<?php
  /**
   * Copyright (c) 2012 Georg Ehrke <ownclouddev at georgswebsite dot de>
   * This file is licensed under the Affero General Public License version 3 or
   * later.
   * See the COPYING-README file.
   */
  class OC_Geo{
  	/*
  	 * @brief returns the closest timezone to coordinates
  	 * @param (string) $latitude - Latitude
  	 * @param (string) $longitude - Longitude
  	 * @return (string) $timezone - closest timezone
  	 */
  	public static function timezone($latitude, $longitude) {
  		$alltimezones = DateTimeZone::listIdentifiers();
  		$variances = array();
  		//calculate for all timezones the system know
  		foreach($alltimezones as $timezone) {
  			$datetimezoneobj = new DateTimeZone($timezone);
  			$locationinformations = $datetimezoneobj->getLocation();
  			$latitudeoftimezone = $locationinformations['latitude'];
  			$longitudeoftimezone = $locationinformations['longitude'];
  			$variances[abs($latitudeoftimezone - $latitude) + abs($longitudeoftimezone - $longitude)] = $timezone;
  		}
  		//sort array and return the timezone with the smallest difference
  		ksort($variances);
  		reset($variances);
  		return current($variances);
  	}

  }