From b0907aee41c822217e4f705dc8e8f250da10011c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Mats=20T=C3=B6rnberg?= <mats@tornberg.me>
Date: Tue, 25 Nov 2025 20:27:04 +0100
Subject: [PATCH] update

---
 cmd/cart/pool-server.go | 16 ++++++++++++++--
 pkg/cart/cart-grain.go  | 18 ++++++++++++++----
 2 files changed, 28 insertions(+), 6 deletions(-)

diff --git a/cmd/cart/pool-server.go b/cmd/cart/pool-server.go
index 8f9afb3..36bc93a 100644
--- a/cmd/cart/pool-server.go
+++ b/cmd/cart/pool-server.go
@@ -19,6 +19,7 @@ import (
 	"github.com/matst80/go-redis-inventory/pkg/inventory"
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/client_golang/prometheus/promauto"
+	"github.com/redis/go-redis/v9"
 	"go.opentelemetry.io/contrib/bridges/otelslog"
 	"go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp"
 	"google.golang.org/protobuf/types/known/anypb"
@@ -47,13 +48,24 @@ type PoolServer struct {
 	inventoryService inventory.InventoryService
 }
 
-func NewPoolServer(pool actor.GrainPool[*cart.CartGrain], pod_name string, klarnaClient *KlarnaClient, inventoryService inventory.InventoryService) *PoolServer {
-	return &PoolServer{
+func NewPoolServer(pool actor.GrainPool[*cart.CartGrain], pod_name string, klarnaClient *KlarnaClient, inventoryService inventory.InventoryService, inventoryRedisClient *redis.Client) *PoolServer {
+	srv := &PoolServer{
 		GrainPool:        pool,
 		pod_name:         pod_name,
 		klarnaClient:     klarnaClient,
 		inventoryService: inventoryService,
 	}
+	inventory.NewInventoryChangeListener(inventoryRedisClient, func(ctx context.Context, sku inventory.SKU, locationID inventory.LocationID) {
+		qty, err := inventoryService.GetInventory(ctx, sku, locationID)
+		if err != nil {
+			log.Printf("error fetching inventory for sku %s at location %s: %v", sku, locationID, err)
+		}
+		srv.GrainPool.GetPubSub().Publish(actor.Event{
+			Topic:   fmt.Sprintf("inventory:%s:%s", sku, locationID),
+			Payload: qty,
+		})
+	})
+	return srv
 }
 
 func (s *PoolServer) ApplyLocal(ctx context.Context, id cart.CartId, mutation ...proto.Message) (*actor.MutationResult[*cart.CartGrain], error) {
diff --git a/pkg/cart/cart-grain.go b/pkg/cart/cart-grain.go
index 050cf57..7f3d96e 100644
--- a/pkg/cart/cart-grain.go
+++ b/pkg/cart/cart-grain.go
@@ -2,6 +2,7 @@ package cart
 
 import (
 	"encoding/json"
+	"log"
 	"slices"
 	"strings"
 	"sync"
@@ -234,12 +235,21 @@ func (c *CartGrain) Notify(event actor.Event) {
 	defer c.mu.Unlock()
 	// Example: if event is inventory change for a SKU in the cart
 	if strings.HasPrefix(event.Topic, "inventory:") {
-		sku := strings.TrimPrefix(event.Topic, "inventory:")
+		skuAndLocationId := strings.TrimPrefix(event.Topic, "inventory:")
+		parts := strings.Split(skuAndLocationId, ":")
+		if len(parts) != 2 {
+			return
+		}
+		sku := parts[0]
+		locationId := parts[1]
+		log.Printf("cart grain got inventory update: %s", event.Topic)
 		for _, item := range c.Items {
-			if item.Sku == sku {
+			if item.Sku == sku && item.StoreId != nil && *item.StoreId == locationId {
 				// Update stock status based on payload, e.g., if payload is bool available
-				if available, ok := event.Payload.(bool); ok {
-					if available {
+
+				if quantity, ok := event.Payload.(int64); ok {
+					log.Printf("cart grain got item stock update %d", quantity)
+					if quantity > 0 {
 						item.Stock = 1 // assuming 1 is in stock
 					} else {
 						item.Stock = 0 // out of stock