Zabbix

<?php

/*

** Copyright (C) 2001-2025 Zabbix SIA

**

** This program is free software: you can redistribute it and/or modify it under the terms of

** the GNU Affero General Public License as published by the Free Software Foundation, version 3.

**

** This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;

** without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

** See the GNU Affero General Public License for more details.

**

** You should have received a copy of the GNU Affero General Public License along with this program.

** If not, see <https://www.gnu.org/licenses/>.

**/

​

/**

 * Date and time helper.

 */

class CDateTimeHelper {

​

    /**

     * Check if time zone observe the daylight saving time.

     *

     * @param string $timezone      time-zone name

     *

     * @return boolean

     */

    public static function isDaylightSavingTime($timezone) {

        $zone = new DateTimeZone($timezone);

        $time = time();

        $transition = $zone->getTransitions($time, $time);

​

        return $transition[0]['isdst'];

    }

​

    /**

     * Get the UTC offset for a specific time zone.

     *

     * @param string $timezone      time-zone name

     *

     * @return string

     */

    public static function getUTCOffset($timezone) {

        $offset = (strtotime('now UTC') - strtotime('now '.$timezone));

        $sign = $offset >= 0 ? '+' : '-';

        $offset = abs($offset);

​

        return sprintf('UTC%s%02d:%02d', $sign, $offset / 3600, ($offset / 60) % 60);

    }

​

    /**

     * Get time zone with UTC time usable as label in time-zone drop-downs.

     *

     * @param string $label     time zone name or default value of time-zone dropdown

     *

     * @return string

     */

    public static function getTimeZoneFormat($label) {

        $timezone = ($label === 'System' || $label === 'System default') ? 'Europe/Riga' : $label;

        $utc = CDateTimeHelper::getUTCOffset($timezone);

​

        return (($label === 'System' || $label === 'System default') ? $label .': ': '').'('.$utc.') '.$timezone;

    }

​

    /**

     * The days are counted from specific date and time period.

     *

     * @param string $date      timestamp

     * @param string $period    time period

     *

     * @return int

     */

    public static function countDays($date = 'now', $period = 'P1Y') {

        $to = new DateTime($date);

        $from = (clone $to)->sub(new DateInterval($period));

​

        return $from->diff($to)->days;

    }

​

    /**

     * Get the time difference in months between two moments in time.

     *

     * @param string|int    $from       timestamp or string that represents the oldest moments in time

     * @param string|int    $to         timestamp or string that represents the newest moments in time

     *

     * @return int

     */

    public static function countMonthsBetweenDates($from, $to = 'now') {

        foreach ([&$from, &$to] as &$moment) {

            if (is_string($moment)) {

                $moment = strtotime($moment);