public async Task <Purchase> PurchaseProduct(string userId, int productId, int quantity)
{
using (var tx = await db.Database.BeginTransactionAsync())
{
if (quantity < 1)
{
throw new ArgumentException("Quantity must be greater or equal to 1", nameof(quantity));
}
;
var product = await db.Products.FindAsync(productId);
if (product == null)
{
throw new ArgumentException($"Unknown product: {productId}", nameof(productId));
}
if (product.IsDeleted)
{
throw new InvalidOperationException($"Product {productId} is deleted");
}
var user = await db.Users.FindAsync(userId);
if (user == null)
{
throw new ArgumentException($"Unknown user: {userId}", nameof(userId));
}
if (user.IsDeleted)
{
throw new InvalidOperationException($"User {userId} is deleted");
}
var purchase = new Purchase
{
Product = product,
Quantity = quantity,
ProductPrice = product.Price,
ProductName = product.Name,
Amount = quantity * product.Price
};
RecordTransaction(purchase, user);
await db.SaveChangesAsync();
tx.Commit();
return(purchase);
}
}
private async Task Run(SubscriptionFrequency frequency)
{
using (var tx = await db.Database.BeginTransactionAsync())
{
var subscriptions = await GetSubscriptions(frequency);
foreach (var subscription in subscriptions)
{
Process(subscription);
}
await db.SaveChangesAsync();
tx.Commit();
}
}
