var EYES__MODULE_ID__ = {
  MAX_DIST : 14,     // furthest pupil can move from center
  EYE_RADIUS : 30,   // eye image width / 2
  PUPIL_RADIUS : 3,  // pupil image width / 2
  pupils : [],

  init : function() {
    _IG_AddDOMEventHandler(document, "mousemove", EYES__MODULE_ID__.moveEyes);
    EYES__MODULE_ID__.pupils =
      [ _gel("EYES_pupil0__MODULE_ID__"), _gel("EYES_pupil1__MODULE_ID__") ];
  },

  moveEyes : function(e) {
    if (!e) e = window.event;
    var app = EYES__MODULE_ID__;

    for (var i = 0; i < app.pupils.length; i++) {
      var pupil = app.pupils[i];

      // The middle points of the eyes
      var midx = app.getPagePos(pupil.parentNode,true) + app.EYE_RADIUS;
      var midy = app.getPagePos(pupil.parentNode,false) + app.EYE_RADIUS;

      // Page scroll
      var scrollx = 0;
      var scrolly = 0;
      if (typeof(window.pageXOffset) == 'number') {
        scrollx = window.pageXOffset;
        scrolly = window.pageYOffset;
      } else {
        scrollx = document.documentElement.scrollLeft;
        scrolly = document.documentElement.scrollTop;
      }

      // The distX/distY from eye middles to the mouse
      var distX = e.clientX + scrollx - midx;
      var distY = e.clientY + scrolly - midy;

      // The absolute distance from eye middles to the mouse
      var dist = Math.sqrt(Math.pow(distX, 2) + Math.pow(distY, 2));

      if (dist > app.MAX_DIST) {
        // mouse out of eyeball, scale distX/distY to be at eyeball edge
        var scale = app.MAX_DIST / dist;
        distX *= scale; distY *= scale;
      }

      // Place the pupil appropriately
      pupil.style.left = parseInt(distX + app.EYE_RADIUS - app.PUPIL_RADIUS) + "px";
      pupil.style.top = parseInt(distY + app.EYE_RADIUS - app.PUPIL_RADIUS) + "px";
    }
  },

  // get page coords for an element
  getPagePos : function(el, left) {
    var val=0;
    while(el != null) {
      val += el["offset"+(left?"Left":"Top")];
      el = el.offsetParent;
    }
    return val;
  }

};

EYES__MODULE_ID__.init();