gistfile1.rbx

 # makes sure that all of the monsters and characters have participants
  def update_participants
    epm = {}
    # make sure each character is accounted for, each one is only in there once.
    self.participants.each do |p|
      unless p.is_monster? || self.characters.include?(p.character)
        self.add_participants([p], :type => :character)
      elsif p.is_monster?
        epm[p.monster_id] = epm[p.monster_id] ? 0 : epm[p.monster_id] + 1  # build a monster count hash
      end
    end
    
    # make sure each monster is accounted for, this is tougher since there can be more than one.
    # strategy: monster lists can only grow here, they are deleted elsewhere
    self.monster_ids.each do |mid|
      # if the monster is in the emp list, decrement it
      if (emp[mid] && emp[mid] > 0) 
        emp[mid] -= 1
      else # otherwise, add it (inefficiently one at a time, meh)
        self.add_participants([Monster.find(mid)], :type => :monster)
      end
    end
  end