// Events
abstract class DebtEvent extends Equatable {}

class LoadDebt extends DebtEvent {}
class CreateDebt extends DebtEvent {}
class UpdateDebt extends DebtEvent {}
class DeleteDebt extends DebtEvent {}

// States
abstract class DebtState extends Equatable {}

class DebtInitial extends DebtState {}
class DebtLoading extends DebtState {}
class DebtLoaded extends DebtState {}
class DebtError extends DebtState {}

// BLoC
class DebtBloc extends Bloc<DebtEvent, DebtState> {
  final DebtRepository _repository;
  
  DebtBloc({required DebtRepository repository})
      : _repository = repository,
        super(DebtInitial()) {
    on<LoadDebt>(_onLoad);
    on<CreateDebt>(_onCreate);
    on<UpdateDebt>(_onUpdate);
    on<DeleteDebt>(_onDelete);
  }
  
  Future<void> _onLoad(
    LoadDebt event,
    Emitter<DebtState> emit,
  ) async {
    emit(DebtLoading());
    
    final result = await _repository.getDebts();
    
    result.fold(
      (failure) => emit(DebtError(failure.message)),
      (data) => emit(DebtLoaded(data)),
    );
  }
}

abstract class DebtRepository {
  Future<Either<Failure, List<Debt>>> getDebts();
  Future<Either<Failure, Debt>> getDebtById(String id);
  Future<Either<Failure, Debt>> createDebt(Debt data);
  Future<Either<Failure, Debt>> updateDebt(String id, Debt data);
  Future<Either<Failure, void>> deleteDebt(String id);
}

class DebtRepositoryImpl implements DebtRepository {
  final DebtApi _api;
  final DebtLocalRepository _localRepo;
  
  @override
  Future<Either<Failure, List<Debt>>> getDebts() async {
    try {
      // Try local first (offline-first)
      final local = await _localRepo.getDebts();
      
      // Sync with API in background
      final result = await _api.getDebts();
      result.fold(
        (failure) => null,
        (data) => _localRepo.saveDebts(data),
      );
      
      return Right(local.isNotEmpty ? local : result.getOrElse(() => []));
    } catch (e) {
      return Left(UnexpectedFailure(e.toString()));
    }
  }
}

GET /api/v1/debts/*
Authorization: Bearer {access_token}

{
  "success": true,
  "data": [
    {
      "id": "123",
      "name": "Example",
      "created_at": "2024-10-14T10:00:00Z"
    }
  ],
  "pagination": {
    "page": 1,
    "limit": 20,
    "total": 100
  }
}

@collection
class DebtLocal {
  Id id = Isar.autoIncrement;
  
  @Index()
  String? debtId;
  
  String? name;
  DateTime? createdAt;
  DateTime? updatedAt;
  DateTime? syncedAt;
  
  bool? isSynced;
  bool? isDeleted;
}

// Get all
final items = await isar.debtLocals.where().findAll();

// Get by ID
final item = await isar.debtLocals
    .filter()
    .debtIdEqualTo(id)
    .findFirst();

// Search
final results = await isar.debtLocals
    .filter()
    .nameContains(query, caseSensitive: false)
    .findAll();

// Get unsynced
final unsynced = await isar.debtLocals
    .filter()
    .isSyncedEqualTo(false)
    .findAll();

class DebtPage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return BlocProvider(
      create: (context) => getIt<DebtBloc>()..add(LoadDebt()),
      child: Scaffold(
        appBar: AppBar(title: Text('Debt Management')),
        body: BlocBuilder<DebtBloc, DebtState>(
          builder: (context, state) {
            if (state is DebtLoading) {
              return Center(child: CircularProgressIndicator());
            }
            
            if (state is DebtError) {
              return ErrorWidget(message: state.message);
            }
            
            if (state is DebtLoaded) {
              return DebtListView(items: state.items);
            }
            
            return SizedBox.shrink();
          },
        ),
        floatingActionButton: FloatingActionButton(
          onPressed: () => _navigateToCreate(context),
          child: Icon(Icons.add),
        ),
      ),
    );
  }
}

void main() {
  group('DebtBloc', () {
    late DebtBloc bloc;
    late MockDebtRepository mockRepository;

    setUp(() {
      mockRepository = MockDebtRepository();
      bloc = DebtBloc(repository: mockRepository);
    });

    tearDown(() {
      bloc.close();
    });

    test('initial state is DebtInitial', () {
      expect(bloc.state, equals(DebtInitial()));
    });

    blocTest<DebtBloc, DebtState>(
      'emits [Loading, Loaded] when Load succeeds',
      build: () {
        when(() => mockRepository.getDebts()).thenAnswer(
          (_) async => Right([Debt(id: '1', name: 'Test')]),
        );
        return bloc;
      },
      act: (bloc) => bloc.add(LoadDebt()),
      expect: () => [
        DebtLoading(),
        isA<DebtLoaded>(),
      ],
    );
  });
}