part of 'data_service.dart';

extension DataServiceTraction on DataService {
  Future<void> fetchHadTraction({int offset = 0, int limit = 100}) async {
    await fetchTraction(
      hadOnly: true,
      offset: offset,
      limit: limit,
      append: offset > 0,
    );
  }

  Future<void> fetchTraction({
    bool hadOnly = false,
    int offset = 0,
    int limit = 50,
    String? locoClass,
    String? locoNumber,
    bool mileageFirst = true,
    bool append = false,
    Map<String, dynamic>? filters,
  }) async {
    _isTractionLoading = true;

    try {
      final params = StringBuffer('?limit=$limit&offset=$offset');
      if (hadOnly) params.write('&had_only=true');
      if (!mileageFirst) params.write('&mileage_first=false');

      final payload = <String, dynamic>{};
      if (locoClass != null && locoClass.isNotEmpty) {
        payload['class'] = locoClass;
      }
      if (locoNumber != null && locoNumber.isNotEmpty) {
        payload['number'] = locoNumber;
      }
      if (filters != null) {
        filters.forEach((key, value) {
          if (value == null) return;
          if (value is String && value.trim().isEmpty) return;
          payload[key] = value;
        });
      }

      final json = await api.post(
        '/locos/search/v2${params.toString()}',
        payload.isEmpty ? null : payload,
      );

      if (json is List) {
        final newItems = json.map((e) => LocoSummary.fromJson(e)).toList();
        _traction = append ? [..._traction, ...newItems] : newItems;
        _tractionHasMore = newItems.length >= limit - 1;
      } else {
        throw Exception('Unexpected traction response: $json');
      }
    } catch (e) {
      debugPrint('Failed to fetch traction: $e');
      if (!append) {
        _traction = [];
      }
      _tractionHasMore = false;
    } finally {
      _isTractionLoading = false;
      _notifyAsync();
    }
  }

  Future<List<LocoAttrVersion>> fetchLocoTimeline(int locoId) async {
    _isLocoTimelineLoading[locoId] = true;
    _notifyAsync();
    try {
      final json = await api.get('/loco/get-timeline/$locoId');
      final timeline = LocoAttrVersion.fromGroupedJson(json);
      _locoTimelines[locoId] = timeline;
      return timeline;
    } catch (e) {
      debugPrint('Failed to fetch loco timeline for $locoId: $e');
      _locoTimelines[locoId] = [];
      return [];
    } finally {
      _isLocoTimelineLoading[locoId] = false;
      _notifyAsync();
    }
  }

  Future<dynamic> createLoco(Map<String, dynamic> payload) async {
    try {
      final response = await api.put('/loco/new', payload);
      final locoClass = payload['class']?.toString();
      if (locoClass != null &&
          locoClass.isNotEmpty &&
          !_locoClasses.contains(locoClass)) {
        _locoClasses = [..._locoClasses, locoClass];
      }
      _notifyAsync();
      return response;
    } catch (e) {
      debugPrint('Failed to create loco: $e');
      rethrow;
    }
  }

  Future<List<String>> fetchClassList() async {
    if (_locoClasses.isNotEmpty) return _locoClasses;
    try {
      final json = await api.get('/loco/classlist');
      if (json is List) {
        _locoClasses = json.map((e) => e.toString()).toList();
        _notifyAsync();
      }
    } catch (e) {
      debugPrint('Failed to fetch class list: $e');
    }
    return _locoClasses;
  }
}