【Flutter】Architecture case study【日本語訳】

<div class="joplin-editable"><pre class="joplin-source" data-joplin-language="plaintext" data-joplin-source-open="```plaintext
" data-joplin-source-close="
```">lib
|____ui
| |____core
| | |____ui
| | | |____<shared widgets>
| | |____themes
| |____<FEATURE NAME>
| | |____view_model
| | | |_____<view_model class>.dart
| | |____widgets
| | | |____<feature name>_screen.dart
| | | |____<other widgets>
|____domain
| |____models
| | |____<model name>.dart
|____data
| |____repositories
| | |____<repository class>.dart
| |____services
| | |____<service class>.dart
| |____model
| | |____<api model class>.dart
|____config
|____utils
|____routing
|____main_staging.dart
|____main_development.dart
|____main.dart

test
|____data
|____domain
|____ui
|____utils

testing
|____fakes
|____models

class HomeViewModel {
  HomeViewModel({
    required BookingRepository bookingRepository,
    required UserRepository userRepository,
  })  : _bookingRepository = bookingRepository,
        _userRepository = userRepository;

  final BookingRepository _bookingRepository;
  final UserRepository _userRepository;

  // その他のロジック
}

class HomeViewModel {
  HomeViewModel({
    required BookingRepository bookingRepository,
    required UserRepository userRepository,
  })  : _bookingRepository = bookingRepository,
        _userRepository = userRepository;

  final BookingRepository _bookingRepository;
  final UserRepository _userRepository;

  User? _user;
  User? get user => _user;

  List<BookingSummary> _bookings = [];
  UnmodifiableListView<BookingSummary> get bookings => UnmodifiableListView(_bookings);

  // その他のロジック
}

@freezed
class User with _$User {
  const factory User({
    required String name,
    required String picture,
  }) = _User;

  factory User.fromJson(Map<String, Object?> json) => _$UserFromJson(json);
}

class HomeViewModel extends ChangeNotifier {
  HomeViewModel({
    required BookingRepository bookingRepository,
    required UserRepository userRepository,
  })  : _bookingRepository = bookingRepository,
        _userRepository = userRepository;

  final BookingRepository _bookingRepository;
  final UserRepository _userRepository;

  User? _user;
  User? get user => _user;

  List<BookingSummary> _bookings = [];
  List<BookingSummary> get bookings => _bookings;

  Future<Result> _load() async {
    try {
      final userResult = await _userRepository.getUser();
      switch (userResult) {
           case Ok<User>():
               _user = userResult.value;
               _log.fine('Loaded user');
           case Error<User>():
           // エラー処理
               _log.warning('Failed to load user', userResult.error);
      }
      return userResult;
    } finally {
      notifyListeners();
    }
  }

}

class HomeScreen extends StatelessWidget {
  const HomeScreen({super.key, required this.viewModel});

  final HomeViewModel viewModel;

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      // ...
    );
  }
}

class HomeScreen extends StatelessWidget {
  const HomeScreen({super.key, required this.viewModel});

  final HomeViewModel viewModel;

  @override
  Widget build(BuildContext context) {
    // ...
  }
}

@override
Widget build(BuildContext context) {
  return Scaffold(
    // Some code was removed for brevity.
    body: SafeArea(
      child: ListenableBuilder(
        listenable: viewModel,
        builder: (context, _) {
          return CustomScrollView(
            slivers: [
              SliverToBoxAdapter(...),
              SliverList.builder(
                itemCount: viewModel.bookings.length,
                itemBuilder: (_, index) => _Booking(
                  key: ValueKey(viewModel.bookings[index].id),
                  booking:viewModel.bookings[index],
                  onTap: () => context.push(
                    Routes.bookingWithId(
                      viewModel.bookings[index].id)),
                  onDismissed: (_) => viewModel.deleteBooking.execute(
                       viewModel.bookings[index].id,
                     ),
                ),
              ),
            ],
          );
        },
      ),
    ),
  );
}

@override
Widget build(BuildContext context) {
  return Scaffold(
    body: SafeArea(
      child: ListenableBuilder(
        listenable: viewModel,
        builder: (context, _) {
          return CustomScrollView(
            slivers: [
              SliverToBoxAdapter(...),
              SliverList.builder(
                itemCount: viewModel.bookings.length,
                itemBuilder: (_, index) => _Booking(
                  key: ValueKey(viewModel.bookings[index].id),
                  booking: viewModel.bookings[index],
                  onTap: () => context.push(Routes.bookingWithId(viewModel.bookings[index].id)),
                  onDismissed: (_) => viewModel.deleteBooking.execute(viewModel.bookings[index].id),
                ),
              ),
            ],
          );
        },
      ),
    ),
  );
}

SliverList.builder(
  itemCount: widget.viewModel.bookings.length,
  itemBuilder: (_, index) => _Booking(
    key: ValueKey(viewModel.bookings[index].id),
    booking: viewModel.bookings[index],
    onTap: () => context.push(
      Routes.bookingWithId(viewModel.bookings[index].id)
    ),
    onDismissed: (_) =>
      viewModel.deleteBooking.execute(widget.viewModel.bookings[index].id),
  ),
),

Future<Result<void>> _deleteBooking(int id) async {
  try {
    final resultDelete = await _bookingRepository.delete(id);
    switch (resultDelete) {
      case Ok<void>():
        _log.fine('Deleted booking $id');
      case Error<void>():
        _log.warning('Failed to delete booking $id', resultDelete.error);
        return resultDelete;
    }

    // Some code was omitted for brevity.
    // final  resultLoadBookings = ...;

    return resultLoadBookings;
  } finally {
    notifyListeners();
  }
}

abstract class Command<T> extends ChangeNotifier {
  Command();

  bool running = false;
  Result<T>? _result;

  /// true if action completed with error
  bool get error => _result is Error;

  /// true if action completed successfully
  bool get completed => _result is Ok;

  /// Internal execute implementation
  Future<void> _execute(action) async {
    if (_running) return;

    // Emit running state - e.g. button shows loading state
    _running = true;
    _result = null;
    notifyListeners();

    try {
      _result = await action();
    } finally {
      _running = false;
      notifyListeners();
    }
  }
}

class HomeViewModel extends ChangeNotifier {
  HomeViewModel({
   required BookingRepository bookingRepository,
   required UserRepository userRepository,
  }) : _bookingRepository = bookingRepository,
      _userRepository = userRepository {
    // Load required data when this screen is built.
    load = Command0(_load)..execute();
    deleteBooking = Command1(_deleteBooking);
  }

  final BookingRepository _bookingRepository;
  final UserRepository _userRepository;

  late Command0 load;
  late Command1<void, int> deleteBooking;

  User? _user;
  User? get user => _user;

  List<BookingSummary> _bookings = [];
  List<BookingSummary> get bookings => _bookings;

  Future<Result> _load() async {
    // ...
  }

  Future<Result<void>> _deleteBooking(int id) async {
    // ...
  }

  // ...
}

// ...
child: ListenableBuilder(
  listenable: viewModel.load,
  builder: (context, child) {
    if (viewModel.load.running) {
      return const Center(child: CircularProgressIndicator());
    }

    if (viewModel.load.error) {
      return ErrorIndicator(
        title: AppLocalization.of(context).errorWhileLoadingHome,
        label: AppLocalization.of(context).tryAgain,
        onPressed: viewModel.load.execute,
      );
    }

    // The command has completed without error.
    // Return the main view widget.
    return child!;
  },
),
...

class ApiClient {
  // Some code omitted for demo purposes.

  Future<Result<List<ContinentApiModel>>> getContinents() async { /* ... */ }

  Future<Result<List<DestinationApiModel>>> getDestinations() async { /* ... */ }

  Future<Result<List<ActivityApiModel>>> getActivityByDestination(String ref) async { /* ... */ }

  Future<Result<List<BookingApiModel>>> getBookings() async { /* ... */ }

  Future<Result<BookingApiModel>> getBooking(int id) async { /* ... */ }

  Future<Result<BookingApiModel>> postBooking(BookingApiModel booking) async { /* ... */ }

  Future<Result<void>> deleteBooking(int id) async { /* ... */ }

  Future<Result<UserApiModel>> getUser() async { /* ... */ }
}

class BookingRepositoryRemote implements BookingRepository {
  BookingRepositoryRemote({
    required ApiClient apiClient,
  }) : _apiClient = apiClient;

  final ApiClient _apiClient;
  List<Destination>? _cachedDestinations;

  Future<Result<void>> createBooking(Booking booking) async {...}
  Future<Result<Booking>> getBooking(int id) async {...}
  Future<Result<List<BookingSummary>>> getBookingsList() async {...}
  Future<Result<void>> delete(int id) async {...}
}

 // This method was edited for brevity.
Future<Result<Booking>> getBooking(int id) async {
  try {
    // Get the booking by ID from server.
    final resultBooking = await _apiClient.getBooking(id);
    if (resultBooking is Error<BookingApiModel>) {
      return Result.error(resultBooking.error);
    }
    final booking = resultBooking.asOk.value;

    final destination = _apiClient.getDestination(booking.destinationRef);
    final activities = _apiClient.getActivitiesForBooking(
            booking.activitiesRef);

    return Result.ok(
      Booking(
        startDate: booking.startDate,
        endDate: booking.endDate,
        destination: destination,
        activity: activities,
      ),
    );
  } on Exception catch (e) {
    return Result.error(e);
  }
}

Future<Result<void>> delete(int id) async {
  try {
    return _apiClient.deleteBooking(id);
  } on Exception catch (e) {
    return Result.error(e);
  }
}

class MyRepository {
  MyRepository({required MyService myService})
          : _myService = myService;

  late final MyService _myService;
}

runApp(
  MultiProvider(
    providers: [
      Provider(create: (context) => AuthApiClient()),
      Provider(create: (context) => ApiClient()),
      Provider(create: (context) => SharedPreferencesService()),
      ChangeNotifierProvider(
        create: (context) => AuthRepositoryRemote(
          authApiClient: context.read(),
          apiClient: context.read(),
          sharedPreferencesService: context.read(),
        ) as AuthRepository,
      ),
      Provider(create: (context) =>
        DestinationRepositoryRemote(
          apiClient: context.read(),
        ) as DestinationRepository,
      ),
      Provider(create: (context) =>
        ContinentRepositoryRemote(
          apiClient: context.read(),
        ) as ContinentRepository,
      ),
      // In the Compass app, additional service and repository providers live here.
    ],
    child: const MainApp(),
  ),
);

 // This code was modified for demo purposes.
GoRouter router(
  AuthRepository authRepository,
) =>
    GoRouter(
      initialLocation: Routes.home,
      debugLogDiagnostics: true,
      redirect: _redirect,
      refreshListenable: authRepository,
      routes: [
        GoRoute(
          path: Routes.login,
          builder: (context, state) {
            return LoginScreen(
              viewModel: LoginViewModel(
                authRepository: context.read(),
              ),
            );
          },
        ),
        GoRoute(
          path: Routes.home,
          builder: (context, state) {
            final viewModel = HomeViewModel(
              bookingRepository: context.read(),
            );
            return HomeScreen(viewModel: viewModel);
          },
          routes: [
            // ...
          ],
        ),
      ],
    );

class HomeViewModel extends ChangeNotifier {
  HomeViewModel({
    required BookingRepository bookingRepository,
    required UserRepository userRepository,
  })  : _bookingRepository = bookingRepository,
        _userRepository = userRepository;

  final BookingRepository _bookingRepository;
  final UserRepository _userRepository;

  // ...
}

void main() {
  group('HomeViewModel tests', () {
    test('Load bookings', () {
      // HomeViewModel._load is called in the constructor of HomeViewModel.
      final viewModel = HomeViewModel(
        bookingRepository: FakeBookingRepository()
          ..createBooking(kBooking),
        userRepository: FakeUserRepository(),
      );

      expect(viewModel.bookings.isNotEmpty, true);
    });
  });
}

class FakeBookingRepository implements BookingRepository {
  List<Booking> bookings = List.empty(growable: true);

  @override
  Future<Result<void>> createBooking(Booking booking) async {
    bookings.add(booking);
    return Result.ok(null);
  }
  // ...
}

void main() {
  group('HomeScreen tests', () {
    late HomeViewModel viewModel;
    late MockGoRouter goRouter;
    late FakeBookingRepository bookingRepository;

    setUp(() {
      bookingRepository = FakeBookingRepository()
        ..createBooking(kBooking);
      viewModel = HomeViewModel(
        bookingRepository: bookingRepository,
        userRepository: FakeUserRepository(),
      );
      goRouter = MockGoRouter();
      when(() => goRouter.push(any()))
          .thenAnswer((_) => Future.value(null));
    });

    // ...
  });
}

void main() {
  group('HomeScreen tests', () {
    late HomeViewModel viewModel;
    late MockGoRouter goRouter;
    late FakeBookingRepository bookingRepository;

    setUp(
      // ...
    );

    void loadWidget(WidgetTester tester) async {
      await testApp(
        tester,
        ChangeNotifierProvider.value(
          value: FakeAuthRepository() as AuthRepository,
          child: Provider.value(
            value: FakeItineraryConfigRepository() as ItineraryConfigRepository,
            child: HomeScreen(viewModel: viewModel),
          ),
        ),
        goRouter: goRouter,
      );
    }

    // ...
  });
}

void testApp(
  WidgetTester tester,
  Widget body, {
  GoRouter? goRouter,
}) async {
  tester.view.devicePixelRatio = 1.0;
  await tester.binding.setSurfaceSize(const Size(1200, 800));
  await mockNetworkImages(() async {
    await tester.pumpWidget(
      MaterialApp(
        localizationsDelegates: [
          GlobalWidgetsLocalizations.delegate,
          GlobalMaterialLocalizations.delegate,
          AppLocalizationDelegate(),
        ],
        theme: AppTheme.lightTheme,
        home: InheritedGoRouter(
          goRouter: goRouter ?? MockGoRouter(),
          child: Scaffold(
            body: body,
          ),
        ),
      ),
    );
  });
}

void main() {
  group('BookingRepositoryRemote tests', () {
    late BookingRepository bookingRepository;
    late FakeApiClient fakeApiClient;

    setUp(() {
      fakeApiClient = FakeApiClient();
      bookingRepository = BookingRepositoryRemote(
        apiClient: fakeApiClient,
      );
    });

    test('should get booking', () async {
      final result = await bookingRepository.getBooking(0);
      final booking = result.asOk.value;
      expect(booking, kBooking);
    });
  });
}