sharee.bike-App/TINKLib/ViewModel/Login/LoginPageViewModel.cs

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Linq;
using System.Threading.Tasks;
using System.Windows.Input;
using Plugin.Connectivity;
using Serilog;
using TINK.Model;
using TINK.Model.User;
using TINK.Model.User.Account;
using TINK.MultilingualResources;
using TINK.Repository.Exception;
using TINK.View;
using TINK.ViewModel.Map;
using Xamarin.Forms;

namespace TINK.ViewModel
{
	public class LoginPageViewModel : INotifyPropertyChanged
	{
		/// <summary>
		/// Reference on view service to show modal notifications and to perform navigation.
		/// </summary>
		private readonly IViewService m_oViewService;

		/// <summary> Reference on the tink app instance. </summary>
		private ITinkApp TinkApp { get; }

		/// <summary>
		/// Holds the mail address candidate being entered by user.
		/// </summary>
		private string m_strMailAddress;

		/// <summary>
		/// Holds the password candidate being entered by user.
		/// </summary>
		private string m_strPassword;

		private bool m_bMailAndPasswordCandidatesOk = false;

		/// <summary> Holds a reference to the external trigger service. </summary>
		private Action<string> OpenUrlInExternalBrowser { get; }

		/// <summary>
		/// Event which notifies clients about changed properties.
		/// </summary>
		public event PropertyChangedEventHandler PropertyChanged;

		/// <summary> Used to block more than on copri requests at a given time.</summary>
		private bool isIdle = true;

		/// <summary>
		/// True if any action can be performed (login etc.)
		/// </summary>
		public virtual bool IsIdle
		{
			get => isIdle;
			set
			{
				if (value == isIdle)
					return;

				Log.ForContext<LoginPageViewModel>().Debug($"Switch value of {nameof(IsIdle)} to {value}.");
				isIdle = value;
				PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(nameof(IsIdle)));
				PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(nameof(IsProcessWithRunningProcessView)));
			}
		}

		public bool IsProcessWithRunningProcessView => !isIdle;

		/// <summary> Holds info about current action. </summary>
		private string statusInfoText;

		/// <summary> Holds info about current action. </summary>
		public string StatusInfoText
		{
			get => statusInfoText;
			set
			{
				if (value == statusInfoText)
					return;

				Log.ForContext<LoginPageViewModel>().Debug($"Switch value of {nameof(StatusInfoText)} to {value}.");
				statusInfoText = value;
				PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(nameof(StatusInfoText)));
			}
		}

		/// <summary>
		/// 
		/// </summary>
		/// <param name="p_oSetCredentials">Delegate to set new mail address and password to model.</param>
		/// <param name="p_oUser">Mail address of user if login succeeded.</param>
		/// <param name="openUrlInExternalBrowser">Action to open an external browser.</param>
		/// <param name="p_oViewService">Interface to actuate methods on GUI.</param>
		/// <param name="p_oNavigation">Interface to navigate.</param>
		public LoginPageViewModel(
			ITinkApp tinkApp,
			Action<string> openUrlInExternalBrowser,
			IViewService p_oViewService)
		{
			TinkApp = tinkApp
				?? throw new ArgumentException("Can not instantiate map page view model- object. No tink app object available.");

			OpenUrlInExternalBrowser = openUrlInExternalBrowser
				?? throw new ArgumentException("Can not instantiate login page view model- object. No user external browse service available.");

			m_oViewService = p_oViewService
				?? throw new ArgumentException("Can not instantiate login page view model- object. No view available.");

			m_strMailAddress = tinkApp.ActiveUser.Mail;
			m_strPassword = tinkApp.ActiveUser.Password;

			IsRegisterTargetsInfoVisible = new List<string> { Model.Services.CopriApi.ServerUris.CopriServerUriList.TINK_LIVE, Model.Services.CopriApi.ServerUris.CopriServerUriList.TINK_DEVEL }.Contains(tinkApp.Uris.ActiveUri.AbsoluteUri);

			tinkApp.ActiveUser.StateChanged += OnStateChanged;
		}

		/// <summary>
		/// Login state changed.
		/// </summary>
		/// <param name="p_oSender"></param>
		/// <param name="p_oEventArgs"></param>
		private void OnStateChanged(object p_oSender, EventArgs p_oEventArgs)
		{
			var l_oPropertyChanged = PropertyChanged;
			if (l_oPropertyChanged != null)
			{
				l_oPropertyChanged(this, new PropertyChangedEventArgs(nameof(IsLoggedOut)));
				l_oPropertyChanged(this, new PropertyChangedEventArgs(nameof(IsLoginRequestAllowed)));
				l_oPropertyChanged(this, new PropertyChangedEventArgs(nameof(MailAddress)));
				l_oPropertyChanged(this, new PropertyChangedEventArgs(nameof(Password)));
			}
		}

		/// <summary> Gets a value indicating whether user is logged out or not.</summary>
		public bool IsLoggedOut { get { return !TinkApp.ActiveUser.IsLoggedIn; } }

		/// <summary> Gets a value indicating whether user can try to login.</summary>
		public bool IsLoginRequestAllowed
		{
			get
			{
				return !TinkApp.ActiveUser.IsLoggedIn
					&& m_bMailAndPasswordCandidatesOk;
			}
		}

		/// <summary> Gets mail address of user.</summary>
		public string MailAddress
		{
			get
			{
				return m_strMailAddress;
			}

			set
			{
				m_strMailAddress = value;
				UpdateAndFireIfRequiredOnEnteringMailOrPwd();
			}
		}

		/// <summary> Gets password user.</summary>
		public string Password
		{
			get
			{
				return m_strPassword;
			}

			set
			{
				m_strPassword = value;
				UpdateAndFireIfRequiredOnEnteringMailOrPwd();
			}
		}

		/// <summary>Update on password or mailaddress set. </summary>
		private void UpdateAndFireIfRequiredOnEnteringMailOrPwd()
		{
			var l_bLastMailAndPasswordCandidatesOk = m_bMailAndPasswordCandidatesOk;

			m_bMailAndPasswordCandidatesOk = Validator.ValidateMailAndPasswordDelegate(MailAddress, Password).ValidElement == Elements.Account;

			if (m_bMailAndPasswordCandidatesOk != l_bLastMailAndPasswordCandidatesOk)
			{
				PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(nameof(IsLoginRequestAllowed)));
			}
		} 

		/// <summary>
		/// Command object to bind login button to view model.
		/// </summary>
		public ICommand OnLoginRequest
		{
			get
			{
				return new Command(async () => await Login());
			}
		}

		/// <summary> Processes request to register a new user. </summary>
		public ICommand OnRegisterRequest => new Command(async () =>
		{
			if (CrossConnectivity.Current.IsConnected)
			{
				await m_oViewService.PushAsync(ViewTypes.RegisterPage);
			}
			else
			{
				await m_oViewService.DisplayAlert(
					AppResources.MessageHintTitle,
					AppResources.ErrorNoWeb,
					AppResources.MessageAnswerOk);
			}
		});

		/// <summary> Processes request to recover password. </summary>
		public ICommand OnPasswordForgottonRequest => new Command(async () =>
		{
			if (CrossConnectivity.Current.IsConnected)
			{
				await m_oViewService.PushAsync(ViewTypes.PasswordForgottenPage);
			}
			else
			{
				await m_oViewService.DisplayAlert(
					AppResources.MessageHintTitle,
					AppResources.ErrorNoWeb,
					AppResources.MessageAnswerOk);
			}
		});

		/// <summary>
		/// User request to log in.
		/// </summary>
		public async Task Login()
		{
			if (!IsLoginRequestAllowed)
			{
				if(TinkApp.ActiveUser.IsLoggedIn)
				{
					await m_oViewService.DisplayAlert(
						AppResources.ErrorLoginTitle,
						string.Format(AppResources.ErrorLoginAlreadyLoggedIn,TinkApp.ActiveUser.Mail),
						AppResources.MessageAnswerOk);
				}
				else if (!m_bMailAndPasswordCandidatesOk)
				{ 
					await m_oViewService.DisplayAlert(
						AppResources.ErrorLoginTitle,
						AppResources.ErrorLoginInvalidMailOrPasswortInput,
						AppResources.MessageAnswerOk);
				}
				return;
			}
			else
			{
				IsIdle = false;
				StatusInfoText = AppResources.ActivityTextOneMomentPlease;
				IAccount account = new EmptyAccount();
				try
				{
					Log.ForContext<LoginPageViewModel>().Information("User taped login button.");

					try
					{
						TinkApp.ActiveUser.CheckIsPasswordValid(MailAddress, Password);

						// Do login.
						account = await TinkApp.GetConnector(CrossConnectivity.Current.IsConnected).Command.DoLogin(MailAddress, Password, TinkApp.ActiveUser.DeviceId);

						await TinkApp.ActiveUser.Login(account);

						// Update map page filter because user might be of both groups TINK an Konrad.
						TinkApp.GroupFilterMapPage =
							GroupFilterMapPageHelper.CreateUpdated(
								TinkApp.GroupFilterMapPage,
								TinkApp.ActiveUser.DoFilter(TinkApp.FilterGroupSetting.DoFilter()));

						// Update settings page filter because user might be of both groups TINK an Konrad.
						TinkApp.FilterGroupSetting.DoFilter(TinkApp.ActiveUser.Group);

						// Persist new settings.
						TinkApp.Save();

						TinkApp.UpdateConnector();
					}
					catch (InvalidAuthorizationResponseException l_oException)
					{
						// Copri response is invalid.
						Log.ForContext<LoginPageViewModel>().Error("Login failed (invalid. auth. response). {@l_oException}.", l_oException);

						await m_oViewService.DisplayAlert(
							AppResources.ErrorLoginTitle,
							AppResources.ErrorLoginInvalidAuthorization,
							AppResources.MessageAnswerOk);

						IsIdle = true;
						StatusInfoText = string.Empty;
						return;
					}
					catch (UnsupportedCopriVersionDetectedException)
					{
						await m_oViewService.DisplayAlert(
							AppResources.ErrorLoginTitle,
							 string.Format(
								 AppResources.MessageAppVersionIsOutdated,
								 TinkApp.Flavor.GetDisplayName()),
							AppResources.MessageAnswerOk);

						IsIdle = true;
						StatusInfoText = string.Empty;
						return;
					}
					catch (Exception l_oException)
					{
						// Copri server is not reachable.
						if (l_oException is WebConnectFailureException)
						{
							Log.ForContext<LoginPageViewModel>().Information("Login failed (web communication exception). {@l_oException}.", l_oException);

							await m_oViewService.DisplayAlert(
								AppResources.ErrorNoConnectionTitle,
								AppResources.ErrorNoWeb,
								AppResources.MessageAnswerOk);
						}
						else if (l_oException is UsernamePasswordInvalidException)
						{
							// Cookie is empty.
							Log.ForContext<LoginPageViewModel>().Error("Login failed (empty cookie). {@l_oException}.", l_oException);
							await m_oViewService.DisplayAlert(
								AppResources.ErrorLoginTitle,
								string.Format(AppResources.ErrorLoginNoCookie, l_oException.Message),
								AppResources.MessageAnswerOk);
						}
						else
						{
							Log.ForContext<LoginPageViewModel>().Error("Login failed. {@l_oException}.", l_oException);
							await m_oViewService.DisplayAlert(
								AppResources.ErrorLoginTitle,
								l_oException.Message,
								AppResources.MessageAnswerOk);
						}

						IsIdle = true;
						StatusInfoText = string.Empty;
						return;
					}

					// Display information that login succeeded.
					Log.ForContext<LoginPageViewModel>().Information("Login succeeded. {@tinkApp.ActiveUser}.", TinkApp.ActiveUser);

					var title = TinkApp.ActiveUser.Group.Intersect(new List<string> { Model.Connector.FilterHelper.CARGOBIKE, Model.Connector.FilterHelper.CITYBIKE }).Any()
						? string.Format(AppResources.MessageLoginWelcomeTitleGroup, TinkApp.ActiveUser.GetUserGroupDisplayName())
						: string.Format(AppResources.MessageLoginWelcomeTitle);

					await m_oViewService.DisplayAlert(
						title,
						string.Format(AppResources.MessageLoginWelcome, TinkApp.ActiveUser.Mail),
						AppResources.MessageAnswerOk);

					//clear MailAdress and Password user input
					MailAddress = string.Empty;
					Password = string.Empty;
				}
				catch (Exception p_oException)
				{
					Log.ForContext<LoginPageViewModel>().Error("An unexpected error occurred displaying log out page. {@Exception}", p_oException);

					IsIdle = true;
					StatusInfoText = string.Empty;
					return;
				}

				try
				{
					if (!TinkApp.ActiveUser.Group.Contains(Model.Connector.FilterHelper.CARGOBIKE))
					{
						// No need to show "Anleitung TINK Räder" because user can not use tink.
						await m_oViewService.ShowPage("//MapPage");
						IsIdle = true;
						StatusInfoText = string.Empty;
						return;
					}

					// Switch to map page
					await m_oViewService.ShowPage("//MapPage");
				}
				catch (Exception p_oException)
				{
					Log.ForContext<LoginPageViewModel>().Error("Ein unerwarteter Fehler ist auf der Seite Anleitung TINK Räder (nach Anmeldeseite) aufgetreten. {@Exception}", p_oException);

					IsIdle = true;
					StatusInfoText = string.Empty;
					return;
				}

				IsIdle = true;
				StatusInfoText = string.Empty;
			}
		}

		/// <summary> Holds whether TINK/ Copri info is shown.</summary>
		public bool IsRegisterTargetsInfoVisible { get; private set; }

		/// <summary> Text providing info about TINK/ konrad registration. </summary>
		public FormattedString RegisterTargetsInfo
		{
			get
			{
				var l_oHint = new FormattedString();
				l_oHint.Spans.Add(new Span { Text = AppResources.MarkingLoginInstructionsTinkKonradTitle });
				l_oHint.Spans.Add(new Span { Text = AppResources.MarkingLoginInstructionsTinkKonradMessage });

				return l_oHint;
			}
		}

		/// <summary> Opens login page.</summary>
		public void RegisterRequest(string url)
		{
			try
			{
				OpenUrlInExternalBrowser(url);
			}
			catch (Exception p_oException)
			{
				Log.Error("Ein unerwarteter Fehler ist auf der Login Seite beim Öffnen eines Browsers, Seite {url}, aufgetreten. {@Exception}", url, p_oException);
				return;
			}
		}
	}
}