/*
 * operaGeolocationWrapper.js
 * ---------------------------------
 * Wrapper for Opera Geolocation functionality using Nokia WRT location service object
 *
 * Currently, only the 'one shot' location functionality is available.
 *
 * Licensed under the BSD License.
 * Originally developed by Metropolia Media Works / Andrew Wharton
 * Supported by Forum Nokia
 * version: 1.0
 * --------------
 */

/*
 * Global variables
 */

//used to store the name of the callback function so it is globally accessible
var _callbackName;

navigator.geolocation = new Object();
navigator.geolocation.getCurrentPosition = getCurrentPosition;

/*
 * getCurrentPosition
 * ------------------
 * Calls the WRT GetLocation asynchronous function and returns immediately
 */

function getCurrentPosition(callback)
{
    // save the callback to a global variable for later use
    _callbackName = callback;
    // get a service object
    var so = device.getServiceObject("Service.Location", "ILocation");
    // create a criteria object
    var criteria = new Object();
    criteria.LocationInformationClass = "GenericLocationInfo";
    // call the GetLocation method
    // passes criteria object and callback method as arguments
    result = so.ILocation.GetLocation(criteria, _callback);
    // return result so that code can continue
    return result;

}

/*
 * _callback
 * ---------
 * Intermediate callback funtion to modify the position object before passing it to the real callback function
 * -takes the Nokia ReturnValue object, extracts the required information
 * -creates a new position object in the W3C form
 * -invokes the user defined callback using the modified object as argument
 */

var _callback = function(transId, eventCode, result)
{
    // store the nokia position object info into a temporary location
    var latitude = result.ReturnValue.Latitude;
    var longitude = result.ReturnValue.Longitude;
    var altitude = result.ReturnValue.Altitude;
    var altitudeAccuracy = null; // unable to obtain, therefore must be null as per W3C geolocation spec
    var heading = result.ReturnValue.TrueCourse;
    var speed = result.ReturnValue.HorizontalSpeed;
    
    // Create the new position object
    var Position = new Object();
    Position.coords = new Object();
    
    // add attributes to new position object
    Position.coords.latitude = latitude;
    Position.coords.longitude = longitude;
    Position.coords.altitude = altitude;
    Position.coords.altitudeAccuracy = altitudeAccuracy;
    Position.coords.heading = heading;
    Position.coords.speed = speed;
    
    // invoke the user defined callback function with the Position object as argument
    _callbackName(Position);
}