using DynamicData.Binding;
using ReactiveUI;
using ReactiveUI.Fody.Helpers;
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Reactive.Disposables;
using System.Reactive.Linq;
using System.Reflection;
using System.Threading;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Input;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;
using Orc.FileAssociation;
using Wabbajack.Common;
using Wabbajack.DTOs.Interventions;
using Wabbajack.Interventions;
using Wabbajack.Messages;
using Wabbajack.Models;
using Wabbajack.Networking.WabbajackClientApi;
using Wabbajack.Paths;
using Wabbajack.Paths.IO;
using Wabbajack.UserIntervention;
using Wabbajack.View_Models;

namespace Wabbajack
{
    /// <summary>
    /// Main View Model for the application.
    /// Keeps track of which sub view is being shown in the window, and has some singleton wiring like WorkQueue and Logging.
    /// </summary>
    public class MainWindowVM : ViewModel
    {
        public MainWindow MainWindow { get; }

        [Reactive]
        public ViewModel ActivePane { get; private set; }

        public ObservableCollectionExtended<IStatusMessage> Log { get; } = new ObservableCollectionExtended<IStatusMessage>();

        public readonly CompilerVM Compiler;
        public readonly InstallerVM Installer;
        public readonly SettingsVM SettingsPane;
        public readonly ModListGalleryVM Gallery;
        public readonly ModeSelectionVM ModeSelectionVM;
        public readonly WebBrowserVM WebBrowserVM;
        public readonly Lazy<ModListContentsVM> ModListContentsVM;
        public readonly UserInterventionHandlers UserInterventionHandlers;
        private readonly Client _wjClient;
        private readonly ILogger<MainWindowVM> _logger;
        private readonly ResourceMonitor _resourceMonitor;

        private List<ViewModel> PreviousPanes = new();
        private readonly IServiceProvider _serviceProvider;

        public ICommand CopyVersionCommand { get; }
        public ICommand ShowLoginManagerVM { get; }
        public ICommand OpenSettingsCommand { get; }

        public string VersionDisplay { get; }

        [Reactive]
        public string ResourceStatus { get; set; }

        [Reactive]
        public string AppName { get; set; }

        [Reactive]
        public bool UpdateAvailable { get; private set; }

        public MainWindowVM(ILogger<MainWindowVM> logger, Client wjClient,
            IServiceProvider serviceProvider, ModeSelectionVM modeSelectionVM, ModListGalleryVM modListGalleryVM, ResourceMonitor resourceMonitor,
            InstallerVM installer, CompilerVM compilerVM, SettingsVM settingsVM, WebBrowserVM webBrowserVM)
        {
            _logger = logger;
            _wjClient = wjClient;
            _resourceMonitor = resourceMonitor;
            _serviceProvider = serviceProvider;
            ConverterRegistration.Register();
            Installer = installer;
            Compiler = compilerVM;
            SettingsPane = settingsVM;
            Gallery = modListGalleryVM;
            ModeSelectionVM = modeSelectionVM;
            WebBrowserVM = webBrowserVM;
            ModListContentsVM = new Lazy<ModListContentsVM>(() => new ModListContentsVM(serviceProvider.GetRequiredService<ILogger<ModListContentsVM>>(), this));
            UserInterventionHandlers = new UserInterventionHandlers(serviceProvider.GetRequiredService<ILogger<UserInterventionHandlers>>(), this);

            MessageBus.Current.Listen<NavigateToGlobal>()
                .Subscribe(m => HandleNavigateTo(m.Screen))
                .DisposeWith(CompositeDisposable);

            MessageBus.Current.Listen<NavigateTo>()
                .Subscribe(m => HandleNavigateTo(m.ViewModel))
                .DisposeWith(CompositeDisposable);

            MessageBus.Current.Listen<NavigateBack>()
                .Subscribe(HandleNavigateBack)
                .DisposeWith(CompositeDisposable);

            MessageBus.Current.Listen<SpawnBrowserWindow>()
                .ObserveOnGuiThread()
                .Subscribe(HandleSpawnBrowserWindow)
                .DisposeWith(CompositeDisposable);

            _resourceMonitor.Updates
                .Select(r => string.Join(", ", r.Where(r => r.Throughput > 0)
                    .Select(s => $"{s.Name} - {s.Throughput.ToFileSizeString()}/sec")))
                .BindToStrict(this, view => view.ResourceStatus);


            if (IsStartingFromModlist(out var path))
            {
                LoadModlistForInstalling.Send(path, null);
                NavigateToGlobal.Send(NavigateToGlobal.ScreenType.Installer);
            }
            else
            {
                // Start on mode selection
                NavigateToGlobal.Send(NavigateToGlobal.ScreenType.ModeSelectionView);
            }

            try
            {
                var assembly = Assembly.GetExecutingAssembly();
                var assemblyLocation = assembly.Location;
                var processLocation = Process.GetCurrentProcess().MainModule?.FileName ?? throw new Exception("Process location is unavailable!");

                _logger.LogInformation("Assembly Location: {AssemblyLocation}", assemblyLocation);
                _logger.LogInformation("Process Location: {ProcessLocation}", processLocation);

                var fvi = FileVersionInfo.GetVersionInfo(string.IsNullOrWhiteSpace(assemblyLocation) ? processLocation : assemblyLocation);
                Consts.CurrentMinimumWabbajackVersion = Version.Parse(fvi.FileVersion);
                VersionDisplay = $"v{fvi.FileVersion}";
                AppName = "WABBAJACK " + VersionDisplay;
                _logger.LogInformation("Wabbajack Version: {FileVersion}", fvi.FileVersion);

                Task.Run(() => _wjClient.SendMetric("started_wabbajack", fvi.FileVersion)).FireAndForget();
                Task.Run(() => _wjClient.SendMetric("started_sha", ThisAssembly.Git.Sha));

                // setup file association
                try
                {
                    var applicationRegistrationService = _serviceProvider.GetRequiredService<IApplicationRegistrationService>();

                    var applicationInfo = new ApplicationInfo("Wabbajack", "Wabbajack", "Wabbajack", processLocation);
                    applicationInfo.SupportedExtensions.Add("wabbajack");
                    applicationRegistrationService.RegisterApplication(applicationInfo);
                }
                catch (Exception ex)
                {
                    _logger.LogError(ex, "While setting up file associations");
                }
            }
            catch (Exception ex)
            {
                _logger.LogError(ex, "During App configuration");
                VersionDisplay = "ERROR";
            }
            CopyVersionCommand = ReactiveCommand.Create(() =>
            {
                Clipboard.SetText($"Wabbajack {VersionDisplay}\n{ThisAssembly.Git.Sha}");
            });
            OpenSettingsCommand = ReactiveCommand.Create(
                canExecute: this.WhenAny(x => x.ActivePane)
                    .Select(active => !object.ReferenceEquals(active, SettingsPane)),
                execute: () => NavigateToGlobal.Send(NavigateToGlobal.ScreenType.Settings));
        }

        private void HandleNavigateTo(ViewModel objViewModel)
        {

            ActivePane = objViewModel;
        }

        private void HandleNavigateBack(NavigateBack navigateBack)
        {
            ActivePane = PreviousPanes.Last();
            PreviousPanes.RemoveAt(PreviousPanes.Count - 1);
        }

        private void HandleManualDownload(ManualDownload manualDownload)
        {
            var handler = _serviceProvider.GetRequiredService<ManualDownloadHandler>();
            handler.Intervention = manualDownload;
            //MessageBus.Current.SendMessage(new OpenBrowserTab(handler));
        }

        private void HandleManualBlobDownload(ManualBlobDownload manualDownload)
        {
            var handler = _serviceProvider.GetRequiredService<ManualBlobDownloadHandler>();
            handler.Intervention = manualDownload;
            //MessageBus.Current.SendMessage(new OpenBrowserTab(handler));
        }

        private void HandleSpawnBrowserWindow(SpawnBrowserWindow msg)
        {
            var window = _serviceProvider.GetRequiredService<BrowserWindow>();
            window.DataContext = msg.Vm;
            window.Show();
        }

        private void HandleNavigateTo(NavigateToGlobal.ScreenType s)
        {
            if (s is NavigateToGlobal.ScreenType.Settings)
                PreviousPanes.Add(ActivePane);

            ActivePane = s switch
            {
                NavigateToGlobal.ScreenType.ModeSelectionView => ModeSelectionVM,
                NavigateToGlobal.ScreenType.ModListGallery => Gallery,
                NavigateToGlobal.ScreenType.Installer => Installer,
                NavigateToGlobal.ScreenType.Compiler => Compiler,
                NavigateToGlobal.ScreenType.Settings => SettingsPane,
                _ => ActivePane
            };
        }


        private static bool IsStartingFromModlist(out AbsolutePath modlistPath)
        {
            var args = Environment.GetCommandLineArgs();
            if (args.Length == 2)
            {
                var arg = args[1].ToAbsolutePath();
                if (arg.FileExists() && arg.Extension == Ext.Wabbajack)
                {
                    modlistPath = arg;
                    return true;
                }
            }

            modlistPath = default;
            return false;
        }

        public void CancelRunningTasks(TimeSpan timeout)
        {
            var endTime = DateTime.Now.Add(timeout);
            var cancellationTokenSource = _serviceProvider.GetRequiredService<CancellationTokenSource>();
            cancellationTokenSource.Cancel();

            bool IsInstalling() => Installer.InstallState is InstallState.Installing;

            while (DateTime.Now < endTime && IsInstalling())
            {
                Thread.Sleep(TimeSpan.FromSeconds(1));
            }
        }

        /*
        public void NavigateTo(ViewModel vm)
        {
            ActivePane = vm;
        }*/

        /*
        public void NavigateTo<T>(T vm)
            where T : ViewModel, IBackNavigatingVM
        {
            vm.NavigateBackTarget = ActivePane;
            ActivePane = vm;
        }*/

        public async Task ShutdownApplication()
        {
            /*
            Dispose();
            Settings.PosX = MainWindow.Left;
            Settings.PosY = MainWindow.Top;
            Settings.Width = MainWindow.Width;
            Settings.Height = MainWindow.Height;
            await MainSettings.SaveSettings(Settings);
            Application.Current.Shutdown();
            */
        }
    }
}