using System;
using System.Linq;
using System.Net.Http;
using System.Net.Http.Headers;
using System.Security.Claims;
using System.Text.Encodings.Web;
using System.Threading.Tasks;
using Microsoft.AspNet.Authentication.Cookies;
using Microsoft.AspNet.Authentication.Facebook;
using Microsoft.AspNet.Authentication.Google;
using Microsoft.AspNet.Authentication.MicrosoftAccount;
using Microsoft.AspNet.Authentication.OAuth;
using Microsoft.AspNet.Authentication.Twitter;
using Microsoft.AspNet.Builder;
using Microsoft.AspNet.Hosting;
using Microsoft.AspNet.Http;
using Microsoft.AspNet.Http.Authentication;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;
using Newtonsoft.Json.Linq;

namespace CookieSample
{
    /* Note all servers must use the same address and port because these are pre-registered with the various providers. */
    public class Startup
    {
        public Startup()
        {
            Configuration = new ConfigurationBuilder()
                .AddEnvironmentVariables()
                .AddJsonFile("config.json")
                .AddUserSecrets()
                .Build();
        }

        public IConfiguration Configuration { get; set; }

        public void ConfigureServices(IServiceCollection services)
        {
            services.AddAuthentication(options => options.SignInScheme = CookieAuthenticationDefaults.AuthenticationScheme);
        }

        public void Configure(IApplicationBuilder app, ILoggerFactory loggerfactory)
        {
            loggerfactory.AddConsole(LogLevel.Information);

            // Simple error page to avoid a repo dependency.
            app.Use(async (context, next) =>
            {
                try
                {
                    await next();
                }
                catch (Exception ex)
                {
                    if (context.Response.HasStarted)
                    {
                        throw;
                    }
                    context.Response.StatusCode = 500;
                    await context.Response.WriteAsync(ex.ToString());
                }
            });

            app.UseCookieAuthentication(options =>
            {
                options.AutomaticAuthenticate = true;
                options.AutomaticChallenge = true;
                options.LoginPath = new PathString("/login");
            });

            // You must first create an app with facebook and add it's ID and Secret to your config.json or user-secrets.
            // https://developers.facebook.com/apps/
            app.UseFacebookAuthentication(options =>
            {
                options.AppId = Configuration["facebook:appid"];
                options.AppSecret = Configuration["facebook:appsecret"];
                options.Scope.Add("email");
                options.Fields.Add("name");
                options.Fields.Add("email");
            });

            // See config.json
            app.UseOAuthAuthentication(options =>
            {
                options.AuthenticationScheme = "Google-AccessToken";
                options.DisplayName = "Google-AccessToken";
                options.ClientId = Configuration["google:clientid"];
                options.ClientSecret = Configuration["google:clientsecret"];
                options.CallbackPath = new PathString("/signin-google-token");
                options.AuthorizationEndpoint = GoogleDefaults.AuthorizationEndpoint;
                options.TokenEndpoint = GoogleDefaults.TokenEndpoint;
                options.Scope.Add("openid");
                options.Scope.Add("profile");
                options.Scope.Add("email");
                options.SaveTokensAsClaims = true;
            });

            // See config.json
            // https://console.developers.google.com/project
            app.UseGoogleAuthentication(options =>
            {
                options.ClientId = Configuration["google:clientid"];
                options.ClientSecret = Configuration["google:clientsecret"];
                options.Events = new OAuthEvents()
                {
                    OnRemoteFailure = ctx =>

                    {
                        ctx.Response.Redirect("/error?FailureMessage=" + UrlEncoder.Default.Encode(ctx.Failure.Message));
                        ctx.HandleResponse();
                        return Task.FromResult(0);
                    }
                };

            });

            // See config.json
            // https://apps.twitter.com/
            app.UseTwitterAuthentication(options =>
            {
                options.ConsumerKey = Configuration["twitter:consumerkey"];
                options.ConsumerSecret = Configuration["twitter:consumersecret"];
                options.Events = new TwitterEvents()
                {
                    OnRemoteFailure = ctx =>
                    {
                        ctx.Response.Redirect("/error?FailureMessage=" + UrlEncoder.Default.Encode(ctx.Failure.Message));
                        ctx.HandleResponse();
                        return Task.FromResult(0);
                    }
                };
            });

            // You must first create an app with live.com and add it's ID and Secret to your config.json or user-secrets.
            /* https://account.live.com/developers/applications
            The MicrosoftAccount service has restrictions that prevent the use of http://localhost:54540/ for test applications.
            As such, here is how to change this sample to uses http://mssecsample.localhost.this:54540/ instead.

            Edit the Project.json file and replace http://localhost:54540/ with http://mssecsample.localhost.this:54540/.

            From an admin command console first enter:
             notepad C:\Windows\System32\drivers\etc\hosts
            and add this to the file, save, and exit (and reboot?):
             127.0.0.1 MsSecSample.localhost.this

            Then you can choose to run the app as admin (see below) or add the following ACL as admin:
             netsh http add urlacl url=http://mssecsample.localhost.this:54540/ user=[domain\user]

            The sample app can then be run via:
             dnx . web
            */
            app.UseOAuthAuthentication(options => 
            {
                options.AuthenticationScheme = "Microsoft-AccessToken";
                options.DisplayName = "MicrosoftAccount-AccessToken - Requires project changes";
                options.ClientId = Configuration["msa:clientid"];
                options.ClientSecret = Configuration["msa:clientsecret"];
                options.CallbackPath = new PathString("/signin-microsoft-token");
                options.AuthorizationEndpoint = MicrosoftAccountDefaults.AuthorizationEndpoint;
                options.TokenEndpoint = MicrosoftAccountDefaults.TokenEndpoint;
                options.Scope.Add("wl.basic");
                options.SaveTokensAsClaims = true;
            });

            //// You must first create an app with live.com and add it's ID and Secret to your config.json or user-secrets.
            app.UseMicrosoftAccountAuthentication(options =>
            {
                options.DisplayName = "MicrosoftAccount - Requires project changes";
                options.ClientId = Configuration["msa:clientid"];
                options.ClientSecret = Configuration["msa:clientsecret"];
                options.Scope.Add("wl.emails");
            });

            // See config.json
            // https://github.com/settings/applications/
            app.UseOAuthAuthentication(options =>
            {
                options.AuthenticationScheme = "GitHub-AccessToken";
                options.DisplayName = "Github-AccessToken";
                options.ClientId = Configuration["github-token:clientid"];
                options.ClientSecret = Configuration["github-token:clientsecret"];
                options.CallbackPath = new PathString("/signin-github-token");
                options.AuthorizationEndpoint = "https://github.com/login/oauth/authorize";
                options.TokenEndpoint = "https://github.com/login/oauth/access_token";
                options.SaveTokensAsClaims = true;
            });

            // See config.json
            app.UseOAuthAuthentication(options =>
            {
                options.AuthenticationScheme = "GitHub";
                options.DisplayName = "Github";
                options.ClientId = Configuration["github:clientid"];
                options.ClientSecret = Configuration["github:clientsecret"];
                options.CallbackPath = new PathString("/signin-github");
                options.AuthorizationEndpoint = "https://github.com/login/oauth/authorize";
                options.TokenEndpoint = "https://github.com/login/oauth/access_token";
                options.UserInformationEndpoint = "https://api.github.com/user";
                options.ClaimsIssuer = "OAuth2-Github";
                // Retrieving user information is unique to each provider.
                options.Events = new OAuthEvents
                {
                    OnCreatingTicket = async context =>
                    {
                        // Get the GitHub user
                        var request = new HttpRequestMessage(HttpMethod.Get, context.Options.UserInformationEndpoint);
                        request.Headers.Authorization = new AuthenticationHeaderValue("Bearer", context.AccessToken);
                        request.Headers.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));

                        var response = await context.Backchannel.SendAsync(request, context.HttpContext.RequestAborted);
                        response.EnsureSuccessStatusCode();

                        var user = JObject.Parse(await response.Content.ReadAsStringAsync());

                        var identifier = user.Value<string>("id");
                        if (!string.IsNullOrEmpty(identifier))
                        {
                            context.Identity.AddClaim(new Claim(
                                ClaimTypes.NameIdentifier, identifier,
                                ClaimValueTypes.String, context.Options.ClaimsIssuer));
                        }

                        var userName = user.Value<string>("login");
                        if (!string.IsNullOrEmpty(userName))
                        {
                            context.Identity.AddClaim(new Claim(
                                ClaimsIdentity.DefaultNameClaimType, userName,
                                ClaimValueTypes.String, context.Options.ClaimsIssuer));
                        }

                        var name = user.Value<string>("name");
                        if (!string.IsNullOrEmpty(name))
                        {
                            context.Identity.AddClaim(new Claim(
                                "urn:github:name", name,
                                ClaimValueTypes.String, context.Options.ClaimsIssuer));
                        }

                        var link = user.Value<string>("url");
                        if (!string.IsNullOrEmpty(link))
                        {
                            context.Identity.AddClaim(new Claim(
                                "urn:github:url", link,
                                ClaimValueTypes.String, context.Options.ClaimsIssuer));
                        }
                    }
                };
            });

            // Choose an authentication type
            app.Map("/login", signoutApp =>
            {
                signoutApp.Run(async context =>
                {
                    var authType = context.Request.Query["authscheme"];
                    if (!string.IsNullOrEmpty(authType))
                    {
                        // By default the client will be redirect back to the URL that issued the challenge (/login?authtype=foo),
                        // send them to the home page instead (/).
                        await context.Authentication.ChallengeAsync(authType, new AuthenticationProperties() { RedirectUri = "/" });
                        return;
                    }

                    context.Response.ContentType = "text/html";
                    await context.Response.WriteAsync("<html><body>");
                    await context.Response.WriteAsync("Choose an authentication scheme: <br>");
                    foreach (var type in context.Authentication.GetAuthenticationSchemes())
                    {
                        await context.Response.WriteAsync("<a href=\"?authscheme=" + type.AuthenticationScheme + "\">" + (type.DisplayName ?? "(suppressed)") + "</a><br>");
                    }
                    await context.Response.WriteAsync("</body></html>");
                });
            });

            // Sign-out to remove the user cookie.
            app.Map("/logout", signoutApp =>
            {
                signoutApp.Run(async context =>
                {
                    context.Response.ContentType = "text/html";
                    await context.Authentication.SignOutAsync(CookieAuthenticationDefaults.AuthenticationScheme);
                    await context.Response.WriteAsync("<html><body>");
                    await context.Response.WriteAsync("You have been logged out. Goodbye " + context.User.Identity.Name + "<br>");
                    await context.Response.WriteAsync("<a href=\"/\">Home</a>");
                    await context.Response.WriteAsync("</body></html>");
                });
            });

            // Display the remote error
            app.Map("/error", errorApp =>
            {
                errorApp.Run(async context =>
                {
                    context.Response.ContentType = "text/html";
                    await context.Response.WriteAsync("<html><body>");
                    await context.Response.WriteAsync("An remote failure has occurred: " + context.Request.Query["FailureMessage"] + "<br>");
                    await context.Response.WriteAsync("<a href=\"/\">Home</a>");
                    await context.Response.WriteAsync("</body></html>");
                });
            });

            // Deny anonymous request beyond this point.
            app.Use(async (context, next) =>
            {
                if (!context.User.Identities.Any(identity => identity.IsAuthenticated))
                {
                    // The cookie middleware will intercept this 401 and redirect to /login
                    await context.Authentication.ChallengeAsync();
                    return;
                }
                await next();
            });

            // Display user information
            app.Run(async context =>
            {
                context.Response.ContentType = "text/html";
                await context.Response.WriteAsync("<html><body>");
                await context.Response.WriteAsync("Hello " + (context.User.Identity.Name ?? "anonymous") + "<br>");
                foreach (var claim in context.User.Claims)
                {
                    await context.Response.WriteAsync(claim.Type + ": " + claim.Value + "<br>");
                }
                await context.Response.WriteAsync("<a href=\"/logout\">Logout</a>");
                await context.Response.WriteAsync("</body></html>");
            });
        }

        public static void Main(string[] args)
        {
            var application = new WebApplicationBuilder()
                .UseConfiguration(WebApplicationConfiguration.GetDefault(args))
                .UseStartup<Startup>()
                .Build();

            application.Run();
        }
    }
}