var GMapCircleArea = function (map) {
  this.active = false;
  this.marker = null;
  this.circle = null;
  this.map = map;
}

GMapCircleArea.prototype = {

  drawArea: function (opt_options)
  {
    var options = opt_options || {};

    this.drawMarker({
      'position': options['position'] || this.map.getCenter()
    });

    this.drawCircle({
      'position': options['position'] || this.map.getCenter(),
      'radius': options['radius'] || 0
    });

    return this;
  },

  /**
   * Add a Google Map marker to the current map
   */
  drawMarker: function(opt_options)
  {
    var options = opt_options || {};

    spCircleArea.gMarker = new google.maps.Marker({
      map: this.map,
      draggable: true,
      position: options['position'] || this.map.getCenter(),
      animation: google.maps.Animation.DROP,
      title: 'Move me!'
    });

    var self = this;
    google.maps.event.addListener(this.marker, 'dragstart', function() {
      self.updateCircleCenter();
    });
    google.maps.event.addListener(spCircleArea.gMarker, 'drag', function() {
      self.updateCircleCenter();
    });
    google.maps.event.addListener(spCircleArea  .gMarker, 'dragend', function() {
      self.updateCircleCenter();
    });

    return this;
  },

  /**
   * Add a Google Map Circle to the current map
   */
  drawCircle: function (opt_options)
  {
    var options = opt_options || {};
    var radius = parseInt(options['radius'] || 0)

    this.circle = new google.maps.Circle({
      map: this.map,
      center: this.marker.getPosition(),
      strokeWeight: 2,
      radius: radius
    });

    return this;
  },

  updateCircleCenter: function ()
  {
    this.circle.setCenter(spCircleArea.gMarker.getPosition());

    return this;
  }

};





var map = new google.maps.Map(document.getElementById('map'), {
            center: new google.maps.LatLng(48.856614, 2.3522219000000177),
            zoom: 8,
            mapTypeId: google.maps.MapTypeId.ROADMAP
          }),
    spCircleArea = new GMapCircleArea(map),
    area = spCircleArea.drawArea({'position:LatLng, 'radius':radius});