fixes #2197

app/models/forum_topic_visit.rb

@@ -0,0 +1,30 @@
+class ForumTopicVisit < ActiveRecord::Base
+  def self.check!(user, topic)
+    match = where(:user_id => user.id, :forum_topic_id => topic.id).first
+    result = false
+    if match
+      if match.last_read_at < topic.updated_at
+        result = true
+      end
+      match.update_attribute(:last_read_at, topic.updated_at)
+    else
+      create(:user_id => user.id, :forum_topic_id => topic.id, :last_read_at => topic.updated_at)
+    end
+    result
+  end
+
+  def self.check_list!(user, topics)
+    matches = where(:user_id => user.id, :forum_topic_id => topics.map(&:id)).to_a.inject({}) do |hash, x|
+      hash[x.forum_topic_id] = x
+      hash
+    end
+    topics.each do |topic|
+      if matches[topic.id]
+        matches[topic.id].update_attribute(:last_read_at, topic.updated_at)
+      else
+        create(:user_id => user.id,, :forum_topic_id => topic.id, :last_read_at => topic.updated_at)
+      end
+    end
+    matches
+  end
+end