import 'package:flutter_test/flutter_test.dart';
import 'package:shared_preferences/shared_preferences.dart';
import 'package:tm_app/core/network/app_exceptions.dart';
import 'package:tm_app/core/network/network_manager.dart';
import 'package:tm_app/core/utils/result.dart';
import 'package:tm_app/data/repositories/company_ai_repository.dart';
import 'package:tm_app/data/repositories/home_repository.dart';
import 'package:tm_app/data/services/company_ai_service.dart';
import 'package:tm_app/data/services/home_service.dart';
import 'package:tm_app/data/services/liked_tenders_service.dart';
import 'package:tm_app/data/services/model/recommend_response/recommend_response.dart';
import 'package:tm_app/data/services/model/recommendation_item/recommendation_item.dart';
import 'package:tm_app/data/services/model/recommended_tenders_data/recommended_tenders_data.dart';
import 'package:tm_app/data/services/model/recommended_tenders_response/recommended_tenders_response.dart';
import 'package:tm_app/data/services/your_tenders_service.dart';
import 'package:tm_app/view_models/ai_recommendations_view_model.dart';

void main() {
  group('AiRecommendationsViewModel', () {
    test('falls back to legacy recommendations on HTTP 503', () async {
      final prefs = await _prefs();
      final companyRepository = _FakeCompanyAiRepository(
        prefs,
        results: [Result.error(ServerException('unavailable', 503))],
      );
      final homeRepository = _FakeHomeRepository(
        prefs,
        result: const Result.ok(
          RecommendedTendersResponse(
            succes: true,
            message: 'ok',
            error: null,
            data: RecommendedTendersData(tenders: [], metadata: null),
          ),
        ),
      );
      final viewModel = AiRecommendationsViewModel(
        companyAiRepository: companyRepository,
        homeRepository: homeRepository,
      );

      await viewModel.loadRecommendations();

      expect(viewModel.hasLoaded, isTrue);
      expect(viewModel.usingFallback, isTrue);
      expect(viewModel.errorMessage, isNull);
      expect(homeRepository.recommendedTendersCalls, 1);
    });

    test('keeps failed transient loads retryable for loadIfNeeded', () async {
      final prefs = await _prefs();
      final companyRepository = _FakeCompanyAiRepository(
        prefs,
        results: [
          Result.error(FetchDataException('network failed')),
          const Result.ok(
            RecommendResponse(
              data: [
                RecommendationItem(
                  rank: '1',
                  tenderId: 'tender-1',
                  analysis: 'Strong match',
                ),
              ],
              error: null,
              message: 'ok',
              success: true,
            ),
          ),
        ],
      );
      final viewModel = AiRecommendationsViewModel(
        companyAiRepository: companyRepository,
        homeRepository: _FakeHomeRepository(prefs),
      );

      await viewModel.loadRecommendations();
      await viewModel.loadIfNeeded();

      expect(companyRepository.recommendationCalls, 2);
      expect(viewModel.hasLoaded, isTrue);
      expect(viewModel.errorMessage, isNull);
      expect(viewModel.items.single.tenderId, 'tender-1');
    });

    test(
      'marks empty results as still learning after recent onboarding',
      () async {
        final prefs = await _prefs();
        final viewModel = AiRecommendationsViewModel(
          companyAiRepository: _FakeCompanyAiRepository(
            prefs,
            lastOnboardingStartedAt: DateTime.now().millisecondsSinceEpoch,
            results: [
              const Result.ok(
                RecommendResponse(
                  data: [],
                  error: null,
                  message: 'ok',
                  success: true,
                ),
              ),
            ],
          ),
          homeRepository: _FakeHomeRepository(prefs),
        );

        await viewModel.loadRecommendations();

        expect(viewModel.hasLoaded, isTrue);
        expect(viewModel.stillLearning, isTrue);
        expect(viewModel.isEmpty, isTrue);
      },
    );
  });
}

Future<SharedPreferences> _prefs() async {
  SharedPreferences.setMockInitialValues({});
  return SharedPreferences.getInstance();
}

class _FakeCompanyAiRepository extends CompanyAiRepository {
  _FakeCompanyAiRepository(
    SharedPreferences prefs, {
    required List<Result<RecommendResponse>> results,
    int? lastOnboardingStartedAt,
  }) : _results = results,
       _lastOnboardingStartedAt = lastOnboardingStartedAt,
       super(companyAiService: _UnusedCompanyAiService(prefs), prefs: prefs);

  final List<Result<RecommendResponse>> _results;
  final int? _lastOnboardingStartedAt;
  int recommendationCalls = 0;

  @override
  Future<Result<RecommendResponse>> getRecommendations() async {
    final index = recommendationCalls;
    recommendationCalls += 1;
    return _results[index];
  }

  @override
  int? lastOnboardingStartedAt() => _lastOnboardingStartedAt;
}

class _FakeHomeRepository extends HomeRepository {
  _FakeHomeRepository(
    SharedPreferences prefs, {
    this.result = const Result.ok(
      RecommendedTendersResponse(
        succes: true,
        message: 'ok',
        error: null,
        data: RecommendedTendersData(tenders: [], metadata: null),
      ),
    ),
  }) : super(
         homeService: HomeService(networkManager: NetworkManager(prefs)),
         yourTendersService: YourTendersService(
           networkManager: NetworkManager(prefs),
         ),
         likedTendersService: LikedTendersService(
           networkManager: NetworkManager(prefs),
         ),
       );

  final Result<RecommendedTendersResponse> result;
  int recommendedTendersCalls = 0;

  @override
  Future<Result<RecommendedTendersResponse>> getHomeRecommendedTenders({
    required int limit,
    required int offset,
  }) async {
    recommendedTendersCalls += 1;
    return result;
  }
}

class _UnusedCompanyAiService extends CompanyAiService {
  _UnusedCompanyAiService(SharedPreferences prefs)
    : super(networkManager: NetworkManager(prefs));
}