FEATURE: add news page #28

FEATURE: add news page

lib/data/datasources/news_remote.dart

@@ -0,0 +1,56 @@
+import 'package:dio/dio.dart';
+import 'package:rtu_mirea_app/common/errors/exceptions.dart';
+import 'package:rtu_mirea_app/data/models/news_item_model.dart';
+import 'dart:convert';
+
+abstract class NewsRemoteData {
+  Future<List<NewsItemModel>> getNews(int offset, int limit, [String? tag]);
+  Future<List<String>> getTags();
+}
+
+class NewsRemoteDataImpl extends NewsRemoteData {
+  static const _API_BASE_URL = "http://schedule.mirea.ninja:5050";
+
+  final Dio httpClient;
+
+  NewsRemoteDataImpl({required this.httpClient});
+
+  @override
+  Future<List<NewsItemModel>> getNews(int offset, int limit,
+      [String? tag]) async {
+    try {
+      final response = await httpClient.get(
+          _API_BASE_URL + '/news' + '?tag=$tag&limit=$limit&offset=$offset');
+
+      if (response.statusCode == 200) {
+        Map responseBody = response.data;
+        return responseBody["news"]
+            .map<NewsItemModel>((newsItem) => NewsItemModel.fromJson(newsItem))
+            .toList();
+      } else {
+        throw ServerException('Response status code is $response.statusCode');
+      }
+    } catch (e) {
+      throw ServerException(e.toString());
+    }
+  }
+
+  @override
+  Future<List<String>> getTags() async {
+    try {
+      final response = await httpClient.get(_API_BASE_URL + '/tags');
+
+      if (response.statusCode == 200) {
+        Map responseBody = response.data;
+
+        List<String> tags = [];
+        tags = List<String>.from(responseBody["tags"].map((x) => x['name']));
+        return tags;
+      } else {
+        throw ServerException('Response status code is $response.statusCode');
+      }
+    } catch (e) {
+      throw ServerException(e.toString());
+    }
+  }
+}

lib/data/models/news_item_model.dart

@@ -0,0 +1,30 @@
+import 'package:rtu_mirea_app/domain/entities/news_item.dart';
+
+class NewsItemModel extends NewsItem {
+  NewsItemModel({
+    required title,
+    required text,
+    required date,
+    required images,
+    required tags,
+  }) : super(
+          title: title,
+          text: text,
+          date: date,
+          images: images,
+          tags: tags,
+        );
+
+  factory NewsItemModel.fromJson(Map<String, dynamic> json) {
+    return NewsItemModel(
+      title: json['title'],
+      text: json['text'],
+      date: DateTime.parse(json['date']),
+      images: List<String>.from(json["images"].map((x) => x['name'])),
+      tags: List<String>.from(json["tags"].map((x) => x['name'])),
+    );
+  }
+
+  @override
+  List<Object?> get props => [title, text, date, images, tags];
+}

lib/data/repositories/news_repository_impl.dart

@@ -0,0 +1,46 @@
+import 'package:dartz/dartz.dart';
+import 'package:internet_connection_checker/internet_connection_checker.dart';
+import 'package:rtu_mirea_app/common/errors/exceptions.dart';
+import 'package:rtu_mirea_app/common/errors/failures.dart';
+import 'package:rtu_mirea_app/data/datasources/news_remote.dart';
+import 'package:rtu_mirea_app/domain/entities/news_item.dart';
+import 'package:rtu_mirea_app/domain/repositories/news_repository.dart';
+
+class NewsRepositoryImpl implements NewsRepository {
+  final NewsRemoteData remoteDataSource;
+  final InternetConnectionChecker connectionChecker;
+
+  NewsRepositoryImpl({
+    required this.remoteDataSource,
+    required this.connectionChecker,
+  });
+
+  @override
+  Future<Either<Failure, List<NewsItem>>> getNews(int offset, int limit,
+      [String? tag]) async {
+    if (await connectionChecker.hasConnection) {
+      try {
+        final newsList = await remoteDataSource.getNews(offset, limit, tag);
+        return Right(newsList);
+      } on ServerException {
+        return Left(ServerFailure());
+      }
+    } else {
+      return Left(ServerFailure());
+    }
+  }
+
+  @override
+  Future<Either<Failure, List<String>>> getTags() async {
+    if (await connectionChecker.hasConnection) {
+      try {
+        final tagsList = await remoteDataSource.getTags();
+        return Right(tagsList);
+      } on ServerException {
+        return Left(ServerFailure());
+      }
+    } else {
+      return Left(ServerFailure());
+    }
+  }
+}

lib/domain/entities/news_item.dart

@@ -0,0 +1,20 @@
+import 'package:equatable/equatable.dart';
+
+class NewsItem extends Equatable {
+  final String title;
+  final String text;
+  final DateTime date;
+  final List<String> images;
+  final List<String> tags;
+
+  NewsItem({
+    required this.title,
+    required this.text,
+    required this.date,
+    required this.images,
+    required this.tags,
+  });
+
+  @override
+  List<Object?> get props => [title, text, date, images, tags];
+}

lib/domain/repositories/news_repository.dart

@@ -0,0 +1,9 @@
+import 'package:dartz/dartz.dart';
+import 'package:rtu_mirea_app/common/errors/failures.dart';
+import 'package:rtu_mirea_app/domain/entities/news_item.dart';
+
+abstract class NewsRepository {
+  Future<Either<Failure, List<NewsItem>>> getNews(
+      int offset, int limit, String tag);
+  Future<Either<Failure, List<String>>> getTags();
+}

lib/domain/usecases/get_news.dart

@@ -0,0 +1,29 @@
+import 'package:dartz/dartz.dart';
+import 'package:equatable/equatable.dart';
+import 'package:rtu_mirea_app/common/errors/failures.dart';
+import 'package:rtu_mirea_app/domain/entities/news_item.dart';
+import 'package:rtu_mirea_app/domain/repositories/news_repository.dart';
+import 'package:rtu_mirea_app/domain/usecases/usecase.dart';
+
+class GetNews extends UseCase<List<NewsItem>, GetNewsParams> {
+  final NewsRepository newsRepository;
+
+  GetNews(this.newsRepository);
+
+  @override
+  Future<Either<Failure, List<NewsItem>>> call(GetNewsParams params) async {
+    return await newsRepository.getNews(
+        params.offset, params.limit, params.tag ?? 'все');
+  }
+}
+
+class GetNewsParams extends Equatable {
+  final int offset;
+  final int limit;
+  final String? tag;
+
+  GetNewsParams({required this.offset, required this.limit, this.tag});
+
+  @override
+  List<Object?> get props => [offset, limit, tag];
+}

lib/domain/usecases/get_news_tags.dart

@@ -0,0 +1,15 @@
+import 'package:dartz/dartz.dart';
+import 'package:rtu_mirea_app/common/errors/failures.dart';
+import 'package:rtu_mirea_app/domain/repositories/news_repository.dart';
+import 'package:rtu_mirea_app/domain/usecases/usecase.dart';
+
+class GetNewsTags extends UseCase<List<String>, void> {
+  final NewsRepository newsRepository;
+
+  GetNewsTags(this.newsRepository);
+
+  @override
+  Future<Either<Failure, List<String>>> call([_]) async {
+    return await newsRepository.getTags();
+  }
+}

lib/main.dart

@@ -4,10 +4,12 @@ import 'package:flutter/services.dart';
 import 'package:flutter_bloc/flutter_bloc.dart';
 import 'package:rtu_mirea_app/presentation/bloc/home_navigator_bloc/home_navigator_bloc.dart';
 import 'package:rtu_mirea_app/presentation/bloc/map_cubit/map_cubit.dart';
+import 'package:rtu_mirea_app/presentation/bloc/news_bloc/news_bloc.dart';
 import 'package:rtu_mirea_app/presentation/bloc/onboarding_cubit/onboarding_cubit.dart';
 import 'package:rtu_mirea_app/presentation/bloc/schedule_bloc/schedule_bloc.dart';
 import 'package:rtu_mirea_app/presentation/pages/home/home_navigator_screen.dart';
 import 'package:rtu_mirea_app/presentation/pages/map/map_screen.dart';
+import 'package:rtu_mirea_app/presentation/pages/news/news_screen.dart';
 import 'package:rtu_mirea_app/presentation/pages/onboarding/onboarding_screen.dart';
 import 'package:rtu_mirea_app/presentation/pages/schedule/schedule_screen.dart';
 import 'package:rtu_mirea_app/presentation/pages/profile/profile_screen.dart';
@@ -61,6 +63,7 @@ class App extends StatelessWidget {
         BlocProvider<OnboardingCubit>(
             create: (context) => getIt<OnboardingCubit>()),
         BlocProvider<MapCubit>(create: (context) => getIt<MapCubit>()),
+        BlocProvider<NewsBloc>(create: (context) => getIt<NewsBloc>()),
       ],
       child: AdaptiveTheme(
         light: lightTheme,
@@ -75,7 +78,8 @@ class App extends StatelessWidget {
             ScheduleScreen.routeName: (context) => ScheduleScreen(),
             MapScreen.routeName: (context) => MapScreen(),
             ProfileScreen.routeName: (context) => ProfileScreen(),
-            OnBoardingScreen.routeName: (context) => OnBoardingScreen()
+            OnBoardingScreen.routeName: (context) => OnBoardingScreen(),
+            NewsScreen.routeName: (context) => NewsScreen()
           },
         ),
       ),

lib/presentation/bloc/home_navigator_bloc/home_navigator_bloc.dart

@@ -4,6 +4,7 @@ import 'package:bloc/bloc.dart';
 import 'package:equatable/equatable.dart';
 import 'package:flutter/material.dart';
 import 'package:rtu_mirea_app/presentation/pages/map/map_screen.dart';
+import 'package:rtu_mirea_app/presentation/pages/news/news_screen.dart';
 import 'package:rtu_mirea_app/presentation/pages/profile/profile_screen.dart';
 import 'package:rtu_mirea_app/presentation/pages/schedule/schedule_screen.dart';
 
@@ -32,6 +33,9 @@ class HomeNavigatorBloc extends Bloc<HomeNavigatorEvent, HomeNavigatorState> {
           case MapScreen.routeName:
             yield MapPage();
             break;
+          case NewsScreen.routeName:
+            yield NewsPage();
+            break;
           default:
             break;
         }

lib/presentation/bloc/home_navigator_bloc/home_navigator_state.dart

@@ -19,7 +19,6 @@ class SchedulePage extends HomeNavigatorState {
   List<Object> get props => [_screen];
 }
 
-
 class MapPage extends HomeNavigatorState {
   final _screen = MapScreen();
 
@@ -39,3 +38,13 @@ class ProfilePage extends HomeNavigatorState {
   @override
   List<Object> get props => [_screen];
 }
+
+class NewsPage extends HomeNavigatorState {
+  final _screen = NewsScreen();
+
+  @override
+  Widget get screen => _screen;
+
+  @override
+  List<Object> get props => [_screen];
+}

lib/presentation/bloc/news_bloc/news_bloc.dart

@@ -0,0 +1,64 @@
+import 'dart:async';
+
+import 'package:bloc/bloc.dart';
+import 'package:equatable/equatable.dart';
+import 'package:rtu_mirea_app/domain/entities/news_item.dart';
+import 'package:rtu_mirea_app/domain/usecases/get_news.dart';
+import 'package:rtu_mirea_app/domain/usecases/get_news_tags.dart';
+
+part 'news_event.dart';
+part 'news_state.dart';
+
+class NewsBloc extends Bloc<NewsEvent, NewsState> {
+  NewsBloc({
+    required this.getNews,
+    required this.getNewsTags,
+  }) : super(NewsInitial());
+
+  final GetNews getNews;
+  final GetNewsTags getNewsTags;
+
+  bool _isFirstFetch = true;
+  int _offset = 0;
+
+  @override
+  Stream<NewsState> mapEventToState(
+    NewsEvent event,
+  ) async* {
+    if (event is NewsLoadEvent) {
+      List<String> tagsList = [];
+      List<NewsItem> oldNews = [];
+
+      bool hasFetchError = false;
+
+      if (_isFirstFetch) {
+        yield NewsLoading(oldNews: oldNews, isFirstFetch: true);
+        _isFirstFetch = false;
+        final tags = await getNewsTags();
+        tags.fold((failure) {
+          hasFetchError = true;
+        }, (r) {
+          tagsList = r;
+        });
+      } else {
+        if (state is NewsLoaded) {
+          tagsList = (state as NewsLoaded).tags;
+          oldNews = (state as NewsLoaded).news;
+        }
+        yield NewsLoading(oldNews: oldNews, isFirstFetch: false);
+      }
+
+      if (hasFetchError) {
+        yield NewsLoadError();
+        return;
+      }
+
+      final news = await getNews(GetNewsParams(offset: _offset, limit: 10));
+      yield news.fold((failure) => NewsLoadError(), (r) {
+        _offset += r.length - 1;
+        List<NewsItem> newNews = List.from(oldNews)..addAll(r);
+        return NewsLoaded(news: newNews, tags: tagsList);
+      });
+    }
+  }
+}

lib/presentation/bloc/news_bloc/news_event.dart

@@ -0,0 +1,12 @@
+part of 'news_bloc.dart';
+
+abstract class NewsEvent extends Equatable {
+  const NewsEvent();
+
+  @override
+  List<Object> get props => [];
+}
+
+class NewsLoadTagsEvent extends NewsEvent {}
+
+class NewsLoadEvent extends NewsEvent {}