public BasketItem(int productId, int quantity, Pounds priceInPounds)
{
Contract.Require(productId > 0, ErrorMessage.ProductIdGreaterThanZero);
Contract.Require(quantity > 0, ErrorMessage.QuantityGreaterThanZero);
Contract.Require(priceInPounds != null, ErrorMessage.PriceRequired);
Contract.Require(!priceInPounds.IsZero, ErrorMessage.PriceCannotBeZero);
ProductId = productId;
Quantity = quantity;
PriceInPounds = priceInPounds;
}
public virtual BasketItem AddItem(int productId, int quantity, Pounds priceInPounds)
{
BasketItem basketItem;
bool itemAlreadyExists = _items.Any(i => i.ProductId == productId);
if (!itemAlreadyExists)
{
basketItem = new BasketItem(productId, quantity, priceInPounds);
_items.Add(basketItem);
}
else
{
basketItem = _items.First(i => i.ProductId == productId);
int newQuantity = basketItem.Quantity + quantity;
basketItem.ChangeQuantity(newQuantity);
}
return(basketItem);
}