using System.Diagnostics;
using System.IO;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Media;
using System.Windows.Media.Animation;

namespace DeskCoreSetup;

public partial class MainWindow : Window
{
    private readonly bool _uninstall;
    private int _page;
    private bool _busy;
    private bool _done;
    private string? _installedExe;

    public MainWindow(bool uninstall)
    {
        InitializeComponent();
        _uninstall = uninstall;
        VersionText.Text = $"Version {Installer.Version}";
        LicenseText.Text = Installer.LicenseText;

        DirBox.Text = Installer.InstalledDir ?? Installer.DefaultDir;
        DesktopLinkBox.IsChecked = Installer.InstalledDir is null || Installer.DesktopLinkExists;
        AutostartBox.IsChecked = Installer.AutostartEnabled;

        if (Installer.InstalledDir is null && Installer.LegacyInstallDir is not null)
        {
            UpdateHint.Visibility = Visibility.Visible;
            UpdateHintText.Text = "Die bisherige Version „DeskHub“ wird durch DeskCore ersetzt. Deine Kategorien und Einstellungen werden übernommen.";
        }
        else if (Installer.InstalledDir is not null)
        {
            UpdateHint.Visibility = Visibility.Visible;
            UpdateHintText.Text = Installer.InstalledVersion == Installer.Version
                ? $"DeskCore {Installer.Version} ist bereits installiert und wird neu installiert. Deine Kategorien und Einstellungen bleiben erhalten."
                : $"Die vorhandene Installation (Version {Installer.InstalledVersion}) wird durch Version {Installer.Version} ersetzt. Deine Kategorien und Einstellungen bleiben erhalten.";
        }

        if (_uninstall)
        {
            Title = WindowTitle.Text = "DeskCore deinstallieren";
            Steps.Visibility = Visibility.Collapsed;
            ShowOnly(PageUninstall);
            NextButton.Content = "Deinstallieren";
            BackButton.Visibility = Visibility.Collapsed;
            LoadDataInfo();
        }
        else ShowPage(0);
    }

    // ---------- Seiten ----------

    private void ShowOnly(UIElement page)
    {
        foreach (var p in new UIElement[] { PageWelcome, PageLicense, PageOptions, PageProgress, PageUninstall })
            p.Visibility = p == page ? Visibility.Visible : Visibility.Collapsed;
    }

    private void ShowPage(int page)
    {
        _page = page;
        ShowOnly(page switch { 0 => PageWelcome, 1 => PageLicense, 2 => PageOptions, _ => PageProgress });

        var steps = new[] { Step0, Step1, Step2, Step3 };
        for (int i = 0; i < steps.Length; i++)
        {
            var label = ((string)steps[i].Tag ?? (string)(steps[i].Tag = steps[i].Text));
            steps[i].Text = i < page || (_done && i == page) ? $"✓  {label}" : label;
            steps[i].FontWeight = i == page ? FontWeights.SemiBold : FontWeights.Normal;
            steps[i].Foreground = (Brush)FindResource(i == page ? "TextBrush" : i < page ? "TextSecondaryBrush" : "TextTertiaryBrush");
        }

        BackButton.Visibility = page is 1 or 2 ? Visibility.Visible : Visibility.Hidden;
        NextButton.Content = page switch { 2 => "Installieren", 3 => "Fertigstellen", _ => "Weiter" };
        NextButton.IsEnabled = page != 1 || AcceptLicense.IsChecked == true;
    }

    private void AcceptLicense_Click(object sender, RoutedEventArgs e) => NextButton.IsEnabled = AcceptLicense.IsChecked == true;

    private void Back_Click(object sender, RoutedEventArgs e)
    {
        if (!_busy && _page > 0) ShowPage(_page - 1);
    }

    private async void Next_Click(object sender, RoutedEventArgs e)
    {
        if (_busy) return;

        if (_uninstall)
        {
            if (_done) { Close(); return; }
            await RunUninstall();
            return;
        }

        switch (_page)
        {
            case 0: ShowPage(1); break;
            case 1 when AcceptLicense.IsChecked == true: ShowPage(2); break;
            case 2:
                var dir = DirBox.Text.Trim();
                if (!Path.IsPathFullyQualified(dir) || dir.IndexOfAny(Path.GetInvalidPathChars()) >= 0)
                {
                    MessageBox.Show(this, "Bitte einen gültigen Ordner angeben, z. B. C:\\Programme\\DeskCore.", "DeskCore Setup");
                    return;
                }
                await RunInstall(dir);
                break;
            case 3:
                if (LaunchBox.IsChecked == true && _installedExe is not null)
                    Process.Start(new ProcessStartInfo(_installedExe) { UseShellExecute = true });
                Close();
                break;
        }
    }

    private void ChangeDir_Click(object sender, RoutedEventArgs e)
    {
        var dlg = new Microsoft.Win32.OpenFolderDialog { Title = "Installationsordner wählen" };
        if (dlg.ShowDialog(this) != true) return;
        var chosen = dlg.FolderName;
        // wie bei üblichen Installern: Unterordner "DeskCore" anhängen
        DirBox.Text = Path.GetFileName(chosen.TrimEnd('\\')).Equals("DeskCore", StringComparison.OrdinalIgnoreCase)
            ? chosen : Path.Combine(chosen, "DeskCore");
    }

    // ---------- Installation ----------

    private async Task RunInstall(string dir)
    {
        _busy = true;
        ShowPage(3);
        SetButtons(false);
        var progress = new Progress<(double Value, string Text)>(p => SetProgress(p.Value, p.Text));
        bool desktop = DesktopLinkBox.IsChecked == true, autostart = AutostartBox.IsChecked == true;
        try
        {
            await Task.Run(() => Installer.Install(dir, desktop, autostart, progress));
            _installedExe = Path.Combine(dir, Installer.ExeName);
            _done = true;
            ProgressTitle.Text = "Installation abgeschlossen";
            ProgressText.Text = $"DeskCore wurde in {dir} installiert. Du findest es im Startmenü" + (desktop ? " und auf dem Desktop." : ".");
            DoneText.Text = "Alles bereit!";
            DonePanel.Visibility = Visibility.Visible;
            ShowPage(3);
        }
        catch (Exception ex)
        {
            ProgressTitle.Text = "Installation fehlgeschlagen";
            ProgressText.Text = ex.Message;
            ProgressText.Foreground = (Brush)FindResource("DangerBrush");
            NextButton.Content = "Schließen";
            _installedExe = null;
        }
        _busy = false;
        NextButton.IsEnabled = true;
        CloseButton.IsEnabled = true;
        BackButton.Visibility = Visibility.Hidden;
        CancelButton.Visibility = Visibility.Collapsed;
    }

    // ---------- Deinstallation ----------

    private async void LoadDataInfo()
    {
        var root = Installer.DataDirs[0];
        if (!Directory.Exists(root))
        {
            DataInfo.Text = "Es wurden keine Kategorien gefunden.";
            return;
        }
        DataInfo.Text = $"Sie liegen in {root}. Größe wird berechnet …";
        var size = await Task.Run(Installer.DataSize);
        DataInfo.Text = $"Sie liegen in {root} ({Installer.FormatSize(size)}) und bleiben dort, falls du DeskCore später wieder installierst.";
    }

    private void RemoveDataBox_Click(object sender, RoutedEventArgs e) =>
        RemoveDataWarning.Visibility = RemoveDataBox.IsChecked == true ? Visibility.Visible : Visibility.Collapsed;

    private async Task RunUninstall()
    {
        _busy = true;
        bool removeData = RemoveDataBox.IsChecked == true;
        ShowOnly(PageProgress);
        ProgressTitle.Text = "DeskCore wird entfernt …";
        LaunchBox.Visibility = Visibility.Collapsed;
        SetButtons(false);
        var progress = new Progress<(double Value, string Text)>(p => SetProgress(p.Value, p.Text));
        try
        {
            await Task.Run(() => Installer.Uninstall(removeData, progress));
            ProgressTitle.Text = "Deinstallation abgeschlossen";
            ProgressText.Text = removeData
                ? "DeskCore, deine Kategorien und Einstellungen wurden entfernt (die Daten liegen im Papierkorb)."
                : "DeskCore wurde entfernt. Deine Kategorien liegen weiterhin in " + Installer.DataDirs[0] + ".";
            DoneText.Text = "Fertig";
            DonePanel.Visibility = Visibility.Visible;
        }
        catch (Exception ex)
        {
            ProgressTitle.Text = "Deinstallation fehlgeschlagen";
            ProgressText.Text = ex.Message;
        }
        _done = true;
        _busy = false;
        CloseButton.IsEnabled = true;
        NextButton.Content = "Schließen";
        NextButton.IsEnabled = true;
        CancelButton.Visibility = Visibility.Collapsed;
    }

    // ---------- Helfer ----------

    private void SetButtons(bool enabled)
    {
        NextButton.IsEnabled = enabled;
        BackButton.IsEnabled = enabled;
        CancelButton.IsEnabled = enabled;
        CloseButton.IsEnabled = enabled;
    }

    private void SetProgress(double value, string text)
    {
        if (!_done) ProgressText.Text = text;
        var target = Math.Max(0, ProgressTrack.ActualWidth * value);
        ProgressFill.BeginAnimation(WidthProperty,
            new DoubleAnimation(target, TimeSpan.FromMilliseconds(250)) { EasingFunction = new CubicEase() });
    }

    private void Minimize_Click(object sender, RoutedEventArgs e) => WindowState = WindowState.Minimized;

    private void Cancel_Click(object sender, RoutedEventArgs e)
    {
        if (_busy) return;
        if (!_done && !_uninstall && _page > 0 &&
            MessageBox.Show(this, "Installation wirklich abbrechen?", "DeskCore Setup", MessageBoxButton.YesNo, MessageBoxImage.Question) != MessageBoxResult.Yes)
            return;
        Close();
    }

    protected override void OnClosing(System.ComponentModel.CancelEventArgs e)
    {
        if (_busy) e.Cancel = true; // während der Installation nicht schließen
        base.OnClosing(e);
    }
}