// MapManager Class

function MapManager (divMap, dataUrl) {
    this.divMap = divMap;
    this.dataUrl = dataUrl;      
    this.markers = [];
    this.map = null;
    //this.infowindow = new google.maps.InfoWindow();
    
    this.showMap = function() { 
        var latlng = new google.maps.LatLng(41.126001, 16.8683788);
        var myOptions = { zoom: 6, center: latlng, mapTypeId: google.maps.MapTypeId.ROADMAP, scrollwheel: false };
        this.map = new google.maps.Map(document.getElementById(this.divMap), myOptions);
        
        google.maps.event.addListener(this.map, 'click', function() {
            this.infowindow.close();
            });
            
        this.downloadData();
    }

    this.downloadData = function downloadData() {
        this.clearOverlays();
        downloadUrl(
            dataUrl + "&dummy=" + new Date().getTime(), 
            function(doc, status, obj) {
                var xmlDoc = xmlParse(doc);
                var xmlRoot = xmlDoc.documentElement;
                var xmlMarkers = xmlRoot.getElementsByTagName("marker");
                if (xmlMarkers)
                {
                    for (var i = 0; i < xmlMarkers.length; i++) {
                        obj.createMarker(xmlMarkers[i]);
                    }
                    if (xmlMarkers.length > 1) {
                        obj.zoomToFitMarkers();
                    }
                }
            },
            this
        );
    }
    
    this.createMarker = function (xmlMarker) {
        var name = xmlMarker.getAttribute("name");
        var url = xmlMarker.getAttribute("url");
        var selected = xmlMarker.getAttribute("selected") == "true";
        var lat = parseFloat(xmlMarker.getAttribute("lat"));
        var lng = parseFloat(xmlMarker.getAttribute("lng")); 
        var latlng = new google.maps.LatLng(lat, lng);
        
        var image = xmlMarker.getAttribute("image");
        var width = parseInt(xmlMarker.getAttribute("width"));
        var height = parseInt(xmlMarker.getAttribute("height"));
        
        var icon = null;
        var shadow = null;
        
        if (selected)
        {
            icon = new google.maps.MarkerImage(WEBSITE_BASEPATH + "images/marker-selected.png",
                              new google.maps.Size(32, 32),   // size
                              new google.maps.Point(0,0),     // origin
                              new google.maps.Point(16, 32)); // anchor
                              
            shadow = new google.maps.MarkerImage(WEBSITE_BASEPATH + "images/marker-shadow.png",
                              new google.maps.Size(38, 34),   // size
                              new google.maps.Point(0,0),     // origin
                              new google.maps.Point(12, 34)); // anchor
        }
        else if (image != null) 
        {
            icon = new google.maps.MarkerImage(image,
                              new google.maps.Size(width, height),   // size
                              new google.maps.Point(0,0),     // origin
                              new google.maps.Point(width/2, height/2)); // anchor
        }
        else
        {
            icon = new google.maps.MarkerImage(WEBSITE_BASEPATH + "images/marker.png",
                              new google.maps.Size(32, 32),   // size
                              new google.maps.Point(0,0),     // origin
                              new google.maps.Point(16, 32)); // anchor
                              
            shadow = new google.maps.MarkerImage(WEBSITE_BASEPATH + "images/marker-shadow.png",
                              new google.maps.Size(38, 34),   // size
                              new google.maps.Point(0,0),     // origin
                              new google.maps.Point(12, 34)); // anchor
        }

        var marker = new google.maps.Marker({
            position: latlng,
            map: this.map,
            zIndex: Math.round(latlng.lat()*-100000)<<5,
            title: name,
            icon: icon,
            shadow: shadow
            });
        
        /*
        if (selected)
        {
            this.infowindow.setContent('<div style="width: 50px; height: 20px; color: #f00">' + marker.title + '</div>'); 
            this.infowindow.open(this.map, marker);
        }
        */
        
        google.maps.event.addListener(marker, 'click', function() {
            document.location.href = url;
            });
        
        this.markers.push(marker);
    }

    this.clearOverlays = function () {
        for (var i = 0; i < this.markers.length; i++) {
            this.markers[i].setMap(null);
        }
        this. markers = [];
    }

    this.zoomToFitMarkers = function () {
        var bounds = new google.maps.LatLngBounds();
        for (var i = 0; i < this.markers.length; i++) {
          bounds.extend (this.markers[i].getPosition());
        }
        this.map.fitBounds(bounds);
    }
}

// Funzioni per il download di XML

/**
* 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, obj) {
 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, obj);
       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);
}