fix: The HeadlinesFeedBloc has been updated to correctly format multiple selected category IDs and source IDs as comma-separated strings when making API requests. This aligns with the backend's expectation and should resolve the bug where new filter selections were overriding previous ones instead of being combined. Filtering by multiple categories and/or multiple sources simultaneously should now work as intended.

Author: fulleni

lib/headlines-feed/bloc/headlines_feed_bloc.dart

@@ -60,20 +60,22 @@ class HeadlinesFeedBloc extends Bloc<HeadlinesFeedEvent, HeadlinesFeedState> {
   ) async {
     emit(HeadlinesFeedLoading()); // Show loading for filter application
     try {
-      final response = await _headlinesRepository.readAllByQuery({
-        if (event.filter.categories?.isNotEmpty ?? false)
-          'categories':
-              event.filter.categories!
-                  .whereType<Category>()
-                  .map((c) => c.id)
-                  .toList(),
-        if (event.filter.sources?.isNotEmpty ?? false)
-          'sources':
-              event.filter.sources!
-                  .whereType<Source>()
-                  .map((s) => s.id)
-                  .toList(),
-      }, limit: _headlinesFetchLimit,);
+      final queryParams = <String, dynamic>{};
+      if (event.filter.categories?.isNotEmpty ?? false) {
+        queryParams['categories'] = event.filter.categories!
+            .map((c) => c.id)
+            .join(',');
+      }
+      if (event.filter.sources?.isNotEmpty ?? false) {
+        queryParams['sources'] = event.filter.sources!
+            .map((s) => s.id)
+            .join(',');
+      }
+
+      final response = await _headlinesRepository.readAllByQuery(
+        queryParams,
+        limit: _headlinesFetchLimit,
+      );
       emit(
         HeadlinesFeedLoaded(
           headlines: response.items,
@@ -133,8 +135,8 @@ class HeadlinesFeedBloc extends Bloc<HeadlinesFeedEvent, HeadlinesFeedState> {
     Emitter<HeadlinesFeedState> emit,
   ) async {
     // Determine current filter and cursor based on state
-    var currentFilter = const HeadlineFilter();
-    var currentCursor =
+    HeadlineFilter currentFilter = const HeadlineFilter(); // Made type explicit
+    String? currentCursor = // Made type explicit
         event.cursor; // Use event's cursor if provided (for pagination)
     var currentHeadlines = <Headline>[];
     var isPaginating = false;
@@ -169,21 +171,20 @@ class HeadlinesFeedBloc extends Bloc<HeadlinesFeedEvent, HeadlinesFeedState> {
     }
 
     try {
+      final queryParams = <String, dynamic>{};
+      if (currentFilter.categories?.isNotEmpty ?? false) {
+        queryParams['categories'] = currentFilter.categories!
+            .map((c) => c.id)
+            .join(',');
+      }
+      if (currentFilter.sources?.isNotEmpty ?? false) {
+        queryParams['sources'] = currentFilter.sources!
+            .map((s) => s.id)
+            .join(',');
+      }
+
       final response = await _headlinesRepository.readAllByQuery(
-        {
-          if (currentFilter.categories?.isNotEmpty ?? false)
-            'categories':
-                currentFilter.categories!
-                    .whereType<Category>()
-                    .map((c) => c.id)
-                    .toList(),
-          if (currentFilter.sources?.isNotEmpty ?? false)
-            'sources':
-                currentFilter.sources!
-                    .whereType<Source>()
-                    .map((s) => s.id)
-                    .toList(),
-        },
+        queryParams,
         limit: _headlinesFetchLimit,
         startAfterId: currentCursor, // Use determined cursor
       );
@@ -216,27 +217,29 @@ class HeadlinesFeedBloc extends Bloc<HeadlinesFeedEvent, HeadlinesFeedState> {
     emit(HeadlinesFeedLoading()); // Show loading indicator for refresh
 
     // Determine the filter currently applied in the state
-    var currentFilter = const HeadlineFilter();
+    HeadlineFilter currentFilter = const HeadlineFilter(); // Made type explicit
     if (state is HeadlinesFeedLoaded) {
       currentFilter = (state as HeadlinesFeedLoaded).filter;
     }
 
     try {
+      final queryParams = <String, dynamic>{};
+      if (currentFilter.categories?.isNotEmpty ?? false) {
+        queryParams['categories'] = currentFilter.categories!
+            .map((c) => c.id)
+            .join(',');
+      }
+      if (currentFilter.sources?.isNotEmpty ?? false) {
+        queryParams['sources'] = currentFilter.sources!
+            .map((s) => s.id)
+            .join(',');
+      }
+
       // Fetch the first page using the current filter
-      final response = await _headlinesRepository.readAllByQuery({
-        if (currentFilter.categories?.isNotEmpty ?? false)
-          'categories':
-              currentFilter.categories!
-                  .whereType<Category>()
-                  .map((c) => c.id)
-                  .toList(),
-        if (currentFilter.sources?.isNotEmpty ?? false)
-          'sources':
-              currentFilter.sources!
-                  .whereType<Source>()
-                  .map((s) => s.id)
-                  .toList(),
-      }, limit: _headlinesFetchLimit,);
+      final response = await _headlinesRepository.readAllByQuery(
+        queryParams,
+        limit: _headlinesFetchLimit,
+      );
       emit(
         HeadlinesFeedLoaded(
           headlines: response.items, // Replace headlines on refresh