handle limited quantity

pkg/cart/mutation_add_item.go

@@ -38,16 +38,24 @@ func AddItem(g *CartGrain, m *messages.AddItem) error {
 		if !sameStore {
 			continue
 		}
-		existing.Quantity += int(m.Quantity)
+		if m.ReservationEndTime != nil {
+			t := m.ReservationEndTime.AsTime()
+			if existing.ReservationEndTime == nil || existing.ReservationEndTime.Before(m.ReservationEndTime.AsTime()) {
+				existing.ReservationEndTime = &t
+				existing.Quantity = int(m.Quantity)
+			} else {
+				existing.ReservationEndTime = &t
+			}
+
+		} else {
+			existing.Quantity += int(m.Quantity)
+		}
 		existing.Stock = uint16(m.Stock)
 		// If existing had nil store but new has one, adopt it.
 		if existing.StoreId == nil && m.StoreId != nil {
 			existing.StoreId = m.StoreId
 		}
-		if m.ReservationEndTime != nil {
-			t := m.ReservationEndTime.AsTime()
-			existing.ReservationEndTime = &t
-		}
+
 		return nil
 	}