<?php
/**
 * Yahoo Geocoder for US Cities
 *
 * @author Jan Bruyndonckx
 * @copyright Copyright (c) 2008 Banzora   http://software.banzora.com
 * @package main
 * @subpackage lib
 *
*/

	require_once "Geocoder.inc";

	/**
		Class to geocode a US location.
		The location is specified using the zip code, the cityname and the state
		The zip code has precedence.
		We use the Yahoo geocoder described at:
		http://developer.yahoo.net/maps/rest/V1/geocode.html
	*/

	class USGeocoder extends Geocoder
	{
		const SERVICE_URL = "http://api.local.yahoo.com/MapsService/V1/geocode?" ;
		const APPLICATION_ID = "tripticdesign" ;

		/**--------------------------------------------------------------------
			Perform the query to the internet service provider.
			Return NULL in case of error, or an xml text
		*/
		protected function createRequest () {
			$url=USGeocoder::SERVICE_URL . "appid=" . USGeocoder::APPLICATION_ID ;
			if ($this->zipcode != NULL)
			{
					$url = $url . "&zip=" . $this->zipcode ;
			}
			if ($this->city != NULL)
			{
					$url = $url . "&city=" . $this->city ;
			}
			if ($this->state != NULL)
			{
					$url = $url . "&state=" . $this->state ;
			}

            return $url ;
        }

		/**--------------------------------------------------------------------
			Parses a result that looks like:
			<ResultSet>
			<Result precision="zip+4">
			<Latitude>37.4196</Latitude>
			<Longitude>-122.0298</Longitude>
			<Address></Address>
			<City>SUNNYVALE</City>
			<State>CA</State>
			<Zip>94089-1019</Zip>
			<Country>US</Country>
			</Result>
			</ResultSet>
		*/
		public function parseResult ($result)
		{
			$dom = new DOMDocument() ;
			$dom->preserveWhiteSpace = false ;
			$result = $dom->loadXML ($result) ;
			if ($result == false)
			{
					return NULL ;    // $result should be valid xml
			}

			$latitudelist = $dom->getElementsByTagName ("Latitude") ;
			if ($latitudelist->length != 1)
			{
					return NULL ;    // location has one latitude only
			}
			$longitudelist = $dom->getElementsByTagName ("Longitude") ;
			if ($longitudelist->length != 1)
			{
					return NULL ;    // location has one longitude only
			}

            return $this->createResult ($longitudelist->item(0)->textContent,
                                 $latitudelist->item(0)->textContent) ;
		}
 	}
// end class USGeocoder

?>