private function getPlanningMilestonesByStatus(Planning $planning)
 {
     $user = $this->request->getCurrentUser();
     switch ($this->request->get('period')) {
         case self::PAST_PERIOD:
             return $this->milestone_factory->getAllClosedMilestones($user, $planning);
         case self::FUTURE_PERIOD:
             return $this->milestone_factory->getAllOpenMilestones($user, $planning);
         default:
             return $this->milestone_factory->getAllOpenMilestones($user, $planning);
     }
 }