using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Tango.BL;
using Tango.BL.Entities;
using Tango.Integration.Operation;
using Tango.Settings;
using Tango.PPC.Common.Application;
using Tango.Core.DI;
using Tango.PPC.Common;
using System.Windows;
using Tango.Core;
using System.IO;
using Tango.Core.Helpers;
using Tango.PPC.Common.Modules;
using System.Windows.Threading;
using Tango.Transport.Adapters;
using Tango.PMR.Connection;
using Tango.PPC.Common.Connection;
using Tango.SQLExaminer;
using System.Data.SqlClient;
using Tango.BL.Builders;
using Tango.PPC.Common.Threading;
using System.Diagnostics;
using Tango.PPC.Common.EventLogging;
using Tango.BL.Enumerations;
using Tango.PPC.Common.Notifications;
using Tango.PPC.Common.WatchDog;
using Tango.PPC.UI.Dialogs;
using Tango.Core.Threading;
using Tango.PPC.Common.Messages;
using Tango.Core.ExtensionMethods;
using Tango.PPC.Common.Navigation;
using Tango.PPC.Common.Synchronization;
using Tango.Insights;
using System.Threading;
using System.Reflection;
using Tango.PPC.UI.ViewsContracts;

namespace Tango.PPC.UI.PPCApplication
{
    /// <summary>
    /// Represents the default PPC application manager.
    /// </summary>
    /// <seealso cref="Tango.Core.ExtendedObject" />
    /// <seealso cref="Tango.PPC.Common.Application.IPPCApplicationManager" />
    public class DefaultPPCApplicationManager : ExtendedObject, IPPCApplicationManager
    {
        private List<PPCViewModel> _notifiedViewModels;
        private IMachineProvider _machineProvider;
        private Machine _machine;
        private IDispatcherProvider _dispatcher;
        private IEventLogger _eventLogger;
        private IPPCModuleLoader _moduleLoader;
        private INotificationProvider _notificationProvider;
        private IMachineDataSynchronizer _machineDataSynchronizer;
        private WatchDogServer _watchdogServer;
        private ObservablesContext _machineContext;
        private ActionTimer _screenLockTimer;

        /// <summary>
        /// Occurs when a system restart is required.
        /// </summary>
        public event EventHandler SystemRestartRequired;

        /// <summary>
        /// Occurs when the updater utility has failed to perform the last update.
        /// </summary>
        public event EventHandler UpdaterFailed;

        /// <summary>
        /// Occurs when the application has started.
        /// </summary>
        public event EventHandler ApplicationStarted;

        /// <summary>
        /// Occurs when all PPC modules are ready and initialized.
        /// </summary>
        public event EventHandler ModulesInitialized;

        /// <summary>
        /// Occurs when the application is ready and all modules are views are loaded.
        /// </summary>
        public event EventHandler ApplicationReady;

        /// <summary>
        /// Occurs when machine setup is required.
        /// </summary>
        public event EventHandler SetupRequired;

        /// <summary>
        /// Occurs when the main window content has been rendered.
        /// </summary>
        public event EventHandler ContentRendered;

        /// <summary>
        /// Occurs when the application has encountered an error when initializing.
        /// </summary>
        public event EventHandler<Exception> ApplicationInitializationError;

        /// <summary>
        /// Gets a value indicating whether the application is shutting down.
        /// </summary>
        public bool IsShuttingDown { get; private set; }

        private bool _isInTechnicianMode;
        /// <summary>
        /// Gets a value indicating whether the application is in technician mode.
        /// </summary>
        public bool IsInTechnicianMode
        {
            get { return _isInTechnicianMode; }
            set { _isInTechnicianMode = value; RaisePropertyChangedAuto(); }
        }

        /// <summary>
        /// Gets the application version.
        /// </summary>
        public Version Version
        {
            get
            {
                return AssemblyHelper.GetCurrentAssemblyVersion();
            }
        }

        /// <summary>
        /// Gets the application build date.
        /// </summary>
        public String BuildDate
        {
            get
            {
                return AssemblyHelper.GetCurrentAssemblyBuildDate().ToShortDateString();
            }
        }

        /// <summary>
        /// Gets the version tag.
        /// </summary>
        public String VersionTag
        {
            get
            {
                var str = FileVersionInfo.GetVersionInfo(Assembly.GetExecutingAssembly().Location).Comments;
                return str.IsNotNullOrEmpty() ? str : null;

            }
        }

        /// <summary>
        /// Gets the version and tag display.
        /// </summary>
        public String VersionAndTag
        {
            get { return Version.ToString(3) + $"{(VersionTag.IsNotNullOrEmpty() ? $" [{VersionTag}]" : String.Empty)}"; }
        }

        /// <summary>
        /// Gets the application startup date.
        /// </summary>
        public DateTime StartUpDate { get; private set; }

        /// <summary>
        /// Gets a value indicating whether an update has occurred before the application started.
        /// </summary>
        public bool IsAfterUpdate { get; private set; }

        /// <summary>
        /// Gets a value indicating whether the updater utility has failed to perform the last update.
        /// </summary>
        public bool IsUpdateFailed { get; private set; }

        private bool _isScreenLocked;
        /// <summary>
        /// Gets or sets a value indicating whether the screen is currently locked.
        /// </summary>
        public bool IsScreenLocked
        {
            get { return _isScreenLocked; }
            set { _isScreenLocked = value; RaisePropertyChangedAuto(); }
        }

        /// <summary>
        /// Gets the firmware version.
        /// </summary>
        public Version FirmwareVersion
        {
            get
            {
                return Version.Parse(SettingsManager.Default.GetOrCreate<PPCSettings>().FirmwareVersion);
            }
        }

        /// <summary>
        /// Gets or sets the application folder.
        /// </summary>
        public String StartPath { get; private set; }

        /// <summary>
        /// Initializes a new instance of the <see cref="DefaultPPCApplicationManager"/> class.
        /// </summary>
        public DefaultPPCApplicationManager(IMachineProvider machineProvider, IDispatcherProvider dispatcherProvider, IEventLogger eventLogger, IPPCModuleLoader moduleLoader, INotificationProvider notificationProvider, IMachineDataSynchronizer machineDataSynchronizer)
        {
            StartPath = AssemblyHelper.GetCurrentAssemblyFolder();

            _notificationProvider = notificationProvider;
            _machineProvider = machineProvider;
            _dispatcher = dispatcherProvider;
            _eventLogger = eventLogger;
            _moduleLoader = moduleLoader;
            _machineDataSynchronizer = machineDataSynchronizer;

            if (!DesignMode)
            {
                _notifiedViewModels = new List<PPCViewModel>();

                MainWindow.Instance.ContentRendered += (_, __) =>
                {
                    OnMainWindowContentRendered();
                };
            }
        }

        /// <summary>
        /// Called when the main window content has been rendered
        /// </summary>
        private void OnMainWindowContentRendered()
        {
            LogManager.Log("Main window content rendered.");

            ContentRendered?.Invoke(this, new EventArgs());

            StartApplication();
        }

        private async void StartApplication()
        {
            PPCSettings settings = null;

            bool initialized = false;
            bool isAfterSetup = false;

            StartUpDate = DateTime.Now;

            await Task.Factory.StartNew(() =>
            {
                try
                {
                    LogManager.Log("Reading PPC settings...");
                    settings = SettingsManager.Default.GetOrCreate<PPCSettings>();

                    LogManager.Log(settings.ToJsonString());

                    //Start watchdog
                    _watchdogServer = new WatchDogServer(Application.Current.Dispatcher);
#if (!DEBUG && !Eureka)

                    if (settings.EnableWatchDog)
                    {
                        _watchdogServer.Start();
                    }
#endif

                    LogManager.Log("Reading Core settings...");
                    var coreSettings = SettingsManager.Default.GetOrCreate<CoreSettings>();

                    if (!SettingsManager.Default.IsFileExists())
                    {
                        LogManager.Log("Settings file does not exists. creating...");
                        settings.Save();
                    }

                    if (App.StartupArgs.Contains("-update_ok"))
                    {
                        LogManager.Log("Application started with '-update_ok' startup arguments. The application has been successfully updated.");

                        if (settings.ApplicationState == ApplicationStates.PreSetup || settings.ApplicationState == ApplicationStates.FactoryRestore)
                        {
                            isAfterSetup = true;
                            LogManager.Log("System restart is required.");
                        }
                        else
                        {
                            IsAfterUpdate = true;
                        }

                        settings.ApplicationState = ApplicationStates.Ready;
                        settings.Save();

                        if (isAfterSetup)
                        {
                            SystemRestartRequired?.Invoke(this, new EventArgs());
                            return;
                        }
                    }

                    if (App.StartupArgs.Contains("-update_failed"))
                    {
                        LogManager.Log("Application started with '-update_failed' startup arguments. The updater utility has failed.");

                        IsUpdateFailed = true;

                        settings.ApplicationState = ApplicationStates.Ready;
                        settings.Save();
                        UpdaterFailed?.Invoke(this, new EventArgs());
                        return;
                    }

                    if (settings.ApplicationState == ApplicationStates.Ready)
                    {
                        LogManager.Log("Initializing ObservablesStaticCollections...");
                        ObservablesStaticCollections.Instance.Initialize();
                        LogManager.Log("Loading machine from database...");
                        _machineContext = ObservablesContext.CreateDefault();
                        _machine = new MachineBuilder(_machineContext).SetFirst().WithVersion().WithOrganization().WithConfiguration().WithSpools().WithCats().Build();


                    }

                    initialized = true;
                }
                catch (Exception ex)
                {
                    LogManager.Log(ex, "Application Initialization Error!");
                    ApplicationInitializationError?.Invoke(this, ex);
                    return;
                }
            });


            if (initialized)
            {
                try
                {
                    if (settings.ApplicationState == ApplicationStates.PreSetup || settings.ApplicationState == ApplicationStates.FactoryRestore)
                    {
                        LogManager.Log($"The application is in {settings.ApplicationState} state. database initialization skipped. Invoking setup required event!");
                        SetupRequired?.Invoke(this, new EventArgs());
                    }
                    else
                    {
                        PostDbInitialize();
                    }
                }
                catch (Exception ex)
                {
                    LogManager.Log(ex, "Application Post Initialization Error!");
                    ApplicationInitializationError?.Invoke(this, ex);
                    return;
                }
            }
        }

        /// <summary>
        /// Called when the database has been initialized
        /// </summary>
        private void PostDbInitialize()
        {
            LogManager.Log($"Raising {nameof(ApplicationStarted)} event...");

            ApplicationStarted?.Invoke(this, new EventArgs());

            LogManager.Log("Invoking PPC view models OnApplicationStarted methods...");
            foreach (var vm in TangoIOC.Default.GetAllInstancesByBase<PPCViewModel>())
            {
                if (!_notifiedViewModels.Contains(vm))
                {
                    LogManager.Log($"Invoking {vm.GetType().Name}.OnApplicationStarted...");
                    vm.OnApplicationStarted();
                    _notifiedViewModels.Add(vm);
                }
            }

            var internalModules = this.GetType().Assembly.GetTypes().Where(xx => typeof(PPCModuleBase).IsAssignableFrom(xx)).ToList();

            LogManager.Log("Waiting for IPPCModuleLoader instance injection...");
            TangoIOC.Default.GetInstanceWhenAvailable<IPPCModuleLoader>((loader) =>
            {
                LogManager.Log("Module loader instance has been registered. Registering for the ModulesLoaded event...");

                ILayoutView layoutView = TangoIOC.Default.GetInstance<ILayoutView>();

                loader.ModulesLoaded += (x, y) =>
                {
                    LogManager.Log("Loading modules views");
                    _dispatcher.InvokeBlock(() =>
                    {
                        foreach (var module in TangoIOC.Default.GetInstance<IPPCModuleLoader>().UserModules)
                        {
                            if (!layoutView.GetNavigationControl().Elements.ToList().Exists(m => m.GetType() == module.MainViewType))
                            {
                                try
                                {
                                    LogManager.Log("Loading module view " + module.Name + "...");
                                    FrameworkElement view = Activator.CreateInstance(module.MainViewType) as FrameworkElement;
                                    SharedUI.Controls.NavigationControl.SetNavigationName(view, module.Name);
                                    layoutView.GetNavigationControl().Elements.Add(view);
                                }
                                catch (Exception ex)
                                {
                                    LogManager.Log(ex, $"Error loading module view for module {module.Name}.");
                                }
                            }
                        }

                        //Adding internal modules.
                        LogManager.Log("Loading internal modules...");
                        foreach (var type in internalModules)
                        {
                            var module = Activator.CreateInstance(type) as IPPCModule;
                            LogManager.Log("Loading module view " + module.Name + "...");
                            FrameworkElement view = Activator.CreateInstance(module.MainViewType) as FrameworkElement;
                            SharedUI.Controls.NavigationControl.SetNavigationName(view, module.Name);
                            layoutView.GetNavigationControl().Elements.Add(view);
                            _moduleLoader.AllModules.Add(module);
                            _moduleLoader.UserModules.Add(module);
                        }
                    });

                    LogManager.Log($"{loader.UserModules.Count} modules loaded.");

                    LogManager.Log($"Invoking {nameof(ModulesInitialized)} event.");
                    ModulesInitialized?.Invoke(this, new EventArgs());

                    FinalizeModuleInitialization();
                };
            });
        }

        /// <summary>
        /// Finalizes the module initialization.
        /// </summary>
        private void FinalizeModuleInitialization()
        {
            var settings = SettingsManager.Default.GetOrCreate<PPCSettings>();

            LogManager.Log("Finalizing application initialization...");

            LogManager.Log("Initializing Machine Provider...");
            _machineProvider.Init(_machine, _machineContext);

            LogManager.Log("Starting Machine Data Synchronizer...");
            _machineDataSynchronizer.IsEnabled = true;

            LogManager.Log("Applications initialization completed!");

            LogManager.Log("Checking for un-notified PPC view models...");
            foreach (var vm in TangoIOC.Default.GetAllInstancesByBase<PPCViewModel>())
            {
                if (!_notifiedViewModels.Contains(vm))
                {
                    LogManager.Log($"Invoking {vm.GetType().Name}.OnApplicationStarted...");
                    vm.OnApplicationStarted();
                    _notifiedViewModels.Add(vm);
                }
            }

            _dispatcher.Invoke(() =>
            {
                LogManager.Log($"Invoking {nameof(ApplicationReady)} event.");
                _eventLogger.Log(EventTypes.APPLICATION_STARTED, "Application Started!");
                ApplicationReady?.Invoke(this, new EventArgs());

                LogManager.Log("Notifying view models about application ready...");
                foreach (var vm in TangoIOC.Default.GetAllInstancesByBase<PPCViewModel>())
                {
                    LogManager.Log($"Invoking {vm.GetType().Name}.OnApplicationReady...");
                    vm.OnApplicationReady();
                }

                if (settings.EnableTechnicianModeByDefault)
                {
                    EnterTechnicianMode(false);
                }

                if (settings.EnableLockScreen)
                {
                    _screenLockTimer = new ActionTimer(settings.LockScreenTimeout);
                    _screenLockTimer.ResetReplace(ScreenLockTimerAction);
                }

                TangoMessenger.Default.Register<MachineSettingsSavedMessage>((msg) =>
                {
                    if (_screenLockTimer != null)
                    {
                        _screenLockTimer.Dispose();
                        _screenLockTimer = null;
                    }

                    if (settings.EnableLockScreen)
                    {
                        _screenLockTimer = new ActionTimer(settings.LockScreenTimeout);
                        _screenLockTimer.ResetReplace(ScreenLockTimerAction);
                    }
                });
            });
        }

        /// <summary>
        /// Shutdown the application.
        /// </summary>
        public async void ShutDown()
        {
            if (IsShuttingDown) return;

            IsShuttingDown = true;

            try
            {
                LogManager.Log("Shutting down application...");
                _watchdogServer.Dispose();

                foreach (var vm in TangoIOC.Default.GetAllInstancesByBase<PPCViewModel>())
                {
                    vm.OnApplicationShuttingDown();
                }
            }
            catch { }

            try
            {
                await FinalizeApplication();
            }
            catch (Exception ex)
            {
                LogManager.Log(ex, "Error occurred on application shutdown finalization.");
            }

            Environment.Exit(0);
        }

        /// <summary>
        /// Restarts the application.
        /// </summary>
        public async void Restart()
        {
            if (IsShuttingDown) return;

            IsShuttingDown = true;

            try
            {
                _dispatcher.Invoke(() =>
                {
                    var nav = TangoIOC.Default.GetInstance<INavigationManager>();
                    if (nav != null)
                    {
                        nav.NavigateTo(NavigationView.RestartingView);
                    }
                });

                LogManager.Log("Restarting the application...");

                await Task.Delay(8000);

                _watchdogServer.Dispose();

                foreach (var vm in TangoIOC.Default.GetAllInstancesByBase<PPCViewModel>())
                {
                    try
                    {
                        vm.OnApplicationShuttingDown();
                    }
                    catch { }
                }
            }
            catch { }

            try
            {
                if (_machineProvider.MachineOperator.State == Transport.TransportComponentState.Connected)
                {
                    _machineProvider.MachineOperator.Adapter.Disconnect().Wait();
                }
            }
            catch { }

            try
            {
                await FinalizeApplication();
            }
            catch (Exception ex)
            {
                LogManager.Log(ex, "Error occurred on application shutdown finalization.");
            }

            Process.Start(Application.ResourceAssembly.Location);
            Environment.Exit(0);
        }

        /// <summary>
        /// Runs the updater utility and exits the application.
        /// </summary>
        public async void UpdateApplication(String updaterPath, String arguments)
        {
            if (IsShuttingDown) return;

            IsShuttingDown = true;

            LogManager.Log("Restarting application for update...");

            try
            {
                LogManager.Log("Navigating to restart view...");
                _dispatcher.Invoke(() =>
                {
                    var nav = TangoIOC.Default.GetInstance<INavigationManager>();
                    if (nav != null)
                    {
                        nav.NavigateTo(NavigationView.RestartingView);
                    }
                });

                LogManager.Log("Waiting 2 seconds...");
                await Task.Delay(2000);

                try
                {
                    LogManager.Log("Disposing watch dog...");
                    _watchdogServer.Dispose();
                }
                catch (Exception ex)
                {
                    LogManager.Log(ex, "Error disposing watch dog.");
                }

                LogManager.Log("Raising OnApplicationShutDown for all view models...");
                foreach (var vm in TangoIOC.Default.GetAllInstancesByBase<PPCViewModel>())
                {
                    try
                    {
                        vm.OnApplicationShuttingDown();
                    }
                    catch (Exception ex)
                    {
                        LogManager.Log(ex, $"Error on {vm.GetType().Name}.OnApplicationShutDown().");
                    }
                }
            }
            catch { }

            try
            {
                LogManager.Log("Saving application settings...");
                SettingsManager.Default.GetOrCreate<PPCSettings>().PreviousApplicationVersion = Version.ToString();
                SettingsManager.Default.Save();
            }
            catch (Exception ex)
            {
                LogManager.Log(ex, "Error saving application settings.");
            }

            try
            {
                await FinalizeApplication();
            }
            catch (Exception ex)
            {
                LogManager.Log(ex, "Error occurred on application shutdown finalization.");
            }

            LogManager.Log($"Executing '{updaterPath}' with arguments '{arguments}'...");

            Process p = new Process();
            p.StartInfo.FileName = updaterPath;
            p.StartInfo.Arguments = arguments;
            p.StartInfo.LoadUserProfile = true;
            p.StartInfo.UseShellExecute = true;
            p.Start();

            LogManager.Log("Terminating application...");
            Environment.Exit(0);
        }

        /// <summary>
        /// Enteres the application technician mode.
        /// </summary>
        public async void EnterTechnicianMode(bool displayNotification = true)
        {
            if (displayNotification)
            {
                var vm = await _notificationProvider.ShowDialog<TechnicianModeLoginViewVM>();

                if (vm.DialogResult)
                {
                    if (vm.Password == "Aa123456")
                    {
                        IsInTechnicianMode = true;
                        _moduleLoader.AllModules.ToList().ForEach(x => x.OnTechnicianEntered());
                        await _notificationProvider.ShowInfo("Technician mode is now enabled.");
                    }
                    else
                    {
                        await _notificationProvider.ShowError("Invalid technician mode password.");
                        EnterTechnicianMode();
                    }
                }
            }
            else
            {
                IsInTechnicianMode = true;
                _moduleLoader.AllModules.ToList().ForEach(x => x.OnTechnicianEntered());
            }
        }

        /// <summary>
        /// Exits the application technician mode.
        /// </summary>
        public void ExitTechnicianMode()
        {
            IsInTechnicianMode = false;
            _moduleLoader.AllModules.ToList().ForEach(x => x.OnTechnicianExited());
            _notificationProvider.ShowInfo("Technician mode is now disabled.");
        }

        /// <summary>
        /// Invokes a dialog for entering a password and releasing the screen lock.
        /// </summary>
        public async void ReleaseScreenLock()
        {
            if (IsScreenLocked)
            {
                var vm = await _notificationProvider.ShowDialog<ScreenLockViewVM>();

                if (vm.DialogResult)
                {
                    if (vm.Password == SettingsManager.Default.GetOrCreate<PPCSettings>().LockScreenPassword)
                    {
                        IsScreenLocked = false;
                        ResetScreenLockTimer();
                    }
                }
            }
        }

        public void ResetScreenLockTimer()
        {
            if (_screenLockTimer != null)
            {
                _screenLockTimer.ResetReplace(ScreenLockTimerAction);
            }
        }

        private void ScreenLockTimerAction()
        {
            IsScreenLocked = true;
        }

        public void SetWindowState(WindowState state)
        {
            InvokeUI(() =>
            {
                MainWindow.Instance.WindowState = state;
            });
        }

        private Task FinalizeApplication()
        {
            LogManager.Log("Finalizing application...");

            return LimitedTimeTask.StartNew(() =>
            {
                try
                {
                    LogManager.Log("Flushing machine events...");
                    _eventLogger.Log(EventTypes.APPLICATION_TERMINATED, "User Interface Terminated.");
                    _eventLogger.FlushAll();
                }
                catch (Exception ex)
                {
                    LogManager.Log(ex, "Error flushing machine events.");
                }

                try
                {
                    LogManager.Log("Disposing insights manager (max 40 seconds to complete)...");
                    Stopwatch watch = new Stopwatch();
                    watch.Start();
                    var frame = InsightsFrame.CreateEmpty(DateTime.UtcNow);
                    InsightsManager.Default.InsertFrame(frame);
                    InsightsManager.Default.Dispose();
                    watch.Stop();
                    LogManager.Log($"Insights manager disposed after {(int)watch.Elapsed.TotalSeconds} seconds.");
                }
                catch (Exception ex)
                {
                    LogManager.Log(ex, "Error disposing insights manager.");
                }
            }, TimeSpan.FromSeconds(40));
        }
    }
}