Add AbstractController, implement flash message handling, and refactor repositories

src/Repository/CandidateRepository.php

@@ -36,4 +36,13 @@ class CandidateRepository extends ServiceEntityRepository
             ->setParameter('name', $name)
             ->getQuery()->getOneOrNullResult();
     }
+
+    public function save(Candidate $candidate, bool $flush = true): void
+    {
+        $this->getEntityManager()->persist($candidate);
+
+        if (true === $flush) {
+            $this->getEntityManager()->flush();
+        }
+    }
 }

src/Repository/GivenAnswerRepository.php

@@ -17,4 +17,13 @@ class GivenAnswerRepository extends ServiceEntityRepository
     {
         parent::__construct($registry, GivenAnswer::class);
     }
+
+    public function save(GivenAnswer $givenAnswer, bool $flush = true): void
+    {
+        $this->getEntityManager()->persist($givenAnswer);
+
+        if (true === $flush) {
+            $this->getEntityManager()->flush();
+        }
+    }
 }

src/Repository/QuestionRepository.php

@@ -20,13 +20,13 @@ class QuestionRepository extends ServiceEntityRepository
         parent::__construct($registry, Question::class);
     }
 
-    public function findNextQuestionForCandidate(Candidate $candidate): Question
+    public function findNextQuestionForCandidate(Candidate $candidate): ?Question
     {
         $qb = $this->createQueryBuilder('q');
 
         return $qb->join('q.quiz', 'qz')
             ->andWhere($qb->expr()->notIn('q.id', $this->getEntityManager()->createQueryBuilder()
-                ->select('ga.id')
+                ->select('q1')
                 ->from(GivenAnswer::class, 'ga')
                 ->join('ga.answer', 'a')
                 ->join('a.question', 'q1')
@@ -38,6 +38,6 @@ class QuestionRepository extends ServiceEntityRepository
             ->setMaxResults(1)
             ->setParameter('candidate', $candidate)
             ->setParameter('quiz', $candidate->getSeason()->getActiveQuiz())
-        ->getQuery()->getSingleResult();
+        ->getQuery()->getOneOrNullResult();
     }
 }