/* Gets querystring variables */
function getQueryVariable(variable) { 
  var query = window.location.search.substring(1); 
  var vars = query.split("&"); 
  for (var i=0;i<vars.length;i++) { 
    var pair = vars[i].split("="); 
    if (pair[0] == variable) { 
      return pair[1]; 
    } 
  } 
} 

/**
* Returns an XMLHttp instance to use for asynchronous
* downloading. This method will never throw an exception, but will
* return NULL if the browser does not support XmlHttp for any reason.
* @return {XMLHttpRequest|Null}
*/
function createXmlHttpRequest() {
 try {
   if (typeof ActiveXObject != 'undefined') {
     return new ActiveXObject('Microsoft.XMLHTTP');
   } else if (window["XMLHttpRequest"]) {
     return new XMLHttpRequest();
   }
 } catch (e) {
   changeStatus(e);
 }
 return null;
};

/**
* This functions wraps XMLHttpRequest open/send function.
* It lets you specify a URL and will call the callback if
* it gets a status code of 200.
* @param {String} url The URL to retrieve
* @param {Function} callback The function to call once retrieved.
*/
function downloadUrl(url, callback) {
 var status = -1;
 var request = createXmlHttpRequest();
 if (!request) {
   return false;
 }

 request.onreadystatechange = function() {
   if (request.readyState == 4) {
     try {
       status = request.status;
     } catch (e) {
       // Usually indicates request timed out in FF.
     }
     if ((status == 200) || (status == 0)) {
       callback(request.responseText, request.status);
       request.onreadystatechange = function() {};
     }
   }
 }
 request.open('GET', url, true);
 try {
   request.send(null);
 } catch (e) {
   changeStatus(e);
 }
};

/**
 * Parses the given XML string and returns the parsed document in a
 * DOM data structure. This function will return an empty DOM node if
 * XML parsing is not supported in this browser.
 * @param {string} str XML string.
 * @return {Element|Document} DOM.
 */
function xmlParse(str) {
  if (typeof ActiveXObject != 'undefined' && typeof GetObject != 'undefined') {
    var doc = new ActiveXObject('Microsoft.XMLDOM');
    doc.loadXML(str);
    return doc;
  }

  if (typeof DOMParser != 'undefined') {
    return (new DOMParser()).parseFromString(str, 'text/xml');
  }

  return createElement('div', null);
}

/**
 * Appends a JavaScript file to the page.
 * @param {string} url
 */
function downloadScript(url) {
  var script = document.createElement('script');
  script.src = url;
  document.body.appendChild(script);
}

//<![CDATA[
      // this variable will collect the html which will eventually be placed in the side_bar 
      var side_bar_html = ""; 
    
      // arrays to hold copies of the markers and html used by the side_bar 
      // because the function closure trick doesnt work there 
      var gmarkers = []; 

     // global "map" variable
      var map = null;
// A function to create the marker and set up the event window function 
function createMarker(latlng, name, html, count) {
    var contentString = html;

	var image = new google.maps.MarkerImage("images/markers/" + count + ".png",
        new google.maps.Size(34.0, 28.0),
        new google.maps.Point(0, 0),
        new google.maps.Point(17.0, 28.0)
    );
     
	var shadow = new google.maps.MarkerImage("images/markers/shadow.png",
        new google.maps.Size(49.0, 28.0),
        new google.maps.Point(0, 0),
        new google.maps.Point(17.0, 28.0)
    );
    
    var marker = new google.maps.Marker({
        position: latlng,
        map: map,
        title: name,
        icon: image,
        shadow: shadow,
        zIndex: Math.round(latlng.lat()*-100000)<<5
        });

    google.maps.event.addListener(marker, 'click', function() {
        infowindow.setContent(contentString); 
//        infowindow.width(350);
//        infowindow.height(250);
        infowindow.open(map,marker);
        });
    // save the info we need to use later for the side_bar
    gmarkers.push(marker);
    // add a line to the side_bar html
    side_bar_html += '<a href="javascript:myclick(' + (gmarkers.length-1) + ')">' + name + '<\/a><br>';
}

 
// This function picks up the click and opens the corresponding info window
function myclick(i) {
  google.maps.event.trigger(gmarkers[i], "click");
}

function initialize() {
  // create the map
  var myOptions = {
    zoom: 3,
    center: new google.maps.LatLng(0, 20),
    mapTypeControl: true,
    mapTypeControlOptions: {style: google.maps.MapTypeControlStyle.DROPDOWN_MENU},
    navigationControl: true,
    mapTypeId: google.maps.MapTypeId.ROADMAP
  }
  map = new google.maps.Map(document.getElementById("map_canvas"),
                                myOptions);
 
  google.maps.event.addListener(map, 'click', function() {
        infowindow.close();
        });
      // Read the data from example.xml
      downloadUrl("rss.map.xml.php?t=" + getQueryVariable("t") + "&l=" + getQueryVariable("l"), function(doc) {
//		downloadUrl("tempmarker.xml", function(doc) {
        var xmlDoc = xmlParse(doc);
        var markers = xmlDoc.documentElement.getElementsByTagName("marker");
        for (var i = 0; i < markers.length; i++) {
          // obtain the attribues of each marker
          var lat = parseFloat(markers[i].getAttribute("lat"));
          var lng = parseFloat(markers[i].getAttribute("lng"));
          var point = new google.maps.LatLng(lat,lng);
          var html = markers[i].getAttribute("html");
          var label = markers[i].getAttribute("label");
          var count = markers[i].getAttribute("count");
          // create the marker
          var marker = createMarker(point,label,html,count);
        }
        // put the assembled side_bar_html contents into the side_bar div
//        document.getElementById("side_bar").innerHTML = side_bar_html;
      });
    }
 
var infowindow = new google.maps.InfoWindow(
  { 
    size: new google.maps.Size(150,50)
  });
    

    // This Javascript is based on code provided by the
    // Community Church Javascript Team
    // http://www.bisphamchurch.org.uk/   
    // http://econym.org.uk/gmap/
    // from the v2 tutorial page at:
    // http://econym.org.uk/gmap/basic3.htm 
//]]>