all the refactor

cmd/inventory/stockhandler.go

@@ -6,6 +6,7 @@ import (
 	"sync"
 
 	"git.k6n.net/mats/go-redis-inventory/pkg/inventory"
+	"git.k6n.net/mats/platform/rabbit"
 	"git.k6n.net/mats/slask-finder/pkg/types"
 	"github.com/redis/go-redis/v9"
 )
@@ -15,12 +16,17 @@ type StockHandler struct {
 	ctx                 context.Context
 	svc                 inventory.RedisInventoryService
 	MainStockLocationID inventory.LocationID
+
+	// Bus producer config. conn is nil when RABBIT_HOST is unset (no bus); the
+	// handler still updates Redis and just skips emitting.
+	conn    *rabbit.Conn
+	country string
+	low     int64
 }
 
 func (s *StockHandler) HandleItem(item types.Item, wg *sync.WaitGroup) {
 	wg.Go(func() {
 		ctx := s.ctx
-		pipe := s.rdb.Pipeline()
 		centralStock, ok := item.GetNumberFieldValue("inStock")
 		if !ok {
 			centralStock = 0
@@ -28,16 +34,17 @@ func (s *StockHandler) HandleItem(item types.Item, wg *sync.WaitGroup) {
 		sku, ok := item.GetStringFieldValue("sku")
 		if !ok {
 			log.Printf("unable to parse central stock for item: sku missing")
-			centralStock = 0
-		} else {
-			s.svc.UpdateInventory(ctx, pipe, inventory.SKU(sku), s.MainStockLocationID, int64(centralStock))
+			return
 		}
-		// for id, value := range item.GetStock() {
-		// 	s.svc.UpdateInventory(ctx, pipe, inventory.SKU(sku), inventory.LocationID(id), int64(value))
-		// }
-		_, err := pipe.Exec(ctx)
-		if err != nil {
+		// One linear pass: write the authoritative quantity, then derive and
+		// emit the level crossing from the same value. No Redis pub/sub
+		// round-trip — Redis stays the internal store, the bus carries levels.
+		pipe := s.rdb.Pipeline()
+		s.svc.UpdateInventory(ctx, pipe, inventory.SKU(sku), s.MainStockLocationID, int64(centralStock))
+		if _, err := pipe.Exec(ctx); err != nil {
 			log.Printf("unable to update stock: %v", err)
+			return
 		}
+		emitLevelIfChanged(ctx, s.rdb, s.conn, s.country, s.low, sku, string(s.MainStockLocationID), int64(centralStock))
 	})
 }