doc(arch): add fully featured example

2022-11-08 20:09:18 -05:00
parent db67491876
commit 6602db215f
109 changed files with 4499 additions and 29 deletions
@@ -0,0 +1,25 @@
+// Copyright (C) 2022 WYATT GROUP
+// Please see the AUTHORS file for details.
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+import 'package:architecture_example/presentation/features/albums/state_management/albums_screen.dart';
+import 'package:flutter/material.dart';
+
+class Albums extends StatelessWidget {
+  const Albums({super.key});
+
+  @override
+  Widget build(BuildContext context) => const AlbumsScreen();
+}
@@ -0,0 +1,94 @@
+// Copyright (C) 2022 WYATT GROUP
+// Please see the AUTHORS file for details.
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+import 'package:architecture_example/core/enums/fetch_status.dart';
+import 'package:architecture_example/domain/entities/album.dart';
+import 'package:architecture_example/domain/usecases/photos/params/query_parameters.dart';
+import 'package:architecture_example/domain/usecases/photos/retrieve_all_albums.dart';
+import 'package:bloc_concurrency/bloc_concurrency.dart';
+import 'package:equatable/equatable.dart';
+import 'package:flutter_bloc/flutter_bloc.dart';
+import 'package:stream_transform/stream_transform.dart';
+
+part 'album_event.dart';
+part 'album_state.dart';
+
+const _albumLimit = 20;
+const throttleDuration = Duration(milliseconds: 100);
+
+EventTransformer<E> throttleDroppable<E>(Duration duration) =>
+    (events, mapper) => droppable<E>().call(events.throttle(duration), mapper);
+
+class AlbumBloc extends Bloc<AlbumEvent, AlbumState> {
+  final RetrieveAllAlbums _retrieveAllAlbums;
+
+  AlbumBloc(this._retrieveAllAlbums) : super(const AlbumState()) {
+    on<AlbumFetched>(
+      _onAlbumFetched,
+      transformer: throttleDroppable(throttleDuration),
+    );
+  }
+
+  Future<void> _onAlbumFetched(
+    AlbumFetched event,
+    Emitter<AlbumState> emit,
+  ) async {
+    if (state.hasReachedMax) {
+      return;
+    }
+    if (state.status == FetchStatus.initial) {
+      final albums =
+          await _retrieveAllAlbums.call(QueryParameters(0, _albumLimit));
+      return emit(
+        albums.fold(
+          (value) => state.copyWith(
+            status: FetchStatus.success,
+            albums: value,
+            hasReachedMax: false,
+          ),
+          (error) => state.copyWith(
+            status: FetchStatus.failure,
+            albums: [],
+            hasReachedMax: false,
+          ),
+        ),
+      );
+    }
+    final albums = await _retrieveAllAlbums
+        .call(QueryParameters(state.albums.length, _albumLimit));
+    return emit(
+      albums.fold(
+        (value) {
+          if (value.isEmpty) {
+            return state.copyWith(
+              hasReachedMax: true,
+            );
+          }
+          return state.copyWith(
+            status: FetchStatus.success,
+            albums: List.of(state.albums)..addAll(value),
+            hasReachedMax: false,
+          );
+        },
+        (error) => state.copyWith(
+          status: FetchStatus.failure,
+          albums: List.of(state.albums),
+          hasReachedMax: false,
+        ),
+      ),
+    );
+  }
+}
@@ -0,0 +1,26 @@
+// Copyright (C) 2022 WYATT GROUP
+// Please see the AUTHORS file for details.
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+part of 'album_bloc.dart';
+
+abstract class AlbumEvent extends Equatable {
+  const AlbumEvent();
+
+  @override
+  List<Object> get props => [];
+}
+
+class AlbumFetched extends AlbumEvent {}
@@ -0,0 +1,43 @@
+// Copyright (C) 2022 WYATT GROUP
+// Please see the AUTHORS file for details.
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+part of 'album_bloc.dart';
+
+class AlbumState extends Equatable {
+  const AlbumState({
+    this.status = FetchStatus.initial,
+    this.albums = const <Album>[],
+    this.hasReachedMax = false,
+  });
+
+  final FetchStatus status;
+  final List<Album> albums;
+  final bool hasReachedMax;
+
+  AlbumState copyWith({
+    FetchStatus? status,
+    List<Album>? albums,
+    bool? hasReachedMax,
+  }) =>
+      AlbumState(
+        status: status ?? this.status,
+        albums: albums ?? this.albums,
+        hasReachedMax: hasReachedMax ?? this.hasReachedMax,
+      );
+
+  @override
+  List<Object> get props => [status, albums, hasReachedMax];
+}
@@ -0,0 +1,58 @@
+// Copyright (C) 2022 WYATT GROUP
+// Please see the AUTHORS file for details.
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+import 'package:architecture_example/core/enums/fetch_status.dart';
+import 'package:architecture_example/domain/repositories/photo_repository.dart';
+import 'package:architecture_example/domain/usecases/photos/retrieve_all_albums.dart';
+import 'package:architecture_example/presentation/features/albums/blocs/album/album_bloc.dart';
+import 'package:architecture_example/presentation/features/albums/state_management/albums_wrapper_widget.dart';
+import 'package:architecture_example/presentation/features/albums/state_management/widgets/albums_list.dart';
+import 'package:flutter/material.dart';
+import 'package:wyatt_bloc_helper/wyatt_bloc_helper.dart';
+
+class AlbumsScreen extends BlocScreen<AlbumBloc, AlbumEvent, AlbumState> {
+  const AlbumsScreen({super.key});
+
+  @override
+  AlbumBloc create(BuildContext context) =>
+      AlbumBloc(RetrieveAllAlbums(repo<PhotoRepository>(context)));
+
+  @override
+  AlbumBloc init(BuildContext context, AlbumBloc bloc) =>
+      bloc..add(AlbumFetched());
+
+  @override
+  Widget onWrap(BuildContext context, Widget child) => AlbumsWrapperWidget(
+        child: child,
+      );
+
+  @override
+  Widget onBuild(BuildContext context, AlbumState state) {
+    switch (state.status) {
+      case FetchStatus.initial:
+        return const Center(child: CircularProgressIndicator());
+      case FetchStatus.failure:
+        return const Center(
+          child: Text('failed to fetch albums'),
+        );
+      case FetchStatus.success:
+        return AlbumsList(
+          albums: state.albums,
+          hasReachedMax: state.hasReachedMax,
+        );
+    }
+  }
+}
@@ -0,0 +1,31 @@
+// Copyright (C) 2022 WYATT GROUP
+// Please see the AUTHORS file for details.
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+import 'package:flutter/material.dart';
+
+class AlbumsWrapperWidget extends StatelessWidget {
+  const AlbumsWrapperWidget({required this.child, super.key});
+
+  final Widget child;
+
+  @override
+  Widget build(BuildContext context) => Scaffold(
+        appBar: AppBar(
+          title: const Text('Albums'),
+        ),
+        body: child,
+      );
+}
@@ -0,0 +1,77 @@
+// Copyright (C) 2022 WYATT GROUP
+// Please see the AUTHORS file for details.
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+import 'package:architecture_example/domain/entities/album.dart';
+import 'package:architecture_example/presentation/features/albums/blocs/album/album_bloc.dart';
+import 'package:architecture_example/presentation/features/albums/state_management/widgets/albums_list_item.dart';
+import 'package:architecture_example/presentation/shared/widgets/bottom_loader.dart';
+import 'package:flutter/material.dart';
+import 'package:flutter_bloc/flutter_bloc.dart';
+
+class AlbumsList extends StatefulWidget {
+  const AlbumsList(
+      {required this.albums, required this.hasReachedMax, super.key,});
+
+  final List<Album> albums;
+  final bool hasReachedMax;
+
+  @override
+  State<AlbumsList> createState() => _AlbumsListState();
+}
+
+class _AlbumsListState extends State<AlbumsList> {
+  final _scrollController = ScrollController();
+
+  @override
+  void initState() {
+    super.initState();
+    _scrollController.addListener(_onScroll);
+  }
+
+  @override
+  void dispose() {
+    _scrollController
+      ..removeListener(_onScroll)
+      ..dispose();
+    super.dispose();
+  }
+
+  void _onScroll() {
+    if (_isBottom) {
+      context.read<AlbumBloc>().add(AlbumFetched());
+    }
+  }
+
+  bool get _isBottom {
+    if (!_scrollController.hasClients) {
+      return false;
+    }
+    final maxScroll = _scrollController.position.maxScrollExtent;
+    final currentScroll = _scrollController.offset;
+    return currentScroll >= (maxScroll * 0.9);
+  }
+
+  @override
+  Widget build(BuildContext context) => ListView.builder(
+        itemBuilder: (context, index) => index >= widget.albums.length
+            ? const BottomLoader()
+            : AlbumsListItem(album: widget.albums[index]),
+        itemCount: widget.hasReachedMax
+            ? widget.albums.length
+            : widget.albums.length + 1,
+        controller: _scrollController,
+      );
+}
@@ -0,0 +1,37 @@
+// Copyright (C) 2022 WYATT GROUP
+// Please see the AUTHORS file for details.
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+import 'package:architecture_example/domain/entities/album.dart';
+import 'package:architecture_example/presentation/features/photos/photos.dart';
+import 'package:flutter/material.dart';
+
+class AlbumsListItem extends StatelessWidget {
+  const AlbumsListItem({required this.album, super.key});
+
+  final Album album;
+
+  @override
+  Widget build(BuildContext context) => ListTile(
+        leading: Text('${album.id}'),
+        title: Text(album.title),
+        dense: true,
+        onTap: () => Navigator.of(context).push(
+          MaterialPageRoute<void>(
+            builder: (context) => Photos(albumId: album.id),
+          ),
+        ),
+      );
+}
@@ -0,0 +1,47 @@
+// Copyright (C) 2022 WYATT GROUP
+// Please see the AUTHORS file for details.
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+import 'package:architecture_example/core/dependency_injection/get_it.dart';
+import 'package:architecture_example/data/repositories/photo_repository_impl.dart';
+import 'package:architecture_example/domain/data_sources/local/favorite_local_data_source.dart';
+import 'package:architecture_example/domain/data_sources/remote/album_remote_data_source.dart';
+import 'package:architecture_example/domain/data_sources/remote/photo_remote_data_source.dart';
+import 'package:architecture_example/domain/repositories/photo_repository.dart';
+import 'package:architecture_example/presentation/features/albums/albums.dart';
+import 'package:flutter/material.dart';
+import 'package:flutter_bloc/flutter_bloc.dart';
+
+class App extends StatelessWidget {
+  const App({super.key});
+
+  @override
+  Widget build(BuildContext context) => MultiRepositoryProvider(
+        providers: [
+          RepositoryProvider<PhotoRepository>(
+            create: (_) => PhotoRepositoryImpl(
+              getIt<PhotoRemoteDataSource>(),
+              getIt<AlbumRemoteDataSource>(),
+              getIt<FavoriteLocalDataSource>(),
+            ),
+          ),
+        ],
+        child: const MaterialApp(
+          title: 'Demo',
+          debugShowCheckedModeBanner: false,
+          home: Albums(),
+        ),
+      );
+}
@@ -0,0 +1,79 @@
+// ignore_for_file: public_member_api_docs, sort_constructors_first
+// Copyright (C) 2022 WYATT GROUP
+// Please see the AUTHORS file for details.
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+import 'dart:async';
+
+import 'package:architecture_example/domain/entities/photo.dart';
+import 'package:architecture_example/domain/usecases/photos/add_photo_to_favorites.dart';
+import 'package:architecture_example/domain/usecases/photos/check_if_photo_is_in_favorites.dart';
+import 'package:architecture_example/domain/usecases/photos/display_photo.dart';
+import 'package:architecture_example/domain/usecases/photos/remove_photo_from_favorites.dart';
+import 'package:equatable/equatable.dart';
+import 'package:flutter_bloc/flutter_bloc.dart';
+
+part 'photo_details_state.dart';
+
+class PhotoDetailsCubit extends Cubit<PhotoDetailsState> {
+  final DisplayPhoto _displayPhoto;
+  final CheckIfPhotoIsInFavorites _checkIfPhotoIsInFavorites;
+  final AddPhotoToFavorites _addPhotoToFavorites;
+  final RemovePhotoFromFavorites _removePhotoFromFavorites;
+
+  PhotoDetailsCubit(
+    this._displayPhoto,
+    this._checkIfPhotoIsInFavorites,
+    this._addPhotoToFavorites,
+    this._removePhotoFromFavorites,
+  ) : super(PhotoDetailsInitial());
+
+  FutureOr<void> load(int photoId) async {
+    final photo = await _displayPhoto.call(photoId);
+    final isFavorite = await _checkIfPhotoIsInFavorites.call(photoId);
+
+    emit(
+      photo.fold(
+        (value) => PhotoDetailsSuccess(
+          value,
+          isFavorite: isFavorite.fold((value) => value, (error) => false),
+        ),
+        (error) => PhotoDetailsFailure(error.toString()),
+      ),
+    );
+  }
+
+  FutureOr<void> addToFavorites() async {
+    if (state is! PhotoDetailsSuccess) {
+      return;
+    }
+    final actualState = state as PhotoDetailsSuccess;
+    final response = await _addPhotoToFavorites.call(actualState.photo);
+    if (response.isOk) {
+      emit(PhotoDetailsSuccess(actualState.photo, isFavorite: true));
+    }
+  }
+
+  FutureOr<void> removeFromFavorites() async {
+    if (state is! PhotoDetailsSuccess) {
+      return;
+    }
+    final actualState = state as PhotoDetailsSuccess;
+    final response = await _removePhotoFromFavorites.call(actualState.photo.id);
+    if (response.isOk) {
+      emit(PhotoDetailsSuccess(actualState.photo, isFavorite: false));
+    }
+  }
+}
@@ -0,0 +1,45 @@
+// Copyright (C) 2022 WYATT GROUP
+// Please see the AUTHORS file for details.
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+part of 'photo_details_cubit.dart';
+
+abstract class PhotoDetailsState extends Equatable {
+  const PhotoDetailsState();
+
+  @override
+  List<Object> get props => [];
+}
+
+class PhotoDetailsInitial extends PhotoDetailsState {}
+
+class PhotoDetailsSuccess extends PhotoDetailsState {
+  final Photo photo;
+  final bool isFavorite;
+
+  const PhotoDetailsSuccess(this.photo, {required this.isFavorite});
+
+  @override
+  List<Object> get props => [photo, isFavorite];
+}
+
+class PhotoDetailsFailure extends PhotoDetailsState {
+  final String error;
+
+  const PhotoDetailsFailure(this.error);
+
+  @override
+  List<Object> get props => [error];
+}
@@ -0,0 +1,27 @@
+// Copyright (C) 2022 WYATT GROUP
+// Please see the AUTHORS file for details.
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+import 'package:architecture_example/presentation/features/photo_details/state_management/photo_details_screen.dart';
+import 'package:flutter/material.dart';
+
+class PhotoDetails extends StatelessWidget {
+  const PhotoDetails({required this.photoId, super.key});
+
+  final int photoId;
+
+  @override
+  Widget build(BuildContext context) => PhotoDetailsScreen(photoId: photoId);
+}
@@ -0,0 +1,119 @@
+// Copyright (C) 2022 WYATT GROUP
+// Please see the AUTHORS file for details.
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+import 'package:architecture_example/domain/repositories/photo_repository.dart';
+import 'package:architecture_example/domain/usecases/photos/add_photo_to_favorites.dart';
+import 'package:architecture_example/domain/usecases/photos/check_if_photo_is_in_favorites.dart';
+import 'package:architecture_example/domain/usecases/photos/display_photo.dart';
+import 'package:architecture_example/domain/usecases/photos/remove_photo_from_favorites.dart';
+import 'package:architecture_example/presentation/features/photo_details/blocs/photo_details/photo_details_cubit.dart';
+import 'package:architecture_example/presentation/features/photo_details/state_management/photo_details_wrapper_widget.dart';
+import 'package:flutter/material.dart';
+import 'package:wyatt_bloc_helper/wyatt_bloc_helper.dart';
+
+class PhotoDetailsScreen
+    extends CubitScreen<PhotoDetailsCubit, PhotoDetailsState> {
+  const PhotoDetailsScreen({required this.photoId, super.key});
+
+  final int photoId;
+
+  @override
+  PhotoDetailsCubit create(BuildContext context) => PhotoDetailsCubit(
+        DisplayPhoto(repo<PhotoRepository>(context)),
+        CheckIfPhotoIsInFavorites(repo<PhotoRepository>(context)),
+        AddPhotoToFavorites(repo<PhotoRepository>(context)),
+        RemovePhotoFromFavorites(repo<PhotoRepository>(context)),
+      );
+
+  @override
+  PhotoDetailsCubit init(BuildContext context, PhotoDetailsCubit bloc) =>
+      bloc..load(photoId);
+
+  @override
+  Widget onWrap(BuildContext context, Widget child) =>
+      PhotoDetailsWrapperWidget(child: child);
+
+  @override
+  Widget onBuild(BuildContext context, PhotoDetailsState state) {
+    if (state is PhotoDetailsFailure) {
+      return const Center(
+        child: Text('failed to fetch photo details'),
+      );
+    }
+    if (state is PhotoDetailsSuccess) {
+      return CustomScrollView(
+        slivers: [
+          SliverAppBar(
+            expandedHeight: 400,
+            stretch: true,
+            flexibleSpace: FlexibleSpaceBar(
+              background: Stack(
+                children: [
+                  Positioned.fill(
+                    child: Image.network(
+                      state.photo.thumbnailUrl,
+                      fit: BoxFit.cover,
+                    ),
+                  ),
+                  Positioned.fill(
+                    child: Image.network(
+                      state.photo.url,
+                      fit: BoxFit.cover,
+                    ),
+                  ),
+                ],
+              ),
+            ),
+          ),
+          SliverList(
+            delegate: SliverChildListDelegate([
+              Padding(
+                padding: const EdgeInsets.symmetric(horizontal: 20),
+                child: Row(
+                  mainAxisAlignment: MainAxisAlignment.spaceBetween,
+                  children: [
+                    Flexible(
+                      child: Text(
+                        state.photo.title,
+                        overflow: TextOverflow.ellipsis,
+                        style: const TextStyle(fontWeight: FontWeight.bold),
+                      ),
+                    ),
+                    IconButton(
+                      onPressed: () {
+                        state.isFavorite
+                            ? bloc(context).removeFromFavorites()
+                            : bloc(context).addToFavorites();
+                      },
+                      icon: Icon(
+                        state.isFavorite
+                            ? Icons.favorite
+                            : Icons.favorite_outline,
+                      ),
+                    ),
+                  ],
+                ),
+              ),
+            ]),
+          ),
+        ],
+      );
+    }
+    return const Center(
+      child: CircularProgressIndicator(),
+    );
+  }
+}
@@ -0,0 +1,28 @@
+// Copyright (C) 2022 WYATT GROUP
+// Please see the AUTHORS file for details.
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+import 'package:flutter/material.dart';
+
+class PhotoDetailsWrapperWidget extends StatelessWidget {
+  const PhotoDetailsWrapperWidget({required this.child, super.key});
+
+  final Widget child;
+
+  @override
+  Widget build(BuildContext context) => Scaffold(
+        body: child,
+      );
+}
@@ -0,0 +1,40 @@
+// Copyright (C) 2022 WYATT GROUP
+// Please see the AUTHORS file for details.
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+import 'dart:async';
+
+import 'package:architecture_example/domain/usecases/photos/check_if_photo_is_in_favorites.dart';
+import 'package:equatable/equatable.dart';
+import 'package:flutter_bloc/flutter_bloc.dart';
+
+part 'favorite_checker_state.dart';
+
+class FavoriteCheckerCubit extends Cubit<FavoriteCheckerState> {
+  final CheckIfPhotoIsInFavorites _checkIfPhotoIsInFavorites;
+
+  FavoriteCheckerCubit(this._checkIfPhotoIsInFavorites)
+      : super(FavoriteCheckerInitial());
+
+  FutureOr<void> checkIfPhotoIsInFavorites(int photoId) async {
+    final response = await _checkIfPhotoIsInFavorites.call(photoId);
+    emit(
+      response.fold(
+        (value) => FavoriteCheckerSuccess(photoId, isFavorite: value),
+        (error) => FavoriteCheckerFailure(error.toString()),
+      ),
+    );
+  }
+}
@@ -0,0 +1,29 @@
+part of 'favorite_checker_cubit.dart';
+
+abstract class FavoriteCheckerState extends Equatable {
+  const FavoriteCheckerState();
+
+  @override
+  List<Object> get props => [];
+}
+
+class FavoriteCheckerInitial extends FavoriteCheckerState {}
+
+class FavoriteCheckerSuccess extends FavoriteCheckerState {
+  final int photoId;
+  final bool isFavorite;
+
+  const FavoriteCheckerSuccess(this.photoId, {required this.isFavorite});
+
+  @override
+  List<Object> get props => [photoId, isFavorite];
+}
+
+class FavoriteCheckerFailure extends FavoriteCheckerState {
+  final String error;
+
+  const FavoriteCheckerFailure(this.error);
+
+  @override
+  List<Object> get props => [error];
+}
@@ -0,0 +1,104 @@
+// Copyright (C) 2022 WYATT GROUP
+// Please see the AUTHORS file for details.
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+import 'package:architecture_example/core/enums/fetch_status.dart';
+import 'package:architecture_example/domain/entities/photo.dart';
+import 'package:architecture_example/domain/usecases/photos/open_album.dart';
+import 'package:architecture_example/domain/usecases/photos/params/query_parameters.dart';
+import 'package:bloc_concurrency/bloc_concurrency.dart';
+import 'package:equatable/equatable.dart';
+import 'package:flutter_bloc/flutter_bloc.dart';
+import 'package:stream_transform/stream_transform.dart';
+
+part 'photo_event.dart';
+part 'photo_state.dart';
+
+const _photoLimit = 40;
+const throttleDuration = Duration(milliseconds: 100);
+
+EventTransformer<E> throttleDroppable<E>(Duration duration) =>
+    (events, mapper) => droppable<E>().call(events.throttle(duration), mapper);
+
+class PhotoBloc extends Bloc<PhotoEvent, PhotoState> {
+  final OpenAlbum _openAlbum;
+
+  PhotoBloc(this._openAlbum) : super(const PhotoState()) {
+    on<PhotoFetched>(
+      _onPhotoFetched,
+      transformer: throttleDroppable(throttleDuration),
+    );
+  }
+
+  Future<void> _onPhotoFetched(
+    PhotoFetched event,
+    Emitter<PhotoState> emit,
+  ) async {
+    if (state.hasReachedMax) {
+      return;
+    }
+    if (state.status == FetchStatus.initial) {
+      final photos = await _openAlbum.call(
+        QueryParameters(
+          0,
+          _photoLimit,
+          albumId: event.albumId,
+        ),
+      );
+      return emit(
+        photos.fold(
+          (value) => state.copyWith(
+            status: FetchStatus.success,
+            photos: value,
+            hasReachedMax: false,
+          ),
+          (error) => state.copyWith(
+            status: FetchStatus.failure,
+            photos: [],
+            hasReachedMax: false,
+          ),
+        ),
+      );
+    }
+    final photos = await _openAlbum.call(
+      QueryParameters(
+        state.photos.length,
+        _photoLimit,
+        albumId: event.albumId,
+      ),
+    );
+    return emit(
+      photos.fold(
+        (value) {
+          if (value.isEmpty) {
+            return state.copyWith(
+              hasReachedMax: true,
+            );
+          }
+          return state.copyWith(
+            status: FetchStatus.success,
+            photos: List.of(state.photos)..addAll(value),
+            hasReachedMax: false,
+          );
+        },
+        (error) => state.copyWith(
+          status: FetchStatus.failure,
+          photos: List.of(state.photos),
+          hasReachedMax: false,
+        ),
+      ),
+    );
+  }
+}
@@ -0,0 +1,30 @@
+// Copyright (C) 2022 WYATT GROUP
+// Please see the AUTHORS file for details.
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+part of 'photo_bloc.dart';
+
+abstract class PhotoEvent extends Equatable {
+  const PhotoEvent();
+
+  @override
+  List<Object> get props => [];
+}
+
+class PhotoFetched extends PhotoEvent {
+  final int albumId;
+
+  const PhotoFetched(this.albumId);
+}
@@ -0,0 +1,43 @@
+// Copyright (C) 2022 WYATT GROUP
+// Please see the AUTHORS file for details.
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+part of 'photo_bloc.dart';
+
+class PhotoState extends Equatable {
+  const PhotoState({
+    this.status = FetchStatus.initial,
+    this.photos = const <Photo>[],
+    this.hasReachedMax = false,
+  });
+
+  final FetchStatus status;
+  final List<Photo> photos;
+  final bool hasReachedMax;
+
+  PhotoState copyWith({
+    FetchStatus? status,
+    List<Photo>? photos,
+    bool? hasReachedMax,
+  }) =>
+      PhotoState(
+        status: status ?? this.status,
+        photos: photos ?? this.photos,
+        hasReachedMax: hasReachedMax ?? this.hasReachedMax,
+      );
+
+  @override
+  List<Object> get props => [status, photos, hasReachedMax];
+}
@@ -0,0 +1,27 @@
+// Copyright (C) 2022 WYATT GROUP
+// Please see the AUTHORS file for details.
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+import 'package:architecture_example/presentation/features/photos/state_management/photos_screen.dart';
+import 'package:flutter/material.dart';
+
+class Photos extends StatelessWidget {
+  const Photos({required this.albumId, super.key});
+
+  final int albumId;
+
+  @override
+  Widget build(BuildContext context) => PhotosScreen(albumId: albumId);
+}
@@ -0,0 +1,61 @@
+// Copyright (C) 2022 WYATT GROUP
+// Please see the AUTHORS file for details.
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+import 'package:architecture_example/core/enums/fetch_status.dart';
+import 'package:architecture_example/domain/repositories/photo_repository.dart';
+import 'package:architecture_example/domain/usecases/photos/open_album.dart';
+import 'package:architecture_example/presentation/features/photos/blocs/photo/photo_bloc.dart';
+import 'package:architecture_example/presentation/features/photos/state_management/photos_wrapper_widget.dart';
+import 'package:architecture_example/presentation/features/photos/state_management/widgets/photos_grid.dart';
+import 'package:flutter/material.dart';
+import 'package:wyatt_bloc_helper/wyatt_bloc_helper.dart';
+
+class PhotosScreen extends BlocScreen<PhotoBloc, PhotoEvent, PhotoState> {
+  const PhotosScreen({required this.albumId, super.key});
+
+  final int albumId;
+
+  @override
+  PhotoBloc create(BuildContext context) =>
+      PhotoBloc(OpenAlbum(repo<PhotoRepository>(context)));
+
+  @override
+  PhotoBloc init(BuildContext context, PhotoBloc bloc) =>
+      bloc..add(PhotoFetched(albumId));
+
+  @override
+  Widget onWrap(BuildContext context, Widget child) => PhotosWrapperWidget(
+        child: child,
+      );
+
+  @override
+  Widget onBuild(BuildContext context, PhotoState state) {
+    switch (state.status) {
+      case FetchStatus.initial:
+        return const Center(child: CircularProgressIndicator());
+      case FetchStatus.failure:
+        return const Center(
+          child: Text('failed to fetch photos'),
+        );
+      case FetchStatus.success:
+        return PhotosGrid(
+          photos: state.photos,
+          albumId: albumId,
+          hasReachedMax: state.hasReachedMax,
+        );
+    }
+  }
+}
@@ -0,0 +1,31 @@
+// Copyright (C) 2022 WYATT GROUP
+// Please see the AUTHORS file for details.
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+import 'package:flutter/material.dart';
+
+class PhotosWrapperWidget extends StatelessWidget {
+  const PhotosWrapperWidget({required this.child, super.key});
+
+  final Widget child;
+
+  @override
+  Widget build(BuildContext context) => Scaffold(
+        appBar: AppBar(
+          title: const Text('Photos'),
+        ),
+        body: child,
+      );
+}
@@ -0,0 +1,87 @@
+// Copyright (C) 2022 WYATT GROUP
+// Please see the AUTHORS file for details.
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+import 'package:architecture_example/domain/entities/photo.dart';
+import 'package:architecture_example/presentation/features/photos/blocs/photo/photo_bloc.dart';
+import 'package:architecture_example/presentation/features/photos/state_management/widgets/photos_grid_thumbnail.dart';
+import 'package:architecture_example/presentation/shared/widgets/bottom_loader.dart';
+import 'package:flutter/material.dart';
+import 'package:flutter_bloc/flutter_bloc.dart';
+
+class PhotosGrid extends StatefulWidget {
+  const PhotosGrid({
+    required this.photos,
+    required this.albumId,
+    required this.hasReachedMax,
+    super.key,
+  });
+
+  final List<Photo> photos;
+  final int albumId;
+  final bool hasReachedMax;
+
+  @override
+  State<PhotosGrid> createState() => _PhotosGridState();
+}
+
+class _PhotosGridState extends State<PhotosGrid> {
+  final _scrollController = ScrollController();
+
+  @override
+  void initState() {
+    super.initState();
+    _scrollController.addListener(_onScroll);
+  }
+
+  @override
+  void dispose() {
+    _scrollController
+      ..removeListener(_onScroll)
+      ..dispose();
+    super.dispose();
+  }
+
+  void _onScroll() {
+    if (_isBottom) {
+      context.read<PhotoBloc>().add(PhotoFetched(widget.albumId));
+    }
+  }
+
+  bool get _isBottom {
+    if (!_scrollController.hasClients) {
+      return false;
+    }
+    final maxScroll = _scrollController.position.maxScrollExtent;
+    final currentScroll = _scrollController.offset;
+    return currentScroll >= (maxScroll * 0.9);
+  }
+
+  @override
+  Widget build(BuildContext context) => GridView.builder(
+      gridDelegate: const SliverGridDelegateWithFixedCrossAxisCount(
+        crossAxisSpacing: 4,
+        mainAxisSpacing: 4,
+        crossAxisCount: 4,
+      ),
+      itemCount: widget.hasReachedMax
+          ? widget.photos.length
+          : widget.photos.length + 1,
+      controller: _scrollController,
+      itemBuilder: (context, index) => index >= widget.photos.length
+          ? const BottomLoader()
+          : PhotosGridThumbnail(photo: widget.photos[index]),
+    );
+}
@@ -0,0 +1,63 @@
+// Copyright (C) 2022 WYATT GROUP
+// Please see the AUTHORS file for details.
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+import 'package:architecture_example/domain/entities/photo.dart';
+import 'package:architecture_example/domain/repositories/photo_repository.dart';
+import 'package:architecture_example/domain/usecases/photos/check_if_photo_is_in_favorites.dart';
+import 'package:architecture_example/presentation/features/photo_details/photo_details.dart';
+import 'package:architecture_example/presentation/features/photos/blocs/favorite_checker/favorite_checker_cubit.dart';
+import 'package:flutter/material.dart';
+import 'package:wyatt_bloc_helper/wyatt_bloc_helper.dart';
+
+class PhotosGridThumbnail
+    extends CubitScreen<FavoriteCheckerCubit, FavoriteCheckerState> {
+  const PhotosGridThumbnail({required this.photo, super.key});
+
+  final Photo photo;
+
+  @override
+  FavoriteCheckerCubit create(BuildContext context) => FavoriteCheckerCubit(
+        CheckIfPhotoIsInFavorites(repo<PhotoRepository>(context)),
+      );
+
+  @override
+  FavoriteCheckerCubit init(BuildContext context, FavoriteCheckerCubit bloc) =>
+      bloc..checkIfPhotoIsInFavorites(photo.id);
+
+  @override
+  Widget onBuild(BuildContext context, FavoriteCheckerState state) =>
+      GestureDetector(
+        onTap: () => Navigator.of(context).push(
+          MaterialPageRoute<void>(
+            builder: (context) => PhotoDetails(photoId: photo.id),
+          ),
+        ),
+        child: Stack(
+          children: [
+            Positioned.fill(
+              child: Image.network(
+                photo.thumbnailUrl,
+                fit: BoxFit.cover,
+              ),
+            ),
+            if (state is FavoriteCheckerSuccess && state.isFavorite) ...[
+              const Positioned(
+                  bottom: 10, right: 10, child: Icon(Icons.favorite),)
+            ]
+          ],
+        ),
+      );
+}