Event::checkUserReadAccess

static function checkUserReadAccess(array $params): bool
{
	$eventId = (int)$params['eventId'];
	if(
		!$eventId
		|| !Loader::includeModule('calendar')
	)
	{
		return false;
	}

	$events = CCalendarEvent::getList(
		[
			'arFilter' => [
				'ID' => $eventId,
				'DELETED' => false,
			],
			'parseRecursion' => false,
			'fetchAttendees' => true,
			'checkPermissions' => true,
			'setDefaultLimit' => false
		]
	);

	return ($events && is_array($events[0]));
}