import 'dart:async';
import 'dart:convert';
import 'dart:io';
import 'dart:typed_data';

import '../../core/app_version.dart';
import '../models/jellyfin_library.dart';
import '../models/jellyfin_models.dart';

/// The small part of the Jellyfin API CarDash needs for Quick Connect.
abstract class JellyfinGateway {
  Future<JellyfinServerInfo> serverInfo(Uri baseUrl);

  Future<JellyfinQuickConnect> startQuickConnect(
    Uri baseUrl, {
    required String deviceId,
  });

  Future<bool> isQuickConnectApproved(Uri baseUrl, String secret);

  Future<JellyfinSession> authenticateQuickConnect(
    Uri baseUrl,
    String secret, {
    required String deviceId,
  });

  Future<JellyfinUser> currentUser(Uri baseUrl, String token);

  void close() {}
}

/// The music-library and playback-metadata calls layered on the same session.
/// The access token travels in the Authorization header only.
abstract class JellyfinLibraryGateway {
  Future<List<JellyfinTrack>> playedTracks(
    JellyfinConnection connection, {
    int limit = 50,
  });

  Future<List<JellyfinAlbum>> latestAddedAlbums(
    JellyfinConnection connection, {
    int limit = 5,
  });

  Future<List<JellyfinAlbum>> randomAlbums(
    JellyfinConnection connection, {
    required List<String> genres,
    int limit = 5,
  });

  Future<List<JellyfinTrack>> albumTracks(
    JellyfinConnection connection,
    String albumId,
  );

  Future<List<String>> musicLibraryIds(JellyfinConnection connection);

  Future<List<String>> genreNames(
    JellyfinConnection connection,
    String libraryId,
  );

  Future<Uint8List?> albumArtwork(
    JellyfinConnection connection,
    String albumId, {
    String? tag,
    int maxHeight = 400,
  });
}

/// Talks to Jellyfin over HTTPS. Quick Connect, library calls and artwork all
/// share one client; the token is never logged and only travels in the
/// Authorization header.
class HttpJellyfinGateway implements JellyfinGateway, JellyfinLibraryGateway {
  HttpJellyfinGateway({
    HttpClient Function()? clientFactory,
    this.timeout = const Duration(seconds: 10),
  }) : _clientFactory = clientFactory ?? HttpClient.new;

  final HttpClient Function() _clientFactory;
  final Duration timeout;
  HttpClient? _client;

  HttpClient get _http {
    return _client ??= _clientFactory()
      ..connectionTimeout = timeout
      ..idleTimeout = const Duration(seconds: 15);
  }

  @override
  Future<JellyfinServerInfo> serverInfo(Uri baseUrl) async {
    final response = await _send('GET', baseUrl.resolve('System/Info/Public'));
    if (response.status != HttpStatus.ok) {
      throw _statusError(response, notFound: 'No Jellyfin server found there.');
    }
    final json = _decode(response.body);
    final product = (json['ProductName'] as String?)?.toLowerCase();
    if (product != null && !product.contains('jellyfin')) {
      throw JellyfinException('That URL is not a Jellyfin server.');
    }
    final name = (json['ServerName'] as String?)?.trim();
    return JellyfinServerInfo(
      name: name == null || name.isEmpty ? 'Jellyfin' : name,
      version: (json['Version'] as String?) ?? '',
    );
  }

  @override
  Future<JellyfinQuickConnect> startQuickConnect(
    Uri baseUrl, {
    required String deviceId,
  }) async {
    final response = await _send(
      'POST',
      baseUrl.resolve('QuickConnect/Initiate'),
      deviceId: deviceId,
    );
    if (response.status != HttpStatus.ok) {
      if (response.status == HttpStatus.unauthorized ||
          response.status == HttpStatus.forbidden ||
          response.status == HttpStatus.notFound) {
        throw JellyfinException(
          'Quick Connect is disabled on this server. Enable it in Jellyfin '
          'settings and try again.',
        );
      }
      throw _statusError(response);
    }
    final json = _decode(response.body);
    final code = (json['Code'] as String?)?.trim();
    final secret = (json['Secret'] as String?)?.trim();
    if (code == null || code.isEmpty || secret == null || secret.isEmpty) {
      throw JellyfinException(
        'The server did not return a Quick Connect code.',
      );
    }
    return JellyfinQuickConnect(code: code, secret: secret);
  }

  @override
  Future<bool> isQuickConnectApproved(Uri baseUrl, String secret) async {
    final uri = baseUrl
        .resolve('QuickConnect/Connect')
        .replace(queryParameters: {'secret': secret});
    final response = await _send('GET', uri);
    if (response.status != HttpStatus.ok) {
      if (response.status == HttpStatus.notFound ||
          response.status == HttpStatus.unauthorized) {
        throw JellyfinException('The Quick Connect code expired.');
      }
      throw _statusError(response);
    }
    return _decode(response.body)['Authenticated'] == true;
  }

  @override
  Future<JellyfinSession> authenticateQuickConnect(
    Uri baseUrl,
    String secret, {
    required String deviceId,
  }) async {
    final response = await _send(
      'POST',
      baseUrl.resolve('Users/AuthenticateWithQuickConnect'),
      deviceId: deviceId,
      body: jsonEncode({'Secret': secret}),
      contentType: ContentType.json,
    );
    if (response.status == HttpStatus.unauthorized ||
        response.status == HttpStatus.forbidden) {
      throw JellyfinAuthException('The Quick Connect approval was rejected.');
    }
    if (response.status != HttpStatus.ok) {
      throw _statusError(response);
    }
    final json = _decode(response.body);
    final token = (json['AccessToken'] as String?)?.trim();
    final user = json['User'];
    if (token == null || token.isEmpty || user is! Map) {
      throw JellyfinException('The server did not return an access token.');
    }
    final id = (user['Id'] as String?)?.trim();
    final name = (user['Name'] as String?)?.trim();
    if (id == null || id.isEmpty || name == null || name.isEmpty) {
      throw JellyfinException('The server did not return the user profile.');
    }
    return JellyfinSession(accessToken: token, userId: id, userName: name);
  }

  @override
  Future<JellyfinUser> currentUser(Uri baseUrl, String token) async {
    final response = await _send(
      'GET',
      baseUrl.resolve('Users/Me'),
      token: token,
    );
    if (response.status == HttpStatus.unauthorized ||
        response.status == HttpStatus.forbidden) {
      throw JellyfinAuthException('The saved Jellyfin pairing is not valid.');
    }
    if (response.status != HttpStatus.ok) {
      throw _statusError(response);
    }
    final json = _decode(response.body);
    final id = (json['Id'] as String?)?.trim();
    final name = (json['Name'] as String?)?.trim();
    if (id == null || id.isEmpty || name == null || name.isEmpty) {
      throw JellyfinException('The server returned an unexpected profile.');
    }
    return JellyfinUser(id: id, name: name);
  }

  @override
  Future<List<JellyfinTrack>> playedTracks(
    JellyfinConnection connection, {
    int limit = 50,
  }) async {
    final uri = connection.baseUrl
        .resolve('Items')
        .replace(
          queryParameters: {
            'userId': connection.userId,
            'recursive': 'true',
            'includeItemTypes': 'Audio',
            'filters': 'IsPlayed',
            'sortBy': 'DatePlayed',
            'sortOrder': 'Descending',
            'limit': '$limit',
            'fields': 'Genres,AlbumArtist,Artists,Album,AlbumId,ParentId,RunTimeTicks',
            'enableUserData': 'true',
            'enableImageTypes': 'Primary',
            'imageTypeLimit': '1',
          },
        );
    final json = await _getJson(connection, uri);
    return _items(json)
        .map(JellyfinTrack.fromJson)
        .where((track) => track.id.isNotEmpty)
        .toList(growable: false);
  }

  @override
  Future<List<JellyfinAlbum>> latestAddedAlbums(
    JellyfinConnection connection, {
    int limit = 5,
  }) async {
    final uri = connection.baseUrl
        .resolve('Items/Latest')
        .replace(
          queryParameters: {
            'userId': connection.userId,
            'includeItemTypes': 'MusicAlbum',
            'limit': '$limit',
            'fields': 'Genres,DateCreated,ChildCount,AlbumArtist,Artists,PrimaryImageAspectRatio',
            'enableUserData': 'true',
            'enableImageTypes': 'Primary',
            'imageTypeLimit': '1',
          },
        );
    final list = await _getList(connection, uri);
    return list
        .whereType<Map>()
        .map(
          (entry) => JellyfinAlbum.fromJson(Map<String, dynamic>.from(entry)),
        )
        .where((album) => album.id.isNotEmpty)
        .toList(growable: false);
  }

  @override
  Future<List<JellyfinAlbum>> randomAlbums(
    JellyfinConnection connection, {
    required List<String> genres,
    int limit = 5,
  }) async {
    if (genres.isEmpty) return const [];
    final uri = connection.baseUrl
        .resolve('Items')
        .replace(
          queryParameters: {
            'userId': connection.userId,
            'recursive': 'true',
            'includeItemTypes': 'MusicAlbum',
            'genres': genres.join('|'),
            'sortBy': 'Random',
            'limit': '$limit',
            'fields': 'Genres,DateCreated,ChildCount,AlbumArtist,Artists,PrimaryImageAspectRatio',
            'enableUserData': 'true',
            'enableImageTypes': 'Primary',
            'imageTypeLimit': '1',
          },
        );
    final json = await _getJson(connection, uri);
    return _items(json)
        .map(JellyfinAlbum.fromJson)
        .where((album) => album.id.isNotEmpty)
        .toList(growable: false);
  }

  @override
  Future<List<JellyfinTrack>> albumTracks(
    JellyfinConnection connection,
    String albumId,
  ) async {
    if (albumId.isEmpty) return const [];
    final uri = connection.baseUrl
        .resolve('Items')
        .replace(
          queryParameters: {
            'userId': connection.userId,
            'parentId': albumId,
            'recursive': 'false',
            'includeItemTypes': 'Audio',
            'sortBy': 'ParentIndexNumber,IndexNumber',
            'fields': 'MediaSources,MediaStreams,Genres,AlbumArtist,Artists,IndexNumber,ParentIndexNumber,RunTimeTicks',
            'enableUserData': 'true',
          },
        );
    final json = await _getJson(connection, uri);
    return _items(json)
        .map(JellyfinTrack.fromJson)
        .where((track) => track.id.isNotEmpty)
        .toList(growable: false);
  }

  @override
  Future<List<String>> musicLibraryIds(JellyfinConnection connection) async {
    final uri = connection.baseUrl
        .resolve('UserViews')
        .replace(queryParameters: {'userId': connection.userId});
    final json = await _getJson(connection, uri);
    final ids = <String>[];
    for (final item in _items(json)) {
      if (item['CollectionType'] != 'music') continue;
      final id = (item['Id'] as String?)?.trim();
      if (id == null || id.isEmpty || ids.contains(id)) continue;
      ids.add(id);
    }
    return ids;
  }

  @override
  Future<List<String>> genreNames(
    JellyfinConnection connection,
    String libraryId,
  ) async {
    if (libraryId.isEmpty) return const [];
    final uri = connection.baseUrl
        .resolve('Genres')
        .replace(
          queryParameters: {'userId': connection.userId, 'parentId': libraryId},
        );
    final json = await _getJson(connection, uri);
    final names = <String>[];
    for (final item in _items(json)) {
      final name = (item['Name'] as String?)?.trim();
      if (name == null || name.isEmpty || names.contains(name)) continue;
      names.add(name);
    }
    return names;
  }

  /// Album artwork is binary; the text decoder in [_send] cannot be used.
  @override
  Future<Uint8List?> albumArtwork(
    JellyfinConnection connection,
    String albumId, {
    String? tag,
    int maxHeight = 400,
  }) async {
    if (albumId.isEmpty) return null;
    final uri = connection.baseUrl
        .resolve('Items/$albumId/Images/Primary')
        .replace(
          queryParameters: {
            'maxHeight': '$maxHeight',
            if (tag != null && tag.isNotEmpty) 'tag': tag,
          },
        );
    try {
      final request = await _http.getUrl(uri).timeout(timeout);
      request.headers.set(
        HttpHeaders.authorizationHeader,
        connection.authorizationHeader,
      );
      request.headers.set(HttpHeaders.acceptHeader, 'image/jpeg,image/png');
      final response = await request.close().timeout(timeout);
      if (response.statusCode != HttpStatus.ok) {
        await response.drain<void>();
        return null;
      }
      final builder = await response
          .fold<BytesBuilder>(BytesBuilder(copy: false), (buffer, chunk) {
            buffer.add(chunk);
            return buffer;
          })
          .timeout(timeout);
      final bytes = builder.takeBytes();
      return bytes.isEmpty ? null : bytes;
    } catch (_) {
      return null;
    }
  }

  @override
  void close() {
    _client?.close(force: true);
    _client = null;
  }

  Future<_JellyfinResponse> _send(
    String method,
    Uri uri, {
    String? deviceId,
    String? token,
    String? body,
    ContentType? contentType,
  }) async {
    try {
      final request = await _http.openUrl(method, uri).timeout(timeout);
      request.headers.set(
        HttpHeaders.authorizationHeader,
        _authorization(deviceId ?? 'cardash', token: token),
      );
      request.headers.set(HttpHeaders.acceptHeader, 'application/json');
      if (body != null) {
        request.headers.contentType = contentType ?? ContentType.text;
        request.write(body);
      }
      final response = await request.close().timeout(timeout);
      final text = await response
          .transform(utf8.decoder)
          .join()
          .timeout(timeout);
      return _JellyfinResponse(status: response.statusCode, body: text);
    } on JellyfinException {
      rethrow;
    } on SocketException {
      throw JellyfinUnreachable('Could not reach the server.');
    } on HandshakeException {
      throw JellyfinUnreachable('Could not establish a secure connection.');
    } on TimeoutException {
      throw JellyfinUnreachable('The server did not respond.');
    } on HttpException {
      throw JellyfinUnreachable('Could not reach the server.');
    } on FormatException {
      throw JellyfinException('The server returned an unexpected response.');
    }
  }

  String _authorization(String deviceId, {String? token}) {
    final parts = [
      'Client="CarDash"',
      'Device="CarDash"',
      'DeviceId="$deviceId"',
      'Version="$appVersion"',
      if (token != null) 'Token="$token"',
    ];
    return 'MediaBrowser ${parts.join(', ')}';
  }

  Future<Map<String, dynamic>> _getJson(
    JellyfinConnection connection,
    Uri uri,
  ) async {
    final response = await _send(
      'GET',
      uri,
      deviceId: connection.deviceId,
      token: connection.accessToken,
    );
    if (response.status != HttpStatus.ok) {
      throw _statusError(response);
    }
    return _decode(response.body);
  }

  Future<List<dynamic>> _getList(JellyfinConnection connection, Uri uri) async {
    final response = await _send(
      'GET',
      uri,
      deviceId: connection.deviceId,
      token: connection.accessToken,
    );
    if (response.status != HttpStatus.ok) {
      throw _statusError(response);
    }
    return _decodeList(response.body);
  }

  Map<String, dynamic> _decode(String body) {
    final decoded = jsonDecode(body);
    if (decoded is! Map<String, dynamic>) {
      throw JellyfinException('The server returned an unexpected response.');
    }
    return decoded;
  }

  List<dynamic> _decodeList(String body) {
    final decoded = jsonDecode(body);
    if (decoded is! List) {
      throw JellyfinException('The server returned an unexpected response.');
    }
    return decoded;
  }

  List<Map<String, dynamic>> _items(Map<String, dynamic> json) {
    final items = json['Items'];
    if (items is! List) return const [];
    return items
        .whereType<Map>()
        .map((entry) => Map<String, dynamic>.from(entry))
        .toList(growable: false);
  }

  JellyfinException _statusError(
    _JellyfinResponse response, {
    String? notFound,
  }) {
    if (response.status == HttpStatus.unauthorized ||
        response.status == HttpStatus.forbidden) {
      return JellyfinAuthException('The server rejected the credentials.');
    }
    if (response.status == HttpStatus.notFound && notFound != null) {
      return JellyfinException(notFound);
    }
    return JellyfinException('The server returned ${response.status}.');
  }
}

class _JellyfinResponse {
  const _JellyfinResponse({required this.status, required this.body});

  final int status;
  final String body;
}

/// Accepts `host`, `host:8096`, `https://host/jellyfin` and similar. Missing
/// schemes default to HTTPS; the result always ends in `/` so relative API
/// paths resolve under any configured path prefix.
Uri? normalizeJellyfinUrl(String input) {
  var value = input.trim();
  if (value.isEmpty) return null;
  if (!value.contains('://')) value = 'https://$value';
  final uri = Uri.tryParse(value);
  if (uri == null || uri.host.isEmpty) return null;
  if (uri.scheme != 'http' && uri.scheme != 'https') return null;
  final path = uri.path.endsWith('/') ? uri.path : '${uri.path}/';
  return Uri(
    scheme: uri.scheme,
    host: uri.host,
    port: uri.hasPort ? uri.port : null,
    path: path,
  );
}

/// The stored form of [normalizeJellyfinUrl], without the trailing slash.
String? displayJellyfinUrl(String input) {
  final uri = normalizeJellyfinUrl(input);
  if (uri == null) return null;
  final value = uri.toString();
  return value.endsWith('/') ? value.substring(0, value.length - 1) : value;
}