/**
* Create a (readable) filename for the certificate
*
* @return string
*/
protected function createFilename()
{
$ref_id = $this->definition->getRefId();
$obj_title = ilObject::_lookupTitle(ilObject::_lookupObjectId($ref_id));
$user_name = $this->getUser()->getLastname() . '-' . $this->getUser()->getFirstname();
$filename_elements = array(date('Y-m-d', strtotime($this->getValidFrom())), $this->sanitizeStr($user_name), $this->sanitizeStr($obj_title));
$filename = implode('-', $filename_elements);
$filename = rtrim($filename, '-');
return $filename . '.pdf';
}
