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

import '../player/audio_handler.dart';
import '../services/navidrome_service.dart';

/// Online-Tab: durchsucht den verbundenen Navidrome-Server. Abgespielte
/// Titel werden vom [MeloAudioHandler] automatisch lokal zwischengespeichert
/// und stehen danach offline zur Verfügung.
class DownloadsScreen extends StatelessWidget {
  const DownloadsScreen({super.key});

  @override
  Widget build(BuildContext context) {
    return const SafeArea(
      bottom: false,
      child: Column(
        children: [
          Padding(
            padding: EdgeInsets.fromLTRB(20, 16, 20, 4),
            child: Align(
              alignment: Alignment.centerLeft,
              child: Text('Online',
                  style: TextStyle(fontSize: 24, fontWeight: FontWeight.w700)),
            ),
          ),
          Expanded(child: _ServerBrowser()),
        ],
      ),
    );
  }
}

class _ServerBrowser extends StatefulWidget {
  const _ServerBrowser();

  @override
  State<_ServerBrowser> createState() => _ServerBrowserState();
}

class _ServerBrowserState extends State<_ServerBrowser> {
  late final NavidromeService _nav = NavidromeService();
  List<SubsonicAlbum> _albums = [];
  List<SubsonicArtist> _artists = [];
  bool _loading = false;
  bool _showArtists = false;
  String? _error;

  @override
  void initState() {
    super.initState();
    _nav.ladeGespeicherteZugangsdaten().then((_) {
      if (_nav.istVerbunden && mounted) {
        _loadAlbums();
      }
    });
  }

  Future<void> _loadAlbums() async {
    if (!_nav.istVerbunden) {
      return;
    }
    setState(() {
      _loading = true;
      _error = null;
    });
    try {
      final alben = await _nav.getAlben(anzahl: 50);
      if (mounted) {
        setState(() {
          _albums = alben;
          _loading = false;
        });
      }
    } catch (e) {
      if (mounted) {
        setState(() {
          _loading = false;
          _error = e is NavidromeException ? e.message : 'Verbindungsfehler';
        });
      }
      debugPrint('Fehler beim Laden der Alben: $e');
    }
  }

  Future<void> _loadArtists() async {
    if (!_nav.istVerbunden) return;
    setState(() {
      _loading = true;
      _error = null;
    });
    try {
      final artists = await _nav.getArtists();
      if (mounted) {
        setState(() {
          _artists = artists;
          _loading = false;
        });
      }
    } catch (e) {
      if (mounted) {
        setState(() {
          _loading = false;
          _error = e is NavidromeException ? e.message : 'Verbindungsfehler';
        });
      }
      debugPrint('Fehler beim Laden der Künstler: $e');
    }
  }

  @override
  Widget build(BuildContext context) {
    if (!_nav.istVerbunden) {
      return Center(
        child: Column(
          mainAxisSize: MainAxisSize.min,
          children: [
            const Icon(Icons.cloud_off, size: 64, color: Colors.white24),
            const SizedBox(height: 12),
            const Text('Musikserver nicht verbunden',
                style: TextStyle(color: Colors.white54)),
            const SizedBox(height: 12),
            const Text('Gehe zu Einstellungen → Navidrome zum Verbinden',
                style: TextStyle(color: Colors.white30, fontSize: 12)),
          ],
        ),
      );
    }

    if (_loading) {
      return const Center(
        child: CircularProgressIndicator(color: Colors.redAccent),
      );
    }

    if (_albums.isEmpty) {
      final hatFehler = _error != null;
      return Center(
        child: Padding(
          padding: const EdgeInsets.symmetric(horizontal: 32),
          child: Column(
            mainAxisSize: MainAxisSize.min,
            children: [
              Icon(hatFehler ? Icons.error_outline : Icons.album,
                  size: 64,
                  color: hatFehler ? Colors.redAccent : Colors.white24),
              const SizedBox(height: 12),
              Text(
                hatFehler ? 'Serverfehler: $_error' : 'Keine Alben geladen',
                textAlign: TextAlign.center,
                style: const TextStyle(color: Colors.white54),
              ),
              const SizedBox(height: 16),
              FilledButton.icon(
                icon: const Icon(Icons.refresh),
                label: const Text('Erneut versuchen'),
                onPressed: _loadAlbums,
              ),
            ],
          ),
        ),
      );
    }

    return Column(
      children: [
        Padding(
          padding: const EdgeInsets.all(12),
          child: Row(
            children: [
              Expanded(
                child: FilledButton(
                  onPressed: () => setState(() {
                    _showArtists = false;
                    if (_albums.isEmpty) _loadAlbums();
                  }),
                  style: FilledButton.styleFrom(
                    backgroundColor: !_showArtists ? Colors.redAccent : Colors.grey.shade700,
                  ),
                  child: const Text('📀 Alben'),
                ),
              ),
              const SizedBox(width: 8),
              Expanded(
                child: FilledButton(
                  onPressed: () => setState(() {
                    _showArtists = true;
                    if (_artists.isEmpty) _loadArtists();
                  }),
                  style: FilledButton.styleFrom(
                    backgroundColor: _showArtists ? Colors.redAccent : Colors.grey.shade700,
                  ),
                  child: const Text('🎤 Künstler'),
                ),
              ),
            ],
          ),
        ),
        Expanded(
          child: _showArtists
              ? ListView.builder(
                  padding: const EdgeInsets.symmetric(horizontal: 12),
                  itemCount: _artists.length,
                  itemBuilder: (context, i) {
                    final artist = _artists[i];
                    return Card(
                      margin: const EdgeInsets.only(bottom: 8),
                      child: ListTile(
                        leading: const Icon(Icons.person, size: 48),
                        title: Text(artist.name),
                        onTap: () => _playArtist(artist),
                      ),
                    );
                  },
                )
              : ListView.builder(
                  padding: const EdgeInsets.symmetric(horizontal: 12),
                  itemCount: _albums.length,
                  itemBuilder: (context, i) {
                    final album = _albums[i];
                    return Card(
                      margin: const EdgeInsets.only(bottom: 8),
                      child: ListTile(
                        leading: Icon(
                          Icons.album,
                          size: 48,
                          color: Colors.redAccent.withValues(alpha: 0.5),
                        ),
                        title: Text(album.name),
                        subtitle: Text('${album.songCount} Songs'),
                        onTap: () => _playAlbum(album),
                      ),
                    );
                  },
                ),
        ),
      ],
    );
  }

  Future<void> _playAlbum(SubsonicAlbum album) async {
    final handler = context.read<MeloAudioHandler>();
    try {
      final songs = await _nav.getSongs(album.id);
      if (songs.isEmpty) {
        if (!mounted) {
          return;
        }
        final messenger = ScaffoldMessenger.of(context);
        messenger.showSnackBar(
          const SnackBar(content: Text('Album hat keine Songs')),
        );
        return;
      }
      final items = songs
          .map((s) => MediaItem(
            id: _nav.streamUrl(s.id).toString(),
            title: s.titel,
            artist: s.kuenstler,
            album: s.album,
            duration: Duration(seconds: s.dauerSekunden),
          ))
          .toList();
      await handler.loadPlaylist(items);
    } catch (e) {
      if (!mounted) {
        return;
      }
      final messenger = ScaffoldMessenger.of(context);
      messenger.showSnackBar(
        SnackBar(content: Text('Fehler: $e')),
      );
    }
  }

  Future<void> _playArtist(SubsonicArtist artist) async {
    final handler = context.read<MeloAudioHandler>();
    try {
      final songs = await _nav.getArtistSongs(artist.id);
      if (songs.isEmpty) {
        if (!mounted) return;
        ScaffoldMessenger.of(context).showSnackBar(
          const SnackBar(content: Text('Künstler hat keine Songs')),
        );
        return;
      }
      final items = songs
          .map((s) => MediaItem(
            id: _nav.streamUrl(s.id).toString(),
            title: s.titel,
            artist: s.kuenstler,
            album: s.album,
            duration: Duration(seconds: s.dauerSekunden),
          ))
          .toList();
      await handler.loadPlaylist(items);
    } catch (e) {
      if (!mounted) return;
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(content: Text('Fehler: $e')),
      );
    }
  }
}