FEATURE: reorder participants in topic so always chronological

FEATURE: tie breaker for same number of posts is last post date
UX: highlight for latest poster when it is OP

app/assets/stylesheets/desktop/topic-list.scss

@@ -108,7 +108,16 @@
       }
     }
   }
-  
+
+  .posters a:first-child .avatar.latest:not(.single) {
+     box-shadow: 0 0 3px 1px desaturate(scale-color($tertiary, $lightness: 65%), 35%);
+     border: 2px solid desaturate(scale-color($tertiary, $lightness: 50%), 40%);
+     position: relative;
+     top: -2px;
+     left: -2px;
+  }
+
+
   .sortable {
     cursor: pointer;
     &:hover {

app/models/post_mover.rb

@@ -43,6 +43,7 @@ class PostMover
     update_user_actions
     set_last_post_user_id(destination_topic)
 
+    destination_topic.reload
     destination_topic
   end
 

app/models/topic_featured_users.rb

@@ -11,10 +11,8 @@ class TopicFeaturedUsers
 
   # Chooses which topic users to feature
   def choose(args={})
-    clear
-    update keys(args)
+    self.class.ensure_consistency!(topic.id.to_i)
     update_participant_count
-    topic.save
   end
 
   def user_ids
@@ -24,19 +22,29 @@ class TopicFeaturedUsers
      topic.featured_user4_id].uniq.compact
   end
 
-  def self.ensure_consistency!
+  def self.ensure_consistency!(topic_id=nil)
 
     sql = <<SQL
 
 WITH cte as (
     SELECT
-        t.id, p.user_id,
-        ROW_NUMBER() OVER(PARTITION BY t.id ORDER BY COUNT(*) DESC) as rank
+        t.id,
+        p.user_id,
+        MAX(p.created_at) last_post_date,
+        ROW_NUMBER() OVER(PARTITION BY t.id ORDER BY COUNT(*) DESC, MAX(p.created_at) DESC) as rank
     FROM topics t
     JOIN posts p ON p.topic_id = t.id
-    WHERE p.deleted_at IS NULL AND NOT p.hidden AND p.user_id <> t.user_id AND
+    WHERE p.deleted_at IS NULL AND
+          NOT p.hidden AND
+          p.user_id <> t.user_id AND
           p.user_id <> t.last_post_user_id
     GROUP BY t.id, p.user_id
+),
+
+cte2 as (
+  SELECT id, user_id, ROW_NUMBER() OVER(PARTITION BY id ORDER BY last_post_date ASC) as rank
+  FROM cte
+  WHERE rank <= #{count}
 )
 
 UPDATE topics tt
@@ -52,8 +60,7 @@ FROM (
       MAX(case when c.rank = 2 then c.user_id end) featured_user2,
       MAX(case when c.rank = 3 then c.user_id end) featured_user3,
       MAX(case when c.rank = 4 then c.user_id end) featured_user4
-  FROM cte as c
-  WHERE c.rank <= 4
+  FROM cte2 as c
   GROUP BY c.id
 ) x
 WHERE x.id = tt.id AND
@@ -62,7 +69,7 @@ WHERE x.id = tt.id AND
   COALESCE(featured_user2_id,-99) <> COALESCE(featured_user2,-99) OR
   COALESCE(featured_user3_id,-99) <> COALESCE(featured_user3,-99) OR
   COALESCE(featured_user4_id,-99) <> COALESCE(featured_user4,-99)
-)
+) #{"AND x.id = #{topic_id.to_i}" if topic_id}
 SQL
 
     Topic.exec_sql(sql)
@@ -70,30 +77,7 @@ SQL
 
   private
 
-    def keys(args)
-      # Don't include the OP or the last poster
-      to_feature = topic.posts.where('user_id NOT IN (?, ?)', topic.user_id, topic.last_post_user_id)
-
-      # Exclude a given post if supplied (in the case of deletes)
-      to_feature = to_feature.where("id <> ?", args[:except_post_id]) if args[:except_post_id].present?
-
-      # Assign the featured_user{x} columns
-      to_feature.group(:user_id).order('count_all desc').limit(TopicFeaturedUsers.count).count.keys
-    end
-
-    def clear
-      TopicFeaturedUsers.count.times do |i|
-        topic.send("featured_user#{i+1}_id=", nil)
-      end
-    end
-
-    def update(user_keys)
-      user_keys.each_with_index do |user_id, i|
-        topic.send("featured_user#{i+1}_id=", user_id)
-      end
-    end
-
     def update_participant_count
-      topic.participant_count = topic.posts.count('distinct user_id')
+      topic.update_columns(participant_count: topic.posts.count('distinct user_id'))
     end
 end

app/services/post_owner_changer.rb

@@ -19,6 +19,7 @@ class PostOwnerChanger
 
       @topic.update_statistics
       @new_owner.user_stat.update(first_post_created_at: @new_owner.posts(true).order('created_at ASC').first.try(:created_at))
+      @topic.save!
     end
   end
 end

lib/post_destroyer.rb

@@ -72,7 +72,6 @@ class PostDestroyer
       if @post.topic
         make_previous_post_the_last_one
         clear_user_posted_flag
-        feature_users_in_the_topic
         Topic.reset_highest(@post.topic_id)
       end
       trash_public_post_actions
@@ -92,6 +91,7 @@ class PostDestroyer
       TopicUser.update_post_action_cache(topic_id: @post.topic_id)
     end
 
+    feature_users_in_the_topic if @post.topic
     @post.publish_change_to_clients! :deleted if @post.topic
   end
 
@@ -136,7 +136,7 @@ class PostDestroyer
   end
 
   def feature_users_in_the_topic
-    Jobs.enqueue(:feature_topic_users, topic_id: @post.topic_id, except_post_id: @post.id)
+    Jobs.enqueue(:feature_topic_users, topic_id: @post.topic_id)
   end
 
   def trash_public_post_actions

spec/components/post_destroyer_spec.rb

@@ -291,7 +291,7 @@ describe PostDestroyer do
     let!(:post) { Fabricate(:post, raw: "Hello @CodingHorror") }
 
     it "should feature the users again (in case they've changed)" do
-      Jobs.expects(:enqueue).with(:feature_topic_users, has_entries(topic_id: post.topic_id, except_post_id: post.id))
+      Jobs.expects(:enqueue).with(:feature_topic_users, has_entries(topic_id: post.topic_id))
       PostDestroyer.new(moderator, post).destroy
     end
 

spec/jobs/feature_topic_users_spec.rb

@@ -30,11 +30,6 @@ describe Jobs::FeatureTopicUsers do
       expect(topic.reload.featured_user_ids.include?(coding_horror.id)).to eq(true)
     end
 
-    it "will not feature the second poster if we supply their post to be ignored" do
-      Jobs::FeatureTopicUsers.new.execute(topic_id: topic.id, except_post_id: second_post.id)
-      expect(topic.reload.featured_user_ids.include?(coding_horror.id)).to eq(false)
-    end
-
     it "won't feature the last poster" do
       Jobs::FeatureTopicUsers.new.execute(topic_id: topic.id)
       expect(topic.reload.featured_user_ids.include?(evil_trout.id)).to eq(false)