// Events
abstract class SupplierEvent extends Equatable {}

class LoadSupplier extends SupplierEvent {}
class CreateSupplier extends SupplierEvent {}
class UpdateSupplier extends SupplierEvent {}
class DeleteSupplier extends SupplierEvent {}

// States
abstract class SupplierState extends Equatable {}

class SupplierInitial extends SupplierState {}
class SupplierLoading extends SupplierState {}
class SupplierLoaded extends SupplierState {}
class SupplierError extends SupplierState {}

// BLoC
class SupplierBloc extends Bloc<SupplierEvent, SupplierState> {
  final SupplierRepository _repository;
  
  SupplierBloc({required SupplierRepository repository})
      : _repository = repository,
        super(SupplierInitial()) {
    on<LoadSupplier>(_onLoad);
    on<CreateSupplier>(_onCreate);
    on<UpdateSupplier>(_onUpdate);
    on<DeleteSupplier>(_onDelete);
  }
  
  Future<void> _onLoad(
    LoadSupplier event,
    Emitter<SupplierState> emit,
  ) async {
    emit(SupplierLoading());
    
    final result = await _repository.getSuppliers();
    
    result.fold(
      (failure) => emit(SupplierError(failure.message)),
      (data) => emit(SupplierLoaded(data)),
    );
  }
}

abstract class SupplierRepository {
  Future<Either<Failure, List<Supplier>>> getSuppliers();
  Future<Either<Failure, Supplier>> getSupplierById(String id);
  Future<Either<Failure, Supplier>> createSupplier(Supplier data);
  Future<Either<Failure, Supplier>> updateSupplier(String id, Supplier data);
  Future<Either<Failure, void>> deleteSupplier(String id);
}

class SupplierRepositoryImpl implements SupplierRepository {
  final SupplierApi _api;
  final SupplierLocalRepository _localRepo;
  
  @override
  Future<Either<Failure, List<Supplier>>> getSuppliers() async {
    try {
      // Try local first (offline-first)
      final local = await _localRepo.getSuppliers();
      
      // Sync with API in background
      final result = await _api.getSuppliers();
      result.fold(
        (failure) => null,
        (data) => _localRepo.saveSuppliers(data),
      );
      
      return Right(local.isNotEmpty ? local : result.getOrElse(() => []));
    } catch (e) {
      return Left(UnexpectedFailure(e.toString()));
    }
  }
}

GET /api/v1/suppliers/*
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 SupplierLocal {
  Id id = Isar.autoIncrement;
  
  @Index()
  String? supplierId;
  
  String? name;
  DateTime? createdAt;
  DateTime? updatedAt;
  DateTime? syncedAt;
  
  bool? isSynced;
  bool? isDeleted;
}

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

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

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

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

class SupplierPage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return BlocProvider(
      create: (context) => getIt<SupplierBloc>()..add(LoadSupplier()),
      child: Scaffold(
        appBar: AppBar(title: Text('Supplier Management')),
        body: BlocBuilder<SupplierBloc, SupplierState>(
          builder: (context, state) {
            if (state is SupplierLoading) {
              return Center(child: CircularProgressIndicator());
            }
            
            if (state is SupplierError) {
              return ErrorWidget(message: state.message);
            }
            
            if (state is SupplierLoaded) {
              return SupplierListView(items: state.items);
            }
            
            return SizedBox.shrink();
          },
        ),
        floatingActionButton: FloatingActionButton(
          onPressed: () => _navigateToCreate(context),
          child: Icon(Icons.add),
        ),
      ),
    );
  }
}

void main() {
  group('SupplierBloc', () {
    late SupplierBloc bloc;
    late MockSupplierRepository mockRepository;

    setUp(() {
      mockRepository = MockSupplierRepository();
      bloc = SupplierBloc(repository: mockRepository);
    });

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

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

    blocTest<SupplierBloc, SupplierState>(
      'emits [Loading, Loaded] when Load succeeds',
      build: () {
        when(() => mockRepository.getSuppliers()).thenAnswer(
          (_) async => Right([Supplier(id: '1', name: 'Test')]),
        );
        return bloc;
      },
      act: (bloc) => bloc.add(LoadSupplier()),
      expect: () => [
        SupplierLoading(),
        isA<SupplierLoaded>(),
      ],
    );
  });
}