import 'dart:io';
import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:file_picker/file_picker.dart';
import 'package:path_provider/path_provider.dart';
import 'package:permission_handler/permission_handler.dart';
import 'package:device_info_plus/device_info_plus.dart';
import 'package:spotiflac_android/l10n/l10n.dart';
import 'package:spotiflac_android/models/settings.dart';
import 'package:spotiflac_android/providers/settings_provider.dart';
import 'package:spotiflac_android/services/platform_bridge.dart';
import 'package:spotiflac_android/utils/app_bar_layout.dart';
import 'package:spotiflac_android/utils/file_access.dart';
import 'package:spotiflac_android/widgets/settings_group.dart';

class FilesSettingsPage extends ConsumerStatefulWidget {
  const FilesSettingsPage({super.key});

  @override
  ConsumerState<FilesSettingsPage> createState() => _FilesSettingsPageState();
}

class _FilesSettingsPageState extends ConsumerState<FilesSettingsPage> {
  int _androidSdkVersion = 0;
  bool _hasAllFilesAccess = false;
  bool _artistFolderFiltersExpanded = false;

  @override
  void initState() {
    super.initState();
    _initDeviceInfo();
  }

  Future<void> _initDeviceInfo() async {
    if (Platform.isAndroid) {
      final deviceInfo = DeviceInfoPlugin();
      final androidInfo = await deviceInfo.androidInfo;
      final sdkVersion = androidInfo.version.sdkInt;
      final hasAccess = await Permission.manageExternalStorage.isGranted;
      if (mounted) {
        setState(() {
          _androidSdkVersion = sdkVersion;
          _hasAllFilesAccess = hasAccess;
        });
      }
    }
  }

  Future<void> _requestAllFilesAccess() async {
    final status = await Permission.manageExternalStorage.request();
    if (status.isGranted) {
      ref.read(settingsProvider.notifier).setUseAllFilesAccess(true);
      if (mounted) setState(() => _hasAllFilesAccess = true);
    } else if (status.isPermanentlyDenied) {
      if (mounted) {
        final shouldOpen = await showDialog<bool>(
          context: context,
          builder: (context) => AlertDialog(
            title: Text(context.l10n.setupStorageAccessRequired),
            content: Text(context.l10n.allFilesAccessDeniedMessage),
            actions: [
              TextButton(
                onPressed: () => Navigator.pop(context, false),
                child: Text(context.l10n.dialogCancel),
              ),
              FilledButton(
                onPressed: () => Navigator.pop(context, true),
                child: Text(context.l10n.setupOpenSettings),
              ),
            ],
          ),
        );
        if (shouldOpen == true) await openAppSettings();
      }
    }
  }

  Future<void> _disableAllFilesAccess() async {
    ref.read(settingsProvider.notifier).setUseAllFilesAccess(false);
    if (mounted) {
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(content: Text(context.l10n.allFilesAccessDisabledMessage)),
      );
    }
  }

  @override
  Widget build(BuildContext context) {
    final settings = ref.watch(settingsProvider);
    final colorScheme = Theme.of(context).colorScheme;
    final topPadding = normalizedHeaderTopPadding(context);

    return PopScope(
      canPop: true,
      child: Scaffold(
        body: CustomScrollView(
          slivers: [
            SliverAppBar(
              expandedHeight: 120 + topPadding,
              collapsedHeight: kToolbarHeight,
              floating: false,
              pinned: true,
              backgroundColor: colorScheme.surface,
              surfaceTintColor: Colors.transparent,
              leading: IconButton(
                tooltip: MaterialLocalizations.of(context).backButtonTooltip,
                icon: const Icon(Icons.arrow_back),
                onPressed: () => Navigator.pop(context),
              ),
              flexibleSpace: LayoutBuilder(
                builder: (context, constraints) {
                  final maxHeight = 120 + topPadding;
                  final minHeight = kToolbarHeight + topPadding;
                  final expandRatio =
                      ((constraints.maxHeight - minHeight) /
                              (maxHeight - minHeight))
                          .clamp(0.0, 1.0);
                  final leftPadding = 56 - (32 * expandRatio);
                  return FlexibleSpaceBar(
                    expandedTitleScale: 1.0,
                    titlePadding: EdgeInsets.only(
                      left: leftPadding,
                      bottom: 16,
                    ),
                    title: Text(
                      context.l10n.settingsFiles,
                      style: TextStyle(
                        fontSize: 20 + (8 * expandRatio),
                        fontWeight: FontWeight.bold,
                        color: colorScheme.onSurface,
                      ),
                    ),
                  );
                },
              ),
            ),

            SliverToBoxAdapter(
              child: SettingsSectionHeader(
                title: context.l10n.setupDownloadLocationTitle,
              ),
            ),
            SliverToBoxAdapter(
              child: SettingsGroup(
                children: [
                  SettingsItem(
                    icon: Icons.folder_outlined,
                    title: context.l10n.downloadDirectory,
                    subtitle: settings.downloadDirectory.isEmpty
                        ? (Platform.isIOS
                              ? context.l10n.setupAppDocumentsFolder
                              : 'Music/SpotiFLAC')
                        : settings.downloadDirectory,
                    onTap: () => _pickDirectory(context, ref),
                    showDivider: false,
                  ),
                ],
              ),
            ),

            SliverToBoxAdapter(
              child: SettingsSectionHeader(
                title: context.l10n.sectionFileSettings,
              ),
            ),
            SliverToBoxAdapter(
              child: SettingsGroup(
                children: [
                  SettingsItem(
                    icon: Icons.text_fields,
                    title: context.l10n.downloadFilenameFormat,
                    subtitle: settings.filenameFormat,
                    onTap: () => _showFormatEditor(
                      context,
                      ref,
                      settings.filenameFormat,
                    ),
                  ),
                  SettingsItem(
                    icon: Icons.music_note_outlined,
                    title: context.l10n.downloadSingleFilenameFormat,
                    subtitle: settings.singleFilenameFormat,
                    onTap: () => _showFormatEditor(
                      context,
                      ref,
                      settings.singleFilenameFormat,
                      onSave: ref
                          .read(settingsProvider.notifier)
                          .setSingleFilenameFormat,
                      title: context.l10n.downloadSingleFilenameFormat,
                      description:
                          context.l10n.downloadSingleFilenameFormatDescription,
                    ),
                    showDivider: false,
                  ),
                ],
              ),
            ),

            SliverToBoxAdapter(
              child: SettingsSectionHeader(
                title: context.l10n.downloadFolderOrganization,
              ),
            ),
            SliverToBoxAdapter(
              child: SettingsGroup(
                children: [
                  SettingsSwitchItem(
                    icon: Icons.library_music_outlined,
                    title: context.l10n.downloadSeparateSinglesFolder,
                    subtitle: settings.separateSingles
                        ? context.l10n.downloadSeparateSinglesEnabled
                        : context.l10n.downloadSeparateSinglesDisabled,
                    value: settings.separateSingles,
                    onChanged: (value) => ref
                        .read(settingsProvider.notifier)
                        .setSeparateSingles(value),
                  ),
                  if (settings.separateSingles)
                    SettingsItem(
                      icon: Icons.folder_outlined,
                      title: context.l10n.downloadAlbumFolderStructure,
                      subtitle: _getAlbumFolderStructureLabel(
                        context,
                        settings.albumFolderStructure,
                      ),
                      onTap: () => _showAlbumFolderStructurePicker(
                        context,
                        ref,
                        settings.albumFolderStructure,
                      ),
                    ),
                  if (!settings.separateSingles)
                    SettingsItem(
                      icon: Icons.create_new_folder_outlined,
                      title: context.l10n.downloadFolderOrganization,
                      subtitle: _getFolderOrganizationLabel(
                        context,
                        settings.folderOrganization,
                      ),
                      onTap: () => _showFolderOrganizationPicker(
                        context,
                        ref,
                        settings.folderOrganization,
                      ),
                    ),
                  SettingsSwitchItem(
                    icon: Icons.playlist_play_outlined,
                    title: context.l10n.downloadCreatePlaylistSourceFolder,
                    subtitle: _getPlaylistFolderSubtitle(settings),
                    value: settings.createPlaylistFolder,
                    onChanged: (value) => ref
                        .read(settingsProvider.notifier)
                        .setCreatePlaylistFolder(value),
                  ),
                  SettingsSwitchItem(
                    icon: Icons.person_search_outlined,
                    title: context.l10n.downloadUseAlbumArtistForFolders,
                    subtitle: settings.useAlbumArtistForFolders
                        ? context
                              .l10n
                              .downloadUseAlbumArtistForFoldersAlbumSubtitle
                        : context
                              .l10n
                              .downloadUseAlbumArtistForFoldersTrackSubtitle,
                    value: settings.useAlbumArtistForFolders,
                    onChanged: (value) => ref
                        .read(settingsProvider.notifier)
                        .setUseAlbumArtistForFolders(value),
                  ),
                  SettingsItem(
                    icon: Icons.filter_alt_outlined,
                    title: context.l10n.downloadArtistNameFilters,
                    subtitle: _getArtistFolderFilterSubtitle(
                      context,
                      usePrimaryArtistOnly: settings.usePrimaryArtistOnly,
                      filterAlbumArtistContributors:
                          settings.filterContributingArtistsInAlbumArtist,
                    ),
                    trailing: Icon(
                      _artistFolderFiltersExpanded
                          ? Icons.expand_less
                          : Icons.expand_more,
                    ),
                    onTap: () => setState(() {
                      _artistFolderFiltersExpanded =
                          !_artistFolderFiltersExpanded;
                    }),
                    showDivider: !_artistFolderFiltersExpanded,
                  ),
                  if (_artistFolderFiltersExpanded) ...[
                    SettingsSwitchItem(
                      icon: Icons.person_outline,
                      title: context.l10n.downloadUsePrimaryArtistOnly,
                      subtitle: settings.usePrimaryArtistOnly
                          ? context.l10n.downloadUsePrimaryArtistOnlyEnabled
                          : context.l10n.downloadUsePrimaryArtistOnlyDisabled,
                      value: settings.usePrimaryArtistOnly,
                      onChanged: (value) => ref
                          .read(settingsProvider.notifier)
                          .setUsePrimaryArtistOnly(value),
                    ),
                    SettingsSwitchItem(
                      icon: Icons.group_remove_outlined,
                      title: context.l10n.downloadFilterContributing,
                      subtitle: settings.filterContributingArtistsInAlbumArtist
                          ? context.l10n.downloadFilterContributingEnabled
                          : context.l10n.downloadFilterContributingDisabled,
                      value: settings.filterContributingArtistsInAlbumArtist,
                      onChanged: (value) => ref
                          .read(settingsProvider.notifier)
                          .setFilterContributingArtistsInAlbumArtist(value),
                      showDivider: false,
                    ),
                  ],
                ],
              ),
            ),

            if (Platform.isAndroid && _androidSdkVersion >= 33) ...[
              SliverToBoxAdapter(
                child: SettingsSectionHeader(
                  title: context.l10n.sectionStorageAccess,
                ),
              ),
              SliverToBoxAdapter(
                child: SettingsGroup(
                  children: [
                    SettingsSwitchItem(
                      icon: Icons.folder_special_outlined,
                      title: context.l10n.allFilesAccess,
                      subtitle: _hasAllFilesAccess
                          ? context.l10n.allFilesAccessEnabledSubtitle
                          : context.l10n.allFilesAccessDisabledSubtitle,
                      value: _hasAllFilesAccess && settings.useAllFilesAccess,
                      onChanged: (value) {
                        if (value) {
                          _requestAllFilesAccess();
                        } else {
                          _disableAllFilesAccess();
                        }
                      },
                      showDivider: false,
                    ),
                  ],
                ),
              ),
              SliverToBoxAdapter(
                child: Padding(
                  padding: const EdgeInsets.fromLTRB(16, 8, 16, 0),
                  child: Row(
                    crossAxisAlignment: CrossAxisAlignment.start,
                    children: [
                      Icon(
                        Icons.info_outline,
                        size: 16,
                        color: colorScheme.onSurfaceVariant,
                      ),
                      const SizedBox(width: 8),
                      Expanded(
                        child: Text(
                          context.l10n.allFilesAccessDescription,
                          style: Theme.of(context).textTheme.bodySmall
                              ?.copyWith(color: colorScheme.onSurfaceVariant),
                        ),
                      ),
                    ],
                  ),
                ),
              ),
            ],

            const SliverToBoxAdapter(child: SizedBox(height: 32)),
          ],
        ),
      ),
    );
  }

  String _getAlbumFolderStructureLabel(BuildContext context, String structure) {
    switch (structure) {
      case 'album_only':
        return context.l10n.albumFolderAlbumOnlySubtitle;
      case 'artist_year_album':
        return context.l10n.albumFolderArtistYearAlbumSubtitle;
      case 'year_album':
        return context.l10n.albumFolderYearAlbumSubtitle;
      case 'artist_album_singles':
        return context.l10n.albumFolderArtistAlbumSinglesSubtitle;
      case 'artist_album_flat':
        return context.l10n.albumFolderArtistAlbumFlatSubtitle;
      default:
        return context.l10n.albumFolderArtistAlbumSubtitle;
    }
  }

  String _getFolderOrganizationLabel(BuildContext context, String value) {
    switch (value) {
      case 'playlist':
        return context.l10n.folderOrganizationByPlaylist;
      case 'artist':
        return context.l10n.folderOrganizationByArtist;
      case 'album':
        return context.l10n.folderOrganizationByAlbum;
      case 'artist_album':
        return context.l10n.folderOrganizationByArtistAlbum;
      default:
        return context.l10n.folderOrganizationNone;
    }
  }

  String _getPlaylistFolderSubtitle(AppSettings settings) {
    if (settings.folderOrganization == 'playlist') {
      return context.l10n.downloadCreatePlaylistSourceFolderRedundant;
    }
    if (settings.createPlaylistFolder) {
      return context.l10n.downloadCreatePlaylistSourceFolderEnabled;
    }
    return context.l10n.downloadCreatePlaylistSourceFolderDisabled;
  }

  String _getArtistFolderFilterSubtitle(
    BuildContext context, {
    required bool usePrimaryArtistOnly,
    required bool filterAlbumArtistContributors,
  }) {
    final statuses = <String>[
      usePrimaryArtistOnly ? 'Primary only: On' : 'Primary only: Off',
      filterAlbumArtistContributors
          ? 'Album Artist metadata: Primary only'
          : 'Album Artist metadata: Full',
    ];
    return statuses.join(' | ');
  }

  Future<void> _pickDirectory(BuildContext context, WidgetRef ref) async {
    if (Platform.isIOS) {
      _showIOSDirectoryOptions(context, ref);
    } else if (Platform.isAndroid) {
      _showAndroidDirectoryOptions(context, ref);
    }
  }

  Future<String> _getDefaultAndroidDirectory() async {
    const directMusicPath = '/storage/emulated/0/Music/SpotiFLAC';
    try {
      final musicDir = Directory(directMusicPath);
      if (!await musicDir.exists()) await musicDir.create(recursive: true);
      return musicDir.path;
    } catch (_) {}
    try {
      final externalDir = await getExternalStorageDirectory();
      if (externalDir != null) {
        final musicDir = Directory(
          '${externalDir.parent.parent.parent.parent.path}/Music/SpotiFLAC',
        );
        if (!await musicDir.exists()) await musicDir.create(recursive: true);
        return musicDir.path;
      }
    } catch (_) {}
    final appDir = await getApplicationDocumentsDirectory();
    final fallbackDir = Directory('${appDir.path}/SpotiFLAC');
    if (!await fallbackDir.exists()) await fallbackDir.create(recursive: true);
    return fallbackDir.path;
  }

  void _showAndroidDirectoryOptions(BuildContext context, WidgetRef ref) {
    final colorScheme = Theme.of(context).colorScheme;
    final settings = ref.read(settingsProvider);
    final isSafMode =
        settings.storageMode == 'saf' && settings.downloadTreeUri.isNotEmpty;
    showModalBottomSheet<void>(
      context: context,
      useRootNavigator: true,
      backgroundColor: colorScheme.surfaceContainerHigh,
      shape: const RoundedRectangleBorder(
        borderRadius: BorderRadius.vertical(top: Radius.circular(28)),
      ),
      builder: (ctx) => SafeArea(
        child: Column(
          mainAxisSize: MainAxisSize.min,
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            Padding(
              padding: const EdgeInsets.fromLTRB(24, 24, 24, 8),
              child: Text(
                context.l10n.setupDownloadLocationTitle,
                style: Theme.of(
                  ctx,
                ).textTheme.titleLarge?.copyWith(fontWeight: FontWeight.bold),
              ),
            ),
            Padding(
              padding: const EdgeInsets.fromLTRB(24, 0, 24, 16),
              child: Text(
                context.l10n.downloadLocationSubtitle,
                style: Theme.of(ctx).textTheme.bodyMedium?.copyWith(
                  color: colorScheme.onSurfaceVariant,
                ),
              ),
            ),
            ListTile(
              leading: Icon(Icons.folder_special, color: colorScheme.primary),
              title: Text(context.l10n.storageModeAppFolder),
              subtitle: Text(context.l10n.storageModeAppFolderSubtitle),
              trailing: !isSafMode ? const Icon(Icons.check) : null,
              onTap: () async {
                Navigator.pop(ctx);
                final defaultDir = await _getDefaultAndroidDirectory();
                final notifier = ref.read(settingsProvider.notifier);
                notifier.setStorageMode('app');
                notifier.setDownloadDirectory(defaultDir);
                notifier.setDownloadTreeUri('');
              },
            ),
            ListTile(
              leading: Icon(Icons.folder_open, color: colorScheme.primary),
              title: Text(context.l10n.storageModeSaf),
              subtitle: Text(context.l10n.storageModeSafSubtitle),
              trailing: isSafMode ? const Icon(Icons.check) : null,
              onTap: () async {
                Navigator.pop(ctx);
                final result = await PlatformBridge.pickSafTree();
                if (result != null) {
                  final treeUri = result['tree_uri'] as String? ?? '';
                  final displayName = result['display_name'] as String? ?? '';
                  if (treeUri.isNotEmpty) {
                    ref.read(settingsProvider.notifier).setStorageMode('saf');
                    ref
                        .read(settingsProvider.notifier)
                        .setDownloadTreeUri(
                          treeUri,
                          displayName: displayName.isNotEmpty
                              ? displayName
                              : treeUri,
                        );
                  }
                }
              },
            ),
            const SizedBox(height: 8),
          ],
        ),
      ),
    );
  }

  void _showIOSDirectoryOptions(BuildContext context, WidgetRef ref) {
    final colorScheme = Theme.of(context).colorScheme;
    showModalBottomSheet<void>(
      context: context,
      useRootNavigator: true,
      backgroundColor: colorScheme.surfaceContainerHigh,
      shape: const RoundedRectangleBorder(
        borderRadius: BorderRadius.vertical(top: Radius.circular(28)),
      ),
      builder: (ctx) => SafeArea(
        child: Column(
          mainAxisSize: MainAxisSize.min,
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            Padding(
              padding: const EdgeInsets.fromLTRB(24, 24, 24, 8),
              child: Text(
                context.l10n.setupDownloadLocationTitle,
                style: Theme.of(
                  context,
                ).textTheme.titleLarge?.copyWith(fontWeight: FontWeight.bold),
              ),
            ),
            Padding(
              padding: const EdgeInsets.fromLTRB(24, 0, 24, 16),
              child: Text(
                context.l10n.setupDownloadLocationIosMessage,
                style: Theme.of(context).textTheme.bodyMedium?.copyWith(
                  color: colorScheme.onSurfaceVariant,
                ),
              ),
            ),
            ListTile(
              leading: Icon(Icons.folder_special, color: colorScheme.primary),
              title: Text(context.l10n.setupAppDocumentsFolder),
              subtitle: Text(context.l10n.setupAppDocumentsFolderSubtitle),
              trailing: Icon(Icons.check_circle, color: colorScheme.primary),
              onTap: () async {
                final dir = await getApplicationDocumentsDirectory();
                ref
                    .read(settingsProvider.notifier)
                    .setDownloadDirectory(dir.path);
                if (ctx.mounted) Navigator.pop(ctx);
              },
            ),
            ListTile(
              leading: Icon(Icons.cloud, color: colorScheme.onSurfaceVariant),
              title: Text(context.l10n.setupChooseFromFiles),
              subtitle: Text(context.l10n.setupChooseFromFilesSubtitle),
              onTap: () async {
                Navigator.pop(ctx);
                if (Platform.isIOS) {
                  await Future<void>.delayed(const Duration(milliseconds: 250));
                }
                String? result;
                try {
                  result = await FilePicker.getDirectoryPath();
                } catch (e) {
                  if (ctx.mounted) {
                    ScaffoldMessenger.of(ctx).showSnackBar(
                      SnackBar(
                        content: Text(
                          ctx.l10n.snackbarFolderPickerFailed(e.toString()),
                        ),
                        backgroundColor: Theme.of(ctx).colorScheme.error,
                        duration: const Duration(seconds: 4),
                      ),
                    );
                  }
                  return;
                }
                if (result != null) {
                  if (Platform.isIOS) {
                    final validation = validateIosPath(result);
                    if (!validation.isValid) {
                      if (ctx.mounted) {
                        ScaffoldMessenger.of(ctx).showSnackBar(
                          SnackBar(
                            content: Text(
                              validation.errorReason ??
                                  context.l10n.setupIcloudNotSupported,
                            ),
                            backgroundColor: Theme.of(ctx).colorScheme.error,
                            duration: const Duration(seconds: 4),
                          ),
                        );
                      }
                      return;
                    }

                    final bookmark =
                        await PlatformBridge.createIosBookmarkFromPath(result);
                    if (bookmark == null || bookmark.isEmpty) {
                      if (ctx.mounted) {
                        ScaffoldMessenger.of(ctx).showSnackBar(
                          SnackBar(
                            content: Text(
                              ctx.l10n.snackbarFolderPickerFailed(
                                ctx.l10n.errorCouldNotKeepFolderAccess,
                              ),
                            ),
                            backgroundColor: Theme.of(ctx).colorScheme.error,
                            duration: const Duration(seconds: 4),
                          ),
                        );
                      }
                      return;
                    }

                    ref
                        .read(settingsProvider.notifier)
                        .setDownloadDirectory(result, iosBookmark: bookmark);
                    return;
                  }
                  ref
                      .read(settingsProvider.notifier)
                      .setDownloadDirectory(result);
                }
              },
            ),
            Padding(
              padding: const EdgeInsets.fromLTRB(24, 8, 24, 16),
              child: Container(
                padding: const EdgeInsets.all(12),
                decoration: BoxDecoration(
                  color: colorScheme.tertiaryContainer.withValues(alpha: 0.3),
                  borderRadius: BorderRadius.circular(12),
                ),
                child: Row(
                  children: [
                    Icon(
                      Icons.info_outline,
                      size: 20,
                      color: colorScheme.tertiary,
                    ),
                    const SizedBox(width: 12),
                    Expanded(
                      child: Text(
                        context.l10n.setupIosEmptyFolderWarning,
                        style: Theme.of(context).textTheme.bodySmall?.copyWith(
                          color: colorScheme.onTertiaryContainer,
                        ),
                      ),
                    ),
                  ],
                ),
              ),
            ),
            const SizedBox(height: 8),
          ],
        ),
      ),
    );
  }

  void _showFormatEditor(
    BuildContext context,
    WidgetRef ref,
    String current, {
    void Function(String)? onSave,
    String? title,
    String? description,
  }) {
    final colorScheme = Theme.of(context).colorScheme;
    final save =
        onSave ?? ref.read(settingsProvider.notifier).setFilenameFormat;

    showModalBottomSheet<void>(
      context: context,
      isScrollControlled: true,
      useSafeArea: true,
      backgroundColor: colorScheme.surface,
      shape: const RoundedRectangleBorder(
        borderRadius: BorderRadius.vertical(top: Radius.circular(28)),
      ),
      builder: (context) => _FilenameFormatEditorSheet(
        initialText: current,
        onSave: save,
        title: title,
        description: description,
      ),
    );
  }

  void _showAlbumFolderStructurePicker(
    BuildContext context,
    WidgetRef ref,
    String current,
  ) {
    showModalBottomSheet<void>(
      context: context,
      useRootNavigator: true,
      builder: (context) => SafeArea(
        child: Column(
          mainAxisSize: MainAxisSize.min,
          children: [
            for (final option in [
              (
                'artist_album',
                context.l10n.albumFolderArtistAlbum,
                context.l10n.albumFolderArtistAlbumSubtitle,
                Icons.folder_outlined,
              ),
              (
                'artist_year_album',
                context.l10n.albumFolderArtistYearAlbum,
                context.l10n.albumFolderArtistYearAlbumSubtitle,
                Icons.calendar_today_outlined,
              ),
              (
                'album_only',
                context.l10n.albumFolderAlbumOnly,
                context.l10n.albumFolderAlbumOnlySubtitle,
                Icons.album_outlined,
              ),
              (
                'year_album',
                context.l10n.albumFolderYearAlbum,
                context.l10n.albumFolderYearAlbumSubtitle,
                Icons.event_outlined,
              ),
              (
                'artist_album_singles',
                context.l10n.albumFolderArtistAlbumSingles,
                context.l10n.albumFolderArtistAlbumSinglesSubtitle,
                Icons.person_outlined,
              ),
              (
                'artist_album_flat',
                context.l10n.albumFolderArtistAlbumFlat,
                context.l10n.albumFolderArtistAlbumFlatSubtitle,
                Icons.person_outline_outlined,
              ),
            ])
              ListTile(
                leading: Icon(option.$4),
                title: Text(option.$2),
                subtitle: Text(option.$3),
                trailing: current == option.$1 ? const Icon(Icons.check) : null,
                onTap: () {
                  ref
                      .read(settingsProvider.notifier)
                      .setAlbumFolderStructure(option.$1);
                  Navigator.pop(context);
                },
              ),
          ],
        ),
      ),
    );
  }

  void _showFolderOrganizationPicker(
    BuildContext context,
    WidgetRef ref,
    String current,
  ) {
    final colorScheme = Theme.of(context).colorScheme;
    showModalBottomSheet<void>(
      context: context,
      useRootNavigator: true,
      backgroundColor: colorScheme.surfaceContainerHigh,
      isScrollControlled: true,
      shape: const RoundedRectangleBorder(
        borderRadius: BorderRadius.vertical(top: Radius.circular(28)),
      ),
      constraints: BoxConstraints(
        maxHeight: MediaQuery.of(context).size.height * 0.7,
      ),
      builder: (context) => SafeArea(
        child: SingleChildScrollView(
          child: Column(
            mainAxisSize: MainAxisSize.min,
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              Padding(
                padding: const EdgeInsets.fromLTRB(24, 24, 24, 8),
                child: Text(
                  context.l10n.downloadFolderOrganization,
                  style: Theme.of(
                    context,
                  ).textTheme.titleLarge?.copyWith(fontWeight: FontWeight.bold),
                ),
              ),
              Padding(
                padding: const EdgeInsets.fromLTRB(24, 0, 24, 16),
                child: Text(
                  context.l10n.folderOrganizationDescription,
                  style: Theme.of(context).textTheme.bodyMedium?.copyWith(
                    color: colorScheme.onSurfaceVariant,
                  ),
                ),
              ),
              for (final option in [
                (
                  'none',
                  context.l10n.folderOrganizationNone,
                  context.l10n.folderOrganizationNoneSubtitle,
                  'SpotiFLAC/Track.flac',
                ),
                (
                  'playlist',
                  context.l10n.folderOrganizationByPlaylist,
                  context.l10n.folderOrganizationByPlaylistSubtitle,
                  'SpotiFLAC/Playlist Name/Track.flac',
                ),
                (
                  'artist',
                  context.l10n.folderOrganizationByArtist,
                  context.l10n.folderOrganizationByArtistSubtitle,
                  'SpotiFLAC/Artist Name/Track.flac',
                ),
                (
                  'album',
                  context.l10n.folderOrganizationByAlbum,
                  context.l10n.folderOrganizationByAlbumSubtitle,
                  'SpotiFLAC/Album Name/Track.flac',
                ),
                (
                  'artist_album',
                  context.l10n.folderOrganizationByArtistAlbum,
                  context.l10n.folderOrganizationByArtistAlbumSubtitle,
                  'SpotiFLAC/Artist/Album/Track.flac',
                ),
              ])
                _FolderOption(
                  title: option.$2,
                  subtitle: option.$3,
                  example: option.$4,
                  isSelected: current == option.$1,
                  onTap: () {
                    ref
                        .read(settingsProvider.notifier)
                        .setFolderOrganization(option.$1);
                    Navigator.pop(context);
                  },
                ),
            ],
          ),
        ),
      ),
    );
  }
}

class _FolderOption extends StatelessWidget {
  final String title;
  final String subtitle;
  final String example;
  final bool isSelected;
  final VoidCallback onTap;
  const _FolderOption({
    required this.title,
    required this.subtitle,
    required this.example,
    required this.isSelected,
    required this.onTap,
  });

  @override
  Widget build(BuildContext context) {
    final colorScheme = Theme.of(context).colorScheme;
    return ListTile(
      contentPadding: const EdgeInsets.symmetric(horizontal: 24, vertical: 4),
      title: Text(title),
      subtitle: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          Text(subtitle),
          const SizedBox(height: 4),
          Text(
            example,
            style: TextStyle(
              fontFamily: 'monospace',
              fontSize: 11,
              color: colorScheme.primary,
            ),
          ),
        ],
      ),
      trailing: isSelected
          ? Icon(Icons.check_circle, color: colorScheme.primary)
          : Icon(Icons.circle_outlined, color: colorScheme.outline),
      onTap: onTap,
    );
  }
}


/// Bottom sheet for editing a filename format. Owns its controller and disposes
/// it in [dispose] to avoid use-after-dispose during the close animation.
class _FilenameFormatEditorSheet extends StatefulWidget {
  final String initialText;
  final void Function(String) onSave;
  final String? title;
  final String? description;

  const _FilenameFormatEditorSheet({
    required this.initialText,
    required this.onSave,
    this.title,
    this.description,
  });

  @override
  State<_FilenameFormatEditorSheet> createState() =>
      _FilenameFormatEditorSheetState();
}

class _FilenameFormatEditorSheetState
    extends State<_FilenameFormatEditorSheet> {
  static const _basicTags = [
    '{artist}',
    '{title}',
    '{album}',
    '{track}',
    '{year}',
    '{date}',
    '{disc}',
  ];
  static const _advancedTags = [
    '{track_raw}',
    '{track:02}',
    '{track:1}',
    '{date:%Y}',
    '{date:%Y-%m-%d}',
    '{disc_raw}',
    '{disc:02}',
  ];

  late final TextEditingController _controller;
  late bool _showAdvancedTags;

  @override
  void initState() {
    super.initState();
    _controller = TextEditingController(text: widget.initialText);
    _showAdvancedTags = RegExp(
      r'\{(?:track_raw|disc_raw|track:\d+|disc:\d+|date:[^}]+)\}',
      caseSensitive: false,
    ).hasMatch(widget.initialText);
  }

  @override
  void dispose() {
    _controller.dispose();
    super.dispose();
  }

  void _insertTag(String tag) {
    final text = _controller.text;
    final selection = _controller.selection;
    final start = selection.start >= 0 ? selection.start : text.length;
    final end = selection.end >= 0 ? selection.end : text.length;
    String insertion = tag;
    if (start > 0) {
      final before = text.substring(0, start);
      if (!before.trim().endsWith('-')) {
        insertion = ' - $tag';
      } else if (before.trim().endsWith('-') && !before.endsWith(' ')) {
        insertion = ' $tag';
      }
    }
    final newText = text.replaceRange(start, end, insertion);
    _controller.value = TextEditingValue(
      text: newText,
      selection: TextSelection.collapsed(offset: start + insertion.length),
    );
  }

  Widget _tagChip(ColorScheme colorScheme, String tag) {
    return ActionChip(
      label: Text(tag),
      onPressed: () => _insertTag(tag),
      backgroundColor: colorScheme.surfaceContainerHighest.withValues(
        alpha: 0.5,
      ),
      side: BorderSide.none,
      shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(12)),
      labelStyle: TextStyle(
        color: colorScheme.onSurface,
        fontWeight: FontWeight.w500,
      ),
    );
  }

  @override
  Widget build(BuildContext context) {
    final colorScheme = Theme.of(context).colorScheme;
    return Padding(
      padding: EdgeInsets.only(bottom: MediaQuery.of(context).viewInsets.bottom),
      child: SingleChildScrollView(
        child: SafeArea(
          child: Padding(
            padding: const EdgeInsets.all(24),
            child: Column(
              mainAxisSize: MainAxisSize.min,
              crossAxisAlignment: CrossAxisAlignment.stretch,
              children: [
                Center(
                  child: Container(
                    width: 32,
                    height: 4,
                    margin: const EdgeInsets.only(bottom: 24),
                    decoration: BoxDecoration(
                      color: colorScheme.outlineVariant,
                      borderRadius: BorderRadius.circular(2),
                    ),
                  ),
                ),
                Text(
                  widget.title ?? context.l10n.filenameFormat,
                  style: Theme.of(
                    context,
                  ).textTheme.headlineSmall?.copyWith(fontWeight: FontWeight.bold),
                  textAlign: TextAlign.center,
                ),
                const SizedBox(height: 8),
                Text(
                  widget.description ??
                      context.l10n.downloadFilenameDescription(
                        '{album}',
                        '{artist}',
                        '{date}',
                        '{disc}',
                        '{title}',
                        '{track}',
                        '{year}',
                      ),
                  style: Theme.of(context).textTheme.bodyMedium?.copyWith(
                    color: colorScheme.onSurfaceVariant,
                  ),
                  textAlign: TextAlign.center,
                ),
                const SizedBox(height: 24),
                TextField(
                  controller: _controller,
                  decoration: InputDecoration(
                    hintText: '{artist} - {title}',
                    filled: true,
                    fillColor: colorScheme.surfaceContainerHighest.withValues(
                      alpha: 0.3,
                    ),
                    border: OutlineInputBorder(
                      borderRadius: BorderRadius.circular(16),
                      borderSide: BorderSide.none,
                    ),
                  ),
                  autofocus: true,
                ),
                const SizedBox(height: 24),
                Text(
                  context.l10n.downloadFilenameInsertTag,
                  style: Theme.of(
                    context,
                  ).textTheme.titleSmall?.copyWith(fontWeight: FontWeight.bold),
                ),
                const SizedBox(height: 12),
                Wrap(
                  spacing: 8,
                  runSpacing: 8,
                  children: _basicTags
                      .map((tag) => _tagChip(colorScheme, tag))
                      .toList(),
                ),
                const SizedBox(height: 12),
                SwitchListTile(
                  value: _showAdvancedTags,
                  onChanged: (value) =>
                      setState(() => _showAdvancedTags = value),
                  contentPadding: EdgeInsets.zero,
                  title: Text(context.l10n.filenameShowAdvancedTags),
                  subtitle: Text(
                    context.l10n.filenameShowAdvancedTagsDescription,
                  ),
                ),
                if (_showAdvancedTags) ...[
                  const SizedBox(height: 8),
                  Wrap(
                    spacing: 8,
                    runSpacing: 8,
                    children: _advancedTags
                        .map((tag) => _tagChip(colorScheme, tag))
                        .toList(),
                  ),
                ],
                const SizedBox(height: 32),
                Row(
                  children: [
                    Expanded(
                      child: TextButton(
                        onPressed: () => Navigator.pop(context),
                        style: TextButton.styleFrom(
                          padding: const EdgeInsets.symmetric(vertical: 16),
                          shape: RoundedRectangleBorder(
                            borderRadius: BorderRadius.circular(16),
                          ),
                        ),
                        child: Text(context.l10n.dialogCancel),
                      ),
                    ),
                    const SizedBox(width: 12),
                    Expanded(
                      flex: 2,
                      child: FilledButton(
                        onPressed: () {
                          widget.onSave(_controller.text);
                          Navigator.pop(context);
                        },
                        style: FilledButton.styleFrom(
                          padding: const EdgeInsets.symmetric(vertical: 16),
                          shape: RoundedRectangleBorder(
                            borderRadius: BorderRadius.circular(16),
                          ),
                        ),
                        child: Text(context.l10n.dialogSave),
                      ),
                    ),
                  ],
                ),
                const SizedBox(height: 8),
              ],
            ),
          ),
        ),
      ),
    );
  }
}