/**
* Gets UID of a calendar this event belongs to
* The calendar UID is a string includes a calendar alias and id in the following format: {alias}_{id}
*
* @return string|null
*/
public function getCalendarUid()
{
if ($this->calendar) {
return sprintf('%s_%d', Calendar::CALENDAR_ALIAS, $this->calendar->getId());
} elseif ($this->systemCalendar) {
$alias = $this->systemCalendar->isPublic() ? SystemCalendar::PUBLIC_CALENDAR_ALIAS : SystemCalendar::CALENDAR_ALIAS;
return sprintf('%s_%d', $alias, $this->systemCalendar->getId());
}
return null;
}
