class PotatoDataSourceImpl implements PotatoDataSource {
  PotatoDataSourceImpl({@required this.client});
  final Dio client;

  @override
  Future<Either<Exception, PotatoPriceList>> getPriceList() => _get('getPriceList');

  @override
  Future<Either<Exception, PotatoCatalog>> getCatalog() => _get('getCatalog');

  @override
  Future<Either<Exception, PotatoGoodPictureList>> getPictureList() => _get('getPictureList');

  Future<Either<Exception, T>> _get<T>(String q) async {
    final response = await client
        .get<Map<String, dynamic>>(
          _query(q),
          options: Options(
            headers: {
              'Authorization': 'Basic ${AppConfig.base64}',
              'Content-Type': 'application/json',
            },
          ),
        )
        .catchError((e) => throw ServerException());

    if (response.statusCode != 200) {
      throw ServerException();
    }

    return Right(_fromJson<T>(response.data));
  }
}

const _queries = {
  'getPriceList': r"query1...", // разные запросы
  'getCatalog': r"query2...", // разные запросы
  'getPictureList': r"query3...", // разные запросы
};

//
// Utilits
//

String _query(String q) => AppConfig.db.address + _queries[q];

final _factories = <Type, Function>{
  PotatoPriceList: (Map<String, dynamic> json) => PotatoPriceList.fromJson(json),
  PotatoCatalog: (Map<String, dynamic> json) => PotatoCatalog.fromJson(json),
  PotatoGoodPictureList: (Map<String, dynamic> json) => PotatoGoodPictureList.fromJson(json),
};

T _fromJson<T>(Map<String, dynamic> json) {
  return _factories[T](json) as T;
}