using System;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNet.Http;
using Microsoft.AspNet.Http.Features;
using Microsoft.AspNet.Http.Internal;
using Microsoft.AspNet.Mvc;
using Microsoft.AspNet.Session;
using Microsoft.Framework.Caching.Distributed;
using Microsoft.Framework.Caching.Memory;
using Microsoft.Framework.DependencyInjection;
using Microsoft.Framework.Logging.Testing;
using MusicStore.Models;
using Xunit;

namespace MusicStore.Components
{
    public class CartSummaryComponentTest
    {
        private readonly IServiceProvider _serviceProvider;

        public CartSummaryComponentTest()
        {
            var services = new ServiceCollection();

            services.AddEntityFramework()
                      .AddInMemoryStore()
                      .AddDbContext<MusicStoreContext>();

            _serviceProvider = services.BuildServiceProvider();
        }

        [Fact]
        public async Task CartSummaryComponent_Returns_CartedItems()
        {
            // Arrange
            var viewContext = new ViewContext()
            {
                HttpContext = new DefaultHttpContext()
            };

            // Session initialization
            var cartId = "CartId_A";
            var sessionFeature = new SessionFeature()
            {
                Session = CreateTestSession(),
            };
            viewContext.HttpContext.SetFeature<ISessionFeature>(sessionFeature);
            viewContext.HttpContext.Session.SetString("Session", cartId);

            // DbContext initialization
            var dbContext = _serviceProvider.GetRequiredService<MusicStoreContext>();
            PopulateData(dbContext, cartId, albumTitle: "AlbumA", itemCount: 10);

            // CartSummaryComponent initialization
            var cartSummaryComponent = new CartSummaryComponent()
            {
                DbContext = dbContext,
                ViewContext = viewContext,
            };

            // Act
            var result = await cartSummaryComponent.InvokeAsync();

            // Assert
            Assert.NotNull(result);
            var viewResult = Assert.IsType<ViewViewComponentResult>(result);
            Assert.Null(viewResult.ViewName);
            Assert.Null(viewResult.ViewData.Model);
            Assert.Equal(10, cartSummaryComponent.ViewBag.CartCount);
            Assert.Equal("AlbumA", cartSummaryComponent.ViewBag.CartSummary);
        }

        private static ISession CreateTestSession()
        {
            return new DistributedSession(
                new LocalCache(new MemoryCache(new MemoryCacheOptions())),
                "sessionId_A",
                idleTimeout: TimeSpan.MaxValue,
                tryEstablishSession: () => true,
                loggerFactory: new NullLoggerFactory(),
                isNewSessionKey: true);
        }

        private static void PopulateData(MusicStoreContext context, string cartId, string albumTitle, int itemCount)
        {
            var album = new Album()
            {
                AlbumId = 1,
                Title = albumTitle,
            };

            var cartItems = Enumerable.Range(1, itemCount).Select(n =>
                new CartItem()
                {
                    AlbumId = 1,
                    Album = album,
                    Count = 1,
                    CartId = cartId,
                }).ToArray();

            context.AddRange(cartItems);
            context.SaveChanges();
        }
    }
}