nil {
 		return fmt.Errorf("RemoveItem: nil payload")
 	}
-			targetID := int(m.Id)
+	targetID := uint32(m.Id)
 
 	index := -1
 	for i, it := range g.Items {
@@ -42,8 +40,6 @@ func init() {
 	}
 
 	g.Items = append(g.Items[:index], g.Items[index+1:]...)
+	g.UpdateTotals()
 	return nil
-		},
-		WithTotals(),
-	)
 }

pkg/cart/mutation_set_delivery.go

@@ -0,0 +1,96 @@
+package cart
+
+import (
+	"fmt"
+	"slices"
+
+	messages "git.tornberg.me/go-cart-actor/pkg/messages"
+)
+
+// mutation_set_delivery.go
+//
+// Registers the SetDelivery mutation.
+//
+// Semantics (mirrors legacy switch logic):
+//   - If the payload specifies an explicit list of item IDs (payload.Items):
+//   - Each referenced cart line must exist.
+//   - None of the referenced items may already belong to a delivery.
+//   - Only those items are associated with the new delivery.
+//   - If payload.Items is empty:
+//   - All items currently without any delivery are associated with the new delivery.
+//   - A new delivery line is created with:
+//   - Auto-incremented delivery ID (cart-local)
+//   - Provider from payload
+//   - Fixed price (currently hard-coded: 4900 minor units) – adjust as needed
+//   - Optional PickupPoint copied from payload
+//   - Cart totals are recalculated (WithTotals)
+//
+// Error cases:
+//   - Referenced item does not exist
+//   - Referenced item already has a delivery
+//   - No items qualify (resulting association set empty) -> returns error (prevents creating empty delivery)
+//
+// Concurrency:
+//   - Uses g.mu to protect lastDeliveryId increment and append to Deliveries slice.
+//     Item scans are read-only and performed outside the lock for simplicity;
+//     if stricter guarantees are needed, widen the lock section.
+//
+// Future extension points:
+//   - Variable delivery pricing (based on weight, distance, provider, etc.)
+//   - Validation of provider codes
+//   - Multi-currency delivery pricing
+
+func SetDelivery(g *CartGrain, m *messages.SetDelivery) error {
+	if m == nil {
+		return fmt.Errorf("SetDelivery: nil payload")
+	}
+	if m.Provider == "" {
+		return fmt.Errorf("SetDelivery: provider is empty")
+	}
+
+	withDelivery := g.ItemsWithDelivery()
+	targetItems := make([]uint32, 0)
+
+	if len(m.Items) == 0 {
+		// Use every item currently without a delivery
+		targetItems = append(targetItems, g.ItemsWithoutDelivery()...)
+	} else {
+		// Validate explicit list
+		for _, id64 := range m.Items {
+			id := uint32(id64)
+			found := false
+			for _, it := range g.Items {
+				if it.Id == id {
+					found = true
+					break
+				}
+			}
+			if !found {
+				return fmt.Errorf("SetDelivery: item id %d not found", id)
+			}
+			if slices.Contains(withDelivery, id) {
+				return fmt.Errorf("SetDelivery: item id %d already has a delivery", id)
+			}
+			targetItems = append(targetItems, id)
+		}
+	}
+
+	if len(targetItems) == 0 {
+		return fmt.Errorf("SetDelivery: no eligible items to attach")
+	}
+
+	// Append new delivery
+	g.mu.Lock()
+	g.lastDeliveryId++
+	newId := g.lastDeliveryId
+	g.Deliveries = append(g.Deliveries, &CartDelivery{
+		Id:          newId,
+		Provider:    m.Provider,
+		PickupPoint: m.PickupPoint,
+		Price:       *NewPriceFromIncVat(4900, 25.0),
+		Items:       targetItems,
+	})
+	g.mu.Unlock()
+
+	return nil
+}

pkg/cart/mutation_set_pickup_point.go

@@ -1,9 +1,9 @@
-package main
+package cart
 
 import (
 	"fmt"
 
-	messages "git.tornberg.me/go-cart-actor/proto"
+	messages "git.tornberg.me/go-cart-actor/pkg/messages"
 )
 
 // mutation_set_pickup_point.go
@@ -28,16 +28,14 @@ import (
 //   - Validate pickup point fields (country code, zip format, etc.)
 //   - Track history / audit of pickup point changes
 //   - Trigger delivery price adjustments (which would then require WithTotals()).
-func init() {
+
-	RegisterMutation[messages.SetPickupPoint](
+func SetPickupPoint(g *CartGrain, m *messages.SetPickupPoint) error {
-		"SetPickupPoint",
-		func(g *CartGrain, m *messages.SetPickupPoint) error {
 	if m == nil {
 		return fmt.Errorf("SetPickupPoint: nil payload")
 	}
 
 	for _, d := range g.Deliveries {
-				if d.Id == int(m.DeliveryId) {
+		if d.Id == uint32(m.DeliveryId) {
 			d.PickupPoint = &messages.PickupPoint{
 				Id:      m.Id,
 				Name:    m.Name,
@@ -50,7 +48,15 @@ func init() {
 		}
 	}
 	return fmt.Errorf("SetPickupPoint: delivery id %d not found", m.DeliveryId)
-		},
+}
-		// No WithTotals(): pickup point does not change pricing / tax.
+
-	)
+func ClearCart(g *CartGrain, m *messages.ClearCartRequest) error {
+	if m == nil {
+		return fmt.Errorf("ClearCart: nil payload")
+	}
+	// maybe check if payment is done?
+	g.Deliveries = g.Deliveries[:0]
+	g.Items = g.Items[:0]
+	g.UpdateTotals()
+	return nil
 }

pkg/cart/mutation_test.go

@@ -0,0 +1,520 @@
+package cart
+
+import (
+	"reflect"
+	"slices"
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/gogo/protobuf/proto"
+	anypb "google.golang.org/protobuf/types/known/anypb"
+
+	"git.tornberg.me/go-cart-actor/pkg/actor"
+	messages "git.tornberg.me/go-cart-actor/pkg/messages"
+)
+
+// ----------------------
+// Helper constructors
+// ----------------------
+
+func newTestGrain() *CartGrain {
+	return NewCartGrain(123, time.Now())
+}
+
+func newRegistry() actor.MutationRegistry {
+	return NewCartMultationRegistry()
+}
+
+func msgAddItem(sku string, price int64, qty int32, storePtr *string) *messages.AddItem {
+	return &messages.AddItem{
+		Sku:      sku,
+		Price:    price,
+		Quantity: qty,
+		// Tax left 0 -> handler uses default 25%
+		StoreId: storePtr,
+	}
+}
+
+func msgChangeQty(id uint32, qty int32) *messages.ChangeQuantity {
+	return &messages.ChangeQuantity{Id: id, Quantity: qty}
+}
+
+func msgRemoveItem(id uint32) *messages.RemoveItem {
+	return &messages.RemoveItem{Id: id}
+}
+
+func msgSetDelivery(provider string, items ...uint32) *messages.SetDelivery {
+	uitems := make([]uint32, len(items))
+	copy(uitems, items)
+	return &messages.SetDelivery{Provider: provider, Items: uitems}
+}
+
+func msgSetPickupPoint(deliveryId uint32, id string) *messages.SetPickupPoint {
+	return &messages.SetPickupPoint{
+		DeliveryId: deliveryId,
+		Id:         id,
+		Name:       ptr("Pickup"),
+		Address:    ptr("Street 1"),
+		City:       ptr("Town"),
+		Zip:        ptr("12345"),
+		Country:    ptr("SE"),
+	}
+}
+
+func msgClearCart() *messages.ClearCartRequest {
+	return &messages.ClearCartRequest{}
+}
+
+func msgAddVoucher(code string, value int64, rules ...string) *messages.AddVoucher {
+	return &messages.AddVoucher{Code: code, Value: value, VoucherRules: rules}
+}
+
+func msgRemoveVoucher(id uint32) *messages.RemoveVoucher {
+	return &messages.RemoveVoucher{Id: id}
+}
+
+func msgInitializeCheckout(orderId, status string, inProgress bool) *messages.InitializeCheckout {
+	return &messages.InitializeCheckout{OrderId: orderId, Status: status, PaymentInProgress: inProgress}
+}
+
+func msgOrderCreated(orderId, status string) *messages.OrderCreated {
+	return &messages.OrderCreated{OrderId: orderId, Status: status}
+}
+
+func ptr[T any](v T) *T { return &v }
+
+// ----------------------
+// Apply helpers
+// ----------------------
+
+func applyOne(t *testing.T, reg actor.MutationRegistry, g *CartGrain, msg proto.Message) actor.ApplyResult {
+	t.Helper()
+	results, err := reg.Apply(g, msg)
+	if err != nil {
+		t.Fatalf("unexpected registry-level error applying %T: %v", msg, err)
+	}
+	if len(results) != 1 {
+		t.Fatalf("expected exactly one ApplyResult, got %d", len(results))
+	}
+	return results[0]
+}
+
+// Expect success (nil error inside ApplyResult).
+func applyOK(t *testing.T, reg actor.MutationRegistry, g *CartGrain, msg proto.Message) {
+	t.Helper()
+	res := applyOne(t, reg, g, msg)
+	if res.Error != nil {
+		t.Fatalf("expected mutation %s (%T) to succeed, got error: %v", res.Type, msg, res.Error)
+	}
+}
+
+// Expect an error matching substring.
+func applyErrorContains(t *testing.T, reg actor.MutationRegistry, g *CartGrain, msg proto.Message, substr string) {
+	t.Helper()
+	res := applyOne(t, reg, g, msg)
+	if res.Error == nil {
+		t.Fatalf("expected error applying %T, got nil", msg)
+	}
+	if substr != "" && !strings.Contains(res.Error.Error(), substr) {
+		t.Fatalf("error mismatch, want substring %q got %q", substr, res.Error.Error())
+	}
+}
+
+// ----------------------
+// Tests
+// ----------------------
+
+func TestMutationRegistryCoverage(t *testing.T) {
+	reg := newRegistry()
+
+	expected := []string{
+		"AddItem",
+		"ChangeQuantity",
+		"RemoveItem",
+		"InitializeCheckout",
+		"OrderCreated",
+		"RemoveDelivery",
+		"SetDelivery",
+		"SetPickupPoint",
+		"ClearCartRequest",
+		"AddVoucher",
+		"RemoveVoucher",
+		"UpsertSubscriptionDetails",
+	}
+
+	names := reg.(*actor.ProtoMutationRegistry).RegisteredMutations()
+	for _, want := range expected {
+		if !slices.Contains(names, want) {
+			t.Fatalf("registry missing mutation %s; got %v", want, names)
+		}
+	}
+
+	// Create() by name returns correct concrete type.
+	for _, name := range expected {
+		msg, ok := reg.Create(name)
+		if !ok {
+			t.Fatalf("Create failed for %s", name)
+		}
+		rt := reflect.TypeOf(msg)
+		if rt.Kind() == reflect.Ptr {
+			rt = rt.Elem()
+		}
+		if rt.Name() != name {
+			t.Fatalf("Create(%s) returned wrong type %s", name, rt.Name())
+		}
+	}
+
+	// Unregistered create
+	if m, ok := reg.Create("DoesNotExist"); ok || m != nil {
+		t.Fatalf("Create should fail for unknown; got (%T,%v)", m, ok)
+	}
+
+	// GetTypeName sanity
+	add := &messages.AddItem{}
+	nm, ok := reg.GetTypeName(add)
+	if !ok || nm != "AddItem" {
+		t.Fatalf("GetTypeName failed for AddItem, got (%q,%v)", nm, ok)
+	}
+
+	// Apply unregistered message -> result should contain ErrMutationNotRegistered, no top-level error
+	results, err := reg.Apply(newTestGrain(), &messages.Noop{})
+	if err != nil {
+		t.Fatalf("unexpected top-level error applying unregistered mutation: %v", err)
+	}
+	if len(results) != 1 || results[0].Error == nil || results[0].Error != actor.ErrMutationNotRegistered {
+		t.Fatalf("expected ApplyResult with ErrMutationNotRegistered, got %#v", results)
+	}
+}
+
+func TestAddItemAndMerging(t *testing.T) {
+	reg := newRegistry()
+	g := newTestGrain()
+
+	// Merge scenario (same SKU + same store pointer)
+	add1 := msgAddItem("SKU-1", 1000, 2, nil)
+	applyOK(t, reg, g, add1)
+
+	if len(g.Items) != 1 || g.Items[0].Quantity != 2 {
+		t.Fatalf("expected first item added; items=%d qty=%d", len(g.Items), g.Items[0].Quantity)
+	}
+
+	applyOK(t, reg, g, msgAddItem("SKU-1", 1000, 3, nil)) // should merge
+	if len(g.Items) != 1 || g.Items[0].Quantity != 5 {
+		t.Fatalf("expected merge quantity=5 items=%d qty=%d", len(g.Items), g.Items[0].Quantity)
+	}
+
+	// Different store pointer -> new line
+	store := "S1"
+	applyOK(t, reg, g, msgAddItem("SKU-1", 1000, 1, &store))
+	if len(g.Items) != 2 {
+		t.Fatalf("expected second line for different store pointer; items=%d", len(g.Items))
+	}
+
+	// Same store pointer & SKU -> merge with second line
+	applyOK(t, reg, g, msgAddItem("SKU-1", 1000, 4, &store))
+	if len(g.Items) != 2 || g.Items[1].Quantity != 5 {
+		t.Fatalf("expected merge on second line; items=%d second.qty=%d", len(g.Items), g.Items[1].Quantity)
+	}
+
+	// Invalid quantity
+	applyErrorContains(t, reg, g, msgAddItem("BAD", 1000, 0, nil), "invalid quantity")
+}
+
+func TestChangeQuantityBehavior(t *testing.T) {
+	reg := newRegistry()
+	g := newTestGrain()
+
+	applyOK(t, reg, g, msgAddItem("A", 1500, 2, nil))
+	id := g.Items[0].Id
+
+	// Increase quantity
+	applyOK(t, reg, g, msgChangeQty(id, 5))
+	if g.Items[0].Quantity != 5 {
+		t.Fatalf("quantity not updated expected=5 got=%d", g.Items[0].Quantity)
+	}
+
+	// Remove item by setting <=0
+	applyOK(t, reg, g, msgChangeQty(id, 0))
+	if len(g.Items) != 0 {
+		t.Fatalf("expected item removed; items=%d", len(g.Items))
+	}
+
+	// Not found
+	applyErrorContains(t, reg, g, msgChangeQty(9999, 1), "not found")
+}
+
+func TestRemoveItemBehavior(t *testing.T) {
+	reg := newRegistry()
+	g := newTestGrain()
+
+	applyOK(t, reg, g, msgAddItem("X", 1200, 1, nil))
+	id := g.Items[0].Id
+
+	applyOK(t, reg, g, msgRemoveItem(id))
+	if len(g.Items) != 0 {
+		t.Fatalf("expected item removed; items=%d", len(g.Items))
+	}
+
+	applyErrorContains(t, reg, g, msgRemoveItem(id), "not found")
+}
+
+func TestDeliveryMutations(t *testing.T) {
+	reg := newRegistry()
+	g := newTestGrain()
+
+	applyOK(t, reg, g, msgAddItem("D1", 1000, 1, nil))
+	applyOK(t, reg, g, msgAddItem("D2", 2000, 1, nil))
+	i1 := g.Items[0].Id
+
+	// Explicit items
+	applyOK(t, reg, g, msgSetDelivery("POSTNORD", i1))
+	if len(g.Deliveries) != 1 || len(g.Deliveries[0].Items) != 1 || g.Deliveries[0].Items[0] != i1 {
+		t.Fatalf("delivery not created as expected: %+v", g.Deliveries)
+	}
+
+	// Attempt to attach an already-delivered item
+	applyErrorContains(t, reg, g, msgSetDelivery("POSTNORD", i1), "already has a delivery")
+
+	// Attach remaining item via empty list (auto include items without delivery)
+	applyOK(t, reg, g, msgSetDelivery("DHL"))
+	if len(g.Deliveries) != 2 {
+		t.Fatalf("expected second delivery; deliveries=%d", len(g.Deliveries))
+	}
+
+	// Non-existent item
+	applyErrorContains(t, reg, g, msgSetDelivery("UPS", 99999), "not found")
+
+	// No eligible items left
+	applyErrorContains(t, reg, g, msgSetDelivery("UPS"), "no eligible items")
+
+	// Set pickup point on first delivery
+	did := g.Deliveries[0].Id
+	applyOK(t, reg, g, msgSetPickupPoint(did, "PP1"))
+	if g.Deliveries[0].PickupPoint == nil || g.Deliveries[0].PickupPoint.Id != "PP1" {
+		t.Fatalf("pickup point not set correctly: %+v", g.Deliveries[0].PickupPoint)
+	}
+
+	// Bad delivery id
+	applyErrorContains(t, reg, g, msgSetPickupPoint(9999, "PPX"), "delivery id")
+
+	// Remove delivery
+	applyOK(t, reg, g, &messages.RemoveDelivery{Id: did})
+	if len(g.Deliveries) != 1 || g.Deliveries[0].Id == did {
+		t.Fatalf("expected first delivery removed, remaining: %+v", g.Deliveries)
+	}
+
+	// Remove delivery not found
+	applyErrorContains(t, reg, g, &messages.RemoveDelivery{Id: did}, "not found")
+}
+
+func TestClearCart(t *testing.T) {
+	reg := newRegistry()
+	g := newTestGrain()
+
+	applyOK(t, reg, g, msgAddItem("X", 1000, 2, nil))
+	applyOK(t, reg, g, msgSetDelivery("P", g.Items[0].Id))
+
+	applyOK(t, reg, g, msgClearCart())
+
+	if len(g.Items) != 0 || len(g.Deliveries) != 0 {
+		t.Fatalf("expected cart cleared; items=%d deliveries=%d", len(g.Items), len(g.Deliveries))
+	}
+}
+
+func TestVoucherMutations(t *testing.T) {
+	reg := newRegistry()
+	g := newTestGrain()
+
+	applyOK(t, reg, g, msgAddItem("VOUCH", 10000, 1, nil))
+	applyOK(t, reg, g, msgAddVoucher("PROMO", 5000))
+
+	if len(g.Vouchers) != 1 {
+		t.Fatalf("voucher not stored")
+	}
+	if g.TotalDiscount.IncVat != 5000 {
+		t.Fatalf("expected discount 5000 got %d", g.TotalDiscount.IncVat)
+	}
+	if g.TotalPrice.IncVat != 5000 {
+		t.Fatalf("expected total price 5000 got %d", g.TotalPrice.IncVat)
+	}
+
+	// Duplicate voucher code
+	applyErrorContains(t, reg, g, msgAddVoucher("PROMO", 1000), "already applied")
+
+	// Add a large voucher (should not apply because value > total price)
+	applyOK(t, reg, g, msgAddVoucher("BIG", 100000))
+	if len(g.Vouchers) != 2 {
+		t.Fatalf("expected second voucher stored")
+	}
+	if g.TotalDiscount.IncVat != 5000 || g.TotalPrice.IncVat != 5000 {
+		t.Fatalf("large voucher incorrectly applied discount=%d total=%d",
+			g.TotalDiscount.IncVat, g.TotalPrice.IncVat)
+	}
+
+	// Remove existing voucher
+	firstId := g.Vouchers[0].Id
+	applyOK(t, reg, g, msgRemoveVoucher(firstId))
+
+	if slices.ContainsFunc(g.Vouchers, func(v *Voucher) bool { return v.Id == firstId }) {
+		t.Fatalf("voucher id %d not removed", firstId)
+	}
+	// After removing PROMO, BIG remains but is not applied (exceeds price)
+	if g.TotalDiscount.IncVat != 0 || g.TotalPrice.IncVat != 10000 {
+		t.Fatalf("totals incorrect after removal discount=%d total=%d",
+			g.TotalDiscount.IncVat, g.TotalPrice.IncVat)
+	}
+
+	// Remove not applied
+	applyErrorContains(t, reg, g, msgRemoveVoucher(firstId), "not applied")
+}
+
+func TestCheckoutMutations(t *testing.T) {
+	reg := newRegistry()
+	g := newTestGrain()
+
+	applyOK(t, reg, g, msgInitializeCheckout("ORD-1", "PENDING", true))
+	if g.OrderReference != "ORD-1" || g.PaymentStatus != "PENDING" || !g.PaymentInProgress {
+		t.Fatalf("initialize checkout failed: ref=%s status=%s inProgress=%v",
+			g.OrderReference, g.PaymentStatus, g.PaymentInProgress)
+	}
+
+	applyOK(t, reg, g, msgOrderCreated("ORD-1", "COMPLETED"))
+	if g.OrderReference != "ORD-1" || g.PaymentStatus != "COMPLETED" || g.PaymentInProgress {
+		t.Fatalf("order created mutation failed: ref=%s status=%s inProgress=%v",
+			g.OrderReference, g.PaymentStatus, g.PaymentInProgress)
+	}
+
+	applyErrorContains(t, reg, g, msgInitializeCheckout("", "X", true), "missing orderId")
+	applyErrorContains(t, reg, g, msgOrderCreated("", "X"), "missing orderId")
+}
+
+func TestSubscriptionDetailsMutation(t *testing.T) {
+	reg := newRegistry()
+	g := newTestGrain()
+
+	// Upsert new (Id == nil)
+	msgNew := &messages.UpsertSubscriptionDetails{
+		OfferingCode: "OFF1",
+		SigningType:  "TYPE1",
+	}
+	applyOK(t, reg, g, msgNew)
+	if len(g.SubscriptionDetails) != 1 {
+		t.Fatalf("expected one subscription detail; got=%d", len(g.SubscriptionDetails))
+	}
+
+	// Capture created id
+	var createdId string
+	for k := range g.SubscriptionDetails {
+		createdId = k
+	}
+
+	// Update existing
+	msgUpdate := &messages.UpsertSubscriptionDetails{
+		Id:           &createdId,
+		OfferingCode: "OFF2",
+		SigningType:  "TYPE2",
+	}
+	applyOK(t, reg, g, msgUpdate)
+	if g.SubscriptionDetails[createdId].OfferingCode != "OFF2" ||
+		g.SubscriptionDetails[createdId].SigningType != "TYPE2" {
+		t.Fatalf("subscription details not updated: %+v", g.SubscriptionDetails[createdId])
+	}
+
+	// Update non-existent
+	badId := "NON_EXISTENT"
+	applyErrorContains(t, reg, g, &messages.UpsertSubscriptionDetails{Id: &badId}, "not found")
+
+	// Nil mutation should be ignored and produce zero results.
+	resultsNil, errNil := reg.Apply(g, (*messages.UpsertSubscriptionDetails)(nil))
+	if errNil != nil {
+		t.Fatalf("unexpected error for nil mutation element: %v", errNil)
+	}
+	if len(resultsNil) != 0 {
+		t.Fatalf("expected zero results for nil mutation, got %d", len(resultsNil))
+	}
+}
+
+// Ensure registry Apply handles nil grain and nil message defensive errors consistently.
+func TestRegistryDefensiveErrors(t *testing.T) {
+	reg := newRegistry()
+	g := newTestGrain()
+
+	// Nil grain
+	results, err := reg.Apply(nil, &messages.AddItem{})
+	if err == nil {
+		t.Fatalf("expected error for nil grain")
+	}
+	if len(results) != 0 {
+		t.Fatalf("expected no results for nil grain")
+	}
+
+	// Nil message slice
+	results, _ = reg.Apply(g, nil)
+
+	if len(results) != 0 {
+		t.Fatalf("expected no results when message slice nil")
+	}
+}
+func TestSubscriptionDetailsJSONValidation(t *testing.T) {
+	reg := newRegistry()
+	g := newTestGrain()
+
+	// Valid JSON on create
+	validCreate := &messages.UpsertSubscriptionDetails{
+		OfferingCode: "OFFJSON",
+		SigningType:  "TYPEJSON",
+		Data:         &anypb.Any{Value: []byte(`{"ok":true}`)},
+	}
+	applyOK(t, reg, g, validCreate)
+	if len(g.SubscriptionDetails) != 1 {
+		t.Fatalf("expected one subscription detail after valid create, got %d", len(g.SubscriptionDetails))
+	}
+	var id string
+	for k := range g.SubscriptionDetails {
+		id = k
+	}
+	if string(g.SubscriptionDetails[id].Meta) != `{"ok":true}` {
+		t.Fatalf("expected meta stored as valid json, got %s", string(g.SubscriptionDetails[id].Meta))
+	}
+
+	// Update with valid JSON replaces meta
+	updateValid := &messages.UpsertSubscriptionDetails{
+		Id:   &id,
+		Data: &anypb.Any{Value: []byte(`{"changed":123}`)},
+	}
+	applyOK(t, reg, g, updateValid)
+	if string(g.SubscriptionDetails[id].Meta) != `{"changed":123}` {
+		t.Fatalf("expected meta updated to new json, got %s", string(g.SubscriptionDetails[id].Meta))
+	}
+
+	// Invalid JSON on create
+	invalidCreate := &messages.UpsertSubscriptionDetails{
+		OfferingCode: "BAD",
+		Data:         &anypb.Any{Value: []byte(`{"broken":}`)},
+	}
+	res := applyOne(t, reg, g, invalidCreate)
+	if res.Error == nil || !strings.Contains(res.Error.Error(), "invalid json") {
+		t.Fatalf("expected invalid json error on create, got %v", res.Error)
+	}
+
+	// Invalid JSON on update
+	badUpdate := &messages.UpsertSubscriptionDetails{
+		Id:   &id,
+		Data: &anypb.Any{Value: []byte(`{oops`)},
+	}
+	res2 := applyOne(t, reg, g, badUpdate)
+	if res2.Error == nil || !strings.Contains(res2.Error.Error(), "invalid json") {
+		t.Fatalf("expected invalid json error on update, got %v", res2.Error)
+	}
+
+	// Empty Data.Value should not overwrite existing meta
+	emptyUpdate := &messages.UpsertSubscriptionDetails{
+		Id:   &id,
+		Data: &anypb.Any{Value: []byte{}},
+	}
+	applyOK(t, reg, g, emptyUpdate)
+	if string(g.SubscriptionDetails[id].Meta) != `{"changed":123}` {
+		t.Fatalf("empty update should not change meta, got %s", string(g.SubscriptionDetails[id].Meta))
+	}
+}

pkg/cart/mutation_upsert_subscriptiondetails.go

@@ -0,0 +1,57 @@
+package cart
+
+import (
+	"encoding/json"
+	"fmt"
+
+	messages "git.tornberg.me/go-cart-actor/pkg/messages"
+)
+
+func UpsertSubscriptionDetails(g *CartGrain, m *messages.UpsertSubscriptionDetails) error {
+	if m == nil {
+		return nil
+	}
+
+	// Create new subscription details when Id is nil.
+	if m.Id == nil {
+		// Validate JSON if provided.
+		var meta json.RawMessage
+		if m.Data != nil && len(m.Data.Value) > 0 {
+			if !json.Valid(m.Data.Value) {
+				return fmt.Errorf("subscription details invalid json")
+			}
+			meta = json.RawMessage(m.Data.Value)
+		}
+
+		id := MustNewCartId().String()
+		g.SubscriptionDetails[id] = &SubscriptionDetails{
+			Id:           id,
+			OfferingCode: m.OfferingCode,
+			SigningType:  m.SigningType,
+			Meta:         meta,
+		}
+		return nil
+	}
+
+	// Update existing entry.
+	existing, ok := g.SubscriptionDetails[*m.Id]
+	if !ok {
+		return fmt.Errorf("subscription details not found")
+	}
+	if m.OfferingCode != "" {
+		existing.OfferingCode = m.OfferingCode
+	}
+	if m.SigningType != "" {
+		existing.SigningType = m.SigningType
+	}
+	if m.Data != nil {
+		// Only validate & assign if there is content; empty -> leave as-is.
+		if len(m.Data.Value) > 0 {
+			if !json.Valid(m.Data.Value) {
+				return fmt.Errorf("subscription details invalid json")
+			}
+			existing.Meta = m.Data.Value
+		}
+	}
+	return nil
+}

pkg/cart/price.go

@@ -0,0 +1,131 @@
+package cart
+
+import (
+	"encoding/json"
+	"strconv"
+)
+
+func GetTaxAmount(total int64, tax int) int64 {
+	taxD := 10000 / float64(tax)
+	return int64(float64(total) / float64((1 + taxD)))
+}
+
+type Price struct {
+	IncVat   int64             `json:"incVat"`
+	VatRates map[float32]int64 `json:"vat,omitempty"`
+}
+
+func NewPrice() *Price {
+	return &Price{
+		IncVat:   0,
+		VatRates: make(map[float32]int64),
+	}
+}
+
+func NewPriceFromIncVat(incVat int64, taxRate float32) *Price {
+	tax := GetTaxAmount(incVat, int(taxRate*100))
+	return &Price{
+		IncVat: incVat,
+		VatRates: map[float32]int64{
+			taxRate: tax,
+		},
+	}
+}
+
+func (p *Price) ValueExVat() int64 {
+	exVat := p.IncVat
+	for _, amount := range p.VatRates {
+		exVat -= amount
+	}
+	return exVat
+}
+
+func (p *Price) TotalVat() int64 {
+	total := int64(0)
+	for _, amount := range p.VatRates {
+		total += amount
+	}
+	return total
+}
+
+func MultiplyPrice(p Price, qty int64) *Price {
+	ret := &Price{
+		IncVat:   p.IncVat * qty,
+		VatRates: make(map[float32]int64),
+	}
+	for rate, amount := range p.VatRates {
+		ret.VatRates[rate] = amount * qty
+	}
+	return ret
+}
+
+func (p *Price) Multiply(qty int64) {
+	p.IncVat *= qty
+	for rate, amount := range p.VatRates {
+		p.VatRates[rate] = amount * qty
+	}
+}
+
+func (p Price) MarshalJSON() ([]byte, error) {
+	// Build a stable wire format without calling Price.MarshalJSON recursively
+	exVat := p.ValueExVat()
+	var vat map[string]int64
+	if len(p.VatRates) > 0 {
+		vat = make(map[string]int64, len(p.VatRates))
+		for rate, amount := range p.VatRates {
+			// Rely on default formatting that trims trailing zeros for whole numbers
+			// Using %g could output scientific notation for large numbers; float32 rates here are small.
+			key := trimFloat(rate)
+			vat[key] = amount
+		}
+	}
+	type wire struct {
+		ExVat  int64            `json:"exVat"`
+		IncVat int64            `json:"incVat"`
+		Vat    map[string]int64 `json:"vat,omitempty"`
+	}
+	return json.Marshal(wire{ExVat: exVat, IncVat: p.IncVat, Vat: vat})
+}
+
+// trimFloat converts a float32 tax rate like 25 or 12.5 into a compact string without
+// unnecessary decimals ("25", "12.5").
+func trimFloat(f float32) string {
+	// Convert via FormatFloat then trim trailing zeros and dot.
+	s := strconv.FormatFloat(float64(f), 'f', -1, 32)
+	return s
+}
+
+func (p *Price) Add(price Price) {
+	p.IncVat += price.IncVat
+	for rate, amount := range price.VatRates {
+		p.VatRates[rate] += amount
+	}
+}
+
+func (p *Price) Subtract(price Price) {
+	p.IncVat -= price.IncVat
+	for rate, amount := range price.VatRates {
+		p.VatRates[rate] -= amount
+	}
+}
+
+func SumPrices(prices ...Price) *Price {
+	if len(prices) == 0 {
+		return NewPrice()
+	}
+
+	aggregated := NewPrice()
+
+	for _, price := range prices {
+		aggregated.IncVat += price.IncVat
+		for rate, amount := range price.VatRates {
+			aggregated.VatRates[rate] += amount
+		}
+	}
+
+	if len(aggregated.VatRates) == 0 {
+		aggregated.VatRates = nil
+	}
+
+	return aggregated
+}

pkg/cart/price_test.go

@@ -0,0 +1,135 @@
+package cart
+
+import (
+	"encoding/json"
+	"testing"
+)
+
+func TestPriceMarshalJSON(t *testing.T) {
+	p := Price{IncVat: 13700, VatRates: map[float32]int64{25: 2500, 12: 1200}}
+	// ExVat = 13700 - (2500+1200) = 10000
+	data, err := json.Marshal(p)
+	if err != nil {
+		t.Fatalf("marshal error: %v", err)
+	}
+	// Unmarshal into a generic struct to validate fields
+	var out struct {
+		ExVat  int64            `json:"exVat"`
+		IncVat int64            `json:"incVat"`
+		Vat    map[string]int64 `json:"vat"`
+	}
+	if err := json.Unmarshal(data, &out); err != nil {
+		t.Fatalf("unmarshal error: %v", err)
+	}
+	if out.ExVat != 10000 {
+		t.Fatalf("expected exVat 10000 got %d", out.ExVat)
+	}
+	if out.IncVat != 13700 {
+		t.Fatalf("expected incVat 13700 got %d", out.IncVat)
+	}
+	if out.Vat["25"] != 2500 || out.Vat["12"] != 1200 {
+		t.Fatalf("unexpected vat map: %#v", out.Vat)
+	}
+}
+
+func TestNewPriceFromIncVat(t *testing.T) {
+	p := NewPriceFromIncVat(1250, 25)
+	if p.IncVat != 1250 {
+		t.Fatalf("expected IncVat %d got %d", 1250, p.IncVat)
+	}
+	if p.VatRates[25] != 250 {
+		t.Fatalf("expected VAT 25 rate %d got %d", 250, p.VatRates[25])
+	}
+	if p.ValueExVat() != 1000 {
+		t.Fatalf("expected exVat %d got %d", 750, p.ValueExVat())
+	}
+}
+
+func TestSumPrices(t *testing.T) {
+	// We'll construct prices via raw struct since constructor expects tax math.
+	// IncVat already includes vat portions.
+	a := Price{IncVat: 1250, VatRates: map[float32]int64{25: 250}}          // ex=1000
+	b := Price{IncVat: 2740, VatRates: map[float32]int64{25: 500, 12: 240}} // ex=2000
+	c := Price{IncVat: 0, VatRates: nil}
+
+	sum := SumPrices(a, b, c)
+
+	if sum.IncVat != 3990 { // 1250+2740
+		t.Fatalf("expected incVat 3990 got %d", sum.IncVat)
+	}
+	if len(sum.VatRates) != 2 {
+		t.Fatalf("expected 2 vat rates got %d", len(sum.VatRates))
+	}
+	if sum.VatRates[25] != 750 {
+		t.Fatalf("expected 25%% vat 750 got %d", sum.VatRates[25])
+	}
+	if sum.VatRates[12] != 240 {
+		t.Fatalf("expected 12%% vat 240 got %d", sum.VatRates[12])
+	}
+	if sum.ValueExVat() != 3000 { // 3990 - (750+240)
+		t.Fatalf("expected exVat 3000 got %d", sum.ValueExVat())
+	}
+}
+
+func TestSumPricesEmpty(t *testing.T) {
+	sum := SumPrices()
+	if sum.IncVat != 0 || sum.VatRates == nil { // constructor sets empty map
+		t.Fatalf("expected zero price got %#v", sum)
+	}
+}
+
+func TestMultiplyPriceFunction(t *testing.T) {
+	base := Price{IncVat: 1250, VatRates: map[float32]int64{25: 250}}
+	multiplied := MultiplyPrice(base, 3)
+	if multiplied.IncVat != 1250*3 {
+		t.Fatalf("expected IncVat %d got %d", 1250*3, multiplied.IncVat)
+	}
+	if multiplied.VatRates[25] != 250*3 {
+		t.Fatalf("expected VAT 25 rate %d got %d", 250*3, multiplied.VatRates[25])
+	}
+	if multiplied.ValueExVat() != (1250-250)*3 {
+		t.Fatalf("expected exVat %d got %d", (1250-250)*3, multiplied.ValueExVat())
+	}
+}
+
+func TestPriceAddSubtract(t *testing.T) {
+	a := Price{IncVat: 1000, VatRates: map[float32]int64{25: 200}}
+	b := Price{IncVat: 500, VatRates: map[float32]int64{25: 100, 12: 54}}
+
+	acc := NewPrice()
+	acc.Add(a)
+	acc.Add(b)
+
+	if acc.IncVat != 1500 {
+		t.Fatalf("expected IncVat 1500 got %d", acc.IncVat)
+	}
+	if acc.VatRates[25] != 300 || acc.VatRates[12] != 54 {
+		t.Fatalf("unexpected VAT map: %#v", acc.VatRates)
+	}
+
+	// Subtract b then a returns to zero
+	acc.Subtract(b)
+	acc.Subtract(a)
+	if acc.IncVat != 0 {
+		t.Fatalf("expected IncVat 0 got %d", acc.IncVat)
+	}
+	if len(acc.VatRates) != 2 || acc.VatRates[25] != 0 || acc.VatRates[12] != 0 {
+		t.Fatalf("expected zeroed vat rates got %#v", acc.VatRates)
+	}
+}
+
+func TestPriceMultiplyMethod(t *testing.T) {
+	p := Price{IncVat: 2000, VatRates: map[float32]int64{25: 400}}
+	// Value before multiply
+	exBefore := p.ValueExVat()
+	p.Multiply(2)
+	if p.IncVat != 4000 {
+		t.Fatalf("expected IncVat 4000 got %d", p.IncVat)
+	}
+	if p.VatRates[25] != 800 {
+		t.Fatalf("expected VAT 800 got %d", p.VatRates[25])
+	}
+	if p.ValueExVat() != exBefore*2 {
+		t.Fatalf("expected exVat %d got %d", exBefore*2, p.ValueExVat())
+	}
+}

pkg/discovery/discovery.go

@@ -0,0 +1,73 @@
+package discovery
+
+import (
+	"context"
+
+	v1 "k8s.io/api/core/v1"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/watch"
+	"k8s.io/client-go/kubernetes"
+	"k8s.io/client-go/tools/cache"
+	toolsWatch "k8s.io/client-go/tools/watch"
+)
+
+type K8sDiscovery struct {
+	ctx    context.Context
+	client *kubernetes.Clientset
+}
+
+func (k *K8sDiscovery) Discover() ([]string, error) {
+	return k.DiscoverInNamespace("")
+}
+func (k *K8sDiscovery) DiscoverInNamespace(namespace string) ([]string, error) {
+	pods, err := k.client.CoreV1().Pods(namespace).List(k.ctx, metav1.ListOptions{
+		LabelSelector: "actor-pool=cart",
+	})
+	if err != nil {
+		return nil, err
+	}
+	hosts := make([]string, 0, len(pods.Items))
+	for _, pod := range pods.Items {
+		hosts = append(hosts, pod.Status.PodIP)
+	}
+	return hosts, nil
+}
+
+type HostChange struct {
+	Host string
+	Type watch.EventType
+}
+
+func (k *K8sDiscovery) Watch() (<-chan HostChange, error) {
+	timeout := int64(30)
+	watcherFn := func(options metav1.ListOptions) (watch.Interface, error) {
+		return k.client.CoreV1().Pods("").Watch(k.ctx, metav1.ListOptions{
+			LabelSelector:  "actor-pool=cart",
+			TimeoutSeconds: &timeout,
+		})
+	}
+	watcher, err := toolsWatch.NewRetryWatcherWithContext(k.ctx, "1", &cache.ListWatch{WatchFunc: watcherFn})
+	if err != nil {
+		return nil, err
+	}
+	ch := make(chan HostChange)
+	go func() {
+		for event := range watcher.ResultChan() {
+
+			pod := event.Object.(*v1.Pod)
+			// log.Printf("pod change %+v", pod.Status.Phase == v1.PodRunning)
+			ch <- HostChange{
+				Host: pod.Status.PodIP,
+				Type: event.Type,
+			}
+		}
+	}()
+	return ch, nil
+}
+
+func NewK8sDiscovery(client *kubernetes.Clientset) *K8sDiscovery {
+	return &K8sDiscovery{
+		ctx:    context.Background(),
+		client: client,
+	}
+}

pkg/discovery/discovery_mock.go

@@ -1,82 +1,12 @@
-package main
+package discovery
 
 import (
 	"context"
 	"sync"
 
-	v1 "k8s.io/api/core/v1"
-	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/watch"
-	"k8s.io/client-go/kubernetes"
-	"k8s.io/client-go/tools/cache"
-	toolsWatch "k8s.io/client-go/tools/watch"
 )
 
-type Discovery interface {
-	Discover() ([]string, error)
-	Watch() (<-chan HostChange, error)
-}
-
-type K8sDiscovery struct {
-	ctx    context.Context
-	client *kubernetes.Clientset
-}
-
-func (k *K8sDiscovery) Discover() ([]string, error) {
-	return k.DiscoverInNamespace("")
-}
-func (k *K8sDiscovery) DiscoverInNamespace(namespace string) ([]string, error) {
-	pods, err := k.client.CoreV1().Pods(namespace).List(k.ctx, metav1.ListOptions{
-		LabelSelector: "actor-pool=cart",
-	})
-	if err != nil {
-		return nil, err
-	}
-	hosts := make([]string, 0, len(pods.Items))
-	for _, pod := range pods.Items {
-		hosts = append(hosts, pod.Status.PodIP)
-	}
-	return hosts, nil
-}
-
-type HostChange struct {
-	Host string
-	Type watch.EventType
-}
-
-func (k *K8sDiscovery) Watch() (<-chan HostChange, error) {
-	timeout := int64(30)
-	watcherFn := func(options metav1.ListOptions) (watch.Interface, error) {
-		return k.client.CoreV1().Pods("").Watch(k.ctx, metav1.ListOptions{
-			LabelSelector:  "actor-pool=cart",
-			TimeoutSeconds: &timeout,
-		})
-	}
-	watcher, err := toolsWatch.NewRetryWatcher("1", &cache.ListWatch{WatchFunc: watcherFn})
-	if err != nil {
-		return nil, err
-	}
-	ch := make(chan HostChange)
-	go func() {
-		for event := range watcher.ResultChan() {
-
-			pod := event.Object.(*v1.Pod)
-			ch <- HostChange{
-				Host: pod.Status.PodIP,
-				Type: event.Type,
-			}
-		}
-	}()
-	return ch, nil
-}
-
-func NewK8sDiscovery(client *kubernetes.Clientset) *K8sDiscovery {
-	return &K8sDiscovery{
-		ctx:    context.Background(),
-		client: client,
-	}
-}
-
 // MockDiscovery is an in-memory Discovery implementation for tests.
 // It allows deterministic injection of host additions/removals without
 // depending on Kubernetes API machinery.

pkg/discovery/discovery_test.go

@@ -1,4 +1,4 @@
-package main
+package discovery
 
 import (
 	"testing"

pkg/discovery/types.go

@@ -0,0 +1,6 @@
+package discovery
+
+type Discovery interface {
+	Discover() ([]string, error)
+	Watch() (<-chan HostChange, error)
+}

pkg/inventory/memory_service.go

@@ -0,0 +1,47 @@
+package inventory
+
+import (
+	"errors"
+	"sync"
+)
+
+type MemoryInventoryService struct {
+	warehouses map[LocationID]*Warehouse
+	mu         sync.RWMutex
+}
+
+func NewMemoryInventoryService() *MemoryInventoryService {
+	return &MemoryInventoryService{
+		warehouses: make(map[LocationID]*Warehouse),
+	}
+}
+
+func (s *MemoryInventoryService) AddWarehouse(warehouse *Warehouse) {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	s.warehouses[warehouse.ID] = warehouse
+}
+
+func (s *MemoryInventoryService) GetInventory(sku SKU, locationID LocationID) (*InventoryItem, error) {
+	s.mu.RLock()
+	defer s.mu.RUnlock()
+
+	warehouse, ok := s.warehouses[locationID]
+	if !ok {
+		return nil, errors.New("warehouse not found")
+	}
+
+	for _, item := range warehouse.Inventory {
+		if item.SKU == sku {
+			return &item, nil
+		}
+	}
+	return nil, errors.New("sku not found in warehouse")
+}
+
+func (s *MemoryInventoryService) ReserveInventory(req ...ReserveRequest) error {
+	// We'll implement the reservation logic using Lua script execution here
+
+	// For now, let's just return an error indicating it's not implemented
+	return errors.New("reservation not implemented yet")
+}

pkg/inventory/redis_service.go

@@ -0,0 +1,251 @@
+package inventory
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"strconv"
+
+	"github.com/redis/go-redis/v9"
+)
+
+type RedisInventoryService struct {
+	client     *redis.Client
+	ctx        context.Context
+	luaScripts map[string]*redis.Script
+}
+
+func NewRedisInventoryService(client *redis.Client, ctx context.Context) (*RedisInventoryService, error) {
+	rdb := client
+
+	// Ping Redis to check connection
+	_, err := rdb.Ping(ctx).Result()
+	if err != nil {
+		return nil, err
+	}
+
+	return &RedisInventoryService{
+		client:     rdb,
+		ctx:        ctx,
+		luaScripts: make(map[string]*redis.Script),
+	}, nil
+}
+
+func (s *RedisInventoryService) LoadLuaScript(key string) error {
+	// Get the script from Redis
+	script, err := s.client.Get(s.ctx, key).Result()
+	if err != nil {
+		return err
+	}
+
+	// Load the script into the luaScripts cache
+	s.luaScripts[key] = redis.NewScript(script)
+	return nil
+}
+
+func (s *RedisInventoryService) AddWarehouse(warehouse *Warehouse) error {
+	// Convert warehouse to Redis-friendly format
+	data := map[string]interface{}{
+		"id":        string(warehouse.ID),
+		"name":      warehouse.Name,
+		"inventory": warehouse.Inventory,
+	}
+
+	// Store in Redis with a key pattern like "warehouse:<ID>"
+	key := "warehouse:" + string(warehouse.ID)
+	_, err := s.client.HMSet(s.ctx, key, data).Result()
+	return err
+}
+
+func (s *RedisInventoryService) GetInventory(sku SKU, locationID LocationID) (int64, error) {
+
+	cmd := s.client.Get(s.ctx, getInventoryKey(sku, locationID))
+	if err := cmd.Err(); err != nil {
+		return 0, err
+	}
+
+	i, err := cmd.Int64()
+	if err != nil {
+		return 0, err
+	}
+
+	return i, nil
+}
+
+func getInventoryKey(sku SKU, locationID LocationID) string {
+	return fmt.Sprintf("inventory:%s:%s", sku, locationID)
+}
+
+func (s *RedisInventoryService) UpdateInventory(rdb redis.Pipeliner, sku SKU, locationID LocationID, quantity int64) error {
+	key := getInventoryKey(sku, locationID)
+	cmd := rdb.Set(s.ctx, key, quantity, 0)
+	return cmd.Err()
+}
+
+var (
+	ErrInsufficientInventory = errors.New("insufficient inventory")
+	ErrInvalidQuantity       = errors.New("invalid quantity")
+	ErrMissingReservation    = errors.New("missing reservation")
+)
+
+func makeKeysAndArgs(req ...ReserveRequest) ([]string, []string) {
+	keys := make([]string, len(req))
+	args := make([]string, len(req))
+	for i, r := range req {
+		if r.Quantity <= 0 {
+			return nil, nil
+		}
+		keys[i] = getInventoryKey(r.SKU, r.LocationID)
+		args[i] = strconv.Itoa(int(r.Quantity))
+	}
+	return keys, args
+}
+
+func (s *RedisInventoryService) ReservationCheck(req ...ReserveRequest) error {
+	if len(req) == 0 {
+		return ErrMissingReservation
+	}
+
+	keys, args := makeKeysAndArgs(req...)
+	if keys == nil || args == nil {
+		return ErrInvalidQuantity
+	}
+
+	cmd := reserveScript.Run(s.ctx, s.client, keys, args)
+	if err := cmd.Err(); err != nil {
+		return err
+	}
+	if val, err := cmd.Int(); err != nil {
+		return err
+	} else if val != 1 {
+		return ErrInsufficientInventory
+	}
+	return nil
+}
+
+func (s *RedisInventoryService) ReserveInventory(req ...ReserveRequest) error {
+	if len(req) == 0 {
+		return ErrMissingReservation
+	}
+
+	keys, args := makeKeysAndArgs(req...)
+	if keys == nil || args == nil {
+		return ErrInvalidQuantity
+	}
+	cmd := reserveScript.Run(s.ctx, s.client, keys, args)
+	if err := cmd.Err(); err != nil {
+		return err
+	}
+	if val, err := cmd.Int(); err != nil {
+		return err
+	} else if val != 1 {
+		return ErrInsufficientInventory
+	}
+	return nil
+}
+
+var reservationCheck = redis.NewScript(`
+-- Get the number of keys passed
+local num_keys = #KEYS
+
+-- Ensure the number of keys matches the number of quantities
+if num_keys ~= #ARGV then
+  return {err = "Script requires the same number of keys and quantities."}
+end
+
+local new_values = {}
+local payload = {}
+
+-- ---
+-- 1. CHECK PHASE
+-- ---
+-- Loop through all keys to check their values first
+for i = 1, num_keys do
+  local key = KEYS[i]
+  local quantity_to_check = tonumber(ARGV[i])
+
+  -- Fail if the quantity is not a valid number
+  if not quantity_to_check then
+    return {err = "Invalid quantity provided for key: " .. key}
+  end
+
+  -- Get the current value stored at the key
+  local current_val = tonumber(redis.call('GET', key))
+
+  -- Check the condition
+  -- Fail if:
+  -- 1. The key doesn't exist (current_val is nil)
+  -- 2. The value is not > the required quantity
+  if not current_val or current_val <= quantity_to_check then
+    -- Return 0 to indicate the operation failed and no changes were made
+    return 0
+  end
+end
+
+return 1
+`)
+
+var reserveScript = redis.NewScript(`
+-- Get the number of keys passed
+local num_keys = #KEYS
+
+-- Ensure the number of keys matches the number of quantities
+if num_keys ~= #ARGV then
+  return {err = "Script requires the same number of keys and quantities."}
+end
+
+local new_values = {}
+local payload = {}
+
+-- ---
+-- 1. CHECK PHASE
+-- ---
+-- Loop through all keys to check their values first
+for i = 1, num_keys do
+  local key = KEYS[i]
+  local quantity_to_check = tonumber(ARGV[i])
+
+  -- Fail if the quantity is not a valid number
+  if not quantity_to_check then
+    return {err = "Invalid quantity provided for key: " .. key}
+  end
+
+  -- Get the current value stored at the key
+  local current_val = tonumber(redis.call('GET', key))
+
+  -- Check the condition
+  -- Fail if:
+  -- 1. The key doesn't exist (current_val is nil)
+  -- 2. The value is not > the required quantity
+  if not current_val or current_val <= quantity_to_check then
+    -- Return 0 to indicate the operation failed and no changes were made
+    return 0
+  end
+
+  -- If the check passes, store the new value
+  local new_val = current_val - quantity_to_check
+  table.insert(new_values, new_val)
+
+  -- Add this key and its *new* value to our payload map
+  payload[key] = new_val
+end
+
+-- ---
+-- 2. UPDATE PHASE
+-- ---
+-- If the script reaches this point, all checks passed.
+-- Now, loop again and apply all the updates.
+for i = 1, num_keys do
+  local key = KEYS[i]
+  local new_val = new_values[i]
+
+  -- Set the key to its new calculated value
+  redis.call('SET', key, new_val)
+end
+local message_payload = cjson.encode(payload)
+
+-- Publish the JSON-encoded message to the specified channel
+redis.call('PUBLISH', "inventory_changed", message_payload)
+-- Return 1 to indicate the operation was successful
+return 1
+`)

pkg/inventory/types.go

@@ -0,0 +1,30 @@
+package inventory
+
+import "time"
+
+type SKU string
+
+type LocationID string
+
+type InventoryItem struct {
+	SKU        SKU
+	Quantity   int
+	LastUpdate time.Time
+}
+
+type Warehouse struct {
+	ID        LocationID
+	Name      string
+	Inventory []InventoryItem
+}
+
+type InventoryService interface {
+	GetInventory(sku SKU, locationID LocationID) (int64, error)
+	ReserveInventory(req ...ReserveRequest) error
+}
+
+type ReserveRequest struct {
+	SKU        SKU
+	LocationID LocationID
+	Quantity   uint32
+}

pkg/messages/control_plane.pb.go

@@ -1,7 +1,7 @@
 // Code generated by protoc-gen-go. DO NOT EDIT.
 // versions:
 // 	protoc-gen-go v1.36.10
-// 	protoc        v3.21.12
+// 	protoc        v6.32.1
 // source: control_plane.proto
 
 package messages
@@ -202,27 +202,27 @@ func (x *NegotiateReply) GetHosts() []string {
 }
 
 // CartIdsReply returns the list of cart IDs (string form) currently owned locally.
-type CartIdsReply struct {
+type ActorIdsReply struct {
 	state         protoimpl.MessageState `protogen:"open.v1"`
-	CartIds       []string               `protobuf:"bytes,1,rep,name=cart_ids,json=cartIds,proto3" json:"cart_ids,omitempty"`
+	Ids           []uint64               `protobuf:"varint,1,rep,packed,name=ids,proto3" json:"ids,omitempty"`
 	unknownFields protoimpl.UnknownFields
 	sizeCache     protoimpl.SizeCache
 }
 
-func (x *CartIdsReply) Reset() {
+func (x *ActorIdsReply) Reset() {
-	*x = CartIdsReply{}
+	*x = ActorIdsReply{}
 	mi := &file_control_plane_proto_msgTypes[4]
 	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 	ms.StoreMessageInfo(mi)
 }
 
-func (x *CartIdsReply) String() string {
+func (x *ActorIdsReply) String() string {
 	return protoimpl.X.MessageStringOf(x)
 }
 
-func (*CartIdsReply) ProtoMessage() {}
+func (*ActorIdsReply) ProtoMessage() {}
 
-func (x *CartIdsReply) ProtoReflect() protoreflect.Message {
+func (x *ActorIdsReply) ProtoReflect() protoreflect.Message {
 	mi := &file_control_plane_proto_msgTypes[4]
 	if x != nil {
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
@@ -234,14 +234,14 @@ func (x *CartIdsReply) ProtoReflect() protoreflect.Message {
 	return mi.MessageOf(x)
 }
 
-// Deprecated: Use CartIdsReply.ProtoReflect.Descriptor instead.
+// Deprecated: Use ActorIdsReply.ProtoReflect.Descriptor instead.
-func (*CartIdsReply) Descriptor() ([]byte, []int) {
+func (*ActorIdsReply) Descriptor() ([]byte, []int) {
 	return file_control_plane_proto_rawDescGZIP(), []int{4}
 }
 
-func (x *CartIdsReply) GetCartIds() []string {
+func (x *ActorIdsReply) GetIds() []uint64 {
 	if x != nil {
-		return x.CartIds
+		return x.Ids
 	}
 	return nil
 }
@@ -344,6 +344,113 @@ func (x *ClosingNotice) GetHost() string {
 	return ""
 }
 
+// OwnershipAnnounce broadcasts first-touch ownership claims for cart IDs.
+// First claim wins; receivers SHOULD NOT overwrite an existing different owner.
+type OwnershipAnnounce struct {
+	state         protoimpl.MessageState `protogen:"open.v1"`
+	Host          string                 `protobuf:"bytes,1,opt,name=host,proto3" json:"host,omitempty"`       // announcing host
+	Ids           []uint64               `protobuf:"varint,2,rep,packed,name=ids,proto3" json:"ids,omitempty"` // newly claimed cart ids
+	unknownFields protoimpl.UnknownFields
+	sizeCache     protoimpl.SizeCache
+}
+
+func (x *OwnershipAnnounce) Reset() {
+	*x = OwnershipAnnounce{}
+	mi := &file_control_plane_proto_msgTypes[7]
+	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
+	ms.StoreMessageInfo(mi)
+}
+
+func (x *OwnershipAnnounce) String() string {
+	return protoimpl.X.MessageStringOf(x)
+}
+
+func (*OwnershipAnnounce) ProtoMessage() {}
+
+func (x *OwnershipAnnounce) ProtoReflect() protoreflect.Message {
+	mi := &file_control_plane_proto_msgTypes[7]
+	if x != nil {
+		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
+		if ms.LoadMessageInfo() == nil {
+			ms.StoreMessageInfo(mi)
+		}
+		return ms
+	}
+	return mi.MessageOf(x)
+}
+
+// Deprecated: Use OwnershipAnnounce.ProtoReflect.Descriptor instead.
+func (*OwnershipAnnounce) Descriptor() ([]byte, []int) {
+	return file_control_plane_proto_rawDescGZIP(), []int{7}
+}
+
+func (x *OwnershipAnnounce) GetHost() string {
+	if x != nil {
+		return x.Host
+	}
+	return ""
+}
+
+func (x *OwnershipAnnounce) GetIds() []uint64 {
+	if x != nil {
+		return x.Ids
+	}
+	return nil
+}
+
+// ExpiryAnnounce broadcasts that a host evicted the provided cart IDs.
+type ExpiryAnnounce struct {
+	state         protoimpl.MessageState `protogen:"open.v1"`
+	Host          string                 `protobuf:"bytes,1,opt,name=host,proto3" json:"host,omitempty"`
+	Ids           []uint64               `protobuf:"varint,2,rep,packed,name=ids,proto3" json:"ids,omitempty"`
+	unknownFields protoimpl.UnknownFields
+	sizeCache     protoimpl.SizeCache
+}
+
+func (x *ExpiryAnnounce) Reset() {
+	*x = ExpiryAnnounce{}
+	mi := &file_control_plane_proto_msgTypes[8]
+	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
+	ms.StoreMessageInfo(mi)
+}
+
+func (x *ExpiryAnnounce) String() string {
+	return protoimpl.X.MessageStringOf(x)
+}
+
+func (*ExpiryAnnounce) ProtoMessage() {}
+
+func (x *ExpiryAnnounce) ProtoReflect() protoreflect.Message {
+	mi := &file_control_plane_proto_msgTypes[8]
+	if x != nil {
+		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
+		if ms.LoadMessageInfo() == nil {
+			ms.StoreMessageInfo(mi)
+		}
+		return ms
+	}
+	return mi.MessageOf(x)
+}
+
+// Deprecated: Use ExpiryAnnounce.ProtoReflect.Descriptor instead.
+func (*ExpiryAnnounce) Descriptor() ([]byte, []int) {
+	return file_control_plane_proto_rawDescGZIP(), []int{8}
+}
+
+func (x *ExpiryAnnounce) GetHost() string {
+	if x != nil {
+		return x.Host
+	}
+	return ""
+}
+
+func (x *ExpiryAnnounce) GetIds() []uint64 {
+	if x != nil {
+		return x.Ids
+	}
+	return nil
+}
+
 var File_control_plane_proto protoreflect.FileDescriptor
 
 const file_control_plane_proto_rawDesc = "" +
@@ -357,19 +464,26 @@ const file_control_plane_proto_rawDesc = "" +
 	"\vknown_hosts\x18\x01 \x03(\tR\n" +
 	"knownHosts\"&\n" +
 	"\x0eNegotiateReply\x12\x14\n" +
-	"\x05hosts\x18\x01 \x03(\tR\x05hosts\")\n" +
+	"\x05hosts\x18\x01 \x03(\tR\x05hosts\"!\n" +
-	"\fCartIdsReply\x12\x19\n" +
+	"\rActorIdsReply\x12\x10\n" +
-	"\bcart_ids\x18\x01 \x03(\tR\acartIds\"F\n" +
+	"\x03ids\x18\x01 \x03(\x04R\x03ids\"F\n" +
 	"\x0eOwnerChangeAck\x12\x1a\n" +
 	"\baccepted\x18\x01 \x01(\bR\baccepted\x12\x18\n" +
 	"\amessage\x18\x02 \x01(\tR\amessage\"#\n" +
 	"\rClosingNotice\x12\x12\n" +
-	"\x04host\x18\x01 \x01(\tR\x04host2\xf4\x01\n" +
+	"\x04host\x18\x01 \x01(\tR\x04host\"9\n" +
+	"\x11OwnershipAnnounce\x12\x12\n" +
+	"\x04host\x18\x01 \x01(\tR\x04host\x12\x10\n" +
+	"\x03ids\x18\x02 \x03(\x04R\x03ids\"6\n" +
+	"\x0eExpiryAnnounce\x12\x12\n" +
+	"\x04host\x18\x01 \x01(\tR\x04host\x12\x10\n" +
+	"\x03ids\x18\x02 \x03(\x04R\x03ids2\x8d\x03\n" +
 	"\fControlPlane\x12,\n" +
 	"\x04Ping\x12\x0f.messages.Empty\x1a\x13.messages.PingReply\x12A\n" +
-	"\tNegotiate\x12\x1a.messages.NegotiateRequest\x1a\x18.messages.NegotiateReply\x125\n" +
+	"\tNegotiate\x12\x1a.messages.NegotiateRequest\x1a\x18.messages.NegotiateReply\x12<\n" +
-	"\n" +
+	"\x10GetLocalActorIds\x12\x0f.messages.Empty\x1a\x17.messages.ActorIdsReply\x12J\n" +
-	"GetCartIds\x12\x0f.messages.Empty\x1a\x16.messages.CartIdsReply\x12<\n" +
+	"\x11AnnounceOwnership\x12\x1b.messages.OwnershipAnnounce\x1a\x18.messages.OwnerChangeAck\x12D\n" +
+	"\x0eAnnounceExpiry\x12\x18.messages.ExpiryAnnounce\x1a\x18.messages.OwnerChangeAck\x12<\n" +
 	"\aClosing\x12\x17.messages.ClosingNotice\x1a\x18.messages.OwnerChangeAckB.Z,git.tornberg.me/go-cart-actor/proto;messagesb\x06proto3"
 
 var (
@@ -384,27 +498,33 @@ func file_control_plane_proto_rawDescGZIP() []byte {
 	return file_control_plane_proto_rawDescData
 }
 
-var file_control_plane_proto_msgTypes = make([]protoimpl.MessageInfo, 7)
+var file_control_plane_proto_msgTypes = make([]protoimpl.MessageInfo, 9)
 var file_control_plane_proto_goTypes = []any{
 	(*Empty)(nil),             // 0: messages.Empty
 	(*PingReply)(nil),         // 1: messages.PingReply
 	(*NegotiateRequest)(nil),  // 2: messages.NegotiateRequest
 	(*NegotiateReply)(nil),    // 3: messages.NegotiateReply
-	(*CartIdsReply)(nil),     // 4: messages.CartIdsReply
+	(*ActorIdsReply)(nil),     // 4: messages.ActorIdsReply
 	(*OwnerChangeAck)(nil),    // 5: messages.OwnerChangeAck
 	(*ClosingNotice)(nil),     // 6: messages.ClosingNotice
+	(*OwnershipAnnounce)(nil), // 7: messages.OwnershipAnnounce
+	(*ExpiryAnnounce)(nil),    // 8: messages.ExpiryAnnounce
 }
 var file_control_plane_proto_depIdxs = []int32{
 	0, // 0: messages.ControlPlane.Ping:input_type -> messages.Empty
 	2, // 1: messages.ControlPlane.Negotiate:input_type -> messages.NegotiateRequest
-	0, // 2: messages.ControlPlane.GetCartIds:input_type -> messages.Empty
+	0, // 2: messages.ControlPlane.GetLocalActorIds:input_type -> messages.Empty
-	6, // 3: messages.ControlPlane.Closing:input_type -> messages.ClosingNotice
+	7, // 3: messages.ControlPlane.AnnounceOwnership:input_type -> messages.OwnershipAnnounce
-	1, // 4: messages.ControlPlane.Ping:output_type -> messages.PingReply
+	8, // 4: messages.ControlPlane.AnnounceExpiry:input_type -> messages.ExpiryAnnounce
-	3, // 5: messages.ControlPlane.Negotiate:output_type -> messages.NegotiateReply
+	6, // 5: messages.ControlPlane.Closing:input_type -> messages.ClosingNotice
-	4, // 6: messages.ControlPlane.GetCartIds:output_type -> messages.CartIdsReply
+	1, // 6: messages.ControlPlane.Ping:output_type -> messages.PingReply
-	5, // 7: messages.ControlPlane.Closing:output_type -> messages.OwnerChangeAck
+	3, // 7: messages.ControlPlane.Negotiate:output_type -> messages.NegotiateReply
-	4, // [4:8] is the sub-list for method output_type
+	4, // 8: messages.ControlPlane.GetLocalActorIds:output_type -> messages.ActorIdsReply
-	0, // [0:4] is the sub-list for method input_type
+	5, // 9: messages.ControlPlane.AnnounceOwnership:output_type -> messages.OwnerChangeAck
+	5, // 10: messages.ControlPlane.AnnounceExpiry:output_type -> messages.OwnerChangeAck
+	5, // 11: messages.ControlPlane.Closing:output_type -> messages.OwnerChangeAck
+	6, // [6:12] is the sub-list for method output_type
+	0, // [0:6] is the sub-list for method input_type
 	0, // [0:0] is the sub-list for extension type_name
 	0, // [0:0] is the sub-list for extension extendee
 	0, // [0:0] is the sub-list for field type_name
@@ -421,7 +541,7 @@ func file_control_plane_proto_init() {
 			GoPackagePath: reflect.TypeOf(x{}).PkgPath(),
 			RawDescriptor: unsafe.Slice(unsafe.StringData(file_control_plane_proto_rawDesc), len(file_control_plane_proto_rawDesc)),
 			NumEnums:      0,
-			NumMessages:   7,
+			NumMessages:   9,
 			NumExtensions: 0,
 			NumServices:   1,
 		},

pkg/messages/control_plane_grpc.pb.go

@@ -1,7 +1,7 @@
 // Code generated by protoc-gen-go-grpc. DO NOT EDIT.
 // versions:
 // - protoc-gen-go-grpc v1.5.1
-// - protoc             v3.21.12
+// - protoc             v6.32.1
 // source: control_plane.proto
 
 package messages
@@ -21,7 +21,9 @@ const _ = grpc.SupportPackageIsVersion9
 const (
 	ControlPlane_Ping_FullMethodName              = "/messages.ControlPlane/Ping"
 	ControlPlane_Negotiate_FullMethodName         = "/messages.ControlPlane/Negotiate"
-	ControlPlane_GetCartIds_FullMethodName = "/messages.ControlPlane/GetCartIds"
+	ControlPlane_GetLocalActorIds_FullMethodName  = "/messages.ControlPlane/GetLocalActorIds"
+	ControlPlane_AnnounceOwnership_FullMethodName = "/messages.ControlPlane/AnnounceOwnership"
+	ControlPlane_AnnounceExpiry_FullMethodName    = "/messages.ControlPlane/AnnounceExpiry"
 	ControlPlane_Closing_FullMethodName           = "/messages.ControlPlane/Closing"
 )
 
@@ -36,7 +38,11 @@ type ControlPlaneClient interface {
 	// Negotiate merges host views; used during discovery & convergence.
 	Negotiate(ctx context.Context, in *NegotiateRequest, opts ...grpc.CallOption) (*NegotiateReply, error)
 	// GetCartIds lists currently owned cart IDs on this node.
-	GetCartIds(ctx context.Context, in *Empty, opts ...grpc.CallOption) (*CartIdsReply, error)
+	GetLocalActorIds(ctx context.Context, in *Empty, opts ...grpc.CallOption) (*ActorIdsReply, error)
+	// Ownership announcement: first-touch claim broadcast (idempotent; best-effort).
+	AnnounceOwnership(ctx context.Context, in *OwnershipAnnounce, opts ...grpc.CallOption) (*OwnerChangeAck, error)
+	// Expiry announcement: drop remote ownership hints when local TTL expires.
+	AnnounceExpiry(ctx context.Context, in *ExpiryAnnounce, opts ...grpc.CallOption) (*OwnerChangeAck, error)
 	// Closing announces graceful shutdown so peers can proactively adjust.
 	Closing(ctx context.Context, in *ClosingNotice, opts ...grpc.CallOption) (*OwnerChangeAck, error)
 }
@@ -69,10 +75,30 @@ func (c *controlPlaneClient) Negotiate(ctx context.Context, in *NegotiateRequest
 	return out, nil
 }
 
-func (c *controlPlaneClient) GetCartIds(ctx context.Context, in *Empty, opts ...grpc.CallOption) (*CartIdsReply, error) {
+func (c *controlPlaneClient) GetLocalActorIds(ctx context.Context, in *Empty, opts ...grpc.CallOption) (*ActorIdsReply, error) {
 	cOpts := append([]grpc.CallOption{grpc.StaticMethod()}, opts...)
-	out := new(CartIdsReply)
+	out := new(ActorIdsReply)
-	err := c.cc.Invoke(ctx, ControlPlane_GetCartIds_FullMethodName, in, out, cOpts...)
+	err := c.cc.Invoke(ctx, ControlPlane_GetLocalActorIds_FullMethodName, in, out, cOpts...)
+	if err != nil {
+		return nil, err
+	}
+	return out, nil
+}
+
+func (c *controlPlaneClient) AnnounceOwnership(ctx context.Context, in *OwnershipAnnounce, opts ...grpc.CallOption) (*OwnerChangeAck, error) {
+	cOpts := append([]grpc.CallOption{grpc.StaticMethod()}, opts...)
+	out := new(OwnerChangeAck)
+	err := c.cc.Invoke(ctx, ControlPlane_AnnounceOwnership_FullMethodName, in, out, cOpts...)
+	if err != nil {
+		return nil, err
+	}
+	return out, nil
+}
+
+func (c *controlPlaneClient) AnnounceExpiry(ctx context.Context, in *ExpiryAnnounce, opts ...grpc.CallOption) (*OwnerChangeAck, error) {
+	cOpts := append([]grpc.CallOption{grpc.StaticMethod()}, opts...)
+	out := new(OwnerChangeAck)
+	err := c.cc.Invoke(ctx, ControlPlane_AnnounceExpiry_FullMethodName, in, out, cOpts...)
 	if err != nil {
 		return nil, err
 	}
@@ -100,7 +126,11 @@ type ControlPlaneServer interface {
 	// Negotiate merges host views; used during discovery & convergence.
 	Negotiate(context.Context, *NegotiateRequest) (*NegotiateReply, error)
 	// GetCartIds lists currently owned cart IDs on this node.
-	GetCartIds(context.Context, *Empty) (*CartIdsReply, error)
+	GetLocalActorIds(context.Context, *Empty) (*ActorIdsReply, error)
+	// Ownership announcement: first-touch claim broadcast (idempotent; best-effort).
+	AnnounceOwnership(context.Context, *OwnershipAnnounce) (*OwnerChangeAck, error)
+	// Expiry announcement: drop remote ownership hints when local TTL expires.
+	AnnounceExpiry(context.Context, *ExpiryAnnounce) (*OwnerChangeAck, error)
 	// Closing announces graceful shutdown so peers can proactively adjust.
 	Closing(context.Context, *ClosingNotice) (*OwnerChangeAck, error)
 	mustEmbedUnimplementedControlPlaneServer()
@@ -119,8 +149,14 @@ func (UnimplementedControlPlaneServer) Ping(context.Context, *Empty) (*PingReply
 func (UnimplementedControlPlaneServer) Negotiate(context.Context, *NegotiateRequest) (*NegotiateReply, error) {
 	return nil, status.Errorf(codes.Unimplemented, "method Negotiate not implemented")
 }
-func (UnimplementedControlPlaneServer) GetCartIds(context.Context, *Empty) (*CartIdsReply, error) {
+func (UnimplementedControlPlaneServer) GetLocalActorIds(context.Context, *Empty) (*ActorIdsReply, error) {
-	return nil, status.Errorf(codes.Unimplemented, "method GetCartIds not implemented")
+	return nil, status.Errorf(codes.Unimplemented, "method GetLocalActorIds not implemented")
+}
+func (UnimplementedControlPlaneServer) AnnounceOwnership(context.Context, *OwnershipAnnounce) (*OwnerChangeAck, error) {
+	return nil, status.Errorf(codes.Unimplemented, "method AnnounceOwnership not implemented")
+}
+func (UnimplementedControlPlaneServer) AnnounceExpiry(context.Context, *ExpiryAnnounce) (*OwnerChangeAck, error) {
+	return nil, status.Errorf(codes.Unimplemented, "method AnnounceExpiry not implemented")
 }
 func (UnimplementedControlPlaneServer) Closing(context.Context, *ClosingNotice) (*OwnerChangeAck, error) {
 	return nil, status.Errorf(codes.Unimplemented, "method Closing not implemented")
@@ -182,20 +218,56 @@ func _ControlPlane_Negotiate_Handler(srv interface{}, ctx context.Context, dec f
 	return interceptor(ctx, in, info, handler)
 }
 
-func _ControlPlane_GetCartIds_Handler(srv interface{}, ctx context.Context, dec func(interface{}) error, interceptor grpc.UnaryServerInterceptor) (interface{}, error) {
+func _ControlPlane_GetLocalActorIds_Handler(srv interface{}, ctx context.Context, dec func(interface{}) error, interceptor grpc.UnaryServerInterceptor) (interface{}, error) {
 	in := new(Empty)
 	if err := dec(in); err != nil {
 		return nil, err
 	}
 	if interceptor == nil {
-		return srv.(ControlPlaneServer).GetCartIds(ctx, in)
+		return srv.(ControlPlaneServer).GetLocalActorIds(ctx, in)
 	}
 	info := &grpc.UnaryServerInfo{
 		Server:     srv,
-		FullMethod: ControlPlane_GetCartIds_FullMethodName,
+		FullMethod: ControlPlane_GetLocalActorIds_FullMethodName,
 	}
 	handler := func(ctx context.Context, req interface{}) (interface{}, error) {
-		return srv.(ControlPlaneServer).GetCartIds(ctx, req.(*Empty))
+		return srv.(ControlPlaneServer).GetLocalActorIds(ctx, req.(*Empty))
+	}
+	return interceptor(ctx, in, info, handler)
+}
+
+func _ControlPlane_AnnounceOwnership_Handler(srv interface{}, ctx context.Context, dec func(interface{}) error, interceptor grpc.UnaryServerInterceptor) (interface{}, error) {
+	in := new(OwnershipAnnounce)
+	if err := dec(in); err != nil {
+		return nil, err
+	}
+	if interceptor == nil {
+		return srv.(ControlPlaneServer).AnnounceOwnership(ctx, in)
+	}
+	info := &grpc.UnaryServerInfo{
+		Server:     srv,
+		FullMethod: ControlPlane_AnnounceOwnership_FullMethodName,
+	}
+	handler := func(ctx context.Context, req interface{}) (interface{}, error) {
+		return srv.(ControlPlaneServer).AnnounceOwnership(ctx, req.(*OwnershipAnnounce))
+	}
+	return interceptor(ctx, in, info, handler)
+}
+
+func _ControlPlane_AnnounceExpiry_Handler(srv interface{}, ctx context.Context, dec func(interface{}) error, interceptor grpc.UnaryServerInterceptor) (interface{}, error) {
+	in := new(ExpiryAnnounce)
+	if err := dec(in); err != nil {
+		return nil, err
+	}
+	if interceptor == nil {
+		return srv.(ControlPlaneServer).AnnounceExpiry(ctx, in)
+	}
+	info := &grpc.UnaryServerInfo{
+		Server:     srv,
+		FullMethod: ControlPlane_AnnounceExpiry_FullMethodName,
+	}
+	handler := func(ctx context.Context, req interface{}) (interface{}, error) {
+		return srv.(ControlPlaneServer).AnnounceExpiry(ctx, req.(*ExpiryAnnounce))
 	}
 	return interceptor(ctx, in, info, handler)
 }
@@ -234,8 +306,16 @@ var ControlPlane_ServiceDesc = grpc.ServiceDesc{
 			Handler:    _ControlPlane_Negotiate_Handler,
 		},
 		{
-			MethodName: "GetCartIds",
+			MethodName: "GetLocalActorIds",
-			Handler:    _ControlPlane_GetCartIds_Handler,
+			Handler:    _ControlPlane_GetLocalActorIds_Handler,
+		},
+		{
+			MethodName: "AnnounceOwnership",
+			Handler:    _ControlPlane_AnnounceOwnership_Handler,
+		},
+		{
+			MethodName: "AnnounceExpiry",
+			Handler:    _ControlPlane_AnnounceExpiry_Handler,
 		},
 		{
 			MethodName: "Closing",

pkg/messages/messages.pb.go

@@ -1,7 +1,7 @@
 // Code generated by protoc-gen-go. DO NOT EDIT.
 // versions:
 // 	protoc-gen-go v1.36.10
-// 	protoc        v3.21.12
+// 	protoc        v6.32.1
 // source: messages.proto
 
 package messages
@@ -9,6 +9,7 @@ package messages
 import (
 	protoreflect "google.golang.org/protobuf/reflect/protoreflect"
 	protoimpl "google.golang.org/protobuf/runtime/protoimpl"
+	anypb "google.golang.org/protobuf/types/known/anypb"
 	reflect "reflect"
 	sync "sync"
 	unsafe "unsafe"
@@ -21,30 +22,26 @@ const (
 	_ = protoimpl.EnforceVersion(protoimpl.MaxVersion - 20)
 )
 
-type AddRequest struct {
+type ClearCartRequest struct {
 	state         protoimpl.MessageState `protogen:"open.v1"`
-	Quantity      int32                  `protobuf:"varint,1,opt,name=quantity,proto3" json:"quantity,omitempty"`
-	Sku           string                 `protobuf:"bytes,2,opt,name=sku,proto3" json:"sku,omitempty"`
-	Country       string                 `protobuf:"bytes,3,opt,name=country,proto3" json:"country,omitempty"`
-	StoreId       *string                `protobuf:"bytes,4,opt,name=storeId,proto3,oneof" json:"storeId,omitempty"`
 	unknownFields protoimpl.UnknownFields
 	sizeCache     protoimpl.SizeCache
 }
 
-func (x *AddRequest) Reset() {
+func (x *ClearCartRequest) Reset() {
-	*x = AddRequest{}
+	*x = ClearCartRequest{}
 	mi := &file_messages_proto_msgTypes[0]
 	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 	ms.StoreMessageInfo(mi)
 }
 
-func (x *AddRequest) String() string {
+func (x *ClearCartRequest) String() string {
 	return protoimpl.X.MessageStringOf(x)
 }
 
-func (*AddRequest) ProtoMessage() {}
+func (*ClearCartRequest) ProtoMessage() {}
 
-func (x *AddRequest) ProtoReflect() protoreflect.Message {
+func (x *ClearCartRequest) ProtoReflect() protoreflect.Message {
 	mi := &file_messages_proto_msgTypes[0]
 	if x != nil {
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
@@ -56,86 +53,14 @@ func (x *AddRequest) ProtoReflect() protoreflect.Message {
 	return mi.MessageOf(x)
 }
 
-// Deprecated: Use AddRequest.ProtoReflect.Descriptor instead.
+// Deprecated: Use ClearCartRequest.ProtoReflect.Descriptor instead.
-func (*AddRequest) Descriptor() ([]byte, []int) {
+func (*ClearCartRequest) Descriptor() ([]byte, []int) {
 	return file_messages_proto_rawDescGZIP(), []int{0}
 }
 
-func (x *AddRequest) GetQuantity() int32 {
-	if x != nil {
-		return x.Quantity
-	}
-	return 0
-}
-
-func (x *AddRequest) GetSku() string {
-	if x != nil {
-		return x.Sku
-	}
-	return ""
-}
-
-func (x *AddRequest) GetCountry() string {
-	if x != nil {
-		return x.Country
-	}
-	return ""
-}
-
-func (x *AddRequest) GetStoreId() string {
-	if x != nil && x.StoreId != nil {
-		return *x.StoreId
-	}
-	return ""
-}
-
-type SetCartRequest struct {
-	state         protoimpl.MessageState `protogen:"open.v1"`
-	Items         []*AddRequest          `protobuf:"bytes,1,rep,name=items,proto3" json:"items,omitempty"`
-	unknownFields protoimpl.UnknownFields
-	sizeCache     protoimpl.SizeCache
-}
-
-func (x *SetCartRequest) Reset() {
-	*x = SetCartRequest{}
-	mi := &file_messages_proto_msgTypes[1]
-	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
-	ms.StoreMessageInfo(mi)
-}
-
-func (x *SetCartRequest) String() string {
-	return protoimpl.X.MessageStringOf(x)
-}
-
-func (*SetCartRequest) ProtoMessage() {}
-
-func (x *SetCartRequest) ProtoReflect() protoreflect.Message {
-	mi := &file_messages_proto_msgTypes[1]
-	if x != nil {
-		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
-		if ms.LoadMessageInfo() == nil {
-			ms.StoreMessageInfo(mi)
-		}
-		return ms
-	}
-	return mi.MessageOf(x)
-}
-
-// Deprecated: Use SetCartRequest.ProtoReflect.Descriptor instead.
-func (*SetCartRequest) Descriptor() ([]byte, []int) {
-	return file_messages_proto_rawDescGZIP(), []int{1}
-}
-
-func (x *SetCartRequest) GetItems() []*AddRequest {
-	if x != nil {
-		return x.Items
-	}
-	return nil
-}
-
 type AddItem struct {
 	state         protoimpl.MessageState `protogen:"open.v1"`
-	ItemId        int64                  `protobuf:"varint,1,opt,name=item_id,json=itemId,proto3" json:"item_id,omitempty"`
+	ItemId        uint32                 `protobuf:"varint,1,opt,name=item_id,json=itemId,proto3" json:"item_id,omitempty"`
 	Quantity      int32                  `protobuf:"varint,2,opt,name=quantity,proto3" json:"quantity,omitempty"`
 	Price         int64                  `protobuf:"varint,3,opt,name=price,proto3" json:"price,omitempty"`
 	OrgPrice      int64                  `protobuf:"varint,9,opt,name=orgPrice,proto3" json:"orgPrice,omitempty"`
@@ -155,15 +80,17 @@ type AddItem struct {
 	SellerId      string                 `protobuf:"bytes,19,opt,name=sellerId,proto3" json:"sellerId,omitempty"`
 	SellerName    string                 `protobuf:"bytes,20,opt,name=sellerName,proto3" json:"sellerName,omitempty"`
 	Country       string                 `protobuf:"bytes,21,opt,name=country,proto3" json:"country,omitempty"`
+	SaleStatus    string                 `protobuf:"bytes,24,opt,name=saleStatus,proto3" json:"saleStatus,omitempty"`
 	Outlet        *string                `protobuf:"bytes,12,opt,name=outlet,proto3,oneof" json:"outlet,omitempty"`
 	StoreId       *string                `protobuf:"bytes,22,opt,name=storeId,proto3,oneof" json:"storeId,omitempty"`
+	ParentId      *uint32                `protobuf:"varint,23,opt,name=parentId,proto3,oneof" json:"parentId,omitempty"`
 	unknownFields protoimpl.UnknownFields
 	sizeCache     protoimpl.SizeCache
 }
 
 func (x *AddItem) Reset() {
 	*x = AddItem{}
-	mi := &file_messages_proto_msgTypes[2]
+	mi := &file_messages_proto_msgTypes[1]
 	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 	ms.StoreMessageInfo(mi)
 }
@@ -175,7 +102,7 @@ func (x *AddItem) String() string {
 func (*AddItem) ProtoMessage() {}
 
 func (x *AddItem) ProtoReflect() protoreflect.Message {
-	mi := &file_messages_proto_msgTypes[2]
+	mi := &file_messages_proto_msgTypes[1]
 	if x != nil {
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		if ms.LoadMessageInfo() == nil {
@@ -188,10 +115,10 @@ func (x *AddItem) ProtoReflect() protoreflect.Message {
 
 // Deprecated: Use AddItem.ProtoReflect.Descriptor instead.
 func (*AddItem) Descriptor() ([]byte, []int) {
-	return file_messages_proto_rawDescGZIP(), []int{2}
+	return file_messages_proto_rawDescGZIP(), []int{1}
 }
 
-func (x *AddItem) GetItemId() int64 {
+func (x *AddItem) GetItemId() uint32 {
 	if x != nil {
 		return x.ItemId
 	}
@@ -331,6 +258,13 @@ func (x *AddItem) GetCountry() string {
 	return ""
 }
 
+func (x *AddItem) GetSaleStatus() string {
+	if x != nil {
+		return x.SaleStatus
+	}
+	return ""
+}
+
 func (x *AddItem) GetOutlet() string {
 	if x != nil && x.Outlet != nil {
 		return *x.Outlet
@@ -345,16 +279,23 @@ func (x *AddItem) GetStoreId() string {
 	return ""
 }
 
+func (x *AddItem) GetParentId() uint32 {
+	if x != nil && x.ParentId != nil {
+		return *x.ParentId
+	}
+	return 0
+}
+
 type RemoveItem struct {
 	state         protoimpl.MessageState `protogen:"open.v1"`
-	Id            int64                  `protobuf:"varint,1,opt,name=Id,proto3" json:"Id,omitempty"`
+	Id            uint32                 `protobuf:"varint,1,opt,name=Id,proto3" json:"Id,omitempty"`
 	unknownFields protoimpl.UnknownFields
 	sizeCache     protoimpl.SizeCache
 }
 
 func (x *RemoveItem) Reset() {
 	*x = RemoveItem{}
-	mi := &file_messages_proto_msgTypes[3]
+	mi := &file_messages_proto_msgTypes[2]
 	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 	ms.StoreMessageInfo(mi)
 }
@@ -366,7 +307,7 @@ func (x *RemoveItem) String() string {
 func (*RemoveItem) ProtoMessage() {}
 
 func (x *RemoveItem) ProtoReflect() protoreflect.Message {
-	mi := &file_messages_proto_msgTypes[3]
+	mi := &file_messages_proto_msgTypes[2]
 	if x != nil {
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		if ms.LoadMessageInfo() == nil {
@@ -379,10 +320,10 @@ func (x *RemoveItem) ProtoReflect() protoreflect.Message {
 
 // Deprecated: Use RemoveItem.ProtoReflect.Descriptor instead.
 func (*RemoveItem) Descriptor() ([]byte, []int) {
-	return file_messages_proto_rawDescGZIP(), []int{3}
+	return file_messages_proto_rawDescGZIP(), []int{2}
 }
 
-func (x *RemoveItem) GetId() int64 {
+func (x *RemoveItem) GetId() uint32 {
 	if x != nil {
 		return x.Id
 	}
@@ -391,7 +332,7 @@ func (x *RemoveItem) GetId() int64 {
 
 type ChangeQuantity struct {
 	state         protoimpl.MessageState `protogen:"open.v1"`
-	Id            int64                  `protobuf:"varint,1,opt,name=id,proto3" json:"id,omitempty"`
+	Id            uint32                 `protobuf:"varint,1,opt,name=Id,proto3" json:"Id,omitempty"`
 	Quantity      int32                  `protobuf:"varint,2,opt,name=quantity,proto3" json:"quantity,omitempty"`
 	unknownFields protoimpl.UnknownFields
 	sizeCache     protoimpl.SizeCache
@@ -399,7 +340,7 @@ type ChangeQuantity struct {
 
 func (x *ChangeQuantity) Reset() {
 	*x = ChangeQuantity{}
-	mi := &file_messages_proto_msgTypes[4]
+	mi := &file_messages_proto_msgTypes[3]
 	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 	ms.StoreMessageInfo(mi)
 }
@@ -411,7 +352,7 @@ func (x *ChangeQuantity) String() string {
 func (*ChangeQuantity) ProtoMessage() {}
 
 func (x *ChangeQuantity) ProtoReflect() protoreflect.Message {
-	mi := &file_messages_proto_msgTypes[4]
+	mi := &file_messages_proto_msgTypes[3]
 	if x != nil {
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		if ms.LoadMessageInfo() == nil {
@@ -424,10 +365,10 @@ func (x *ChangeQuantity) ProtoReflect() protoreflect.Message {
 
 // Deprecated: Use ChangeQuantity.ProtoReflect.Descriptor instead.
 func (*ChangeQuantity) Descriptor() ([]byte, []int) {
-	return file_messages_proto_rawDescGZIP(), []int{4}
+	return file_messages_proto_rawDescGZIP(), []int{3}
 }
 
-func (x *ChangeQuantity) GetId() int64 {
+func (x *ChangeQuantity) GetId() uint32 {
 	if x != nil {
 		return x.Id
 	}
@@ -444,7 +385,7 @@ func (x *ChangeQuantity) GetQuantity() int32 {
 type SetDelivery struct {
 	state         protoimpl.MessageState `protogen:"open.v1"`
 	Provider      string                 `protobuf:"bytes,1,opt,name=provider,proto3" json:"provider,omitempty"`
-	Items         []int64                `protobuf:"varint,2,rep,packed,name=items,proto3" json:"items,omitempty"`
+	Items         []uint32               `protobuf:"varint,2,rep,packed,name=items,proto3" json:"items,omitempty"`
 	PickupPoint   *PickupPoint           `protobuf:"bytes,3,opt,name=pickupPoint,proto3,oneof" json:"pickupPoint,omitempty"`
 	Country       string                 `protobuf:"bytes,4,opt,name=country,proto3" json:"country,omitempty"`
 	Zip           string                 `protobuf:"bytes,5,opt,name=zip,proto3" json:"zip,omitempty"`
@@ -456,7 +397,7 @@ type SetDelivery struct {
 
 func (x *SetDelivery) Reset() {
 	*x = SetDelivery{}
-	mi := &file_messages_proto_msgTypes[5]
+	mi := &file_messages_proto_msgTypes[4]
 	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 	ms.StoreMessageInfo(mi)
 }
@@ -468,7 +409,7 @@ func (x *SetDelivery) String() string {
 func (*SetDelivery) ProtoMessage() {}
 
 func (x *SetDelivery) ProtoReflect() protoreflect.Message {
-	mi := &file_messages_proto_msgTypes[5]
+	mi := &file_messages_proto_msgTypes[4]
 	if x != nil {
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		if ms.LoadMessageInfo() == nil {
@@ -481,7 +422,7 @@ func (x *SetDelivery) ProtoReflect() protoreflect.Message {
 
 // Deprecated: Use SetDelivery.ProtoReflect.Descriptor instead.
 func (*SetDelivery) Descriptor() ([]byte, []int) {
-	return file_messages_proto_rawDescGZIP(), []int{5}
+	return file_messages_proto_rawDescGZIP(), []int{4}
 }
 
 func (x *SetDelivery) GetProvider() string {
@@ -491,7 +432,7 @@ func (x *SetDelivery) GetProvider() string {
 	return ""
 }
 
-func (x *SetDelivery) GetItems() []int64 {
+func (x *SetDelivery) GetItems() []uint32 {
 	if x != nil {
 		return x.Items
 	}
@@ -535,7 +476,7 @@ func (x *SetDelivery) GetCity() string {
 
 type SetPickupPoint struct {
 	state         protoimpl.MessageState `protogen:"open.v1"`
-	DeliveryId    int64                  `protobuf:"varint,1,opt,name=deliveryId,proto3" json:"deliveryId,omitempty"`
+	DeliveryId    uint32                 `protobuf:"varint,1,opt,name=deliveryId,proto3" json:"deliveryId,omitempty"`
 	Id            string                 `protobuf:"bytes,2,opt,name=id,proto3" json:"id,omitempty"`
 	Name          *string                `protobuf:"bytes,3,opt,name=name,proto3,oneof" json:"name,omitempty"`
 	Address       *string                `protobuf:"bytes,4,opt,name=address,proto3,oneof" json:"address,omitempty"`
@@ -548,7 +489,7 @@ type SetPickupPoint struct {
 
 func (x *SetPickupPoint) Reset() {
 	*x = SetPickupPoint{}
-	mi := &file_messages_proto_msgTypes[6]
+	mi := &file_messages_proto_msgTypes[5]
 	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 	ms.StoreMessageInfo(mi)
 }
@@ -560,7 +501,7 @@ func (x *SetPickupPoint) String() string {
 func (*SetPickupPoint) ProtoMessage() {}
 
 func (x *SetPickupPoint) ProtoReflect() protoreflect.Message {
-	mi := &file_messages_proto_msgTypes[6]
+	mi := &file_messages_proto_msgTypes[5]
 	if x != nil {
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		if ms.LoadMessageInfo() == nil {
@@ -573,10 +514,10 @@ func (x *SetPickupPoint) ProtoReflect() protoreflect.Message {
 
 // Deprecated: Use SetPickupPoint.ProtoReflect.Descriptor instead.
 func (*SetPickupPoint) Descriptor() ([]byte, []int) {
-	return file_messages_proto_rawDescGZIP(), []int{6}
+	return file_messages_proto_rawDescGZIP(), []int{5}
 }
 
-func (x *SetPickupPoint) GetDeliveryId() int64 {
+func (x *SetPickupPoint) GetDeliveryId() uint32 {
 	if x != nil {
 		return x.DeliveryId
 	}
@@ -639,7 +580,7 @@ type PickupPoint struct {
 
 func (x *PickupPoint) Reset() {
 	*x = PickupPoint{}
-	mi := &file_messages_proto_msgTypes[7]
+	mi := &file_messages_proto_msgTypes[6]
 	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 	ms.StoreMessageInfo(mi)
 }
@@ -651,7 +592,7 @@ func (x *PickupPoint) String() string {
 func (*PickupPoint) ProtoMessage() {}
 
 func (x *PickupPoint) ProtoReflect() protoreflect.Message {
-	mi := &file_messages_proto_msgTypes[7]
+	mi := &file_messages_proto_msgTypes[6]
 	if x != nil {
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		if ms.LoadMessageInfo() == nil {
@@ -664,7 +605,7 @@ func (x *PickupPoint) ProtoReflect() protoreflect.Message {
 
 // Deprecated: Use PickupPoint.ProtoReflect.Descriptor instead.
 func (*PickupPoint) Descriptor() ([]byte, []int) {
-	return file_messages_proto_rawDescGZIP(), []int{7}
+	return file_messages_proto_rawDescGZIP(), []int{6}
 }
 
 func (x *PickupPoint) GetId() string {
@@ -711,14 +652,14 @@ func (x *PickupPoint) GetCountry() string {
 
 type RemoveDelivery struct {
 	state         protoimpl.MessageState `protogen:"open.v1"`
-	Id            int64                  `protobuf:"varint,1,opt,name=id,proto3" json:"id,omitempty"`
+	Id            uint32                 `protobuf:"varint,1,opt,name=id,proto3" json:"id,omitempty"`
 	unknownFields protoimpl.UnknownFields
 	sizeCache     protoimpl.SizeCache
 }
 
 func (x *RemoveDelivery) Reset() {
 	*x = RemoveDelivery{}
-	mi := &file_messages_proto_msgTypes[8]
+	mi := &file_messages_proto_msgTypes[7]
 	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 	ms.StoreMessageInfo(mi)
 }
@@ -730,7 +671,7 @@ func (x *RemoveDelivery) String() string {
 func (*RemoveDelivery) ProtoMessage() {}
 
 func (x *RemoveDelivery) ProtoReflect() protoreflect.Message {
-	mi := &file_messages_proto_msgTypes[8]
+	mi := &file_messages_proto_msgTypes[7]
 	if x != nil {
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		if ms.LoadMessageInfo() == nil {
@@ -743,10 +684,10 @@ func (x *RemoveDelivery) ProtoReflect() protoreflect.Message {
 
 // Deprecated: Use RemoveDelivery.ProtoReflect.Descriptor instead.
 func (*RemoveDelivery) Descriptor() ([]byte, []int) {
-	return file_messages_proto_rawDescGZIP(), []int{8}
+	return file_messages_proto_rawDescGZIP(), []int{7}
 }
 
-func (x *RemoveDelivery) GetId() int64 {
+func (x *RemoveDelivery) GetId() uint32 {
 	if x != nil {
 		return x.Id
 	}
@@ -767,7 +708,7 @@ type CreateCheckoutOrder struct {
 
 func (x *CreateCheckoutOrder) Reset() {
 	*x = CreateCheckoutOrder{}
-	mi := &file_messages_proto_msgTypes[9]
+	mi := &file_messages_proto_msgTypes[8]
 	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 	ms.StoreMessageInfo(mi)
 }
@@ -779,7 +720,7 @@ func (x *CreateCheckoutOrder) String() string {
 func (*CreateCheckoutOrder) ProtoMessage() {}
 
 func (x *CreateCheckoutOrder) ProtoReflect() protoreflect.Message {
-	mi := &file_messages_proto_msgTypes[9]
+	mi := &file_messages_proto_msgTypes[8]
 	if x != nil {
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		if ms.LoadMessageInfo() == nil {
@@ -792,7 +733,7 @@ func (x *CreateCheckoutOrder) ProtoReflect() protoreflect.Message {
 
 // Deprecated: Use CreateCheckoutOrder.ProtoReflect.Descriptor instead.
 func (*CreateCheckoutOrder) Descriptor() ([]byte, []int) {
-	return file_messages_proto_rawDescGZIP(), []int{9}
+	return file_messages_proto_rawDescGZIP(), []int{8}
 }
 
 func (x *CreateCheckoutOrder) GetTerms() string {
@@ -847,7 +788,7 @@ type OrderCreated struct {
 
 func (x *OrderCreated) Reset() {
 	*x = OrderCreated{}
-	mi := &file_messages_proto_msgTypes[10]
+	mi := &file_messages_proto_msgTypes[9]
 	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 	ms.StoreMessageInfo(mi)
 }
@@ -859,7 +800,7 @@ func (x *OrderCreated) String() string {
 func (*OrderCreated) ProtoMessage() {}
 
 func (x *OrderCreated) ProtoReflect() protoreflect.Message {
-	mi := &file_messages_proto_msgTypes[10]
+	mi := &file_messages_proto_msgTypes[9]
 	if x != nil {
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		if ms.LoadMessageInfo() == nil {
@@ -872,7 +813,7 @@ func (x *OrderCreated) ProtoReflect() protoreflect.Message {
 
 // Deprecated: Use OrderCreated.ProtoReflect.Descriptor instead.
 func (*OrderCreated) Descriptor() ([]byte, []int) {
-	return file_messages_proto_rawDescGZIP(), []int{10}
+	return file_messages_proto_rawDescGZIP(), []int{9}
 }
 
 func (x *OrderCreated) GetOrderId() string {
@@ -897,7 +838,7 @@ type Noop struct {
 
 func (x *Noop) Reset() {
 	*x = Noop{}
-	mi := &file_messages_proto_msgTypes[11]
+	mi := &file_messages_proto_msgTypes[10]
 	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 	ms.StoreMessageInfo(mi)
 }
@@ -909,7 +850,7 @@ func (x *Noop) String() string {
 func (*Noop) ProtoMessage() {}
 
 func (x *Noop) ProtoReflect() protoreflect.Message {
-	mi := &file_messages_proto_msgTypes[11]
+	mi := &file_messages_proto_msgTypes[10]
 	if x != nil {
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		if ms.LoadMessageInfo() == nil {
@@ -922,7 +863,7 @@ func (x *Noop) ProtoReflect() protoreflect.Message {
 
 // Deprecated: Use Noop.ProtoReflect.Descriptor instead.
 func (*Noop) Descriptor() ([]byte, []int) {
-	return file_messages_proto_rawDescGZIP(), []int{11}
+	return file_messages_proto_rawDescGZIP(), []int{10}
 }
 
 type InitializeCheckout struct {
@@ -936,7 +877,7 @@ type InitializeCheckout struct {
 
 func (x *InitializeCheckout) Reset() {
 	*x = InitializeCheckout{}
-	mi := &file_messages_proto_msgTypes[12]
+	mi := &file_messages_proto_msgTypes[11]
 	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 	ms.StoreMessageInfo(mi)
 }
@@ -948,7 +889,7 @@ func (x *InitializeCheckout) String() string {
 func (*InitializeCheckout) ProtoMessage() {}
 
 func (x *InitializeCheckout) ProtoReflect() protoreflect.Message {
-	mi := &file_messages_proto_msgTypes[12]
+	mi := &file_messages_proto_msgTypes[11]
 	if x != nil {
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		if ms.LoadMessageInfo() == nil {
@@ -961,7 +902,7 @@ func (x *InitializeCheckout) ProtoReflect() protoreflect.Message {
 
 // Deprecated: Use InitializeCheckout.ProtoReflect.Descriptor instead.
 func (*InitializeCheckout) Descriptor() ([]byte, []int) {
-	return file_messages_proto_rawDescGZIP(), []int{12}
+	return file_messages_proto_rawDescGZIP(), []int{11}
 }
 
 func (x *InitializeCheckout) GetOrderId() string {
@@ -985,23 +926,254 @@ func (x *InitializeCheckout) GetPaymentInProgress() bool {
 	return false
 }
 
+type AddVoucher struct {
+	state         protoimpl.MessageState `protogen:"open.v1"`
+	Code          string                 `protobuf:"bytes,1,opt,name=code,proto3" json:"code,omitempty"`
+	Value         int64                  `protobuf:"varint,2,opt,name=value,proto3" json:"value,omitempty"`
+	VoucherRules  []string               `protobuf:"bytes,3,rep,name=voucherRules,proto3" json:"voucherRules,omitempty"`
+	Description   string                 `protobuf:"bytes,4,opt,name=description,proto3" json:"description,omitempty"`
+	unknownFields protoimpl.UnknownFields
+	sizeCache     protoimpl.SizeCache
+}
+
+func (x *AddVoucher) Reset() {
+	*x = AddVoucher{}
+	mi := &file_messages_proto_msgTypes[12]
+	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
+	ms.StoreMessageInfo(mi)
+}
+
+func (x *AddVoucher) String() string {
+	return protoimpl.X.MessageStringOf(x)
+}
+
+func (*AddVoucher) ProtoMessage() {}
+
+func (x *AddVoucher) ProtoReflect() protoreflect.Message {
+	mi := &file_messages_proto_msgTypes[12]
+	if x != nil {
+		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
+		if ms.LoadMessageInfo() == nil {
+			ms.StoreMessageInfo(mi)
+		}
+		return ms
+	}
+	return mi.MessageOf(x)
+}
+
+// Deprecated: Use AddVoucher.ProtoReflect.Descriptor instead.
+func (*AddVoucher) Descriptor() ([]byte, []int) {
+	return file_messages_proto_rawDescGZIP(), []int{12}
+}
+
+func (x *AddVoucher) GetCode() string {
+	if x != nil {
+		return x.Code
+	}
+	return ""
+}
+
+func (x *AddVoucher) GetValue() int64 {
+	if x != nil {
+		return x.Value
+	}
+	return 0
+}
+
+func (x *AddVoucher) GetVoucherRules() []string {
+	if x != nil {
+		return x.VoucherRules
+	}
+	return nil
+}
+
+func (x *AddVoucher) GetDescription() string {
+	if x != nil {
+		return x.Description
+	}
+	return ""
+}
+
+type RemoveVoucher struct {
+	state         protoimpl.MessageState `protogen:"open.v1"`
+	Id            uint32                 `protobuf:"varint,1,opt,name=id,proto3" json:"id,omitempty"`
+	unknownFields protoimpl.UnknownFields
+	sizeCache     protoimpl.SizeCache
+}
+
+func (x *RemoveVoucher) Reset() {
+	*x = RemoveVoucher{}
+	mi := &file_messages_proto_msgTypes[13]
+	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
+	ms.StoreMessageInfo(mi)
+}
+
+func (x *RemoveVoucher) String() string {
+	return protoimpl.X.MessageStringOf(x)
+}
+
+func (*RemoveVoucher) ProtoMessage() {}
+
+func (x *RemoveVoucher) ProtoReflect() protoreflect.Message {
+	mi := &file_messages_proto_msgTypes[13]
+	if x != nil {
+		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
+		if ms.LoadMessageInfo() == nil {
+			ms.StoreMessageInfo(mi)
+		}
+		return ms
+	}
+	return mi.MessageOf(x)
+}
+
+// Deprecated: Use RemoveVoucher.ProtoReflect.Descriptor instead.
+func (*RemoveVoucher) Descriptor() ([]byte, []int) {
+	return file_messages_proto_rawDescGZIP(), []int{13}
+}
+
+func (x *RemoveVoucher) GetId() uint32 {
+	if x != nil {
+		return x.Id
+	}
+	return 0
+}
+
+type UpsertSubscriptionDetails struct {
+	state         protoimpl.MessageState `protogen:"open.v1"`
+	Id            *string                `protobuf:"bytes,1,opt,name=id,proto3,oneof" json:"id,omitempty"`
+	OfferingCode  string                 `protobuf:"bytes,2,opt,name=offeringCode,proto3" json:"offeringCode,omitempty"`
+	SigningType   string                 `protobuf:"bytes,3,opt,name=signingType,proto3" json:"signingType,omitempty"`
+	Data          *anypb.Any             `protobuf:"bytes,4,opt,name=data,proto3" json:"data,omitempty"`
+	unknownFields protoimpl.UnknownFields
+	sizeCache     protoimpl.SizeCache
+}
+
+func (x *UpsertSubscriptionDetails) Reset() {
+	*x = UpsertSubscriptionDetails{}
+	mi := &file_messages_proto_msgTypes[14]
+	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
+	ms.StoreMessageInfo(mi)
+}
+
+func (x *UpsertSubscriptionDetails) String() string {
+	return protoimpl.X.MessageStringOf(x)
+}
+
+func (*UpsertSubscriptionDetails) ProtoMessage() {}
+
+func (x *UpsertSubscriptionDetails) ProtoReflect() protoreflect.Message {
+	mi := &file_messages_proto_msgTypes[14]
+	if x != nil {
+		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
+		if ms.LoadMessageInfo() == nil {
+			ms.StoreMessageInfo(mi)
+		}
+		return ms
+	}
+	return mi.MessageOf(x)
+}
+
+// Deprecated: Use UpsertSubscriptionDetails.ProtoReflect.Descriptor instead.
+func (*UpsertSubscriptionDetails) Descriptor() ([]byte, []int) {
+	return file_messages_proto_rawDescGZIP(), []int{14}
+}
+
+func (x *UpsertSubscriptionDetails) GetId() string {
+	if x != nil && x.Id != nil {
+		return *x.Id
+	}
+	return ""
+}
+
+func (x *UpsertSubscriptionDetails) GetOfferingCode() string {
+	if x != nil {
+		return x.OfferingCode
+	}
+	return ""
+}
+
+func (x *UpsertSubscriptionDetails) GetSigningType() string {
+	if x != nil {
+		return x.SigningType
+	}
+	return ""
+}
+
+func (x *UpsertSubscriptionDetails) GetData() *anypb.Any {
+	if x != nil {
+		return x.Data
+	}
+	return nil
+}
+
+type PreConditionFailed struct {
+	state         protoimpl.MessageState `protogen:"open.v1"`
+	Operation     string                 `protobuf:"bytes,1,opt,name=operation,proto3" json:"operation,omitempty"`
+	Error         string                 `protobuf:"bytes,2,opt,name=error,proto3" json:"error,omitempty"`
+	Input         *anypb.Any             `protobuf:"bytes,3,opt,name=input,proto3" json:"input,omitempty"`
+	unknownFields protoimpl.UnknownFields
+	sizeCache     protoimpl.SizeCache
+}
+
+func (x *PreConditionFailed) Reset() {
+	*x = PreConditionFailed{}
+	mi := &file_messages_proto_msgTypes[15]
+	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
+	ms.StoreMessageInfo(mi)
+}
+
+func (x *PreConditionFailed) String() string {
+	return protoimpl.X.MessageStringOf(x)
+}
+
+func (*PreConditionFailed) ProtoMessage() {}
+
+func (x *PreConditionFailed) ProtoReflect() protoreflect.Message {
+	mi := &file_messages_proto_msgTypes[15]
+	if x != nil {
+		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
+		if ms.LoadMessageInfo() == nil {
+			ms.StoreMessageInfo(mi)
+		}
+		return ms
+	}
+	return mi.MessageOf(x)
+}
+
+// Deprecated: Use PreConditionFailed.ProtoReflect.Descriptor instead.
+func (*PreConditionFailed) Descriptor() ([]byte, []int) {
+	return file_messages_proto_rawDescGZIP(), []int{15}
+}
+
+func (x *PreConditionFailed) GetOperation() string {
+	if x != nil {
+		return x.Operation
+	}
+	return ""
+}
+
+func (x *PreConditionFailed) GetError() string {
+	if x != nil {
+		return x.Error
+	}
+	return ""
+}
+
+func (x *PreConditionFailed) GetInput() *anypb.Any {
+	if x != nil {
+		return x.Input
+	}
+	return nil
+}
+
 var File_messages_proto protoreflect.FileDescriptor
 
 const file_messages_proto_rawDesc = "" +
 	"\n" +
-	"\x0emessages.proto\x12\bmessages\"\x7f\n" +
+	"\x0emessages.proto\x12\bmessages\x1a\x19google/protobuf/any.proto\"\x12\n" +
-	"\n" +
+	"\x10ClearCartRequest\"\xb7\x05\n" +
-	"AddRequest\x12\x1a\n" +
-	"\bquantity\x18\x01 \x01(\x05R\bquantity\x12\x10\n" +
-	"\x03sku\x18\x02 \x01(\tR\x03sku\x12\x18\n" +
-	"\acountry\x18\x03 \x01(\tR\acountry\x12\x1d\n" +
-	"\astoreId\x18\x04 \x01(\tH\x00R\astoreId\x88\x01\x01B\n" +
-	"\n" +
-	"\b_storeId\"<\n" +
-	"\x0eSetCartRequest\x12*\n" +
-	"\x05items\x18\x01 \x03(\v2\x14.messages.AddRequestR\x05items\"\xe9\x04\n" +
 	"\aAddItem\x12\x17\n" +
-	"\aitem_id\x18\x01 \x01(\x03R\x06itemId\x12\x1a\n" +
+	"\aitem_id\x18\x01 \x01(\rR\x06itemId\x12\x1a\n" +
 	"\bquantity\x18\x02 \x01(\x05R\bquantity\x12\x14\n" +
 	"\x05price\x18\x03 \x01(\x03R\x05price\x12\x1a\n" +
 	"\borgPrice\x18\t \x01(\x03R\borgPrice\x12\x10\n" +
@@ -1025,21 +1197,26 @@ const file_messages_proto_rawDesc = "" +
 	"\n" +
 	"sellerName\x18\x14 \x01(\tR\n" +
 	"sellerName\x12\x18\n" +
-	"\acountry\x18\x15 \x01(\tR\acountry\x12\x1b\n" +
+	"\acountry\x18\x15 \x01(\tR\acountry\x12\x1e\n" +
+	"\n" +
+	"saleStatus\x18\x18 \x01(\tR\n" +
+	"saleStatus\x12\x1b\n" +
 	"\x06outlet\x18\f \x01(\tH\x00R\x06outlet\x88\x01\x01\x12\x1d\n" +
-	"\astoreId\x18\x16 \x01(\tH\x01R\astoreId\x88\x01\x01B\t\n" +
+	"\astoreId\x18\x16 \x01(\tH\x01R\astoreId\x88\x01\x01\x12\x1f\n" +
+	"\bparentId\x18\x17 \x01(\rH\x02R\bparentId\x88\x01\x01B\t\n" +
 	"\a_outletB\n" +
 	"\n" +
-	"\b_storeId\"\x1c\n" +
+	"\b_storeIdB\v\n" +
+	"\t_parentId\"\x1c\n" +
 	"\n" +
 	"RemoveItem\x12\x0e\n" +
-	"\x02Id\x18\x01 \x01(\x03R\x02Id\"<\n" +
+	"\x02Id\x18\x01 \x01(\rR\x02Id\"<\n" +
 	"\x0eChangeQuantity\x12\x0e\n" +
-	"\x02id\x18\x01 \x01(\x03R\x02id\x12\x1a\n" +
+	"\x02Id\x18\x01 \x01(\rR\x02Id\x12\x1a\n" +
 	"\bquantity\x18\x02 \x01(\x05R\bquantity\"\x86\x02\n" +
 	"\vSetDelivery\x12\x1a\n" +
 	"\bprovider\x18\x01 \x01(\tR\bprovider\x12\x14\n" +
-	"\x05items\x18\x02 \x03(\x03R\x05items\x12<\n" +
+	"\x05items\x18\x02 \x03(\rR\x05items\x12<\n" +
 	"\vpickupPoint\x18\x03 \x01(\v2\x15.messages.PickupPointH\x00R\vpickupPoint\x88\x01\x01\x12\x18\n" +
 	"\acountry\x18\x04 \x01(\tR\acountry\x12\x10\n" +
 	"\x03zip\x18\x05 \x01(\tR\x03zip\x12\x1d\n" +
@@ -1051,7 +1228,7 @@ const file_messages_proto_rawDesc = "" +
 	"\x05_city\"\xf9\x01\n" +
 	"\x0eSetPickupPoint\x12\x1e\n" +
 	"\n" +
-	"deliveryId\x18\x01 \x01(\x03R\n" +
+	"deliveryId\x18\x01 \x01(\rR\n" +
 	"deliveryId\x12\x0e\n" +
 	"\x02id\x18\x02 \x01(\tR\x02id\x12\x17\n" +
 	"\x04name\x18\x03 \x01(\tH\x00R\x04name\x88\x01\x01\x12\x1d\n" +
@@ -1081,7 +1258,7 @@ const file_messages_proto_rawDesc = "" +
 	"\n" +
 	"\b_country\" \n" +
 	"\x0eRemoveDelivery\x12\x0e\n" +
-	"\x02id\x18\x01 \x01(\x03R\x02id\"\xb9\x01\n" +
+	"\x02id\x18\x01 \x01(\rR\x02id\"\xb9\x01\n" +
 	"\x13CreateCheckoutOrder\x12\x14\n" +
 	"\x05terms\x18\x01 \x01(\tR\x05terms\x12\x1a\n" +
 	"\bcheckout\x18\x02 \x01(\tR\bcheckout\x12\"\n" +
@@ -1098,7 +1275,25 @@ const file_messages_proto_rawDesc = "" +
 	"\x12InitializeCheckout\x12\x18\n" +
 	"\aorderId\x18\x01 \x01(\tR\aorderId\x12\x16\n" +
 	"\x06status\x18\x02 \x01(\tR\x06status\x12,\n" +
-	"\x11paymentInProgress\x18\x03 \x01(\bR\x11paymentInProgressB.Z,git.tornberg.me/go-cart-actor/proto;messagesb\x06proto3"
+	"\x11paymentInProgress\x18\x03 \x01(\bR\x11paymentInProgress\"|\n" +
+	"\n" +
+	"AddVoucher\x12\x12\n" +
+	"\x04code\x18\x01 \x01(\tR\x04code\x12\x14\n" +
+	"\x05value\x18\x02 \x01(\x03R\x05value\x12\"\n" +
+	"\fvoucherRules\x18\x03 \x03(\tR\fvoucherRules\x12 \n" +
+	"\vdescription\x18\x04 \x01(\tR\vdescription\"\x1f\n" +
+	"\rRemoveVoucher\x12\x0e\n" +
+	"\x02id\x18\x01 \x01(\rR\x02id\"\xa7\x01\n" +
+	"\x19UpsertSubscriptionDetails\x12\x13\n" +
+	"\x02id\x18\x01 \x01(\tH\x00R\x02id\x88\x01\x01\x12\"\n" +
+	"\fofferingCode\x18\x02 \x01(\tR\fofferingCode\x12 \n" +
+	"\vsigningType\x18\x03 \x01(\tR\vsigningType\x12(\n" +
+	"\x04data\x18\x04 \x01(\v2\x14.google.protobuf.AnyR\x04dataB\x05\n" +
+	"\x03_id\"t\n" +
+	"\x12PreConditionFailed\x12\x1c\n" +
+	"\toperation\x18\x01 \x01(\tR\toperation\x12\x14\n" +
+	"\x05error\x18\x02 \x01(\tR\x05error\x12*\n" +
+	"\x05input\x18\x03 \x01(\v2\x14.google.protobuf.AnyR\x05inputB.Z,git.tornberg.me/go-cart-actor/proto;messagesb\x06proto3"
 
 var (
 	file_messages_proto_rawDescOnce sync.Once
@@ -1112,30 +1307,35 @@ func file_messages_proto_rawDescGZIP() []byte {
 	return file_messages_proto_rawDescData
 }
 
-var file_messages_proto_msgTypes = make([]protoimpl.MessageInfo, 13)
+var file_messages_proto_msgTypes = make([]protoimpl.MessageInfo, 16)
 var file_messages_proto_goTypes = []any{
-	(*AddRequest)(nil),          // 0: messages.AddRequest
+	(*ClearCartRequest)(nil),          // 0: messages.ClearCartRequest
-	(*SetCartRequest)(nil),      // 1: messages.SetCartRequest
+	(*AddItem)(nil),                   // 1: messages.AddItem
-	(*AddItem)(nil),             // 2: messages.AddItem
+	(*RemoveItem)(nil),                // 2: messages.RemoveItem
-	(*RemoveItem)(nil),          // 3: messages.RemoveItem
+	(*ChangeQuantity)(nil),            // 3: messages.ChangeQuantity
-	(*ChangeQuantity)(nil),      // 4: messages.ChangeQuantity
+	(*SetDelivery)(nil),               // 4: messages.SetDelivery
-	(*SetDelivery)(nil),         // 5: messages.SetDelivery
+	(*SetPickupPoint)(nil),            // 5: messages.SetPickupPoint
-	(*SetPickupPoint)(nil),      // 6: messages.SetPickupPoint
+	(*PickupPoint)(nil),               // 6: messages.PickupPoint
-	(*PickupPoint)(nil),         // 7: messages.PickupPoint
+	(*RemoveDelivery)(nil),            // 7: messages.RemoveDelivery
-	(*RemoveDelivery)(nil),      // 8: messages.RemoveDelivery
+	(*CreateCheckoutOrder)(nil),       // 8: messages.CreateCheckoutOrder
-	(*CreateCheckoutOrder)(nil), // 9: messages.CreateCheckoutOrder
+	(*OrderCreated)(nil),              // 9: messages.OrderCreated
-	(*OrderCreated)(nil),        // 10: messages.OrderCreated
+	(*Noop)(nil),                      // 10: messages.Noop
-	(*Noop)(nil),                // 11: messages.Noop
+	(*InitializeCheckout)(nil),        // 11: messages.InitializeCheckout
-	(*InitializeCheckout)(nil),  // 12: messages.InitializeCheckout
+	(*AddVoucher)(nil),                // 12: messages.AddVoucher
+	(*RemoveVoucher)(nil),             // 13: messages.RemoveVoucher
+	(*UpsertSubscriptionDetails)(nil), // 14: messages.UpsertSubscriptionDetails
+	(*PreConditionFailed)(nil),        // 15: messages.PreConditionFailed
+	(*anypb.Any)(nil),                 // 16: google.protobuf.Any
 }
 var file_messages_proto_depIdxs = []int32{
-	0, // 0: messages.SetCartRequest.items:type_name -> messages.AddRequest
+	6,  // 0: messages.SetDelivery.pickupPoint:type_name -> messages.PickupPoint
-	7, // 1: messages.SetDelivery.pickupPoint:type_name -> messages.PickupPoint
+	16, // 1: messages.UpsertSubscriptionDetails.data:type_name -> google.protobuf.Any
-	2, // [2:2] is the sub-list for method output_type
+	16, // 2: messages.PreConditionFailed.input:type_name -> google.protobuf.Any
-	2, // [2:2] is the sub-list for method input_type
+	3,  // [3:3] is the sub-list for method output_type
-	2, // [2:2] is the sub-list for extension type_name
+	3,  // [3:3] is the sub-list for method input_type
-	2, // [2:2] is the sub-list for extension extendee
+	3,  // [3:3] is the sub-list for extension type_name
-	0, // [0:2] is the sub-list for field type_name
+	3,  // [3:3] is the sub-list for extension extendee
+	0,  // [0:3] is the sub-list for field type_name
 }
 
 func init() { file_messages_proto_init() }
@@ -1143,18 +1343,18 @@ func file_messages_proto_init() {
 	if File_messages_proto != nil {
 		return
 	}
-	file_messages_proto_msgTypes[0].OneofWrappers = []any{}
+	file_messages_proto_msgTypes[1].OneofWrappers = []any{}
-	file_messages_proto_msgTypes[2].OneofWrappers = []any{}
+	file_messages_proto_msgTypes[4].OneofWrappers = []any{}
 	file_messages_proto_msgTypes[5].OneofWrappers = []any{}
 	file_messages_proto_msgTypes[6].OneofWrappers = []any{}
-	file_messages_proto_msgTypes[7].OneofWrappers = []any{}
+	file_messages_proto_msgTypes[14].OneofWrappers = []any{}
 	type x struct{}
 	out := protoimpl.TypeBuilder{
 		File: protoimpl.DescBuilder{
 			GoPackagePath: reflect.TypeOf(x{}).PkgPath(),
 			RawDescriptor: unsafe.Slice(unsafe.StringData(file_messages_proto_rawDesc), len(file_messages_proto_rawDesc)),
 			NumEnums:      0,
-			NumMessages:   13,
+			NumMessages:   16,
 			NumExtensions: 0,
 			NumServices:   0,
 		},

pkg/promotions/eval.go

@@ -0,0 +1,724 @@
+package promotions
+
+import (
+	"errors"
+	"fmt"
+	"slices"
+	"strings"
+	"time"
+
+	"git.tornberg.me/go-cart-actor/pkg/cart"
+)
+
+var errInvalidTimeFormat = errors.New("invalid time format")
+
+// Tracer allows callers to receive structured debug information during evaluation.
+type Tracer interface {
+	Trace(event string, data map[string]any)
+}
+
+// NoopTracer is used when no tracer provided.
+type NoopTracer struct{}
+
+func (NoopTracer) Trace(string, map[string]any) {}
+
+// PromotionItem is a lightweight abstraction derived from cart.CartItem
+// for the purpose of promotion condition evaluation.
+type PromotionItem struct {
+	SKU         string
+	Quantity    int
+	Category    string
+	PriceIncVat int64
+}
+
+// PromotionEvalContext carries all dynamic data required to evaluate promotion
+// conditions. It can be constructed from a cart.CartGrain plus optional
+// customer/order metadata.
+type PromotionEvalContext struct {
+	CartTotalIncVat       int64
+	TotalItemQuantity     int
+	Items                 []PromotionItem
+	CustomerSegment       string
+	CustomerLifetimeValue float64
+	OrderCount            int
+	Now                   time.Time
+}
+
+// ContextOption allows customization of fields when building a PromotionEvalContext.
+type ContextOption func(*PromotionEvalContext)
+
+// WithCustomerSegment sets the customer segment.
+func WithCustomerSegment(seg string) ContextOption {
+	return func(c *PromotionEvalContext) { c.CustomerSegment = seg }
+}
+
+// WithCustomerLifetimeValue sets lifetime value metric.
+func WithCustomerLifetimeValue(v float64) ContextOption {
+	return func(c *PromotionEvalContext) { c.CustomerLifetimeValue = v }
+}
+
+// WithOrderCount sets historical order count.
+func WithOrderCount(n int) ContextOption {
+	return func(c *PromotionEvalContext) { c.OrderCount = n }
+}
+
+// WithNow overrides the timestamp used for date/time related conditions.
+func WithNow(t time.Time) ContextOption {
+	return func(c *PromotionEvalContext) { c.Now = t }
+}
+
+// NewContextFromCart builds a PromotionEvalContext from a CartGrain and optional metadata.
+func NewContextFromCart(g *cart.CartGrain, opts ...ContextOption) *PromotionEvalContext {
+	ctx := &PromotionEvalContext{
+		Items:             make([]PromotionItem, 0, len(g.Items)),
+		CartTotalIncVat:   0,
+		TotalItemQuantity: 0,
+		Now:               time.Now(),
+	}
+	if g.TotalPrice != nil {
+		ctx.CartTotalIncVat = g.TotalPrice.IncVat
+	}
+	for _, it := range g.Items {
+		category := ""
+		if it.Meta != nil {
+			category = it.Meta.Category
+		}
+		ctx.Items = append(ctx.Items, PromotionItem{
+			SKU:         it.Sku,
+			Quantity:    it.Quantity,
+			Category:    strings.ToLower(category),
+			PriceIncVat: it.Price.IncVat,
+		})
+		ctx.TotalItemQuantity += it.Quantity
+	}
+	for _, o := range opts {
+		o(ctx)
+	}
+	return ctx
+}
+
+// PromotionService evaluates PromotionRules against a PromotionEvalContext.
+type PromotionService struct {
+	tracer Tracer
+}
+
+// NewPromotionService constructs a PromotionService with an optional tracer.
+func NewPromotionService(t Tracer) *PromotionService {
+	if t == nil {
+		t = NoopTracer{}
+	}
+	return &PromotionService{tracer: t}
+}
+
+// EvaluationResult holds the outcome of evaluating a single rule.
+type EvaluationResult struct {
+	Rule           PromotionRule
+	Applicable     bool
+	FailedReason   string
+	MatchedActions []Action
+}
+
+// EvaluateRule determines if a single PromotionRule applies to the provided context.
+// Returns an EvaluationResult with applicability and actions (if applicable).
+func (s *PromotionService) EvaluateRule(rule PromotionRule, ctx *PromotionEvalContext) EvaluationResult {
+	s.tracer.Trace("rule_start", map[string]any{
+		"rule_id":   rule.ID,
+		"priority":  rule.Priority,
+		"status":    rule.Status,
+		"startDate": rule.StartDate,
+		"endDate":   rule.EndDate,
+	})
+	// Status gate
+	now := ctx.Now
+	switch rule.Status {
+	case StatusInactive, StatusExpired:
+		s.tracer.Trace("rule_skip_status", map[string]any{"rule_id": rule.ID, "status": rule.Status})
+		return EvaluationResult{Rule: rule, Applicable: false, FailedReason: "status"}
+	case StatusScheduled:
+		// Allow scheduled only if current time >= startDate (and within endDate if present)
+	}
+	// Date window checks (if parseable)
+	if rule.StartDate != "" {
+		if tStart, err := parseDate(rule.StartDate); err == nil {
+			if now.Before(tStart) {
+				s.tracer.Trace("rule_skip_before_start", map[string]any{"rule_id": rule.ID})
+				return EvaluationResult{Rule: rule, Applicable: false, FailedReason: "before_start"}
+			}
+		}
+	}
+	if rule.EndDate != nil && *rule.EndDate != "" {
+		if tEnd, err := parseDate(*rule.EndDate); err == nil {
+			if now.After(tEnd.Add(23*time.Hour + 59*time.Minute + 59*time.Second)) { // inclusive day
+				s.tracer.Trace("rule_skip_after_end", map[string]any{"rule_id": rule.ID})
+				return EvaluationResult{Rule: rule, Applicable: false, FailedReason: "after_end"}
+			}
+		}
+	}
+	// Usage limit
+	if rule.UsageLimit != nil && rule.UsageCount >= *rule.UsageLimit {
+		s.tracer.Trace("rule_skip_usage_limit", map[string]any{"rule_id": rule.ID, "usageCount": rule.UsageCount, "limit": *rule.UsageLimit})
+		return EvaluationResult{Rule: rule, Applicable: false, FailedReason: "usage_limit_exhausted"}
+	}
+
+	if !evaluateConditionsTrace(rule.Conditions, ctx, s.tracer, rule.ID) {
+		s.tracer.Trace("rule_conditions_failed", map[string]any{"rule_id": rule.ID})
+		return EvaluationResult{Rule: rule, Applicable: false, FailedReason: "conditions"}
+	}
+
+	s.tracer.Trace("rule_applicable", map[string]any{"rule_id": rule.ID})
+	return EvaluationResult{
+		Rule:           rule,
+		Applicable:     true,
+		MatchedActions: rule.Actions,
+	}
+}
+
+// EvaluateAll returns all applicable promotion actions given a list of rules and context.
+// Rules marked Applicable are sorted by Priority (ascending: lower number = higher precedence).
+func (s *PromotionService) EvaluateAll(rules []PromotionRule, ctx *PromotionEvalContext) ([]EvaluationResult, []Action) {
+	results := make([]EvaluationResult, 0, len(rules))
+	for _, r := range rules {
+		res := s.EvaluateRule(r, ctx)
+		results = append(results, res)
+	}
+	actions := make([]Action, 0)
+	for _, res := range orderedByPriority(results) {
+		if res.Applicable {
+			s.tracer.Trace("actions_add", map[string]any{
+				"rule_id":  res.Rule.ID,
+				"count":    len(res.MatchedActions),
+				"priority": res.Rule.Priority,
+			})
+			actions = append(actions, res.MatchedActions...)
+		}
+	}
+	s.tracer.Trace("evaluation_complete", map[string]any{
+		"rules_total": len(rules),
+		"actions":     len(actions),
+	})
+	return results, actions
+}
+
+// orderedByPriority returns results sorted by PromotionRule.Priority ascending (stable).
+func orderedByPriority(in []EvaluationResult) []EvaluationResult {
+	out := make([]EvaluationResult, len(in))
+	copy(out, in)
+	for i := 1; i < len(out); i++ {
+		j := i
+		for j > 0 && out[j-1].Rule.Priority > out[j].Rule.Priority {
+			out[j-1], out[j] = out[j], out[j-1]
+			j--
+		}
+	}
+	return out
+}
+
+// ----------------------------
+// Condition evaluation (with tracing)
+// ----------------------------
+
+func evaluateConditionsTrace(conds Conditions, ctx *PromotionEvalContext, t Tracer, ruleID string) bool {
+	for idx, c := range conds {
+		if !evaluateConditionTrace(c, ctx, t, ruleID, fmt.Sprintf("root[%d]", idx)) {
+			return false
+		}
+	}
+	return true
+}
+
+func evaluateConditionTrace(c Condition, ctx *PromotionEvalContext, t Tracer, ruleID, path string) bool {
+	if grp, ok := c.(ConditionGroup); ok {
+		return evaluateGroupTrace(grp, ctx, t, ruleID, path)
+	}
+	bc, ok := c.(BaseCondition)
+	if !ok {
+		t.Trace("cond_invalid_type", map[string]any{"rule_id": ruleID, "path": path})
+		return false
+	}
+	res := evaluateBaseCondition(bc, ctx)
+	t.Trace("cond_base", map[string]any{
+		"rule_id": ruleID,
+		"path":    path,
+		"type":    bc.Type,
+		"op":      bc.Operator,
+		"value":   bc.Value.String(),
+		"result":  res,
+	})
+	return res
+}
+
+func evaluateGroupTrace(g ConditionGroup, ctx *PromotionEvalContext, t Tracer, ruleID, path string) bool {
+	op := normalizeLogicOperator(string(g.Operator))
+	if len(g.Conditions) == 0 {
+		t.Trace("cond_group_empty", map[string]any{"rule_id": ruleID, "path": path})
+		return true
+	}
+	if op == string(LogicAND) {
+		for i, child := range g.Conditions {
+			if !evaluateConditionTrace(child, ctx, t, ruleID, path+fmt.Sprintf(".AND[%d]", i)) {
+				t.Trace("cond_group_and_fail", map[string]any{"rule_id": ruleID, "path": path})
+				return false
+			}
+		}
+		t.Trace("cond_group_and_pass", map[string]any{"rule_id": ruleID, "path": path})
+		return true
+	}
+	for i, child := range g.Conditions {
+		if evaluateConditionTrace(child, ctx, t, ruleID, path+fmt.Sprintf(".OR[%d]", i)) {
+			t.Trace("cond_group_or_pass", map[string]any{"rule_id": ruleID, "path": path})
+			return true
+		}
+	}
+	t.Trace("cond_group_or_fail", map[string]any{"rule_id": ruleID, "path": path})
+	return false
+}
+
+// Fallback non-traced evaluation (used internally by traced path)
+func evaluateConditions(conds Conditions, ctx *PromotionEvalContext) bool {
+	for _, c := range conds {
+		if !evaluateCondition(c, ctx) {
+			return false
+		}
+	}
+	return true
+}
+
+func evaluateCondition(c Condition, ctx *PromotionEvalContext) bool {
+	if grp, ok := c.(ConditionGroup); ok {
+		return evaluateGroup(grp, ctx)
+	}
+	bc, ok := c.(BaseCondition)
+	if !ok {
+		return false
+	}
+	return evaluateBaseCondition(bc, ctx)
+}
+
+func evaluateGroup(g ConditionGroup, ctx *PromotionEvalContext) bool {
+	op := normalizeLogicOperator(string(g.Operator))
+	if len(g.Conditions) == 0 {
+		return true
+	}
+	if op == string(LogicAND) {
+		for _, child := range g.Conditions {
+			if !evaluateCondition(child, ctx) {
+				return false
+			}
+		}
+		return true
+	}
+	for _, child := range g.Conditions {
+		if evaluateCondition(child, ctx) {
+			return true
+		}
+	}
+	return false
+}
+
+func evaluateBaseCondition(b BaseCondition, ctx *PromotionEvalContext) bool {
+	switch b.Type {
+	case CondCartTotal:
+		return evalNumberCompare(float64(ctx.CartTotalIncVat), b)
+	case CondItemQuantity:
+		return evalNumberCompare(float64(ctx.TotalItemQuantity), b)
+	case CondCustomerSegment:
+		return evalStringCompare(ctx.CustomerSegment, b)
+	case CondProductCategory:
+		return evalAnyItemMatch(func(it PromotionItem) bool {
+			return evalValueAgainstTarget(strings.ToLower(it.Category), b)
+		}, b, ctx)
+	case CondProductID:
+		return evalAnyItemMatch(func(it PromotionItem) bool {
+			return evalValueAgainstTarget(strings.ToLower(it.SKU), b)
+		}, b, ctx)
+	case CondCustomerLifetime:
+		return evalNumberCompare(ctx.CustomerLifetimeValue, b)
+	case CondOrderCount:
+		return evalNumberCompare(float64(ctx.OrderCount), b)
+	case CondDateRange:
+		return evalDateRange(ctx.Now, b)
+	case CondDayOfWeek:
+		return evalDayOfWeek(ctx.Now, b)
+	case CondTimeOfDay:
+		return evalTimeOfDay(ctx.Now, b)
+	default:
+		return false
+	}
+}
+
+func evalAnyItemMatch(pred func(PromotionItem) bool, b BaseCondition, ctx *PromotionEvalContext) bool {
+	if slices.ContainsFunc(ctx.Items, pred) {
+		return true
+	}
+	switch normalizeOperator(string(b.Operator)) {
+	case string(OpNotIn), string(OpNotContains):
+		return true
+	}
+	return false
+}
+
+// ----------------------------
+// Primitive evaluators
+// ----------------------------
+
+func evalNumberCompare(target float64, b BaseCondition) bool {
+	op := normalizeOperator(string(b.Operator))
+	cond, ok := b.Value.AsFloat64()
+	if !ok {
+		if list, okL := b.Value.AsFloat64Slice(); okL && (op == string(OpIn) || op == string(OpNotIn)) {
+			found := sliceFloatContains(list, target)
+			if op == string(OpIn) {
+				return found
+			}
+			return !found
+		}
+		return false
+	}
+	switch op {
+	case string(OpEquals):
+		return target == cond
+	case string(OpNotEquals):
+		return target != cond
+	case string(OpGreaterThan):
+		return target > cond
+	case string(OpLessThan):
+		return target < cond
+	case string(OpGreaterOrEqual):
+		return target >= cond
+	case string(OpLessOrEqual):
+		return target <= cond
+	default:
+		return false
+	}
+}
+
+func evalStringCompare(target string, b BaseCondition) bool {
+	op := normalizeOperator(string(b.Operator))
+	targetLower := strings.ToLower(target)
+
+	if s, ok := b.Value.AsString(); ok {
+		condLower := strings.ToLower(s)
+		switch op {
+		case string(OpEquals):
+			return targetLower == condLower
+		case string(OpNotEquals):
+			return targetLower != condLower
+		case string(OpContains):
+			return strings.Contains(targetLower, condLower)
+		case string(OpNotContains):
+			return !strings.Contains(targetLower, condLower)
+		}
+	}
+
+	if arr, ok := b.Value.AsStringSlice(); ok {
+		switch op {
+		case string(OpIn):
+			for _, v := range arr {
+				if targetLower == strings.ToLower(v) {
+					return true
+				}
+			}
+			return false
+		case string(OpNotIn):
+			for _, v := range arr {
+				if targetLower == strings.ToLower(v) {
+					return false
+				}
+			}
+			return true
+		case string(OpContains):
+			for _, v := range arr {
+				if strings.Contains(targetLower, strings.ToLower(v)) {
+					return true
+				}
+			}
+			return false
+		case string(OpNotContains):
+			for _, v := range arr {
+				if strings.Contains(targetLower, strings.ToLower(v)) {
+					return false
+				}
+			}
+			return true
+		}
+	}
+
+	return false
+}
+
+func evalValueAgainstTarget(target string, b BaseCondition) bool {
+	op := normalizeOperator(string(b.Operator))
+	tLower := strings.ToLower(target)
+
+	if s, ok := b.Value.AsString(); ok {
+		vLower := strings.ToLower(s)
+		switch op {
+		case string(OpEquals):
+			return tLower == vLower
+		case string(OpNotEquals):
+			return tLower != vLower
+		case string(OpContains):
+			return strings.Contains(tLower, vLower)
+		case string(OpNotContains):
+			return !strings.Contains(tLower, vLower)
+		case string(OpIn):
+			return tLower == vLower
+		case string(OpNotIn):
+			return tLower != vLower
+		}
+	}
+
+	if list, ok := b.Value.AsStringSlice(); ok {
+		found := false
+		for _, v := range list {
+			if tLower == strings.ToLower(v) {
+				found = true
+				break
+			}
+		}
+		switch op {
+		case string(OpIn):
+			return found
+		case string(OpNotIn):
+			return !found
+		case string(OpContains):
+			for _, v := range list {
+				if strings.Contains(tLower, strings.ToLower(v)) {
+					return true
+				}
+			}
+			return false
+		case string(OpNotContains):
+			for _, v := range list {
+				if strings.Contains(tLower, strings.ToLower(v)) {
+					return false
+				}
+			}
+			return true
+		}
+	}
+
+	return false
+}
+
+func evalDateRange(now time.Time, b BaseCondition) bool {
+	var start, end time.Time
+	if ss, ok := b.Value.AsStringSlice(); ok && len(ss) == 2 {
+		t0, e0 := parseDate(ss[0])
+		t1, e1 := parseDate(ss[1])
+		if e0 != nil || e1 != nil {
+			return false
+		}
+		start, end = t0, t1
+	} else if s, ok := b.Value.AsString(); ok {
+		parts := strings.Split(s, "..")
+		if len(parts) != 2 {
+			return false
+		}
+		t0, e0 := parseDate(parts[0])
+		t1, e1 := parseDate(parts[1])
+		if e0 != nil || e1 != nil {
+			return false
+		}
+		start, end = t0, t1
+	} else {
+		return false
+	}
+	endInclusive := end.Add(23*time.Hour + 59*time.Minute + 59*time.Second)
+	return (now.Equal(start) || now.After(start)) && (now.Equal(endInclusive) || now.Before(endInclusive))
+}
+
+func evalDayOfWeek(now time.Time, b BaseCondition) bool {
+	dow := int(now.Weekday())
+	allowed := make(map[int]struct{})
+	if arr, ok := b.Value.AsStringSlice(); ok {
+		for _, v := range arr {
+			if idx, ok := parseDayOfWeek(v); ok {
+				allowed[idx] = struct{}{}
+			}
+		}
+	} else if s, ok := b.Value.AsString(); ok {
+		for _, part := range strings.Split(s, "|") {
+			if idx, ok := parseDayOfWeek(strings.TrimSpace(part)); ok {
+				allowed[idx] = struct{}{}
+			}
+		}
+	} else {
+		return false
+	}
+
+	if len(allowed) == 0 {
+		return false
+	}
+	op := normalizeOperator(string(b.Operator))
+	_, present := allowed[dow]
+	if op == string(OpIn) || op == string(OpEquals) || op == "" {
+		return present
+	}
+	if op == string(OpNotIn) || op == string(OpNotEquals) {
+		return !present
+	}
+	return present
+}
+
+func evalTimeOfDay(now time.Time, b BaseCondition) bool {
+	var startMin, endMin int
+	if arr, ok := b.Value.AsStringSlice(); ok && len(arr) == 2 {
+		s0, e0 := parseClock(arr[0])
+		s1, e1 := parseClock(arr[1])
+		if e0 != nil || e1 != nil {
+			return false
+		}
+		startMin, endMin = s0, s1
+	} else if s, ok := b.Value.AsString(); ok {
+		parts := strings.Split(s, "-")
+		if len(parts) != 2 {
+			return false
+		}
+		s0, e0 := parseClock(parts[0])
+		s1, e1 := parseClock(parts[1])
+		if e0 != nil || e1 != nil {
+			return false
+		}
+		startMin, endMin = s0, s1
+	} else {
+		return false
+	}
+	todayMin := now.Hour()*60 + now.Minute()
+	if startMin > endMin {
+		return todayMin >= startMin || todayMin <= endMin
+	}
+	return todayMin >= startMin && todayMin <= endMin
+}
+
+// ----------------------------
+// Parsing helpers
+// ----------------------------
+
+func parseDate(s string) (time.Time, error) {
+	layouts := []string{
+		"2006-01-02",
+		time.RFC3339,
+		"2006-01-02T15:04:05Z07:00",
+	}
+	for _, l := range layouts {
+		if t, err := time.Parse(l, strings.TrimSpace(s)); err == nil {
+			return t, nil
+		}
+	}
+	return time.Time{}, errInvalidTimeFormat
+}
+
+func parseDayOfWeek(s string) (int, bool) {
+	sl := strings.ToLower(strings.TrimSpace(s))
+	switch sl {
+	case "sun", "sunday", "0":
+		return 0, true
+	case "mon", "monday", "1":
+		return 1, true
+	case "tue", "tues", "tuesday", "2":
+		return 2, true
+	case "wed", "weds", "wednesday", "3":
+		return 3, true
+	case "thu", "thur", "thurs", "thursday", "4":
+		return 4, true
+	case "fri", "friday", "5":
+		return 5, true
+	case "sat", "saturday", "6":
+		return 6, true
+	default:
+		return 0, false
+	}
+}
+
+func parseClock(s string) (int, error) {
+	s = strings.TrimSpace(s)
+	parts := strings.Split(s, ":")
+	if len(parts) != 2 {
+		return 0, errInvalidTimeFormat
+	}
+	h, err := parsePositiveInt(parts[0])
+	if err != nil {
+		return 0, err
+	}
+	m, err := parsePositiveInt(parts[1])
+	if err != nil {
+		return 0, err
+	}
+	if h < 0 || h > 23 || m < 0 || m > 59 {
+		return 0, errInvalidTimeFormat
+	}
+	return h*60 + m, nil
+}
+
+func parsePositiveInt(s string) (int, error) {
+	n := 0
+	for _, r := range s {
+		if r < '0' || r > '9' {
+			return 0, errInvalidTimeFormat
+		}
+		n = n*10 + int(r-'0')
+	}
+	return n, nil
+}
+
+func normalizeOperator(op string) string {
+	o := strings.ToLower(strings.TrimSpace(op))
+	switch o {
+	case "=", "equals", "eq":
+		return string(OpEquals)
+	case "!=", "not_equals", "neq":
+		return string(OpNotEquals)
+	case ">", "greater_than", "gt":
+		return string(OpGreaterThan)
+	case "<", "less_than", "lt":
+		return string(OpLessThan)
+	case ">=", "greater_or_equal", "ge", "gte":
+		return string(OpGreaterOrEqual)
+	case "<=", "less_or_equal", "le", "lte":
+		return string(OpLessOrEqual)
+	case "contains":
+		return string(OpContains)
+	case "not_contains":
+		return string(OpNotContains)
+	case "in":
+		return string(OpIn)
+	case "not_in":
+		return string(OpNotIn)
+	default:
+		return o
+	}
+}
+
+func normalizeLogicOperator(op string) string {
+	o := strings.ToLower(strings.TrimSpace(op))
+	switch o {
+	case "&&", "and":
+		return string(LogicAND)
+	case "||", "or":
+		return string(LogicOR)
+	default:
+		return o
+	}
+}
+
+func sliceFloatContains(list []float64, v float64) bool {
+	return slices.Contains(list, v)
+}
+
+// ----------------------------
+// Potential extension hooks
+// ----------------------------
+//
+// Future ideas:
+//   - Conflict resolution strategies (e.g., best discount wins, stackable tags)
+//   - Action transformation (e.g., applying tiered logic or bundles carefully)
+//   - Recording evaluation traces for debugging / analytics.
+//   - Tracing instrumentation for condition evaluation.
+//
+// These can be integrated by adding strategy interfaces or injecting evaluators
+// into PromotionService.
+//
+// ----------------------------
+// End of file
+// ----------------------------

pkg/promotions/eval_test.go

@@ -0,0 +1,448 @@
+package promotions
+
+import (
+	"encoding/json"
+	"slices"
+	"testing"
+	"time"
+
+	"git.tornberg.me/go-cart-actor/pkg/cart"
+)
+
+// --- Helpers ---------------------------------------------------------------
+
+func cvNum(n float64) ConditionValue {
+	b, _ := json.Marshal(n)
+	return ConditionValue{Raw: b}
+}
+
+func cvString(s string) ConditionValue {
+	b, _ := json.Marshal(s)
+	return ConditionValue{Raw: b}
+}
+
+func cvStrings(ss []string) ConditionValue {
+	b, _ := json.Marshal(ss)
+	return ConditionValue{Raw: b}
+}
+
+// testTracer captures trace events for assertions.
+type testTracer struct {
+	events []traceEvent
+}
+
+type traceEvent struct {
+	event string
+	data  map[string]any
+}
+
+func (t *testTracer) Trace(event string, data map[string]any) {
+	t.events = append(t.events, traceEvent{event: event, data: data})
+}
+
+func (t *testTracer) HasEvent(name string) bool {
+	return slices.ContainsFunc(t.events, func(e traceEvent) bool { return e.event == name })
+}
+
+func (t *testTracer) Count(name string) int {
+	c := 0
+	for _, e := range t.events {
+		if e.event == name {
+			c++
+		}
+	}
+	return c
+}
+
+// makeCart creates a cart with given total and items (each item quantity & price IncVat).
+func makeCart(totalOverride int64, items []struct {
+	sku      string
+	category string
+	qty      int
+	priceInc int64
+}) *cart.CartGrain {
+	g := cart.NewCartGrain(1, time.Now())
+	for _, it := range items {
+		p := cart.NewPriceFromIncVat(it.priceInc, 0.25)
+		g.Items = append(g.Items, &cart.CartItem{
+			Id:    uint32(len(g.Items) + 1),
+			Sku:   it.sku,
+			Price: *p,
+			TotalPrice: cart.Price{
+				IncVat:   p.IncVat * int64(it.qty),
+				VatRates: p.VatRates,
+			},
+			Quantity: it.qty,
+			Meta: &cart.ItemMeta{
+				Category: it.category,
+			},
+		})
+	}
+	// Recalculate totals
+	g.UpdateTotals()
+	if totalOverride >= 0 {
+		g.TotalPrice.IncVat = totalOverride
+	}
+	return g
+}
+
+// --- Tests -----------------------------------------------------------------
+
+func TestEvaluateRuleBasicAND(t *testing.T) {
+	g := makeCart(12000, []struct {
+		sku      string
+		category string
+		qty      int
+		priceInc int64
+	}{
+		{"SKU-1", "summer", 2, 3000},
+		{"SKU-2", "winter", 1, 6000},
+	})
+
+	ctx := NewContextFromCart(g,
+		WithCustomerSegment("vip"),
+		WithOrderCount(10),
+		WithCustomerLifetimeValue(1234.56),
+		WithNow(time.Date(2024, 6, 10, 12, 0, 0, 0, time.UTC)),
+	)
+
+	// Conditions: cart_total >= 10000 AND item_quantity >= 3 AND customer_segment = vip
+	conds := Conditions{
+		ConditionGroup{
+			ID:       "grp",
+			Type:     "group",
+			Operator: LogicAND,
+			Conditions: Conditions{
+				BaseCondition{
+					ID:       "c_cart_total",
+					Type:     CondCartTotal,
+					Operator: OpGreaterOrEqual,
+					Value:    cvNum(10000),
+				},
+				BaseCondition{
+					ID:       "c_item_qty",
+					Type:     CondItemQuantity,
+					Operator: OpGreaterOrEqual,
+					Value:    cvNum(3),
+				},
+				BaseCondition{
+					ID:       "c_segment",
+					Type:     CondCustomerSegment,
+					Operator: OpEquals,
+					Value:    cvString("vip"),
+				},
+			},
+		},
+	}
+
+	rule := PromotionRule{
+		ID:          "rule-AND",
+		Name:        "VIP Summer",
+		Description: "Test rule",
+		Status:      StatusActive,
+		Priority:    1,
+		StartDate:   "2024-06-01",
+		EndDate:     ptr("2024-06-30"),
+		Conditions:  conds,
+		Actions: []Action{
+			{ID: "a1", Type: ActionPercentageDiscount, Value: 10.0},
+		},
+		UsageLimit: ptrInt(100),
+		UsageCount: 5,
+		CreatedAt:  time.Now().Format(time.RFC3339),
+		UpdatedAt:  time.Now().Format(time.RFC3339),
+		CreatedBy:  "tester",
+	}
+
+	tracer := &testTracer{}
+	svc := NewPromotionService(tracer)
+	res := svc.EvaluateRule(rule, ctx)
+	if !res.Applicable {
+		t.Fatalf("expected rule to be applicable, failedReason=%s", res.FailedReason)
+	}
+	if len(res.MatchedActions) != 1 {
+		t.Fatalf("expected 1 action, got %d", len(res.MatchedActions))
+	}
+	if !tracer.HasEvent("rule_applicable") {
+		t.Errorf("expected tracing event rule_applicable")
+	}
+}
+
+func TestEvaluateRuleUsageLimitExhausted(t *testing.T) {
+	rule := PromotionRule{
+		ID:         "limit",
+		Name:       "Limit",
+		Status:     StatusActive,
+		Priority:   1,
+		StartDate:  "2024-01-01",
+		EndDate:    nil,
+		Conditions: Conditions{},
+		UsageLimit: ptrInt(5),
+		UsageCount: 5,
+	}
+
+	ctx := &PromotionEvalContext{Now: time.Date(2024, 2, 1, 0, 0, 0, 0, time.UTC)}
+	tracer := &testTracer{}
+	svc := NewPromotionService(tracer)
+	res := svc.EvaluateRule(rule, ctx)
+	if res.Applicable {
+		t.Fatalf("expected rule NOT applicable due to usage limit")
+	}
+	if res.FailedReason != "usage_limit_exhausted" {
+		t.Fatalf("expected failedReason usage_limit_exhausted, got %s", res.FailedReason)
+	}
+	if !tracer.HasEvent("rule_skip_usage_limit") {
+		t.Errorf("tracer missing rule_skip_usage_limit event")
+	}
+}
+
+func TestEvaluateRuleDateWindow(t *testing.T) {
+	// Start in future
+	rule := PromotionRule{
+		ID:         "date",
+		Name:       "DateWindow",
+		Status:     StatusActive,
+		Priority:   1,
+		StartDate:  "2025-01-01",
+		EndDate:    ptr("2025-01-31"),
+		Conditions: Conditions{},
+	}
+	ctx := &PromotionEvalContext{Now: time.Date(2024, 12, 15, 12, 0, 0, 0, time.UTC)}
+	tracer := &testTracer{}
+	svc := NewPromotionService(tracer)
+	res := svc.EvaluateRule(rule, ctx)
+	if res.Applicable {
+		t.Fatalf("expected rule NOT applicable (before start)")
+	}
+	if res.FailedReason != "before_start" {
+		t.Fatalf("expected failedReason before_start, got %s", res.FailedReason)
+	}
+	if !tracer.HasEvent("rule_skip_before_start") {
+		t.Errorf("missing rule_skip_before_start trace event")
+	}
+}
+
+func TestEvaluateProductCategoryIN(t *testing.T) {
+	g := makeCart(-1, []struct {
+		sku      string
+		category string
+		qty      int
+		priceInc int64
+	}{
+		{"A", "shoes", 1, 5000},
+		{"B", "bags", 1, 7000},
+	})
+
+	ctx := NewContextFromCart(g)
+	conds := Conditions{
+		BaseCondition{
+			ID:       "c_category",
+			Type:     CondProductCategory,
+			Operator: OpIn,
+			Value:    cvStrings([]string{"shoes", "hats"}),
+		},
+	}
+	rule := PromotionRule{
+		ID:         "cat-in",
+		Status:     StatusActive,
+		Priority:   10,
+		StartDate:  "2024-01-01",
+		EndDate:    nil,
+		Conditions: conds,
+		Actions: []Action{
+			{ID: "discount", Type: ActionFixedDiscount, Value: 1000},
+		},
+	}
+	tracer := &testTracer{}
+	svc := NewPromotionService(tracer)
+	res := svc.EvaluateRule(rule, ctx)
+	if !res.Applicable {
+		t.Fatalf("expected category IN rule to apply")
+	}
+	if !tracer.HasEvent("rule_applicable") {
+		t.Errorf("tracing missing rule_applicable")
+	}
+}
+
+func TestEvaluateGroupOR(t *testing.T) {
+	g := makeCart(3000, []struct {
+		sku      string
+		category string
+		qty      int
+		priceInc int64
+	}{
+		{"ONE", "x", 1, 3000},
+	})
+
+	ctx := NewContextFromCart(g)
+
+	// OR group: (cart_total >= 10000) OR (item_quantity >= 1)
+	group := ConditionGroup{
+		ID:       "grp-or",
+		Type:     "group",
+		Operator: LogicOR,
+		Conditions: Conditions{
+			BaseCondition{
+				ID:       "c_total",
+				Type:     CondCartTotal,
+				Operator: OpGreaterOrEqual,
+				Value:    cvNum(10000),
+			},
+			BaseCondition{
+				ID:       "c_qty",
+				Type:     CondItemQuantity,
+				Operator: OpGreaterOrEqual,
+				Value:    cvNum(1),
+			},
+		},
+	}
+	rule := PromotionRule{
+		ID:         "or-rule",
+		Status:     StatusActive,
+		Priority:   5,
+		StartDate:  "2024-01-01",
+		EndDate:    nil,
+		Conditions: Conditions{group},
+		Actions:    []Action{{ID: "a", Type: ActionFixedDiscount, Value: 500}},
+	}
+	tracer := &testTracer{}
+	svc := NewPromotionService(tracer)
+	res := svc.EvaluateRule(rule, ctx)
+	if !res.Applicable {
+		t.Fatalf("expected OR rule to apply (second condition true)")
+	}
+	// Ensure group pass event
+	if !tracer.HasEvent("cond_group_or_pass") {
+		t.Errorf("expected cond_group_or_pass trace event")
+	}
+}
+
+func TestEvaluateAllPriorityOrdering(t *testing.T) {
+	ctx := &PromotionEvalContext{
+		CartTotalIncVat:   20000,
+		TotalItemQuantity: 2,
+		Items: []PromotionItem{
+			{SKU: "X", Quantity: 2, Category: "general", PriceIncVat: 10000},
+		},
+		Now: time.Date(2024, 5, 10, 10, 0, 0, 0, time.UTC),
+	}
+
+	// Rule A: priority 5
+	ruleA := PromotionRule{
+		ID:         "A",
+		Status:     StatusActive,
+		Priority:   5,
+		StartDate:  "2024-01-01",
+		EndDate:    nil,
+		Conditions: Conditions{},
+		Actions: []Action{
+			{ID: "actionA", Type: ActionFixedDiscount, Value: 100},
+		},
+	}
+
+	// Rule B: priority 1
+	ruleB := PromotionRule{
+		ID:         "B",
+		Status:     StatusActive,
+		Priority:   1,
+		StartDate:  "2024-01-01",
+		EndDate:    nil,
+		Conditions: Conditions{},
+		Actions: []Action{
+			{ID: "actionB", Type: ActionFixedDiscount, Value: 200},
+		},
+	}
+
+	tracer := &testTracer{}
+	svc := NewPromotionService(tracer)
+	results, actions := svc.EvaluateAll([]PromotionRule{ruleA, ruleB}, ctx)
+	if len(results) != 2 {
+		t.Fatalf("expected 2 results, got %d", len(results))
+	}
+	if len(actions) != 2 {
+		t.Fatalf("expected 2 actions, got %d", len(actions))
+	}
+
+	// Actions should follow priority order: ruleB (1) then ruleA (5)
+	if actions[0].ID != "actionB" || actions[1].ID != "actionA" {
+		t.Fatalf("actions order invalid: %+v", actions)
+	}
+	if tracer.Count("actions_add") != 2 {
+		t.Errorf("expected 2 actions_add trace events, got %d", tracer.Count("actions_add"))
+	}
+	if !tracer.HasEvent("evaluation_complete") {
+		t.Errorf("missing evaluation_complete trace")
+	}
+}
+
+func TestDayOfWeekAndTimeOfDay(t *testing.T) {
+	// Wednesday 14:30 UTC
+	now := time.Date(2024, 6, 12, 14, 30, 0, 0, time.UTC) // 2024-06-12 is Wednesday
+	ctx := &PromotionEvalContext{
+		Now: now,
+	}
+
+	condDay := BaseCondition{
+		ID:       "dow",
+		Type:     CondDayOfWeek,
+		Operator: OpIn,
+		Value:    cvStrings([]string{"wed", "fri"}),
+	}
+	condTime := BaseCondition{
+		ID:       "tod",
+		Type:     CondTimeOfDay,
+		Operator: OpEquals, // operator is ignored for time-of-day internally
+		Value:    cvString("13:00-15:00"),
+	}
+
+	rule := PromotionRule{
+		ID:         "day-time",
+		Status:     StatusActive,
+		Priority:   1,
+		StartDate:  "2024-01-01",
+		EndDate:    nil,
+		Conditions: Conditions{condDay, condTime},
+		Actions:    []Action{{ID: "a", Type: ActionPercentageDiscount, Value: 15}},
+	}
+
+	tracer := &testTracer{}
+	svc := NewPromotionService(tracer)
+	res := svc.EvaluateRule(rule, ctx)
+	if !res.Applicable {
+		t.Fatalf("expected rule to apply for Wednesday 14:30 in window 13-15")
+	}
+}
+
+func TestDateRangeCondition(t *testing.T) {
+	now := time.Date(2024, 3, 15, 9, 0, 0, 0, time.UTC)
+	ctx := &PromotionEvalContext{Now: now}
+
+	condRange := BaseCondition{
+		ID:       "date_range",
+		Type:     CondDateRange,
+		Operator: OpEquals, // not used
+		Value:    cvStrings([]string{"2024-03-01", "2024-03-31"}),
+	}
+
+	rule := PromotionRule{
+		ID:         "range",
+		Status:     StatusActive,
+		Priority:   1,
+		StartDate:  "2024-01-01",
+		EndDate:    nil,
+		Conditions: Conditions{condRange},
+		Actions:    []Action{{ID: "a", Type: ActionFixedDiscount, Value: 500}},
+	}
+
+	tracer := &testTracer{}
+	svc := NewPromotionService(tracer)
+	res := svc.EvaluateRule(rule, ctx)
+	if !res.Applicable {
+		t.Fatalf("expected date range rule to apply for 2024-03-15")
+	}
+}
+
+// --- Utilities -------------------------------------------------------------
+
+func ptr(s string) *string { return &s }
+func ptrInt(i int) *int    { return &i }

pkg/promotions/type_test.go

@@ -0,0 +1,443 @@
+package promotions
+
+import (
+	"encoding/json"
+	"testing"
+)
+
+// sampleJSON mirrors the user's full example data (all three rules)
+var sampleJSON = []byte(`[
+  {
+    "id": "1",
+    "name": "Summer Sale 2024",
+    "description": "20% off on all summer items",
+    "status": "active",
+    "priority": 1,
+    "startDate": "2024-06-01",
+    "endDate": "2024-08-31",
+    "conditions": [
+      {
+        "id": "group1",
+        "type": "group",
+        "operator": "AND",
+        "conditions": [
+          {
+            "id": "c1",
+            "type": "product_category",
+            "operator": "in",
+            "value": ["summer", "beachwear"],
+            "label": "Product category is Summer or Beachwear"
+          },
+          {
+            "id": "c2",
+            "type": "cart_total",
+            "operator": "greater_or_equal",
+            "value": 50,
+            "label": "Cart total is at least $50"
+          }
+        ]
+      }
+    ],
+    "actions": [
+      {
+        "id": "a1",
+        "type": "percentage_discount",
+        "value": 20,
+        "label": "20% discount"
+      }
+    ],
+    "usageLimit": 1000,
+    "usageCount": 342,
+    "createdAt": "2024-05-15T10:00:00Z",
+    "updatedAt": "2024-05-20T14:30:00Z",
+    "createdBy": "admin@example.com",
+    "tags": ["seasonal", "summer"]
+  },
+  {
+    "id": "2",
+    "name": "VIP Customer Exclusive",
+    "description": "Free shipping for VIP customers",
+    "status": "active",
+    "priority": 2,
+    "startDate": "2024-01-01",
+    "endDate": null,
+    "conditions": [
+      {
+        "id": "c3",
+        "type": "customer_segment",
+        "operator": "equals",
+        "value": "vip",
+        "label": "Customer segment is VIP"
+      }
+    ],
+    "actions": [
+      {
+        "id": "a2",
+        "type": "free_shipping",
+        "value": 0,
+        "label": "Free shipping"
+      }
+    ],
+    "usageCount": 1523,
+    "createdAt": "2023-12-15T09:00:00Z",
+    "updatedAt": "2024-01-05T11:20:00Z",
+    "createdBy": "marketing@example.com",
+    "tags": ["vip", "loyalty"]
+  },
+  {
+    "id": "3",
+    "name": "Buy 2 Get 1 Free",
+    "description": "Buy 2 items, get the cheapest one free",
+    "status": "scheduled",
+    "priority": 3,
+    "startDate": "2024-12-01",
+    "endDate": "2024-12-25",
+    "conditions": [
+      {
+        "id": "c4",
+        "type": "item_quantity",
+        "operator": "greater_or_equal",
+        "value": 3,
+        "label": "Cart has at least 3 items"
+      }
+    ],
+    "actions": [
+      {
+        "id": "a3",
+        "type": "buy_x_get_y",
+        "value": 0,
+        "config": { "buy": 2, "get": 1, "discount": 100 },
+        "label": "Buy 2 Get 1 Free"
+      }
+    ],
+    "usageCount": 0,
+    "createdAt": "2024-11-01T08:00:00Z",
+    "updatedAt": "2024-11-01T08:00:00Z",
+    "createdBy": "admin@example.com",
+    "tags": ["holiday", "christmas"]
+  }
+]`)
+
+func TestDecodePromotionRulesBasic(t *testing.T) {
+	rules, err := DecodePromotionRules(sampleJSON)
+	if err != nil {
+		t.Fatalf("DecodePromotionRules failed: %v", err)
+	}
+	if len(rules) != 3 {
+		t.Fatalf("expected 3 rules, got %d", len(rules))
+	}
+
+	// Rule 1 checks
+	r1 := rules[0]
+	if r1.ID != "1" {
+		t.Errorf("rule[0].ID = %s, want 1", r1.ID)
+	}
+	if r1.Status != StatusActive {
+		t.Errorf("rule[0].Status = %s, want %s", r1.Status, StatusActive)
+	}
+	if r1.EndDate == nil || *r1.EndDate != "2024-08-31" {
+		t.Errorf("rule[0].EndDate = %v, want 2024-08-31", r1.EndDate)
+	}
+	if r1.UsageLimit == nil || *r1.UsageLimit != 1000 {
+		t.Errorf("rule[0].UsageLimit = %v, want 1000", r1.UsageLimit)
+	}
+
+	// Rule 2 checks
+	r2 := rules[1]
+	if r2.ID != "2" {
+		t.Errorf("rule[1].ID = %s, want 2", r2.ID)
+	}
+	if r2.EndDate != nil {
+		t.Errorf("rule[1].EndDate should be nil (from null), got %v", *r2.EndDate)
+	}
+	if r2.UsageLimit != nil {
+		t.Errorf("rule[1].UsageLimit should be nil (missing), got %v", *r2.UsageLimit)
+	}
+}
+
+func TestConditionDecoding(t *testing.T) {
+	rules, err := DecodePromotionRules(sampleJSON)
+	if err != nil {
+		t.Fatalf("DecodePromotionRules failed: %v", err)
+	}
+	r1 := rules[0]
+	if len(r1.Conditions) != 1 {
+		t.Fatalf("expected 1 top-level condition group, got %d", len(r1.Conditions))
+	}
+
+	grp, ok := r1.Conditions[0].(ConditionGroup)
+	if !ok {
+		t.Fatalf("top-level condition is not a group, type=%T", r1.Conditions[0])
+	}
+	if grp.Operator != LogicAND {
+		t.Errorf("group operator = %s, want AND", grp.Operator)
+	}
+
+	if len(grp.Conditions) != 2 {
+		t.Fatalf("expected 2 child conditions, got %d", len(grp.Conditions))
+	}
+
+	// First child: product_category condition with slice value
+	c0, ok := grp.Conditions[0].(BaseCondition)
+	if !ok {
+		t.Fatalf("first child not BaseCondition, got %T", grp.Conditions[0])
+	}
+	if c0.Type != CondProductCategory {
+		t.Errorf("first child type = %s, want %s", c0.Type, CondProductCategory)
+	}
+	if c0.Operator != OpIn {
+		t.Errorf("first child operator = %s, want %s", c0.Operator, OpIn)
+	}
+	if arr, ok := c0.Value.AsStringSlice(); !ok || len(arr) != 2 || arr[0] != "summer" {
+		t.Errorf("expected string slice value [summer,...], got %v", arr)
+	}
+
+	// Second child: cart_total numeric
+	c1, ok := grp.Conditions[1].(BaseCondition)
+	if !ok {
+		t.Fatalf("second child not BaseCondition, got %T", grp.Conditions[1])
+	}
+	if c1.Type != CondCartTotal {
+		t.Errorf("second child type = %s, want %s", c1.Type, CondCartTotal)
+	}
+	if val, ok := c1.Value.AsFloat64(); !ok || val != 50 {
+		t.Errorf("expected numeric value 50, got %v (ok=%v)", val, ok)
+	}
+}
+
+func TestConditionValueHelpers(t *testing.T) {
+	tests := []struct {
+		name    string
+		jsonVal string
+		wantStr string
+		wantNum *float64
+		wantSS  []string
+		wantFS  []float64
+	}{
+		{
+			name:    "string value",
+			jsonVal: `"vip"`,
+			wantStr: "vip",
+		},
+		{
+			name:    "number value",
+			jsonVal: `42`,
+			wantNum: floatPtr(42),
+		},
+		{
+			name:    "string slice",
+			jsonVal: `["a","b"]`,
+			wantSS:  []string{"a", "b"},
+		},
+		{
+			name:    "number slice int",
+			jsonVal: `[1,2,3]`,
+			wantFS:  []float64{1, 2, 3},
+		},
+		{
+			name:    "number slice float",
+			jsonVal: `[1.5,2.25]`,
+			wantFS:  []float64{1.5, 2.25},
+		},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			var cv ConditionValue
+			if err := json.Unmarshal([]byte(tc.jsonVal), &cv); err != nil {
+				t.Fatalf("unmarshal value failed: %v", err)
+			}
+			if tc.wantStr != "" {
+				if got, ok := cv.AsString(); !ok || got != tc.wantStr {
+					t.Errorf("AsString got=%q ok=%v want=%q", got, ok, tc.wantStr)
+				}
+			}
+			if tc.wantNum != nil {
+				if got, ok := cv.AsFloat64(); !ok || got != *tc.wantNum {
+					t.Errorf("AsFloat64 got=%v ok=%v want=%v", got, ok, *tc.wantNum)
+				}
+			}
+			if tc.wantSS != nil {
+				if got, ok := cv.AsStringSlice(); !ok || len(got) != len(tc.wantSS) || got[0] != tc.wantSS[0] {
+					t.Errorf("AsStringSlice got=%v ok=%v want=%v", got, ok, tc.wantSS)
+				}
+			}
+			if tc.wantFS != nil {
+				if got, ok := cv.AsFloat64Slice(); !ok || len(got) != len(tc.wantFS) {
+					t.Errorf("AsFloat64Slice got=%v ok=%v want=%v", got, ok, tc.wantFS)
+				} else {
+					for i := range got {
+						if got[i] != tc.wantFS[i] {
+							t.Errorf("AsFloat64Slice[%d]=%v want=%v", i, got[i], tc.wantFS[i])
+						}
+					}
+				}
+			}
+		})
+	}
+}
+
+func TestWalkConditionsTraversal(t *testing.T) {
+	rules, err := DecodePromotionRules(sampleJSON)
+	if err != nil {
+		t.Fatalf("DecodePromotionRules failed: %v", err)
+	}
+	visited := 0
+	WalkConditions(rules[0].Conditions, func(c Condition) bool {
+		visited++
+		return true
+	})
+	// group + 2 children
+	if visited != 3 {
+		t.Errorf("expected 3 visited conditions, got %d", visited)
+	}
+}
+
+func TestActionBundleConfigParsing(t *testing.T) {
+	jsonData := []byte(`[
+	  {
+	    "id": "bundle-1",
+	    "name": "Bundle Deal",
+	    "description": "Fixed price bundle",
+	    "status": "active",
+	    "priority": 1,
+	    "startDate": "2024-01-01",
+	    "endDate": null,
+	    "conditions": [],
+	    "actions": [
+	      {
+	        "id": "act-bundle",
+	        "type": "bundle_discount",
+	        "value": 0,
+	        "bundleConfig": {
+	          "containers": [
+	            {
+	              "id": "cont1",
+	              "name": "Shoes",
+	              "quantity": 2,
+	              "selectionType": "any",
+	              "qualifyingRules": {
+	                "type": "category",
+	                "value": "shoes"
+	              }
+	            },
+	            {
+	              "id": "cont2",
+	              "name": "Socks",
+	              "quantity": 3,
+	              "selectionType": "specific",
+	              "qualifyingRules": {
+	                "type": "product_ids",
+	                "value": ["sock-1", "sock-2"]
+	              },
+	              "allowedProducts": ["sock-1","sock-2"]
+	            }
+	          ],
+	          "pricing": {
+	            "type": "fixed_price",
+	            "value": 49.99
+	          },
+	          "requireAllContainers": true
+	        },
+	        "config": { "note": "Bundle applies to footwear + socks" }
+	      }
+	    ],
+	    "usageCount": 0,
+	    "createdAt": "2024-01-01T00:00:00Z",
+	    "updatedAt": "2024-01-01T00:00:00Z",
+	    "createdBy": "bundle@example.com",
+	    "tags": ["bundle","footwear"]
+	  }
+	]`)
+	rules, err := DecodePromotionRules(jsonData)
+	if err != nil {
+		t.Fatalf("decode failed: %v", err)
+	}
+	if len(rules) != 1 {
+		t.Fatalf("expected 1 rule, got %d", len(rules))
+	}
+	if len(rules[0].Actions) != 1 {
+		t.Fatalf("expected 1 action, got %d", len(rules[0].Actions))
+	}
+	act := rules[0].Actions[0]
+	if act.Type != ActionBundleDiscount {
+		t.Fatalf("action type = %s, want %s", act.Type, ActionBundleDiscount)
+	}
+	if act.BundleConfig == nil {
+		t.Fatalf("bundleConfig nil")
+	}
+	if act.BundleConfig.Pricing.Type != "fixed_price" {
+		t.Errorf("pricing.type = %s, want fixed_price", act.BundleConfig.Pricing.Type)
+	}
+	if act.BundleConfig.Pricing.Value != 49.99 {
+		t.Errorf("pricing.value = %v, want 49.99", act.BundleConfig.Pricing.Value)
+	}
+	if !act.BundleConfig.RequireAllContainers {
+		t.Errorf("RequireAllContainers expected true")
+	}
+	if len(act.BundleConfig.Containers) != 2 {
+		t.Fatalf("expected 2 containers, got %d", len(act.BundleConfig.Containers))
+	}
+	if act.Config == nil || act.Config["note"] != "Bundle applies to footwear + socks" {
+		t.Errorf("config.note mismatch: %v", act.Config)
+	}
+}
+
+func TestConditionValueInvalidTypes(t *testing.T) {
+	cases := []struct {
+		name string
+		raw  string
+	}{
+		{"object", `{}`},
+		{"booleanTrue", `true`},
+		{"booleanFalse", `false`},
+		{"null", `null`},
+	}
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			var cv ConditionValue
+			if err := json.Unmarshal([]byte(tc.raw), &cv); err != nil {
+				t.Fatalf("unmarshal failed: %v", err)
+			}
+			if s, ok := cv.AsString(); ok {
+				t.Errorf("AsString unexpectedly succeeded (%q) for %s", s, tc.name)
+			}
+			if n, ok := cv.AsFloat64(); ok {
+				t.Errorf("AsFloat64 unexpectedly succeeded (%v) for %s", n, tc.name)
+			}
+			if ss, ok := cv.AsStringSlice(); ok {
+				t.Errorf("AsStringSlice unexpectedly succeeded (%v) for %s", ss, tc.name)
+			}
+			if fs, ok := cv.AsFloat64Slice(); ok {
+				t.Errorf("AsFloat64Slice unexpectedly succeeded (%v) for %s", fs, tc.name)
+			}
+		})
+	}
+}
+
+func TestPromotionRuleRoundTrip(t *testing.T) {
+	orig, err := DecodePromotionRules(sampleJSON)
+	if err != nil {
+		t.Fatalf("initial decode failed: %v", err)
+	}
+	data, err := json.Marshal(orig)
+	if err != nil {
+		t.Fatalf("marshal failed: %v", err)
+	}
+	round, err := DecodePromotionRules(data)
+	if err != nil {
+		t.Fatalf("round-trip decode failed: %v", err)
+	}
+	if len(orig) != len(round) {
+		t.Fatalf("rule count mismatch: orig=%d round=%d", len(orig), len(round))
+	}
+	// spot-check first rule
+	if orig[0].Name != round[0].Name {
+		t.Errorf("first rule name mismatch: %s vs %s", orig[0].Name, round[0].Name)
+	}
+	if len(orig[0].Conditions) != len(round[0].Conditions) {
+		t.Errorf("first rule condition count mismatch: %d vs %d", len(orig[0].Conditions), len(round[0].Conditions))
+	}
+}
+
+func floatPtr(f float64) *float64 { return &f }

pkg/promotions/types.go

@@ -0,0 +1,413 @@
+package promotions
+
+import (
+	"encoding/json"
+	"errors"
+	"fmt"
+	"os"
+	"strconv"
+	"strings"
+)
+
+// -----------------------------
+// Enum-like string types
+// -----------------------------
+
+type ConditionOperator string
+
+const (
+	OpEquals         ConditionOperator = "="
+	OpNotEquals      ConditionOperator = "!="
+	OpGreaterThan    ConditionOperator = ">"
+	OpLessThan       ConditionOperator = "<"
+	OpGreaterOrEqual ConditionOperator = ">="
+	OpLessOrEqual    ConditionOperator = "<="
+	OpContains       ConditionOperator = "contains"
+	OpNotContains    ConditionOperator = "not_contains"
+	OpIn             ConditionOperator = "in"
+	OpNotIn          ConditionOperator = "not_in"
+)
+
+type ConditionType string
+
+const (
+	CondCartTotal        ConditionType = "cart_total"
+	CondItemQuantity     ConditionType = "item_quantity"
+	CondCustomerSegment  ConditionType = "customer_segment"
+	CondProductCategory  ConditionType = "product_category"
+	CondProductID        ConditionType = "product_id"
+	CondCustomerLifetime ConditionType = "customer_lifetime_value"
+	CondOrderCount       ConditionType = "order_count"
+	CondDateRange        ConditionType = "date_range"
+	CondDayOfWeek        ConditionType = "day_of_week"
+	CondTimeOfDay        ConditionType = "time_of_day"
+	CondGroup            ConditionType = "group" // synthetic value for groups
+)
+
+type ActionType string
+
+const (
+	ActionPercentageDiscount ActionType = "percentage_discount"
+	ActionFixedDiscount      ActionType = "fixed_discount"
+	ActionFreeShipping       ActionType = "free_shipping"
+	ActionBuyXGetY           ActionType = "buy_x_get_y"
+	ActionTieredDiscount     ActionType = "tiered_discount"
+	ActionBundleDiscount     ActionType = "bundle_discount"
+)
+
+type LogicOperator string
+
+const (
+	LogicAND LogicOperator = "&&"
+	LogicOR  LogicOperator = "||"
+)
+
+type PromotionStatus string
+
+const (
+	StatusActive    PromotionStatus = "active"
+	StatusInactive  PromotionStatus = "inactive"
+	StatusScheduled PromotionStatus = "scheduled"
+	StatusExpired   PromotionStatus = "expired"
+)
+
+// -----------------------------
+// Condition Value (union)
+// -----------------------------
+//
+// Represents: string | number | []string | []number
+// We store raw JSON and lazily interpret.
+
+type ConditionValue struct {
+	Raw json.RawMessage
+}
+
+func (cv *ConditionValue) UnmarshalJSON(b []byte) error {
+	if len(b) == 0 {
+		return errors.New("empty ConditionValue")
+	}
+	// Just store raw; interpretation happens via helpers.
+	cv.Raw = append(cv.Raw[0:0], b...)
+	return nil
+}
+
+// Helpers to interpret value:
+func (cv ConditionValue) AsString() (string, bool) {
+	// Treat explicit JSON null as invalid
+	if string(cv.Raw) == "null" {
+		return "", false
+	}
+	var s string
+	if err := json.Unmarshal(cv.Raw, &s); err == nil {
+		return s, true
+	}
+	return "", false
+}
+
+func (cv ConditionValue) AsFloat64() (float64, bool) {
+	if string(cv.Raw) == "null" {
+		return 0, false
+	}
+	var f float64
+	if err := json.Unmarshal(cv.Raw, &f); err == nil {
+		return f, true
+	}
+	// Attempt integer decode into float64
+	var i int64
+	if err := json.Unmarshal(cv.Raw, &i); err == nil {
+		return float64(i), true
+	}
+	return 0, false
+}
+
+func (cv ConditionValue) AsStringSlice() ([]string, bool) {
+	if string(cv.Raw) == "null" {
+		return nil, false
+	}
+	var arr []string
+	if err := json.Unmarshal(cv.Raw, &arr); err == nil {
+		return arr, true
+	}
+	return nil, false
+}
+
+func (cv ConditionValue) AsFloat64Slice() ([]float64, bool) {
+	if string(cv.Raw) == "null" {
+		return nil, false
+	}
+	var arrNum []float64
+	if err := json.Unmarshal(cv.Raw, &arrNum); err == nil {
+		return arrNum, true
+	}
+	// Try []int -> []float64
+	var arrInt []int64
+	if err := json.Unmarshal(cv.Raw, &arrInt); err == nil {
+		out := make([]float64, len(arrInt))
+		for i, v := range arrInt {
+			out[i] = float64(v)
+		}
+		return out, true
+	}
+	return nil, false
+}
+
+func (cv ConditionValue) String() string {
+	if s, ok := cv.AsString(); ok {
+		return s
+	}
+	if f, ok := cv.AsFloat64(); ok {
+		return strconv.FormatFloat(f, 'f', -1, 64)
+	}
+	if ss, ok := cv.AsStringSlice(); ok {
+		return fmt.Sprintf("%v", ss)
+	}
+	if fs, ok := cv.AsFloat64Slice(); ok {
+		return fmt.Sprintf("%v", fs)
+	}
+	return string(cv.Raw)
+}
+
+// -----------------------------
+// BaseCondition
+// -----------------------------
+
+type BaseCondition struct {
+	ID       string            `json:"id"`
+	Type     ConditionType     `json:"type"`
+	Operator ConditionOperator `json:"operator"`
+	Value    ConditionValue    `json:"value"`
+	Label    *string           `json:"label,omitempty"`
+}
+
+func (b BaseCondition) IsGroup() bool { return false }
+
+// -----------------------------
+// ConditionGroup
+// -----------------------------
+
+type ConditionGroup struct {
+	ID         string        `json:"id"`
+	Type       string        `json:"type"` // always "group"
+	Operator   LogicOperator `json:"operator"`
+	Conditions Conditions    `json:"conditions"`
+}
+
+// Custom unmarshaller ensures nested polymorphic conditions are decoded
+// using the Conditions type (which applies the raw element discriminator).
+func (g *ConditionGroup) UnmarshalJSON(b []byte) error {
+	type alias struct {
+		ID         string          `json:"id"`
+		Type       string          `json:"type"`
+		Operator   LogicOperator   `json:"operator"`
+		Conditions json.RawMessage `json:"conditions"`
+	}
+	var a alias
+	if err := json.Unmarshal(b, &a); err != nil {
+		return err
+	}
+	// Basic validation
+	if a.Type != "group" {
+		return fmt.Errorf("ConditionGroup expected type 'group', got %q", a.Type)
+	}
+
+	var conds Conditions
+	if len(a.Conditions) > 0 {
+		if err := json.Unmarshal(a.Conditions, &conds); err != nil {
+			return err
+		}
+	}
+
+	g.ID = a.ID
+	g.Type = a.Type
+	switch strings.ToLower(string(a.Operator)) {
+	case "and":
+		g.Operator = LogicAND
+	case "or":
+		g.Operator = LogicOR
+	default:
+		g.Operator = a.Operator
+	}
+	g.Conditions = conds
+	return nil
+}
+
+func (g ConditionGroup) IsGroup() bool { return true }
+
+// -----------------------------
+// Condition interface + slice
+// -----------------------------
+
+type Condition interface {
+	IsGroup() bool
+}
+
+// Internal wrapper to help decode each element.
+type rawCond struct {
+	Type string `json:"type"`
+}
+
+// Custom unmarshaler for a Condition slice
+type Conditions []Condition
+
+func (cs *Conditions) UnmarshalJSON(b []byte) error {
+	var rawList []json.RawMessage
+	if err := json.Unmarshal(b, &rawList); err != nil {
+		return err
+	}
+	out := make([]Condition, 0, len(rawList))
+	for _, elem := range rawList {
+		var hdr rawCond
+		if err := json.Unmarshal(elem, &hdr); err != nil {
+			return err
+		}
+		if hdr.Type == "group" {
+			var grp ConditionGroup
+			if err := json.Unmarshal(elem, &grp); err != nil {
+				return err
+			}
+			// Recursively decode grp.Conditions (already handled because field type is []Condition)
+			out = append(out, grp)
+		} else {
+			var bc BaseCondition
+			if err := json.Unmarshal(elem, &bc); err != nil {
+				return err
+			}
+			out = append(out, bc)
+		}
+	}
+	*cs = out
+	return nil
+}
+
+// -----------------------------
+// Bundle Structures
+// -----------------------------
+
+type BundleQualifyingRules struct {
+	Type  string      `json:"type"`  // "category" | "product_ids" | "tag" | "all"
+	Value interface{} `json:"value"` // string or []string
+}
+
+type BundleContainer struct {
+	ID              string                `json:"id"`
+	Name            string                `json:"name"`
+	Quantity        int                   `json:"quantity"`
+	SelectionType   string                `json:"selectionType"` // "any" | "specific"
+	QualifyingRules BundleQualifyingRules `json:"qualifyingRules"`
+	AllowedProducts []string              `json:"allowedProducts,omitempty"`
+}
+
+type BundlePricing struct {
+	Type  string  `json:"type"` // "fixed_price" | "percentage_discount" | "fixed_discount"
+	Value float64 `json:"value"`
+}
+
+type BundleConfig struct {
+	Containers           []BundleContainer `json:"containers"`
+	Pricing              BundlePricing     `json:"pricing"`
+	RequireAllContainers bool              `json:"requireAllContainers"`
+}
+
+// -----------------------------
+// Action
+// -----------------------------
+
+type Action struct {
+	ID           string                 `json:"id"`
+	Type         ActionType             `json:"type"`
+	Value        interface{}            `json:"value"` // number or string
+	Config       map[string]interface{} `json:"config,omitempty"`
+	BundleConfig *BundleConfig          `json:"bundleConfig,omitempty"`
+	Label        *string                `json:"label,omitempty"`
+}
+
+// -----------------------------
+// Promotion Rule
+// -----------------------------
+
+type PromotionRule struct {
+	ID          string          `json:"id"`
+	Name        string          `json:"name"`
+	Description string          `json:"description"`
+	Status      PromotionStatus `json:"status"`
+	Priority    int             `json:"priority"`
+	StartDate   string          `json:"startDate"`
+	EndDate     *string         `json:"endDate"` // null -> nil
+	Conditions  Conditions      `json:"conditions"`
+	Actions     []Action        `json:"actions"`
+	UsageLimit  *int            `json:"usageLimit,omitempty"`
+	UsageCount  int             `json:"usageCount"`
+	CreatedAt   string          `json:"createdAt"`
+	UpdatedAt   string          `json:"updatedAt"`
+	CreatedBy   string          `json:"createdBy"`
+	Tags        []string        `json:"tags"`
+}
+
+// -----------------------------
+// Promotion Stats
+// -----------------------------
+
+type PromotionStats struct {
+	TotalPromotions  int     `json:"totalPromotions"`
+	ActivePromotions int     `json:"activePromotions"`
+	TotalRevenue     float64 `json:"totalRevenue"`
+	TotalOrders      int     `json:"totalOrders"`
+	AverageDiscount  float64 `json:"averageDiscount"`
+}
+
+// -----------------------------
+// Utility: Decode array of rules
+// -----------------------------
+
+func DecodePromotionRules(data []byte) ([]PromotionRule, error) {
+	var rules []PromotionRule
+	if err := json.Unmarshal(data, &rules); err != nil {
+		return nil, err
+	}
+	return rules, nil
+}
+
+// Example helper to inspect conditions programmatically.
+func WalkConditions(conds []Condition, fn func(c Condition) bool) {
+	for _, c := range conds {
+		if !fn(c) {
+			return
+		}
+		if grp, ok := c.(ConditionGroup); ok {
+			WalkConditions(grp.Conditions, fn)
+		}
+	}
+}
+
+type PromotionState struct {
+	Promotions []PromotionRule `json:"promotions"`
+}
+
+type StateFile struct {
+	State   PromotionState `json:"state"`
+	Version int            `json:"version"`
+}
+
+func (sf *StateFile) GetPromotion(id string) (*PromotionRule, bool) {
+	for _, v := range sf.State.Promotions {
+		if v.ID == id {
+			return &v, true
+		}
+	}
+	return nil, false
+}
+
+func LoadStateFile(fileName string) (*StateFile, error) {
+	f, err := os.Open(fileName)
+	if err != nil {
+		return nil, err
+	}
+	defer f.Close()
+	dec := json.NewDecoder(f)
+	sf := &StateFile{}
+	err = dec.Decode(sf)
+	if err != nil {
+		return nil, err
+	}
+	return sf, nil
+}

pkg/proxy/remotehost.go

@@ -0,0 +1,186 @@
+package proxy
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"io"
+	"log"
+	"net/http"
+	"time"
+
+	messages "git.tornberg.me/go-cart-actor/pkg/messages"
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/credentials/insecure"
+)
+
+// RemoteHost mirrors the lightweight controller used for remote node
+// interaction.
+type RemoteHost struct {
+	host          string
+	httpBase      string
+	conn          *grpc.ClientConn
+	transport     *http.Transport
+	client        *http.Client
+	controlClient messages.ControlPlaneClient
+	missedPings   int
+}
+
+func NewRemoteHost(host string) (*RemoteHost, error) {
+
+	target := fmt.Sprintf("%s:1337", host)
+
+	conn, err := grpc.NewClient(target, grpc.WithTransportCredentials(insecure.NewCredentials()))
+
+	if err != nil {
+		log.Printf("AddRemote: dial %s failed: %v", target, err)
+		return nil, err
+	}
+
+	controlClient := messages.NewControlPlaneClient(conn)
+
+	transport := &http.Transport{
+		MaxIdleConns:        100,
+		MaxIdleConnsPerHost: 100,
+		DisableKeepAlives:   false,
+		IdleConnTimeout:     120 * time.Second,
+	}
+	client := &http.Client{Transport: transport, Timeout: 10 * time.Second}
+
+	return &RemoteHost{
+		host:          host,
+		httpBase:      fmt.Sprintf("http://%s:8080/cart", host),
+		conn:          conn,
+		transport:     transport,
+		client:        client,
+		controlClient: controlClient,
+		missedPings:   0,
+	}, nil
+}
+
+func (h *RemoteHost) Name() string {
+	return h.host
+}
+
+func (h *RemoteHost) Close() error {
+	if h.conn != nil {
+		h.conn.Close()
+	}
+	return nil
+}
+
+func (h *RemoteHost) Ping() bool {
+	var err error = errors.ErrUnsupported
+	for err != nil {
+		ctx, cancel := context.WithTimeout(context.Background(), time.Second)
+		_, err = h.controlClient.Ping(ctx, &messages.Empty{})
+		cancel()
+		if err != nil {
+			h.missedPings++
+			log.Printf("Ping %s failed (%d) %v", h.host, h.missedPings, err)
+		}
+		if !h.IsHealthy() {
+			return false
+		}
+		time.Sleep(time.Millisecond * 200)
+	}
+
+	h.missedPings = 0
+	return true
+}
+
+func (h *RemoteHost) Negotiate(knownHosts []string) ([]string, error) {
+	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+	defer cancel()
+
+	resp, err := h.controlClient.Negotiate(ctx, &messages.NegotiateRequest{
+		KnownHosts: knownHosts,
+	})
+	if err != nil {
+		h.missedPings++
+		log.Printf("Negotiate %s failed: %v", h.host, err)
+		return nil, err
+	}
+	h.missedPings = 0
+	return resp.Hosts, nil
+}
+
+func (h *RemoteHost) GetActorIds() []uint64 {
+	ctx, cancel := context.WithTimeout(context.Background(), 3*time.Second)
+	defer cancel()
+	reply, err := h.controlClient.GetLocalActorIds(ctx, &messages.Empty{})
+	if err != nil {
+		log.Printf("Init remote %s: GetCartIds error: %v", h.host, err)
+		h.missedPings++
+		return []uint64{}
+	}
+	return reply.GetIds()
+}
+
+func (h *RemoteHost) AnnounceOwnership(ownerHost string, uids []uint64) {
+	_, err := h.controlClient.AnnounceOwnership(context.Background(), &messages.OwnershipAnnounce{
+		Host: ownerHost,
+		Ids:  uids,
+	})
+	if err != nil {
+		log.Printf("ownership announce to %s failed: %v", h.host, err)
+		h.missedPings++
+		return
+	}
+	h.missedPings = 0
+}
+
+func (h *RemoteHost) AnnounceExpiry(uids []uint64) {
+	_, err := h.controlClient.AnnounceExpiry(context.Background(), &messages.ExpiryAnnounce{
+		Host: h.host,
+		Ids:  uids,
+	})
+	if err != nil {
+		log.Printf("expiry announce to %s failed: %v", h.host, err)
+		h.missedPings++
+		return
+	}
+	h.missedPings = 0
+}
+
+func (h *RemoteHost) Proxy(id uint64, w http.ResponseWriter, r *http.Request) (bool, error) {
+	target := fmt.Sprintf("%s%s", h.httpBase, r.URL.RequestURI())
+
+	req, err := http.NewRequestWithContext(r.Context(), r.Method, target, r.Body)
+	if err != nil {
+		http.Error(w, "proxy build error", http.StatusBadGateway)
+		return false, err
+	}
+	//r.Body = io.NopCloser(bytes.NewReader(bodyCopy))
+	req.Header.Set("X-Forwarded-Host", r.Host)
+
+	for k, v := range r.Header {
+		for _, vv := range v {
+			req.Header.Add(k, vv)
+		}
+	}
+	res, err := h.client.Do(req)
+	if err != nil {
+		http.Error(w, "proxy request error", http.StatusBadGateway)
+		return false, err
+	}
+	defer res.Body.Close()
+	for k, v := range res.Header {
+		for _, vv := range v {
+			w.Header().Add(k, vv)
+		}
+	}
+	w.Header().Set("X-Cart-Owner-Routed", "true")
+
+	w.WriteHeader(res.StatusCode)
+	_, copyErr := io.Copy(w, res.Body)
+	if copyErr != nil {
+		return true, copyErr
+	}
+	return true, nil
+
+}
+
+func (r *RemoteHost) IsHealthy() bool {
+	return r.missedPings < 3
+}

pkg/voucher/parser.go

@@ -0,0 +1,343 @@
+package voucher
+
+import (
+	"errors"
+	"fmt"
+	"slices"
+	"strconv"
+	"strings"
+	"unicode"
+)
+
+/*
+Package voucher - rule parser
+
+A lightweight parser for voucher rule expressions.
+
+Supported rule kinds (case-insensitive keywords):
+
+  sku=SKU1|SKU2|SKU3
+    - At least one of the listed SKUs must be present in the cart.
+
+  category=CatA|CatB|CatC
+    - At least one of the listed categories must be present.
+
+  min_total>=12345
+    - Cart total (Inc VAT) must be at least this value (int64).
+
+  min_item_price>=5000
+    - At least one individual item (Inc VAT single unit price) must be at least this value (int64).
+
+Rule list grammar (simplified):
+  rules := rule (sep rule)*
+  rule  := (sku|category) '=' valueList
+         | (min_total|min_item_price) comparator number
+  valueList := value ('|' value)*
+  comparator := '>='   (only comparator currently supported for numeric rules)
+  sep := ';' | ',' | newline
+
+Whitespace is ignored around tokens.
+
+Example:
+  sku=ABC123|XYZ999; category=Shoes|Bags
+  min_total>=10000
+  min_item_price>=2500, category=Accessories
+
+Parsing returns a RuleSet which can later be evaluated against a generic context.
+The evaluation context uses simple Item abstractions to avoid tight coupling with
+the cart implementation (which currently lives under cmd/cart and cannot be
+imported due to being in package main).
+
+This is intentionally conservative and extensible:
+  * Adding new rule kinds: extend RuleKind constants, add parse + evaluate logic.
+  * Supporting new operators: extend numeric rule parsing & evaluation.
+*/
+
+var (
+	// ErrEmptyExpression is returned when the input string has only whitespace.
+	ErrEmptyExpression = errors.New("voucher: empty rule expression")
+	// ErrInvalidRule indicates a syntactic or semantic issue with a single rule fragment.
+	ErrInvalidRule = errors.New("voucher: invalid rule")
+)
+
+// RuleKind enumerates supported rule kinds.
+type RuleKind string
+
+const (
+	RuleSku          RuleKind = "sku"
+	RuleCategory     RuleKind = "category"
+	RuleMinTotal     RuleKind = "min_total"
+	RuleMinItemPrice RuleKind = "min_item_price"
+)
+
+// ruleCondition represents a single, parsed rule.
+type ruleCondition struct {
+	Kind       RuleKind
+	StringVals []string // For sku / category multi-value list
+	MinValue   *int64   // For numeric threshold rules
+	// Operator reserved for future (e.g., >, >=, ==). Currently always ">=" for numeric kinds.
+	Operator string
+}
+
+// RuleSet groups multiple rule conditions (logical AND).
+// All conditions must pass for Applies() to return true.
+type RuleSet struct {
+	Conditions []ruleCondition
+	Source     string // original, trimmed source string
+}
+
+// Item is a minimal abstraction for evaluation (decoupled from cart domain structs).
+type Item struct {
+	Sku       string
+	Category  string
+	UnitPrice int64 // Inc VAT (single unit)
+}
+
+// EvalContext bundles cart-like data necessary for evaluation.
+type EvalContext struct {
+	Items        []Item
+	CartTotalInc int64
+}
+
+// Applies returns true if all rule conditions pass for the context.
+func (rs *RuleSet) Applies(ctx EvalContext) bool {
+	for _, c := range rs.Conditions {
+		switch c.Kind {
+		case RuleSku:
+			if !anyItem(ctx.Items, func(it Item) bool {
+				return containsFold(c.StringVals, it.Sku)
+			}) {
+				return false
+			}
+		case RuleCategory:
+			if !anyItem(ctx.Items, func(it Item) bool {
+				return containsFold(c.StringVals, it.Category)
+			}) {
+				return false
+			}
+		case RuleMinTotal:
+			if c.MinValue == nil || ctx.CartTotalInc < *c.MinValue {
+				return false
+			}
+		case RuleMinItemPrice:
+			if c.MinValue == nil {
+				return false
+			}
+			if !anyItem(ctx.Items, func(it Item) bool {
+				return it.UnitPrice >= *c.MinValue
+			}) {
+				return false
+			}
+		default:
+			// Unknown kinds fail closed to avoid granting unintended discounts.
+			return false
+		}
+	}
+	return true
+}
+
+// anyItem returns true if predicate matches any item.
+func anyItem(items []Item, pred func(Item) bool) bool {
+	return slices.ContainsFunc(items, pred)
+}
+
+// ParseRules parses a rule expression into a RuleSet.
+func ParseRules(input string) (*RuleSet, error) {
+	trimmed := strings.TrimSpace(input)
+	if trimmed == "" {
+		return nil, ErrEmptyExpression
+	}
+
+	fragments := splitRuleFragments(trimmed)
+	if len(fragments) == 0 {
+		return nil, ErrInvalidRule
+	}
+
+	var conditions []ruleCondition
+	for _, frag := range fragments {
+		if frag == "" {
+			continue
+		}
+		c, err := parseFragment(frag)
+		if err != nil {
+			return nil, fmt.Errorf("%w: %s (%v)", ErrInvalidRule, frag, err)
+		}
+		conditions = append(conditions, c)
+	}
+
+	if len(conditions) == 0 {
+		return nil, ErrInvalidRule
+	}
+
+	return &RuleSet{
+		Conditions: conditions,
+		Source:     trimmed,
+	}, nil
+}
+
+// splitRuleFragments splits on ; , or newline, while respecting basic structure.
+func splitRuleFragments(s string) []string {
+	// Normalize line endings
+	s = strings.ReplaceAll(s, "\r\n", "\n")
+
+	// We allow separators: newline, semicolon, comma.
+	seps := func(r rune) bool {
+		return r == ';' || r == '\n' || r == ','
+	}
+	raw := strings.FieldsFunc(s, seps)
+	out := make([]string, 0, len(raw))
+	for _, f := range raw {
+		t := strings.TrimSpace(f)
+		if t != "" {
+			out = append(out, t)
+		}
+	}
+	return out
+}
+
+// parseFragment parses an individual rule fragment.
+func parseFragment(frag string) (ruleCondition, error) {
+	lower := strings.ToLower(frag)
+
+	// Numeric rules have form: <kind> >= number
+	if strings.HasPrefix(lower, string(RuleMinTotal)) ||
+		strings.HasPrefix(lower, string(RuleMinItemPrice)) {
+
+		return parseNumericRule(frag)
+	}
+
+	// Key=Value list rules (sku / category).
+	if i := strings.Index(frag, "="); i > 0 {
+		key := strings.TrimSpace(frag[:i])
+		valPart := strings.TrimSpace(frag[i+1:])
+		if key == "" || valPart == "" {
+			return ruleCondition{}, errors.New("empty key/value")
+		}
+		kind := RuleKind(strings.ToLower(key))
+		switch kind {
+		case RuleSku, RuleCategory:
+			values := splitAndClean(valPart, "|")
+			if len(values) == 0 {
+				return ruleCondition{}, errors.New("empty value list")
+			}
+			return ruleCondition{
+				Kind:       kind,
+				StringVals: values,
+			}, nil
+		default:
+			return ruleCondition{}, fmt.Errorf("unsupported key '%s'", key)
+		}
+	}
+
+	return ruleCondition{}, fmt.Errorf("unrecognized fragment '%s'", frag)
+}
+
+func parseNumericRule(frag string) (ruleCondition, error) {
+	// Support only '>=' for now.
+	var kind RuleKind
+	var rest string
+
+	fragTrim := strings.TrimSpace(frag)
+
+	switch {
+	case strings.HasPrefix(strings.ToLower(fragTrim), string(RuleMinTotal)):
+		kind = RuleMinTotal
+		rest = strings.TrimSpace(fragTrim[len(RuleMinTotal):])
+	case strings.HasPrefix(strings.ToLower(fragTrim), string(RuleMinItemPrice)):
+		kind = RuleMinItemPrice
+		rest = strings.TrimSpace(fragTrim[len(RuleMinItemPrice):])
+	default:
+		return ruleCondition{}, fmt.Errorf("unknown numeric rule '%s'", frag)
+	}
+
+	// Expect operator and number (>= <number>)
+	rest = stripLeadingSpace(rest)
+	if !strings.HasPrefix(rest, ">=") {
+		return ruleCondition{}, fmt.Errorf("expected '>=' in '%s'", frag)
+	}
+	numStr := strings.TrimSpace(rest[2:])
+	if numStr == "" {
+		return ruleCondition{}, fmt.Errorf("missing numeric value in '%s'", frag)
+	}
+
+	value, err := strconv.ParseInt(numStr, 10, 64)
+	if err != nil {
+		return ruleCondition{}, fmt.Errorf("invalid number '%s': %v", numStr, err)
+	}
+	if value < 0 {
+		return ruleCondition{}, fmt.Errorf("negative threshold %d", value)
+	}
+
+	return ruleCondition{
+		Kind:     kind,
+		MinValue: &value,
+		Operator: ">=",
+	}, nil
+}
+
+func stripLeadingSpace(s string) string {
+	for len(s) > 0 && unicode.IsSpace(rune(s[0])) {
+		s = s[1:]
+	}
+	return s
+}
+
+func splitAndClean(s string, sep string) []string {
+	raw := strings.Split(s, sep)
+	out := make([]string, 0, len(raw))
+	for _, r := range raw {
+		t := strings.TrimSpace(r)
+		if t != "" {
+			out = append(out, t)
+		}
+	}
+	return out
+}
+
+func containsFold(list []string, candidate string) bool {
+	for _, v := range list {
+		if strings.EqualFold(v, candidate) {
+			return true
+		}
+	}
+	return false
+}
+
+// Describe returns a human-friendly summary of the parsed rule set.
+func (rs *RuleSet) Describe() string {
+	if rs == nil {
+		return "<nil>"
+	}
+	var parts []string
+	for _, c := range rs.Conditions {
+		switch c.Kind {
+		case RuleSku, RuleCategory:
+			parts = append(parts, fmt.Sprintf("%s in (%s)", c.Kind, strings.Join(c.StringVals, "|")))
+		case RuleMinTotal, RuleMinItemPrice:
+			if c.MinValue != nil {
+				parts = append(parts, fmt.Sprintf("%s %s %d", c.Kind, c.OperatorOr(">="), *c.MinValue))
+			}
+		default:
+			parts = append(parts, fmt.Sprintf("unknown(%s)", c.Kind))
+		}
+	}
+	return strings.Join(parts, " AND ")
+}
+
+func (c ruleCondition) OperatorOr(def string) string {
+	if c.Operator == "" {
+		return def
+	}
+	return c.Operator
+}
+
+// --- Convenience helpers for incremental adoption ---
+
+// MustParseRules panics on parse error (useful in tests or static initialization).
+func MustParseRules(expr string) *RuleSet {
+	rs, err := ParseRules(expr)
+	if err != nil {
+		panic(err)
+	}
+	return rs
+}

pkg/voucher/parser_test.go

@@ -0,0 +1,205 @@
+package voucher
+
+import (
+	"errors"
+	"testing"
+)
+
+func TestParseRules_SimpleSku(t *testing.T) {
+	rs, err := ParseRules("sku=ABC123|XYZ999|def456")
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if len(rs.Conditions) != 1 {
+		t.Fatalf("expected 1 condition got %d", len(rs.Conditions))
+	}
+	c := rs.Conditions[0]
+	if c.Kind != RuleSku {
+		t.Fatalf("expected kind sku got %s", c.Kind)
+	}
+	if len(c.StringVals) != 3 {
+		t.Fatalf("expected 3 sku values got %d", len(c.StringVals))
+	}
+	want := []string{"ABC123", "XYZ999", "def456"}
+	for i, v := range want {
+		if c.StringVals[i] != v {
+			t.Fatalf("expected sku[%d]=%s got %s", i, v, c.StringVals[i])
+		}
+	}
+}
+
+func TestRuleCartTotal(t *testing.T) {
+	rs, err := ParseRules("min_total>=500000")
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if len(rs.Conditions) != 1 {
+		t.Fatalf("expected 1 condition got %d", len(rs.Conditions))
+	}
+	c := rs.Conditions[0]
+	if c.Kind != RuleMinTotal {
+		t.Fatalf("expected kind cart total got %s", c.Kind)
+	}
+	ctx := EvalContext{
+		Items: []Item{
+			Item{
+				Sku: "123",
+			},
+		},
+		CartTotalInc: 400000,
+	}
+	applied := rs.Applies(ctx)
+	if applied {
+		t.Fatalf("expected")
+	}
+}
+
+func TestParseRules_CategoryAndSkuMixedSeparators(t *testing.T) {
+	rs, err := ParseRules("  category=Shoes|Bags ; sku= A | B , min_total>=1000\nmin_item_price>=500")
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if len(rs.Conditions) != 4 {
+		t.Fatalf("expected 4 conditions got %d", len(rs.Conditions))
+	}
+
+	kinds := []RuleKind{RuleCategory, RuleSku, RuleMinTotal, RuleMinItemPrice}
+	for i, k := range kinds {
+		if rs.Conditions[i].Kind != k {
+			t.Fatalf("expected condition[%d] kind %s got %s", i, k, rs.Conditions[i].Kind)
+		}
+	}
+
+	// Validate numeric thresholds
+	if rs.Conditions[2].MinValue == nil || *rs.Conditions[2].MinValue != 1000 {
+		t.Fatalf("expected min_total>=1000 got %+v", rs.Conditions[2])
+	}
+	if rs.Conditions[3].MinValue == nil || *rs.Conditions[3].MinValue != 500 {
+		t.Fatalf("expected min_item_price>=500 got %+v", rs.Conditions[3])
+	}
+}
+
+func TestParseRules_Empty(t *testing.T) {
+	_, err := ParseRules("   \n  ")
+	if !errors.Is(err, ErrEmptyExpression) {
+		t.Fatalf("expected ErrEmptyExpression got %v", err)
+	}
+}
+
+func TestParseRules_Invalid(t *testing.T) {
+	_, err := ParseRules("unknown=foo")
+	if err == nil {
+		t.Fatal("expected error for unknown key")
+	}
+	_, err = ParseRules("min_total>100") // wrong operator
+	if err == nil {
+		t.Fatal("expected error for wrong operator")
+	}
+	_, err = ParseRules("min_total>=") // missing value
+	if err == nil {
+		t.Fatal("expected error for missing numeric value")
+	}
+}
+
+func TestRuleSet_Applies(t *testing.T) {
+	rs := MustParseRules("sku=ABC123|XYZ999; category=Shoes|min_total>=10000; min_item_price>=3000")
+
+	ctx := EvalContext{
+		Items: []Item{
+			{Sku: "ABC123", Category: "Shoes", UnitPrice: 2500},
+			{Sku: "FFF000", Category: "Accessories", UnitPrice: 3200},
+		},
+		CartTotalInc: 12000,
+	}
+
+	if !rs.Applies(ctx) {
+		t.Fatalf("expected rules to apply")
+	}
+
+	// Fail due to missing sku/category
+	ctx2 := EvalContext{
+		Items: []Item{
+			{Sku: "NOPE", Category: "Different", UnitPrice: 4000},
+		},
+		CartTotalInc: 20000,
+	}
+	if rs.Applies(ctx2) {
+		t.Fatalf("expected rules NOT to apply (sku/category mismatch)")
+	}
+
+	// Fail due to min_total
+	ctx3 := EvalContext{
+		Items: []Item{
+			{Sku: "ABC123", Category: "Shoes", UnitPrice: 2500},
+			{Sku: "FFF000", Category: "Accessories", UnitPrice: 3200},
+		},
+		CartTotalInc: 9000,
+	}
+	if rs.Applies(ctx3) {
+		t.Fatalf("expected rules NOT to apply (min_total not reached)")
+	}
+
+	// Fail due to min_item_price (no item >=3000)
+	ctx4 := EvalContext{
+		Items: []Item{
+			{Sku: "ABC123", Category: "Shoes", UnitPrice: 2500},
+			{Sku: "FFF000", Category: "Accessories", UnitPrice: 2800},
+		},
+		CartTotalInc: 15000,
+	}
+	if rs.Applies(ctx4) {
+		t.Fatalf("expected rules NOT to apply (min_item_price not satisfied)")
+	}
+}
+
+func TestRuleSet_Applies_CaseInsensitive(t *testing.T) {
+	rs := MustParseRules("SKU=abc123|xyz999; CATEGORY=Shoes")
+	ctx := EvalContext{
+		Items: []Item{
+			{Sku: "AbC123", Category: "shoes", UnitPrice: 1000},
+		},
+		CartTotalInc: 1000,
+	}
+	if !rs.Applies(ctx) {
+		t.Fatalf("expected rules to apply (case-insensitive match)")
+	}
+}
+
+func TestDescribe(t *testing.T) {
+	rs := MustParseRules("sku=A|B|min_total>=500")
+	desc := rs.Describe()
+	// Loose assertions to avoid over-specification
+	if desc == "" {
+		t.Fatalf("expected non-empty description")
+	}
+	if !(contains(desc, "sku") && contains(desc, "min_total")) {
+		t.Fatalf("description missing expected parts: %s", desc)
+	}
+}
+
+func contains(haystack, needle string) bool {
+	return len(haystack) >= len(needle) && indexOf(haystack, needle) >= 0
+}
+
+// Simple substring search (avoid importing strings to show intent explicitly here)
+func indexOf(s, sub string) int {
+outer:
+	for i := 0; i+len(sub) <= len(s); i++ {
+		for j := 0; j < len(sub); j++ {
+			if s[i+j] != sub[j] {
+				continue outer
+			}
+		}
+		return i
+	}
+	return -1
+}
+
+func TestMustParseRules_Panics(t *testing.T) {
+	defer func() {
+		if r := recover(); r == nil {
+			t.Fatalf("expected panic for invalid expression")
+		}
+	}()
+	MustParseRules("~~ totally invalid ~~")
+}

pkg/voucher/service.go

@@ -0,0 +1,84 @@
+package voucher
+
+import (
+	"encoding/json"
+	"errors"
+	"fmt"
+	"os"
+
+	"git.tornberg.me/go-cart-actor/pkg/messages"
+)
+
+type Rule struct {
+	Type  string `json:"type"`
+	Value int64  `json:"value"`
+}
+
+type Voucher struct {
+	Code        string `json:"code"`
+	Value       int64  `json:"value"`
+	Rules       string `json:"rules"`
+	Description string `json:"description,omitempty"`
+}
+
+type Service struct {
+	// Add fields here
+}
+
+var ErrInvalidCode = errors.New("invalid vouchercode")
+
+func (s *Service) GetVoucher(code string) (*messages.AddVoucher, error) {
+	if code == "" {
+		return nil, ErrInvalidCode
+	}
+	sf, err := LoadStateFile("data/vouchers.json")
+	if err != nil {
+		return nil, err
+	}
+	v, ok := sf.GetVoucher(code)
+	if !ok {
+		return nil, fmt.Errorf("no voucher found for code: %s", code)
+	}
+
+	return &messages.AddVoucher{
+		Code:        code,
+		Value:       v.Value,
+		Description: v.Description,
+		VoucherRules: []string{
+			v.Rules,
+		},
+	}, nil
+}
+
+type State struct {
+	Vouchers []Voucher `json:"vouchers"`
+}
+
+type StateFile struct {
+	State   State `json:"state"`
+	Version int   `json:"version"`
+}
+
+func (sf *StateFile) GetVoucher(code string) (*Voucher, bool) {
+	for _, v := range sf.State.Vouchers {
+		if v.Code == code {
+			return &v, true
+		}
+	}
+	return nil, false
+}
+
+func LoadStateFile(fileName string) (*StateFile, error) {
+	f, err := os.Open(fileName)
+	if err != nil {
+		return nil, err
+	}
+	defer f.Close()
+	dec := json.NewDecoder(f)
+	sf := &StateFile{}
+	err = dec.Decode(sf)
+	if err != nil {
+		return nil, err
+	}
+	return sf, nil
+}

pool-server.go

@@ -1,398 +0,0 @@
-package main
-
-import (
-	"bytes"
-	"encoding/json"
-	"fmt"
-	"log"
-	"math/rand"
-	"net/http"
-	"strconv"
-	"time"
-
-	messages "git.tornberg.me/go-cart-actor/proto"
-)
-
-type PoolServer struct {
-	pod_name string
-	pool     GrainPool
-}
-
-func NewPoolServer(pool GrainPool, pod_name string) *PoolServer {
-	return &PoolServer{
-		pod_name: pod_name,
-		pool:     pool,
-	}
-}
-
-func (s *PoolServer) process(id CartId, mutation interface{}) (*messages.CartState, error) {
-	grain, err := s.pool.Apply(id, mutation)
-	if err != nil {
-		return nil, err
-	}
-	return ToCartState(grain), nil
-}
-
-func (s *PoolServer) HandleGet(w http.ResponseWriter, r *http.Request, id CartId) error {
-	grain, err := s.pool.Get(id)
-	if err != nil {
-		return err
-	}
-
-	return s.WriteResult(w, ToCartState(grain))
-}
-
-func (s *PoolServer) HandleAddSku(w http.ResponseWriter, r *http.Request, id CartId) error {
-	sku := r.PathValue("sku")
-	data, err := s.process(id, &messages.AddRequest{Sku: sku, Quantity: 1})
-	if err != nil {
-		return err
-	}
-	return s.WriteResult(w, data)
-}
-
-func ErrorHandler(fn func(w http.ResponseWriter, r *http.Request) error) func(w http.ResponseWriter, r *http.Request) {
-	return func(w http.ResponseWriter, r *http.Request) {
-		err := fn(w, r)
-		if err != nil {
-			log.Printf("Server error, not remote error: %v\n", err)
-			w.WriteHeader(http.StatusInternalServerError)
-			w.Write([]byte(err.Error()))
-		}
-	}
-}
-
-func (s *PoolServer) WriteResult(w http.ResponseWriter, result *messages.CartState) error {
-	w.Header().Set("Content-Type", "application/json")
-	w.Header().Set("Cache-Control", "no-cache")
-	w.Header().Set("Access-Control-Allow-Origin", "*")
-	w.Header().Set("X-Pod-Name", s.pod_name)
-	if result == nil {
-
-		w.WriteHeader(http.StatusInternalServerError)
-
-		return nil
-	}
-	w.WriteHeader(http.StatusOK)
-	enc := json.NewEncoder(w)
-	err := enc.Encode(result)
-	return err
-}
-
-func (s *PoolServer) HandleDeleteItem(w http.ResponseWriter, r *http.Request, id CartId) error {
-
-	itemIdString := r.PathValue("itemId")
-	itemId, err := strconv.Atoi(itemIdString)
-	if err != nil {
-		return err
-	}
-	data, err := s.process(id, &messages.RemoveItem{Id: int64(itemId)})
-	if err != nil {
-		return err
-	}
-	return s.WriteResult(w, data)
-}
-
-type SetDelivery struct {
-	Provider    string                `json:"provider"`
-	Items       []int64               `json:"items"`
-	PickupPoint *messages.PickupPoint `json:"pickupPoint,omitempty"`
-}
-
-func (s *PoolServer) HandleSetDelivery(w http.ResponseWriter, r *http.Request, id CartId) error {
-
-	delivery := SetDelivery{}
-	err := json.NewDecoder(r.Body).Decode(&delivery)
-	if err != nil {
-		return err
-	}
-	data, err := s.process(id, &messages.SetDelivery{
-		Provider:    delivery.Provider,
-		Items:       delivery.Items,
-		PickupPoint: delivery.PickupPoint,
-	})
-	if err != nil {
-		return err
-	}
-	return s.WriteResult(w, data)
-}
-
-func (s *PoolServer) HandleSetPickupPoint(w http.ResponseWriter, r *http.Request, id CartId) error {
-
-	deliveryIdString := r.PathValue("deliveryId")
-	deliveryId, err := strconv.Atoi(deliveryIdString)
-	if err != nil {
-		return err
-	}
-	pickupPoint := messages.PickupPoint{}
-	err = json.NewDecoder(r.Body).Decode(&pickupPoint)
-	if err != nil {
-		return err
-	}
-	reply, err := s.process(id, &messages.SetPickupPoint{
-		DeliveryId: int64(deliveryId),
-		Id:         pickupPoint.Id,
-		Name:       pickupPoint.Name,
-		Address:    pickupPoint.Address,
-		City:       pickupPoint.City,
-		Zip:        pickupPoint.Zip,
-		Country:    pickupPoint.Country,
-	})
-	if err != nil {
-		return err
-	}
-	return s.WriteResult(w, reply)
-}
-
-func (s *PoolServer) HandleRemoveDelivery(w http.ResponseWriter, r *http.Request, id CartId) error {
-
-	deliveryIdString := r.PathValue("deliveryId")
-	deliveryId, err := strconv.Atoi(deliveryIdString)
-	if err != nil {
-		return err
-	}
-	reply, err := s.process(id, &messages.RemoveDelivery{Id: int64(deliveryId)})
-	if err != nil {
-		return err
-	}
-	return s.WriteResult(w, reply)
-}
-
-func (s *PoolServer) HandleQuantityChange(w http.ResponseWriter, r *http.Request, id CartId) error {
-	changeQuantity := messages.ChangeQuantity{}
-	err := json.NewDecoder(r.Body).Decode(&changeQuantity)
-	if err != nil {
-		return err
-	}
-	reply, err := s.process(id, &changeQuantity)
-	if err != nil {
-		return err
-	}
-	return s.WriteResult(w, reply)
-}
-
-func (s *PoolServer) HandleSetCartItems(w http.ResponseWriter, r *http.Request, id CartId) error {
-	setCartItems := messages.SetCartRequest{}
-	err := json.NewDecoder(r.Body).Decode(&setCartItems)
-	if err != nil {
-		return err
-	}
-	reply, err := s.process(id, &setCartItems)
-	if err != nil {
-		return err
-	}
-	return s.WriteResult(w, reply)
-}
-
-func (s *PoolServer) HandleAddRequest(w http.ResponseWriter, r *http.Request, id CartId) error {
-	addRequest := messages.AddRequest{}
-	err := json.NewDecoder(r.Body).Decode(&addRequest)
-	if err != nil {
-		return err
-	}
-	reply, err := s.process(id, &addRequest)
-	if err != nil {
-		return err
-	}
-	return s.WriteResult(w, reply)
-}
-
-func (s *PoolServer) HandleConfirmation(w http.ResponseWriter, r *http.Request, id CartId) error {
-	orderId := r.PathValue("orderId")
-	if orderId == "" {
-		return fmt.Errorf("orderId is empty")
-	}
-	order, err := KlarnaInstance.GetOrder(orderId)
-
-	if err != nil {
-		return err
-	}
-
-	w.Header().Set("Content-Type", "application/json")
-	w.Header().Set("X-Pod-Name", s.pod_name)
-	w.Header().Set("Cache-Control", "no-cache")
-	w.Header().Set("Access-Control-Allow-Origin", "*")
-	w.WriteHeader(http.StatusOK)
-	return json.NewEncoder(w).Encode(order)
-}
-
-func (s *PoolServer) CreateOrUpdateCheckout(host string, id CartId) (*CheckoutOrder, error) {
-	meta := &CheckoutMeta{
-		Terms:        fmt.Sprintf("https://%s/terms", host),
-		Checkout:     fmt.Sprintf("https://%s/checkout?order_id={checkout.order.id}", host),
-		Confirmation: fmt.Sprintf("https://%s/confirmation/{checkout.order.id}", host),
-		Validation:   fmt.Sprintf("https://%s/validate", host),
-		Push:         fmt.Sprintf("https://%s/push?order_id={checkout.order.id}", host),
-		Country:      getCountryFromHost(host),
-	}
-
-	// Get current grain state (may be local or remote)
-	grain, err := s.pool.Get(id)
-	if err != nil {
-		return nil, err
-	}
-
-	// Build pure checkout payload
-	payload, _, err := BuildCheckoutOrderPayload(grain, meta)
-	if err != nil {
-		return nil, err
-	}
-
-	if grain.OrderReference != "" {
-		return KlarnaInstance.UpdateOrder(grain.OrderReference, bytes.NewReader(payload))
-	} else {
-		return KlarnaInstance.CreateOrder(bytes.NewReader(payload))
-	}
-}
-
-func (s *PoolServer) ApplyCheckoutStarted(klarnaOrder *CheckoutOrder, id CartId) (*CartGrain, error) {
-	// Persist initialization state via mutation (best-effort)
-	return s.pool.Apply(id, &messages.InitializeCheckout{
-		OrderId:           klarnaOrder.ID,
-		Status:            klarnaOrder.Status,
-		PaymentInProgress: true,
-	})
-}
-
-func (s *PoolServer) HandleCheckout(w http.ResponseWriter, r *http.Request, id CartId) error {
-	klarnaOrder, err := s.CreateOrUpdateCheckout(r.Host, id)
-	if err != nil {
-		return err
-	}
-
-	s.ApplyCheckoutStarted(klarnaOrder, id)
-
-	w.Header().Set("Content-Type", "application/json")
-	return json.NewEncoder(w).Encode(klarnaOrder)
-}
-
-func NewCartId() CartId {
-	// Deprecated: legacy random/time based cart id generator.
-	// Retained for compatibility; new code should prefer canonical CartID path.
-	cid, err := NewCartID()
-	if err != nil {
-		// Fallback to legacy method only if crypto/rand fails
-		id := time.Now().UnixNano() + rand.Int63()
-		return ToCartId(fmt.Sprintf("%d", id))
-	}
-	return CartIDToLegacy(cid)
-}
-
-func CookieCartIdHandler(fn func(w http.ResponseWriter, r *http.Request, cartId CartId) error) func(w http.ResponseWriter, r *http.Request) error {
-	return func(w http.ResponseWriter, r *http.Request) error {
-		// Extract / normalize cookie (preserve legacy textual IDs without rewriting).
-		var legacy CartId
-		cookies := r.CookiesNamed("cartid")
-		if len(cookies) == 0 {
-			// No cookie -> generate new canonical base62 id.
-			cid, generated, _, err := CanonicalizeOrLegacy("")
-			if err != nil {
-				return fmt.Errorf("failed to generate cart id: %w", err)
-			}
-			legacy = CartIDToLegacy(cid)
-			if generated {
-				http.SetCookie(w, &http.Cookie{
-					Name:     "cartid",
-					Value:    cid.String(),
-					Secure:   r.TLS != nil,
-					HttpOnly: true,
-					Path:     "/",
-					Expires:  time.Now().AddDate(0, 0, 14),
-					SameSite: http.SameSiteLaxMode,
-				})
-				w.Header().Set("Set-Cart-Id", cid.String())
-			}
-		} else {
-			raw := cookies[0].Value
-			cid, generated, wasBase62, err := CanonicalizeOrLegacy(raw)
-			if err != nil {
-				return fmt.Errorf("failed to canonicalize cart id: %w", err)
-			}
-			legacy = CartIDToLegacy(cid)
-			// Only set a new cookie if we actually generated a brand-new ID (empty input).
-			// For legacy (non-base62) ids we preserve the original text and do not overwrite.
-			if generated && wasBase62 {
-				http.SetCookie(w, &http.Cookie{
-					Name:     "cartid",
-					Value:    cid.String(),
-					Secure:   r.TLS != nil,
-					HttpOnly: true,
-					Path:     "/",
-					Expires:  time.Now().AddDate(0, 0, 14),
-					SameSite: http.SameSiteLaxMode,
-				})
-				w.Header().Set("Set-Cart-Id", cid.String())
-			}
-		}
-		return fn(w, r, legacy)
-	}
-}
-
-func (s *PoolServer) RemoveCartCookie(w http.ResponseWriter, r *http.Request, cartId CartId) error {
-	cartId = NewCartId()
-	http.SetCookie(w, &http.Cookie{
-		Name:     "cartid",
-		Value:    cartId.String(),
-		Path:     "/",
-		Secure:   r.TLS != nil,
-		HttpOnly: true,
-		Expires:  time.Unix(0, 0),
-		SameSite: http.SameSiteLaxMode,
-	})
-	w.WriteHeader(http.StatusOK)
-	return nil
-}
-
-func CartIdHandler(fn func(w http.ResponseWriter, r *http.Request, cartId CartId) error) func(w http.ResponseWriter, r *http.Request) error {
-	return func(w http.ResponseWriter, r *http.Request) error {
-		raw := r.PathValue("id")
-		cid, generated, wasBase62, err := CanonicalizeOrLegacy(raw)
-		if err != nil {
-			return fmt.Errorf("invalid cart id: %w", err)
-		}
-		legacy := CartIDToLegacy(cid)
-		// Only emit Set-Cart-Id header if we produced a brand-new canonical id
-		// AND it is base62 (avoid rewriting legacy textual identifiers).
-		if generated && wasBase62 {
-			w.Header().Set("Set-Cart-Id", cid.String())
-		}
-		return fn(w, r, legacy)
-	}
-}
-
-func (s *PoolServer) Serve() *http.ServeMux {
-	mux := http.NewServeMux()
-	//mux.HandleFunc("/", s.RewritePath)
-	mux.HandleFunc("OPTIONS /", func(w http.ResponseWriter, r *http.Request) {
-		w.Header().Set("Access-Control-Allow-Origin", "*")
-		w.Header().Set("Access-Control-Allow-Methods", "GET, PUT, POST, DELETE")
-		w.Header().Set("Access-Control-Allow-Headers", "Content-Type")
-		w.WriteHeader(http.StatusOK)
-	})
-
-	mux.HandleFunc("GET /", ErrorHandler(CookieCartIdHandler(s.HandleGet)))
-	mux.HandleFunc("GET /add/{sku}", ErrorHandler(CookieCartIdHandler(s.HandleAddSku)))
-	mux.HandleFunc("POST /", ErrorHandler(CookieCartIdHandler(s.HandleAddRequest)))
-	mux.HandleFunc("POST /set", ErrorHandler(CookieCartIdHandler(s.HandleSetCartItems)))
-	mux.HandleFunc("DELETE /{itemId}", ErrorHandler(CookieCartIdHandler(s.HandleDeleteItem)))
-	mux.HandleFunc("PUT /", ErrorHandler(CookieCartIdHandler(s.HandleQuantityChange)))
-	mux.HandleFunc("DELETE /", ErrorHandler(CookieCartIdHandler(s.RemoveCartCookie)))
-	mux.HandleFunc("POST /delivery", ErrorHandler(CookieCartIdHandler(s.HandleSetDelivery)))
-	mux.HandleFunc("DELETE /delivery/{deliveryId}", ErrorHandler(CookieCartIdHandler(s.HandleRemoveDelivery)))
-	mux.HandleFunc("PUT /delivery/{deliveryId}/pickupPoint", ErrorHandler(CookieCartIdHandler(s.HandleSetPickupPoint)))
-	mux.HandleFunc("GET /checkout", ErrorHandler(CookieCartIdHandler(s.HandleCheckout)))
-	mux.HandleFunc("GET /confirmation/{orderId}", ErrorHandler(CookieCartIdHandler(s.HandleConfirmation)))
-
-	mux.HandleFunc("GET /byid/{id}", ErrorHandler(CartIdHandler(s.HandleGet)))
-	mux.HandleFunc("GET /byid/{id}/add/{sku}", ErrorHandler(CartIdHandler(s.HandleAddSku)))
-	mux.HandleFunc("POST /byid/{id}", ErrorHandler(CartIdHandler(s.HandleAddRequest)))
-	mux.HandleFunc("DELETE /byid/{id}/{itemId}", ErrorHandler(CartIdHandler(s.HandleDeleteItem)))
-	mux.HandleFunc("PUT /byid/{id}", ErrorHandler(CartIdHandler(s.HandleQuantityChange)))
-	mux.HandleFunc("POST /byid/{id}/delivery", ErrorHandler(CartIdHandler(s.HandleSetDelivery)))
-	mux.HandleFunc("DELETE /byid/{id}/delivery/{deliveryId}", ErrorHandler(CartIdHandler(s.HandleRemoveDelivery)))
-	mux.HandleFunc("PUT /byid/{id}/delivery/{deliveryId}/pickupPoint", ErrorHandler(CartIdHandler(s.HandleSetPickupPoint)))
-	mux.HandleFunc("GET /byid/{id}/checkout", ErrorHandler(CartIdHandler(s.HandleCheckout)))
-	mux.HandleFunc("GET /byid/{id}/confirmation", ErrorHandler(CartIdHandler(s.HandleConfirmation)))
-
-	return mux
-}

product-fetcher.go

@@ -1,35 +0,0 @@
-package main
-
-import (
-	"encoding/json"
-	"fmt"
-	"net/http"
-
-	"github.com/matst80/slask-finder/pkg/index"
-)
-
-// TODO make this configurable
-func getBaseUrl(country string) string {
-	// if country == "se" {
-	// 	return "http://s10n-se:8080"
-	// }
-	if country == "no" {
-		return "http://s10n-no.s10n:8080"
-	}
-	if country == "se" {
-		return "http://s10n-se.s10n:8080"
-	}
-	return "http://localhost:8082"
-}
-
-func FetchItem(sku string, country string) (*index.DataItem, error) {
-	baseUrl := getBaseUrl(country)
-	res, err := http.Get(fmt.Sprintf("%s/api/by-sku/%s", baseUrl, sku))
-	if err != nil {
-		return nil, err
-	}
-	defer res.Body.Close()
-	var item index.DataItem
-	err = json.NewDecoder(res.Body).Decode(&item)
-	return &item, err
-}