source: sandbox/jabberit_messenger/trophy_expresso/js/dragdrop.js @ 2397

(function()
{
        var _element    = null;
        var _elementA   = null;
        var _elementB   = null;
        var _parent             = null;

        function _configEvent(pObj, pEvent, pHandler)
        {
                try
                {
                        if (typeof pObj == 'object')
                        {
                                if (pEvent.substring(0, 2) == 'on') 
                                        pEvent = pEvent.substring(2, pEvent.length);
                                
                                if (arguments.length == 3)
                                {
                                        if (pObj.addEventListener) 
                                                pObj.addEventListener(pEvent, pHandler, false);
                                        else 
                                                if (pObj.attachEvent) 
                                                        pObj.attachEvent('on' + pEvent, pHandler);
                                }
                                else
                                {
                                        if (arguments.length == 4)
                                        {
                                                if (pObj.removeEventListener && pObj.removeEventListener != 'undefined') 
                                                        pObj.removeEventListener(pEvent, pHandler, false);
                                                else 
                                                        if (pObj.detachEvent) 
                                                                pObj.detachEvent('on' + pEvent, pHandler);
                                        }
                                }
                        }
                }
                catch(e){}
        }

        function _drag(e)
        {
                if (typeof e.preventDefault != 'undefined')
                        e.preventDefault();
                else
                        e.onselectstart = new Function("return false;");

                _element = ( e.target ) ? e.target : e.srcElement;

                if ( _element )
                {
                        _configEvent(_element, 'onmousemove', _mouseMove);
                        _configEvent(top.document, 'onmousemove', _mouseMove);

                        _configEvent(_element, 'onmouseup', _mouseUp);
                        _configEvent(top.document, 'onmouseup', _mouseUp);
                }
        }

        function _elementShadow( pId )
        {
                if( _elementA )
                {
                        var _elShadow                   = document.createElement("div");
                        _elShadow.id                    = _elementA.id + "__Shadow";
                        _elShadow.setAttribute("onselectstart" , "return false");
                        _elShadow.style.width   = _elementA.style.width;
                        _elShadow.style.height  = _elementA.style.height;
                        _elShadow.style.top             = _elementA.style.top;
                        _elShadow.style.left    = _elementA.style.left;
                        _elShadow.style.zIndex  = _elementA.style.zIndex;
                        _elShadow.className             = "x-shadow_Div";
                        
                        return _elShadow;
                }
        }

        function _load()
        {
                if( arguments.length > 0 )
                {
                        var pId = arguments[0];
                        
                        _configEvent(document.getElementById( pId + "__draggable"), 'onmousedown', _mouseDownShadow);
                }
        }

        function _getMouseOffset(e, el)
        {
                var docPos = _getPosition(el);
                var mousePos = _mouseCoords(e);
                return {
                        'x' : mousePos.x - docPos.x,
                        'y' : mousePos.y - docPos.y
                };
        }

        function _getPosition(_pObject)
        {
                var left = 0;
                var top  = 0;

                while ( _pObject.offsetParent )
                {
                        left += _pObject.offsetLeft;
                        top  += _pObject.offsetTop;
                        _pObject = _pObject.offsetParent;
                }

                left += _pObject.offsetLeft;
                top  += _pObject.offsetTop;

                return {
                        'x' : left,
                        'y' : top
                };
        }

        function _mouseCoords(ev)
        {
                var CoordX = "";
                var CoordY = "";

                if ( ev.pageX || ev.pageY )
                        return {
                                'x' : ev.pageX,
                                'y' : ev.pageY
                        };

                CoordX = ev.clientX + document.body.scrollLeft - document.body.clientLeft;
                CoordY = ev.clientY + document.body.scrollTop  - document.body.clientTop;
                
                return {
                        'x' : CoordX,
                        'y' : CoordY
                };
        }

        function _mouseMove(e)
        {
                if ( _element )
                {
                        if ( _element.mouseOffset == null )
                                _element.mouseOffset = _getMouseOffset(e, _element);

                        var mousePos = _mouseCoords(e);

                        var x = mousePos.x - _element.mouseOffset.x;
                        var y = mousePos.y - _element.mouseOffset.y;
                        _element.style.left = (( x < 0 ) ? 0 : x) + 'px';
                        _element.style.top  = (( y < 0 ) ? 0 : y) + 'px';
                }
        }

        function _mouseUp()
        {
                if ( _element )
                {
                        _mouseUpShadow();
                        
                        _configEvent(_element, 'onmousemove', _mouseMove, 'remove');
                        _configEvent(top.document, 'onmousemove', _mouseMove, 'remove');

                        _configEvent(_element, 'onmouseup', _mouseUp, 'remove');
                        _configEvent(top.document, 'onmouseup', _mouseUp, 'remove');

                        _element.mouseOffset = null;
                        _element = null;
                }
        }

        function _mouseDownShadow(e)
        {
                try
                {
                        if( arguments.length > 0 )
                        {
                                var _el = ( e.target ) ? e.target : e.srcElement;
                                var _id = (_el.id.substring(0, _el.id.indexOf("__draggable"))); 
                                
                                _elementA = document.getElementById( _id + "__parent");
                                _elementB = _elementShadow( _id + "__parent");
                                
                                _elementA.style.left = '-1500px';
                                _parent   = _elementA.parentNode;
                                
                                var _B = _parent.appendChild(_elementB);
                                
                                _configEvent( _elementB, 'onmouseup', _mouseUpShadow);
                                _configEvent( _elementB, 'onmousemove', _drag);
                        }
                        
                }catch(e){}
        }

        function _mouseUpShadow()
        {
                try
                {
                        _elementA.style.top             = _elementB.style.top;
                        _elementA.style.left    = _elementB.style.left;
                        
                        var _B = _parent.removeChild(_elementB);

                        _elementA = null;
                        _elementB = null;
                        _element = null;
                }
                catch(e){}
        }
        
        function _drag_drop(){}

        _drag_drop.prototype.set        = _load;
        window._drag_drop = _drag_drop;
        
})();