var Drag = {
	
	obj : null,
	
	init : function( o, oRoot, minX, maxX, minY, maxY, bar_cls_box, bSwapHorzRef, bSwapVertRef, fXMapper, fYMapper ) {
		
		o.onmousedown	= Drag.start;
		o.hmode			= bSwapHorzRef ? false : true ;
		o.vmode			= bSwapVertRef ? false : true ;
		o.bar_cls_box	= bar_cls_box;
		
		o.root = oRoot && oRoot != null ? oRoot : o ;
		
		if ( o.hmode  && isNaN( parseInt( o.root.style.left   ) ) ) o.root.style.left   = o.root.offsetLeft + "px";
		if ( o.vmode  && isNaN( parseInt( o.root.style.top    ) ) ) o.root.style.top    = o.root.offsetTop + "px";
		if ( !o.hmode && isNaN( parseInt( o.root.style.right  ) ) ) o.root.style.right  = "0px";
		if ( !o.vmode && isNaN( parseInt( o.root.style.bottom ) ) ) o.root.style.bottom = "0px";
		
		o.minX	= typeof minX != 'undefined' ? minX : null;
		o.minY	= typeof minY != 'undefined' ? minY : null;
		o.maxX	= typeof maxX != 'undefined' ? maxX : null;
		o.maxY	= typeof maxY != 'undefined' ? maxY : null;
		
		o.xMapper = fXMapper ? fXMapper : null;
		o.yMapper = fYMapper ? fYMapper : null;
		
		o.root.onDragStart	= new Function(  );
		o.root.onDragEnd	= new Function(  );
		o.root.onDrag		= new Function(  );
	},
	
	start : function( e ) {
		
		var o = Drag.obj = this;
		e = Drag.fixE( e );
		var y = parseInt( o.vmode ? o.root.style.top  : o.root.style.bottom );
		var x = parseInt( o.hmode ? o.root.style.left : o.root.style.right );
		o.root.onDragStart( x, y );
		
		bar_hide( Drag.obj.root.id, o.bar_cls_box );
		
		o.lastMouseX	= e.clientX;
		o.lastMouseY	= e.clientY;
		
		if ( o.hmode ) {
			
			if ( o.minX != null )	{ o.minMouseX	= e.clientX - x + o.minX; 			}
			if ( o.maxX != null )	{ o.maxMouseX	= o.minMouseX + o.maxX - o.minX;	}
		}
		else {
			
			if ( o.minX != null )	{ o.maxMouseX	= -o.minX + e.clientX + x;			}
			if ( o.maxX != null )	{ o.minMouseX	= -o.maxX + e.clientX + x;			}
		}

		if ( o.vmode ) {
			
			if ( o.minY != null )	{ o.minMouseY	= e.clientY - y + o.minY;			}
			if ( o.maxY != null )	{ o.maxMouseY	= o.minMouseY + o.maxY - o.minY;	}
		}
		else {
			
			if ( o.minY != null )	{ o.maxMouseY	= -o.minY + e.clientY + y;			}
			if ( o.maxY != null )	{ o.minMouseY	= -o.maxY + e.clientY + y;			}
		}
		
		document.onmousemove	= Drag.drag;
		document.onmouseup		= Drag.end;
		
		return false;
	},
	
	drag : function( e ) {
		
		e			= Drag.fixE( e );
		var o		= Drag.obj;
		var ey		= e.clientY;
		var ex		= e.clientX;
		var y		= parseInt( o.vmode ? o.root.style.top  : o.root.style.bottom );
		var x		= parseInt( o.hmode ? o.root.style.left : o.root.style.right );
		var nx, ny;
		var info	= Array(  );
		
		if ( o.minX != null ) ex = o.hmode ? Math.max( ex, o.minMouseX ) : Math.min( ex, o.maxMouseX );
		if ( o.maxX != null ) ex = o.hmode ? Math.min( ex, o.maxMouseX ) : Math.max( ex, o.minMouseX );
		if ( o.minY != null ) ey = o.vmode ? Math.max( ey, o.minMouseY ) : Math.min( ey, o.maxMouseY );
		if ( o.maxY != null ) ey = o.vmode ? Math.min( ey, o.maxMouseY ) : Math.max( ey, o.minMouseY );
		
		nx = x + ( ( ex - o.lastMouseX ) * ( o.hmode ? 1 : -1 ) );
		ny = y + ( ( ey - o.lastMouseY ) * ( o.vmode ? 1 : -1 ) );
		
		if ( o.xMapper )		{ nx = o.xMapper( y ); }
		else if ( o.yMapper )	{ ny = o.yMapper( x ); }
		
		Drag.obj.root.style[o.hmode ? "left" : "right"] = nx + "px";
		Drag.obj.root.style[o.vmode ? "top" : "bottom"] = ny + "px";
		Drag.obj.lastMouseX	= ex;
		Drag.obj.lastMouseY	= ey;
		
		info['ex']			= ex;
		info['ey']			= ey;
		info['el']			= o.root.id;
		info['type']			= 'move';
		
		do_act( info );
		
		Drag.obj.root.onDrag( nx, ny );
		return false;
	},
	
	end : function(  ) {
		
	 	bar_show( Drag.obj.root.id, Drag.obj.bar_cls_box );
	 	
		document.onmousemove = null;
		document.onmouseup   = null;
		Drag.obj.root.onDragEnd(	parseInt( Drag.obj.root.style[Drag.obj.hmode ? "left" : "right"] ), 
									parseInt( Drag.obj.root.style[Drag.obj.vmode ? "top" : "bottom"] )
								);
		Drag.obj = null;
	},
	
	fixE : function( e ) {
		
		if ( typeof e == 'undefined'		)	{ e = window.event; }
		if ( typeof e.layerX == 'undefined'	)	{ e.layerX = e.offsetX; }
		if ( typeof e.layerY == 'undefined'	)	{ e.layerY = e.offsetY; }
		
		return e;
	}
};