Communication: Fix mentioned users recieving notifications in convers…

…ations they are not part of (#9814)

src/main/java/de/tum/cit/aet/artemis/communication/service/notifications/ConversationNotificationService.java

@@ -41,11 +41,15 @@ public class ConversationNotificationService {
 
     private final SingleUserNotificationRepository singleUserNotificationRepository;
 
+    private final SingleUserNotificationService singleUserNotificationService;
+
     public ConversationNotificationService(ConversationNotificationRepository conversationNotificationRepository,
-            GeneralInstantNotificationService generalInstantNotificationService, SingleUserNotificationRepository singleUserNotificationRepository) {
+            GeneralInstantNotificationService generalInstantNotificationService, SingleUserNotificationRepository singleUserNotificationRepository,
+            SingleUserNotificationService singleUserNotificationService) {
         this.conversationNotificationRepository = conversationNotificationRepository;
         this.generalInstantNotificationService = generalInstantNotificationService;
         this.singleUserNotificationRepository = singleUserNotificationRepository;
+        this.singleUserNotificationService = singleUserNotificationService;
     }
 
     /**
@@ -83,7 +87,7 @@ public ConversationNotification createNotification(Post createdMessage, Conversa
         String[] placeholders = createPlaceholdersNewMessageChannelText(course.getTitle(), createdMessage.getContent(), createdMessage.getCreationDate().toString(),
                 conversationName, createdMessage.getAuthor().getName(), conversationType);
         ConversationNotification notification = createConversationMessageNotification(course.getId(), createdMessage, notificationType, notificationText, true, placeholders);
-        save(notification, mentionedUsers, placeholders);
+        save(notification, mentionedUsers, placeholders, createdMessage);
         return notification;
     }
 
@@ -93,11 +97,12 @@ public static String[] createPlaceholdersNewMessageChannelText(String courseTitl
         return new String[] { courseTitle, messageContent, messageCreationDate, conversationName, authorName, conversationType };
     }
 
-    private void save(ConversationNotification notification, Set<User> mentionedUsers, String[] placeHolders) {
+    private void save(ConversationNotification notification, Set<User> mentionedUsers, String[] placeHolders, Post createdMessage) {
         conversationNotificationRepository.save(notification);
 
-        Set<SingleUserNotification> mentionedUserNotifications = mentionedUsers.stream().map(mentionedUser -> SingleUserNotificationFactory
-                .createNotification(notification.getMessage(), NotificationType.CONVERSATION_USER_MENTIONED, notification.getText(), placeHolders, mentionedUser))
+        Set<SingleUserNotification> mentionedUserNotifications = singleUserNotificationService
+                .filterAllowedRecipientsInMentionedUsers(mentionedUsers, createdMessage.getConversation()).map(mentionedUser -> SingleUserNotificationFactory
+                        .createNotification(notification.getMessage(), NotificationType.CONVERSATION_USER_MENTIONED, notification.getText(), placeHolders, mentionedUser))
                 .collect(Collectors.toSet());
         singleUserNotificationRepository.saveAll(mentionedUserNotifications);
     }

src/main/java/de/tum/cit/aet/artemis/communication/service/notifications/SingleUserNotificationService.java

@@ -443,23 +443,34 @@ public void notifyInvolvedUsersAboutNewMessageReply(Post post, SingleUserNotific
             usersInvolved.add(post.getAuthor());
         }
 
-        mentionedUsers.stream().filter(user -> {
-            boolean isChannelAndCourseWide = post.getConversation() instanceof Channel channel && channel.getIsCourseWide();
-            boolean isChannelVisibleToStudents = !(post.getConversation() instanceof Channel channel) || conversationService.isChannelVisibleToStudents(channel);
-            boolean isChannelVisibleToMentionedUser = isChannelVisibleToStudents
-                    || authorizationCheckService.isAtLeastTeachingAssistantInCourse(post.getConversation().getCourse(), user);
-
-            // Only send a notification to the mentioned user if...
-            // (for course-wide channels) ...the course-wide channel is visible
-            // (for all other cases) ...the user is a member of the conversation
-            return (isChannelAndCourseWide && isChannelVisibleToMentionedUser) || conversationService.isMember(post.getConversation().getId(), user.getId());
-        }).forEach(mentionedUser -> notifyUserAboutNewMessageReply(savedAnswerMessage, notification, mentionedUser, author, CONVERSATION_USER_MENTIONED));
+        filterAllowedRecipientsInMentionedUsers(mentionedUsers, post.getConversation())
+                .forEach(mentionedUser -> notifyUserAboutNewMessageReply(savedAnswerMessage, notification, mentionedUser, author, CONVERSATION_USER_MENTIONED));
 
         Conversation conv = conversationService.getConversationById(post.getConversation().getId());
         usersInvolved.stream().filter(userInvolved -> !mentionedUsers.contains(userInvolved))
                 .forEach(userInvolved -> notifyUserAboutNewMessageReply(savedAnswerMessage, notification, userInvolved, author, getAnswerMessageNotificationType(conv)));
     }
 
+    /**
+     * Filters which of the mentioned users are permitted to receive a notification
+     *
+     * @param mentionedUsers users mentioned in the answer message
+     * @param conversation   the conversation of the created post/notification, used for filtering
+     * @return the stream of mentioned users which are permitted to receive the notification for the given conversation
+     */
+    public Stream<User> filterAllowedRecipientsInMentionedUsers(Set<User> mentionedUsers, Conversation conversation) {
+        return mentionedUsers.stream().filter(user -> {
+            boolean isChannelAndCourseWide = conversation instanceof Channel channel && channel.getIsCourseWide();
+            boolean isChannelVisibleToStudents = !(conversation instanceof Channel channel) || conversationService.isChannelVisibleToStudents(channel);
+            boolean isChannelVisibleToMentionedUser = isChannelVisibleToStudents || authorizationCheckService.isAtLeastTeachingAssistantInCourse(conversation.getCourse(), user);
+
+            // Only send a notification to the mentioned user if...
+            // (for course-wide channels) ...the course-wide channel is visible
+            // (for all other cases) ...the user is a member of the conversation
+            return (isChannelAndCourseWide && isChannelVisibleToMentionedUser) || conversationService.isMember(conversation.getId(), user.getId());
+        });
+    }
+
     /**
      * Saves the given notification in database and sends it to the client via websocket.
      * Also creates and sends an instant notification.