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

namespace GitManagerSetup;

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

    private const int PageNumOptions = 1;
    private const int PageNumProgress = 2;

    public MainWindow(SetupMode mode)
    {
        InitializeComponent();
        _mode = mode;
        VersionText.Text = $"Version {Installer.Version}";

        var installed = Installer.InstalledDir;
        DirBox.Text = installed ?? Installer.DefaultDir;
        DesktopLinkBox.IsChecked = installed is null || Installer.DesktopLinkExists;

        if (installed is not null)
        {
            UpdateHint.Visibility = Visibility.Visible;
            UpdateHintText.Text = Installer.InstalledVersion == Installer.Version
                ? $"Git Manager GUI {Installer.Version} ist bereits installiert und wird neu installiert. Zugangsdaten und Einstellungen bleiben erhalten."
                : $"Die vorhandene Installation{(Installer.InstalledVersion is { } v ? $" (Version {v})" : "")} wird durch Version {Installer.Version} ersetzt. Zugangsdaten und Einstellungen bleiben erhalten.";
        }
        if (Installer.IsRunning(installed)) RunningHint.Visibility = Visibility.Visible;

        switch (mode)
        {
            case SetupMode.Uninstall:
                Title = WindowTitle.Text = "Git Manager GUI deinstallieren";
                Steps.Visibility = Visibility.Collapsed;
                ShowOnly(PageUninstall);
                NextButton.Content = "Deinstallieren";
                BackButton.Visibility = Visibility.Collapsed;
                LoadDataInfo();
                break;
            case SetupMode.Update:
                // aus der App heraus: ohne Rückfragen direkt aktualisieren und danach wieder starten
                Title = WindowTitle.Text = "Git Manager GUI wird aktualisiert";
                Steps.Visibility = Visibility.Collapsed;
                Loaded += async (_, _) => await RunInstall(DirBox.Text, DesktopLinkBox.IsChecked == true, update: true);
                ShowOnly(PageProgress);
                ProgressTitle.Text = "Git Manager GUI wird aktualisiert …";
                BackButton.Visibility = Visibility.Hidden;
                break;
            default:
                ShowPage(0);
                break;
        }
    }

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

    private UIElement? _shownPage;

    /// <summary>Seite wechseln – mit kurzem Einblenden von rechts.</summary>
    private void ShowOnly(UIElement page)
    {
        foreach (var p in new UIElement[] { PageWelcome, PageOptions, PageProgress, PageUninstall })
            p.Visibility = p == page ? Visibility.Visible : Visibility.Collapsed;
        if (page == _shownPage) return;
        _shownPage = page;

        var ease = new CubicEase { EasingMode = EasingMode.EaseOut };
        var slide = new TranslateTransform(18, 0);
        page.RenderTransform = slide;
        slide.BeginAnimation(TranslateTransform.XProperty, new DoubleAnimation(18, 0, TimeSpan.FromMilliseconds(260)) { EasingFunction = ease });
        page.BeginAnimation(OpacityProperty, new DoubleAnimation(0, 1, TimeSpan.FromMilliseconds(220)));
    }

    // Farben der Schritt-Anzeige in der (immer dunklen) Seitenleiste – Cyan wie in der App
    private static readonly Brush StepDoneFill = Frozen(Color.FromRgb(0x58, 0xD5, 0xFF));
    private static readonly Brush StepDoneGlyph = Frozen(Color.FromRgb(0x04, 0x10, 0x1F));
    private static readonly Brush StepCurrentFill = Brushes.White;
    private static readonly Brush StepCurrentText = Frozen(Color.FromRgb(0x13, 0x30, 0x5C));
    private static readonly Brush StepUpcoming = Frozen(Color.FromRgb(0x70, 0x83, 0xA4));
    private static readonly Brush StepUpcomingStroke = Frozen(Color.FromRgb(0x3A, 0x4E, 0x72));
    private static readonly Brush StepDoneText = Frozen(Color.FromRgb(0xAE, 0xBD, 0xD8));
    private static readonly Brush StepLineIdle = Frozen(Color.FromRgb(0x24, 0x36, 0x58));

    private static Brush Frozen(Color c)
    {
        var b = new SolidColorBrush(c);
        b.Freeze();
        return b;
    }

    private void UpdateSteps(int page)
    {
        var dots = new[] { Dot0, Dot1, Dot2 };
        var nums = new[] { Num0, Num1, Num2 };
        var labels = new[] { Label0, Label1, Label2 };
        var lines = new[] { Line0, Line1 };
        var iconFont = (FontFamily)FindResource("IconFont");
        var uiFont = (FontFamily)FindResource("UiFont");

        for (int i = 0; i < dots.Length; i++)
        {
            bool done = i < page || (_done && i == page);
            bool current = i == page && !done;
            dots[i].Background = done ? StepDoneFill : current ? StepCurrentFill : Brushes.Transparent;
            dots[i].BorderBrush = done ? StepDoneFill : current ? StepCurrentFill : StepUpcomingStroke;
            nums[i].Text = done ? "" : (i + 1).ToString();
            nums[i].FontFamily = done ? iconFont : uiFont;
            nums[i].FontSize = done ? 11 : 12;
            nums[i].Foreground = done ? StepDoneGlyph : current ? StepCurrentText : StepUpcoming;
            labels[i].Foreground = current ? Brushes.White : done ? StepDoneText : StepUpcoming;
            labels[i].FontWeight = current ? FontWeights.SemiBold : FontWeights.Normal;
        }
        for (int i = 0; i < lines.Length; i++)
            lines[i].Background = i < page ? StepDoneFill : StepLineIdle;
    }

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

        BackButton.Visibility = page == PageNumOptions ? Visibility.Visible : Visibility.Hidden;
        NextButton.Content = page switch
        {
            PageNumOptions => "Installieren",
            PageNumProgress => "Fertigstellen",
            _ => "Weiter",
        };
    }

    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 (_mode == SetupMode.Uninstall)
        {
            if (_done) { Close(); return; }
            await RunUninstall();
            return;
        }
        if (_mode == SetupMode.Update)
        {
            Close(); // nur nach einem Fehler erreichbar
            return;
        }

        switch (_page)
        {
            case 0: ShowPage(PageNumOptions); break;
            case PageNumOptions:
                var dir = DirBox.Text.Trim();
                if (!IsFullPath(dir) || dir.IndexOfAny(Path.GetInvalidPathChars()) >= 0)
                {
                    await Frage("Ungültiger Ordner", "Bitte einen vollständigen Ordner angeben, z. B. C:\\Programme\\Git Manager GUI.", "OK");
                    return;
                }
                if (dir.TrimEnd('\\', '/').Length > Installer.MaxDirLength)
                {
                    await Frage("Ordnerpfad zu lang",
                        $"Der Pfad hat {dir.TrimEnd('\\', '/').Length} Zeichen, Windows erlaubt hier höchstens {Installer.MaxDirLength}. " +
                        "Bitte einen kürzeren Ordner wählen.", "OK");
                    return;
                }
                await RunInstall(dir, DesktopLinkBox.IsChecked == true, update: false);
                break;
            case PageNumProgress:
                // Start im Hintergrund: Process.Start kann blockieren, solange Windows
                // die EXE prüft – das Fenster darf dabei nie einfrieren
                if (LaunchBox.IsChecked == true)
                {
                    _busy = true;
                    NextButton.IsEnabled = false;
                    NextButton.Content = "Wird gestartet …";
                    await Task.Run(StartApp);
                    _busy = false;
                }
                Close();
                break;
        }
    }

    private void ChangeDir_Click(object sender, RoutedEventArgs e)
    {
        using var dlg = new System.Windows.Forms.FolderBrowserDialog
        {
            Description = "Installationsordner wählen",
            SelectedPath = Directory.Exists(DirBox.Text) ? DirBox.Text : Environment.GetFolderPath(Environment.SpecialFolder.LocalApplicationData),
            ShowNewFolderButton = true,
        };
        if (dlg.ShowDialog() != System.Windows.Forms.DialogResult.OK) return;
        var chosen = dlg.SelectedPath;
        // wie bei üblichen Installern: Unterordner "Git Manager GUI" anhängen
        DirBox.Text = Path.GetFileName(chosen.TrimEnd('\\')).Equals(Installer.AppName, StringComparison.OrdinalIgnoreCase)
            ? chosen : Path.Combine(chosen, Installer.AppName);
    }

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

    private async Task RunInstall(string dir, bool desktop, bool update)
    {
        _busy = true;
        if (!update) ShowPage(PageNumProgress);
        SetButtons(false);
        var progress = new Progress<(double Value, string Text)>(p => SetProgress(p.Value, p.Text));
        try
        {
            await Task.Run(() => Installer.Install(dir, desktop, progress, waitForExit: update));
            _installedExe = Path.Combine(dir, Installer.ExeName);
            _done = true;

            if (update)
            {
                ShowSuccess("Update abgeschlossen", $"Git Manager GUI {Installer.Version} wird gestartet …");
                StartApp();
                _busy = false;
                var timer = new DispatcherTimer { Interval = TimeSpan.FromSeconds(1.5) };
                timer.Tick += (_, _) => { timer.Stop(); Close(); };
                timer.Start();
                return;
            }

            ShowSuccess("Alles bereit!", "Git Manager GUI ist installiert. Du findest es im Startmenü" + (desktop ? " und auf dem Desktop." : "."));
            DonePanel.Visibility = Visibility.Visible;
            ShowPage(PageNumProgress);
        }
        catch (Exception ex)
        {
            ProgressTitle.Text = update ? "Update fehlgeschlagen" : "Installation fehlgeschlagen";
            ProgressBarPanel.Visibility = Visibility.Collapsed;
            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;
    }

    /// <summary>Fortschritt ausblenden und den Haken mit kurzem "Aufploppen" zeigen.</summary>
    private void ShowSuccess(string title, string text)
    {
        ProgressBarPanel.Visibility = Visibility.Collapsed;
        ProgressTitle.Text = title;
        ProgressText.Text = text;
        SuccessIcon.Visibility = Visibility.Visible;
        var pop = new DoubleAnimation(0.4, 1, TimeSpan.FromMilliseconds(420)) { EasingFunction = new BackEase { EasingMode = EasingMode.EaseOut, Amplitude = 0.5 } };
        SuccessScale.BeginAnimation(ScaleTransform.ScaleXProperty, pop);
        SuccessScale.BeginAnimation(ScaleTransform.ScaleYProperty, pop);
        SuccessIcon.BeginAnimation(OpacityProperty, new DoubleAnimation(0, 1, TimeSpan.FromMilliseconds(200)));
    }

    private void StartApp()
    {
        if (_installedExe is null || !File.Exists(_installedExe)) return;
        try
        {
            Process.Start(new ProcessStartInfo(_installedExe)
            {
                UseShellExecute = true,
                WorkingDirectory = Path.GetDirectoryName(_installedExe)!,
            });
        }
        catch { }
    }

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

    private async void LoadDataInfo()
    {
        var root = Installer.DataDir;
        if (!Directory.Exists(root))
        {
            DataInfo.Text = "Es wurden keine App-Daten gefunden.";
            RemoveDataBox.IsEnabled = false;
            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 stehen wieder bereit, falls du Git Manager GUI später neu 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 = "Git Manager GUI 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));
            ShowSuccess("Git Manager GUI wurde entfernt", removeData
                ? "Programm, Zugangsdaten und Einstellungen wurden entfernt (die Daten liegen im Papierkorb)."
                : "Deine Zugangsdaten und Einstellungen liegen weiterhin in " + Installer.DataDir + " – falls du Git Manager GUI später wieder installierst.");
        }
        catch (Exception ex)
        {
            ProgressTitle.Text = "Deinstallation fehlgeschlagen";
            ProgressBarPanel.Visibility = Visibility.Collapsed;
            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) return;
        ProgressText.Text = text;
        PercentText.Text = $"{(int)Math.Round(value * 100)} %";
        _progress = value;
        AnimateProgress();
    }

    private double _progress;

    private void AnimateProgress()
    {
        var target = Math.Max(0, ProgressTrack.ActualWidth * _progress);
        ProgressFill.BeginAnimation(WidthProperty,
            new DoubleAnimation(target, TimeSpan.FromMilliseconds(250)) { EasingFunction = new CubicEase() });
    }

    // Kommt der erste Wert, bevor die Seite fertig angeordnet ist (Breite 0), nachträglich richtig setzen
    private void ProgressTrack_SizeChanged(object sender, SizeChangedEventArgs e) => AnimateProgress();

    private static bool IsFullPath(string p) =>
        p.Length >= 3 && char.IsLetter(p[0]) && p[1] == ':' && (p[2] == '\\' || p[2] == '/');

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

    private async void Cancel_Click(object sender, RoutedEventArgs e)
    {
        if (_busy || _dialog is not null) return;
        if (!_done && _mode == SetupMode.Install && _page > 0)
        {
            bool abbrechen = await Frage("Installation abbrechen?",
                "Git Manager GUI wird nicht installiert. Du kannst das Setup später jederzeit erneut starten.",
                "Ja, abbrechen", "Weiter installieren", "\uE897");
            if (!abbrechen) return;
        }
        Close();
    }

    // ---------- eigene Rückfragen im Setup-Look ----------

    private TaskCompletionSource<bool>? _dialog;

    /// <summary>
    /// Zeigt eine Rückfrage über dem Fenster. Mit <paramref name="zurueck"/>: zwei Knöpfe –
    /// der hervorgehobene ist der sichere Weg zurück (liefert false), der andere bestätigt (true).
    /// Ohne: nur ein Hinweis mit einem Knopf (liefert true).
    /// </summary>
    private Task<bool> Frage(string titel, string text, string bestaetigen, string? zurueck = null, string symbol = "\uE7BA")
    {
        _dialog?.TrySetResult(false);
        _dialog = new TaskCompletionSource<bool>();
        DialogTitle.Text = titel;
        DialogText.Text = text;
        DialogIcon.Text = symbol;
        if (zurueck is null)
        {
            DialogSecondary.Visibility = Visibility.Collapsed;
            DialogPrimary.Content = bestaetigen;
        }
        else
        {
            DialogSecondary.Visibility = Visibility.Visible;
            DialogSecondary.Content = bestaetigen;
            DialogPrimary.Content = zurueck;
        }

        DialogOverlay.Visibility = Visibility.Visible;
        var ein = new DoubleAnimation(0, 1, TimeSpan.FromMilliseconds(160));
        DialogOverlay.BeginAnimation(OpacityProperty, ein);
        var groesse = new DoubleAnimation(0.94, 1, TimeSpan.FromMilliseconds(220)) { EasingFunction = new CubicEase { EasingMode = EasingMode.EaseOut } };
        DialogScale.BeginAnimation(ScaleTransform.ScaleXProperty, groesse);
        DialogScale.BeginAnimation(ScaleTransform.ScaleYProperty, groesse);
        DialogPrimary.Focus();
        return _dialog.Task;
    }

    private void SchliesseFrage(bool ergebnis)
    {
        if (_dialog is null) return;
        var tcs = _dialog;
        _dialog = null;
        DialogOverlay.Visibility = Visibility.Collapsed;
        tcs.TrySetResult(ergebnis);
    }

    // hervorgehobener Knopf: bei Rückfragen "zurück" (false), beim reinen Hinweis "OK" (true)
    private void DialogPrimary_Click(object sender, RoutedEventArgs e) =>
        SchliesseFrage(DialogSecondary.Visibility != Visibility.Visible);

    private void DialogSecondary_Click(object sender, RoutedEventArgs e) => SchliesseFrage(true);

    protected override void OnPreviewKeyDown(System.Windows.Input.KeyEventArgs e)
    {
        // solange die Rückfrage offen ist: Enter = hervorgehobener Knopf, Esc = zurück
        if (_dialog is not null)
        {
            if (e.Key == System.Windows.Input.Key.Escape) { SchliesseFrage(DialogSecondary.Visibility != Visibility.Visible); e.Handled = true; return; }
            if (e.Key == System.Windows.Input.Key.Enter) { DialogPrimary_Click(this, new RoutedEventArgs()); e.Handled = true; return; }
        }
        base.OnPreviewKeyDown(e);
    }

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