class MediaSelection

class MediaSelection extends DefaultSelection {
    
    /**
     * {@inheritdoc}
     */
    protected function buildEntityQuery($match = NULL, $match_operator = 'CONTAINS') {
        $query = parent::buildEntityQuery($match, $match_operator);
        // Ensure that users with insufficient permission cannot see unpublished
        // entities.
        if (!$this->currentUser
            ->hasPermission('administer media')) {
            $query->condition('status', 1);
        }
        return $query;
    }
    
    /**
     * {@inheritdoc}
     */
    public function createNewEntity($entity_type_id, $bundle, $label, $uid) {
        $media = parent::createNewEntity($entity_type_id, $bundle, $label, $uid);
        // In order to create a referenceable media, it needs to published.
        
        /** @var \Drupal\media\MediaInterface $media */
        $media->setPublished();
        return $media;
    }
    
    /**
     * {@inheritdoc}
     */
    public function validateReferenceableNewEntities(array $entities) {
        $entities = parent::validateReferenceableNewEntities($entities);
        // Mirror the conditions checked in buildEntityQuery().
        if (!$this->currentUser
            ->hasPermission('administer media')) {
            $entities = array_filter($entities, function ($media) {
                
                /** @var \Drupal\media\MediaInterface $media */
                return $media->isPublished();
            });
        }
        return $entities;
    }

}