public BasketPricingResults PriceBasket(Basket basket, IEnumerable <IBasketPricingOffer> offers = null)
{
var results = new BasketPricingResults {
ItemCount = 0
};
var isValidationFailed = this.ValidateBasket(basket, results);
if (isValidationFailed)
{
return(results);
}
var isPricingFailed = this.TryToPriceBasket(basket, results);
this.CalculateTotalPrice(results);
if (isPricingFailed)
{
return(results);
}
this.TryToApplySpecialOffers(basket, results, offers);
this.CalculateDiscountedPrices(results);
if (results.FullPrice == results.DiscountedPrice)
{
results.Messages.Add(Errors.NoOffersAvailable);
}
return(results);
}
private void CalculateDiscountedPrices(BasketPricingResults results)
{
var discount = 0m;
foreach (var item in results.ItemPrices)
{
discount += item.Discount ?? 0;
}
results.DiscountedPrice = results.FullPrice - discount;
}
private void TryToApplySpecialOffers(Basket basket, BasketPricingResults results, IEnumerable <IBasketPricingOffer> offers)
{
if (offers != null && offers.Any())
{
var itemsByName = results.ItemPrices.ToDictionary(x => x.Name, StringComparer.OrdinalIgnoreCase);
foreach (var item in offers)
{
item.ApplyOffers(itemsByName, results);
}
}
}
private bool TryToPriceBasket(Basket basket, BasketPricingResults results)
{
var pricesToAsk = basket.Items.Select(x => x.Name).Distinct(StringComparer.OrdinalIgnoreCase);
var prices = this.priceRepository.GetItemPrices(pricesToAsk);
var pricesByName = prices.ToDictionary(x => x.Name, StringComparer.OrdinalIgnoreCase);
results.ItemPrices = new List <BasketItemPrice>();
var isFailed = false;
var itemCount = 0;
foreach (var item in basket.Items.GroupBy(x => x.Name))
{
var itemName = item.Key;
var quantity = item.Count();
var itemPrice = pricesByName.TryGetValue(itemName, out var price) ? price.Price : default(decimal?);
var baskItemPrice =
new BasketItemPrice
{
Name = item.Key,
UnitPrice = itemPrice,
Quantity = quantity
};
itemCount += quantity;
results.ItemPrices.Add(baskItemPrice);
if (!baskItemPrice.UnitPrice.HasValue)
{
results.Messages.Add(string.Format(Errors.PriceUnavailable, baskItemPrice.Name));
isFailed = true;
}
}
results.ItemCount = itemCount;
return(isFailed);
}
private bool ValidateBasket(Basket basket, BasketPricingResults results)
{
var isFailed = false;
if (results.Messages == null)
{
results.Messages = new List <string>();
}
if (basket is null)
{
results.Messages.Add(Errors.BasketIsNull);
return(true);
}
if (basket.Items == null || !basket.Items.Any())
{
results.Messages.Add(Errors.BasketIsEmpty);
isFailed = true;
}
return(isFailed);
}
private void CalculateTotalPrice(BasketPricingResults results)
{
var totalPrice = results.ItemPrices.Where(x => x.UnitPrice.HasValue).Select(this.CalculatePrice).Sum();
results.FullPrice = totalPrice;
}