Helper::getIcalTemplateRRule

static function getIcalTemplateRRule(array $rrule = null, array $params = null): string
{
	$res = '';
	if ($rrule['BYDAY'] ?? false)
	{
		$rrule['BYDAY'] = CCalendarEvent::sortByDay($rrule['BYDAY']);
	}
	switch($rrule['FREQ'] ?? null)
	{
		case 'DAILY':
			$res = (int)$rrule['INTERVAL'] === 1
				? Loc::getMessage('EC_RRULE_EVERY_DAY')
				: Loc::getMessage('EC_RRULE_EVERY_DAY_1', ['#DAY#' => $rrule['INTERVAL']])
			;
			break;
		case 'WEEKLY':
			if (!isset($rrule['BYDAY']) || !is_array($rrule['BYDAY']))
			{
				$rrule['BYDAY'] = ['MO'];
			}

			$daysList = implode(', ', array_map(static function($day) {return Loc::getMessage('EC_' . $day);}, $rrule['BYDAY']));
			$res = (int)$rrule['INTERVAL'] === 1
				? Loc::getMessage('EC_RRULE_EVERY_WEEK', ['#DAYS_LIST#' => $daysList])
				: Loc::getMessage('EC_RRULE_EVERY_WEEK_1', ['#WEEK#' => $rrule['INTERVAL'], '#DAYS_LIST#' => $daysList])
			;
			break;
		case 'MONTHLY':
			$res = (int)$rrule['INTERVAL'] === 1
				? Loc::getMessage('EC_RRULE_EVERY_MONTH')
				: Loc::getMessage('EC_RRULE_EVERY_MONTH_1', ['#MONTH#' => $rrule['INTERVAL']])
			;
			break;
		case 'YEARLY':
			$fromTs = CCalendar::Timestamp($params['DATE_FROM']);
			$res = (int)$rrule['INTERVAL'] === 1
				? Loc::getMessage('EC_RRULE_EVERY_YEAR', [
					'#DAY#' => FormatDate('j', $fromTs),
					'#MONTH#' => FormatDate('n', $fromTs)
				])
				: Loc::getMessage('EC_RRULE_EVERY_YEAR_1', [
					'#YEAR#' => $rrule['INTERVAL'],
					'#DAY#' => FormatDate('j', $fromTs),
					'#MONTH#' => FormatDate('n', $fromTs)
				])
			;
			break;
	}

	if ($rrule['COUNT'] ?? false)
	{
		$res .= ' ' . Loc::getMessage('EC_RRULE_COUNT', ['#COUNT#' => $rrule['COUNT']]);
	}
	elseif (isset($rrule['UNTIL']) && $rrule['UNTIL'] && self::isNotEndOfTime($rrule['UNTIL']))
	{
		$res .= ' ' . Loc::getMessage('EC_RRULE_UNTIL', ['#UNTIL_DATE#' => $rrule['UNTIL']]);
	}

	return $res;
}