feature/backoffice (#6)

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>
2025-10-16 09:45:58 +02:00
parent 8c2bcf5e75
commit 8682daf481
32 changed files with 907 additions and 164 deletions
--- a/cmd/backoffice/fileserver.go
+++ b/cmd/backoffice/fileserver.go
@@ -0,0 +1,187 @@
+package main
+
+import (
+	"bufio"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"net/http"
+	"os"
+	"path/filepath"
+	"regexp"
+	"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
+}
+
+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, CartFileInfo{
+			ID:       fmt.Sprintf("%d", id),
+			CartId:   cart.CartId(id),
+			Size:     info.Size(),
+			Modified: info.ModTime(),
+			System:   info.Sys(),
+		})
+	}
+	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,
+	})
+}
+
+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,
+			"system":   info.Sys(),
+		},
+	})
+}
--- a/cmd/backoffice/hub.go
+++ b/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"))
+		}
+	}
+}
--- a/cmd/backoffice/main.go
+++ b/cmd/backoffice/main.go
@@ -1,5 +1,149 @@
 package main

-func main() {
-	// Your code here
+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"`
+	System   any         `json:"system"`
+}
+
+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("/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:  10 * 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: %w", 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
 }
--- a/cmd/cart/cart-grain.go
+++ b/cmd/cart/cart-grain.go
@@ -1,272 +0,0 @@
-package main
-
-import (
-	"encoding/json"
-	"fmt"
-	"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"`
-}
-
-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 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"`
-}
-
-type Voucher struct {
-	Code  string                  `json:"code"`
-	Rules []*messages.VoucherRule `json:"rules"`
-	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 _, rule := range v.Rules {
-		expr := rule.GetCondition()
-		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 (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 getInt(data float64, ok bool) (int, error) {
-	if !ok {
-		return 0, fmt.Errorf("invalid type")
-	}
-	return int(data), 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)
-// }
-
-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))
-
-		item.TotalPrice = *rowTotal
-
-		c.TotalPrice.Add(*rowTotal)
-
-		if item.OrgPrice != nil {
-			diff := NewPrice()
-			diff.Add(*item.OrgPrice)
-			diff.Subtract(item.Price)
-			if diff.IncVat > 0 {
-				c.TotalDiscount.Add(*diff)
-			}
-		}
-
-	}
-	for _, delivery := range c.Deliveries {
-		c.TotalPrice.Add(delivery.Price)
-	}
-	for _, voucher := range c.Vouchers {
-		if _, ok := voucher.AppliesTo(c); ok {
-			value := NewPriceFromIncVat(voucher.Value, 25)
-			if c.TotalPrice.IncVat <= value.IncVat {
-				// don't apply discounts to more than the total price
-				continue
-			}
-
-			c.TotalDiscount.Add(*value)
-			c.TotalPrice.Subtract(*value)
-		}
-	}
-}
--- a/cmd/cart/cart_grain_totals_test.go
+++ b/cmd/cart/cart_grain_totals_test.go
@@ -1,48 +0,0 @@
-package main
-
-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)
-	}
-}
--- a/cmd/cart/cart_id.go
+++ b/cmd/cart/cart_id.go
@@ -1,159 +0,0 @@
-package main
-
-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
-}
--- a/cmd/cart/cart_id_test.go
+++ b/cmd/cart/cart_id_test.go
@@ -1,185 +0,0 @@
-package main
-
-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
-}
--- a/cmd/cart/checkout_builder.go
+++ b/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")
 	}
--- a/cmd/cart/main.go
+++ b/cmd/cart/main.go
@@ -13,6 +13,7 @@ import (
 	"time"

 	"git.tornberg.me/go-cart-actor/pkg/actor"
+	"git.tornberg.me/go-cart-actor/pkg/cart"
 	"git.tornberg.me/go-cart-actor/pkg/discovery"
 	messages "git.tornberg.me/go-cart-actor/pkg/messages"
 	"git.tornberg.me/go-cart-actor/pkg/proxy"
@@ -46,7 +47,7 @@ func init() {
 }

 type App struct {
-	pool *actor.SimpleGrainPool[CartGrain]
+	pool *actor.SimpleGrainPool[cart.CartGrain]
 }

 var podIp = os.Getenv("POD_IP")
@@ -98,63 +99,24 @@ type MutationContext struct {
 	VoucherService voucher.Service
 }

+type CartChangeEvent struct {
+	CartId    cart.CartId         `json:"cartId"`
+	Mutations []actor.ApplyResult `json:"mutations"`
+}
+
 func main() {

 	controlPlaneConfig := actor.DefaultServerConfig()

-	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{}
-		}),
-	)
-	diskStorage := actor.NewDiskStorage[CartGrain]("data", reg)
-	poolConfig := actor.GrainPoolConfig[CartGrain]{
+	reg := cart.NewCartMultationRegistry()
+	diskStorage := actor.NewDiskStorage[cart.CartGrain]("data", reg)
+	poolConfig := actor.GrainPoolConfig[cart.CartGrain]{
 		MutationRegistry: reg,
 		Storage:          diskStorage,
-		Spawn: func(id uint64) (actor.Grain[CartGrain], error) {
+		Spawn: func(id uint64) (actor.Grain[cart.CartGrain], error) {
 			grainSpawns.Inc()
-			ret := &CartGrain{
-				lastItemId:     0,
-				lastDeliveryId: 0,
-				Deliveries:     []*CartDelivery{},
-				Id:             CartId(id),
-				Items:          []*CartItem{},
-				TotalPrice:     NewPrice(),
-			}
+			ret := cart.NewCartGrain(id, time.Now())
 			// Set baseline lastChange at spawn; replay may update it to last event timestamp.
-			ret.lastChange = time.Now()
-			ret.lastAccess = time.Now()

 			err := diskStorage.LoadEvents(id, ret)

@@ -181,17 +143,22 @@ func main() {
 		fmt.Errorf("failed to connect to RabbitMQ: %w", err)
 	}

-	amqpListener := actor.NewAmqpListener(conn)
+	amqpListener := actor.NewAmqpListener(conn, func(id uint64, msg []actor.ApplyResult) (any, error) {
+		return &CartChangeEvent{
+			CartId:    cart.CartId(id),
+			Mutations: msg,
+		}, nil
+	})
 	amqpListener.DefineTopics()
 	pool.AddListener(amqpListener)

-	grpcSrv, err := actor.NewControlServer[*CartGrain](controlPlaneConfig, pool)
+	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)
+	// go diskStorage.SaveLoop(10 * time.Second)

 	go func(hw discovery.Discovery) {
 		if hw == nil {
@@ -282,14 +249,14 @@ func main() {
 				w.Write([]byte("no cart id to checkout is empty"))
 				return
 			}
-			parsed, ok := ParseCartId(cookie.Value)
+			parsed, ok := cart.ParseCartId(cookie.Value)
 			if !ok {
 				w.WriteHeader(http.StatusBadRequest)
 				w.Write([]byte("invalid cart id format"))
 				return
 			}
 			cartId := parsed
-			syncedServer.ProxyHandler(func(w http.ResponseWriter, r *http.Request, cartId CartId) error {
+			syncedServer.ProxyHandler(func(w http.ResponseWriter, r *http.Request, cartId cart.CartId) error {
 				order, err = syncedServer.CreateOrUpdateCheckout(r.Host, cartId)
 				if err != nil {
 					return err
@@ -443,7 +410,7 @@ func triggerOrderCompleted(syncedServer *PoolServer, order *CheckoutOrder) error
 		OrderId: order.ID,
 		Status:  order.Status,
 	}
-	cid, ok := ParseCartId(order.MerchantReference1)
+	cid, ok := cart.ParseCartId(order.MerchantReference1)
 	if !ok {
 		return fmt.Errorf("invalid cart id in order reference: %s", order.MerchantReference1)
 	}
--- a/cmd/cart/mutation_add_item.go
+++ b/cmd/cart/mutation_add_item.go
@@ -1,91 +0,0 @@
-package main
-
-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)
-	}
-
-	// Fast path: merge with existing item having same SKU
-	if existing, found := g.FindItemWithSku(m.Sku); found {
-		if existing.StoreId == m.StoreId {
-			existing.Quantity += int(m.Quantity)
-			existing.Stock = StockStatus(m.Stock)
-			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,
-		},
-
-		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)
-}
--- a/cmd/cart/mutation_add_voucher.go
+++ b/cmd/cart/mutation_add_voucher.go
@@ -1,64 +0,0 @@
-package main
-
-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,
-		Code:  m.Code,
-		Rules: m.VoucherRules,
-		Value: m.Value,
-	})
-	g.UpdateTotals()
-	return nil
-}
--- a/cmd/cart/mutation_change_quantity.go
+++ b/cmd/cart/mutation_change_quantity.go
@@ -1,54 +0,0 @@
-package main
-
-import (
-	"fmt"
-
-	messages "git.tornberg.me/go-cart-actor/pkg/messages"
-)
-
-// mutation_change_quantity.go
-//
-// Registers the ChangeQuantity mutation.
-//
-// Behavior:
-//   - Locates an item by its cart-local line item Id (not source item_id).
-//   - If requested quantity <= 0 the line is removed.
-//   - Otherwise the line's Quantity field is updated.
-//   - Totals are recalculated (WithTotals).
-//
-// Error handling:
-//   - Returns an error if the item Id is not found.
-//   - Returns an error if payload is nil (defensive).
-//
-// Concurrency:
-//   - Uses the grain's RW-safe mutation pattern: we mutate in place under
-//     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 ChangeQuantity(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 == uint32(m.Id) {
-			foundIndex = i
-			break
-		}
-	}
-	if foundIndex == -1 {
-		return fmt.Errorf("ChangeQuantity: item id %d not found", m.Id)
-	}
-
-	if m.Quantity <= 0 {
-		// Remove the item
-		g.Items = append(g.Items[:foundIndex], g.Items[foundIndex+1:]...)
-		return nil
-	}
-
-	g.Items[foundIndex].Quantity = int(m.Quantity)
-	g.UpdateTotals()
-	return nil
-}
--- a/cmd/cart/mutation_initialize_checkout.go
+++ b/cmd/cart/mutation_initialize_checkout.go
@@ -1,44 +0,0 @@
-package main
-
-import (
-	"fmt"
-
-	messages "git.tornberg.me/go-cart-actor/pkg/messages"
-)
-
-// mutation_initialize_checkout.go
-//
-// Registers the InitializeCheckout mutation.
-// This mutation is invoked AFTER an external Klarna checkout session
-// has been successfully created or updated. It persists the Klarna
-// order reference / status and marks the cart as having a payment in progress.
-//
-// Behavior:
-//   - Sets OrderReference to the Klarna order ID (overwriting if already set).
-//   - Sets PaymentStatus to the current Klarna status.
-//   - Sets / updates PaymentInProgress flag.
-//   - Does NOT alter pricing or line items (so no totals recalculation).
-//
-// Validation:
-//   - Returns an error if payload is nil.
-//   - Returns an error if orderId is empty (integrity guard).
-//
-// Concurrency:
-//   - Relies on upstream mutation serialization for a single grain. If
-//     parallel checkout attempts are possible, add higher-level guards
-//     (e.g. reject if PaymentInProgress already true unless reusing
-//     the same OrderReference).
-
-func InitializeCheckout(g *CartGrain, m *messages.InitializeCheckout) error {
-	if m == nil {
-		return fmt.Errorf("InitializeCheckout: nil payload")
-	}
-	if m.OrderId == "" {
-		return fmt.Errorf("InitializeCheckout: missing orderId")
-	}
-
-	g.OrderReference = m.OrderId
-	g.PaymentStatus = m.Status
-	g.PaymentInProgress = m.PaymentInProgress
-	return nil
-}
--- a/cmd/cart/mutation_order_created.go
+++ b/cmd/cart/mutation_order_created.go
@@ -1,48 +0,0 @@
-package main
-
-import (
-	"fmt"
-
-	messages "git.tornberg.me/go-cart-actor/pkg/messages"
-)
-
-// mutation_order_created.go
-//
-// Registers the OrderCreated mutation.
-//
-// This mutation represents the completion (or state transition) of an order
-// initiated earlier via InitializeCheckout / external Klarna processing.
-// It finalizes (or updates) the cart's order metadata.
-//
-// Behavior:
-//   - Validates payload non-nil and OrderId not empty.
-//   - Sets (or overwrites) OrderReference with the provided OrderId.
-//   - Sets PaymentStatus from payload.Status.
-//   - Marks PaymentInProgress = false (checkout flow finished / acknowledged).
-//   - Does NOT adjust monetary totals (no WithTotals()).
-//
-// Notes / Future Extensions:
-//   - If multiple order completion events can arrive (e.g., retries / webhook
-//     replays), this handler is idempotent: it simply overwrites fields.
-//   - If you need to guard against conflicting order IDs, add a check:
-//     if g.OrderReference != "" && g.OrderReference != m.OrderId { ... }
-//   - Add audit logging or metrics here if required.
-//
-// Concurrency:
-//   - 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 OrderCreated(g *CartGrain, m *messages.OrderCreated) error {
-	if m == nil {
-		return fmt.Errorf("OrderCreated: nil payload")
-	}
-	if m.OrderId == "" {
-		return fmt.Errorf("OrderCreated: missing orderId")
-	}
-
-	g.OrderReference = m.OrderId
-	g.PaymentStatus = m.Status
-	g.PaymentInProgress = false
-	return nil
-}
--- a/cmd/cart/mutation_remove_delivery.go
+++ b/cmd/cart/mutation_remove_delivery.go
@@ -1,49 +0,0 @@
-package main
-
-import (
-	"fmt"
-
-	messages "git.tornberg.me/go-cart-actor/pkg/messages"
-)
-
-// mutation_remove_delivery.go
-//
-// Registers the RemoveDelivery mutation.
-//
-// Behavior:
-//   - Removes the delivery entry whose Id == payload.Id.
-//   - If not found, returns an error.
-//   - Cart totals are recalculated (WithTotals) after removal.
-//   - Items previously associated with that delivery simply become "without delivery";
-//     subsequent delivery mutations can reassign them.
-//
-// Differences vs legacy:
-//   - Legacy logic decremented TotalPrice explicitly before recalculating.
-//     Here we rely solely on UpdateTotals() to recompute from remaining
-//     deliveries and items (simpler / single source of truth).
-//
-// Future considerations:
-//   - If delivery pricing logic changes (e.g., dynamic taxes per delivery),
-//     UpdateTotals() may need enhancement to incorporate delivery tax properly.
-
-func RemoveDelivery(g *CartGrain, m *messages.RemoveDelivery) error {
-	if m == nil {
-		return fmt.Errorf("RemoveDelivery: nil payload")
-	}
-	targetID := uint32(m.Id)
-	index := -1
-	for i, d := range g.Deliveries {
-		if d.Id == targetID {
-			index = i
-			break
-		}
-	}
-	if index == -1 {
-		return fmt.Errorf("RemoveDelivery: delivery id %d not found", m.Id)
-	}
-
-	// Remove delivery (order not preserved beyond necessity)
-	g.Deliveries = append(g.Deliveries[:index], g.Deliveries[index+1:]...)
-	g.UpdateTotals()
-	return nil
-}
--- a/cmd/cart/mutation_remove_item.go
+++ b/cmd/cart/mutation_remove_item.go
@@ -1,45 +0,0 @@
-package main
-
-import (
-	"fmt"
-
-	messages "git.tornberg.me/go-cart-actor/pkg/messages"
-)
-
-// mutation_remove_item.go
-//
-// Registers the RemoveItem mutation.
-//
-// Behavior:
-//   - Removes the cart line whose local cart line Id == payload.Id
-//   - If no such line exists returns an error
-//   - Recalculates cart totals (WithTotals)
-//
-// Notes:
-//   - This removes only the line item; any deliveries referencing the removed
-//     item are NOT automatically adjusted (mirrors prior logic). If future
-//     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 RemoveItem(g *CartGrain, m *messages.RemoveItem) error {
-	if m == nil {
-		return fmt.Errorf("RemoveItem: nil payload")
-	}
-	targetID := uint32(m.Id)
-
-	index := -1
-	for i, it := range g.Items {
-		if it.Id == targetID {
-			index = i
-			break
-		}
-	}
-	if index == -1 {
-		return fmt.Errorf("RemoveItem: item id %d not found", m.Id)
-	}
-
-	g.Items = append(g.Items[:index], g.Items[index+1:]...)
-	g.UpdateTotals()
-	return nil
-}
--- a/cmd/cart/mutation_set_delivery.go
+++ b/cmd/cart/mutation_set_delivery.go
@@ -1,96 +0,0 @@
-package main
-
-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
-}
--- a/cmd/cart/mutation_set_pickup_point.go
+++ b/cmd/cart/mutation_set_pickup_point.go
@@ -1,62 +0,0 @@
-package main
-
-import (
-	"fmt"
-
-	messages "git.tornberg.me/go-cart-actor/pkg/messages"
-)
-
-// mutation_set_pickup_point.go
-//
-// Registers the SetPickupPoint mutation using the generic mutation registry.
-//
-// Semantics (mirrors original switch-based implementation):
-//   - Locate the delivery with Id == payload.DeliveryId
-//   - Set (or overwrite) its PickupPoint with the provided data
-//   - Does NOT alter pricing or taxes (so no totals recalculation required)
-//
-// Validation / Error Handling:
-//   - If payload is nil -> error
-//   - If DeliveryId not found -> error
-//
-// Concurrency:
-//   - Relies on the existing expectation that higher-level mutation routing
-//     serializes Apply() calls per grain; if stricter guarantees are needed,
-//     a delivery-level lock could be introduced later.
-//
-// Future Extensions:
-//   - 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 SetPickupPoint(g *CartGrain, m *messages.SetPickupPoint) error {
-	if m == nil {
-		return fmt.Errorf("SetPickupPoint: nil payload")
-	}
-
-	for _, d := range g.Deliveries {
-		if d.Id == uint32(m.DeliveryId) {
-			d.PickupPoint = &messages.PickupPoint{
-				Id:      m.Id,
-				Name:    m.Name,
-				Address: m.Address,
-				City:    m.City,
-				Zip:     m.Zip,
-				Country: m.Country,
-			}
-			return nil
-		}
-	}
-	return fmt.Errorf("SetPickupPoint: delivery id %d not found", m.DeliveryId)
-}
-
-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
-}
--- a/cmd/cart/pool-server.go
+++ b/cmd/cart/pool-server.go
@@ -11,18 +11,19 @@ import (
 	"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"
 )

 type PoolServer struct {
-	actor.GrainPool[*CartGrain]
+	actor.GrainPool[*cart.CartGrain]
 	pod_name     string
 	klarnaClient *KlarnaClient
 }

-func NewPoolServer(pool actor.GrainPool[*CartGrain], pod_name string, klarnaClient *KlarnaClient) *PoolServer {
+func NewPoolServer(pool actor.GrainPool[*cart.CartGrain], pod_name string, klarnaClient *KlarnaClient) *PoolServer {
 	return &PoolServer{
 		GrainPool:    pool,
 		pod_name:     pod_name,
@@ -30,11 +31,11 @@ func NewPoolServer(pool actor.GrainPool[*CartGrain], pod_name string, klarnaClie
 	}
 }

-func (s *PoolServer) ApplyLocal(id CartId, mutation ...proto.Message) (*actor.MutationResult[*CartGrain], error) {
+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 CartId) error {
+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
@@ -43,7 +44,7 @@ func (s *PoolServer) GetCartHandler(w http.ResponseWriter, r *http.Request, id C
 	return s.WriteResult(w, grain)
 }

-func (s *PoolServer) AddSkuToCartHandler(w http.ResponseWriter, r *http.Request, id CartId) error {
+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 {
@@ -73,7 +74,7 @@ func (s *PoolServer) WriteResult(w http.ResponseWriter, result any) error {
 	return err
 }

-func (s *PoolServer) DeleteItemHandler(w http.ResponseWriter, r *http.Request, id CartId) error {
+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)
@@ -93,7 +94,7 @@ type SetDeliveryRequest struct {
 	PickupPoint *messages.PickupPoint `json:"pickupPoint,omitempty"`
 }

-func (s *PoolServer) SetDeliveryHandler(w http.ResponseWriter, r *http.Request, id CartId) error {
+func (s *PoolServer) SetDeliveryHandler(w http.ResponseWriter, r *http.Request, id cart.CartId) error {

 	delivery := SetDeliveryRequest{}
 	err := json.NewDecoder(r.Body).Decode(&delivery)
@@ -111,7 +112,7 @@ func (s *PoolServer) SetDeliveryHandler(w http.ResponseWriter, r *http.Request,
 	return s.WriteResult(w, data)
 }

-func (s *PoolServer) SetPickupPointHandler(w http.ResponseWriter, r *http.Request, id CartId) error {
+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)
@@ -138,7 +139,7 @@ func (s *PoolServer) SetPickupPointHandler(w http.ResponseWriter, r *http.Reques
 	return s.WriteResult(w, reply)
 }

-func (s *PoolServer) RemoveDeliveryHandler(w http.ResponseWriter, r *http.Request, id CartId) error {
+func (s *PoolServer) RemoveDeliveryHandler(w http.ResponseWriter, r *http.Request, id cart.CartId) error {

 	deliveryIdString := r.PathValue("deliveryId")
 	deliveryId, err := strconv.Atoi(deliveryIdString)
@@ -152,7 +153,7 @@ func (s *PoolServer) RemoveDeliveryHandler(w http.ResponseWriter, r *http.Reques
 	return s.WriteResult(w, reply)
 }

-func (s *PoolServer) QuantityChangeHandler(w http.ResponseWriter, r *http.Request, id CartId) error {
+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 {
@@ -197,7 +198,7 @@ func getMultipleAddMessages(items []Item, country string) []proto.Message {
 	return msgs
 }

-func (s *PoolServer) SetCartItemsHandler(w http.ResponseWriter, r *http.Request, id CartId) error {
+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 {
@@ -215,7 +216,7 @@ func (s *PoolServer) SetCartItemsHandler(w http.ResponseWriter, r *http.Request,
 	return s.WriteResult(w, reply)
 }

-func (s *PoolServer) AddMultipleItemHandler(w http.ResponseWriter, r *http.Request, id CartId) error {
+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 {
@@ -236,7 +237,7 @@ type AddRequest struct {
 	StoreId  *string `json:"storeId"`
 }

-func (s *PoolServer) AddSkuRequestHandler(w http.ResponseWriter, r *http.Request, id CartId) error {
+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 {
@@ -287,7 +288,7 @@ func getLocale(country string) string {
 	return "sv-se"
 }

-func (s *PoolServer) CreateOrUpdateCheckout(host string, id CartId) (*CheckoutOrder, error) {
+func (s *PoolServer) CreateOrUpdateCheckout(host string, id cart.CartId) (*CheckoutOrder, error) {
 	country := getCountryFromHost(host)
 	meta := &CheckoutMeta{
 		Terms:        fmt.Sprintf("https://%s/terms", host),
@@ -319,7 +320,7 @@ func (s *PoolServer) CreateOrUpdateCheckout(host string, id CartId) (*CheckoutOr
 	}
 }

-func (s *PoolServer) ApplyCheckoutStarted(klarnaOrder *CheckoutOrder, id CartId) (*actor.MutationResult[*CartGrain], error) {
+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,
@@ -341,12 +342,12 @@ func (s *PoolServer) ApplyCheckoutStarted(klarnaOrder *CheckoutOrder, id CartId)
 // }
 //

-func CookieCartIdHandler(fn func(cartId CartId, w http.ResponseWriter, r *http.Request) error) func(w http.ResponseWriter, r *http.Request) {
+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 CartId
+		var id cart.CartId
 		cookie, err := r.Cookie("cartid")
 		if err != nil || cookie.Value == "" {
-			id = MustNewCartId()
+			id = cart.MustNewCartId()
 			http.SetCookie(w, &http.Cookie{
 				Name:     "cartid",
 				Value:    id.String(),
@@ -358,9 +359,9 @@ func CookieCartIdHandler(fn func(cartId CartId, w http.ResponseWriter, r *http.R
 			})
 			w.Header().Set("Set-Cart-Id", id.String())
 		} else {
-			parsed, ok := ParseCartId(cookie.Value)
+			parsed, ok := cart.ParseCartId(cookie.Value)
 			if !ok {
-				id = MustNewCartId()
+				id = cart.MustNewCartId()
 				http.SetCookie(w, &http.Cookie{
 					Name:     "cartid",
 					Value:    id.String(),
@@ -388,7 +389,7 @@ func CookieCartIdHandler(fn func(cartId CartId, w http.ResponseWriter, r *http.R

 // Removed leftover legacy block after CookieCartIdHandler (obsolete code referencing cid/legacy)

-func (s *PoolServer) RemoveCartCookie(w http.ResponseWriter, r *http.Request, cartId CartId) error {
+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",
@@ -403,17 +404,17 @@ func (s *PoolServer) RemoveCartCookie(w http.ResponseWriter, r *http.Request, ca
 	return nil
 }

-func CartIdHandler(fn func(cartId CartId, w http.ResponseWriter, r *http.Request) error) func(w http.ResponseWriter, r *http.Request) {
+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 CartId
+		var id cart.CartId
 		raw := r.PathValue("id")
 		// If no id supplied, generate a new one
 		if raw == "" {
-			id := MustNewCartId()
+			id := cart.MustNewCartId()
 			w.Header().Set("Set-Cart-Id", id.String())
 		} else {
 			// Parse base62 cart id
-			if parsedId, ok := ParseCartId(raw); !ok {
+			if parsedId, ok := cart.ParseCartId(raw); !ok {
 				w.WriteHeader(http.StatusBadRequest)
 				w.Write([]byte("cart id is invalid"))
 				return
@@ -431,8 +432,8 @@ func CartIdHandler(fn func(cartId CartId, w http.ResponseWriter, r *http.Request
 	}
 }

-func (s *PoolServer) ProxyHandler(fn func(w http.ResponseWriter, r *http.Request, cartId CartId) error) func(cartId CartId, w http.ResponseWriter, r *http.Request) error {
-	return func(cartId CartId, w http.ResponseWriter, r *http.Request) 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 {
 			handled, err := ownerHost.Proxy(uint64(cartId), w, r)
 			if err == nil && handled {
@@ -449,7 +450,7 @@ type AddVoucherRequest struct {
 	VoucherCode string `json:"code"`
 }

-func (s *PoolServer) AddVoucherHandler(w http.ResponseWriter, r *http.Request, cartId CartId) error {
+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{}
@@ -469,7 +470,7 @@ func (s *PoolServer) AddVoucherHandler(w http.ResponseWriter, r *http.Request, c
 	return nil
 }

-func (s *PoolServer) RemoveVoucherHandler(w http.ResponseWriter, r *http.Request, cartId CartId) error {
+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)
--- a/cmd/cart/price.go
+++ b/cmd/cart/price.go
@@ -1,131 +0,0 @@
-package main
-
-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
-}
--- a/cmd/cart/product-fetcher.go
+++ b/cmd/cart/product-fetcher.go
@@ -7,6 +7,7 @@ import (
 	"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"
 )
@@ -53,19 +54,19 @@ func ToItemAddMessage(item *index.DataItem, storeId *string, qty int, country st
 		return nil
 	}

-	stock := StockStatus(0)
+	stock := cart.StockStatus(0)
 	centralStockValue, ok := item.GetStringFieldValue(3)
 	if storeId == nil {
 		if ok {
 			pureNumber := strings.Replace(centralStockValue, "+", "", -1)
 			if centralStock, err := strconv.ParseInt(pureNumber, 10, 64); err == nil {
-				stock = StockStatus(centralStock)
+				stock = cart.StockStatus(centralStock)
 			}
 		}
 	} else {
 		storeStock, ok := item.Stock.GetStock()[*storeId]
 		if ok {
-			stock = StockStatus(storeStock)
+			stock = cart.StockStatus(storeStock)
 		}
 	}

@@ -119,3 +120,10 @@ func getTax(articleType string) int32 {
 		return 2500
 	}
 }
+
+func getInt(data float64, ok bool) (int, error) {
+	if !ok {
+		return 0, fmt.Errorf("invalid type")
+	}
+	return int(data), nil
+}