class Rufus::Scheduler::EveryJob

def determine_at
  return unless @frequency
  @last = @at
    # the first time, @last will be nil
  now = Time.now.to_f
  @at = if @last
    @last + @frequency
  else
    if fi = @params[:first_in]
      now + Rufus.duration_to_f(fi)
    elsif fa = @params[:first_at]
      Rufus.at_to_f(fa)
    else
      now + @frequency
    end
  end
  while @at < now do
    @at += @frequency
  end if @params[:discard_past]
end