/**
  * @subscribe
  * @param User $user
  * @param ScalarExercise $exercise
  */
 public function onCorrectAnswer(User $user, ScalarExercise $exercise)
 {
     $blueprint = $exercise->getBlueprint();
     // TODO award after percentage on last N answers reaches X %
     if ($user->getBadges($this->getKey())->where('blueprint_id = ?', $blueprint->id)->count() !== 0) {
         // already awarded for this blueprint
         return;
     }
     $this->awardTo($user, function (Badge $badge, User $user) use($blueprint) {
         return new Bridges\ExerciseMastery($badge, $user, $blueprint);
     });
 }
 /**
  * @subscribe
  * @param User $user
  */
 public function onLogin(User $user)
 {
     if ($user->getBadges($this->getKey())->count() !== 0) {
         // already awarded
         return;
     }
     if ($user->createdAt < DateTime::from('-1 week')) {
         $this->awardTo($user, function (Badge $badge, User $user) {
             return new Bridges\UserOldWeek($badge, $user);
         });
     }
 }