/// <summary>
/// Buy product and move buffered coins to saved amount
/// </summary>
/// <param name="productNumber">Ordered product id</param>
/// <returns>Ordered product</returns>
public Product Buy(int productNumber)
{
if (Products.Length >= productNumber)
{
var backedProducts = Products;
var product = Products[productNumber - 1];
try
{
_library.UnfillProduct(productNumber);
}
catch (Exception ex)
{
Products = backedProducts;
throw ex;
}
var backedAmount = _moneyHolder.GetAccountedAmount();
var backedOrder = _moneyHolder.GetBufferedAmount();
try
{
// processing money
_moneyHolder.AddAccountedAmount(product.Price);
_moneyHolder.SubstractBufferedAmount(product.Price);
return(product);
}
catch (Exception ex)
{
//in case of any problems with money calculation
//revert all transactions and revert product status
Products = backedProducts;
_moneyHolder.SetAccountedAmount(backedAmount);
_moneyHolder.SetBuffedAmount(backedOrder);
throw ex;
}
}
else
{
throw new IndexOutOfRangeException("Product does not exist");
}
}
