using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;
using Comal.Classes;
using InABox.Clients;
using InABox.Configuration;
using InABox.Core;
using InABox.Mobile;
using InABox.Rpc;
using Xamarin.Essentials;
using Xamarin.Forms;
using XF.Material.Forms.UI;
using XF.Material.Forms.UI.Dialogs;

namespace comal.timesheets
{
    public partial class PinLoginPage : ContentPage
    {

        private enum SubPage
        {
            Autologin,
            Pin,
            TwoFactor,
            Password
        }
        
        private SubPage _page;
        private String _pin = "";
        private String _2fa = "";
        
        private DatabaseSettings _settings { get; set; }
        
        public PinLoginPage()
        {
            InitializeComponent();
            SelectSubPage(SubPage.Autologin);
        }
        
        protected override async void OnAppearing()
        {
            MobileLogging.Log("PINLoginPage.Appearing()");
            base.OnAppearing();
            
            // IS there a new version?  If so, then get that before doing anything else
            MobileLogging.Log("PINLoginPage.CheckForLatestVersion()");
            CheckForLatestVersion();

            //TODO this is only for the temporary site app login - needs to be removed
            SelectSubPage(SubPage.Autologin);

            // Is this the first time through?
            // If so, then try to validate         
            if (_page == SubPage.Autologin)
            {
                
                MobileLogging.Log("PINLoginPage.CheckAutoConfigurationLink()");
                CheckAutoConfigurationLink();
                
                MobileLogging.Log("PINLoginPage.LoadSettings()");
                LoadSettings();

                MobileLogging.Log("PINLoginPage.Connecting()");
                TransportStatus connection = TransportStatus.None;
                using (await MaterialDialog.Instance.LoadingDialogAsync(message: "Connecting"))
                {
                    await Task.Run(() =>
                    {
                        connection = App.ConnectTransport(_settings.URLs);
                    });
                    
                }
                
                if (connection != TransportStatus.OK)
                {
                    await DisplayAlert("Connection Error", $"Unable to establish a connection!\n\nERR: {connection}", "OK");
                    Navigation.PushAsync(new SettingsPage());
                    return;
                }

                MobileLogging.Log("PINLoginPage.AutoLogin()");
                ValidationStatus status = ValidationStatus.INVALID;
                using (await MaterialDialog.Instance.LoadingDialogAsync(message: "Validating"))
                {
                    Task.Run(() => { status = AutoLogin(); }).Wait();
                }

                if (status == ValidationStatus.VALID)
                {
                    MobileLogging.Log("PINLoginPage.CheckPasswordExpiration()");
                    if (await CheckPasswordExpiration())
                    {
                        PasswordCancelColumn.Width = new GridLength(1, GridUnitType.Star);
                        SelectSubPage(SubPage.Password);
                    }
                    else
                    {
                        MobileLogging.Log("PINLoginPage.LaunchMainPage()");
                        LaunchMainPage();
                    }
                }

                else if (status == ValidationStatus.INVALID)
                {
                    
                    // If we _should_ have been able to log in (ie we have a username)
                    // show an error message.  Otherwise, jump to the PIN page
                    if (!String.IsNullOrWhiteSpace(_settings.UserID))
                        await DisplayAlert("Error logging in", "Invalid User ID, Password or PIN", "OK");
                    
                    MobileLogging.Log("PINLoginPage.SelectSubPage(SubPage.Pin)");
                    SelectSubPage(SubPage.Pin);
                }
                
                else if (status == ValidationStatus.REQUIRE_2FA)
                {
                    MobileLogging.Log("PINLoginPage.SelectSubPage(SubPage.TwoFactor)");
                    SelectSubPage(SubPage.TwoFactor);
                }
                
                else if (status == ValidationStatus.PASSWORD_EXPIRED)
                {
                    MobileLogging.Log("PINLoginPage.SelectSubPage(SubPage.Password)");
                    await DisplayAlert("Alert", "Your password has expired - please change it", "OK");
                    PasswordCancelColumn.Width = new GridLength(0, GridUnitType.Absolute);
                    SelectSubPage(SubPage.Password);
                }
            }
            
            else if (_page == SubPage.Pin)
            {
                UpdatePIN('\0');
            }
            
            else if (_page == SubPage.TwoFactor)
            {
                // Has the user left the app to go and get the 2fa code from sms or google authenticator?
                // If so, then try to retrieve the 2fa code from the clipboard
                var text = Clipboard.GetTextAsync().Result;
                if ((text?.Length == 6) && (text?.All(Char.IsDigit) == true))
                {
                    _2fa = text;
                    TwoFA0.Text = text.Substring(0, 1);
                    TwoFA1.Text = text.Substring(1, 1);
                    TwoFA2.Text = text.Substring(2, 1);
                    TwoFA3.Text = text.Substring(3, 1);
                    TwoFA4.Text = text.Substring(4, 1);
                    TwoFA5.Text = text.Substring(5, 1);
                }
                else
                    UpdateTwoFA('\0');
            }
            else if (_page == SubPage.Password)
            {
                NewPassword.Text = "";
                NewPassword2.Text = "";
                ChangePasswordButton.IsEnabled = false;
            }
        }
        
        private void CheckAutoConfigurationLink()
        {
            var parameters = App.LaunchParameters;
            App.LaunchParameters = "";
            
            if (String.IsNullOrWhiteSpace(parameters))
                return;
            
            var decrypted = Encryption.Decrypt(parameters, "logindetailslink");
            if (decrypted?.ToUpper()?.Contains("ENDURLS") == true)
            {
                var comps = decrypted.Split("ENDURLS");
                if (comps.Length == 2)
                {
                    var urls = comps.First().Split(',');
                    var settings = comps.Last().Split(',');
                    if (urls.Any() && (settings.Length == 3))
                    {
                        String user = settings[0];
                        String password = settings[1];
                        DateTime expiry = DateTime.Parse(settings[2]);
                        if (expiry > DateTime.Now)
                        {
                            _settings.URLs = urls;
                            _settings.UserID = user;
                            _settings.Password = password;
                            new LocalConfiguration<DatabaseSettings>().Save(_settings);
                            DisplayAlert("Autoconfiguration", "Configuration Updated Successfully!!", "OK").Wait();
                        }
                        DisplayAlert("AutoConfiguration", "AutoConfiguration Link has expired!", "OK").Wait();
                    }
                    DisplayAlert("AutoConfiguration", "Invalid AutoConfiguration content!", "OK").Wait();
                }
                DisplayAlert("AutoConfiguration", "Invalid AutoConfiguration structure!", "OK").Wait();
            }
            DisplayAlert("AutoConfiguration", "Invalid AutoConfiguration format!", "OK").Wait();
            
        }

        private void LoadSettings()
        {
            
            _settings = new LocalConfiguration<DatabaseSettings>().Load();
            _settings.URLs = new String[]
                {
                     "remote.com-al.com.au:8050",
                };
            new LocalConfiguration<DatabaseSettings>().Save(_settings);

            if (!_settings.URLs.Any())
             {
                 // Do we have old-style settings we can migrate from?
                 var Settings = new LocalConfiguration<ConnectionSettings>().Load();
                 if (!String.IsNullOrWhiteSpace(Settings.URL))
                 {
                     _settings.URLs = new string[] { Settings.URL };
                     _settings.UserID = Settings.UserID;
                     _settings.Password = Settings.Password;
                     // Get rid of the old ConnectionSettings storage
                     new LocalConfiguration<ConnectionSettings>().Delete();
                 }
             }

            if (!_settings.URLs.Any())
                _settings.URLs = new String[]
                 {
                     "remote.com-al.com.au:8050",
                 };

            if (string.IsNullOrWhiteSpace(_settings.UserID) || string.IsNullOrWhiteSpace(_settings.Password))
            {               
                Navigation.PushAsync(new SettingsPage());
            }
             
             // Still nothing?  Populate with Defaults
             if (!_settings.URLs.Any())
             {
                 _settings.URLs = new String[]
                 {
                     "remote.com-al.com.au:8050",
                     //"192.168.0.247:8010"
                     //"demo.prsdigital.com.au:8003",
                     //"demo2.prsdigital.com.au:8003",
                     //"demo3.prsdigital.com.au:8003"
                 };
                 //_settings.UserID = "frank";
                 //_settings.Password = "frankvb22";
                 _settings.UserID = "GUEST";
                 _settings.Password = "guest";
                 //_settings.UserID = "ADMIN";
                 //_settings.Password = "admin";
                 new LocalConfiguration<DatabaseSettings>().Save(_settings);
             }

             //TODO - re enable this when this app is not just the site module
             //App.IsSharedDevice = String.IsNullOrWhiteSpace(_settings.UserID);

        }
        
        public ValidationStatus AutoLogin(string pin = "")
        {
            
            ValidationStatus result = ValidationStatus.INVALID;

            Guid sessionID = App.Current.Properties.ContainsKey("SessionID")
                ? Guid.Parse(App.Current.Properties["SessionID"].ToString())
                : Guid.Empty;
            
            if (!Guid.Equals(sessionID, Guid.Empty))
                result = ClientFactory.Validate(sessionID);

            if (result == ValidationStatus.INVALID)
            {
                if (!String.IsNullOrWhiteSpace(_settings.UserID) && !String.IsNullOrWhiteSpace(_settings.Password))
                    result = ClientFactory.Validate(_settings.UserID, _settings.Password);
            }
            
            return result;
            
        }
        
        private async Task<bool> CheckPasswordExpiration()
        {
            if (!ClientFactory.PasswordExpiration.IsEmpty())
            {
                var timeUntilExpiration = ClientFactory.PasswordExpiration - DateTime.Now;
                if (timeUntilExpiration.Days < 14)
                {
                    string chosenOption = await DisplayActionSheet("Alert",
                        $"Password will expire in {timeUntilExpiration.Days} days. Change password now?", null, "Yes", "No");
                    return String.Equals(chosenOption, "Yes");
                }
            }

            return false;
        }

        private async void LaunchMainPage()
        {
            Device.BeginInvokeOnMainThread(() => SelectSubPage(String.IsNullOrWhiteSpace(_settings.UserID) ? SubPage.Pin : SubPage.Autologin));
            using (await MaterialDialog.Instance.LoadingDialogAsync(message: "Starting Up"))  
                App.Data.Setup();
            Navigation.PushAsync(new SiteModule());
        }
        
        private void CheckForLatestVersion()
        {
            Task.Run(async () =>
            {
                try
                {
                    bool isLatest = true;

                    try
                    {
                        isLatest = await MobileUtils.AppVersion.IsUsingLatestVersion();
                    }
                    catch (Exception eLatest)
                    {
                        string s = eLatest.Message;
                    }

                    if (!isLatest)
                    {
                        string latestVersionNumber = await MobileUtils.AppVersion.GetLatestVersionNumber();

                        Device.BeginInvokeOnMainThread(async () =>
                        {
                            string chosenOption = await DisplayActionSheet(String.Format("Version {0} Available. Update now?", latestVersionNumber), "You will be reminded again in 10 minutes.", null, "Yes", "No");
                            switch (chosenOption)
                            {
                                case "No":
                                    break;
                                case "Cancel":
                                    break;
                                case "Yes":
                                    Dispatcher.BeginInvokeOnMainThread(() => { MobileUtils.AppVersion.OpenAppInStore(); });
                                    break;
                                default:
                                    break;
                            }
                        });
                    }
                }
                catch { }
            });
        }

        
        private void SelectSubPage(SubPage page)
        {
            _page = page;
            
            SplashLayout.IsVisible = _page == SubPage.Autologin;
            PINLayout.IsVisible = _page == SubPage.Pin;
            TwoFALayout.IsVisible = _page == SubPage.TwoFactor;
            PasswordLayout.IsEnabled = _page == SubPage.Password;
            
            MasterGrid.ColumnDefinitions[0].Width = _page == SubPage.Autologin 
                ? new GridLength(1, GridUnitType.Star) 
                : new GridLength(0, GridUnitType.Absolute);
            
            MasterGrid.ColumnDefinitions[1].Width = _page == SubPage.Pin 
                ? new GridLength(1, GridUnitType.Star) 
                : new GridLength(0, GridUnitType.Absolute);
            
            MasterGrid.ColumnDefinitions[2].Width = _page == SubPage.TwoFactor 
                ? new GridLength(1, GridUnitType.Star) 
                : new GridLength(0, GridUnitType.Absolute);   
            
            UpdatePIN('\0');
            UpdateTwoFA('\0');
            
            NewPassword.Text = "";
            NewPassword2.Text = "";
            ChangePasswordButton.IsEnabled = false;
            
        }
        
        #region PIN Page
        
        private void UpdatePIN(char digit)
        {
            _pin = digit switch
            {
                '\0' => "",
                '\b' => _pin.Length > 0 ? _pin.Substring(0, _pin.Length - 1) : "",
                _ => String.Concat(_pin, digit)
            };
            Pin0.Text = _pin.Length > 0 ? "*" : "";
            Pin1.Text = _pin.Length > 1 ? "*" : "";
            Pin2.Text = _pin.Length > 2 ? "*" : "";
            Pin3.Text = _pin.Length > 3 ? "*" : "";
            PinBack.IsEnabled = !String.IsNullOrEmpty(_pin);
            PinOK.IsEnabled = _pin?.Length == 4;
        }

        void Pin_Button_Click(object sender, EventArgs args)
        {
            UpdatePIN((sender as Button).Text.ToCharArray().First());
        }
        
        void Pin_Back_Click(object sender, EventArgs args)
        {
            UpdatePIN('\b'); 
        }

        async void Pin_OK_Click(object sender, EventArgs args)
        {
            var status = ClientFactory.Validate(_pin);

            if (status == ValidationStatus.INVALID)
            {
                DisplayAlert("PIN Error", "Invalid PIN Entered!", "OK").Wait();
                UpdatePIN('\0');
            }
            else if (status == ValidationStatus.REQUIRE_2FA)
                SelectSubPage(SubPage.TwoFactor);
            else
                LaunchMainPage();
        }
        
        #endregion
        
        #region Two Factor Page
        
        private void UpdateTwoFA(char digit)
        {
            _2fa = digit switch
            {
                '\0' => "",
                '\b' => _2fa.Length > 0 ? _2fa.Substring(0, _2fa.Length - 1) : "",
                _ => String.Concat(_2fa, digit)
            };
            TwoFA0.Text = _2fa.Length > 0 ? _2fa.Substring(0,1) : "";
            TwoFA1.Text = _2fa.Length > 1 ? _2fa.Substring(1,1) : "";
            TwoFA2.Text = _2fa.Length > 2 ? _2fa.Substring(2,1) : "";
            TwoFA3.Text = _2fa.Length > 3 ? _2fa.Substring(3,1) : "";
            TwoFA4.Text = _2fa.Length > 4 ? _2fa.Substring(4,1) : "";
            TwoFA5.Text = _2fa.Length > 5 ? _2fa.Substring(5,1) : "";
            TwoFABack.IsEnabled = !String.IsNullOrEmpty(_2fa);
            TwoFAOK.IsEnabled = _2fa?.Length == 6;
        }

        void TwoFA_Button_Click(object sender, EventArgs args)
        {
            UpdateTwoFA((sender as Button).Text.ToCharArray().First());
        }
        
        void TwoFA_Back_Click(object sender, EventArgs args)
        {
            UpdateTwoFA('\b'); 
        }

        void TwoFA_OK_Click(object sender, EventArgs args)
        {
            if (ClientFactory.Check2FA(_2fa))
                LaunchMainPage();
            DisplayAlert("2FA Error", "Invalid 2FA Code", "OK").Wait();
            UpdateTwoFA('\0');
        }
        
        #endregion
        
        #region Change Password Page
        
        private void NewPassword_OnTextChanged(object sender, TextChangedEventArgs e)
        {
            ChangePasswordButton.IsEnabled = 
                !String.IsNullOrWhiteSpace(NewPassword.Text)
                && NewPassword.Text.Length >= 5
                && !String.IsNullOrWhiteSpace(NewPassword2.Text)
                && String.Equals(NewPassword.Text, NewPassword2.Text);
        }
        
        private async void ChangePasswordButton_OnClicked(object sender, EventArgs e)
        {
            using (await MaterialDialog.Instance.LoadingDialogAsync(message: "Saving"))
            {
                var user = new User() { ID = ClientFactory.UserGuid };
                user.Password = NewPassword.Text;
                new Client<User>().Save(user, "Password updated by User from Timebench");
                _settings.Password = user.Password;
                new LocalConfiguration<DatabaseSettings>().Save(_settings);
                
                LaunchMainPage();
            }
        }
        
        private void CancelPasswordButton_OnClicked(object sender, EventArgs e)
        {
            LaunchMainPage();
        }
        
        #endregion


        private void Settings_OnClicked(object sender, EventArgs e)
        {
            // Always try autologin when returning from Settings Page
            SelectSubPage(SubPage.Autologin);
            Navigation.PushAsync(new SettingsPage());
        }
        
    }
}