using System.Collections.Specialized;
using FluidExplorer.Helpers;
using FluidExplorer.Models;
using FluidExplorer.Navigation;
using FluidExplorer.Services;
using FluidExplorer.Services.Operations;
using FluidExplorer.Services.Shell;
using FluidExplorer.ViewModels;
using Microsoft.UI.Input;
using Microsoft.UI.Xaml;
using Microsoft.UI.Xaml.Controls;
using Microsoft.UI.Xaml.Controls.Primitives;
using Microsoft.UI.Xaml.Input;
using Microsoft.UI.Xaml.Media;
using Windows.ApplicationModel.DataTransfer;
using Windows.System;
using Windows.UI.Core;

namespace FluidExplorer.Views;

/// <summary>
/// 单个浏览窗格的视图：命令栏 + 地址栏 + 内容区 + 状态栏。
/// 所有交互都委托给 <see cref="ExplorerPaneViewModel"/>，视图本身不碰文件系统。
/// </summary>
public sealed partial class ExplorerPaneView : UserControl
{
    private static IReadOnlyList<string> _draggedPaths = [];

    public ExplorerPaneView()
    {
        InitializeComponent();
        Loaded += OnLoaded;
        Unloaded += OnUnloaded;
    }

    public static readonly DependencyProperty PaneProperty = DependencyProperty.Register(
        nameof(Pane),
        typeof(ExplorerPaneViewModel),
        typeof(ExplorerPaneView),
        new PropertyMetadata(null, OnPaneChanged));

    public ExplorerPaneViewModel? Pane
    {
        get => (ExplorerPaneViewModel?)GetValue(PaneProperty);
        set => SetValue(PaneProperty, value);
    }

    public MainViewModel Main => App.Services.Main;

    private static void OnPaneChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
    {
        var view = (ExplorerPaneView)d;
        if (e.OldValue is ExplorerPaneViewModel old)
        {
            old.PropertyChanged -= view.OnPanePropertyChanged;
            old.RenameRequested -= view.OnRenameRequested;
            old.ScrollIntoViewRequested -= view.OnScrollIntoViewRequested;
            old.FocusSearchRequested -= view.OnFocusSearchRequested;
            old.OpenInNewTabRequested -= view.OnOpenInNewTabRequested;
        }
        if (e.NewValue is ExplorerPaneViewModel pane)
        {
            pane.PropertyChanged += view.OnPanePropertyChanged;
            pane.RenameRequested += view.OnRenameRequested;
            pane.ScrollIntoViewRequested += view.OnScrollIntoViewRequested;
            pane.FocusSearchRequested += view.OnFocusSearchRequested;
            pane.OpenInNewTabRequested += view.OnOpenInNewTabRequested;
            view.ApplyIconSize();
        }
    }

    private void OnLoaded(object sender, RoutedEventArgs e)
    {
        ApplyIconSize();
        UpdateRecycleBinUi();
        ApplySidebarLayout();
        if (Pane is not null) SyncSidebarSelection(Pane.CurrentPath);
    }

    private void OnUnloaded(object sender, RoutedEventArgs e)
    {
        if (Pane is not null) Pane.PropertyChanged -= OnPanePropertyChanged;
    }

    private void OnPanePropertyChanged(object? sender, System.ComponentModel.PropertyChangedEventArgs e)
    {
        switch (e.PropertyName)
        {
            case nameof(ExplorerPaneViewModel.IconSize):
                ApplyIconSize();
                break;
            case nameof(ExplorerPaneViewModel.IsRecycleBin):
                UpdateRecycleBinUi();
                break;
            case nameof(ExplorerPaneViewModel.CurrentPath):
                if (Pane is not null) SyncSidebarSelection(Pane.CurrentPath);
                break;
            case nameof(ExplorerPaneViewModel.ShowSidebar):
                ApplySidebarLayout();
                break;
        }
    }

    private void UpdateRecycleBinUi()
    {
        RestoreButton.Visibility = Pane is { IsRecycleBin: true } ? Visibility.Visible : Visibility.Collapsed;
        HiddenToggle.IsChecked = Pane?.ShowHidden ?? false;
        ExtensionToggle.IsChecked = Main.ShowFileExtensions;
    }

    /// <summary>图标/磁贴尺寸跟随视图方式（网格用 ItemsWrapGrid 的单元格尺寸，避免布局跳动）。</summary>
    private void ApplyIconSize()
    {
        var pane = Pane;
        if (pane is null) return;

        foreach (var item in pane.Items) item.IconSize = Math.Min(pane.IconSize, 96);

        if (IconsGrid.ItemsPanelRoot is ItemsWrapGrid wrap)
        {
            wrap.ItemWidth = pane.TileWidth;
            wrap.ItemHeight = pane.TileHeight;
        }

        if (pane.IsIconsView && pane.Items.Count > 0)
        {
            // 视图切换后重新为可见项请求合适尺寸的缩略图
            foreach (var item in pane.Items.Take(120)) pane.Visuals.RequestThumbnail(item, pane.IconSize);
        }
    }

    // ── 导航窗格（侧边栏） ──────────────────────────────────────────────────
    private bool _sidebarCollapsed;

    private void OnToggleSidebarClick(object sender, RoutedEventArgs e)
    {
        _sidebarCollapsed = !_sidebarCollapsed;
        ApplySidebarLayout();
    }

    private void ApplySidebarLayout()
    {
        var show = Pane?.ShowSidebar != false && !_sidebarCollapsed;
        SidebarHost.Visibility = show ? Visibility.Visible : Visibility.Collapsed;
        SidebarColumn.Width = show ? new GridLength(242) : new GridLength(0);
    }

    private void OnSidebarItemInvoked(TreeView sender, TreeViewItemInvokedEventArgs args)
    {
        if (args.InvokedItem is SidebarNode node && Pane is not null)
            _ = Pane.NavigateAsync(node.Location);
    }

    private void OnSidebarExpanding(TreeView sender, TreeViewExpandingEventArgs args)
    {
        // 子项已在构建侧边栏时填充（驱动器数量少且读取廉价）
    }

    /// <summary>当前路径变化时高亮侧边栏对应节点（对齐资源管理器）。</summary>
    private void SyncSidebarSelection(string path)
    {
        if (string.IsNullOrEmpty(path)) return;
        foreach (var node in EnumerateNodes(SidebarTree.RootNodes))
        {
            if (node.Content is SidebarNode sidebarNode && sidebarNode.Contains(path))
            {
                SidebarTree.SelectedNode = node;
                return;
            }
        }
    }

    private static IEnumerable<TreeViewNode> EnumerateNodes(IEnumerable<TreeViewNode> nodes)
    {
        foreach (var node in nodes)
        {
            yield return node;
            foreach (var child in EnumerateNodes(node.Children)) yield return child;
        }
    }

    // ── 地址栏导航按钮 ──────────────────────────────────────────────────────
    private void OnBackClick(object sender, RoutedEventArgs e) => Pane?.BackCommand.Execute(null);

    private void OnForwardClick(object sender, RoutedEventArgs e) => Pane?.ForwardCommand.Execute(null);

    private void OnUpClick(object sender, RoutedEventArgs e) => Pane?.UpCommand.Execute(null);

    private void OnRefreshClick(object sender, RoutedEventArgs e) => Pane?.RefreshCommand.Execute(null);

    // ── 命令栏 ──────────────────────────────────────────────────────────────
    private void OnNewFolderClick(object sender, RoutedEventArgs e) => Pane?.NewFolderCommand.Execute(null);

    private void OnNewTextFileClick(object sender, RoutedEventArgs e)
    {
        if (Pane is null || Pane.Location.Kind is not (LocationKind.Folder or LocationKind.Drive)) return;
        try
        {
            var path = Path.Combine(Pane.CurrentPath, "新建文本文档.txt");
            var i = 2;
            while (File.Exists(path)) path = Path.Combine(Pane.CurrentPath, $"新建文本文档 ({i++}).txt");
            File.WriteAllText(path, string.Empty);
            _ = Pane.RefreshCommand.ExecuteAsync(null);
        }
        catch (Exception ex)
        {
            Pane.ReportError($"无法新建文件：{ex.Message}");
        }
    }

    private void OnNewTabClick(object sender, RoutedEventArgs e)
        => Main.AddTab(NavigationLocation.FromPath(Pane?.CurrentPath ?? string.Empty));

    private void OnCutClick(object sender, RoutedEventArgs e) => Pane?.CutSelectedCommand.Execute(SelectedItems());

    private void OnCopyClick(object sender, RoutedEventArgs e) => Pane?.CopySelectedCommand.Execute(SelectedItems());

    private void OnPasteClick(object sender, RoutedEventArgs e) => Pane?.PasteCommand.Execute(null);

    private void OnRenameClick(object sender, RoutedEventArgs e)
    {
        var item = SelectedItems().FirstOrDefault();
        if (item is not null) Pane?.StartRenameCommand.Execute(item);
    }

    private void OnDeleteClick(object sender, RoutedEventArgs e)
    {
        var items = SelectedItems();
        if (items.Count == 0) return;
        var shift = IsKeyDown(VirtualKey.Shift);
        if (shift) Pane?.PermanentDeleteSelectedCommand.Execute(items);
        else Pane?.DeleteSelectedCommand.Execute(items);
    }

    private void OnUndoClick(object sender, RoutedEventArgs e) => Main.UndoCommand.Execute(null);

    private void OnRestoreClick(object sender, RoutedEventArgs e) => Pane?.RestoreSelectedCommand.Execute(SelectedItems());

    private void OnSortClick(object sender, RoutedEventArgs e)
    {
        if (sender is FrameworkElement { Tag: string tag } && Enum.TryParse<SortColumn>(tag, out var column))
            Pane?.SortByCommand.Execute(column);
    }

    private void OnSortDirectionClick(object sender, RoutedEventArgs e)
    {
        if (Pane is null || sender is not FrameworkElement { Tag: string tag }) return;
        Pane.Sort = Pane.Sort with { Direction = tag == "Descending" ? SortDirection.Descending : SortDirection.Ascending };
        Pane.ApplySortAndRefresh();
    }

    private void OnViewModeClick(object sender, RoutedEventArgs e)
    {
        if (sender is FrameworkElement { Tag: string tag }) Pane?.SetViewModeCommand.Execute(tag);
    }

    private void OnCycleViewClick(object sender, RoutedEventArgs e) => Pane?.CycleViewModeCommand.Execute(null);

    private void OnToggleDualPaneClick(object sender, RoutedEventArgs e) => Main.ToggleDualPaneCommand.Execute(null);

    private void OnToggleHiddenClick(object sender, RoutedEventArgs e) => Pane?.ToggleHiddenCommand.Execute(null);

    private void OnToggleExtensionClick(object sender, RoutedEventArgs e) => Main.ShowFileExtensions = !Main.ShowFileExtensions;

    private async void OnShellContextMenuClick(object sender, RoutedEventArgs e)
    {
        var paths = SelectedItems().Select(i => i.FullPath).ToList();
        if (paths.Count == 0)
        {
            var dir = Pane?.CurrentPath;
            if (!string.IsNullOrEmpty(dir) && Directory.Exists(dir)) paths.Add(dir);
        }
        if (paths.Count > 0) await ShowShellContextMenuAsync(paths);
    }

    private async Task ShowShellContextMenuAsync(IReadOnlyList<string> paths)
    {
        if (paths.Count == 0) return;
        var hwnd = WinRT.Interop.WindowNative.GetWindowHandle(App.MainWindowInstance);
        var anchor = DetailsList.TransformToVisual(null).TransformPoint(new Windows.Foundation.Point(48, 48));
        var scale = XamlRoot?.RasterizationScale ?? 1.0;
        var origin = App.MainWindowInstance.AppWindow.Position;
        var screen = new Windows.Graphics.PointInt32(
            origin.X + (int)(anchor.X * scale),
            origin.Y + (int)(anchor.Y * scale));

        await ShellContextMenu.ShowAsync(hwnd, paths, screen);
    }

    // ── 地址栏 ──────────────────────────────────────────────────────────────
    private async void OnBreadcrumbClicked(BreadcrumbBar sender, BreadcrumbBarItemClickedEventArgs args)
    {
        if (args.Item is BreadcrumbSegment segment && Pane is not null)
            await Pane.NavigateAsync(new NavigationLocation(
                segment.IsDriveRoot ? LocationKind.Drive : LocationKind.Folder,
                segment.Path,
                segment.DisplayName,
                "\uE8B7"));
    }

    private void OnAddressEditorKeyDown(object sender, KeyRoutedEventArgs e)
    {
        if (e.Key == VirtualKey.Enter)
        {
            e.Handled = true;
            var text = AddressEditor.Text;
            AddressEditor.Visibility = Visibility.Collapsed;
            AddressBreadcrumb.Visibility = Visibility.Visible;
            _ = Pane?.NavigatePathCommand.ExecuteAsync(text);
        }
        else if (e.Key == VirtualKey.Escape)
        {
            e.Handled = true;
            AddressEditor.Visibility = Visibility.Collapsed;
            AddressBreadcrumb.Visibility = Visibility.Visible;
        }
    }

    private void OnAddressEditorLostFocus(object sender, RoutedEventArgs e)
    {
        AddressEditor.Visibility = Visibility.Collapsed;
        AddressBreadcrumb.Visibility = Visibility.Visible;
    }

    /// <summary>Ctrl+L / F4：切换到可编辑的地址输入（资源管理器行为）。</summary>
    private void BeginAddressEdit()
    {
        AddressEditor.Text = Pane?.CurrentPath ?? string.Empty;
        AddressEditor.Visibility = Visibility.Visible;
        AddressBreadcrumb.Visibility = Visibility.Collapsed;
        AddressEditor.Focus(FocusState.Programmatic);
        AddressEditor.SelectAll();
    }

    // ── 搜索 ────────────────────────────────────────────────────────────────
    private async void OnSearchTextChanged(AutoSuggestBox sender, AutoSuggestBoxTextChangedEventArgs args)
    {
        // SuggestionChosen 是我们自己回填的，不重复搜索；其余变化（含程序化写入、粘贴）都要触发
        if (args.Reason == AutoSuggestionBoxTextChangeReason.SuggestionChosen) return;
        if (Pane is null) return;
        if (!Main.Settings.SearchAsYouType && args.Reason == AutoSuggestionBoxTextChangeReason.UserInput)
        {
            // 关闭"键入即搜"时只在回车/提交时搜索
            return;
        }
        await Pane.SearchAsync(sender.Text);

        // 顶部建议：直接把最快命中的前 8 条塞进下拉框（Everything 式即时反馈）
        var suggestions = Pane.SearchResults.Take(8).Select(r => r.FullPath).ToList();
        sender.ItemsSource = suggestions;
    }

    private async void OnSearchQuerySubmitted(AutoSuggestBox sender, AutoSuggestBoxQuerySubmittedEventArgs args)
    {
        if (Pane is null) return;
        await Pane.SearchAsync(args.QueryText);
    }

    private async void OnSearchSuggestionChosen(AutoSuggestBox sender, AutoSuggestBoxSuggestionChosenEventArgs args)
    {
        if (Pane is null || args.SelectedItem is not string path) return;
        sender.Text = path;
        await Pane.SearchAsync(path);
    }

    private void OnDismissErrorClick(InfoBar sender, object args) => Pane?.DismissError();

    // ── 列表交互 ────────────────────────────────────────────────────────────
    private List<ExplorerItem> SelectedItems()
        => Pane is null
            ? []
            : (Pane.IsDetailsView || Pane.IsIconsView
                ? (Pane.IsDetailsView ? DetailsList.SelectedItems : IconsGrid.SelectedItems).OfType<ExplorerItem>().ToList()
                : []);

    private void OnListSelectionChanged(object sender, SelectionChangedEventArgs e)
    {
        if (Pane is null) return;
        var listView = sender as ListViewBase;
        var selected = listView?.SelectedItems.OfType<ExplorerItem>().ToList() ?? [];
        Pane.OnSelectionChanged(selected);
    }

    private void OnDetailsContainerChanging(ListViewBase sender, ContainerContentChangingEventArgs args)
    {
        if (args.InRecycleQueue || args.Item is not ExplorerItem item) return;
        Pane?.Visuals.RequestIcon(item, 16);
    }

    private void OnIconsContainerChanging(ListViewBase sender, ContainerContentChangingEventArgs args)
    {
        if (args.InRecycleQueue || args.Item is not ExplorerItem item || Pane is null) return;
        item.IconSize = Math.Min(Pane.IconSize, 96);
        Pane.Visuals.RequestThumbnail(item, Pane.IconSize);
    }

    private void OnSearchContainerChanging(ListViewBase sender, ContainerContentChangingEventArgs args)
    {
        if (args.InRecycleQueue || args.Item is not SearchResultItem item) return;
        Pane?.Visuals.RequestIcon(item, 16);
    }

    private void OnItemDoubleTapped(object sender, DoubleTappedRoutedEventArgs e)
    {
        if (Pane is null) return;
        var item = ResolveItemAt(e.OriginalSource as DependencyObject);
        if (item is not null) _ = Pane.OpenItemAsync(item);
    }

    private void OnSearchResultDoubleTapped(object sender, DoubleTappedRoutedEventArgs e)
    {
        var item = ResolveSearchItemAt(e.OriginalSource as DependencyObject);
        if (item is not null) _ = Pane!.OpenSearchResultAsync(item);
    }

    private static ExplorerItem? ResolveItemAt(DependencyObject? source)
    {
        while (source is not null)
        {
            if (source is FrameworkElement { DataContext: ExplorerItem item }) return item;
            source = VisualTreeHelper.GetParent(source);
        }
        return null;
    }

    private static SearchResultItem? ResolveSearchItemAt(DependencyObject? source)
    {
        while (source is not null)
        {
            if (source is FrameworkElement { DataContext: SearchResultItem item }) return item;
            source = VisualTreeHelper.GetParent(source);
        }
        return null;
    }

    private void OnListKeyDown(object sender, KeyRoutedEventArgs e)
    {
        if (Pane is null) return;
        var ctrl = IsKeyDown(VirtualKey.Control);
        var shift = IsKeyDown(VirtualKey.Shift);

        switch (e.Key)
        {
            case VirtualKey.Enter when !ctrl:
                e.Handled = true;
                Pane.OpenSelectedCommand.Execute(SelectedItems());
                break;
            case VirtualKey.F2:
                e.Handled = true;
                Pane.StartRenameCommand.Execute(SelectedItems().FirstOrDefault());
                break;
            case VirtualKey.Back when !ctrl:
                e.Handled = true;
                Pane.UpCommand.Execute(null);
                break;
            case VirtualKey.Delete:
                e.Handled = true;
                OnDeleteClick(sender, e);
                break;
            case VirtualKey.F5:
                e.Handled = true;
                Pane.RefreshCommand.Execute(null);
                break;
            case VirtualKey.C when ctrl && shift:
                e.Handled = true;
                Pane.CopyPathSelectedCommand.Execute(SelectedItems());
                break;
            case VirtualKey.C when ctrl:
                e.Handled = true;
                Pane.CopySelectedCommand.Execute(SelectedItems());
                break;
            case VirtualKey.X when ctrl:
                e.Handled = true;
                Pane.CutSelectedCommand.Execute(SelectedItems());
                break;
            case VirtualKey.V when ctrl:
                e.Handled = true;
                Pane.PasteCommand.Execute(null);
                break;
            case VirtualKey.N when ctrl && shift:
                e.Handled = true;
                Pane.NewFolderCommand.Execute(null);
                break;
            case VirtualKey.L when ctrl:
                e.Handled = true;
                BeginAddressEdit();
                break;
            case VirtualKey.Up when IsKeyDown(VirtualKey.Menu):
                e.Handled = true;
                Pane.UpCommand.Execute(null);
                break;
            case VirtualKey.Left when IsKeyDown(VirtualKey.Menu):
                e.Handled = true;
                Pane.BackCommand.Execute(null);
                break;
            case VirtualKey.Right when IsKeyDown(VirtualKey.Menu):
                e.Handled = true;
                Pane.ForwardCommand.Execute(null);
                break;
        }
    }

    private static bool IsKeyDown(VirtualKey key)
        => InputKeyboardSource.GetKeyStateForCurrentThread(key).HasFlag(CoreVirtualKeyStates.Down);

    // ── 重命名输入框 ────────────────────────────────────────────────────────
    private void OnRenameRequested(object? sender, ExplorerItem item)
    {
        DispatcherQueue.TryEnqueue(() => FocusRenameBox(item));
    }

    private void FocusRenameBox(ExplorerItem item)
    {
        var host = Pane?.IsDetailsView == true ? (DependencyObject)DetailsList : IconsGrid;
        var container = host is ListViewBase list
            ? list.ContainerFromItem(item) as DependencyObject
            : null;
        if (container is null) return;
        if (FindRenameBox(container) is { } box)
        {
            box.Focus(FocusState.Programmatic);
            box.SelectAll();
        }
    }

    private static TextBox? FindRenameBox(DependencyObject root)
    {
        if (root is TextBox { Tag: "rename" } box) return box;
        var count = VisualTreeHelper.GetChildrenCount(root);
        for (var i = 0; i < count; i++)
        {
            var child = VisualTreeHelper.GetChild(root, i);
            if (FindRenameBox(child) is { } found) return found;
        }
        return null;
    }

    private void OnRenameBoxKeyDown(object sender, KeyRoutedEventArgs e)
    {
        if (sender is not TextBox box || box.DataContext is not ExplorerItem item) return;
        if (e.Key == VirtualKey.Enter)
        {
            e.Handled = true;
            Pane?.CommitRenameCommand.Execute(item);
        }
        else if (e.Key == VirtualKey.Escape)
        {
            e.Handled = true;
            Pane?.CancelRenameCommand.Execute(item);
        }
    }

    private void OnRenameBoxLostFocus(object sender, RoutedEventArgs e)
    {
        if (sender is TextBox { DataContext: ExplorerItem item } && item.IsRenaming)
            Pane?.CommitRenameCommand.Execute(item);
    }

    private void OnScrollIntoViewRequested(object? sender, ExplorerItem item)
    {
        if (Pane?.IsDetailsView == true) DetailsList.ScrollIntoView(item);
        else IconsGrid.ScrollIntoView(item);
    }

    private void OnFocusSearchRequested(object? sender, EventArgs e)
    {
        SearchBox.Focus(FocusState.Programmatic);
    }

    private void OnOpenInNewTabRequested(object? sender, NavigationLocation location)
    {
        Main.AddTab(location);
    }

    // ── 右键菜单（应用内 + 系统原版） ───────────────────────────────────────
    private void OnContextRequested(UIElement sender, ContextRequestedEventArgs args)
    {
        if (Pane is null || sender is not FrameworkElement target) return;
        var selected = SelectedItems();
        var flyout = BuildContextFlyout(selected);
        if (args.TryGetPosition(sender, out var position)) flyout.ShowAt(target, new FlyoutShowOptions { Position = position });
        else flyout.ShowAt(target);
        args.Handled = true;
    }

    private void OnSearchResultContextRequested(UIElement sender, ContextRequestedEventArgs args)
    {
        if (sender is not FrameworkElement target) return;
        var flyout = new MenuFlyout();
        var openItem = new MenuFlyoutItem { Text = "打开" };
        openItem.Click += (_, _) => _ = Pane?.OpenSearchResultCommand.ExecuteAsync(SingleSearchResult(sender));
        var openFolder = new MenuFlyoutItem { Text = "打开所在文件夹" };
        openFolder.Click += (_, _) => _ = Pane?.OpenSearchResultFolderCommand.ExecuteAsync(SingleSearchResult(sender));
        var copyPath = new MenuFlyoutItem { Text = "复制完整路径" };
        copyPath.Click += (_, _) =>
        {
            var item = SingleSearchResult(sender);
            if (item is null) return;
            var package = new DataPackage();
            package.SetText(item.FullPath);
            Clipboard.SetContent(package);
        };
        flyout.Items.Add(openItem);
        flyout.Items.Add(openFolder);
        flyout.Items.Add(copyPath);
        if (args.TryGetPosition(sender, out var position)) flyout.ShowAt(target, new FlyoutShowOptions { Position = position });
        else flyout.ShowAt(target);
        args.Handled = true;

        SearchResultItem? SingleSearchResult(UIElement element)
            => (element as ListViewBase)?.SelectedItems.OfType<SearchResultItem>().FirstOrDefault();
    }

    private MenuFlyout BuildContextFlyout(IReadOnlyList<ExplorerItem> selection)
    {
        var flyout = new MenuFlyout();

        if (selection.Count > 0)
        {
            var open = new MenuFlyoutItem { Text = "打开", Icon = new FontIcon { Glyph = "\uE8E5" } };
            open.Click += (_, _) => Pane?.OpenSelectedCommand.Execute(selection);
            flyout.Items.Add(open);

            if (selection.Count == 1 && !selection[0].IsDirectory)
            {
                var openWith = new MenuFlyoutItem { Text = "打开方式" };
                openWith.Click += (_, _) => Pane?.OpenWithSelectedCommand.Execute(selection);
                flyout.Items.Add(openWith);
            }

            if (selection.Count == 1 && selection[0].IsDirectory)
            {
                var newTab = new MenuFlyoutItem { Text = "在新标签页中打开" };
                newTab.Click += (_, _) => Pane?.OpenInNewTabCommand.Execute(selection[0]);
                flyout.Items.Add(newTab);
            }

            flyout.Items.Add(new MenuFlyoutSeparator());

            var cut = new MenuFlyoutItem { Text = "剪切", Icon = new FontIcon { Glyph = "\uE8C6" } };
            cut.Click += (_, _) => Pane?.CutSelectedCommand.Execute(selection);
            var copy = new MenuFlyoutItem { Text = "复制", Icon = new FontIcon { Glyph = "\uE8C8" } };
            copy.Click += (_, _) => Pane?.CopySelectedCommand.Execute(selection);
            var copyPath = new MenuFlyoutItem { Text = "复制完整路径" };
            copyPath.Click += (_, _) => Pane?.CopyPathSelectedCommand.Execute(selection);
            var rename = new MenuFlyoutItem { Text = "重命名", Icon = new FontIcon { Glyph = "\uE8AC" } };
            rename.Click += (_, _) => Pane?.StartRenameCommand.Execute(selection[0]);
            var delete = new MenuFlyoutItem { Text = "删除", Icon = new FontIcon { Glyph = "\uE74D" } };
            delete.Click += (_, _) => Pane?.DeleteSelectedCommand.Execute(selection);

            flyout.Items.Add(cut);
            flyout.Items.Add(copy);
            flyout.Items.Add(copyPath);
            flyout.Items.Add(rename);
            flyout.Items.Add(delete);

            if (Pane is { IsRecycleBin: true })
            {
                var restore = new MenuFlyoutItem { Text = "还原" };
                restore.Click += (_, _) => Pane?.RestoreSelectedCommand.Execute(selection);
                flyout.Items.Add(restore);
            }

            flyout.Items.Add(new MenuFlyoutSeparator());

            var properties = new MenuFlyoutItem { Text = "属性", Icon = new FontIcon { Glyph = "\uE946" } };
            properties.Click += (_, _) => Pane?.ShowPropertiesSelectedCommand.Execute(selection);
            var reveal = new MenuFlyoutItem { Text = "在资源管理器中显示" };
            reveal.Click += (_, _) => Pane?.RevealSelectedCommand.Execute(selection);
            flyout.Items.Add(properties);
            flyout.Items.Add(reveal);
        }
        else
        {
            var refresh = new MenuFlyoutItem { Text = "刷新", Icon = new FontIcon { Glyph = "\uE72C" } };
            refresh.Click += (_, _) => Pane?.RefreshCommand.Execute(null);
            var newFolder = new MenuFlyoutItem { Text = "新建文件夹", Icon = new FontIcon { Glyph = "\uE8B7" } };
            newFolder.Click += (_, _) => Pane?.NewFolderCommand.Execute(null);
            var paste = new MenuFlyoutItem { Text = "粘贴", Icon = new FontIcon { Glyph = "\uE77F" } };
            paste.Click += (_, _) => Pane?.PasteCommand.Execute(null);
            flyout.Items.Add(refresh);
            flyout.Items.Add(newFolder);
            flyout.Items.Add(paste);
        }

        flyout.Items.Add(new MenuFlyoutSeparator());
        var showMore = new MenuFlyoutItem { Text = "显示更多选项（系统菜单）" };
        showMore.Click += async (_, _) => await ShowShellContextMenuAsync(
            selection.Count > 0
                ? selection.Select(i => i.FullPath).ToList()
                : (Pane?.CurrentPath is { Length: > 0 } p && Directory.Exists(p) ? [p] : []));
        flyout.Items.Add(showMore);

        return flyout;
    }

    // ── 拖放 ────────────────────────────────────────────────────────────────
    private void OnDragItemsStarting(object sender, DragItemsStartingEventArgs e)
    {
        var items = e.Items.OfType<ExplorerItem>().ToList();
        var paths = items.Select(i => i.FullPath).ToList();
        _draggedPaths = paths;
        e.Data.RequestedOperation = DataPackageOperation.Copy | DataPackageOperation.Move;

        e.Data.SetDataProvider(StandardDataFormats.StorageItems, async request =>
        {
            var deferral = request.GetDeferral();
            try
            {
                var storageItems = new List<Windows.Storage.IStorageItem>();
                foreach (var path in paths)
                {
                    try
                    {
                        if (Directory.Exists(path))
                            storageItems.Add(await Windows.Storage.StorageFolder.GetFolderFromPathAsync(path));
                        else if (File.Exists(path))
                            storageItems.Add(await Windows.Storage.StorageFile.GetFileFromPathAsync(path));
                    }
                    catch
                    {
                        // 单个项目不可用时跳过，不阻断整次拖放
                    }
                }
                request.SetData(storageItems);
            }
            finally
            {
                deferral.Complete();
            }
        });
    }

    private void OnDragOver(object sender, DragEventArgs e)
    {
        if (!e.DataView.Contains(StandardDataFormats.StorageItems)) return;
        var copy = IsKeyDown(VirtualKey.Control);
        e.AcceptedOperation = copy ? DataPackageOperation.Copy : DataPackageOperation.Move;
        e.DragUIOverride.Caption = copy ? $"复制到“{Pane?.Title}”" : $"移动到“{Pane?.Title}”";
        e.DragUIOverride.IsCaptionVisible = true;
    }

    private async void OnDrop(object sender, DragEventArgs e)
    {
        if (Pane is null || !e.DataView.Contains(StandardDataFormats.StorageItems)) return;
        var deferral = e.GetDeferral();
        try
        {
            var target = ResolveDropTarget(e);
            var pathCopy = IsKeyDown(VirtualKey.Control);

            // 优先使用应用内拖动的路径（避免 StorageItem 往返），否则从数据包读取
            var paths = _draggedPaths.Count > 0
                ? _draggedPaths.ToList()
                : (await e.DataView.GetStorageItemsAsync()).Select(i => i.Path).ToList();

            await Pane.DropIntoAsync(paths, target, pathCopy);
        }
        catch (Exception ex)
        {
            Pane.ReportError($"拖放失败：{ex.Message}");
        }
        finally
        {
            deferral.Complete();
        }
    }

    /// <summary>拖到文件夹行上 → 放进该文件夹；拖到空白处 → 放进当前文件夹。</summary>
    private string ResolveDropTarget(DragEventArgs e)
    {
        var dropPoint = e.GetPosition(DetailsList);
        var elements = VisualTreeHelper.FindElementsInHostCoordinates(dropPoint, DetailsList);
        foreach (var element in elements)
        {
            if (element is FrameworkElement { DataContext: ExplorerItem { IsDirectory: true } folder })
                return folder.FullPath;
        }
        return Pane?.CurrentPath ?? string.Empty;
    }

    // ── 状态栏 ──────────────────────────────────────────────────────────────
    private void OnIndexChipTapped(object sender, TappedRoutedEventArgs e)
    {
        if (Main.IndexNeedsElevation) Main.RestartElevatedCommand.Execute(null);
        else Main.BuildIndexCommand.Execute(null);
    }

    private void OnOpenQueueClick(object sender, RoutedEventArgs e)
    {
        Main.IsQueueExpanded = true;
        App.MainWindowInstance.ShowOperationQueue();
    }

    private async void OnOpenSettingsClick(object sender, RoutedEventArgs e)
    {
        var dialog = new SettingsDialog(Main) { XamlRoot = XamlRoot };
        await dialog.ShowAsync();
    }
}