DateConverter::getDateOfDayOfCurrentWeek

static function getDateOfDayOfCurrentWeek($nameOfday, BitrixMainTypeDateTime $date = null)
{
	$date = $date? $date: new BitrixMainTypeDateTime();

	$nameOfday = mb_strtoupper($nameOfday);
	if (!in_array($nameOfday, Array('MONDAY', 'TUESDAY', 'WEDNESDAY', 'THURSDAY', 'FRIDAY', 'SATURDAY', 'SUNDAY')))
		return false;

	$relation = '';
	$day = $date->format('N');
	if (
		$nameOfday == 'MONDAY' && $day == 1 ||
		$nameOfday == 'TUESDAY' && $day <= 2 ||
		$nameOfday == 'WEDNESDAY' && $day <= 3 ||
		$nameOfday == 'THURSDAY' && $day <= 4 ||
		$nameOfday == 'FRIDAY' && $day <= 5 ||
		$nameOfday == 'SATURDAY' && $day <= 6 ||
		$nameOfday == 'SUNDAY' && $day <= 7
	)
	{
		$relation = 'THIS';
	}
	$date->add($relation.' '.$nameOfday);

	return $date;
}