import 'dart:convert';import 'package:dio/dio.dart';
import '../../core/config.dart';

class BackendApi {
  final Dio _dio;

  BackendApi()
      : _dio = Dio(
          BaseOptions(
            baseUrl: AppConfig.backendBaseUrl,
            headers: const {
              'Accept': 'application/json',
            },
            contentType: Headers.jsonContentType,
            validateStatus: (s) => s != null && s < 500,
          ),
        );

  Future<Map<String, dynamic>> _post(Map<String, dynamic> body) async {
    Future<Response> sendJson(Map<String, dynamic> p) {
      final prev = _dio.options.contentType;
      _dio.options.contentType = Headers.jsonContentType;
      return _dio.post('', data: p).whenComplete(() {
        _dio.options.contentType = prev;
      });
    }

    Future<Response> sendForm(Map<String, dynamic> p) {
      final prev = _dio.options.contentType;
      _dio.options.contentType = Headers.formUrlEncodedContentType;
      final flat = p.map((k, v) => MapEntry(k, (v is Map || v is List) ? jsonEncode(v) : v));
      return _dio.post('', data: flat).whenComplete(() {
        _dio.options.contentType = prev;
      });
    }

    Map<String, dynamic>? map;
    Response? res;
    final payload = {...body};
    try {
      res = await sendJson(payload);
    } on DioException catch (e) {
      // Capture 5xx with body
      if (e.response != null) {
        res = e.response;
      } else {
        // ignore: avoid_print
        print('Backend request failed (JSON, no response). URL: ${_dio.options.baseUrl}, payload: $payload, error: $e');
        throw Exception('Backend request failed: $e');
      }
    }

    bool shouldFallbackToForm() {
      final sc = res?.statusCode;
      if (sc == 400) {
        try {
          final d = res?.data;
          if (d is Map && (d['error']?.toString().toLowerCase().contains('unknown action') ?? false)) {
            return true;
          }
        } catch (_) {}
      }
      return false;
    }

    if (shouldFallbackToForm()) {
      // ignore: avoid_print
      print('Retrying request as form-urlencoded due to unknown action (server likely expects \$_POST).');
      try {
        res = await sendForm(payload);
      } on DioException catch (e) {
        if (e.response != null) {
          res = e.response;
        } else {
          // ignore: avoid_print
          print('Backend request failed (FORM, no response). URL: ${_dio.options.baseUrl}, payload: $payload, error: $e');
          throw Exception('Backend request failed: $e');
        }
      }
    }

    if (res != null && res.data is Map) {
      map = res.data as Map<String, dynamic>;
    }
    if (res == null || res.statusCode != 200) {
      // ignore: avoid_print
      final sc = res?.statusCode;
      final data = res?.data;
      print('Backend HTTP ${sc}. URL: ${_dio.options.baseUrl}, payload: $payload, data: ${data}');
      if (map != null && map.containsKey('error')) {
        throw Exception('Backend HTTP ${sc}: ${map['error']}');
      }
      throw Exception('Backend HTTP ${sc}: ${data}');
    }
    if (map == null) {
      throw Exception('Backend: Unexpected response format');
    }
    if (map['ok'] != true) {
      // ignore: avoid_print
      print('Backend logical error. URL: ${_dio.options.baseUrl}, payload: $payload, data: $map');
      throw Exception('Backend responded with error: ${map['error']}');
    }
    return map;
  }

  Future<List<Map<String, dynamic>>> getMovies(
      {String? status, String? q, int offset = 0, int limit = 50}) async {
    final map = await _post({
      'action': 'get_list',
      'type': 'movie',
      if (status != null) 'status': status,
      if (q != null && q.isNotEmpty) 'q': q,
      'offset': offset,
      'limit': limit,
    });
    return (map['items'] as List).cast<Map<String, dynamic>>();
  }

  Future<void> setStatus({
    required String type, // 'movie' | 'episode'
    required int refId,
    required String status, // 'Init' | 'Progress' | 'Done'
  }) async {
    await _post({
      'action': 'set_status',
      'type': type,
      'ref_id': refId,
      'status': status,
    });
  }

  Future<void> upsertMovie(Map<String, dynamic> tmdbJson) async {
    await _post({
      'action': 'upsert_movie',
      'tmdb': tmdbJson,
    });
  }

  Future<List<Map<String, dynamic>>> getEpisodes({
    String? status,
    String? q,
    int offset = 0,
    int limit = 5000,
  }) async {
    final map = await _post({
      'action': 'get_list',
      'type': 'episode',
      if (status != null) 'status': status,
      if (q != null && q.isNotEmpty) 'q': q,
      'offset': offset,
      'limit': limit,
    });
    return (map['items'] as List).cast<Map<String, dynamic>>();
  }

  Future<void> upsertShow(Map<String, dynamic> tmdbJson) async {
    await _post({'action': 'upsert_show', 'tmdb': tmdbJson});
  }

  Future<int> upsertSeason(int showId, Map<String, dynamic> seasonJson) async {
    final map = await _post(
        {'action': 'upsert_season', 'show_id': showId, 'tmdb': seasonJson});
    return (map['id'] as num).toInt();
  }

  Future<int> upsertEpisode(
      int seasonId, Map<String, dynamic> episodeJson) async {
    final map = await _post({
      'action': 'upsert_episode',
      'season_id': seasonId,
      'tmdb': episodeJson
    });
    return (map['id'] as num).toInt();
  }

  Future<int?> getShowDbIdByTmdbId(int tmdbId) async {
    final map = await _post({'action': 'get_show_by_tmdb', 'tmdb_id': tmdbId});
    final v = map['id'];
    return v == null ? null : (v as num).toInt();
  }
}