fixes #858

adds color coding to both urls and other names on artist versions

app/models/artist_version.rb

@@ -27,6 +27,36 @@ class ArtistVersion < ActiveRecord::Base
     url_string.scan(/\S+/)
   end
 
+  def other_names_array
+    other_names.scan(/\S+/)
+  end
+
+  def urls_diff(version)
+    new_urls = url_array
+    old_urls = version.present? ? version.url_array : []
+
+    return {
+      :added_urls => new_urls - old_urls,
+      :removed_urls => old_urls - new_urls,
+      :unchanged_urls => new_urls & old_urls,
+    }
+  end
+
+  def other_names_diff(version)
+    new_names = other_names_array
+    old_names = version.present? ? version.other_names_array : []
+
+    return {
+      :added_names => new_names - old_names,
+      :removed_names => old_names - new_names,
+      :unchanged_names => new_names & old_names,
+    }
+  end
+
+  def previous
+    ArtistVersion.where("artist_id = ? and updated_at < ?", artist_id, updated_at).order("updated_at desc").first
+  end
+
   def updater_name
     User.id_to_name(updater_id).tr("_", " ")
   end