public void AddItemToCheckout(int sku, decimal quantity, MeasurmentUnits buyUnit, DiscountRule discountRule)
{
// First get the product with the corresponding SKU from repository
var product = _productsRepo.GetProduct(sku);
if (product == null)
{
throw new ArgumentException($"Cannot find product with SKU : {sku}");
}
if (product.UnitPrice <= 0)
{
throw new ArgumentOutOfRangeException("Cannot add a product with invalid price");
}
if (quantity <= 0)
{
throw new ArgumentOutOfRangeException("Cannot add a product with negative or zero quantity");
}
if (product.MeasurmentUnit == MeasurmentUnits.PIECE && quantity != Math.Round(quantity))
{
throw new ArgumentException("Cannot add product sold by number with a floating decimal quantity");
}
if (product.MeasurmentUnit != buyUnit)
{
try
{
// get the quantity corresponding to the sell unit, rounded to 3 decimals
quantity = Math.Round(GetQuantityFromUnit(quantity, product.MeasurmentUnit, buyUnit), 3);
}
catch (Exception e)
{
throw new ArgumentException(e.Message + $": Sell Unit {product.MeasurmentUnit}, Buy Unit {buyUnit}");
}
}
if (discountRule != null)
{
discountRule = ConfigureDiscountRuleParams(discountRule.Id, product.UnitPrice);
}
// Finally add a "quantity" of this product to the list of
// checkout items if all the checking conditions are met
_checkoutRepo.AddItem(product, quantity, buyUnit, discountRule);
}