Merge pull request #187 from flutter-news-app-full-source-code/feat/dicover

Feat/dicover

Author: fulleni

CHANGELOG.md

@@ -2,6 +2,7 @@
 
 ## Upcoming Release
 
+ - **feat**: implement discover feature for browsing news sources by category with filtering and follow/unfollow functionality.
  - **refactor!**: Overhauled the application startup and authentication lifecycle to be robust and free of race conditions. This was a major architectural change that introduced a new `AppInitializationPage` and `AppInitializationBloc` to act as a "gatekeeper," ensuring all critical data is fetched *before* the main UI is built. This fixes a class of bugs related to indefinite loading screens, data migration on account linking, and inconsistent state during startup.
 
 ## 1.4.0 - 2025-10-17

README.md

@@ -38,6 +38,7 @@ Click on any category to explore.
 - **Advanced Filter Creation:** A dedicated, full-screen interface allows users to build complex filters by combining multiple `Topics`, `Sources`, and `Countries`.
 - **Saved Filters:** Users can name and save their custom filter combinations. These filters appear in the quick-access bar and can be reordered for a fully customized experience.
 - **Integrated Headline Search:** A sleek search bar in the main feed's scrolling app bar provides a focused, full-screen search experience for headlines. A user avatar within the search bar offers instant modal access to account settings.
+- **Intuitive Source Discovery:** A dedicated "Discover" tab provides a rich, multi-layered exploration experience. Users can browse sources by category in horizontally scrolling carousels, dive deeper into full lists with infinite scrolling and country-based filtering, and find specific sources using a familiar, contextual search bar.
 > **🎯 Your Advantage:** Give your users powerful content discovery tools that keep them engaged and coming back for more.
 
 </details>
@@ -122,8 +123,9 @@ Gain complete command over your application's operational state and user experie
 ---
 
 ### 🛠️ Flexible Environment Configuration
-- Easily switch between development (in-memory data or local API) and production environments with a simple code change. This empowers rapid prototyping, robust testing, and seamless deployment.
-> **🚀 Your Advantage:** A flexible setup that speeds up your development cycle and makes deployment simple.
+- The app utilizes compile-time variables (`--dart-define`) to seamlessly switch between `production`, `development`, and `demo` environments. This production-ready approach ensures that environment-specific configurations, like API endpoints, are set at build time, eliminating the risk of shipping a production app with development settings.
+- Includes pre-configured VS Code `launch.json` profiles for all environments, enabling one-click running and debugging for any target configuration.
+> **🚀 Your Advantage:** A robust, professional environment setup that streamlines the development-to-production workflow and prevents common configuration errors.
 
 ---
 

lib/account/view/saved_filters_page.dart

@@ -70,7 +70,7 @@ class SavedFiltersPage extends StatelessWidget {
                   onSelected: (value) async {
                     switch (value) {
                       case 'rename':
-                        showDialog<void>(
+                        await showDialog<void>(
                           context: context,
                           builder: (_) => SaveFilterDialog(
                             initialValue: filter.name,

lib/discover/bloc/discover_bloc.dart

@@ -0,0 +1,76 @@
+import 'package:bloc/bloc.dart';
+import 'package:collection/collection.dart';
+import 'package:core/core.dart';
+import 'package:data_repository/data_repository.dart';
+import 'package:equatable/equatable.dart';
+import 'package:logging/logging.dart';
+
+part 'discover_event.dart';
+part 'discover_state.dart';
+
+/// {@template discover_bloc}
+/// A BLoC that manages the state of the discover feature.
+///
+/// This BLoC is responsible for fetching all available news sources and
+/// grouping them by their respective [SourceType] for display on the
+/// discover page.
+/// {@endtemplate}
+class DiscoverBloc extends Bloc<DiscoverEvent, DiscoverState> {
+  /// {@macro discover_bloc}
+  DiscoverBloc({
+    required DataRepository<Source> sourcesRepository,
+    required Logger logger,
+  }) : _sourcesRepository = sourcesRepository,
+       _logger = logger,
+       super(const DiscoverState()) {
+    on<DiscoverStarted>(_onDiscoverStarted);
+  }
+
+  final DataRepository<Source> _sourcesRepository;
+  final Logger _logger;
+
+  /// Handles the initial fetching and grouping of all sources.
+  ///
+  /// When [DiscoverStarted] is added, this method fetches all sources from
+  /// the repository, groups them into a map by [SourceType], and emits
+  /// a success or failure state.
+  Future<void> _onDiscoverStarted(
+    DiscoverStarted event,
+    Emitter<DiscoverState> emit,
+  ) async {
+    _logger.fine('[DiscoverBloc] DiscoverStarted event received.');
+    emit(state.copyWith(status: DiscoverStatus.loading));
+
+    try {
+      // Fetch all available sources from the repository.
+      final sourcesResponse = await _sourcesRepository.readAll();
+      _logger.info(
+        '[DiscoverBloc] Successfully fetched ${sourcesResponse.items.length} sources.',
+      );
+
+      // Group the fetched sources by their sourceType.
+      final groupedSources = groupBy<Source, SourceType>(
+        sourcesResponse.items,
+        (source) => source.sourceType,
+      );
+
+      emit(
+        state.copyWith(
+          status: DiscoverStatus.success,
+          groupedSources: groupedSources,
+        ),
+      );
+    } on HttpException catch (e, s) {
+      _logger.severe('[DiscoverBloc] Failed to fetch sources.', e, s);
+      emit(state.copyWith(status: DiscoverStatus.failure, error: e));
+    } catch (e, s) {
+      _logger.severe('[DiscoverBloc] Failed to fetch sources.', e, s);
+      emit(
+        state.copyWith(
+          status: DiscoverStatus.failure,
+          error: UnknownException('An unexpected error occurred: $e'),
+        ),
+      );
+    }
+  }
+}

lib/discover/bloc/discover_event.dart

@@ -0,0 +1,16 @@
+part of 'discover_bloc.dart';
+
+/// Base class for all events related to the [DiscoverBloc].
+sealed class DiscoverEvent extends Equatable {
+  /// {@macro discover_event}
+  const DiscoverEvent();
+
+  @override
+  List<Object> get props => [];
+}
+
+/// {@template discover_started}
+/// Event added when the discover feature is first started.
+/// This triggers the initial fetch of all available sources.
+/// {@endtemplate}
+final class DiscoverStarted extends DiscoverEvent {}

lib/discover/bloc/discover_state.dart

@@ -0,0 +1,55 @@
+part of 'discover_bloc.dart';
+
+/// The status of the [DiscoverBloc].
+enum DiscoverStatus {
+  /// The initial state.
+  initial,
+
+  /// The state when loading data.
+  loading,
+
+  /// The state when data has been successfully loaded.
+  success,
+
+  /// The state when an error has occurred.
+  failure,
+}
+
+/// {@template discover_state}
+/// The state of the discover feature, which holds the grouped sources.
+/// {@endtemplate}
+final class DiscoverState extends Equatable {
+  /// {@macro discover_state}
+  const DiscoverState({
+    this.status = DiscoverStatus.initial,
+    this.groupedSources = const {},
+    this.error,
+  });
+
+  /// The current status of the discover feature.
+  final DiscoverStatus status;
+
+  /// A map of sources grouped by their [SourceType].
+  final Map<SourceType, List<Source>> groupedSources;
+
+  /// The error that occurred, if any.
+  final Exception? error;
+
+  /// Creates a copy of the current [DiscoverState] with the given fields
+  /// replaced with the new values.
+  DiscoverState copyWith({
+    DiscoverStatus? status,
+    Map<SourceType, List<Source>>? groupedSources,
+    Exception? error,
+    bool clearError = false,
+  }) {
+    return DiscoverState(
+      status: status ?? this.status,
+      groupedSources: groupedSources ?? this.groupedSources,
+      error: clearError ? null : error ?? this.error,
+    );
+  }
+
+  @override
+  List<Object?> get props => [status, groupedSources, error];
+}