public function getUserRegistrations(User $user, array $collections)
    {
        $qb = $this->createQueryBuilder('d');
        $qb->where($qb->expr()->eq('d.user', ':user'));
        $qb->setParameter(':user', $user->getId());

        if (count($collections) > 0) {
            $qb->andWhere('d.baseId IN (:bases)');
            $qb->setParameter(':bases', array_map(function (\collection $collection) {
                return $collection->get_base_id();
            }, $collections));
        }

        $qb->orderBy('d.created', 'DESC');

        return $qb->getQuery()->getResult();
    }