FEATURE: Topic timeline widget

lib/timeline_lookup.rb

@@ -0,0 +1,26 @@
+module TimelineLookup
+
+  # Given an array of tuples (id, post_number, days_ago), return at most `max_values` worth of a
+  # lookup table to help the front end timeline display dates associated with posts
+  def self.build(tuples, max_values=300)
+    result = []
+
+    every = (tuples.size.to_f / max_values).ceil
+
+    last_days_ago = -1
+    tuples.each_with_index do |t, idx|
+      next unless (idx % every) === 0
+
+      _, post_number, days_ago = t
+
+      if (days_ago != last_days_ago)
+        result << [post_number, days_ago]
+        last_days_ago = days_ago
+      end
+
+    end
+
+    result
+  end
+
+end

lib/topic_view.rb

@@ -311,7 +311,6 @@ class TopicView
     @filtered_posts.by_newest.with_user.first(25)
   end
 
-
   def current_post_ids
     @current_post_ids ||= if @posts.is_a?(Array)
       @posts.map {|p| p.id }
@@ -320,8 +319,17 @@ class TopicView
     end
   end
 
+  # Returns an array of [id, post_number, days_ago] tuples. `days_ago` is there for the timeline
+  # calculations.
+  def filtered_post_stream
+    @filtered_post_stream ||= @filtered_posts.order(:sort_order)
+                                             .pluck(:id,
+                                                    :post_number,
+                                                    'EXTRACT(DAYS FROM CURRENT_TIMESTAMP - created_at)::INT AS days_ago')
+  end
+
   def filtered_post_ids
-    @filtered_post_ids ||= filter_post_ids_by(:sort_order)
+    @filtered_post_ids ||= filtered_post_stream.map {|tuple| tuple[0]}
   end
 
   protected
@@ -435,11 +443,6 @@ class TopicView
     raise Discourse::InvalidAccess.new("can't see #{@topic}", @topic) unless guardian.can_see?(@topic)
   end
 
-
-  def filter_post_ids_by(sort_order)
-    @filtered_posts.order(sort_order).pluck(:id)
-  end
-
   def get_minmax_ids(post_number)
     # Find the closest number we have
     closest_index = closest_post_to(post_number)