improve loading speed. (#414)

lib/blocs/stories/stories_bloc.dart

@@ -13,6 +13,7 @@ import 'package:responsive_builder/responsive_builder.dart';
 import 'package:rxdart/rxdart.dart';
 
 part 'stories_event.dart';
+
 part 'stories_state.dart';
 
 class StoriesBloc extends Bloc<StoriesEvent, StoriesState> {
@@ -95,7 +96,8 @@ class StoriesBloc extends Bloc<StoriesEvent, StoriesState> {
         storiesToBeDownloaded: state.storiesToBeDownloaded,
       ),
     );
-    for (final StoryType type in StoryType.values) {
+
+    for (final StoryType type in _preferenceCubit.state.tabs) {
       add(LoadStories(type: type));
     }
   }
@@ -111,28 +113,44 @@ class StoriesBloc extends Bloc<StoriesEvent, StoriesState> {
       emit(
         state
             .copyWithStoryIdsUpdated(type: type, to: ids)
-            .copyWithCurrentPageUpdated(type: type, to: 0),
+            .copyWithCurrentPageUpdated(type: type, to: 0)
+            .copyWithStatusUpdated(type: type, to: Status.inProgress),
       );
       _offlineRepository
           .getCachedStoriesStream(
             ids: ids.sublist(0, min(ids.length, state.currentPageSize)),
           )
-          .listen((Story story) {
+          .listen((Story story) => add(StoryLoaded(story: story, type: type)))
-        add(StoryLoaded(story: story, type: type));
+          .onDone(() => add(StoriesLoaded(type: type)));
-      }).onDone(() {
-        add(StoriesLoaded(type: type));
-      });
     } else {
       final List<int> ids =
           await _hackerNewsRepository.fetchStoryIds(type: type);
       emit(
         state
             .copyWithStoryIdsUpdated(type: type, to: ids)
-            .copyWithCurrentPageUpdated(type: type, to: 0),
+            .copyWithCurrentPageUpdated(type: type, to: 0)
+            .copyWithStatusUpdated(type: type, to: Status.inProgress),
       );
+      bool hasFirstArrived = false;
       await _hackerNewsRepository
-          .fetchStoriesStream(ids: ids.sublist(0, state.currentPageSize))
+          .fetchStoriesStream(
+        ids: ids.sublist(0, state.currentPageSize),
+        sequential: !event.isRefreshing,
+      )
           .listen((Story story) {
+        /// When it's refreshing, only flush
+        /// previous stories when new stories has been fetched.
+        if (event.isRefreshing && !hasFirstArrived) {
+          hasFirstArrived = true;
+          final Map<StoryType, List<Story>> newStoriesMap =
+              Map<StoryType, List<Story>>.from(state.storiesByType);
+          newStoriesMap[type] = <Story>[];
+          emit(
+            state.copyWith(
+              storiesByType: newStoriesMap,
+            ),
+          );
+        }
         add(StoryLoaded(story: story, type: type));
       }).asFuture<void>();
       add(StoriesLoaded(type: type));
@@ -161,11 +179,13 @@ class StoriesBloc extends Bloc<StoriesEvent, StoriesState> {
       );
     } else {
       emit(state.copyWithRefreshed(type: event.type));
-      add(LoadStories(type: event.type));
+      add(LoadStories(type: event.type, isRefreshing: true));
     }
   }
 
   void onLoadMore(StoriesLoadMore event, Emitter<StoriesState> emit) {
+    if (state.statusByType[event.type] == Status.inProgress) return;
+
     emit(
       state.copyWithStatusUpdated(
         type: event.type,
@@ -195,16 +215,10 @@ class StoriesBloc extends Bloc<StoriesEvent, StoriesState> {
                 upper,
               ),
             )
-            .listen((Story story) {
+            .listen(
-          add(
+              (Story story) => add(StoryLoaded(story: story, type: event.type)),
-            StoryLoaded(
+            )
-              story: story,
+            .onDone(() => add(StoriesLoaded(type: event.type)));
-              type: event.type,
-            ),
-          );
-        }).onDone(() {
-          add(StoriesLoaded(type: event.type));
-        });
       } else {
         _hackerNewsRepository
             .fetchStoriesStream(
@@ -213,16 +227,10 @@ class StoriesBloc extends Bloc<StoriesEvent, StoriesState> {
                 upper,
               ),
             )
-            .listen((Story story) {
+            .listen(
-          add(
+              (Story story) => add(StoryLoaded(story: story, type: event.type)),
-            StoryLoaded(
+            )
-              story: story,
+            .onDone(() => add(StoriesLoaded(type: event.type)));
-              type: event.type,
-            ),
-          );
-        }).onDone(() {
-          add(StoriesLoaded(type: event.type));
-        });
       }
     } else {
       emit(

lib/blocs/stories/stories_event.dart

@@ -6,12 +6,16 @@ abstract class StoriesEvent extends Equatable {
 }
 
 class LoadStories extends StoriesEvent {
-  LoadStories({required this.type});
+  LoadStories({required this.type, this.isRefreshing = false});
 
   final StoryType type;
+  final bool isRefreshing;
 
   @override
-  List<Object?> get props => <Object?>[type];
+  List<Object?> get props => <Object?>[
+        type,
+        isRefreshing,
+      ];
 }
 
 class StoriesInitialize extends StoriesEvent {

lib/blocs/stories/stories_state.dart

@@ -150,12 +150,6 @@ class StoriesState extends Equatable {
   }
 
   StoriesState copyWithRefreshed({required StoryType type}) {
-    final Map<StoryType, List<Story>> newStoriesMap =
-        Map<StoryType, List<Story>>.from(storiesByType);
-    newStoriesMap[type] = <Story>[];
-    final Map<StoryType, List<int>> newStoryIdsMap =
-        Map<StoryType, List<int>>.from(storyIdsByType);
-    newStoryIdsMap[type] = <int>[];
     final Map<StoryType, Status> newStatusMap =
         Map<StoryType, Status>.from(statusByType);
     newStatusMap[type] = Status.inProgress;
@@ -163,8 +157,6 @@ class StoriesState extends Equatable {
         Map<StoryType, int>.from(currentPageByType);
     newCurrentPageMap[type] = 0;
     return copyWith(
-      storiesByType: newStoriesMap,
-      storyIdsByType: newStoryIdsMap,
       statusByType: newStatusMap,
       currentPageByType: newCurrentPageMap,
     );

lib/main.dart

@@ -281,13 +281,21 @@ class HackiApp extends StatelessWidget {
                         .instance.platformDispatcher.platformBrightness,
                     mode,
                   );
-                  final bool isDarkModeEnabled = mode == null ||
+                  final bool isDarkModeEnabled = () {
-                      mode == AdaptiveThemeMode.dark ||
+                    if (mode == null) {
+                      return View.of(context)
+                              .platformDispatcher
+                              .platformBrightness ==
+                          Brightness.dark;
+                    } else {
+                      return mode == AdaptiveThemeMode.dark ||
                           (mode == AdaptiveThemeMode.system &&
                               View.of(context)
                                       .platformDispatcher
                                       .platformBrightness ==
                                   Brightness.dark);
+                    }
+                  }();
                   final ColorScheme colorScheme = ColorScheme.fromSeed(
                     brightness:
                         isDarkModeEnabled ? Brightness.dark : Brightness.light,

lib/repositories/hacker_news_repository.dart

@@ -329,7 +329,11 @@ class HackerNewsRepository {
 
   /// Fetch a list of [Story] based on ids and return results
   /// using a stream.
-  Stream<Story> fetchStoriesStream({required List<int> ids}) async* {
+  Stream<Story> fetchStoriesStream({
+    required List<int> ids,
+    bool sequential = false,
+  }) async* {
+    if (sequential) {
       for (final int id in ids) {
         final Story? story =
             await _fetchItemJson(id).then((Map<String, dynamic>? json) async {
@@ -342,6 +346,18 @@ class HackerNewsRepository {
           yield story;
         }
       }
+    } else {
+      final List<Map<String, dynamic>?> responses = await Future.wait(
+        <Future<Map<String, dynamic>?>>[
+          ...ids.map(_fetchItemJson),
+        ],
+      );
+      for (final Map<String, dynamic>? json in responses) {
+        if (json == null) continue;
+        final Story story = Story.fromJson(json);
+        yield story;
+      }
+    }
   }
 
   /// Fetch a list of [PollOption] based on ids and return results

lib/screens/widgets/story_tile.dart

@@ -3,10 +3,12 @@ import 'package:flutter_bloc/flutter_bloc.dart';
 import 'package:flutter_fadein/flutter_fadein.dart';
 import 'package:hacki/blocs/blocs.dart';
 import 'package:hacki/config/constants.dart';
+import 'package:hacki/cubits/cubits.dart';
 import 'package:hacki/extensions/extensions.dart';
 import 'package:hacki/models/models.dart';
 import 'package:hacki/screens/widgets/widgets.dart';
 import 'package:hacki/styles/styles.dart';
+import 'package:hacki/utils/utils.dart';
 import 'package:shimmer/shimmer.dart';
 
 class StoryTile extends StatelessWidget {
@@ -123,6 +125,17 @@ class StoryTile extends StatelessWidget {
         excludeSemantics: true,
         child: InkWell(
           onTap: onTap,
+          onLongPress: () {
+            if (story.url.isNotEmpty) {
+              LinkUtil.launch(
+                story.url,
+                context,
+                useReader: context.read<PreferenceCubit>().state.readerEnabled,
+                offlineReading:
+                    context.read<StoriesBloc>().state.isOfflineReading,
+              );
+            }
+          },
           child: Padding(
             padding: const EdgeInsets.only(left: Dimens.pt12),
             child: Column(