public async Task Given_ShopperHistory_When_Sort_Returns_MostBoughtProductsFirst()
{
// Arrange.
var shopperHistory = new List <ShopperHistoryResponse>
{
new ShopperHistoryResponse {
CustomerId = "1",
Products = new List <Product>
{
new Product {
Name = "a", Quantity = 2d
},
new Product {
Name = "b", Quantity = 3d
}
}
},
new ShopperHistoryResponse {
CustomerId = "2",
Products = new List <Product>
{
new Product {
Name = "a", Quantity = 1d
},
new Product {
Name = "b", Quantity = 1d
},
new Product {
Name = "c", Quantity = 1d
}
}
},
};
_shopperHistoryRepository.Get(Arg.Any <string>()).Returns(shopperHistory);
var productsToSort = new List <Product>
{
new Product {
Name = "a"
},
new Product {
Name = "b"
},
new Product {
Name = "d"
},
};
// Act.
var result = await _sut.Sort(SortOptions.RECOMMENDED, productsToSort);
// Assert.
result[0].Should().Be(productsToSort[1]);
result[1].Should().Be(productsToSort[0]);
result[2].Should().Be(productsToSort[2]);
}
public async Task <IReadOnlyList <Product> > Sort(SortOptions option, List <Product> products)
{
var shopperHistory = await _shopperHistoryRepository.Get(_configuration["UserToken"]);
var productIdAndPurchaseCountMap = GetProductIdPurchaseCountMap(shopperHistory);
return((from eachProduct in products
join eachPurchaseHisotry in productIdAndPurchaseCountMap
on eachProduct.Name equals eachPurchaseHisotry.Item1
into gj
from subPurchaseHistory in gj.DefaultIfEmpty()
select new
{
Product = eachProduct,
PurchaseCount = subPurchaseHistory == null ? 0d : subPurchaseHistory.Item2
})
.OrderByDescending(r => r.PurchaseCount)
.Select(r => r.Product)
.ToList());
}