++ Railsflavored

module HasOneMilestone
  # Notice: has_many_polymorphs are creating two associations for the base
  # class including this module, for example TaskList.
  # 1) has_many :schedules
  # 2) has_many :milestones, :through => :schedules
  #
  # This module wraps the has_many relationship and looks more like a has_one
  # relationship.  It's sort of like
  #    has_one :milestone, :through => :schedules, :polymorphic => true

  def milestone=(milestone)
    transaction do 
      self.schedules = []
      self.milestones << milestone if milestone
    end
  end
  
  def milestone(reload = false)
    self.milestones.first if self.milestones(reload)
  end
  
  # This method must be called for milestone associations to be saved.  This is 
  # because the record id must be generated before it can be associated with 
  # a milestone.
  def commit_milestone
    self.milestone = Milestone.find(@milestone_id) unless @milestone_id.blank?
  end

end