role_profile_gmap = new function(){

  // Create global variables

  var map;

  var marker;

  var geocoder;

  // The following strings can be customized to reflect ids in the page. 

  // You can also add or remove fields used for GMap Geocoding in 

  // the JSON address object

  var current_lat = 0;

  var current_lng = 0;

  // Two different levels for zoom: Starting one and an inner that 

  // is used when showing the map if lat and lon page fields are set

  var world_zoom = 0;

  var country_zoom = 4;

  var state_zoom = 6;

  var city_zoom = 10;

  var postalcode_zoom = 12;

  // Do not add a starting # as this JQuery selector seems 

  // incompatible with GMap API

  var map_div = "role_profile_map";

  var field_lat = "#id_latitude";

  var field_lng = "#id_longitude";

  // Need to save old values to avoid unwanted updating 

  // of lat and lot if marker dragged and blur another time an address field

  var address = {

    city: {

      id: "#id_res_city",

      old_value: ""

    },

    state: {

      id: "#id_res_state",

      old_value: ""

    },

    country: {

      id: "#id_res_country",

      old_value: ""

    },

    postalcode: {

      id: "#id_res_postalcode",

      old_value: ""

    }

  }

  // Save current address fields in the JSON Object

  function saveOldAddress() {

    for (var a in address) {

      address[a].old_value = $(address[a].id).val();

    }

  }

  // Return true if the user has edited address fields

  function isNewAddress() {

    for (var a in address) {

      if ($(address[a].id).val() != address[a].old_value) return true;

    }

    return false;

  }

  // Write saved lat and lng values to page fields

  function setLatLngFields() {

    $(field_lat).val(current_lat);

    $(field_lng).val(current_lng);

  }

  // Read lat and lng fields and store them

  function readLatLngFields() {

    current_lat = $(field_lat).val();

    current_lng = $(field_lng).val();

  }

  // This function reads address fields, merge them and uses 

  // GMap API geocoding to find the first hit

  // Using geocoding http://code.google.com/intl/it-IT/apis/maps/documentation/services.html#Geocoding

  function calculateAddress() {

    // If the user has really edited address fields...

    if (isNewAddress()) {

      // Merge address fields

      var address_string = "";

      for (var a in address) {

        address_string+=$(address[a].id).val();

        if (a!=address.length-1) {address_string+=","};

      }

      // Ask GMap API for geocoding

      geocoder.getLatLng(

        address_string,

        function(point) {

          // If a point is found

          if (point) {

            // Save the current address in the JSON object

            saveOldAddress();

            // Set the new zoom, map center and marker coords

            var zoom_set = world_zoom;

            if ($(address.postalcode.id).val()!="") zoom_set = postalcode_zoom;

            else if ($(address.city.id).val()!="") zoom_set = city_zoom;

            else if ($(address.state.id).val()!="") zoom_set = state_zoom;

            else if ($(address.country.id).val()!="") zoom_set = country_zoom;

            map.setCenter(point, zoom_set);

            marker.setPoint(point);

            map.clearOverlays();

            map.addOverlay(marker);

            // Save point coords in local variables and then update 

            // the page lat/lng fields

            current_lat = point.lat();

            current_lng = point.lng();

            setLatLngFields();

          }

        }

      );

    }

  }

  // Public function to load the map

  this.map_load = function() {

    // All can happen only if there is gmap compatible browser.

    // TODO: Fallback in case the browser is not compatible

    if (GBrowserIsCompatible()) {

      // Save the address fields. This is useful if the page is being edited 

      // to not update blindly the lat/lng fields with GMap geocoding if 

      // blurring an address field

      saveOldAddress();

      var starting_point;

      var zoom_selected = world_zoom;

      var show_marker = true;

      // Create the map and add small controls

      map = new GMap2(document.getElementById(map_div));

      map.addControl(new GSmallMapControl());

      map.addControl(new GMapTypeControl());

      // Instantiate a global geocoder for future use

      geocoder = new GClientGeocoder();

      // If lat and lng fields are not void (the page is being edited) then 

      // update the starting coords, modify the zoom level and tells following 

      // code to show the marker

      if ($(field_lat).val()!="" && $(field_lng).val()!="") {

        readLatLngFields();

        zoom_selected = address_zoom;

        show_marker = true;

      }

      // Set map center, marker coords and show it if this is an editing

      starting_point = new GLatLng(current_lat,current_lng);

      map.setCenter(starting_point, zoom_selected);

      marker = new GMarker(starting_point, {draggable:true});

      if (show_marker) map.addOverlay(marker);

      // Adds a new event listener to geocode the address when an address 

      // field is blurred

      for (var a in address) {

        $(address[a].id).blur(calculateAddress);

      }

      // Adds a new event listener: if the marker has been dragged around...

      GEvent.addListener(marker, "dragend", function() {

        // Update internal variables with current marker coords...

        current_lat = marker.getPoint().lat();

        current_lng = marker.getPoint().lng();

        // ...and set page fields accordingly

        setLatLngFields();

      });

    }

  }

};