private static (decimal total, List <BasketItem> basket) PairedBuy(string sku1, string sku2, decimal discountedPrice, List <BasketItem> basket)
{
bool ShouldApplyPromotion(List <BasketItem> basket)
{
return(basket.Exists(bi => bi.Sku == sku1 && bi.Quantity >= 1) &&
basket.Exists(bi => bi.Sku == sku2 && bi.Quantity >= 1));
}
var total = 0M;
while (ShouldApplyPromotion(basket))
{
basket = basket
.Select(bi => Promotions.ReduceQuantityForSku(bi, sku1, 1))
.Select(bi => Promotions.ReduceQuantityForSku(bi, sku2, 1))
.Where(bi => bi.Quantity > 0).ToList();
total += discountedPrice;
}
return(total, basket);
}
public CalculatePromotion(Promotions promotions)
{
_promotions = promotions;
}