// 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.Linq;
using System.Net;
using System.Net.Http;
using System.Text;
using System.Text.Encodings.Web;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Authentication.Cookies;
using Microsoft.AspNetCore.Authentication.OAuth;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.DataProtection;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.TestHost;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging.Abstractions;
using Microsoft.Extensions.Options;
using Microsoft.Extensions.Options.Infrastructure;
using Newtonsoft.Json;
using Xunit;

namespace Microsoft.AspNetCore.Authentication.Facebook
{
    public class FacebookTests
    {
        [Fact]
        public async Task VerifySchemeDefaults()
        {
            var services = new ServiceCollection().AddFacebookAuthentication().AddSingleton<IConfiguration>(new ConfigurationBuilder().Build());
            var sp = services.BuildServiceProvider();
            var schemeProvider = sp.GetRequiredService<IAuthenticationSchemeProvider>();
            var scheme = await schemeProvider.GetSchemeAsync(FacebookDefaults.AuthenticationScheme);
            Assert.NotNull(scheme);
            Assert.Equal("FacebookHandler", scheme.HandlerType.Name);
            Assert.Equal(FacebookDefaults.AuthenticationScheme, scheme.DisplayName);
        }

        [Fact]
        public void AddCanBindAgainstDefaultConfig()
        {
            var dic = new Dictionary<string, string>
            {
                {"Microsoft:AspNetCore:Authentication:Schemes:Facebook:AppId", "<id>"},
                {"Microsoft:AspNetCore:Authentication:Schemes:Facebook:AppSecret", "<secret>"},
                {"Microsoft:AspNetCore:Authentication:Schemes:Facebook:AuthorizationEndpoint", "<authEndpoint>"},
                {"Microsoft:AspNetCore:Authentication:Schemes:Facebook:BackchannelTimeout", "0.0:0:30"},
                //{"Facebook:CallbackPath", "/callbackpath"}, // PathString doesn't convert
                {"Microsoft:AspNetCore:Authentication:Schemes:Facebook:ClaimsIssuer", "<issuer>"},
                {"Microsoft:AspNetCore:Authentication:Schemes:Facebook:RemoteAuthenticationTimeout", "0.0:0:30"},
                {"Microsoft:AspNetCore:Authentication:Schemes:Facebook:SaveTokens", "true"},
                {"Microsoft:AspNetCore:Authentication:Schemes:Facebook:SendAppSecretProof", "true"},
                {"Microsoft:AspNetCore:Authentication:Schemes:Facebook:SignInScheme", "<signIn>"},
                {"Microsoft:AspNetCore:Authentication:Schemes:Facebook:TokenEndpoint", "<tokenEndpoint>"},
                {"Microsoft:AspNetCore:Authentication:Schemes:Facebook:UserInformationEndpoint", "<userEndpoint>"},
            };
            var configurationBuilder = new ConfigurationBuilder();
            configurationBuilder.AddInMemoryCollection(dic);
            var config = configurationBuilder.Build();
            var services = new ServiceCollection()
                .AddSingleton<IConfigureOptions<FacebookOptions>, ConfigureDefaults<FacebookOptions>>()
                .AddFacebookAuthentication()
                .AddSingleton<IConfiguration>(config);
            var sp = services.BuildServiceProvider();

            var options = sp.GetRequiredService<IOptionsSnapshot<FacebookOptions>>().Get(FacebookDefaults.AuthenticationScheme);
            Assert.Equal("<id>", options.AppId);
            Assert.Equal("<secret>", options.AppSecret);
            Assert.Equal("<authEndpoint>", options.AuthorizationEndpoint);
            Assert.Equal(new TimeSpan(0, 0, 0, 30), options.BackchannelTimeout);
            //Assert.Equal("/callbackpath", options.CallbackPath); // NOTE: PathString doesn't convert
            Assert.Equal("<issuer>", options.ClaimsIssuer);
            Assert.Equal("<id>", options.ClientId);
            Assert.Equal("<secret>", options.ClientSecret);
            Assert.Equal(new TimeSpan(0, 0, 0, 30), options.RemoteAuthenticationTimeout);
            Assert.True(options.SaveTokens);
            Assert.True(options.SendAppSecretProof);
            Assert.Equal("<signIn>", options.SignInScheme);
            Assert.Equal("<tokenEndpoint>", options.TokenEndpoint);
            Assert.Equal("<userEndpoint>", options.UserInformationEndpoint);
        }

        [Fact]
        public void AddWithDelegateIgnoresConfig()
        {
            var dic = new Dictionary<string, string>
            {
                {"Facebook:AppId", "<id>"},
            };
            var configurationBuilder = new ConfigurationBuilder();
            configurationBuilder.AddInMemoryCollection(dic);
            var config = configurationBuilder.Build();
            var services = new ServiceCollection().AddFacebookAuthentication(o => o.SaveTokens = false).AddSingleton<IConfiguration>(config);
            var sp = services.BuildServiceProvider();

            var options = sp.GetRequiredService<IOptionsSnapshot<FacebookOptions>>().Get(FacebookDefaults.AuthenticationScheme);
            Assert.Null(options.AppId);
            Assert.False(options.SaveTokens);
        }

        [Fact]
        public async Task ThrowsIfAppIdMissing()
        {
            var server = CreateServer(
                app => { },
                services => services.AddFacebookAuthentication(o => o.SignInScheme = "Whatever"),
                context =>
                {
                    // REVIEW: Gross.
                    Assert.Throws<ArgumentException>("AppId", () => context.ChallengeAsync("Facebook").GetAwaiter().GetResult());
                    return true;
                });
            var transaction = await server.SendAsync("http://example.com/challenge");
            Assert.Equal(HttpStatusCode.OK, transaction.Response.StatusCode);
        }

        [Fact]
        public async Task ThrowsIfAppSecretMissing()
        {
            var server = CreateServer(
                app => { },
                services => services.AddFacebookAuthentication(o => o.AppId = "Whatever"),
                context =>
                {
                    // REVIEW: Gross.
                    Assert.Throws<ArgumentException>("AppSecret", () => context.ChallengeAsync("Facebook").GetAwaiter().GetResult());
                    return true;
                });
            var transaction = await server.SendAsync("http://example.com/challenge");
            Assert.Equal(HttpStatusCode.OK, transaction.Response.StatusCode);
        }

        [Fact]
        public async Task ChallengeWillTriggerApplyRedirectEvent()
        {
            var server = CreateServer(
                app =>
                {
                    app.UseAuthentication();
                },
                services =>
                {
                    services.AddAuthentication(options =>
                    {
                        options.DefaultSignInScheme = "External";
                        options.DefaultAuthenticateScheme = "External";
                    });
                    services.AddCookieAuthentication("External", o => { });
                    services.AddFacebookAuthentication(o =>
                    {
                        o.AppId = "Test App Id";
                        o.AppSecret = "Test App Secret";
                        o.Events = new OAuthEvents
                        {
                            OnRedirectToAuthorizationEndpoint = context =>
                            {
                                context.Response.Redirect(context.RedirectUri + "&custom=test");
                                return Task.FromResult(0);
                            }
                        };
                    });
                },
                context =>
                {
                    // REVIEW: Gross.
                    context.ChallengeAsync("Facebook").GetAwaiter().GetResult();
                    return true;
                });
            var transaction = await server.SendAsync("http://example.com/challenge");
            Assert.Equal(HttpStatusCode.Redirect, transaction.Response.StatusCode);
            var query = transaction.Response.Headers.Location.Query;
            Assert.Contains("custom=test", query);
        }

        [Fact]
        public async Task NestedMapWillNotAffectRedirect()
        {
            var server = CreateServer(app => app.Map("/base", map =>
            {
                map.UseAuthentication();
                map.Map("/login", signoutApp => signoutApp.Run(context => context.ChallengeAsync("Facebook", new AuthenticationProperties() { RedirectUri = "/" })));
            }),
            services =>
            {
                services.AddCookieAuthentication("External", o => { });
                services.AddFacebookAuthentication(o =>
                {
                    o.AppId = "Test App Id";
                    o.AppSecret = "Test App Secret";
                    o.SignInScheme = "External";
                });
            },
            handler: null);

            var transaction = await server.SendAsync("http://example.com/base/login");
            Assert.Equal(HttpStatusCode.Redirect, transaction.Response.StatusCode);
            var location = transaction.Response.Headers.Location.AbsoluteUri;
            Assert.Contains("https://www.facebook.com/v2.6/dialog/oauth", location);
            Assert.Contains("response_type=code", location);
            Assert.Contains("client_id=", location);
            Assert.Contains("redirect_uri=" + UrlEncoder.Default.Encode("http://example.com/base/signin-facebook"), location);
            Assert.Contains("scope=", location);
            Assert.Contains("state=", location);
        }

        [Fact]
        public async Task MapWillNotAffectRedirect()
        {
            var server = CreateServer(
                app =>
                {
                    app.UseAuthentication();
                    app.Map("/login", signoutApp => signoutApp.Run(context => context.ChallengeAsync("Facebook", new AuthenticationProperties() { RedirectUri = "/" })));
                },
                services =>
                {
                    services.AddCookieAuthentication("External", o => { });
                    services.AddFacebookAuthentication(o =>
                    {
                        o.AppId = "Test App Id";
                        o.AppSecret = "Test App Secret";
                        o.SignInScheme = "External";
                    });
                },
                handler: null);
            var transaction = await server.SendAsync("http://example.com/login");
            Assert.Equal(HttpStatusCode.Redirect, transaction.Response.StatusCode);
            var location = transaction.Response.Headers.Location.AbsoluteUri;
            Assert.Contains("https://www.facebook.com/v2.6/dialog/oauth", location);
            Assert.Contains("response_type=code", location);
            Assert.Contains("client_id=", location);
            Assert.Contains("redirect_uri="+ UrlEncoder.Default.Encode("http://example.com/signin-facebook"), location);
            Assert.Contains("scope=", location);
            Assert.Contains("state=", location);
        }

        [Fact]
        public async Task ChallengeWillTriggerRedirection()
        {
            var server = CreateServer(
                app => app.UseAuthentication(),
                services =>
                {
                    services.AddAuthentication(options =>
                    {
                        options.DefaultSignInScheme = "External";
                    });
                    services.AddCookieAuthentication();
                    services.AddFacebookAuthentication(o =>
                    {
                        o.AppId = "Test App Id";
                        o.AppSecret = "Test App Secret";
                    });
                },
                context =>
                {
                    // REVIEW: gross
                    context.ChallengeAsync("Facebook").GetAwaiter().GetResult();
                    return true;
                });
            var transaction = await server.SendAsync("http://example.com/challenge");
            Assert.Equal(HttpStatusCode.Redirect, transaction.Response.StatusCode);
            var location = transaction.Response.Headers.Location.AbsoluteUri;
            Assert.Contains("https://www.facebook.com/v2.6/dialog/oauth", location);
            Assert.Contains("response_type=code", location);
            Assert.Contains("client_id=", location);
            Assert.Contains("redirect_uri=", location);
            Assert.Contains("scope=", location);
            Assert.Contains("state=", location);
        }

        [Fact]
        public async Task CustomUserInfoEndpointHasValidGraphQuery()
        {
            var customUserInfoEndpoint = "https://graph.facebook.com/me?fields=email,timezone,picture";
            var finalUserInfoEndpoint = string.Empty;
            var stateFormat = new PropertiesDataFormat(new EphemeralDataProtectionProvider(NullLoggerFactory.Instance).CreateProtector("FacebookTest"));
            var server = CreateServer(
                app =>
                {
                    app.UseAuthentication();
                },
                services =>
                {
                    services.AddAuthentication(options =>
                    {
                        options.DefaultSignInScheme = CookieAuthenticationDefaults.AuthenticationScheme;
                        options.DefaultAuthenticateScheme = CookieAuthenticationDefaults.AuthenticationScheme;
                    });
                    services.AddCookieAuthentication();
                    services.AddFacebookAuthentication(o => 
                    {
                        o.AppId = "Test App Id";
                        o.AppSecret = "Test App Secret";
                        o.StateDataFormat = stateFormat;
                        o.UserInformationEndpoint = customUserInfoEndpoint;
                        o.BackchannelHttpHandler = new TestHttpMessageHandler
                        {
                            Sender = req =>
                            {
                                if (req.RequestUri.GetComponents(UriComponents.SchemeAndServer | UriComponents.Path, UriFormat.UriEscaped) == FacebookDefaults.TokenEndpoint)
                                {
                                    var res = new HttpResponseMessage(HttpStatusCode.OK);
                                    var graphResponse = JsonConvert.SerializeObject(new
                                    {
                                        access_token = "TestAuthToken"
                                    });
                                    res.Content = new StringContent(graphResponse, Encoding.UTF8);
                                    return res;
                                }
                                if (req.RequestUri.GetComponents(UriComponents.SchemeAndServer | UriComponents.Path, UriFormat.UriEscaped) ==
                                    new Uri(customUserInfoEndpoint).GetComponents(UriComponents.SchemeAndServer | UriComponents.Path, UriFormat.UriEscaped))
                                {
                                    finalUserInfoEndpoint = req.RequestUri.ToString();
                                    var res = new HttpResponseMessage(HttpStatusCode.OK);
                                    var graphResponse = JsonConvert.SerializeObject(new
                                    {
                                        id = "TestProfileId",
                                        name = "TestName"
                                    });
                                    res.Content = new StringContent(graphResponse, Encoding.UTF8);
                                    return res;
                                }
                                return null;
                            }
                        };
                    });
                },
                handler: null);

            var properties = new AuthenticationProperties();
            var correlationKey = ".xsrf";
            var correlationValue = "TestCorrelationId";
            properties.Items.Add(correlationKey, correlationValue);
            properties.RedirectUri = "/me";
            var state = stateFormat.Protect(properties);
            var transaction = await server.SendAsync(
                "https://example.com/signin-facebook?code=TestCode&state=" + UrlEncoder.Default.Encode(state),
                $".AspNetCore.Correlation.Facebook.{correlationValue}=N");
            Assert.Equal(HttpStatusCode.Redirect, transaction.Response.StatusCode);
            Assert.Equal("/me", transaction.Response.Headers.GetValues("Location").First());
            Assert.Equal(1, finalUserInfoEndpoint.Count(c => c == '?'));
            Assert.Contains("fields=email,timezone,picture", finalUserInfoEndpoint);
            Assert.Contains("&access_token=", finalUserInfoEndpoint);
        }

        private static TestServer CreateServer(Action<IApplicationBuilder> configure, Action<IServiceCollection> configureServices, Func<HttpContext, bool> handler)
        {
            var builder = new WebHostBuilder()
                .Configure(app =>
                {
                    configure?.Invoke(app);
                    app.Use(async (context, next) =>
                    {
                        if (handler == null || !handler(context))
                        {
                            await next();
                        }
                    });
                })
                .ConfigureServices(configureServices);
            return new TestServer(builder);
        }
    }
}