<?php
/* OSGB grid ref converter 
 * 
 * Pre-pends SE if required (i.e. optimised for West Yorkshire)
 *
 * Place the perl scripts in assets/snippets/osgb/
 * 
 * $OSGBgridref is 6, 8 or 10 figure grid reference, optionally prefixed with the letters
 * denoting the 100km grid square (defaults to SE).
 *
 * OSGBgridref() returns a numerically indexed array with 0=>latitude and 1=>longitude.
 * Gmap_...      returns a javascript call that creates a Google Map GLatLng object
 */

if (!function_exists(OSGBgridref))
	{
	function OSGBgridref($OSGBgridref)
	        {
		/* Trim whitespace */
		$OSGBgridref = str_replace(' ', '',$OSGBgridref);
	
		/* Pre-pend SE if required */
		if (ctype_digit($OSGBgridref)) $OSGBgridref='SE'.$OSGBgridref;
	
		/* Convert 8 and 10 figure grid refs to 6-figure) */
		if(strlen($OSGBgridref)==10) $OSGBgridref = substr($OSGBgridref, 0, 5).substr($OSGBgridref, 6, 3);
		elseif (strlen($OSGBgridref)==12) $OSGBgridref = substr($OSGBgridref, 0, 5).substr($OSGBgridref, 7, 3);
	
	        if (ereg('^[[:alpha:]]{2}[[:digit:]]{6}$',$OSGBgridref))
	                {
	                $OSGBresult =  explode (' ', shell_exec('cd '.MODX_BASE_PATH.'assets/snippets/osgb/ && perl osgb.pl '.$OSGBgridref));
			$OSGBresult[0] = trim($OSGBresult[0]);
	        	$OSGBresult[1] = trim($OSGBresult[1]);
        		if (sizeof($OSGBresult) == 2 && is_numeric($OSGBresult[0]) &&  is_numeric($OSGBresult[1]))
	            	        return $OSGBresult;
	                else
	               	        return array(0, 0);
	                }
	        else
			return array(0,0);
		}
        }

if (!function_exists(Gmap_OSGBgridref))
	{
	function Gmap_OSGBgridref($OSGBgridref)
		{
		$OSGBlatlong = OSGBgridref($OSGBgridref);
		return "new GLatLng({$OSGBlatlong[0]}, {$OSGBlatlong[1]})";
		}
	}
	
return Gmap_OSGBgridref($OSGBgridref);
?>