var map;
var elemDetails=new Array();
var elemTrack=new Array();
var polyline_id=null;
var polyline_w=null;
function GPXParser(xmlDoc)
{
	this.xmlDoc = xmlDoc;
}
GPXParser.prototype.getTrackpoints = function ()
{
	var tracks = this.xmlDoc.documentElement.getElementsByTagName("trk");
	var points = new Array(); 
	for (var i=0; i < tracks.length; i++)
	{
		var track = tracks[i];
		var segments = track.getElementsByTagName("trkseg");
		for (var i=0; i < segments.length; i++)
		{
			var trackSegment = segments[i];
			var trackpoints = trackSegment.getElementsByTagName("trkpt");
			if (trackpoints.length == 0) {
				continue;
			}
			for (var i=0; i < trackpoints.length; i++)
			{
				var lon = parseFloat(trackpoints[i].getAttribute("lon"));
				var lat = parseFloat(trackpoints[i].getAttribute("lat"));
				points.push(new google.maps.LatLng(lat,lon));
			}
		}
	}
	return points;
}
function initGGMaps()
{
	directionsDisplay = new google.maps.DirectionsRenderer();
	geocoder = new google.maps.Geocoder();
	var latlng = new google.maps.LatLng(46.830134,1.7570801);
	var options = {
		mapTypeControl: true,
		navigationControl: true,
		center: latlng,
		mapTypeId: google.maps.MapTypeId.TERRAIN
	};
	map = new google.maps.Map(document.getElementById("map_canvas"), options);
	loadTrack();
}
function loadTrack(idTrace) {
	var xhr_object = null;
	if(window.XMLHttpRequest) {
		// Firefox
	   xhr_object = new XMLHttpRequest();
	   xhr_object.overrideMimeType('text/xml');
	}
	else if(window.ActiveXObject)
		// IE
	   xhr_object = new ActiveXObject("Microsoft.XMLHTTP");
	if(xhr_object != null)
	{
		xhr_object = new XMLHttpRequest();
		xhr_object.onreadystatechange = function()
		{
			if (xhr_object.readyState == 4) {
				//Chargement OK
				var parser = new GPXParser(xhr_object.responseXML);
				var data = parser.getTrackpoints();
				elemTrack[idTrace]=data;
				displayTrack(idTrace);
			}
		};
		xhr_object.open("GET", "" , true);
		xhr_object.send(null);
	}
}
function displayTrack(elemid) {
	if (elemTrack[elemid]) {
		displayTrackImpl(elemid);
	} else {
		loadTrack(elemid);
	}
}
function displayTrackImpl(elemid) {
  if (polyline_w) {
      polyline_w.setMap(null);
      polyline_w=null;
    }
		//line params
    var lineColor="#0033FF";
    var polyline = new google.maps.Polyline({
		path: elemTrack[elemid],
		strokeColor: lineColor,
		strokeOpacity: 0.8,
		strokeWeight: 4
    });
    polyline.setMap(map);
    polyline_id=elemid;
    polyline_w=polyline;
    map.fitBounds(getBounds(elemTrack[elemid]));
}
function getBounds(latLngArray) {
	var i;
	var minLat = latLngArray[0].lat();
	var maxLat = latLngArray[0].lat();
	var minLng = latLngArray[0].lng();
	var maxLng = latLngArray[0].lng();
	for (i=1 ; i<latLngArray.length ; i++) {
		var ll=latLngArray[i];
		if (minLat > ll.lat()) 
			minLat = ll.lat();
		else if (maxLat < ll.lat()) 
			maxLat = ll.lat();
		if (minLng > ll.lng()) 
			minLng = ll.lng();
		else if (maxLng < ll.lng()) 
			maxLng = ll.lng();
	}
	var ne = new google.maps.LatLng(minLat,minLng);
	var sw = new google.maps.LatLng(maxLat,maxLng);
	return new google.maps.LatLngBounds(ne,sw);
}