FoxTube/FoxTube.Core/Services/UserService.cs

using Google.Apis.Auth.OAuth2;
using Google.Apis.Oauth2.v2;
using System;
using System.Threading.Tasks;
using Windows.Security.Authentication.Web;
using YouTube.Authorization;
using Windows.Security.Credentials;
using FoxTube.Models;
using YouTube;
using System.Threading;
using Google.Apis.YouTube.v3;
using Windows.UI.Xaml.Controls;
using FoxTube.Utils;
using YoutubeExplode;
using System.Linq;
using Newtonsoft.Json;
using Google.Apis.Oauth2.v2.Data;

namespace FoxTube.Services
{
	public static class UserService
	{
		public const int MaxUsersCount = 1;

		#region Private members
		private static readonly ExtendedYouTubeService _defaultService = new ExtendedYouTubeService(new Google.Apis.Services.BaseClientService.Initializer
		{
			ApplicationName = "FoxTube",
			ApiKey = SecretConstants.YoutubeApiKey,	// TODO: Replace with an actual API key
		});
		private static readonly YoutubeClient _defaultYtClient = new YoutubeClient();

		private static string[] Scopes { get; } = new string[]
		{
			Oauth2Service.Scope.UserinfoProfile,
			Oauth2Service.Scope.UserinfoEmail,
			YouTubeService.Scope.YoutubeForceSsl
		};

		private static ClientSecrets[] ClientSecrets { get; } = SecretConstants.ClientSecrets;
		#endregion

		public static Userinfoplus[] Users { get; private set; } = new Userinfoplus[MaxUsersCount];

		public static bool IncognitoMode { get; set; } = false;

		public static bool CanAddAccounts => Users.Any(i => i == null);
		public static User CurrentUser { get; set; }
		public static bool Authorized => CurrentUser != null;
		public static ExtendedYouTubeService Service
		{
			get
			{
				if (IncognitoMode || CurrentUser == null)
					return _defaultService;
				else
					return CurrentUser.Service;
			}
		}
		public static YoutubeClient YouTubeClient
		{
			get
			{
				if (IncognitoMode || CurrentUser == null)
					return _defaultYtClient;
				else
					return CurrentUser.Client;
			}
		}

		public static event EventHandler<bool> UserStateUpdated;
		public static event EventHandler<Subscription> SubscriptionsChanged;

		public static async Task<bool> AddUser()
		{
			int queueIndex = Users.ToList().FindIndex(i => i == null);

			if (queueIndex < 0)
				throw new StackOverflowException("The maximum accounts limit is reached");

			ClientSecrets secrets = ClientSecrets[queueIndex];

			Uri requestString = AuthorizationHelpers.FormQueryString(secrets, Scopes);

			WebAuthenticationResult result = await WebAuthenticationBroker.AuthenticateAsync(WebAuthenticationOptions.UseTitle, requestString, AuthorizationHelpers.Endpoint);
			switch (result.ResponseStatus)
			{
				case WebAuthenticationStatus.Success:
					string successCode = AuthorizationHelpers.ParseSuccessCode(result.ResponseData);

					YouTube.Authorization.UserCredential credential = await AuthorizationHelpers.ExchangeToken(secrets, successCode);

					await LoadUser(credential, queueIndex);
					return true;
				case WebAuthenticationStatus.UserCancel:
					break;
				case WebAuthenticationStatus.ErrorHttp:
					await new ContentDialog
					{
						Title = "Something went wrong...",
						Content = "It may be a bug or temporary server issues. Please, try again later"
					}.ShowAsync();

					Metrics.SendReport(new Exception("Authorization failed (HTTP Error)"), null,
						("Response status", result.ResponseStatus.ToString()),
						("Response data", result.ResponseData),
						("Error details", result.ResponseErrorDetail.ToString()));
					break;
			}

			return false;
		}

		public static async Task Initialize()
		{
			Users = JsonConvert.DeserializeObject<Userinfoplus[]>(StorageService.UserInfos ?? "") ?? new Userinfoplus[MaxUsersCount];
			int? lastUserIndex = StorageService.LastUserIndex;

			if (lastUserIndex.HasValue && Users[lastUserIndex.Value] != null ||
				(lastUserIndex = Users.ToList().FindIndex(i => i != null)) > -1)
				await SwitchUser(lastUserIndex.Value);
		}

		public static async Task<bool> Logout()
		{
			if (CurrentUser?.UserInfo?.Id == null)
				return false;

			try
			{
				string userId = CurrentUser.UserInfo.Id;

				PasswordVault passwordVault = new PasswordVault();
				try
				{
					PasswordCredential credential = passwordVault.Retrieve("foxtube", userId);
					passwordVault.Remove(credential);
				}
				catch { }

				await CurrentUser.Credential.RevokeTokenAsync(CancellationToken.None);

				CurrentUser = null;
				Users[Users.ToList().FindIndex(i => i.Id == userId)] = null;

				StorageService.UserInfos = JsonConvert.SerializeObject(Users);
				StorageService.LastUserIndex = null;

				if (Users.Any(i => i != null))
					await SwitchUser(Users.ToList().FindIndex(i => i != null));
				else
					UserStateUpdated?.Invoke(Users, false);

				return true;
			}
			catch (Exception e)
			{
				Metrics.SendReport(new Exception("Failed to logout", e));

				await new ContentDialog
				{
					Title = "Something went wrong...",
					Content = "It may be a bug or temporary server issues. Please, try again later"
				}.ShowAsync();

				return false;
			}
		}

		public static async Task<bool> SwitchUser(int userIndex)
		{
			Userinfoplus userInfo = Users[userIndex];

			PasswordVault valut = new PasswordVault();
			try
			{
				PasswordCredential vaultCredential = valut.Retrieve("foxtube", userInfo.Id);

				vaultCredential.RetrievePassword();
				string token = vaultCredential.Password;
				YouTube.Authorization.UserCredential credential = await AuthorizationHelpers.RestoreUser(ClientSecrets[userIndex], token);

				await LoadUser(credential, userIndex);

				return true;
			}
			catch
			{
				return false;
			}
		}

		private static async Task LoadUser(YouTube.Authorization.UserCredential credential, int userIndex)
		{
			CurrentUser = await User.GetUser(credential);
			Users[userIndex] = CurrentUser.UserInfo;

			StorageService.UserInfos = JsonConvert.SerializeObject(Users);
			StorageService.LastUserIndex = userIndex;

			credential.RefreshTokenUpdated += (s, e) => UpdateToken(CurrentUser.UserInfo.Id, credential.Token.RefreshToken);
			UpdateToken(CurrentUser.UserInfo.Id, credential.Token.RefreshToken);

			UserStateUpdated?.Invoke(Users, true);
		}

		private static void UpdateToken(string id, string refreshToken)
		{
			PasswordVault passwordVault = new PasswordVault();
			try
			{
				PasswordCredential vaultCredential = passwordVault.Retrieve("foxtube", id);
				vaultCredential.Password = refreshToken;
			}
			catch
			{
				PasswordCredential vaultCredential = new PasswordCredential("foxtube", CurrentUser.UserInfo.Id, refreshToken);
				passwordVault.Add(vaultCredential);
			}
		}

		internal static void SubscriptionsChangedInvoker(User sender, Subscription subscription) =>
			SubscriptionsChanged?.Invoke(sender, subscription);
	}
}