/// <summary>
/// Adds new item to the cart. If the product exists increases its quantity
/// </summary>
/// <param name="productsApi">Products Api Gateway</param>
/// <param name="newCartItem">NewCartItem to be added</param>
internal void AddToCart(IProductsApiConnector productsApi, NewCartItem newCartItem)
{
if (productsApi == null)
{
throw new ArgumentNullException(nameof(productsApi));
}
if (newCartItem.UserId != this.UserId)
{
throw new ArgumentException(
"Supplied cartItem has a different user then this user cart",
nameof(newCartItem));
}
// If the product is already in the cart, there's no need to check for existence from api.
bool newProduct = false;
if (!this.items.TryGetValue(newCartItem.ProductId, out UserCartItem userCartItem))
{
userCartItem = InitializeUserCartItem(productsApi, newCartItem.ProductId);
newProduct = true;
}
userCartItem.IncreaseQuantity(productsApi, newCartItem.Quantity);
if (newProduct)
{
this.items.Add(userCartItem.ProductId, userCartItem);
}
}
private UserCart InitializeUserCart(NewCartItem cartItem)
{
if (!this.userApi.UserExists(cartItem.UserId))
{
throw new CartException(
CartErrorCode.InvalidUser,
"Invalid user");
}
return(new UserCart(cartItem.UserId));
}
/// <summary>
/// Adds new cart item to the specified user.
/// If the product is already in cart increases its quantity
/// </summary>
/// <param name="cartItem">Cart item to be added.</param>
/// <returns>Awaitable task</returns>
public async Task AddCartItemAsync(NewCartItem cartItem)
{
var userCart = await this.dataGateway.GetUserCartAsync(cartItem.UserId)
.ConfigureAwait(false);
if (userCart == null)
{
userCart = this.InitializeUserCart(cartItem);
}
// No need to check for existing user since the user cart is already created.
userCart.AddToCart(this.productsApi, cartItem);
await this.dataGateway.SaveUserCartAsync(userCart).ConfigureAwait(false);
}