FIX: more reliable topic list counts

- unread was not incrementing when you read last post on topic
- new notifications were being inserted even if they existed in list
- terminology was all mixed up "1 new posts", split to 3 messages
- latest behaves as expected, updating count of new and updated topics

app/assets/javascripts/discourse/helpers/i18n_helpers.js

@@ -54,7 +54,7 @@ Ember.Handlebars.registerHelper('countI18n', function(key, options) {
     shouldRerender: Discourse.View.renderIfChanged('count'),
 
     render: function(buffer) {
-      buffer.push(I18n.t(key, { count: this.get('count') }));
+      buffer.push(I18n.t(key + (this.get('suffix') || ""), { count: this.get('count') }));
     }
 
   });

app/assets/javascripts/discourse/models/topic_tracking_state.js

@@ -17,13 +17,17 @@ Discourse.TopicTrackingState = Discourse.Model.extend({
         tracker.incrementMessageCount();
       }
 
-      if (data.message_type === "new_topic"){
+      if (data.message_type === "new_topic" || data.message_type === "latest") {
         var ignored_categories = Discourse.User.currentProp("muted_category_ids");
         if(_.include(ignored_categories, data.payload.category_id)){
           return;
         }
       }
 
+      if (data.message_type === "latest"){
+        tracker.notify(data);
+      }
+
       if (data.message_type === "new_topic" || data.message_type === "unread" || data.message_type === "read") {
         tracker.notify(data);
         var old = tracker.states["t" + data.topic_id];
@@ -36,6 +40,7 @@ Discourse.TopicTrackingState = Discourse.Model.extend({
     };
 
     Discourse.MessageBus.subscribe("/new", process);
+    Discourse.MessageBus.subscribe("/latest", process);
     var currentUser = Discourse.User.current();
     if(currentUser) {
       Discourse.MessageBus.subscribe("/unread/" + currentUser.id, process);
@@ -55,17 +60,29 @@ Discourse.TopicTrackingState = Discourse.Model.extend({
     if (!this.newIncoming) { return; }
 
     if ((this.filter === "all" ||this.filter === "latest" || this.filter === "new") && data.message_type === "new_topic" ) {
-      this.newIncoming.push(data.topic_id);
+      this.addIncoming(data.topic_id);
     }
-    if ((this.filter === "all" ||this.filter === "latest" || this.filter === "unread") && data.message_type === "unread") {
+
+    if ((this.filter === "all" || this.filter === "unread") && data.message_type === "unread") {
       var old = this.states["t" + data.topic_id];
-      if(!old) {
+      if(!old || old.highest_post_number === old.last_read_post_number) {
-        this.newIncoming.push(data.topic_id);
+        this.addIncoming(data.topic_id);
       }
     }
+
+    if(this.filter === "latest" && data.message_type === "latest") {
+      this.addIncoming(data.topic_id);
+    }
+
     this.set("incomingCount", this.newIncoming.length);
   },
 
+  addIncoming: function(topicId) {
+    if(this.newIncoming.indexOf(topicId) === -1){
+      this.newIncoming.push(topicId);
+    }
+  },
+
   resetTracking: function(){
     this.newIncoming = [];
     this.set("incomingCount", 0);

app/assets/javascripts/discourse/templates/discovery/topics.js.handlebars

@@ -67,8 +67,8 @@
           <tr>
             <td colspan="9">
               <div class='alert alert-info clickable' {{action showInserted}}>
-                {{countI18n new_topics_inserted count=topicTrackingState.incomingCount}}
+                {{countI18n topic_count_ suffix=topicTrackingState.filter count=topicTrackingState.incomingCount}}
-                {{i18n show_new_topics}}
+                {{i18n click_to_show}}
               </div>
             </td>
           </tr>

app/assets/javascripts/discourse/templates/mobile/discovery/topics.js.handlebars

@@ -12,8 +12,8 @@
           <tr>
             <td>
               <div class='alert alert-info' {{action showInserted}}>
-                {{countI18n new_topics_inserted countBinding="topicTrackingState.incomingCount"}}
+                {{countI18n topic_count_ suffix=topicTrackingState.filter count=topicTrackingState.incomingCount}}
-                {{i18n show_new_topics}}
+                {{i18n click_to_show}}
               </div>
             </td>
           </tr>

app/assets/javascripts/discourse/views/topic.js.es6

@@ -117,6 +117,11 @@ export default Discourse.View.extend(AddCategoryClass, Discourse.Scrolling, {
     @method scrolled
   **/
   scrolled: function(){
+
+    if(this.isDestroyed || this.isDestroying) {
+      return;
+    }
+
     var offset = window.pageYOffset || $('html').scrollTop();
     if (!this.get('docAt')) {
       var title = $('#topic-title');

app/models/topic_tracking_state.rb

@@ -37,6 +37,23 @@ class TopicTrackingState
     publish_read(topic.id, 1, topic.user_id)
   end
 
+  def self.publish_latest(topic)
+    return unless topic.archetype == "regular"
+
+    message = {
+      topic_id: topic.id,
+      message_type: "latest",
+      payload: {
+        bumped_at: topic.bumped_at,
+        topic_id: topic.id,
+        category_id: topic.category_id
+      }
+    }
+
+    group_ids = topic.category && topic.category.secure_group_ids
+    MessageBus.publish("/latest", message.as_json, group_ids: group_ids)
+  end
+
   def self.publish_unread(post)
     # TODO at high scale we are going to have to defer this,
     #   perhaps cut down to users that are around in the last 7 days as well

config/locales/client.en.yml

@@ -150,8 +150,19 @@ en:
       last_read: "this is the last post you've read; click to bookmark it"
       remove: "Remove Bookmark"
 
-    new_topics_inserted: "{{count}} new posts."
+    topic_count_latest:
-    show_new_topics: "Click to show."
+      one: "{{count}} new or updated topic."
+      other: "{{count}} new or updated topics."
+
+    topic_count_unread:
+      one: "{{count}} unread topic."
+      other: "{{count}} unread topics."
+
+    topic_count_new:
+      one: "{{count}} new topic."
+      other: "{{count}} new topics."
+
+    click_to_show: "Click to show."
     preview: "preview"
     cancel: "cancel"
 

lib/post_jobs_enqueuer.rb

@@ -30,6 +30,7 @@ class PostJobsEnqueuer
 
   def after_post_create
     TopicTrackingState.publish_unread(@post) if @post.post_number > 1
+    TopicTrackingState.publish_latest(@topic)
 
     Jobs.enqueue_in(
         SiteSetting.email_time_window_mins.minutes,

lib/post_revisor.rb

@@ -82,6 +82,7 @@ class PostRevisor
   def bump_topic
     unless Post.where('post_number > ? and topic_id = ?', @post.post_number, @post.topic_id).exists?
       @post.topic.update_column(:bumped_at, Time.now)
+      TopicTrackingState.publish_latest(@post.topic)
     end
   end