Add order items

internal/mappers/order_mapper.go

@@ -70,8 +70,23 @@ func OrderEntityToResponse(order *entities.Order) *models.OrderResponse {
 	// Map order items
 	if order.OrderItems != nil {
 		response.OrderItems = make([]models.OrderItemResponse, len(order.OrderItems))
+
+		// Build map of paid quantities per order item from payments
+		paidQtyByOrderItem := map[uuid.UUID]int{}
+		if order.Payments != nil {
+			for _, p := range order.Payments {
+				for _, poi := range p.PaymentOrderItems {
+					paidQtyByOrderItem[poi.OrderItemID] += poi.Quantity
+				}
+			}
+		}
+
 		for i, item := range order.OrderItems {
-			response.OrderItems[i] = *OrderItemEntityToResponse(&item)
+			resp := OrderItemEntityToResponse(&item)
+			if resp != nil {
+				resp.PaidQuantity = paidQtyByOrderItem[item.ID]
+				response.OrderItems[i] = *resp
+			}
 		}
 	}