feat: add printer types

internal/processor/order_processor.go

@@ -568,16 +568,10 @@ func (p *OrderProcessorImpl) AddToOrder(ctx context.Context, orderID uuid.UUID,
 		return nil, fmt.Errorf("failed to update order: %w", err)
 	}
 
-	var addedItemResponses []models.OrderItemResponse
 	for _, orderItem := range addedOrderItems {
 		if err := p.orderItemRepo.Create(ctx, orderItem); err != nil {
 			return nil, fmt.Errorf("failed to create order item: %w", err)
 		}
-
-		itemResponse := mappers.OrderItemEntityToResponse(orderItem, order.OutletID)
-		if itemResponse != nil {
-			addedItemResponses = append(addedItemResponses, *itemResponse)
-		}
 	}
 
 	orderWithRelations, err := p.orderRepo.GetWithRelations(ctx, orderID)
@@ -585,6 +579,10 @@ func (p *OrderProcessorImpl) AddToOrder(ctx context.Context, orderID uuid.UUID,
 		return nil, fmt.Errorf("failed to retrieve updated order: %w", err)
 	}
 
+	// The items just created carry no product, so take them from the reloaded order: the
+	// POS prints added items from this response and needs their name and printers.
+	addedItemResponses := addedItemsFromOrder(addedOrderItems, orderWithRelations)
+
 	updatedOrderResponse := mappers.OrderEntityToResponse(orderWithRelations)
 	p.attachEarnings(ctx, updatedOrderResponse)
 
@@ -596,6 +594,26 @@ func (p *OrderProcessorImpl) AddToOrder(ctx context.Context, orderID uuid.UUID,
 	}, nil
 }
 
+// addedItemsFromOrder maps the added items in the order they were requested, using their
+// copies in the reloaded order, which have the product and its outlet prices loaded.
+func addedItemsFromOrder(added []*entities.OrderItem, order *entities.Order) []models.OrderItemResponse {
+	reloaded := make(map[uuid.UUID]*entities.OrderItem, len(order.OrderItems))
+	for i := range order.OrderItems {
+		reloaded[order.OrderItems[i].ID] = &order.OrderItems[i]
+	}
+
+	var responses []models.OrderItemResponse
+	for _, item := range added {
+		if loaded, ok := reloaded[item.ID]; ok {
+			item = loaded
+		}
+		if response := mappers.OrderItemEntityToResponse(item, order.OutletID); response != nil {
+			responses = append(responses, *response)
+		}
+	}
+	return responses
+}
+
 func (p *OrderProcessorImpl) UpdateOrder(ctx context.Context, id uuid.UUID, req *models.UpdateOrderRequest) (*models.OrderResponse, error) {
 	// Get existing order
 	order, err := p.orderRepo.GetByID(ctx, id)