<?php

namespace Da\User\Helper;

use DateTimeZone;
use yii\helpers\ArrayHelper;
use DateTime;

class TimezoneHelper
{
    /**
     * Get all of the time zones with the offsets sorted by their offset.
     *
     * @return array
     */
    public static function getAll()
    {
        $timeZones = [];
        $timeZoneIdentifiers = DateTimeZone::listIdentifiers();

        foreach ($timeZoneIdentifiers as $timeZone) {
            $date = new DateTime('now', new DateTimeZone($timeZone));
            $offset = $date->getOffset() / 60 / 60;
            $timeZones[] = [
                'timezone' => $timeZone,
                'name' => "{$timeZone} (UTC ".($offset > 0 ? '+' : '')."{$offset})",
                'offset' => $offset,
            ];
        }

        ArrayHelper::multisort($timeZones, 'offset', SORT_DESC, SORT_NUMERIC);

        return $timeZones;
    }
}