import 'package:flutter/material.dart';
import 'package:provider/provider.dart';

import '../playlists/playlists_screen.dart';
import '../settings/settings_screen.dart';
import '../shared/cover.dart';
import '../shared/sort_store.dart';
import '../shared/sub_tabs.dart';
import '../shared/sortable_song_list.dart';
import '../shared/theme.dart';
import 'album_list.dart';
import 'artist_list.dart';
import 'database.dart';
import 'library_service.dart';
import 'music_recognition_sheet.dart';
import 'permissions.dart';
import 'song_list.dart';

/// Startbildschirm: Kopfzeile mit Einstellungen/Suche/Musikerkennung,
/// Schnellzugriffe, Unterreiter (Songs/Künstler/Alben) und darunter der
/// jeweilige Inhalt. Bewusst ohne AppBar — die Kopfzeile ist Teil des Inhalts.
class MyMusicScreen extends StatefulWidget {
  const MyMusicScreen({super.key, this.onSearchTap, this.onFavoritesTap});

  /// Wechselt zum Suche-Tab; die Suche ist ein eigener Tab, kein eigener Screen.
  final VoidCallback? onSearchTap;

  /// Wechselt zum Favoriten-Tab.
  final VoidCallback? onFavoritesTap;

  @override
  State<MyMusicScreen> createState() => _MyMusicScreenState();
}

class _MyMusicScreenState extends State<MyMusicScreen> {
  /// 0 = Songs, 1 = Künstler, 2 = Alben.
  int _subTab = 0;

  @override
  Widget build(BuildContext context) {
    final db = context.read<MeloDb>();
    final lib = context.watch<LibraryService>();
    return SafeArea(
      bottom: false,
      child: Column(
        children: [
          _Header(onSearchTap: widget.onSearchTap),
          if (lib.permissionDenied)
            MaterialBanner(
              backgroundColor: Colors.red.shade900,
              content: const Text('Zugriff auf Musik verweigert. '
                  'Bitte in den Einstellungen erlauben.'),
              actions: [
                TextButton(
                  onPressed: openMusicPermissionSettings,
                  child: const Text('Einstellungen'),
                ),
              ],
            ),
          if (lib.scanError != null)
            MaterialBanner(
              backgroundColor: Colors.red.shade900,
              content: Text(lib.scanError!),
              actions: [
                TextButton(
                  onPressed: lib.dismissScanError,
                  child: const Text('Verwerfen'),
                ),
              ],
            ),
          if (lib.scanning)
            Padding(
              padding: const EdgeInsets.all(12),
              child: Column(
                children: [
                  const LinearProgressIndicator(),
                  const SizedBox(height: 6),
                  Text(
                    'Scanne … ${lib.scanDone}'
                    '${lib.scanTotal > 0 ? ' / ${lib.scanTotal}' : ''}',
                    style: const TextStyle(color: Colors.white54, fontSize: 12),
                  ),
                ],
              ),
            ),
          _QuickAccessRow(onFavoritesTap: widget.onFavoritesTap),
          SubTabs(
            labels: const ['Songs', 'Künstler', 'Alben'],
            index: _subTab,
            onChanged: (i) => setState(() => _subTab = i),
          ),
          Expanded(
            child: switch (_subTab) {
              1 => const ArtistListScreen(),
              2 => const AlbumListScreen(),
              _ => StreamBuilder<List<Song>>(
                  stream: db.watchSongs(),
                  builder: (context, snapshot) {
                    if (snapshot.hasError) {
                      return Center(
                        child: Text('Fehler: ${snapshot.error}',
                            style: const TextStyle(color: Colors.white54)),
                      );
                    }
                    final songs = snapshot.data ?? const <Song>[];
                    return SortableSongList(
                      songs: songs,
                      storeKey: SortStore.meineMusik,
                      empty:
                          lib.scanning ? const SizedBox.shrink() : const _Empty(),
                    );
                  },
                ),
            },
          ),
        ],
      ),
    );
  }
}

/// Einstellungen · Suchfeld · Musikerkennung.
class _Header extends StatelessWidget {
  const _Header({this.onSearchTap});
  final VoidCallback? onSearchTap;

  @override
  Widget build(BuildContext context) {
    return Padding(
      padding: const EdgeInsets.fromLTRB(8, 8, 8, 4),
      child: Row(
        children: [
          IconButton(
            tooltip: 'Einstellungen',
            icon: const Icon(Icons.tune),
            onPressed: () => Navigator.of(context).push(
              MaterialPageRoute(builder: (_) => const SettingsScreen()),
            ),
          ),
          Expanded(
            child: InkWell(
              onTap: onSearchTap,
              borderRadius: BorderRadius.circular(24),
              child: Container(
                height: 44,
                decoration: BoxDecoration(
                  color: MeloTheme.surfaceHigh,
                  borderRadius: BorderRadius.circular(24),
                ),
                child: const Row(
                  children: [
                    SizedBox(width: 14),
                    Icon(Icons.search, color: Colors.white54, size: 20),
                    SizedBox(width: 10),
                    Text(
                      'Titel, Künstler und Alben suchen',
                      style: TextStyle(color: Colors.white54, fontSize: 14),
                    ),
                  ],
                ),
              ),
            ),
          ),
          IconButton(
            tooltip: 'Musik erkennen',
            icon: const Icon(Icons.help_outline),
            onPressed: () => MusicRecognitionSheet.show(context),
          ),
        ],
      ),
    );
  }
}

/// Waagerecht scrollende Schnellzugriffe (Favoriten, Wiedergabelisten, …).
class _QuickAccessRow extends StatelessWidget {
  const _QuickAccessRow({this.onFavoritesTap});
  final VoidCallback? onFavoritesTap;

  @override
  Widget build(BuildContext context) {
    final db = context.read<MeloDb>();
    return SizedBox(
      height: 104,
      child: ListView(
        scrollDirection: Axis.horizontal,
        padding: const EdgeInsets.symmetric(horizontal: 12),
        children: [
          StreamBuilder<List<Song>>(
            stream: db.watchFavorites(),
            builder: (context, snapshot) {
              final favorites = snapshot.data ?? const <Song>[];
              return _QuickCard(
                icon: Icons.favorite,
                label: 'Favoriten',
                subtitle: '${favorites.length} Songs',
                coverPath: favorites.isEmpty ? null : favorites.first.coverPath,
                onTap: onFavoritesTap,
              );
            },
          ),
          StreamBuilder<List<Playlist>>(
            stream: db.watchPlaylists(),
            builder: (context, snapshot) {
              final playlists = snapshot.data ?? const <Playlist>[];
              return _QuickCard(
                icon: Icons.queue_music,
                label: 'Wiedergabelisten',
                subtitle: '${playlists.length} Listen',
                onTap: () => Navigator.of(context).push(
                  MaterialPageRoute(builder: (_) => const PlaylistsScreen()),
                ),
              );
            },
          ),
          StreamBuilder<List<Song>>(
            stream: db.watchRecent(limit: 50),
            builder: (context, snapshot) {
              final recent = snapshot.data ?? const <Song>[];
              return _QuickCard(
                icon: Icons.schedule,
                label: 'Zuletzt',
                subtitle: 'Neu hinzugefügt',
                coverPath: recent.isEmpty ? null : recent.first.coverPath,
                onTap: () => Navigator.of(context).push(
                  MaterialPageRoute(builder: (_) => const RecentlyAddedScreen()),
                ),
              );
            },
          ),
        ],
      ),
    );
  }
}

class _QuickCard extends StatelessWidget {
  const _QuickCard({
    required this.icon,
    required this.label,
    this.subtitle,
    this.coverPath,
    this.onTap,
  });

  final IconData icon;
  final String label;
  final String? subtitle;
  final String? coverPath;
  final VoidCallback? onTap;

  @override
  Widget build(BuildContext context) {
    return Padding(
      padding: const EdgeInsets.symmetric(horizontal: 4, vertical: 8),
      child: SizedBox(
        width: 150,
        child: Material(
          color: MeloTheme.surfaceHigh,
          borderRadius: BorderRadius.circular(12),
          clipBehavior: Clip.antiAlias,
          child: InkWell(
            onTap: onTap,
            child: Stack(
              fit: StackFit.expand,
              children: [
                if (coverPath != null)
                  Opacity(
                    opacity: 0.35,
                    child: CoverImage(
                      artUri: Uri.file(coverPath!),
                      size: 150,
                      radius: 0,
                    ),
                  ),
                Padding(
                  padding: const EdgeInsets.all(10),
                  child: Column(
                    crossAxisAlignment: CrossAxisAlignment.start,
                    mainAxisAlignment: MainAxisAlignment.spaceBetween,
                    children: [
                      Icon(icon, size: 22, color: Colors.white),
                      Column(
                        crossAxisAlignment: CrossAxisAlignment.start,
                        mainAxisSize: MainAxisSize.min,
                        children: [
                          Text(label,
                              maxLines: 1,
                              overflow: TextOverflow.ellipsis,
                              style: const TextStyle(
                                  fontWeight: FontWeight.w600, fontSize: 14)),
                          if (subtitle != null)
                            Text(subtitle!,
                                maxLines: 1,
                                overflow: TextOverflow.ellipsis,
                                style: const TextStyle(
                                    color: Colors.white54, fontSize: 11)),
                        ],
                      ),
                    ],
                  ),
                ),
              ],
            ),
          ),
        ),
      ),
    );
  }
}

/// Leerer Zustand mit direktem Weg zum Ordner-Scan.
class _Empty extends StatelessWidget {
  const _Empty();

  @override
  Widget build(BuildContext context) {
    final lib = context.read<LibraryService>();
    return Center(
      child: Column(
        mainAxisSize: MainAxisSize.min,
        children: [
          const Icon(Icons.library_music, size: 64, color: Colors.white24),
          const SizedBox(height: 12),
          const Text('Noch keine Musik',
              style: TextStyle(color: Colors.white54)),
          const SizedBox(height: 16),
          FilledButton.icon(
            icon: const Icon(Icons.create_new_folder_outlined),
            label: Text(addMusicLabel),
            onPressed: lib.pickFolderAndScan,
          ),
        ],
      ),
    );
  }
}

/// Vollbild-Liste der zuletzt hinzugefügten Songs (Schnellzugriff "Zuletzt").
class RecentlyAddedScreen extends StatelessWidget {
  const RecentlyAddedScreen({super.key});

  @override
  Widget build(BuildContext context) {
    final db = context.read<MeloDb>();
    return Scaffold(
      appBar: AppBar(title: const Text('Zuletzt hinzugefügt')),
      body: StreamBuilder<List<Song>>(
        stream: db.watchRecent(limit: 100),
        builder: (context, snapshot) {
          final songs = snapshot.data ?? const <Song>[];
          if (songs.isEmpty) {
            return const Center(
              child: Text('Noch nichts hinzugefügt',
                  style: TextStyle(color: Colors.white54)),
            );
          }
          return SongList(songs);
        },
      ),
    );
  }
}