// Copyright (c) .NET Foundation. All rights reserved.
// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.

using System;
using System.Collections.Generic;
using System.IO;
using System.Net.Http;
using System.Reflection;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Mvc.ApplicationParts;
using Microsoft.AspNetCore.Mvc.Controllers;
using Microsoft.AspNetCore.Mvc.Infrastructure;
using Microsoft.AspNetCore.Mvc.ViewComponents;
using Microsoft.AspNetCore.TestHost;
using Microsoft.AspNetCore.Testing;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.PlatformAbstractions;

namespace Microsoft.AspNetCore.Mvc.FunctionalTests
{
    public class MvcTestFixture<TStartup> : IDisposable
    {
        private const string SolutionName = "Mvc.sln";
        private readonly TestServer _server;

        public MvcTestFixture()
            : this(Path.Combine("test", "WebSites"))
        {
        }

        protected MvcTestFixture(string solutionRelativePath)
        {
            // RequestLocalizationOptions saves the current culture when constructed, potentially changing response
            // localization i.e. RequestLocalizationMiddleware behavior. Ensure the saved culture
            // (DefaultRequestCulture) is consistent regardless of system configuration or personal preferences.
            using (new CultureReplacer())
            {
                var builder = new WebHostBuilder()
                    .UseContentRoot(GetApplicationPath(solutionRelativePath))
                    .ConfigureServices(InitializeServices)
                    .UseStartup(typeof(TStartup));

                _server = new TestServer(builder);
            }

            Client = _server.CreateClient();
            Client.BaseAddress = new Uri("http://localhost");
        }

        public HttpClient Client { get; }

        public void Dispose()
        {
            Client.Dispose();
            _server.Dispose();
        }

        private static string GetApplicationPath(string solutionRelativePath)
        {
            var startupAssembly = typeof(TStartup).GetTypeInfo().Assembly;
            var applicationName = startupAssembly.GetName().Name;
            var applicationBasePath = PlatformServices.Default.Application.ApplicationBasePath;

            var directoryInfo = new DirectoryInfo(applicationBasePath);
            do
            {
                var solutionFileInfo = new FileInfo(Path.Combine(directoryInfo.FullName, SolutionName));
                if (solutionFileInfo.Exists)
                {
                    return Path.Combine(directoryInfo.FullName, solutionRelativePath, applicationName);
                }

                directoryInfo = directoryInfo.Parent;
            }
            while (directoryInfo.Parent != null);

            throw new Exception($"Solution root could not be located using application root {applicationBasePath}.");
        }

        protected virtual void InitializeServices(IServiceCollection services)
        {
            var startupAssembly = typeof(TStartup).GetTypeInfo().Assembly;

            // Inject a custom application part manager. Overrides AddMvcCore() because that uses TryAdd().
            var manager = new ApplicationPartManager();
            manager.ApplicationParts.Add(new AssemblyPart(startupAssembly));

            manager.FeatureProviders.Add(new ControllerFeatureProvider());
            manager.FeatureProviders.Add(new ViewComponentFeatureProvider());

            services.AddSingleton(manager);
        }
    }
}