public function countMedia(CollectionInterface $collection)
{
if (!$collection || !$collection->getId()) {
throw new \InvalidArgumentException();
}
$queryBuilder = $this->createQueryBuilder('collection')->select('COUNT(collectionMedia.id)')->leftJoin('collection.media', 'collectionMedia')->where('collection.id = :id')->setParameter('id', $collection->getId());
return intval($queryBuilder->getQuery()->getSingleScalarResult());
}