import 'dart:async';
import 'dart:convert';
import 'dart:io';
import 'dart:math';
import 'package:flutter/foundation.dart';
import 'package:crypto/crypto.dart';
import 'package:http/http.dart' as http;
import 'package:shared_preferences/shared_preferences.dart';
import 'package:flutter_secure_storage/flutter_secure_storage.dart';
import 'cache_manager.dart';
import 'logger_service.dart';

class SubsonicSong {
  final String id;
  final String titel;
  final String kuenstler;
  final String album;
  final int dauerSekunden;
  final String? coverId;

  const SubsonicSong({
    required this.id,
    required this.titel,
    this.kuenstler = '',
    this.album = '',
    this.dauerSekunden = 0,
    this.coverId,
  });

  factory SubsonicSong.fromJson(Map<String, dynamic> j) => SubsonicSong(
    id: j['id'] as String,
    titel: j['title'] as String? ?? 'Unbekannt',
    kuenstler: j['artist'] as String? ?? '',
    album: j['album'] as String? ?? '',
    dauerSekunden: (j['duration'] as int?) ?? 0,
    coverId: j['coverArt'] as String?,
  );
}

class SubsonicAlbum {
  final String id;
  final String name;
  final String? coverId;
  final int songCount;

  const SubsonicAlbum({
    required this.id,
    required this.name,
    this.coverId,
    this.songCount = 0,
  });

  factory SubsonicAlbum.fromJson(Map<String, dynamic> j) => SubsonicAlbum(
    id: j['id'] as String,
    name: j['name'] as String? ?? j['title'] as String? ?? 'Unbekannt',
    coverId: j['coverArt'] as String?,
    songCount: (j['songCount'] as int?) ?? 0,
  );
}

/// Fehler einer Subsonic-Antwort mit `status:"failed"` (Navidrome liefert
/// dafür HTTP 200). Trägt die Server-Meldung, damit die UI sie zeigen kann.
class NavidromeException implements Exception {
  final String message;
  final int? code;
  NavidromeException(this.message, {this.code});
  @override
  String toString() => 'NavidromeException(${code ?? '-'}): $message';
}

class NavidromeService {
  final FlutterSecureStorage _secure = const FlutterSecureStorage();

  String _serverUrl = '';
  String _user = '';
  String _password = '';
  String _salt = '';
  String? _token;

  static const _version = '1.16.1';
  static const _client = 'Melo';

  void setCredentials(String url, String user, String password) {
    _serverUrl = url.endsWith('/') ? url.substring(0, url.length - 1) : url;
    _user = user;
    _password = password;
    final rng = Random.secure();
    _salt = base64Encode(List.generate(16, (_) => rng.nextInt(256)));
    _token = md5.convert(utf8.encode(_password + _salt)).toString();
  }

  Future<void> ladeGespeicherteZugangsdaten() async {
    try {
      final prefs = await SharedPreferences.getInstance();
      final url = prefs.getString('navidrome_url');
      final user = prefs.getString('navidrome_user');
      final pass = await _secure.read(key: 'navidrome_pass');
      if (url != null && user != null && pass != null && url.isNotEmpty) {
        setCredentials(url, user, pass);
      }
    } catch (e) {
      debugPrint('Fehler beim Laden der Navidrome-Zugangsdaten: $e');
    }
  }

  Future<void> speichereZugangsdaten(String url, String user, String password) async {
    setCredentials(url, user, password);
    try {
      final prefs = await SharedPreferences.getInstance();
      await prefs.setString('navidrome_url', url);
      await prefs.setString('navidrome_user', user);
      await _secure.write(key: 'navidrome_pass', value: password);
    } catch (e) {
      debugPrint('Fehler beim Speichern der Navidrome-Zugangsdaten: $e');
    }
  }

  Future<void> loescheZugangsdaten() async {
    _serverUrl = '';
    _user = '';
    _password = '';
    _salt = '';
    _token = null;
    try {
      final prefs = await SharedPreferences.getInstance();
      await prefs.remove('navidrome_url');
      await prefs.remove('navidrome_user');
      await _secure.delete(key: 'navidrome_pass');
    } catch (e) {
      debugPrint('Fehler beim Löschen der Navidrome-Zugangsdaten: $e');
    }
  }

  bool get istVerbunden => _serverUrl.isNotEmpty && _user.isNotEmpty;

  /// Dekodiert eine Subsonic-JSON-Antwort und wirft [NavidromeException],
  /// wenn der Server `status:"failed"` meldet (z. B. falsches Passwort) —
  /// solche Antworten kommen mit HTTP 200 und dürfen nicht als „leer" gelten.
  @visibleForTesting
  static Map<String, dynamic> parseSubsonic(String body) {
    final data = jsonDecode(body) as Map<String, dynamic>;
    final resp = data['subsonic-response'] as Map<String, dynamic>?;
    if (resp == null) {
      throw NavidromeException('Ungültige Server-Antwort (kein subsonic-response)');
    }
    if (resp['status'] == 'failed') {
      final err = resp['error'] as Map<String, dynamic>?;
      throw NavidromeException(
        (err?['message'] as String?) ?? 'Unbekannter Server-Fehler',
        code: err?['code'] as int?,
      );
    }
    return resp;
  }

  /// Liest Alben aus einer geprüften `getAlbumList2`-Antwort (ID3-basiert).
  @visibleForTesting
  static List<SubsonicAlbum> parseAlben(Map<String, dynamic> resp) {
    final list = resp['albumList2']?['album'] as List? ?? [];
    return list
        .map((j) => SubsonicAlbum.fromJson(j as Map<String, dynamic>))
        .toList();
  }

  Uri _uri(String endpoint, [Map<String, String>? extra]) {
    if (_token == null || _token!.isEmpty) {
      throw StateError('Navidrome ist nicht verbunden. Bitte zuerst Zugangsdaten setzen.');
    }
    final params = {
      'u': _user,
      't': _token!,
      's': _salt,
      'v': _version,
      'c': _client,
      'f': 'json',
    };
    if (extra != null) params.addAll(extra);
    return Uri.parse('$_serverUrl/rest/$endpoint').replace(queryParameters: params);
  }

  Future<bool> ping() async {
    try {
      final r = await http.get(_uri('ping.view')).timeout(const Duration(seconds: 10));
      if (r.statusCode != 200) {
        logger.warning('Navidrome Ping fehlgeschlagen (HTTP ${r.statusCode}): $_serverUrl');
        return false;
      }
      // Subsonic liefert auch bei falschem Passwort HTTP 200 → Body prüfen,
      // sonst meldet der Login fälschlich Erfolg (status:"failed").
      parseSubsonic(r.body);
      logger.info('✅ Navidrome Verbindung erfolgreich: $_serverUrl');
      return true;
    } on NavidromeException catch (e) {
      logger.warning('Navidrome Login abgelehnt: ${e.message}');
      return false;
    } catch (e) {
      // Details für die Diagnose: ohne URL/Exception-Typ ist im Log nicht
      // erkennbar, ob DNS, IPv6, TLS oder eine falsche URL die Ursache ist.
      // Bewusst NICHT die volle Ping-URI loggen — die enthält Token + Salt.
      final ziel = Uri.tryParse(_serverUrl);
      final art = switch (e) {
        TimeoutException() => 'TIMEOUT (10s überschritten)',
        SocketException(:final osError, :final address) =>
          'SOCKET (os=${osError?.message ?? '-'} code=${osError?.errorCode ?? '-'} '
              'addr=${address?.address ?? '-'} typ=${address?.type.name ?? '-'})',
        HandshakeException() => 'TLS-HANDSHAKE',
        HttpException() => 'HTTP',
        FormatException() => 'FORMAT (URL unparsbar?)',
        _ => 'SONSTIGE',
      };
      await logger.error(
        'Navidrome Ping Fehler [$art] '
        'url=$_serverUrl '
        'scheme=${ziel?.scheme ?? '-'} host=${ziel?.host ?? '-'} '
        'port=${ziel?.hasPort == true ? ziel?.port : '(default)'} '
        'typ=${e.runtimeType} '
        'msg=$e',
        e,
        StackTrace.current,
      );
      debugPrint('Navidrome Ping Fehler [$art] $_serverUrl: $e');
      return false;
    }
  }

  Future<List<SubsonicAlbum>> getAlben({int anzahl = 50}) async {
    try {
      // getAlbumList2 = ID3-basiert (wie getArtists) — der Folder-Endpoint
      // getAlbumList liefert bei tag-organisierten Navidrome-Libraries leer.
      final r = await http
          .get(_uri('getAlbumList2.view', {'type': 'newest', 'size': '$anzahl'}))
          .timeout(const Duration(seconds: 15));
      if (r.statusCode != 200) throw NavidromeException('HTTP ${r.statusCode}');
      return parseAlben(parseSubsonic(r.body));
    } catch (e) {
      await logger.error('Navidrome getAlben Fehler: $e', e, StackTrace.current);
      rethrow;
    }
  }

  Future<List<SubsonicSong>> getSongs(String albumId) async {
    try {
      final r = await http.get(_uri('getAlbum.view', {'id': albumId})).timeout(const Duration(seconds: 15));
      if (r.statusCode != 200) return [];
      final data = jsonDecode(r.body);
      final songs = data['subsonic-response']?['album']?['song'] as List? ?? [];
      return songs.map((j) => SubsonicSong.fromJson(j)).toList();
    } catch (e) {
      await logger.error('Navidrome getSongs Fehler: $e', e, StackTrace.current);
      return [];
    }
  }

  Uri streamUrl(String songId) {
    return _uri('stream.view', {'id': songId, 'format': 'raw'});
  }

  Uri? coverUrl(String coverId) {
    return _uri('getCoverArt.view', {'id': coverId});
  }

  Future<bool> setFavorite(String songId) async {
    try {
      final r = await http.get(_uri('star.view', {'id': songId})).timeout(const Duration(seconds: 10));
      return r.statusCode == 200;
    } catch (e) {
      await logger.error('Navidrome setFavorite Fehler: $e', e, StackTrace.current);
      return false;
    }
  }

  Future<bool> removeFavorite(String songId) async {
    try {
      final r = await http.get(_uri('unstar.view', {'id': songId})).timeout(const Duration(seconds: 10));
      return r.statusCode == 200;
    } catch (e) {
      await logger.error('Navidrome removeFavorite Fehler: $e', e, StackTrace.current);
      return false;
    }
  }

  Future<List<SubsonicSong>> getFavorites() async {
    try {
      final r = await http.get(_uri('getStarred.view')).timeout(const Duration(seconds: 15));
      if (r.statusCode != 200) return [];
      final data = jsonDecode(r.body);
      final songs = data['subsonic-response']?['starred']?['song'] as List? ?? [];
      return songs.map((j) => SubsonicSong.fromJson(j)).toList();
    } catch (e) {
      await logger.error('Navidrome getFavorites Fehler: $e', e, StackTrace.current);
      return [];
    }
  }

  Future<List<SubsonicArtist>> getArtists() async {
    try {
      final r = await http.get(_uri('getArtists.view')).timeout(const Duration(seconds: 15));
      if (r.statusCode != 200) throw NavidromeException('HTTP ${r.statusCode}');
      final resp = parseSubsonic(r.body);
      final indexData = resp['artists']?['index'] as List? ?? [];
      final artists = <SubsonicArtist>[];
      for (final idx in indexData) {
        final artistList = idx['artist'] as List? ?? [];
        for (final a in artistList) {
          artists.add(SubsonicArtist.fromJson(a as Map<String, dynamic>));
        }
      }
      return artists;
    } catch (e) {
      await logger.error('Navidrome getArtists Fehler: $e', e, StackTrace.current);
      rethrow;
    }
  }

  Future<List<SubsonicSong>> getArtistSongs(String artistId) async {
    try {
      final r = await http.get(_uri('getArtist.view', {'id': artistId})).timeout(const Duration(seconds: 15));
      if (r.statusCode != 200) return [];
      final data = jsonDecode(r.body);
      final albums = data['subsonic-response']?['artist']?['album'] as List? ?? [];
      final songs = <SubsonicSong>[];
      for (final album in albums) {
        final albumSongs = album['song'] as List? ?? [];
        for (final song in albumSongs) {
          songs.add(SubsonicSong.fromJson(song));
        }
      }
      return songs;
    } catch (e) {
      await logger.error('Navidrome getArtistSongs Fehler: $e', e, StackTrace.current);
      return [];
    }
  }

  Future<Lyrics> getLyrics(String songId) async {
    try {
      final r = await http.get(_uri('getLyrics.view', {'id': songId})).timeout(const Duration(seconds: 10));
      if (r.statusCode != 200) return Lyrics.empty();
      final data = jsonDecode(r.body);
      final lyrics = data['subsonic-response']?['lyrics']?['value'] as String?;
      return Lyrics.fromText(lyrics);
    } catch (e) {
      await logger.error('Navidrome getLyrics Fehler: $e', e, StackTrace.current);
      return Lyrics.empty();
    }
  }

  Future<Uri?> streamAndCacheToLocal(String songId, CacheManager cache) async {
    try {
      final streamUri = streamUrl(songId);
      final cacheFile = await cache.getCacheFile(streamUri.toString());

      if (await cacheFile.exists()) {
        debugPrint('Cache-Hit: ${cacheFile.path}');
        return Uri.file(cacheFile.path);
      }

      debugPrint('Cache-Miss: Starten download zu ${cacheFile.path}');
      final request = http.Request('GET', streamUri);
      final response = await http.Client().send(request).timeout(const Duration(seconds: 30));

      if (response.statusCode != 200) {
        await logger.error('Stream-Fehler: HTTP ${response.statusCode}');
        return streamUri;
      }

      final sink = cacheFile.openWrite();
      await for (final chunk in response.stream) {
        sink.add(chunk);
      }
      await sink.close();

      debugPrint('Cache-Speicherung erfolgreich: ${cacheFile.path}');
      return Uri.file(cacheFile.path);
    } catch (e) {
      await logger.error('streamAndCacheToLocal Fehler: $e', e, StackTrace.current);
      return streamUrl(songId);
    }
  }

  /// Speichert die aktuelle Wiedergabe-Position für einen Song zum Server.
  /// Subsonic-API: scrobble.view mit `submission=true` und Position in Sekunden.
  Future<void> scrobble(String songId, int positionSeconds) async {
    if (!istVerbunden) return;
    try {
      final uri = _uri('scrobble.view', {
        'id': songId,
        'submission': 'true',
        'position': positionSeconds.toString(),
      });
      await http.get(uri).timeout(const Duration(seconds: 10));
      debugPrint('Scrobble erfolgreich: Song=$songId, Position=${positionSeconds}s');
    } catch (e) {
      await logger.error('Scrobble Fehler: $e', e, StackTrace.current);
    }
  }

  /// Lädt die gespeicherte Wiedergabe-Position für einen Song vom Server.
  /// Gibt Position in Millisekunden zurück oder null wenn nicht gespeichert.
  Future<int?> getBookmark(String songId) async {
    if (!istVerbunden) return null;
    try {
      final uri = _uri('getBookmarks.view', {'id': songId});
      final response = await http.get(uri).timeout(const Duration(seconds: 10));
      if (response.statusCode != 200) return null;

      final json = jsonDecode(response.body) as Map<String, dynamic>;
      final subsonicResponse = json['subsonic-response'] as Map<String, dynamic>?;
      if (subsonicResponse == null) return null;

      final bookmarks = subsonicResponse['bookmark'] as List<dynamic>?;
      if (bookmarks == null || bookmarks.isEmpty) return null;

      final position = (bookmarks[0] as Map<String, dynamic>)['position'] as int?;
      if (position == null) return null;
      debugPrint('Bookmark geladen: Song=$songId, Position=${position}ms');
      return position;
    } catch (e) {
      await logger.error('Bookmark Fehler: $e', e, StackTrace.current);
      return null;
    }
  }

  /// Lädt alle Playlisten vom Server.
  Future<List<SubsonicPlaylist>> getPlaylists() async {
    if (!istVerbunden) return [];
    try {
      final uri = _uri('getPlaylists.view');
      final response = await http.get(uri).timeout(const Duration(seconds: 10));
      if (response.statusCode != 200) return [];

      final json = jsonDecode(response.body) as Map<String, dynamic>;
      final subsonicResponse = json['subsonic-response'] as Map<String, dynamic>?;
      if (subsonicResponse == null) return [];

      final playlists = subsonicResponse['playlists'] as List<dynamic>?;
      if (playlists == null) return [];

      return playlists
          .cast<Map<String, dynamic>>()
          .map(SubsonicPlaylist.fromJson)
          .toList();
    } catch (e) {
      await logger.error('getPlaylists Fehler: $e', e, StackTrace.current);
      return [];
    }
  }

  /// Lädt alle Songs einer Playlist vom Server.
  Future<List<SubsonicSong>> getPlaylistSongs(String playlistId) async {
    if (!istVerbunden) return [];
    try {
      final uri = _uri('getPlaylist.view', {'id': playlistId});
      final response = await http.get(uri).timeout(const Duration(seconds: 10));
      if (response.statusCode != 200) return [];

      final json = jsonDecode(response.body) as Map<String, dynamic>;
      final subsonicResponse = json['subsonic-response'] as Map<String, dynamic>?;
      if (subsonicResponse == null) return [];

      final playlist = subsonicResponse['playlist'] as Map<String, dynamic>?;
      if (playlist == null) return [];

      final songs = playlist['entry'] as List<dynamic>?;
      if (songs == null) return [];

      return songs.cast<Map<String, dynamic>>().map(SubsonicSong.fromJson).toList();
    } catch (e) {
      await logger.error('getPlaylistSongs Fehler: $e', e, StackTrace.current);
      return [];
    }
  }
}

class SubsonicArtist {
  final String id;
  final String name;

  const SubsonicArtist({
    required this.id,
    required this.name,
  });

  factory SubsonicArtist.fromJson(Map<String, dynamic> j) => SubsonicArtist(
    id: j['id'] as String,
    name: j['name'] as String? ?? 'Unbekannt',
  );
}

class SubsonicPlaylist {
  final String id;
  final String name;
  final String? comment;
  final int songCount;

  const SubsonicPlaylist({
    required this.id,
    required this.name,
    this.comment,
    this.songCount = 0,
  });

  factory SubsonicPlaylist.fromJson(Map<String, dynamic> j) => SubsonicPlaylist(
    id: j['id'] as String,
    name: j['name'] as String? ?? 'Unbekannt',
    comment: j['comment'] as String?,
    songCount: (j['songCount'] as int?) ?? 0,
  );
}

class Lyrics {
  final String? text;
  final bool isEmpty;

  const Lyrics({
    this.text,
    this.isEmpty = true,
  });

  factory Lyrics.empty() => const Lyrics(isEmpty: true);
  factory Lyrics.fromText(String? text) =>
      Lyrics(text: text, isEmpty: text?.isEmpty ?? true);
}