class AlterUserActivities < ActiveRecord::Migration
  def up
    count = UserActivity.all.count / 30 + 3
    transaction do
      for i in 1 ... count do i
        UserActivity.page(i).per(30).each do |activity|
          if activity.act_type == 'Message'
            if activity.act
              unless activity.act.parent_id.nil?
                parent_act = UserActivity.where("act_id = #{activity.act.parent.id} and act_type='Message'").first
                parent_act.created_at = activity.act.parent.children.maximum("created_on")
                parent_act.save
                activity.destroy
              end
            else
              activity.destroy
            end
          end
        end
      end
    end
  end

  def down
  end
end