learn viedo delete and add permison

backend/order/views.py

@@ -29,22 +29,23 @@ class CartItemViews(APIView):
     serializer_class = OrderItemSerailzier
     def post(self, request, pk):
         product_variant = get_object_or_404(ProductVariant, pk=pk)
+        response = 'محصول با موفقیت به سبد خرید اضافه شد'
+        quantity = request.data.get('quantity', 1)
+        if product_variant.in_stock < quantity:
+            quantity = product_variant.in_stock
+            response = 'تعداد درخواستی بیشتر از موجودی محصول میباشد'
 
-        cart_order, created = OrderModel.objects.get_or_create(
-            user=request.user,
-            status='CART'
-        )
-        order_item, created = OrderItemModel.objects.get_or_create(
-            order=cart_order,
-            product=product_variant,
-            defaults={'quantity': request.data.get('quantity', 1)}
-        )
+        cart_order, created = OrderModel.objects.get_or_create(user=request.user, status='CART')
+        order_item, created = OrderItemModel.objects.get_or_create(order=cart_order, product=product_variant, defaults={'quantity': quantity})
 
-        if not created:  
-            order_item.quantity = request.data.get('quantity', 1)
+        if not created and order_item.quantity:  
+            order_item.quantity = quantity
             order_item.save()
-
-        return Response({'detail': f'تعداد ایتم {product_variant.product.name} به {request.data.get('quantity', 1)} تغییر کرد'}, status=status.HTTP_202_ACCEPTED)
+        if not order_item.quantity:
+            order_item.delete()
+        return Response({'detail': response, 'count': quantity}, status=status.HTTP_202_ACCEPTED)
+    
+    
     def delete(self, request, pk):
         product_variant = get_object_or_404(ProductVariant, pk=pk)