// The transaction is handled here
public void Receipt(string username, int productID, int quantity)
{
User user;
Product product;
// Checks whether a username as the given, exists
if (_stregsystem.GetUserByUsername(username) != null)
{
user = _stregsystem.GetUserByUsername(username);
// Checks whether a product ID as the given, exists
if (_stregsystem.GetProductByID(productID) != null)
{
product = _stregsystem.GetProductByID(productID);
// Checks whether the product is active
if (product.Active)
{
// Checks if the user can afford the product and the quantity of it, and if not, if the product can be bought on credit
if (product.Price * quantity <= user.Balance || product.CanBeBoughtOnCredit)
{
BuyTransaction purchase = null;
for (int i = 0; i < quantity; i++)
{
purchase = _stregsystem.BuyProduct(user, product);
}
ConsoleReceipt receipt = new ConsoleReceipt(purchase, quantity, false);
receipt.Print();
}
else
{
_ui.DisplayInsufficientCash(user, product);
}
}
else
{
_ui.DisplayProductNotActive($"{product.ID}");
}
}
else
{
_ui.DisplayProductNotFound();
}
}
else
{
_ui.DisplayUserNotFound(username);
}
}