using Avalonia;
using Avalonia.Controls.ApplicationLifetimes;
using Avalonia.Markup.Xaml;
using LehrerApp.Core.Services;
using LehrerApp.Data;
using LehrerApp.Desktop.Services;
using LehrerApp.Desktop.ViewModels;
using LehrerApp.Desktop.ViewModels.Groups;
using LehrerApp.Desktop.ViewModels.Planning;
using LehrerApp.Desktop.ViewModels.Students;
using LehrerApp.Desktop.Views;
using Microsoft.Extensions.DependencyInjection;

namespace LehrerApp.Desktop;

public class App : Application
{
    public static IServiceProvider Services { get; private set; } = null!;
    private static ServiceProvider? _serviceProvider;
    private static bool _exitHandlerAttached;

    public override void Initialize() => AvaloniaXamlLoader.Load(this);

    public override void OnFrameworkInitializationCompleted()
    {
        if (ApplicationLifetime is IClassicDesktopStyleApplicationLifetime desktop)
        {
            // Verschlüsselte Datenbank (13.3.4): Passwort abfragen, bevor die Datenbank
            // (und damit BuildServices, das sie öffnet) angefasst wird.
            if (AppBootstrapper.IsDbEncrypted())
            {
                var promptVm = new DbPasswordPromptViewModel(
                    new DatabaseEncryptionService(), AppBootstrapper.ResolveDbPath());
                var promptWindow = new DbPasswordPromptWindow { DataContext = promptVm };
                promptVm.OnUnlocked = password =>
                {
                    AppBootstrapper.DbPassword = password;
                    StartMainApp(desktop, showImmediately: true);
                    promptWindow.Close();
                };
                desktop.MainWindow = promptWindow;
            }
            else
            {
                StartMainApp(desktop, showImmediately: false);
            }
        }

        base.OnFrameworkInitializationCompleted();
    }

    private static void StartMainApp(
        IClassicDesktopStyleApplicationLifetime desktop, bool showImmediately)
    {
        _serviceProvider = AppBootstrapper.BuildServices();
        Services = _serviceProvider;
        Services.GetRequiredService<AppLogger>().Info("Anwendung gestartet.");
        GlobalExceptionHandler.AttachNotifications(Services.GetRequiredService<NotificationService>());

        if (!_exitHandlerAttached)
        {
            desktop.Exit += (_, _) => DisposeServices();
            _exitHandlerAttached = true;
        }

        var mainVm = Services.GetRequiredService<MainWindowViewModel>();
        WireCallbacks(mainVm);
        var main = new MainWindow { DataContext = mainVm };
        desktop.MainWindow = main;
        if (showImmediately) main.Show();
    }

    private static void DisposeServices()
    {
        if (_serviceProvider is null) return;

        try
        {
            _serviceProvider.GetService<LiteDbContext>()?.Checkpoint();
        }
        catch (Exception ex)
        {
            AppBootstrapper.Logger.Error("Datenbank-Checkpoint beim Beenden fehlgeschlagen.", ex);
        }
        finally
        {
            _serviceProvider.Dispose();
            _serviceProvider = null;
        }
    }

    private static void WireCallbacks(MainWindowViewModel main)
    {
        // GroupList → GroupDetail  (OnAddGroup wird in GroupListView.axaml.cs verdrahtet)
        var gl = Services.GetRequiredService<GroupListViewModel>();
        gl.OnNavigateToDetail = (id, tab) => main.NavigateToGroupDetail(id, tab);

        // Dashboard → GroupDetail (Chips) / StudentDetail (Fehlzeiten-/Förderplan-Hinweise)
        var dash = Services.GetRequiredService<DashboardViewModel>();
        dash.OnNavigateToGroup   = id => main.NavigateToGroupDetail(id);
        dash.OnNavigateToStudent = id => main.NavigateToStudent(id);

        // StudentList → StudentDetail + Anlegen
        var sl = Services.GetRequiredService<StudentListViewModel>();
        sl.OnNavigateToDetail = id => main.NavigateToStudent(id);
        sl.OnAddStudent       = () => ShowAddStudentDialog();

        // Stundenplan "Heute" → GroupDetail (Tab "Planung") / Einstellungen (Zahnrad, Tab "Ferien & Feiertage")
        var timetable = Services.GetRequiredService<TimetableViewModel>();
        timetable.OnNavigateToSettings = () => main.NavigateToSettings(7);
        timetable.OnNavigateToGroup = id => main.NavigateToGroupDetail(id, 5);
    }

    private static async Task ShowAddStudentDialog()
    {
        var vm = new ViewModels.Students.AddStudentDialogViewModel(
            Services.GetRequiredService<Core.Interfaces.IStudentRepository>());
        var dialog = new Views.Students.AddStudentDialog { DataContext = vm };
        if (Application.Current?.ApplicationLifetime is IClassicDesktopStyleApplicationLifetime { MainWindow: { } owner })
            await dialog.ShowDialog<bool>(owner);
    }
}