/**
 * A wrapper around HTML5 Geolocation with helper methods.
 *
 * @constructor
 */
function Geo() {
  "use strict";

  /**
   * @type {Geolocation}
   */
  var geo = navigator.geolocation;

  this.getGeo = function () {
    return geo;
  };

  /**
   *
   * @param {MessageElement} area
   */
  this.showLocation = function (area) {
    var that = this;
    geo.getCurrentPosition(
      function (position) {
        area.set(that.getPositionMessage(position));
      },
      function (error) {
        area.set(that.getPositionError(error));
      }
    );
  };

  /**
   * Build a string representation of a Geolocation PositionError.
   *
   * @param {PositionError} error
   *
   * @returns {*}
   */
  this.getPositionError = function(error) {
    "use strict";
    var reason;
    switch (error.code) {
      case error.POSITION_UNAVAILABLE:
        reason = "Position unavailable";
        break;
      case error.PERMISSION_DENIED:
        reason = "Permission denied";
        break;
      case error.TIMEOUT:
        reason = "Timeout"
        break;
      default:
        reason = "Unknown position error (" + error.code + ")";
        break;
    }

    var ret = reason + ": " + error.message;
    return ret;
  };

  /**
   * Build a HTML-formatted representation of a position information.
   *
   * @param {Position} position
   * @returns {string}
   */
  this.getPositionMessage = function (position) {
    /**
     * @type {Coordinates}
     */
    var coords = position.coords;

    var date = new Date(position.timestamp);

    var message = "<p>Position: </p>\n" +
      "<ul>\n" +
      "  <li>Timestamp: " + position.timestamp + " = " + date.toLocaleString() + "</li>\n" +
      "  <li>Accuracy: " + coords.accuracy + " meters</li>\n" +
      "  <li>Latitude: " + coords.latitude + "</li>" +
      "  <li>Longitude: " + coords.longitude + "</li>" +
      "  <li>Altitude: " + (coords.altitude ? coords.altitude : "unknown") + "</li>" +
      "  <li>Altitude Accuracy: " + (coords.altitudeAccuracy ? coords.altitudeAccuracy : 0) + "</li>" +
      "  <li>Heading: " + (coords.heading ? coords.heading : "unknown") + "</li>\n" +
      "  <li>Speed: " + (coords.speed ? coords.speed : "unknown") + "</li>\n" +
      "  </ul>\n";

    return message;
  };

  this.init = function () {
    geo = navigator.geolocation || false;
  };

  this.init();
}