using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Tango.Core.Commands;
using Tango.Core.Helpers;
using Tango.Explorer;
using Tango.PPC.Common;
using Tango.PPC.Common.MachineUpdate;
using Tango.PPC.Common.Publish;
using Tango.PPC.Common.Web;
using Tango.PPC.UI.Dialogs;
using Tango.PPC.UI.Notifications.NotificationItems;
using Tango.PPC.UI.ViewsContracts;

namespace Tango.PPC.UI.ViewModels
{
    public class MachineUpdateViewVM : PPCViewModel<IMachineUpdateView>
    {
        public enum MachineUpdateView
        {
            UpdateCheckView,
            UpdateCheckErrorView,
            UpdateAvailableView,
            UpToDateView,
            UpdateProgressView,
            UpdateDbProgressView,
            UpdateCompletedView,
            UpdateFailedView,
            UpdateFromPackageView,
            UpdateFailedFromPackageView,
        }

        private MachineUpdateResult _update_result;
        private DbCompareResult _db_compare_result;
        private bool _isChecking;
        private CheckForUpdateResponse _checkUpdateResponse;
        private UpdateAvailableNotificationItem _updateNotificationItem;

        #region Properties

        /// <summary>
        /// Gets or sets the machine update manager.
        /// </summary>
        public IMachineUpdateManager MachineUpdateManager { get; set; }

        private String _latestVersion;
        /// <summary>
        /// Gets or sets the latest version.
        /// </summary>
        public String LatestVersion
        {
            get { return _latestVersion; }
            set { _latestVersion = value; RaisePropertyChangedAuto(); }
        }

        private bool _isDbUpdate;
        /// <summary>
        /// Gets or sets a value indicating whether this instance is database update.
        /// </summary>
        public bool IsDbUpdate
        {
            get { return _isDbUpdate; }
            set { _isDbUpdate = value; RaisePropertyChangedAuto(); }
        }

        private String _failedError;
        /// <summary>
        /// Gets or sets the setup failed error.
        /// </summary>
        public String FailedError
        {
            get { return _failedError; }
            set { _failedError = value; RaisePropertyChangedAuto(); }
        }

        #endregion

        #region Commands

        /// <summary>
        /// Gets or sets the complete command.
        /// </summary>
        public RelayCommand CompleteCommand { get; set; }

        /// <summary>
        /// Gets or sets the install command.
        /// </summary>
        public RelayCommand UpdateCommand { get; set; }

        /// <summary>
        /// Gets or sets the restart command.
        /// </summary>
        public RelayCommand RestartCommand { get; set; }

        /// <summary>
        /// Gets or sets the close command.
        /// </summary>
        public RelayCommand CloseCommand { get; set; }

        /// <summary>
        /// Gets or sets to application command.
        /// </summary>
        public RelayCommand ToApplicationCommand { get; set; }

        #endregion

        #region Constructors

        public MachineUpdateViewVM(IMachineUpdateManager machineUpdateManager)
        {
            MachineUpdateManager = machineUpdateManager;

            CompleteCommand = new RelayCommand(CompleteUpdate);
            UpdateCommand = new RelayCommand(Update);
            RestartCommand = new RelayCommand(CheckForUpdates);
            CloseCommand = new RelayCommand(() =>
            {
                NavigationManager.NavigateTo(Common.Navigation.NavigationView.HomeModule);
                NavigateTo(MachineUpdateView.UpdateCheckView);
            });

            ToApplicationCommand = new RelayCommand(() =>
            {
                NavigationManager.NavigateTo(Common.Navigation.NavigationView.HomeModule);
                NavigateTo(MachineUpdateView.UpdateCheckView);
            });

            machineUpdateManager.UpdateAvailable += MachineUpdateManager_UpdateAvailable;
        }

        #endregion

        #region Update

        public async void CheckForUpdates()
        {
            await NavigateTo(MachineUpdateView.UpdateCheckView);

            if (_isChecking) return;

            try
            {
                _isChecking = true;
                IsDbUpdate = false;

                await Task.Delay(2000);
                if (!await ConnectivityProvider.CheckInternetConnection())
                {
                    _isChecking = false;
                    await NavigateTo(MachineUpdateView.UpdateCheckErrorView);
                    return;
                }

                var response = await MachineUpdateManager.CheckForUpdate(MachineProvider.Machine.SerialNumber);
                _checkUpdateResponse = response;

                if (response.IsUpdateAvailable)
                {
                    LatestVersion = response.Version;
                    await NavigateTo(MachineUpdateView.UpdateAvailableView);
                }
                else if (response.IsDatabaseUpdateAvailable)
                {
                    IsDbUpdate = true;
                    _db_compare_result = new DbCompareResult()
                    {
                        RequiresUpdate = true,
                        UpdateDBResponse = response.UpdateDBResponse
                    };
                    await NavigateTo(MachineUpdateView.UpdateAvailableView);
                }
                else
                {
                    _db_compare_result = await MachineUpdateManager.UpdateDBCheck(MachineProvider.Machine.SerialNumber);

                    if (_db_compare_result.RequiresUpdate)
                    {
                        IsDbUpdate = true;
                        await NavigateTo(MachineUpdateView.UpdateAvailableView);
                    }
                    else
                    {
                        await NavigateTo(MachineUpdateView.UpToDateView);
                    }
                }
            }
            catch (Exception ex)
            {
                FailedError = ex.FlattenMessage();
                LogManager.Log(ex, "Error while trying to check for updates.");
                await NavigateTo(MachineUpdateView.UpdateFailedView);
            }
            finally
            {
                _isChecking = false;
            }
        }

        private async void Update()
        {
            if (!IsDbUpdate)
            {
                await NavigateTo(MachineUpdateView.UpdateProgressView);

                LogManager.Log("Starting machine update...");

                try
                {
                    _update_result = await MachineUpdateManager.Update(_checkUpdateResponse.SetupFirmware, _checkUpdateResponse.SetupFPGA);
                    LogManager.Log("Machine update completed.");
                    await NavigateTo(MachineUpdateView.UpdateCompletedView);
                }
                catch (Exception ex)
                {
                    FailedError = ex.FlattenMessage();
                    LogManager.Log(ex, "Machine update failed.");
                    await NavigateTo(MachineUpdateView.UpdateFailedView);
                }
            }
            else
            {
                await NavigateTo(MachineUpdateView.UpdateDbProgressView);
                LogManager.Log("Starting database update...");

                try
                {
                    await MachineUpdateManager.UpdateDB(_db_compare_result, MachineProvider.Machine.SerialNumber);
                    LogManager.Log("Database update completed.");
                    await NavigateTo(MachineUpdateView.UpdateCompletedView);
                }
                catch (Exception ex)
                {
                    FailedError = ex.FlattenMessage();
                    LogManager.Log(ex, "Database update failed.");
                    await NavigateTo(MachineUpdateView.UpdateFailedView);
                }
            }
        }

        #endregion

        #region Complete

        private void CompleteUpdate()
        {
            LogManager.Log("Completing machine update...");

            if (IsDbUpdate || !_update_result.RequiresBinariesUpdate)
            {
                LogManager.Log("Restarting Application...");
                ApplicationManager.Restart();
            }
            else
            {
                String updater_exe = Path.Combine(_update_result.UpdatePackagePath, "Tango.PPC.Updater.exe");
                ApplicationManager.UpdateApplication(updater_exe, PathHelper.GetStartupPath());
            }
        }

        #endregion

        #region Override Methods

        /// <summary>
        /// Called when the application has been started.
        /// </summary>
        public override void OnApplicationStarted()
        {

        }

        /// <summary>
        /// Navigates to the specified view.
        /// </summary>
        /// <param name="view">The view.</param>
        private Task NavigateTo(MachineUpdateView view)
        {
            return View.NavigateTo(view);
        }

        /// <summary>
        /// Called when the application is ready and all modules views are loaded.
        /// </summary>
        public override void OnApplicationReady()
        {
            base.OnApplicationReady();

            StorageProvider.RegisterFileHandler(ExplorerFileDefinition.Update.Extension, HandleSoftwareUpdatePackageLoaded);

            if (ApplicationManager.IsAfterUpdate)
            {
                RunPostUpdatePackages();
            }
            else
            {
                MachineUpdateManager.EnableAutoCheckForUpdates = true;
            }
        }

        /// <summary>
        /// Called when the navigation system has navigated to this VM view.
        /// </summary>
        public override void OnNavigatedTo()
        {
            base.OnNavigatedTo();

            if (_updateNotificationItem != null)
            {
                _updateNotificationItem.Close();
                _updateNotificationItem = null;
            }
        }

        #endregion

        #region Post Update Packages

        private async void RunPostUpdatePackages()
        {
            await Task.Delay(1000);

            LogManager.Log("Application was loaded after an update. Checking for required post-update packages...");

            bool required = false;

            try
            {
                required = await MachineUpdateManager.PostUpdatePackagesRequired();
            }
            catch (Exception ex)
            {
                LogManager.Log(ex, "Error checking for post-update packages.");
            }

            if (required)
            {
                LogManager.Log("Post-update packages found and needs to be installed. Navigating to machine update and running post-update packages...");
                await NavigationManager.NavigateTo(Common.Navigation.NavigationView.MachineUpdateView);
                await NavigateTo(MachineUpdateView.UpdateProgressView);
                try
                {
                    var result = await MachineUpdateManager.RunPostUpdatePackages();

                    LogManager.Log("Post-update packages installed successfully.");

                    await Task.Delay(2000);

                    if (result.RestartRequired)
                    {
                        LogManager.Log("Restart required. Restarting...");
                        ApplicationManager.Restart();
                    }
                    else
                    {
                        await NavigationManager.NavigateTo(Common.Navigation.NavigationView.LayoutView);
                    }
                }
                catch (Exception ex)
                {
                    LogManager.Log(ex, "Error occurred while running post-update packages.");
                }
            }
            else
            {
                LogManager.Log("No post-update packages installation required.");
            }
        }

        #endregion

        #region Handle USB Update

        private async void HandleSoftwareUpdatePackageLoaded(ExplorerFileItem fileItem)
        {
            PublishInfo packageFile = null;

            try
            {
                packageFile = await MachineUpdateManager.GetUpdatePackageFileInfo(fileItem.Path);
            }
            catch (Exception ex)
            {
                LogManager.Log(ex, $"Error loading publish info from {fileItem.Path}.");
                await NotificationProvider.ShowError("An error occurred while trying to load the selected software update package. Please make sure the package is valid.");
                return;
            }

            UpdateFromFileViewVM vm = new UpdateFromFileViewVM();
            vm.Version = packageFile.ApplicationVersion;

            await NotificationProvider.ShowDialog(vm);

            if (vm.DialogResult)
            {
                await NavigationManager.NavigateTo(Common.Navigation.NavigationView.MachineUpdateView);
                await NavigateTo(MachineUpdateView.UpdateProgressView);

                LogManager.Log("Starting machine update from package...");

                try
                {
                    _update_result = await MachineUpdateManager.UpdateFromTUP(fileItem.Path, MachineProvider.Machine.SetupFirmware, MachineProvider.Machine.SetupFpga);
                    LogManager.Log("Machine update from package completed.");
                    await NavigateTo(MachineUpdateView.UpdateCompletedView);
                }
                catch (Exception ex)
                {
                    LogManager.Log(ex, "Machine update from package failed.");
                    FailedError = ex.FlattenMessage();
                    await NavigateTo(MachineUpdateView.UpdateFailedFromPackageView);
                }
            }
        }

        #endregion

        #region Auto Check For Update

        private void MachineUpdateManager_UpdateAvailable(object sender, CheckForUpdateResponse e)
        {
            if (!IsVisible && _updateNotificationItem == null)
            {
                LogManager.Log($"New {(e.IsDatabaseUpdateAvailable ? "database updates" : "application version")} detected ({e.Version}). Pushing notification...");

                InvokeUI(() =>
                {
                    _updateNotificationItem = new UpdateAvailableNotificationItem();
                    _updateNotificationItem.Version = Version.Parse(e.Version).ToString(3);
                    _updateNotificationItem.IsDatabaseUpdate = e.IsDatabaseUpdateAvailable && !e.IsUpdateAvailable;
                    _updateNotificationItem.Pressed += (_, __) =>
                    {
                        _updateNotificationItem = null;

                        if (!IsVisible)
                        {
                            LogManager.Log("Update available notification pressed. Navigating to update view...");
                            NavigationManager.NavigateTo(Common.Navigation.NavigationView.MachineUpdateView);
                            CheckForUpdates();
                        }
                    };
                    _updateNotificationItem.Closed += (_, __) =>
                    {
                        _updateNotificationItem = null;
                    };
                    NotificationProvider.PushNotification(_updateNotificationItem);
                });
            }
        }

        #endregion
    }
}