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