using System;
using System.Threading.Tasks;
using Microsoft.eShopWeb.ApplicationCore.Entities.BasketAggregate;
using Microsoft.eShopWeb.ApplicationCore.Interfaces;
using Microsoft.eShopWeb.ApplicationCore.Services;
using Microsoft.eShopWeb.ApplicationCore.Specifications;
using Moq;
using Xunit;

namespace Microsoft.eShopWeb.UnitTests.ApplicationCore.Services.BasketServiceTests;

public class TransferBasket
{
    private readonly string _nonexistentAnonymousBasketBuyerId = "nonexistent-anonymous-basket-buyer-id";
    private readonly string _existentAnonymousBasketBuyerId = "existent-anonymous-basket-buyer-id";
    private readonly string _nonexistentUserBasketBuyerId = "newuser@microsoft.com";
    private readonly string _existentUserBasketBuyerId = "testuser@microsoft.com";
    private readonly Mock<IRepository<Basket>> _mockBasketRepo = new();

    [Fact]
    public async Task ThrowsGivenNullAnonymousId()
    {
        var basketService = new BasketService(null, null);

        await Assert.ThrowsAsync<ArgumentNullException>(async () => await basketService.TransferBasketAsync(null, "steve"));
    }

    [Fact]
    public async Task ThrowsGivenNullUserId()
    {
        var basketService = new BasketService(null, null);

        await Assert.ThrowsAsync<ArgumentNullException>(async () => await basketService.TransferBasketAsync("abcdefg", null));
    }

    [Fact]
    public async Task InvokesBasketRepositoryFirstOrDefaultAsyncOnceIfAnonymousBasketNotExists()
    {
        var anonymousBasket = null as Basket;
        var userBasket = new Basket(_existentUserBasketBuyerId);
        _mockBasketRepo.SetupSequence(x => x.GetBySpecAsync(It.IsAny<BasketWithItemsSpecification>(), default))
            .ReturnsAsync(anonymousBasket)
            .ReturnsAsync(userBasket);
        var basketService = new BasketService(_mockBasketRepo.Object, null);
        await basketService.TransferBasketAsync(_nonexistentAnonymousBasketBuyerId, _existentUserBasketBuyerId);
        _mockBasketRepo.Verify(x => x.GetBySpecAsync(It.IsAny<BasketWithItemsSpecification>(), default), Times.Once);
    }

    [Fact]
    public async Task TransferAnonymousBasketItemsWhilePreservingExistingUserBasketItems()
    {
        var anonymousBasket = new Basket(_existentAnonymousBasketBuyerId);
        anonymousBasket.AddItem(1, 10, 1);
        anonymousBasket.AddItem(3, 55, 7);
        var userBasket = new Basket(_existentUserBasketBuyerId);
        userBasket.AddItem(1, 10, 4);
        userBasket.AddItem(2, 99, 3);
        _mockBasketRepo.SetupSequence(x => x.GetBySpecAsync(It.IsAny<BasketWithItemsSpecification>(), default))
            .ReturnsAsync(anonymousBasket)
            .ReturnsAsync(userBasket);
        var basketService = new BasketService(_mockBasketRepo.Object, null);
        await basketService.TransferBasketAsync(_nonexistentAnonymousBasketBuyerId, _existentUserBasketBuyerId);
        _mockBasketRepo.Verify(x => x.UpdateAsync(userBasket, default), Times.Once);
        Assert.Equal(3, userBasket.Items.Count);
        Assert.Contains(userBasket.Items, x => x.CatalogItemId == 1 && x.UnitPrice == 10 && x.Quantity == 5);
        Assert.Contains(userBasket.Items, x => x.CatalogItemId == 2 && x.UnitPrice == 99 && x.Quantity == 3);
        Assert.Contains(userBasket.Items, x => x.CatalogItemId == 3 && x.UnitPrice == 55 && x.Quantity == 7);
    }

    [Fact]
    public async Task RemovesAnonymousBasketAfterUpdatingUserBasket()
    {
        var anonymousBasket = new Basket(_existentAnonymousBasketBuyerId);
        var userBasket = new Basket(_existentUserBasketBuyerId);
        _mockBasketRepo.SetupSequence(x => x.GetBySpecAsync(It.IsAny<BasketWithItemsSpecification>(), default))
            .ReturnsAsync(anonymousBasket)
            .ReturnsAsync(userBasket);
        var basketService = new BasketService(_mockBasketRepo.Object, null);
        await basketService.TransferBasketAsync(_nonexistentAnonymousBasketBuyerId, _existentUserBasketBuyerId);
        _mockBasketRepo.Verify(x => x.UpdateAsync(userBasket, default), Times.Once);
        _mockBasketRepo.Verify(x => x.DeleteAsync(anonymousBasket, default), Times.Once);
    }

    [Fact]
    public async Task CreatesNewUserBasketIfNotExists()
    {
        var anonymousBasket = new Basket(_existentAnonymousBasketBuyerId);
        var userBasket = null as Basket;
        _mockBasketRepo.SetupSequence(x => x.GetBySpecAsync(It.IsAny<BasketWithItemsSpecification>(), default))
            .ReturnsAsync(anonymousBasket)
            .ReturnsAsync(userBasket);
        var basketService = new BasketService(_mockBasketRepo.Object, null);
        await basketService.TransferBasketAsync(_existentAnonymousBasketBuyerId, _nonexistentUserBasketBuyerId);
        _mockBasketRepo.Verify(x => x.AddAsync(It.Is<Basket>(x => x.BuyerId == _nonexistentUserBasketBuyerId), default), Times.Once);
    }
}