using System.ComponentModel;
using System.Windows;
using Explorer.App.Settings;
using Explorer.Hosting;
using Explorer.Presentation.ViewModels;

namespace Explorer.App;

public partial class SettingsWindow : Window
{
    private readonly MainViewModel _vm;
    private readonly SettingsDraft _draft;
    private readonly string _originalTheme;

    public SettingsDraft Draft => _draft;

    public SettingsWindow(MainViewModel vm)
    {
        _vm = vm;
        var prefs = vm.CurrentPreferences();
        _originalTheme = prefs.Theme;
        _draft = SettingsDraft.From(prefs);
        _draft.PropertyChanged += OnDraftChanged;
        var shell = new SettingsShell(_draft, SettingsCatalog.Create());
        DataContext = shell;
        InitializeComponent();
        shell.PropertyChanged += OnShellChanged;
        ShowSelectedPage();
        Closed += (_, _) =>
        {
            _draft.PropertyChanged -= OnDraftChanged;
            shell.PropertyChanged -= OnShellChanged;
        };
    }

    private void OnShellChanged(object? sender, PropertyChangedEventArgs e)
    {
        if (e.PropertyName is nameof(SettingsShell.SelectedCategory) or null)
        {
            ShowSelectedPage();
        }
    }

    private void ShowSelectedPage()
    {
        PageHost.Children.Clear();
        if (DataContext is not SettingsShell shell)
        {
            return;
        }

        var page = shell.SelectedCategory.Page;
        PageHost.Children.Add(page);
        page.DataContext = _draft;
    }

    private void OnDraftChanged(object? sender, PropertyChangedEventArgs e)
    {
        if (e.PropertyName is nameof(SettingsDraft.Theme)
            or nameof(SettingsDraft.IsDarkTheme)
            or nameof(SettingsDraft.IsLightTheme))
        {
            _vm.Theme = _draft.Theme;
        }
    }

    private async void OnOk(object sender, RoutedEventArgs e)
    {
        var prefs = _draft.ApplyTo(_vm.CurrentPreferences());
        await _vm.ApplyPreferencesAsync(prefs).ConfigureAwait(true);
        ApplyBackgroundHostAutostart(prefs.BackgroundHostAtLogon);
        DialogResult = true;
        Close();
    }

    private void ApplyBackgroundHostAutostart(bool enabled)
    {
        if (enabled)
        {
            var exe = HostLogonAutostart.FindHostExecutable();
            if (exe is null)
            {
                MessageBox.Show(
                    this,
                    "Explorer.Host.exe was not found next to Explorer Workbench, so the sign-in task was not registered.",
                    "Background host",
                    MessageBoxButton.OK,
                    MessageBoxImage.Warning);
                return;
            }

            if (!HostLogonAutostart.TryRegister(exe, out var error))
            {
                MessageBox.Show(this, error, "Background host", MessageBoxButton.OK, MessageBoxImage.Warning);
            }

            return;
        }

        if (!HostLogonAutostart.TryUnregister(out var unregisterError))
        {
            MessageBox.Show(this, unregisterError, "Background host", MessageBoxButton.OK, MessageBoxImage.Warning);
        }
    }

    private void OnCancel(object sender, RoutedEventArgs e)
    {
        _vm.Theme = _originalTheme;
    }
}