';
        foreach ($this->ical->filterByDate($date) as $curEvent) {
            $time = $curEvent->getEventTime() ?? 'Ganztags';

            #print_r($curEvent);
            $eventString .= '
' .
                $time . ':
' .
                $curEvent->summary . '
';
        }
        return $eventString;
    }

    /********************* PRIVATE **********************/
    /**
     * create the li element for ul
     */
    private function _showDay($cellNumber)
    {

        if ($this->currentDay == 0) {

            $firstDayOfTheWeek = date('N', strtotime($this->currentYear . '-' . $this->currentMonth . '-01'));

            if (intval($cellNumber) == intval($firstDayOfTheWeek)) {

                $this->currentDay = 1;

            }
        }

        if (($this->currentDay != 0) && ($this->currentDay <= $this->daysInMonth)) {
            $date =
                str_pad($this->currentDay, 2, '0', STR_PAD_LEFT) . '.' .
                str_pad($this->currentMonth, 2, '0', STR_PAD_LEFT) . '.' .
                $this->currentYear;

            $this->currentDate = date('Y-m-d', strtotime($this->currentYear . '-' . $this->currentMonth . '-' . ($this->currentDay)));

            $cellContent = '' . $this->currentDay . '' . $this->getEvent($date);

            $this->currentDay++;

        } else {

            $this->currentDate = null;

            $cellContent = null;
        }


        return '' . $cellContent . '';
    }

    /**
     * create navigation
     */
    private function _createNavi()
    {

        $nextMonth = $this->currentMonth == 12 ? 1 : intval($this->currentMonth) + 1;

        $nextYear = $this->currentMonth == 12 ? intval($this->currentYear) + 1 : $this->currentYear;

        $preMonth = $this->currentMonth == 1 ? 12 : intval($this->currentMonth) - 1;

        $preYear = $this->currentMonth == 1 ? intval($this->currentYear) - 1 : $this->currentYear;

        return
            '
' .
            '<< Vorheriger Monat' .
            '' . $this->monthLabels[(int)date('m', strtotime($this->currentYear . '-' . $this->currentMonth . '-1'))] . ' ' . date('Y', strtotime($this->currentYear . '-' . $this->currentMonth . '-1')) . '' .
            'Nächster Monat >>' .
            '
';
    }

    /**
     * create calendar week labels
     */
    private function _createLabels()
    {

        $content = '';

        foreach ($this->dayLabels as $index => $label) {

            $content .= '' . $label . '';

        }

        return $content;
    }


    /**
     * calculate number of weeks in a particular month
     */
    private function _weeksInMonth($month = null, $year = null)
    {

        if (null == ($year)) {
            $year = date("Y", time());
        }

        if (null == ($month)) {
            $month = date("m", time());
        }

        // find number of days in this month
        $daysInMonths = $this->_daysInMonth($month, $year);

        $numOfweeks = ($daysInMonths % 7 == 0 ? 0 : 1) + intval($daysInMonths / 7);

        $monthEndingDay = date('N', strtotime($year . '-' . $month . '-' . $daysInMonths));

        $monthStartDay = date('N', strtotime($year . '-' . $month . '-01'));

        if ($monthEndingDay < $monthStartDay) {

            $numOfweeks++;

        }

        return $numOfweeks;
    }

    /**
     * calculate number of days in a particular month
     */
    private function _daysInMonth($month = null, $year = null)
    {

        if (null == ($year))
            $year = date("Y", time());

        if (null == ($month))
            $month = date("m", time());

        return date('t', strtotime($year . '-' . $month . '-01'));
    }

}