<?php
	/**
	* This class accepts a street address and attempts to return lat/long coordinates using the Google Maps API.
	* @author Richard Sharp
	* @copyright 2007
	* @version 1.0
	* @package Location
	*/
	
	class GoogleGeocoder
	{
		/**
		* Sets the API Key issued by Google.
		*	@var string
		*/
		var $Key="";
		
		/**
		* Sets the street address to geocode. If the address is not broken down into street, city, state, etc, put the entire address in this field.
		*	@var string
		*/
		var $Address="";
		
		/**
		* Sets the city to geocode.
		*	@var string
		*/
		var $City="";
		
		/**
		* Sets the state to geocode.
		*	@var string
		*/
		var $State="";
		
		/**
		* Sets the country to geocode.
		*	@var string
		*/
		var $Country="US";
		
		/**
		* Sets the zip code to geocode.
		*	@var string
		*/
		var $Zip="";
		
		/**
		* Gets the raw request sent to Google.
		*	@var string
		*/
		var $LastRequest="";
		
		/**
		* Gets the raw response received from Google.
		*	@var string
		*/
		var $LastResponse;
		
		 /**
		 * Constructor for the class.
		 * @param string The Google API key.
		 * @return void
		 */ 
		// class constructor
		// $Key - the Google API key for this site
		function GoogleGeocoder($Key)
		{
			$this->Key=$Key;
		}
		
		 /**
		 * Submits the address to Google and processes the response.
		 * @return mixed On success, returns an array containing two elements: Latitude and Longitude. Returns false on failure.
		 */ 
		function GeoCode()
		{
			$objCurl = curl_init(); 
			
			//build the parameters into the URL
			$url="http://maps.google.com/maps/geo?q=".urlencode($this->Address).",+".urlencode($this->City).",+".urlencode($this->State).",+".$this->Country."&output=csv&key=".$this->Key;
			
			//Submit the request to Google
			$this->LastRequest=$url;
			curl_setopt($objCurl, CURLOPT_POST,1); 
			curl_setopt($objCurl, CURLOPT_URL,$url); 
			curl_setopt($objCurl, CURLOPT_RETURNTRANSFER,1); 
			curl_setopt($objCurl, CURLOPT_SSL_VERIFYPEER, FALSE); 
			$LastResponse = curl_exec ($objCurl);
			$this->LastResponse=$LastResponse;
			curl_close ($objCurl); 
			
			//if successful, the response will be in this format: Specificity, Location, Latitude, Longitude
			if(strpos($LastResponse,",")>0)
			{
				$dLatitude=0;
				$dLongitude=0;
				$return_parts=explode("\n",$LastResponse);
				//there may be multiple rows returned. the last is the most accurate. loop through backwards until we find a positive response (200)
				while(($last_row=array_pop($return_parts)) && !$dLatitude)
				{
					$row_parts=explode(",",$last_row);
					if($row_parts[0]==200) //200 is the specificity we want
					{
						$dLatitude=$row_parts[2];
						$dLongitude=$row_parts[3];
					}
				}
			}
			return(array("Latitude"=>$dLatitude,"Longitude"=>$dLongitude));
		}
	}
?>