CTimeManUser::isDayOpenedToday

public function isDayOpenedToday()
{
	// server time at the moment of day start
	$ts_start = !empty(CTimeManUser::$LAST_ENTRY[$this->USER_ID]['DATE_START']) ? (MakeTimeStamp(CTimeManUser::$LAST_ENTRY[$this->USER_ID]['DATE_START']) - CTimeZone::GetOffset()) : time();
	$ts_start_day = MakeTimeStamp(ConvertTimeStamp($ts_start, 'SHORT'));

	// server time that was at the day start
	$time_start = $ts_start - $ts_start_day;

	// server timezone diff with server that was at the day start
	$timezone_diff = CTimeManUser::$LAST_ENTRY[$this->USER_ID]['TIME_START'] - $time_start;

	// current date with such timezone_diff;
	$t = time();
	$date_current = date('Y-m-d', $t + $timezone_diff);
	$date_current_day = date('Y-m-d', $ts_start_day);

	return $date_current == $date_current_day;
}