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

namespace DeskCore;

/// <summary>Start-Gruppen: ein Klick startet mehrere Programme nacheinander.</summary>
public partial class MainWindow
{
    private LaunchGroupItem? CurrentGroup => LaunchList.SelectedItem as LaunchGroupItem;

    /// <summary>Kategorie-Dialog von außen (z. B. "Neue Box hier" auf dem Desktop).</summary>
    public string? CreateCategoryInteractive() => NewCategory();

    private static string DelayText(LaunchGroup g) =>
        g.DelaySeconds <= 0 ? "gleichzeitig" : $"{g.DelaySeconds:0.#} s Abstand";

    /// <summary>Wo liegt ein Element? (für Tooltip/Listenansicht)</summary>
    private static string LocationOf(string path)
    {
        var dir = Path.GetDirectoryName(path) ?? "";
        if (Storage.IsDesktopDir(dir)) return DesktopName;
        return Storage.IsInStorage(path) ? Path.GetFileName(dir) : dir;
    }

    private void LoadGroupIcons(LaunchGroup g)
    {
        var items = g.Items.Select(p => new IconItem { Path = p, Category = LocationOf(p) }).ToList();
        HeaderText.Text = g.Name;
        int missing = items.Count(i => !File.Exists(i.Path) && !Directory.Exists(i.Path));
        SubText.Text = $"{Plural(items.Count, "Programm", "Programme")}  ·  {DelayText(g)}" +
                       (missing > 0 ? $"  ·  ⚠ {missing} nicht mehr vorhanden" : "");
        SetEmpty("", "Noch leer",
            "Ziehe Programme hierher oder auf die Gruppe links – oder Rechtsklick auf ein Icon → „Zur Start-Gruppe hinzufügen“.");

        // Reihenfolge = Startreihenfolge, deshalb hier nicht sortieren
        var px = IconPixels;
        foreach (var item in items) IconLoader.Load(item, px);
        IconList.ItemsSource = items;

        EmptyState.Visibility = items.Count == 0 ? Visibility.Visible : Visibility.Collapsed;
        CategoryCommands.Visibility = Visibility.Collapsed;
        InfoBar.Visibility = Visibility.Collapsed;
        GroupCommands.Visibility = Visibility.Visible;
    }

    private void SelectGroup(LaunchGroup g)
    {
        var item = LaunchList.Items.OfType<LaunchGroupItem>().FirstOrDefault(x => x.Group == g);
        if (item is not null) LaunchList.SelectedItem = item;
    }

    // ---------- Starten ----------

    /// <summary>Startet alle Programme der Gruppe nacheinander (mit eingestelltem Abstand).</summary>
    public async void LaunchGroupNow(LaunchGroup g)
    {
        if (g.Items.Count == 0)
        {
            ShowToast($"„{g.Name}“ ist noch leer", "", info: true);
            return;
        }
        int started = 0;
        var problems = new List<string>();
        var items = g.Items.ToList();
        for (int i = 0; i < items.Count; i++)
        {
            if (i > 0 && g.DelaySeconds > 0) await Task.Delay(TimeSpan.FromSeconds(g.DelaySeconds));
            var p = items[i];
            if (!File.Exists(p) && !Directory.Exists(p)) { problems.Add($"„{Storage.DisplayName(p)}“ gibt es nicht mehr"); continue; }
            try
            {
                Process.Start(new ProcessStartInfo(p) { UseShellExecute = true });
                started++;
            }
            catch (Exception ex) { problems.Add($"„{Storage.DisplayName(p)}“: {ex.Message}"); }
        }

        var text = $"„{g.Name}“: {Plural(started, "Programm", "Programme")} gestartet" +
                   (problems.Count > 0 ? $" · {problems.Count} nicht" : "");
        if (IsVisible && IsActive) ShowToast(text, problems.Count > 0 ? "" : "", info: problems.Count > 0);
        else App.TrayIcon?.Notify(g.Name, problems.Count > 0 ? text + "\n" + string.Join("\n", problems.Take(3)) : text);
    }

    /// <summary>Für die Befehlszeile und Desktop-Verknüpfungen: DeskCore.exe --launch "Name".</summary>
    public bool LaunchGroupByName(string name)
    {
        var g = S.LaunchGroups.FirstOrDefault(x => string.Equals(x.Name, name, StringComparison.OrdinalIgnoreCase));
        if (g is null)
        {
            App.TrayIcon?.Notify("Start-Gruppe nicht gefunden", $"Es gibt keine Start-Gruppe „{name}“.");
            return false;
        }
        LaunchGroupNow(g);
        return true;
    }

    private void LaunchCurrentGroup_Click(object sender, RoutedEventArgs e)
    {
        if (CurrentGroup is { } g) LaunchGroupNow(g.Group);
    }

    private void LaunchGroupPlay_Click(object sender, RoutedEventArgs e)
    {
        if ((sender as FrameworkElement)?.Tag is LaunchGroupItem g) LaunchGroupNow(g.Group);
        e.Handled = true;
    }

    // ---------- Anlegen / Bearbeiten ----------

    /// <summary>Dialog für Name, Startabstand und Farbe. Gibt null bei Abbruch zurück.</summary>
    private (string Name, double Delay, string? Color)? LaunchGroupDialog(string title, string primary, LaunchGroup? existing)
    {
        var res = Application.Current.Resources;
        var panel = new StackPanel();
        TextBlock Label(string t, double top = 16) => new()
        {
            Text = t, Margin = new Thickness(0, top, 0, 8), FontWeight = FontWeights.SemiBold, FontSize = 13,
        };

        panel.Children.Add(Label("Name", 0));
        var nameBox = new TextBox { Text = existing?.Name ?? "" };
        panel.Children.Add(nameBox);

        panel.Children.Add(Label("Abstand zwischen den Programmen"));
        var delayText = new TextBlock { VerticalAlignment = VerticalAlignment.Center, Width = 110, Foreground = (Brush)res["TextSecondaryBrush"] };
        var slider = new Slider { Minimum = 0, Maximum = 10, TickFrequency = 0.5, IsSnapToTickEnabled = true, Value = existing?.DelaySeconds ?? 1 };
        void UpdateDelay() => delayText.Text = slider.Value <= 0 ? "gleichzeitig" : $"{slider.Value:0.#} Sekunden";
        slider.ValueChanged += (_, _) => UpdateDelay();
        UpdateDelay();
        var row = new DockPanel();
        DockPanel.SetDock(delayText, Dock.Right);
        row.Children.Add(delayText);
        row.Children.Add(slider);
        panel.Children.Add(row);
        panel.Children.Add(new TextBlock
        {
            Text = "Etwas Abstand hilft, wenn Programme beim Start viel Leistung brauchen.", FontSize = 12, Margin = new Thickness(0, 4, 0, 0),
            TextWrapping = TextWrapping.Wrap, Foreground = (Brush)res["TextTertiaryBrush"],
        });

        panel.Children.Add(Label("Farbe"));
        string? color = existing?.Color;
        var swatches = new WrapPanel();
        var none = new RadioButton
        {
            Style = (Style)res["SwatchRadio"], GroupName = "lgcolor", ToolTip = "Akzentfarbe", Background = (Brush)res["AccentBrush"],
            IsChecked = color is null,
        };
        none.Checked += (_, _) => color = null;
        swatches.Children.Add(none);
        foreach (var (cname, hex) in CategoryColors.All)
        {
            var rb = new RadioButton
            {
                Style = (Style)res["SwatchRadio"], GroupName = "lgcolor", ToolTip = cname, Background = CategoryColors.Brush(hex),
                IsChecked = string.Equals(color, hex, StringComparison.OrdinalIgnoreCase),
            };
            rb.Checked += (_, _) => color = hex;
            swatches.Children.Add(rb);
        }
        panel.Children.Add(swatches);

        string? Validate()
        {
            var n = nameBox.Text.Trim();
            if (n.Length == 0) return "Bitte einen Namen eingeben.";
            if (n.Contains('"')) return "Der Name darf keine Anführungszeichen enthalten.";
            bool taken = S.LaunchGroups.Any(x => x != existing && string.Equals(x.Name, n, StringComparison.OrdinalIgnoreCase));
            return taken ? "Eine Start-Gruppe mit diesem Namen gibt es schon." : null;
        }

        if (!Dialog.Show(this, title, panel, primary, "Abbrechen", Validate, nameBox, width: 470)) return null;
        return (nameBox.Text.Trim(), slider.Value, color);
    }

    private LaunchGroup? NewLaunchGroup(IEnumerable<string>? initialItems = null)
    {
        var form = LaunchGroupDialog("Neue Start-Gruppe", "Erstellen", null);
        if (form is null) return null;
        var g = new LaunchGroup { Name = form.Value.Name, DelaySeconds = form.Value.Delay, Color = form.Value.Color };
        S.LaunchGroups.Add(g);
        if (initialItems is not null) AddPathsToGroup(g, initialItems, toast: false);
        S.Save();

        var entry = new UndoEntry($"Start-Gruppe „{g.Name}“ erstellen");
        entry.Add(() => { S.LaunchGroups.Remove(g); S.Save(); return null; });
        Undo.Push(entry);
        Refresh();
        return g;
    }

    private void NewLaunchGroup_Click(object sender, RoutedEventArgs e)
    {
        if (NewLaunchGroup() is not { } g) return;
        ShowBrowse();
        SelectGroup(g);
        ShowToast($"Start-Gruppe „{g.Name}“ erstellt – jetzt Programme hineinziehen", "", undoable: true);
    }

    private void EditLaunchGroup(LaunchGroup g)
    {
        var form = LaunchGroupDialog("Start-Gruppe bearbeiten", "Speichern", g);
        if (form is null) return;
        var before = (g.Name, g.DelaySeconds, g.Color);
        (g.Name, g.DelaySeconds, g.Color) = form.Value;
        S.Save();
        var entry = new UndoEntry($"Start-Gruppe „{before.Name}“ bearbeiten");
        entry.Add(() => { (g.Name, g.DelaySeconds, g.Color) = before; S.Save(); return null; });
        Undo.Push(entry);
        Refresh();
        if (before.Name != g.Name)
            ShowToast("Gespeichert – eine vorhandene Desktop-Verknüpfung bitte neu anlegen (sie nutzt noch den alten Namen)", "", info: true);
        else ShowToast("Start-Gruppe gespeichert", undoable: true);
    }

    private void EditLaunchGroup_Click(object sender, RoutedEventArgs e)
    {
        if (CurrentGroup is { } g) EditLaunchGroup(g.Group);
    }

    private void DeleteLaunchGroup(LaunchGroup g)
    {
        if (!Dialog.Confirm(this, "Start-Gruppe löschen?",
                $"„{g.Name}“ wird entfernt. Die Programme selbst bleiben unverändert.", "Löschen"))
            return;
        int index = S.LaunchGroups.IndexOf(g);
        S.LaunchGroups.Remove(g);
        S.Save();
        var entry = new UndoEntry($"Start-Gruppe „{g.Name}“ löschen");
        entry.Add(() => { S.LaunchGroups.Insert(Math.Min(index, S.LaunchGroups.Count), g); S.Save(); return null; });
        Undo.Push(entry);
        Refresh();
        ShowToast($"Start-Gruppe „{g.Name}“ gelöscht", "", undoable: true);
    }

    private void DeleteLaunchGroup_Click(object sender, RoutedEventArgs e)
    {
        if (CurrentGroup is { } g) DeleteLaunchGroup(g.Group);
    }

    private void MoveLaunchGroup(LaunchGroup g, int delta)
    {
        int i = S.LaunchGroups.IndexOf(g), j = i + delta;
        if (i < 0 || j < 0 || j >= S.LaunchGroups.Count) return;
        (S.LaunchGroups[i], S.LaunchGroups[j]) = (S.LaunchGroups[j], S.LaunchGroups[i]);
        S.Save();
        Refresh();
    }

    // ---------- Inhalt ----------

    /// <summary>
    /// Desktop-Icons, die schon in einer Kategorie gesichert sind, werden durch die gesicherte Kopie ersetzt –
    /// so funktioniert die Gruppe auch noch, wenn das Icon später vom Desktop gelöscht wird.
    /// </summary>
    private static string ResolveForGroup(string path)
    {
        if (Storage.IsInStorage(path)) return path;
        foreach (var c in Storage.Categories())
            if (Storage.Entries(Storage.CategoryPath(c)).FirstOrDefault(e => Storage.SameItem(e, path)) is { } saved)
                return saved;
        return path;
    }

    private void AddPathsToGroup(LaunchGroup g, IEnumerable<string> paths, bool toast = true)
    {
        int added = 0, dup = 0;
        foreach (var raw in paths)
        {
            var p = ResolveForGroup(raw);
            if (g.Items.Contains(p, StringComparer.OrdinalIgnoreCase)) { dup++; continue; }
            g.Items.Add(p);
            added++;
        }
        S.Save();
        if (!toast) return;
        Refresh();
        if (added == 0) ShowToast(dup == 1 ? "Das ist schon in der Gruppe" : "Alles schon in der Gruppe", "", info: true);
        else ShowToast($"{Plural(added, "Programm", "Programme")} zu „{g.Name}“ hinzugefügt", "");
    }

    private void RemoveFromGroup(LaunchGroup g, List<IconItem> sel)
    {
        var before = g.Items.ToList();
        foreach (var i in sel) g.Items.RemoveAll(p => string.Equals(p, i.Path, StringComparison.OrdinalIgnoreCase));
        S.Save();
        var entry = new UndoEntry($"Aus „{g.Name}“ entfernen");
        entry.Add(() => { g.Items = before; S.Save(); return null; });
        Undo.Push(entry);
        Refresh();
        ShowToast($"{Plural(sel.Count, "Programm", "Programme")} aus „{g.Name}“ entfernt – die Dateien bleiben erhalten", "", undoable: true);
    }

    private void MoveInGroup(LaunchGroup g, IconItem item, int delta)
    {
        int i = g.Items.FindIndex(p => string.Equals(p, item.Path, StringComparison.OrdinalIgnoreCase)), j = i + delta;
        if (i < 0 || j < 0 || j >= g.Items.Count) return;
        (g.Items[i], g.Items[j]) = (g.Items[j], g.Items[i]);
        S.Save();
        Refresh();
    }

    /// <summary>Kontextmenü der Icons, wenn eine Start-Gruppe angezeigt wird.</summary>
    private void FillGroupItemMenu(LaunchGroup g, List<IconItem> sel)
    {
        IconMenu.Items.Add(MenuItem("Öffnen", "", () => sel.ForEach(i => Open(i.Path)), bold: true, gesture: "Enter"));
        if (sel.Count == 1)
        {
            IconMenu.Items.Add(MenuItem("Dateispeicherort öffnen", "", () =>
                Process.Start("explorer.exe", $"/select,\"{sel[0].Path}\"")));
            IconMenu.Items.Add(new Separator());
            int idx = g.Items.FindIndex(p => string.Equals(p, sel[0].Path, StringComparison.OrdinalIgnoreCase));
            var up = MenuItem("Früher starten", "", () => MoveInGroup(g, sel[0], -1));
            up.IsEnabled = idx > 0;
            var down = MenuItem("Später starten", "", () => MoveInGroup(g, sel[0], +1));
            down.IsEnabled = idx >= 0 && idx < g.Items.Count - 1;
            IconMenu.Items.Add(up);
            IconMenu.Items.Add(down);
        }
        IconMenu.Items.Add(new Separator());
        IconMenu.Items.Add(MenuItem("Aus Start-Gruppe entfernen", "", () => RemoveFromGroup(g, sel), gesture: "Entf"));
    }

    /// <summary>Untermenü "Zur Start-Gruppe hinzufügen" (Haupt-Kontextmenü und Desktop-Boxen).</summary>
    public MenuItem LaunchGroupSubmenu(List<string> paths)
    {
        var menu = MenuItem("Zur Start-Gruppe hinzufügen", "", null);
        foreach (var g in S.LaunchGroups)
            menu.Items.Add(MenuItem(g.Name, "", () => AddPathsToGroup(g, paths)));
        if (menu.Items.Count > 0) menu.Items.Add(new Separator());
        menu.Items.Add(MenuItem("Neue Start-Gruppe…", "", () =>
        {
            if (NewLaunchGroup(paths) is { } g)
                ShowToast($"Start-Gruppe „{g.Name}“ mit {Plural(g.Items.Count, "Programm", "Programmen")} erstellt", "", undoable: true);
        }));
        return menu;
    }

    // ---------- Seitenleiste ----------

    private void LaunchList_ContextMenuOpening(object sender, ContextMenuEventArgs e)
    {
        if (FindParent<ListBoxItem>(e.OriginalSource as DependencyObject)?.DataContext is not LaunchGroupItem item)
        {
            e.Handled = true;
            return;
        }
        var g = item.Group;
        int idx = S.LaunchGroups.IndexOf(g);
        LaunchMenu.Items.Clear();
        LaunchMenu.Items.Add(MenuItem("Alle starten", "", () => LaunchGroupNow(g), bold: true));
        LaunchMenu.Items.Add(MenuItem("Bearbeiten…", "", () => EditLaunchGroup(g)));
        LaunchMenu.Items.Add(MenuItem("Verknüpfung auf den Desktop", "", () => CreateGroupShortcut(g)));
        LaunchMenu.Items.Add(new Separator());
        var up = MenuItem("Nach oben", "", () => MoveLaunchGroup(g, -1));
        up.IsEnabled = idx > 0;
        var down = MenuItem("Nach unten", "", () => MoveLaunchGroup(g, +1));
        down.IsEnabled = idx < S.LaunchGroups.Count - 1;
        LaunchMenu.Items.Add(up);
        LaunchMenu.Items.Add(down);
        LaunchMenu.Items.Add(new Separator());
        LaunchMenu.Items.Add(MenuItem("Löschen", "", () => DeleteLaunchGroup(g)));
    }

    private void LaunchList_DragOver(object sender, DragEventArgs e)
    {
        var lbi = FindParent<ListBoxItem>(e.OriginalSource as DependencyObject);
        bool ok = lbi is not null && e.Data.GetDataPresent(DataFormats.FileDrop);
        SetDropHighlight(ok ? lbi : null);
        e.Effects = ok ? DragDropEffects.Link | (e.AllowedEffects & DragDropEffects.Copy) : DragDropEffects.None;
        e.Handled = true;
    }

    private void LaunchList_Drop(object sender, DragEventArgs e)
    {
        SetDropHighlight(null);
        if (FindParent<ListBoxItem>(e.OriginalSource as DependencyObject)?.DataContext is LaunchGroupItem item &&
            e.Data.GetData(DataFormats.FileDrop) is string[] files)
            AddPathsToGroup(item.Group, files);
    }

    // ---------- Desktop-Verknüpfung ----------

    private void LaunchGroupShortcut_Click(object sender, RoutedEventArgs e)
    {
        if (CurrentGroup is { } g) CreateGroupShortcut(g.Group);
    }

    /// <summary>Legt "&lt;Name&gt; starten.lnk" auf den Desktop, die DeskCore.exe --launch "&lt;Name&gt;" aufruft.</summary>
    private void CreateGroupShortcut(LaunchGroup g)
    {
        try
        {
            var exe = Environment.ProcessPath!;
            var safe = string.Concat(g.Name.Split(Path.GetInvalidFileNameChars()));
            var link = Storage.UniquePath(Storage.UserDesktop, $"{safe} starten.lnk");
            Storage.MarkCreated(link); // nicht von der Auto-Sortierung einsammeln lassen
            dynamic shell = Activator.CreateInstance(Type.GetTypeFromProgID("WScript.Shell")!)!;
            dynamic l = shell.CreateShortcut(link);
            l.TargetPath = exe;
            l.Arguments = $"--launch \"{g.Name}\"";
            l.WorkingDirectory = Path.GetDirectoryName(exe);
            l.IconLocation = $"{exe},0";
            l.Description = $"Startet die DeskCore-Start-Gruppe „{g.Name}“";
            l.Save();
            ShowToast($"„{Path.GetFileNameWithoutExtension(link)}“ liegt jetzt auf dem Desktop", "");
        }
        catch (Exception ex) { Error("Verknüpfung fehlgeschlagen", ex.Message); }
    }
}