FIX: chat activity indicator wasn't working for threads

When a user had the chat option "Show activity indicator in header" set to "all new messages", and they would get a reply to a thread they're part of, the chat icon in the header would not show the unread bubble indicator.

In order to fix this, the `ChatHeaderIconUnreadIndicator` component will now `showUnreadIndicator` whenever there is either one unread public channel or there are unread threads.

I only added a system spec for this very specific path because I don't want to slow down the whole suite to test for all the various combination of the `chat_header_indicator_preference` values.

Internal ref - t/128874

plugins/chat/app/models/chat/user_chat_channel_membership.rb

@@ -13,6 +13,10 @@ module Chat
     enum :desktop_notification_level, NOTIFICATION_LEVELS, prefix: :desktop_notifications
     enum :mobile_notification_level, NOTIFICATION_LEVELS, prefix: :mobile_notifications
     enum :join_mode, { manual: 0, automatic: 1 }
+
+    def mark_read!(new_last_read_id = nil)
+      update!(last_read_message_id: new_last_read_id || chat_channel.last_message_id)
+    end
   end
 end
 

plugins/chat/assets/javascripts/discourse/components/chat/header/icon/unread-indicator.gjs

@@ -34,6 +34,12 @@ export default class ChatHeaderIconUnreadIndicator extends Component {
     );
   }
 
+  get hasUnreads() {
+    return (
+      this.unreadCount > 0 || this.chatTrackingStateManager.hasUnreadThreads
+    );
+  }
+
   get indicatorPreference() {
     return (
       this.args.indicatorPreference ||
@@ -57,7 +63,7 @@ export default class ChatHeaderIconUnreadIndicator extends Component {
 
   get showUnreadIndicator() {
     return (
-      this.unreadCount > 0 &&
+      this.hasUnreads &&
       this.#hasAnyIndicatorPreference([HEADER_INDICATOR_PREFERENCE_ALL_NEW])
     );
   }

plugins/chat/spec/system/message_notifications_with_sidebar_spec.rb

@@ -5,14 +5,21 @@ RSpec.describe "Message notifications - with sidebar", type: :system do
 
   let!(:chat_page) { PageObjects::Pages::Chat.new }
   let!(:channel_page) { PageObjects::Pages::ChatChannel.new }
+  let!(:thread_page) { PageObjects::Pages::ChatThread.new }
 
   before do
     SiteSetting.navigation_menu = "sidebar"
     chat_system_bootstrap
   end
 
-  def create_message(text: nil, channel:, creator: Fabricate(:user))
-    Fabricate(:chat_message_with_service, chat_channel: channel, message: text, user: creator)
+  def create_message(text: nil, channel: nil, thread: nil, creator: Fabricate(:user))
+    Fabricate(
+      :chat_message_with_service,
+      chat_channel: channel,
+      thread: thread,
+      message: text,
+      user: creator,
+    )
   end
 
   context "as a user" do
@@ -225,6 +232,40 @@ RSpec.describe "Message notifications - with sidebar", type: :system do
           end
         end
       end
+
+      context "with a thread" do
+        fab!(:channel) { Fabricate(:category_channel, threading_enabled: true) }
+        fab!(:other_user) { Fabricate(:user) }
+        fab!(:thread) do
+          chat_thread_chain_bootstrap(channel: channel, users: [current_user, other_user])
+        end
+
+        before do
+          channel.membership_for(current_user).mark_read!
+          thread.membership_for(current_user).mark_read!
+
+          visit("/")
+        end
+
+        context "when chat_header_indicator_preference is 'all_new'" do
+          before do
+            current_user.user_option.update!(
+              chat_header_indicator_preference:
+                UserOption.chat_header_indicator_preferences[:all_new],
+            )
+          end
+
+          context "when a reply is created" do
+            it "shows the unread indicator in the header" do
+              expect(page).to have_no_css(".chat-header-icon .chat-channel-unread-indicator")
+
+              create_message(thread: thread, creator: other_user)
+
+              expect(page).to have_css(".chat-header-icon .chat-channel-unread-indicator")
+            end
+          end
+        end
+      end
     end
   end
 end

plugins/chat/spec/system/message_thread_indicator_spec.rb

@@ -6,10 +6,8 @@ describe "Thread indicator for chat messages", type: :system do
 
   let(:chat_page) { PageObjects::Pages::Chat.new }
   let(:channel_page) { PageObjects::Pages::ChatChannel.new }
-  let(:thread_page) { PageObjects::Pages::ChatThread.new }
   let(:side_panel) { PageObjects::Pages::ChatSidePanel.new }
   let(:open_thread) { PageObjects::Pages::ChatThread.new }
-  let(:chat_drawer_page) { PageObjects::Pages::ChatDrawer.new }
 
   before do
     chat_system_bootstrap(current_user, [channel])