coordinateFactory = {

  create : function(x, y) {
    return new coordinate(this, x, y);
  },

  topLeftPosition : function(element) {
    if(element == null) return;
    var left = parseInt(element.style["left"]);
    var left = isNaN(left) ? 0 : left;
    var top = parseInt(element.style["top"]);
    var top = isNaN(top) ? 0 : top;

    return this.create(left, top);
  },

  bottomRightPosition : function(element) {
    return this.topLeftPosition(element).plus(this._size(element));
  },

  topLeftOffset : function(element) {
    var offset = this._offset(element);
    var paroff;
    var parent = element.offsetParent;
    while (parent) {
      paroff = this._offset(parent);
      offset = offset.plus(paroff);
      parent = parent.offsetParent;
    }
    return offset;
  },

  bottomRightOffset : function(element) {
    return this.topLeftOffset(element).plus(this.create(element.offsetWidth, element.offsetHeight));
  },

  scrollOffset : function() {
    if (window.pageXOffset) {
      return this.create(window.pageXOffset, window.pageYOffset);
    } else if (document.documentElement) {
      return this.create(document.body.scrollLeft + document.documentElement.scrollLeft, document.body.scrollTop + document.documentElement.scrollTop);
    } else if (document.body.scrollLeft >= 0) {
      return this.create(document.body.scrollLeft, document.body.scrollTop);
    } else {
      return this.create(0, 0);
    }
  },

  clientSize : function() {
    if (window.innerHeight >= 0) {
      return this.create(window.innerWidth, window.innerHeight);
    } else if (document.documentElement) {
      return this.create(document.documentElement.clientWidth, document.documentElement.clientHeight);
    } else if (document.body.clientHeight >= 0) {
      return this.create(document.body.clientWidth, document.body.clientHeight);
    } else {
      return this.create(0, 0);
    }
  },

  mousePosition : function(event) {
    if(!event) event = window.event;
    return this.create(event.clientX, event.clientY);
  },

  mouseOffset : function(event) {
    if(!event) event = window.event;
    if (event.pageX >= 0 || event.pageX < 0) {
      return this.create(event.pageX, event.pageY);
    } else if (event.clientX >= 0 || event.clientX < 0) {
      return this.mousePosition(event).plus(this.scrollOffset());
    }
  },

  _size : function(element) {
    return this.create(element.offsetWidth, element.offsetHeight);
  },

  _offset : function(element) {
    var p = this.create(element.offsetLeft, element.offsetTop);
    return p;
  }
}

function coordinate(factory, x, y) {
  this.factory = factory;
  this.x = isNaN(x) ? null : x;
  this.y = isNaN(y) ? null : y;
}

coordinate.prototype = {
  toString : function() {
    return "(" + this.x + "," + this.y + ")";
  },

  plus : function(that) {
    return this.factory.create(this.x + that.x, this.y + that.y);
  },

  minus : function(that) {
    return this.factory.create(this.x - that.x, this.y - that.y);
  },

  min : function(that) {
    return this.factory.create(Math.min(this.x , that.x), Math.min(this.y , that.y));
  },

  max : function(that) {
    return this.factory.create(Math.max(this.x , that.x), Math.max(this.y , that.y));
  },

  constrainTo : function (one, two) {
    var min = one.min(two);
    var max = one.max(two);

    return this.max(min).min(max);
  },

  distance : function (that) {
    return Math.sqrt(Math.pow(this.x - that.x, 2) + Math.pow(this.y - that.y, 2));
  },

  reposition : function(element) {
    element.style["top"] = this.y + "px";
    element.style["left"] = this.x + "px";
  }
}