/*
  Trouble shooting:  
    Margins thow off the position in IE (use Padding instead)
*/
if(navigator && navigator.vendor && navigator.vendor.indexOf('Apple')==0) SAFARI=true; else SAFARI=false;
function DragObject(element,notTransparent){
  this.debug=false;
  this.container=element;
  if(notTransparent) this.transparent=false;
  else this.transparent=true;
  element.dragObject=this;
  
  this.handleCount=0;
  this.findHandles(this.container);  
  
  this.onDragStart=new Function();
  this.onDrag=new Function();
  this.onDragEnd=new Function();
  
  this.constrain=null;
  
  // if no handles were found THIS is the handle.
  if(this.handleCount==0){
    this.createHandle(this.container);
  }
  
  this.isDragging=false;
  this.threshold=2;
  this.safariAdjust=1;
}

// find all elements within element with "isDragHandle" defined (create handles based on these elements)
function DragObject_findHandles(obj){
  var x=obj.childNodes;
  if(obj.childNodes!=null){
    for(var i=0; i<x.length; i++){
      if(x[i].tagName!=null&&x[i].getAttribute("isDragHandle")){

         this.createHandle(x[i]);
      }
      this.findHandles(x[i]);
    }
  }    
}

// define an element as a drag handle for this object.  
// only start dragging when a handle is clicked.
function DragObject_createHandle(element){
   this.handleCount++;
   var instance=this;
   element.onmousedown=function(evt){instance.onMouseDown(evt);};
}   

function DragObject_onMouseDown(evt) {  
		evt = new Evt(evt);
    if(evt.source.tagName=='SELECT') return true;  // fix for safari select boxes.
		var mouse = new Coordinate(evt.x,evt.y);
    var offset=Geometry.offsetBox(this.container);
    var position;
    if(this.container.style.position=="absolute") position=offset;
    else position=Geometry.positionBox(this.container);    
    
//		this.originalOpacity = this.container.style.opacity;
		this.originalZIndex = this.container.style.zIndex;
        
		this.initialMouseCoordinate = mouse;
		this.dragCoordinate = mouse;

		this.onDragStart(position, offset);
    
    var instance= this;
		document.onmousemove = function(evt){instance.onMouseMove(evt);};
		document.onmouseup = function(evt){instance.onMouseUp(evt);};

		return false;
}

  
  
function DragObject_onMouseMove(evt) {
		evt = new Evt(evt);
		var mouse = new Coordinate(evt.x,evt.y);
    var offset=Geometry.offsetBox(this.container);
    var position;
    if(this.container.style.position=="absolute") position=offset;
    else position=Geometry.positionBox(this.container);    
    var ulPosition=position.upperLeft;


    
		if (!this.isDragging) {
			if (this.threshold > 0) {
				var distance = this.initialMouseCoordinate.distance(mouse);
				if (distance < this.threshold) return true;
			} 
			this.isDragging = true;
			this.container.style["zIndex"] = 999999;
			if(this.transparent) DHTML.setOpacity(this.container,0.5);
      document.body.ondrag = function () { return false; };
      document.body.onselectstart = function () { return false; };     
      if (typeof document.body.style.MozUserSelect!="undefined")  document.body.style.MozUserSelect="none";
    }
   
    var adjustedOffset=offset.upperLeft.plus(mouse.minus(this.dragCoordinate));
    var constrainedOffset=adjustedOffset;
    if(this.constrain) constrainedOffset=adjustedOffset.constrain(this.constrain);


    if(SAFARI){
    var tmpPos=mouse.minus(this.dragCoordinate);
    tmpPos.y=tmpPos.y*(-1);
		ulPosition = ulPosition.plus(tmpPos).plus(constrainedOffset.minus(adjustedOffset)).minus(Geometry.offsetBox(document.body).upperLeft);    
    }else{
		ulPosition = ulPosition.plus(mouse.minus(this.dragCoordinate)).plus(constrainedOffset.minus(adjustedOffset)).minus(Geometry.offsetBox(document.body).upperLeft);    
    }
    
    
    
//   	ulPosition = ulPosition.plus(mouse.minus(this.dragCoordinate)).plus(constrainedOffset.minus(adjustedOffset)).minus(Geometry.offsetBox(document.body).upperLeft);    
		ulPosition.reposition(this.container);
		this.dragCoordinate = mouse;


    
		var offsetBefore = Geometry.upperLeftOffset(this.container);
		this.onDrag(position,offset);
		var offsetAfter = Geometry.upperLeftOffset(this.container);

		if (!offsetBefore.equals(offsetAfter)) {
			var errorDelta = offsetBefore.minus(offsetAfter);
			ulPosition = Geometry.upperLeftOffset(this.container).plus(errorDelta);
			ulPosition.reposition(this.container);
		}
		return false;
}

function DragObject_onMouseUp(evt) {
		evt = new Evt(evt);
		var mouse = new Coordinate(evt.x,evt.y);
    var offset=Geometry.offsetBox(this.container);
    var position;
    if(this.container.style.position=="absolute") position=offset;
    else position=Geometry.positionBox(this.container);    
    var ulPosition=position.upperLeft;

		document.onmousemove = null;
		document.onmouseup   = null;
		this.onDragEnd(position, offset);

		if (this.isDragging) {
			// restoring zIndex before opacity avoids visual flicker in Firefox

			this.container.style["zIndex"] = this.originalZIndex;
			if(this.transparent) DHTML.setOpacity(this.container, 1); // this.originalOpacity);
      document.body.ondrag = null;
      document.body.onselectstart = null;  
      if (typeof document.body.style.MozUserSelect!="undefined")  document.body.style.MozUserSelect="";
		}    
		this.isDragging = false;

		return false;
}

// set the constraining box and reposition
function DragObject_setConstrain(obj){
  this.constrain=Geometry.offsetBox(obj);
  var offset=Geometry.offsetBox(this.container);
  var position;
  if(this.container.style.position=="absolute") position=offset;
  else position=Geometry.positionBox(this.container);    
  var ulPosition=position.upperLeft;

  var adjustedOffset=offset.upperLeft;
  var constrainedOffset=adjustedOffset.constrain(this.constrain);
  ulPosition = ulPosition.plus(constrainedOffset.minus(adjustedOffset));    
	ulPosition.reposition(this.container);
  
}

// show and reposition
DragObject.prototype.setPosition=function(obj){
  this.constrain=null;
  var offset=Geometry.offsetBox(this.container);
  var position=Geometry.offsetBox(obj);
  var ulPosition=position.upperLeft;

  var adjustedOffset=offset.upperLeft;
//  var constrainedOffset=adjustedOffset.constrain(this.constrain);
//  ulPosition = ulPosition.plus(constrainedOffset.minus(adjustedOffset));    
	ulPosition.reposition(this.container);
  
}
DragObject.prototype.setXY=function(x,y){
  this.constrain=null;
  var ulPosition = new Coordinate(x,y);    
	ulPosition.reposition(this.container);
  
}



/*************************  prototypes *******************************/

DragObject.prototype.findHandles=DragObject_findHandles;
DragObject.prototype.createHandle=DragObject_createHandle;
DragObject.prototype.onMouseDown=DragObject_onMouseDown;
DragObject.prototype.onMouseMove=DragObject_onMouseMove;
DragObject.prototype.onMouseUp=DragObject_onMouseUp;
DragObject.prototype.setConstrain=DragObject_setConstrain;