// 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.Threading.Tasks;
using Microsoft.AspNet.Builder;
using Microsoft.AspNet.Http;
using Microsoft.AspNet.Server.WebListener;
using Microsoft.Framework.ConfigurationModel;
using Microsoft.Framework.DependencyInjection;
using Microsoft.Framework.Logging;
using Microsoft.Framework.Runtime;
using Microsoft.Net.Http.Server;

namespace ServerComparison.TestSites
{
    /// <summary>
    /// To make runtime to load an environment based startup class, specify the environment by the following ways: 
    /// 1. Drop a Microsoft.AspNet.Hosting.ini file in the wwwroot folder
    /// 2. Add a setting in the ini file named 'ASPNET_ENV' with value of the format 'Startup[EnvironmentName]'. For example: To load a Startup class named
    /// 'StartupNtlmAuthentication' the value of the env should be 'NtlmAuthentication' (eg. ASPNET_ENV=NtlmAuthentication). Runtime adds a 'Startup' prefix to this and loads 'StartupNtlmAuthentication'. 
    /// If no environment name is specified the default startup class loaded is 'Startup'. 
    /// Alternative ways to specify environment are:
    /// 1. Set the environment variable named SET ASPNET_ENV=NtlmAuthentication
    /// 2. For selfhost based servers pass in a command line variable named --env with this value. Eg:
    /// "commands": {
    ///    "web": "Microsoft.AspNet.Hosting --server Microsoft.AspNet.Server.WebListener --server.urls http://localhost:5002 --ASPNET_ENV NtlmAuthentication",
    ///  },
    /// </summary>
    public class StartupNtlmAuthentication
    {
        public StartupNtlmAuthentication(IApplicationEnvironment env)
        {
            //Below code demonstrates usage of multiple configuration sources. For instance a setting say 'setting1' is found in both the registered sources, 
            //then the later source will win. By this way a Local config can be overridden by a different setting while deployed remotely.
            Configuration = new Configuration(env.ApplicationBasePath)
                        .AddJsonFile("config.json")
                        .AddEnvironmentVariables(); //All environment variables in the process's context flow in as configuration values.
        }

        public IConfiguration Configuration { get; private set; }

        public void ConfigureServices(IServiceCollection services)
        {
        }

        public void Configure(IApplicationBuilder app, ILoggerFactory loggerFactory)
        {
            loggerFactory.AddConsole(minLevel: LogLevel.Warning);

            // Set up NTLM authentication for WebListener like below.
            // For IIS and IISExpress: Use inetmgr to setup NTLM authentication on the application vDir or modify the applicationHost.config to enable NTLM.
            if ((app.Server as ServerInformation) != null)
            {
                var serverInformation = (ServerInformation)app.Server;
                serverInformation.Listener.AuthenticationManager.AuthenticationSchemes = AuthenticationSchemes.NTLM | AuthenticationSchemes.AllowAnonymous;
            }

            app.Use((context, next) =>
            {
                if (context.Request.Path.Equals(new PathString("/Anonymous")))
                {
                    return context.Response.WriteAsync("Anonymous?" + !context.User.Identity.IsAuthenticated);
                }

                if (context.Request.Path.Equals(new PathString("/Restricted")))
                {
                    if (context.User.Identity.IsAuthenticated)
                    {
                        return context.Response.WriteAsync("NotAnonymous");
                    }
                    else
                    {
                        context.Authentication.Challenge();
                        return Task.FromResult(0);
                    }
                }

                return context.Response.WriteAsync("Hello World");
            });
        }
    }
}