CDavICalendarTimeZone::ParseDateTime

static function ParseDateTime($text, $tzid = false, CDavICalendar $calendar = null)
{
	$arDateParts = explode('T', $text);
	$notZ = true;

	if (!empty($text) && count($arDateParts) !== 2)
	{
		if (!preg_match('/^(d{4}-?d{2}-?d{2})(Z)?$/', $text, $match))
		{
			return $text;
		}

		$arDateParts = explode('T', $match[1] . 'T000000' . ($match[2] ?? ''));
	}

	if (($arDate = self::ParseDate($arDateParts[0])) == null)
	{
		return $text;
	}
	if (($arTime = self::ParseTime($arDateParts[1])) == null)
	{
		return $text;
	}

	$tzoffset = false;
	if ($calendar && $tzid)
	{
		$tzoffset = self::GetVTimezoneOffset($arDate, $arTime, $tzid, $calendar);
		$notZ = false;
	}

	$result = @mktime($arTime["hours"], $arTime["minutes"], $arTime["seconds"], $arDate["month"], $arDate["mday"], $arDate["year"]);

	if ($tzoffset)
	{
		$result += $tzoffset;
	}

/*		if ($arTime["zone"] == 'UTC' || $tzoffset !== false)
	{
		$result = @gmmktime($arTime["hours"], $arTime["minutes"], $arTime["seconds"], $arDate["month"], $arDate["mday"], $arDate["year"]);
		if ($tzoffset)
			$result -= $tzoffset;
	}
	else
	{
		$result = @mktime($arTime["hours"], $arTime["minutes"], $arTime["seconds"], $arDate["month"], $arDate["mday"], $arDate["year"]);
	}*/

	if ($notZ && ($arTime["zone"] !== 'Local' || $tzid))
	{
		$result += date('Z');
	}

	return ($result !== false) ? $result : $text;
}