Delegate.cs

public class OrderService : IOrderService
{
    private readonly IRepository<Order> _orderRepository;
    private readonly IUriComposer _uriComposer;
    private readonly UtcNow _utcNow;
    private readonly IRepository<Basket> _basketRepository;
    private readonly IRepository<CatalogItem> _itemRepository;

    public OrderServiceDelegate(IRepository<Basket> basketRepository,
        IRepository<CatalogItem> itemRepository,
        IRepository<Order> orderRepository,
        IUriComposer uriComposer,
        UtcNow utcNow)
    {
        _orderRepository = orderRepository;
        _uriComposer = uriComposer;
        _utcNow = utcNow;
        _basketRepository = basketRepository;
        _itemRepository = itemRepository;
    }

    public async Task<Order> CreateOrderAsync(int basketId, Address shippingAddress)
    {
        var basket = await _basketRepository.GetByIdAsync(basketId);

        Guard.Against.NullBasket(basketId, basket);
        Guard.Against.EmptyBasketOnCheckout(basket.Items);

        var catalogItemsSpecification = new CatalogItemsSpecification(basket.Items.Select(item => item.CatalogItemId).ToArray());
        var catalogItems = await _itemRepository.ListAsync(catalogItemsSpecification);

        var items = basket.Items.Select(basketItem =>
        {
            var catalogItem = catalogItems.First(c => c.Id == basketItem.CatalogItemId);
            var itemOrdered = new CatalogItemOrdered(catalogItem.Id, catalogItem.Name, _uriComposer.ComposePicUri(catalogItem.PictureUri));
            var orderItem = new OrderItem(itemOrdered, basketItem.UnitPrice, basketItem.Quantity);
            return orderItem;
        }).ToList();

        var now = _utcNow();
        var order = new Order(basket.BuyerId, shippingAddress, items, now);

        await _orderRepository.AddAsync(order);

        return order;
    }
}