private decimal AddItem(Order order) { string productCode = _validate.ValidateEmptyInput("Select a Bubble Tea from above table by Product Id"); int id = Int32.Parse(productCode); int quantity = _validate.ValidateQuantity("Enter quantity for this item"); Product product = _productBL.GetProductById(id); //To-Do check enough inventory Item inventory = _inventoryBL.GetInventory(product); _orderBL.AddOrderItem(order, product, new Item(quantity)); //To-Do update inventory int newQuantity = inventory.Quantity - quantity; _inventoryBL.UpdateInventory(inventory, newQuantity); Console.WriteLine($"{quantity} {product.Name} is added"); return //product.Price * quantity; (_orderBL.GetTotal(product.Id, quantity)); }