fix: adjust detection of overlapping applications

addresses #869ar02xk

src/Repository/ApplicationRepository.php

@@ -8,6 +8,7 @@ use App\Entity\Teamer;
 use App\Model\ApplicationFilterDto;
 use App\Model\AssignmentFilterDto;
 use App\Repository\Traits\QueryHelperTrait;
+use Carbon\CarbonPeriod;
 use Doctrine\Bundle\DoctrineBundle\Repository\ServiceEntityRepository;
 use Doctrine\ORM\Query;
 use Doctrine\Persistence\ManagerRegistry;
@@ -161,6 +162,67 @@ class ApplicationRepository extends ServiceEntityRepository
         ;
     }
 
+    /**
+     * Finds all applications of a teamer whose effective assignment period overlaps the given period.
+     *
+     * The effective period of an assignment is its own date range, falling back to the date range of
+     * its destination whenever the assignment does not override it - the query mirrors
+     * {@see Assignment::getEffectivePeriod()}. Boundaries count as an overlap: a teamer cannot end one
+     * assignment on the same day another one begins.
+     *
+     * @return array<Application>
+     */
+    public function findOverlappingForTeamer(Teamer $teamer, CarbonPeriod $period): array
+    {
+        return $this
+            ->getOverlappingForTeamerQuery($teamer, $period)
+            ->getResult()
+        ;
+    }
+
+    public function getOverlappingForTeamerQuery(Teamer $teamer, CarbonPeriod $period): Query
+    {
+        $qb = $this->createQueryBuilder('application');
+
+        return $qb
+            ->innerJoin('application.assignment', 'assignment')
+            ->innerJoin('assignment.destination', 'destination')
+            ->where($qb->expr()->andX(
+                $qb->expr()->eq('application.teamer', ':teamer'),
+                $qb->expr()->neq('application.status', ':application_rejected'),
+                $qb->expr()->neq('assignment.status', ':assignment_called_off'),
+                $qb->expr()->isNull('assignment.deletedAt'),
+                $qb->expr()->isNull('destination.deletedAt'),
+                $qb->expr()->orX(
+                    $qb->expr()->andX(
+                        $qb->expr()->isNull('assignment.dateFrom'),
+                        $qb->expr()->lte('destination.dateFrom', ':dateTo')
+                    ),
+                    $qb->expr()->andX(
+                        $qb->expr()->isNotNull('assignment.dateFrom'),
+                        $qb->expr()->lte('assignment.dateFrom', ':dateTo')
+                    )
+                ),
+                $qb->expr()->orX(
+                    $qb->expr()->andX(
+                        $qb->expr()->isNull('assignment.dateTo'),
+                        $qb->expr()->gte('destination.dateTo', ':dateFrom')
+                    ),
+                    $qb->expr()->andX(
+                        $qb->expr()->isNotNull('assignment.dateTo'),
+                        $qb->expr()->gte('assignment.dateTo', ':dateFrom')
+                    )
+                )
+            ))
+            ->setParameter('teamer', $teamer)
+            ->setParameter('application_rejected', Application::STATUS_REJECTED)
+            ->setParameter('assignment_called_off', Assignment::STATUS_CALLED_OFF)
+            ->setParameter('dateFrom', $period->start->toDateTimeImmutable())
+            ->setParameter('dateTo', $period->end->toDateTimeImmutable())
+            ->getQuery()
+        ;
+    }
+
     public function getCurrentByAssignment(Assignment $assignment): array
     {
         $qb = $this->createQueryBuilder('application');