using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Tango.BL.Entities;
using Tango.Core.Commands;
using Tango.Core.IO;
using Tango.FSE.BL;
using Tango.FSE.Common;
using Tango.FSE.Common.Navigation;
using Tango.FSE.Common.RemoteUpgrade;
using Tango.FSE.Upgrade.Views;
using static Tango.FSE.Upgrade.ViewModels.ApplicationUpgradeGeneratedViewVM;

namespace Tango.FSE.Upgrade.ViewModels
{
    public class ApplicationUpgradeGeneratedViewVM : RemoteUpgradeViewModel, INavigationObjectReceiver<NavigationObject>
    {
        public class NavigationObject
        {
            public TangoVersion SelectedVersion { get; set; }
            public Machine SelectedMachine { get; set; }
            public bool UpgradeNow { get; set; }
            public TemporaryFile TemporaryTupFile { get; set; }
        }

        private String _tupFileLocation;
        public String TupFileLocation
        {
            get { return _tupFileLocation; }
            set { _tupFileLocation = value; RaisePropertyChangedAuto(); InvalidateRelayCommands(); }
        }

        private TemporaryFile _temporaryTupFile;
        public TemporaryFile TemporaryTupFile
        {
            get { return _temporaryTupFile; }
            set { _temporaryTupFile = value; InvalidateRelayCommands(); }
        }

        private bool _canUpgradeNow;
        public bool CanUpgradeNow
        {
            get { return _canUpgradeNow; }
            set { _canUpgradeNow = value; RaisePropertyChangedAuto(); InvalidateRelayCommands(); }
        }

        private String _canUpgradeNowError;
        public String CanUpgradeNowError
        {
            get { return _canUpgradeNowError; }
            set { _canUpgradeNowError = value; RaisePropertyChangedAuto(); }
        }

        private bool _isUpgradeNow;
        public bool IsUpgradeNow
        {
            get { return _isUpgradeNow; }
            set { _isUpgradeNow = value; RaisePropertyChangedAuto(); InvalidateRelayCommands(); }
        }

        private bool _isUpgradeNowSelected;
        public bool IsUpgradeNowSelected
        {
            get { return _isUpgradeNowSelected; }
            set { _isUpgradeNowSelected = value; RaisePropertyChangedAuto(); }
        }

        private TangoVersion _selectedVersion;
        public TangoVersion SelectedVersion
        {
            get { return _selectedVersion; }
            set { _selectedVersion = value; RaisePropertyChangedAuto(); InvalidateRelayCommands(); }
        }

        private Machine _selectedMachine;
        public Machine SelectedMachine
        {
            get { return _selectedMachine; }
            set { _selectedMachine = value; RaisePropertyChangedAuto(); }
        }

        private RemoteUpgradeHandler _handler;
        public RemoteUpgradeHandler Handler
        {
            get { return _handler; }
            set { _handler = value; RaisePropertyChangedAuto(); }
        }

        private bool _isCompleted;
        public bool IsCompleted
        {
            get { return _isCompleted; }
            set { _isCompleted = value; RaisePropertyChangedAuto(); InvalidateRelayCommands(); }
        }

        private bool _suppressFirmwareUpgrade;
        public bool SuppressFirmwareUpgrade
        {
            get { return _suppressFirmwareUpgrade; }
            set { _suppressFirmwareUpgrade = value; RaisePropertyChangedAuto(); }
        }


        public RelayCommand StartUpgradeCommand { get; set; }
        public RelayCommand SaveTupFileCommand { get; set; }
        public RelayCommand SelectTupFileLocationCommand { get; set; }

        public ApplicationUpgradeGeneratedViewVM()
        {
            Handler = new RemoteUpgradeHandler("Ready");
            StartUpgradeCommand = new RelayCommand(StartUpgrade, () => CanUpgradeNow && Handler.Status != RemoteUpgradeHandlerStatus.Completed);
            SaveTupFileCommand = new RelayCommand(SaveTupFile, () => TupFileLocation != null);
            SelectTupFileLocationCommand = new RelayCommand(SelectTupFileLocation, () => SelectedVersion != null && SelectedMachine != null);
        }

        public override void OnApplicationStarted()
        {
            base.OnApplicationStarted();
            MachineProvider.MachineConnected += (_, __) => InvalidateCanUpgradeNow();
            MachineProvider.MachineDisconnected += (_, __) => InvalidateCanUpgradeNow();
        }

        private async void SelectTupFileLocation()
        {
            String fileName = $"{SelectedMachine.SerialNumber}_Update_{DateTime.Now.Date.ToFileName()}_v{SelectedVersion.Version}.tup";
            var result = await StorageProvider.SaveFile("Select update package location", "Tango Update Package|*.tup", fileName, ".tup");
            if (result)
            {
                TupFileLocation = result.SelectedItem;
            }
        }

        private void InvalidateCanUpgradeNow()
        {
            CanUpgradeNowError = null;

            //if (!IsUpgradeNowSelected) return;

            if (SelectedMachine == null)
            {
                CanUpgradeNow = false;
                IsUpgradeNowSelected = false;
                CanUpgradeNowError = "Target machine not specified.";
                return;
            }

            if (!MachineProvider.IsConnected)
            {
                CanUpgradeNow = false;
                IsUpgradeNowSelected = false;
                CanUpgradeNowError = "The selected machine is not currently connected.";
                return;
            }

            if (MachineProvider.Machine.Guid != SelectedMachine.Guid)
            {
                CanUpgradeNow = false;
                IsUpgradeNowSelected = false;
                CanUpgradeNowError = "The selected machine is different from the one currently connected.";
                return;
            }

            if (!MachineProvider.ConnectionType.IsRemote())
            {
                CanUpgradeNow = false;
                IsUpgradeNowSelected = false;
                CanUpgradeNowError = "The current machine connection type does not support remote upgrade.";
                return;
            }

            CanUpgradeNow = true;
        }

        private async void StartUpgrade()
        {
            try
            {
                IsFree = false;
                Handler = await RemoteUpgradeManager.PerformRemoteApplicationUpgrade(TemporaryTupFile, !SuppressFirmwareUpgrade);
                await Handler.WaitForCompletion();
                IsCompleted = true;
                await MachineProvider.DisconnectAndWaitForReconnection(TimeSpan.FromSeconds(20), TimeSpan.FromMinutes(1), "The remote machine is now performing final upgrade operations.");
            }
            catch (OperationCanceledException)
            {
                //Aborted...
            }
            catch (AuthorizationException ex)
            {
                await NotificationProvider.ShowError(ex.Message);
            }
            catch (Exception ex)
            {
                LogManager.Log(ex, "Error occurred while executing remote application upgrade.");
            }
            finally
            {
                await TemporaryTupFile.DeleteAsync();
                IsFree = true;
                InvalidateRelayCommands();
            }
        }

        private async void SaveTupFile()
        {
            try
            {
                File.Copy(TemporaryTupFile, TupFileLocation, true);
                TemporaryTupFile.Delete();
                IsCompleted = true;
                await NotificationProvider.ShowSuccess("Application upgrade package saved successfully.");
                await ModularNavigationManager.NavigateBack();
            }
            catch (Exception ex)
            {
                LogManager.Log(ex, "Error copying temporary tup file to selected location.");
                await NotificationProvider.ShowError($"Error occurred while trying to save the application package file.\n{ex.FlattenMessage()}");
            }
        }

        public void OnNavigatedToWithObject(NavigationObject obj)
        {
            SelectedVersion = obj.SelectedVersion;
            SelectedMachine = obj.SelectedMachine;
            IsUpgradeNow = obj.UpgradeNow;
            IsUpgradeNowSelected = IsUpgradeNow;
            TemporaryTupFile = obj.TemporaryTupFile;
            InvalidateCanUpgradeNow();
            InvalidateRelayCommands();
        }

        public override void OnBeforeNavigatedTo()
        {
            base.OnBeforeNavigatedTo();
            Handler = new RemoteUpgradeHandler("Ready");
            IsCompleted = false;
            SelectedVersion = null;
            SelectedMachine = null;
            IsUpgradeNow = false;
            IsUpgradeNowSelected = false;
            TemporaryTupFile = null;
            InvalidateRelayCommands();
        }

        public async override Task<bool> OnNavigateBackRequest()
        {
            if (!IsCompleted)
            {
                var abort = await NotificationProvider.ShowWarningQuestion("Are you sure you want to abort the upgrade operation?");

                if (Handler.Status == RemoteUpgradeHandlerStatus.Started)
                {
                    if (Handler.CanAbort)
                    {
                        Handler.Abort();
                    }
                    else
                    {
                        await NotificationProvider.ShowWarning("Cannot abort the operation at this stage.");
                        return false;
                    }
                }

                return abort;
            }

            return true;
        }
    }
}