Update comment count when adding a comment

lib/viewmodels/comments_view_model.dart

@@ -6,6 +6,7 @@ import "package:proxima/models/database/post/post_id_firestore.dart";
 import "package:proxima/models/ui/comment_details.dart";
 import "package:proxima/services/database/comment/comment_repository_service.dart";
 import "package:proxima/services/database/user_repository_service.dart";
+import "package:proxima/viewmodels/post_comment_count_view_model.dart";
 
 /// This view model is used to fetch the comments of a post.
 /// It fetches the comments under the post with the id [arg] and returns
@@ -45,6 +46,9 @@ class CommentsViewModel extends AutoDisposeFamilyAsyncNotifier<
           -commentA.publicationDate.compareTo(commentB.publicationDate),
     );
 
+    // Update the post comment count
+    ref.read(postCommentCountProvider(arg).notifier).setCount(comments.length);
+
     return sortedComments;
   }
 

lib/viewmodels/post_comment_count_view_model.dart

@@ -0,0 +1,35 @@
+import "package:hooks_riverpod/hooks_riverpod.dart";
+import "package:proxima/models/database/post/post_id_firestore.dart";
+import "package:proxima/services/database/post_repository_service.dart";
+
+/// This view model is used to keep in memory the number of comments of a post.
+/// It is refreshed every time the post comment list is refreshed, to stay consistent
+/// with it. It is also refreshed when a comment is deleted.
+/// The fact that it is auto-dispose allows to keep the memory usage low, keeping only
+/// the count of the comments of the posts that are currently displayed on the screen.
+/// This may moreover help mitigate some reloading bugs, since it suffices to scroll
+/// the post out of the screen to dispose the view model and thus the count of the comments.
+class PostCommentCountViewModel
+    extends AutoDisposeFamilyAsyncNotifier<int, PostIdFirestore> {
+  @override
+  Future<int> build(PostIdFirestore arg) async {
+    final postRepo = ref.watch(postRepositoryServiceProvider);
+    final post = await postRepo.getPost(arg);
+    return post.data.commentCount;
+  }
+
+  /// Set the count of comments of the post to [count]. This updates
+  /// the state without needing to fetch the data from the database.
+  void setCount(int count) {
+    state = AsyncValue.data(count);
+  }
+
+  Future<void> refresh() async {
+    state = await AsyncValue.guard(() => build(arg));
+  }
+}
+
+final postCommentCountProvider = AsyncNotifierProvider.autoDispose
+    .family<PostCommentCountViewModel, int, PostIdFirestore>(
+  () => PostCommentCountViewModel(),
+);

lib/viewmodels/user_comments_view_model.dart

@@ -5,6 +5,7 @@ import "package:proxima/models/database/post/post_id_firestore.dart";
 import "package:proxima/models/ui/user_comment_details.dart";
 import "package:proxima/services/database/comment/comment_repository_service.dart";
 import "package:proxima/viewmodels/login_view_model.dart";
+import "package:proxima/viewmodels/post_comment_count_view_model.dart";
 import "package:proxima/viewmodels/posts_feed_view_model.dart";
 
 typedef UserCommentsState = List<UserCommentDetails>;
@@ -53,6 +54,8 @@ class UserCommentViewModel extends AutoDisposeAsyncNotifier<UserCommentsState> {
     // Refresh the home feed after comment deletion, that way the comment
     // count will be updated
     ref.read(postsFeedViewModelProvider.notifier).refresh();
+    // Also update the comment count for the post
+    ref.read(postCommentCountProvider(postId).notifier).refresh();
   }
 
   /// Refresh the list of posts

lib/views/pages/home/content/feed/components/comment_count.dart

@@ -1,17 +1,23 @@
 import "package:flutter/material.dart";
+import "package:hooks_riverpod/hooks_riverpod.dart";
+import "package:proxima/models/database/post/post_id_firestore.dart";
+import "package:proxima/viewmodels/post_comment_count_view_model.dart";
 
 /// This widget is used to display the comment number in the post card.
 /// It contains the comment icon and the number of comments.
-class CommentCount extends StatelessWidget {
-  final int count;
+class CommentCount extends ConsumerWidget {
+  final PostIdFirestore postId;
 
   const CommentCount({
     super.key,
-    required this.count,
+    required this.postId,
   });
 
   @override
-  Widget build(BuildContext context) {
+  Widget build(BuildContext context, WidgetRef ref) {
+    final asyncCount = ref.watch(postCommentCountProvider(postId));
+    final count = asyncCount.valueOrNull ?? 0;
+
     const icon = Icon(Icons.comment, size: 20);
     final countText = Text(count.toString());
 

lib/views/pages/home/content/feed/components/post_card.dart

@@ -79,7 +79,7 @@ class PostCard extends ConsumerWidget {
             onTap: () => _onPostSelect(context, postDetails, ref),
             child: CommentCount(
               key: postCardCommentsNumberKey,
-              count: postDetails.commentNumber,
+              postId: postDetails.postId,
             ),
           ),
         ],

test/end2end/app_actions.dart

@@ -322,11 +322,21 @@ class AppActions {
     await tester.pumpAndSettle();
 
     // Check that the post content is displayed
-    expect(find.text(comment), findsOneWidget);
+    final commentText = find.text(comment);
+    expect(commentText, findsOneWidget);
 
-    // Find the delete button on card
-    final deleteButton = find.byKey(ProfileInfoCard.deleteButtonCardKey);
-    expect(deleteButton, findsOneWidget);
+    // Find and tap the delete button on the card
+    final commentCard = find.ancestor(
+      of: find.text(comment),
+      matching: find.byKey(ProfileInfoCard.infoCardKey),
+    );
+    expect(commentCard, findsOne);
+
+    final deleteButton = find.descendant(
+      of: commentCard,
+      matching: find.byKey(ProfileInfoCard.deleteButtonCardKey),
+    );
+    expect(deleteButton, findsOne);
 
     await tester.tap(deleteButton);
     await tester.pumpAndSettle(delayNeededForAsyncFunctionExecution);

test/end2end/app_test.dart

@@ -11,7 +11,6 @@ import "package:proxima/services/database/firestore_service.dart";
 import "package:proxima/services/sensors/geolocation_service.dart";
 import "package:proxima/views/navigation/bottom_navigation_bar/navigation_bar_routes.dart";
 import "package:proxima/views/pages/home/content/challenge/challenge_list.dart";
-import "package:proxima/views/pages/home/content/feed/post_feed.dart";
 import "package:proxima/views/pages/profile/components/profile_app_bar.dart";
 import "package:proxima/views/proxima_app.dart";
 
@@ -161,17 +160,19 @@ void main() {
     await AppActions.loginToCreateAccount(tester);
     await AppActions.createAccountToHome(tester);
     await AppActions.createPost(tester, testPostTitle, testPostDescription);
-    await AppActions.openPost(tester, testPostTitle);
-    const comment = "I like turtles too!";
-    await AppActions.addComment(tester, comment);
-
-    // back to feed
-    await AppActions.navigateBack(tester);
-    await AppActions.flingRefresh(tester, find.byType(PostFeed));
+    await AppActions.expectCommentCount(tester, testPostTitle, 0);
+
+    // Add two comments
+    const comments = ["I like turtles too!", "I prefer elephants"];
+    for (final (i, comment) in comments.indexed) {
+      await AppActions.openPost(tester, testPostTitle);
+      await AppActions.addComment(tester, comment);
+      await AppActions.navigateBack(tester);
+      await AppActions.expectCommentCount(tester, testPostTitle, i + 1);
+    }
 
-    // expect comment count to be correct
-    AppActions.expectCommentCount(tester, testPostTitle, 1);
-    await AppActions.deleteComment(tester, comment);
-    AppActions.expectCommentCount(tester, testPostTitle, 0);
+    // Deleting a comment should reduce the comment count
+    await AppActions.deleteComment(tester, comments.first);
+    await AppActions.expectCommentCount(tester, testPostTitle, 1);
   });
 }