import 'package:file_picker/file_picker.dart';
import 'package:file_saver/file_saver.dart';
import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:intl/intl.dart';
import 'package:material_symbols_icons/symbols.dart';
import 'package:path/path.dart' as p;
import 'package:path_provider/path_provider.dart';
import 'package:provider/provider.dart';
import 'package:share_plus/share_plus.dart';
import '../models/nextcloud_item.dart';
import '../models/selection_action.dart';
import '../providers/server_provider.dart';
import '../widgets/breadcrumbs.dart';
import '../widgets/details/details_sheet.dart';
import '../widgets/more_tabs_button.dart';
import '../widgets/profile_avatar_button.dart';
import '../widgets/segmented_icon_toggle.dart';
import '../widgets/selectable_thumbnail.dart';
import '../widgets/share_sheet.dart';
import '../widgets/sort_menu_button.dart';
import '../widgets/sticky_header_delegate.dart';
import '../widgets/swipeable_item.dart';
import '../widgets/synced_header_scaffold.dart';
import 'file_viewer_screen.dart';

class FilesView extends StatefulWidget {
  final ScrollController scrollController;

  const FilesView({super.key, required this.scrollController});

  @override
  State<FilesView> createState() => _FilesViewState();
}

IconData _getItemIcon(NextcloudItemType type) {
  switch (type) {
    case NextcloudItemType.folder:
      return Icons.folder_rounded;
    case NextcloudItemType.image:
      return Icons.image_rounded;
    case NextcloudItemType.video:
      return Icons.movie_rounded;
    case NextcloudItemType.audio:
      return Icons.audiotrack_rounded;
    case NextcloudItemType.document:
      return Icons.description_rounded;
    case NextcloudItemType.archive:
      return Icons.folder_zip_rounded;
    case NextcloudItemType.file:
      return Icons.insert_drive_file_rounded;
  }
}

Color _getIconColor(BuildContext context, NextcloudItemType type) {
  final colorScheme = Theme.of(context).colorScheme;
  switch (type) {
    case NextcloudItemType.folder:
      return colorScheme.primary;
    case NextcloudItemType.image:
      return Colors.amber.shade700;
    case NextcloudItemType.video:
      return Colors.deepOrange.shade600;
    case NextcloudItemType.audio:
      return Colors.purple.shade600;
    case NextcloudItemType.document:
      return Colors.blue.shade700;
    case NextcloudItemType.archive:
      return Colors.teal.shade700;
    case NextcloudItemType.file:
      return colorScheme.outline;
  }
}

/// A file/folder's icon badge — for images and videos this shows an actual
/// thumbnail (falling back to the plain icon on error or if there's no
/// preview URL yet), matching the real-content treatment already used in
/// the Photos tab.
class _ItemThumbnail extends StatelessWidget {
  final NextcloudItem item;
  final ServerProvider provider;
  final double size;
  final double borderRadius;
  final double iconSize;

  const _ItemThumbnail({
    required this.item,
    required this.provider,
    required this.size,
    required this.borderRadius,
    required this.iconSize,
  });

  @override
  Widget build(BuildContext context) {
    final iconColor = _getIconColor(context, item.type);
    final isMedia =
        item.type == NextcloudItemType.image ||
        item.type == NextcloudItemType.video;
    // Decode straight to the size this thumbnail is actually painted at —
    // the server hands back a 500x500 preview regardless, and decoding that
    // in full for a ~40dp tile (times however many are on screen while
    // scrolling) is a real source of jank.
    final cachePixels = (size * MediaQuery.of(context).devicePixelRatio)
        .round();

    return Container(
      width: size,
      height: size,
      clipBehavior: Clip.antiAlias,
      decoration: BoxDecoration(
        color: iconColor.withValues(alpha: 0.12),
        borderRadius: BorderRadius.circular(borderRadius),
      ),
      child: isMedia && item.previewUrl != null
          ? Stack(
              fit: StackFit.expand,
              children: [
                Image.network(
                  item.previewUrl!,
                  headers: provider.service?.authHeaders,
                  fit: BoxFit.cover,
                  cacheWidth: cachePixels,
                  cacheHeight: cachePixels,
                  filterQuality: FilterQuality.low,
                  gaplessPlayback: true,
                  loadingBuilder: (context, child, progress) {
                    if (progress == null) return child;
                    return Center(
                      child: Icon(
                        _getItemIcon(item.type),
                        color: iconColor,
                        size: iconSize,
                      ),
                    );
                  },
                  errorBuilder: (context, error, stack) => Center(
                    child: Icon(
                      _getItemIcon(item.type),
                      color: iconColor,
                      size: iconSize,
                    ),
                  ),
                ),
                if (item.type == NextcloudItemType.video)
                  const Center(
                    child: Icon(
                      Icons.play_circle_fill_rounded,
                      color: Colors.white,
                      size: 18,
                    ),
                  ),
              ],
            )
          : Center(
              child: Icon(
                _getItemIcon(item.type),
                color: iconColor,
                size: iconSize,
              ),
            ),
    );
  }
}

class _FilesViewState extends State<FilesView> {
  final Set<String> _selectedIds = {};

  bool get _isSelecting => _selectedIds.isNotEmpty;

  void _toggleSelection(NextcloudItem item) {
    HapticFeedback.selectionClick();
    setState(() {
      if (!_selectedIds.remove(item.id)) _selectedIds.add(item.id);
    });
  }

  void _clearSelection() {
    setState(_selectedIds.clear);
  }

  /// The bulk actions shown in the sticky selection toolbar for the
  /// currently-selected items.
  List<SelectionAction> _buildSelectionActions(
    ServerProvider provider,
    List<NextcloudItem> selected,
  ) {
    return [
      SelectionAction(
        icon: selected.every((i) => i.isFavorite)
            ? Icons.favorite_rounded
            : Icons.favorite_border_rounded,
        label: selected.every((i) => i.isFavorite)
            ? 'Remove from favorites'
            : 'Favorite',
        color: Colors.red.shade400,
        onTap: () => _favoriteSelected(provider, selected),
      ),
      SelectionAction(
        icon: Icons.share_rounded,
        label: 'Share',
        onTap: () => selected.length == 1
            ? ShareSheet.show(context, selected.single)
            : _shareSelected(context, provider, selected),
      ),
      SelectionAction(
        icon: Icons.download_rounded,
        label: 'Download',
        onTap: () => _downloadSelected(context, provider, selected),
      ),
      SelectionAction(
        icon: Icons.delete_outline_rounded,
        label: 'Delete',
        color: Theme.of(context).colorScheme.error,
        onTap: () => _confirmDeleteSelected(context, provider, selected),
      ),
      if (selected.length == 1)
        SelectionAction(
          icon: Icons.drive_file_rename_outline_rounded,
          label: 'Rename',
          onTap: () => _renameItem(provider, selected.single),
        ),
      if (selected.length == 1)
        SelectionAction(
          icon: Icons.info_outline_rounded,
          label: 'Details',
          onTap: () => DetailsSheet.show(context, selected.single),
        ),
    ];
  }

  Future<void> _renameItem(ServerProvider provider, NextcloudItem item) async {
    final controller = TextEditingController(text: item.name);
    final newName = await showDialog<String>(
      context: context,
      builder: (dialogContext) {
        return AlertDialog(
          title: const Text('Rename'),
          content: TextField(
            controller: controller,
            autofocus: true,
            decoration: const InputDecoration(labelText: 'Name'),
            onSubmitted: (value) => Navigator.pop(dialogContext, value.trim()),
          ),
          actions: [
            TextButton(
              onPressed: () => Navigator.pop(dialogContext),
              child: const Text('Cancel'),
            ),
            FilledButton(
              onPressed: () =>
                  Navigator.pop(dialogContext, controller.text.trim()),
              child: const Text('Rename'),
            ),
          ],
        );
      },
    );
    // Not disposed here: `showDialog`'s Future resolves as soon as the pop
    // is initiated, while the dialog (and this controller's TextField)
    // is still mounted and mid-exit-transition - disposing immediately
    // crashes with a "still has listeners" assertion. It's a plain,
    // short-lived controller with no ticker/stream to leak, so letting it
    // get garbage-collected once the transition finishes is the safe call.
    if (newName == null || newName.isEmpty || newName == item.name) return;
    if (!mounted) return;

    final messenger = ScaffoldMessenger.of(context);
    final success = await provider.renameItem(item, newName);
    _clearSelection();
    messenger.showSnackBar(
      SnackBar(
        content: Text(
          success ? 'Renamed to $newName' : 'Failed to rename ${item.name}',
        ),
        behavior: SnackBarBehavior.floating,
      ),
    );
  }

  Future<void> _shareSelected(
    BuildContext context,
    ServerProvider provider,
    List<NextcloudItem> items,
  ) async {
    final messenger = ScaffoldMessenger.of(context);
    messenger.showSnackBar(
      const SnackBar(
        content: Text('Creating share link(s)…'),
        behavior: SnackBarBehavior.floating,
      ),
    );

    final lines = <String>[];
    for (final item in items) {
      final link = await provider.createShareLink(item);
      if (link != null) {
        lines.add(items.length > 1 ? '${item.name}: $link' : link);
      }
    }

    if (!mounted) return;
    messenger.hideCurrentSnackBar();
    _clearSelection();
    if (lines.isEmpty) {
      messenger.showSnackBar(
        const SnackBar(
          content: Text('Could not create share link(s)'),
          behavior: SnackBarBehavior.floating,
        ),
      );
      return;
    }

    try {
      await SharePlus.instance.share(ShareParams(text: lines.join('\n')));
    } catch (_) {
      if (!mounted) return;
      messenger.showSnackBar(
        const SnackBar(
          content: Text('Could not open the share sheet'),
          behavior: SnackBarBehavior.floating,
        ),
      );
    }
  }

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);
    final colorScheme = theme.colorScheme;
    final provider = context.watch<ServerProvider>();

    final hasBreadcrumbs = provider.pathStack.length > 1;
    final selectedItems = provider.items
        .where((i) => _selectedIds.contains(i.id))
        .toList();

    final controlsRow = Padding(
      // 16, not 20 - matches the SliverAppBar toolbar's own default
      // horizontal content inset when it's selecting, so the two rows'
      // content lines up instead of the controls row looking shifted in.
      padding: const EdgeInsets.fromLTRB(16, 16, 16, 12),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          SizedBox(
            height: 44,
            child: Row(
              children: [
                IconButton(
                  icon: Icon(
                    provider.filesSortAscending
                        ? Icons.arrow_upward_rounded
                        : Icons.arrow_downward_rounded,
                    size: 20,
                  ),
                  visualDensity: VisualDensity.compact,
                  tooltip: provider.filesSortAscending
                      ? 'Ascending'
                      : 'Descending',
                  onPressed: provider.toggleFilesSortOrder,
                ),
                Expanded(
                  child: SortMenuButton(
                    field: provider.filesSortField,
                    onChanged: provider.setFilesSortField,
                  ),
                ),
                ToggleIconButton(
                  icon: provider.showFavoritesOnlyFiles
                      ? Icons.favorite_rounded
                      : Icons.favorite_border_rounded,
                  isSelected: provider.showFavoritesOnlyFiles,
                  onTap: provider.toggleFavoritesFilterFiles,
                  tooltip: 'Favorites only',
                ),
                const SizedBox(width: 4),
                ToggleIconButton(
                  icon: provider.showHiddenFiles
                      ? Icons.visibility_rounded
                      : Icons.visibility_off_rounded,
                  isSelected: provider.showHiddenFiles,
                  onTap: () => provider.toggleShowHiddenFiles(),
                  tooltip: 'Show hidden files',
                ),
                const SizedBox(width: 4),
                SegmentedIconGroup(
                  children: [
                    ToggleIconButton(
                      icon: Symbols.circles_rounded,
                      isSelected: provider.storageScope == StorageScope.cloud,
                      onTap: () => provider.setStorageScope(StorageScope.cloud),
                      tooltip: 'Cloud storage',
                    ),
                    ToggleIconButton(
                      icon: Symbols.hard_drive_rounded,
                      isSelected:
                          provider.storageScope == StorageScope.external,
                      onTap: () =>
                          provider.setStorageScope(StorageScope.external),
                      tooltip: 'External storage',
                    ),
                  ],
                ),
                const SizedBox(width: 8),
                SegmentedIconGroup(
                  children: [
                    ToggleIconButton(
                      icon: Icons.view_list_rounded,
                      isSelected: !provider.isGridView,
                      onTap: () => provider.setGridView(false),
                      tooltip: 'List view',
                    ),
                    ToggleIconButton(
                      icon: Icons.grid_view_rounded,
                      isSelected: provider.isGridView,
                      onTap: () => provider.setGridView(true),
                      tooltip: 'Grid view',
                    ),
                  ],
                ),
              ],
            ),
          ),
          if (hasBreadcrumbs) ...[
            const SizedBox(height: 10),
            SizedBox(
              height: 32,
              child: Breadcrumbs(
                pathStack: provider.pathStack,
                onTap: (index) => provider.navigateToPathIndex(index),
              ),
            ),
          ],
        ],
      ),
    );

    final List<Widget> contentSlivers = [
      // Sticky while browsing; once selecting, the toolbar below takes over
      // the pinned slot and this is free to scroll away.
      SliverPersistentHeader(
        pinned: !_isSelecting,
        delegate: StickyHeaderDelegate(
          height: hasBreadcrumbs ? 114 : 72,
          child: controlsRow,
        ),
      ),
      if (_isSelecting)
        SliverAppBar(
          pinned: true,
          // This isn't the scroll view's topmost sliver - the Synced
          // header above it already reserves status-bar space, so leaving
          // this at its default `primary: true` double-reserves it too,
          // showing up as a big empty gap above the toolbar.
          primary: false,
          automaticallyImplyLeading: false,
          toolbarHeight: 48,
          // No leading/actions slots - everything lives in `title`, wrapped
          // in the exact same 16px horizontal Padding as the controls row
          // above it, so the two rows' content lines up edge-to-edge
          // instead of relying on SliverAppBar's own leadingWidth/actions
          // insets (which don't match the controls row's).
          titleSpacing: 0,
          title: Padding(
            padding: const EdgeInsets.symmetric(horizontal: 16),
            child: Row(
              children: [
                IconButton(
                  icon: const Icon(Icons.close_rounded, size: 20),
                  tooltip: 'Cancel selection',
                  onPressed: _clearSelection,
                  visualDensity: VisualDensity.compact,
                ),
                const SizedBox(width: 8),
                Expanded(
                  child: Text(
                    '${selectedItems.length} selected',
                    style: theme.textTheme.titleSmall?.copyWith(
                      fontWeight: FontWeight.w700,
                    ),
                  ),
                ),
                for (final action in _buildSelectionActions(
                  provider,
                  selectedItems,
                ))
                  IconButton(
                    icon: Icon(action.icon, size: 20, color: action.color),
                    tooltip: action.label,
                    onPressed: action.onTap,
                    visualDensity: VisualDensity.compact,
                  ),
              ],
            ),
          ),
        ),

      // Files List / Grid
      if (provider.isLoading)
        const SliverFillRemaining(
          hasScrollBody: false,
          child: Center(child: CircularProgressIndicator()),
        )
      else if (provider.errorMessage != null)
        SliverFillRemaining(
          hasScrollBody: false,
          child: Center(
            child: Padding(
              padding: const EdgeInsets.all(24),
              child: Column(
                mainAxisAlignment: MainAxisAlignment.center,
                children: [
                  Icon(
                    Icons.error_outline_rounded,
                    size: 64,
                    color: colorScheme.error,
                  ),
                  const SizedBox(height: 16),
                  Text(
                    'WebDAV Sync Error',
                    style: theme.textTheme.titleLarge?.copyWith(
                      color: colorScheme.error,
                      fontWeight: FontWeight.bold,
                    ),
                  ),
                  const SizedBox(height: 8),
                  Text(
                    provider.errorMessage!,
                    textAlign: TextAlign.center,
                    style: theme.textTheme.bodyMedium?.copyWith(
                      color: colorScheme.onSurfaceVariant,
                    ),
                  ),
                  const SizedBox(height: 20),
                  FilledButton.icon(
                    onPressed: provider.refreshData,
                    icon: const Icon(Icons.refresh_rounded),
                    label: const Text('Retry Connection'),
                  ),
                ],
              ),
            ),
          ),
        )
      else if (provider.items.isEmpty)
        SliverFillRemaining(
          hasScrollBody: false,
          child: Center(
            child: Column(
              mainAxisAlignment: MainAxisAlignment.center,
              children: [
                Icon(
                  Icons.folder_open_rounded,
                  size: 64,
                  color: colorScheme.outlineVariant,
                ),
                const SizedBox(height: 12),
                Text(
                  'Folder is empty',
                  style: theme.textTheme.titleMedium?.copyWith(
                    color: colorScheme.onSurfaceVariant,
                  ),
                ),
              ],
            ),
          ),
        )
      else if (provider.isGridView)
        SliverPadding(
          key: const ValueKey('files-grid'),
          padding: const EdgeInsets.symmetric(horizontal: 20, vertical: 8),
          sliver: SliverGrid(
            gridDelegate: const SliverGridDelegateWithFixedCrossAxisCount(
              crossAxisCount: 2,
              childAspectRatio: 1.1,
              crossAxisSpacing: 12,
              mainAxisSpacing: 12,
            ),
            delegate: SliverChildBuilderDelegate((context, index) {
              final item = provider.items[index];
              return _buildGridCard(context, item, provider);
            }, childCount: provider.items.length),
          ),
        )
      else
        SliverPadding(
          key: const ValueKey('files-list'),
          padding: const EdgeInsets.symmetric(horizontal: 20, vertical: 8),
          sliver: SliverList(
            delegate: SliverChildBuilderDelegate((context, index) {
              final item = provider.items[index];
              return _buildListTile(context, item, provider);
            }, childCount: provider.items.length),
          ),
        ),

      // Fixed clearance so the last item isn't hidden behind the floating
      // nav bar, regardless of list length.
      const SliverToBoxAdapter(child: SizedBox(height: 100)),
      // For a short list this stretches the white card's background down to
      // the screen edge (matching the empty/loading/error states, which
      // already use SliverFillRemaining); for a long list that already fills
      // the viewport it contributes nothing extra.
      const SliverFillRemaining(hasScrollBody: false, child: SizedBox()),
    ];

    return PopScope(
      canPop: !_isSelecting && provider.pathStack.length <= 1,
      onPopInvokedWithResult: (didPop, result) {
        if (didPop) return;
        if (_isSelecting) {
          _clearSelection();
        } else {
          provider.navigateUp();
        }
      },
      child: SyncedHeaderScaffold(
        scrollController: widget.scrollController,
        provider: provider,
        actions: [
          IconButton(
            icon: const Icon(Icons.add_rounded),
            tooltip: 'New',
            onPressed: () => _showCreateMenu(context, provider),
          ),
          const MoreTabsButton(),
          const ProfileAvatarButton(),
        ],
        contentSlivers: contentSlivers,
      ),
    );
  }

  Future<void> _favoriteSelected(
    ServerProvider provider,
    List<NextcloudItem> items,
  ) async {
    final allFavorited = items.every((i) => i.isFavorite);
    for (final item in items) {
      if (item.isFavorite == allFavorited) {
        await provider.toggleItemFavorite(item);
      }
    }
    _clearSelection();
  }

  Future<void> _downloadSelected(
    BuildContext context,
    ServerProvider provider,
    List<NextcloudItem> items,
  ) async {
    final messenger = ScaffoldMessenger.of(context);
    messenger.showSnackBar(
      SnackBar(
        content: Text('Downloading ${items.length} item(s)...'),
        behavior: SnackBarBehavior.floating,
      ),
    );

    var succeeded = 0;
    for (final item in items) {
      if (item.isFolder) continue;
      try {
        final tempDir = await getTemporaryDirectory();
        final tempPath = p.join(tempDir.path, item.name);
        await provider.service!.downloadToFile(item.path, tempPath);
        final ext = p.extension(item.name).replaceFirst('.', '');
        final baseName = p.basenameWithoutExtension(item.name);
        await FileSaver.instance.saveFile(
          name: baseName,
          filePath: tempPath,
          ext: ext,
        );
        succeeded++;
      } catch (_) {
        // Reported in the summary snackbar below.
      }
    }

    _clearSelection();
    messenger.showSnackBar(
      SnackBar(
        content: Text('Downloaded $succeeded of ${items.length} item(s)'),
        behavior: SnackBarBehavior.floating,
      ),
    );
  }

  Future<void> _confirmDeleteSelected(
    BuildContext context,
    ServerProvider provider,
    List<NextcloudItem> items,
  ) async {
    final confirmed = await showDialog<bool>(
      context: context,
      builder: (dialogContext) {
        return AlertDialog(
          title: const Text('Delete Items'),
          content: Text(
            'Delete ${items.length} item(s) from the server? This cannot be undone.',
          ),
          actions: [
            TextButton(
              onPressed: () => Navigator.pop(dialogContext, false),
              child: const Text('Cancel'),
            ),
            FilledButton(
              style: FilledButton.styleFrom(
                backgroundColor: Theme.of(dialogContext).colorScheme.error,
              ),
              onPressed: () => Navigator.pop(dialogContext, true),
              child: const Text('Delete'),
            ),
          ],
        );
      },
    );
    if (confirmed != true || !context.mounted) return;

    final messenger = ScaffoldMessenger.of(context);
    var succeeded = 0;
    for (final item in items) {
      final success = await provider.deleteItem(item.path);
      if (success) succeeded++;
    }

    _clearSelection();
    messenger.showSnackBar(
      SnackBar(
        content: Text('Deleted $succeeded of ${items.length} item(s)'),
        behavior: SnackBarBehavior.floating,
      ),
    );
  }

  Widget _buildListTile(
    BuildContext context,
    NextcloudItem item,
    ServerProvider provider,
  ) {
    final theme = Theme.of(context);
    final colorScheme = theme.colorScheme;
    final isSelected = _selectedIds.contains(item.id);

    // No border radius here — the outer ClipRRect below is the only place
    // that rounds this tile's corners. Rounding it here too would give the
    // tile its own independent rounded edge, which becomes visible as a
    // stray floating corner while it slides during a swipe.
    final card = Material(
      color: isSelected
          ? colorScheme.primaryContainer.withValues(alpha: 0.5)
          : colorScheme.surfaceContainerLow,
      child: InkWell(
        onTap: () {
          if (_isSelecting) {
            _toggleSelection(item);
          } else if (item.isFolder) {
            provider.navigateToFolder(item.path);
          } else {
            _openFile(context, item, provider);
          }
        },
        onLongPress: () => _toggleSelection(item),
        child: Padding(
          padding: const EdgeInsets.symmetric(horizontal: 16, vertical: 12),
          child: Row(
            children: [
              SelectableThumbnail(
                isSelected: isSelected,
                size: 44,
                checkmarkSize: 24,
                child: _ItemThumbnail(
                  item: item,
                  provider: provider,
                  size: 44,
                  borderRadius: 12,
                  iconSize: 22,
                ),
              ),
              const SizedBox(width: 14),
              Expanded(
                child: Column(
                  crossAxisAlignment: CrossAxisAlignment.start,
                  children: [
                    Text(
                      item.name,
                      style: theme.textTheme.titleMedium?.copyWith(
                        fontWeight: FontWeight.w600,
                        fontSize: 14,
                      ),
                    ),
                    const SizedBox(height: 2),
                    Text(
                      item.isFolder
                          ? 'Folder'
                          : '${formatBytes(item.size)} • ${DateFormat.yMMMd().format(item.lastModified)}',
                      style: theme.textTheme.bodySmall?.copyWith(
                        color: colorScheme.onSurfaceVariant,
                      ),
                    ),
                  ],
                ),
              ),
            ],
          ),
        ),
      ),
    );

    final content = _isSelecting
        ? card
        : SwipeableItem(
            itemKey: ValueKey('file-${item.id}'),
            itemName: item.name,
            provider: provider,
            onFavorite: () => provider.toggleItemFavorite(item),
            onShare: () => ShareSheet.show(context, item),
            onDelete: () => _deleteViaSwipe(provider, item),
            child: card,
          );

    return Padding(
      padding: const EdgeInsets.only(bottom: 8),
      child: ClipRRect(borderRadius: BorderRadius.circular(16), child: content),
    );
  }

  Future<void> _deleteViaSwipe(
    ServerProvider provider,
    NextcloudItem item,
  ) async {
    final success = await provider.deleteItem(item.path);
    if (!mounted) return;
    ScaffoldMessenger.of(context).showSnackBar(
      SnackBar(
        content: Text(
          success ? 'Deleted ${item.name}' : 'Failed to delete ${item.name}',
        ),
        behavior: SnackBarBehavior.floating,
      ),
    );
  }

  Widget _buildGridCard(
    BuildContext context,
    NextcloudItem item,
    ServerProvider provider,
  ) {
    final isSelected = _selectedIds.contains(item.id);
    final isMedia =
        (item.type == NextcloudItemType.image ||
            item.type == NextcloudItemType.video) &&
        item.previewUrl != null;

    return Material(
      color: Theme.of(context).colorScheme.surfaceContainerLow,
      borderRadius: BorderRadius.circular(20),
      clipBehavior: Clip.antiAlias,
      child: InkWell(
        onTap: () {
          if (_isSelecting) {
            _toggleSelection(item);
          } else if (item.isFolder) {
            provider.navigateToFolder(item.path);
          } else {
            _openFile(context, item, provider);
          }
        },
        onLongPress: () => _toggleSelection(item),
        child: SelectableThumbnail(
          isSelected: isSelected,
          checkmarkSize: 32,
          child: isMedia
              ? _buildMediaGridContent(context, item, provider)
              : _buildPlainGridContent(context, item),
        ),
      ),
    );
  }

  /// Grid content for images/videos: the actual preview fills the whole
  /// card as a background, with the name/size legible over a bottom scrim
  /// — matching a Google Photos-style grid instead of a small icon badge.
  Widget _buildMediaGridContent(
    BuildContext context,
    NextcloudItem item,
    ServerProvider provider,
  ) {
    final theme = Theme.of(context);

    return LayoutBuilder(
      builder: (context, constraints) {
        final cachePixels =
            (constraints.maxWidth * MediaQuery.of(context).devicePixelRatio)
                .round();
        return Stack(
          fit: StackFit.expand,
          children: [
            Image.network(
              item.previewUrl!,
              headers: provider.service?.authHeaders,
              fit: BoxFit.cover,
              cacheWidth: cachePixels,
              cacheHeight: cachePixels,
              filterQuality: FilterQuality.low,
              gaplessPlayback: true,
              errorBuilder: (ctx, err, stack) =>
                  _buildPlainGridContent(context, item),
            ),
            if (item.type == NextcloudItemType.video)
              const Center(
                child: Icon(
                  Icons.play_circle_fill_rounded,
                  color: Colors.white,
                  size: 36,
                ),
              ),
            Positioned(
              left: 0,
              right: 0,
              bottom: 0,
              child: Container(
                padding: const EdgeInsets.fromLTRB(10, 20, 10, 8),
                decoration: const BoxDecoration(
                  gradient: LinearGradient(
                    begin: Alignment.topCenter,
                    end: Alignment.bottomCenter,
                    colors: [Colors.transparent, Colors.black87],
                  ),
                ),
                child: Column(
                  mainAxisSize: MainAxisSize.min,
                  crossAxisAlignment: CrossAxisAlignment.start,
                  children: [
                    Text(
                      item.name,
                      maxLines: 1,
                      overflow: TextOverflow.ellipsis,
                      style: theme.textTheme.titleSmall?.copyWith(
                        color: Colors.white,
                        fontWeight: FontWeight.w600,
                        fontSize: 12,
                      ),
                    ),
                    Text(
                      formatBytes(item.size),
                      style: theme.textTheme.bodySmall?.copyWith(
                        color: Colors.white70,
                        fontSize: 10,
                      ),
                    ),
                  ],
                ),
              ),
            ),
          ],
        );
      },
    );
  }

  /// Grid content for folders and non-previewable files: an icon badge
  /// with name/size below, since there's no meaningful preview to show.
  Widget _buildPlainGridContent(BuildContext context, NextcloudItem item) {
    final theme = Theme.of(context);
    final colorScheme = theme.colorScheme;
    final iconColor = _getIconColor(context, item.type);

    return Padding(
      padding: const EdgeInsets.all(14),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        mainAxisAlignment: MainAxisAlignment.spaceBetween,
        children: [
          Container(
            width: 40,
            height: 40,
            decoration: BoxDecoration(
              color: iconColor.withValues(alpha: 0.12),
              borderRadius: BorderRadius.circular(12),
            ),
            child: Icon(_getItemIcon(item.type), color: iconColor, size: 24),
          ),
          Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              Text(
                item.name,
                maxLines: 2,
                overflow: TextOverflow.ellipsis,
                style: theme.textTheme.titleMedium?.copyWith(
                  fontWeight: FontWeight.w600,
                  fontSize: 13,
                ),
              ),
              const SizedBox(height: 2),
              Text(
                item.isFolder ? 'Folder' : formatBytes(item.size),
                style: theme.textTheme.bodySmall?.copyWith(
                  color: colorScheme.onSurfaceVariant,
                  fontSize: 11,
                ),
              ),
            ],
          ),
        ],
      ),
    );
  }

  void _openFile(
    BuildContext context,
    NextcloudItem item,
    ServerProvider provider,
  ) {
    Navigator.push(
      context,
      FileViewerScreen.route(item: item, siblings: provider.items),
    );
  }

  void _showCreateMenu(BuildContext context, ServerProvider provider) {
    final colorScheme = Theme.of(context).colorScheme;
    showModalBottomSheet(
      context: context,
      backgroundColor: colorScheme.surfaceContainerHigh,
      showDragHandle: true,
      shape: const RoundedRectangleBorder(
        borderRadius: BorderRadius.vertical(top: Radius.circular(28)),
      ),
      builder: (sheetContext) {
        return SafeArea(
          child: Padding(
            padding: const EdgeInsets.symmetric(vertical: 12),
            child: Column(
              mainAxisSize: MainAxisSize.min,
              children: [
                ListTile(
                  leading: const Icon(Icons.upload_file_rounded),
                  title: const Text('Upload File'),
                  onTap: () {
                    Navigator.pop(sheetContext);
                    _pickAndUploadFile(context, provider);
                  },
                ),
                ListTile(
                  leading: const Icon(Icons.create_new_folder_outlined),
                  title: const Text('New Folder'),
                  onTap: () {
                    Navigator.pop(sheetContext);
                    _showCreateFolderDialog(context, provider);
                  },
                ),
              ],
            ),
          ),
        );
      },
    );
  }

  void _showCreateFolderDialog(BuildContext context, ServerProvider provider) {
    final controller = TextEditingController();

    showDialog(
      context: context,
      builder: (context) {
        return AlertDialog(
          title: const Text('Create New Folder'),
          content: TextField(
            controller: controller,
            decoration: const InputDecoration(
              labelText: 'Folder Name',
              hintText: 'e.g. Finance',
            ),
          ),
          actions: [
            TextButton(
              onPressed: () => Navigator.pop(context),
              child: const Text('Cancel'),
            ),
            FilledButton(
              onPressed: () async {
                final name = controller.text.trim();
                if (name.isNotEmpty) {
                  Navigator.pop(context);
                  final success = await provider.createFolder(name);
                  if (context.mounted) {
                    ScaffoldMessenger.of(context).showSnackBar(
                      SnackBar(
                        content: Text(
                          success
                              ? 'Created folder $name'
                              : 'Failed to create folder',
                        ),
                        behavior: SnackBarBehavior.floating,
                      ),
                    );
                  }
                }
              },
              child: const Text('Create'),
            ),
          ],
        );
      },
    );
  }

  Future<void> _pickAndUploadFile(
    BuildContext context,
    ServerProvider provider,
  ) async {
    final result = await FilePicker.pickFiles();
    if (result.isEmpty) return;
    final picked = result.first;
    if (picked.path == null) return;

    final progress = ValueNotifier<double?>(0);
    if (!context.mounted) return;

    showDialog(
      context: context,
      barrierDismissible: false,
      builder: (dialogContext) {
        return AlertDialog(
          title: Text('Uploading ${picked.name}'),
          content: ValueListenableBuilder<double?>(
            valueListenable: progress,
            builder: (context, value, _) =>
                LinearProgressIndicator(value: value),
          ),
        );
      },
    );

    bool success = false;
    try {
      success = await provider.uploadFileFromPath(
        picked.name,
        picked.path!,
        onProgress: (sent, total) {
          if (total > 0) progress.value = sent / total;
        },
      );
    } catch (_) {
      success = false;
    }

    if (context.mounted) {
      Navigator.pop(context); // close progress dialog
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(
          content: Text(
            success
                ? 'Uploaded ${picked.name} to Nextcloud'
                : 'Failed to upload ${picked.name}',
          ),
          behavior: SnackBarBehavior.floating,
        ),
      );
    }
  }
}