Savage.plugin(function (Savage, Element, Paper, glob) {
    var elproto = Element.prototype,
    has = "hasOwnProperty",
    supportsTouch = "createTouch" in glob.doc,
    events = [
        "click", "dblclick", "mousedown", "mousemove", "mouseout",
        "mouseover", "mouseup", "touchstart", "touchmove", "touchend",
        "touchcancel"
    ],
    touchMap = {
        mousedown: "touchstart",
        mousemove: "touchmove",
        mouseup: "touchend"
    },
    getScroll = function (xy) {
        var name = xy == "y" ? "scrollTop" : "scrollLeft";
        return glob.doc.documentElement[name] || glob.doc.body[name];
    },
    preventDefault = function () {
        this.returnValue = false;
    },
    preventTouch = function () {
        return this.originalEvent.preventDefault();
    },
    stopPropagation = function () {
        this.cancelBubble = true;
    },
    stopTouch = function () {
        return this.originalEvent.stopPropagation();
    },
    addEvent = (function () {
        if (glob.doc.addEventListener) {
            return function (obj, type, fn, element) {
                var realName = supportsTouch && touchMap[type] ? touchMap[type] : type,
                    f = function (e) {
                        var scrollY = getScroll("y"),
                            scrollX = getScroll("x"),
                            x = e.clientX + scrollX,
                            y = e.clientY + scrollY;
                    if (supportsTouch && touchMap[has](type)) {
                        for (var i = 0, ii = e.targetTouches && e.targetTouches.length; i < ii; i++) {
                            if (e.targetTouches[i].target == obj) {
                                var olde = e;
                                e = e.targetTouches[i];
                                e.originalEvent = olde;
                                e.preventDefault = preventTouch;
                                e.stopPropagation = stopTouch;
                                break;
                            }
                        }
                    }
                    return fn.call(element, e, x, y);
                };
                obj.addEventListener(realName, f, false);
                return function () {
                    obj.removeEventListener(realName, f, false);
                    return true;
                };
            };
        } else if (glob.doc.attachEvent) {
            return function (obj, type, fn, element) {
                var f = function (e) {
                    e = e || glob.win.event;
                    var scrollY = getScroll("y"),
                        scrollX = getScroll("x"),
                        x = e.clientX + scrollX,
                        y = e.clientY + scrollY;
                    e.preventDefault = e.preventDefault || preventDefault;
                    e.stopPropagation = e.stopPropagation || stopPropagation;
                    return fn.call(element, e, x, y);
                };
                obj.attachEvent("on" + type, f);
                var detacher = function () {
                    obj.detachEvent("on" + type, f);
                    return true;
                };
                return detacher;
            };
        }
    })(),
    drag = [],
    dragMove = function (e) {
        var x = e.clientX,
            y = e.clientY,
            scrollY = getScroll("y"),
            scrollX = getScroll("x"),
            dragi,
            j = drag.length;
        while (j--) {
            dragi = drag[j];
            if (supportsTouch) {
                var i = e.touches.length,
                    touch;
                while (i--) {
                    touch = e.touches[i];
                    if (touch.identifier == dragi.el._drag.id) {
                        x = touch.clientX;
                        y = touch.clientY;
                        (e.originalEvent ? e.originalEvent : e).preventDefault();
                        break;
                    }
                }
            } else {
                e.preventDefault();
            }
            var node = dragi.el.node,
                o,
                next = node.nextSibling,
                parent = node.parentNode,
                display = node.style.display;
            // glob.win.opera && parent.removeChild(node);
            // node.style.display = "none";
            // o = dragi.el.paper.getElementByPoint(x, y);
            // node.style.display = display;
            // glob.win.opera && (next ? parent.insertBefore(node, next) : parent.appendChild(node));
            // o && eve("savage.drag.over." + dragi.el.id, dragi.el, o);
            x += scrollX;
            y += scrollY;
            eve("savage.drag.move." + dragi.el.id, dragi.move_scope || dragi.el, x - dragi.el._drag.x, y - dragi.el._drag.y, x, y, e);
        }
    },
    dragUp = function (e) {
        Savage.unmousemove(dragMove).unmouseup(dragUp);
        var i = drag.length,
            dragi;
        while (i--) {
            dragi = drag[i];
            dragi.el._drag = {};
            eve("savage.drag.end." + dragi.el.id, dragi.end_scope || dragi.start_scope || dragi.move_scope || dragi.el, e);
        }
        drag = [];
    };
    /*\
     * Element.click
     [ method ]
     **
     * Adds event handler for click for the element.
     > Parameters
     - handler (function) handler for the event
     = (object) @Element
    \*/
    /*\
     * Element.unclick
     [ method ]
     **
     * Removes event handler for click for the element.
     > Parameters
     - handler (function) handler for the event
     = (object) @Element
    \*/
    
    /*\
     * Element.dblclick
     [ method ]
     **
     * Adds event handler for double click for the element.
     > Parameters
     - handler (function) handler for the event
     = (object) @Element
    \*/
    /*\
     * Element.undblclick
     [ method ]
     **
     * Removes event handler for double click for the element.
     > Parameters
     - handler (function) handler for the event
     = (object) @Element
    \*/
    
    /*\
     * Element.mousedown
     [ method ]
     **
     * Adds event handler for mousedown for the element.
     > Parameters
     - handler (function) handler for the event
     = (object) @Element
    \*/
    /*\
     * Element.unmousedown
     [ method ]
     **
     * Removes event handler for mousedown for the element.
     > Parameters
     - handler (function) handler for the event
     = (object) @Element
    \*/
    
    /*\
     * Element.mousemove
     [ method ]
     **
     * Adds event handler for mousemove for the element.
     > Parameters
     - handler (function) handler for the event
     = (object) @Element
    \*/
    /*\
     * Element.unmousemove
     [ method ]
     **
     * Removes event handler for mousemove for the element.
     > Parameters
     - handler (function) handler for the event
     = (object) @Element
    \*/
    
    /*\
     * Element.mouseout
     [ method ]
     **
     * Adds event handler for mouseout for the element.
     > Parameters
     - handler (function) handler for the event
     = (object) @Element
    \*/
    /*\
     * Element.unmouseout
     [ method ]
     **
     * Removes event handler for mouseout for the element.
     > Parameters
     - handler (function) handler for the event
     = (object) @Element
    \*/
    
    /*\
     * Element.mouseover
     [ method ]
     **
     * Adds event handler for mouseover for the element.
     > Parameters
     - handler (function) handler for the event
     = (object) @Element
    \*/
    /*\
     * Element.unmouseover
     [ method ]
     **
     * Removes event handler for mouseover for the element.
     > Parameters
     - handler (function) handler for the event
     = (object) @Element
    \*/
    
    /*\
     * Element.mouseup
     [ method ]
     **
     * Adds event handler for mouseup for the element.
     > Parameters
     - handler (function) handler for the event
     = (object) @Element
    \*/
    /*\
     * Element.unmouseup
     [ method ]
     **
     * Removes event handler for mouseup for the element.
     > Parameters
     - handler (function) handler for the event
     = (object) @Element
    \*/
    
    /*\
     * Element.touchstart
     [ method ]
     **
     * Adds event handler for touchstart for the element.
     > Parameters
     - handler (function) handler for the event
     = (object) @Element
    \*/
    /*\
     * Element.untouchstart
     [ method ]
     **
     * Removes event handler for touchstart for the element.
     > Parameters
     - handler (function) handler for the event
     = (object) @Element
    \*/
    
    /*\
     * Element.touchmove
     [ method ]
     **
     * Adds event handler for touchmove for the element.
     > Parameters
     - handler (function) handler for the event
     = (object) @Element
    \*/
    /*\
     * Element.untouchmove
     [ method ]
     **
     * Removes event handler for touchmove for the element.
     > Parameters
     - handler (function) handler for the event
     = (object) @Element
    \*/
    
    /*\
     * Element.touchend
     [ method ]
     **
     * Adds event handler for touchend for the element.
     > Parameters
     - handler (function) handler for the event
     = (object) @Element
    \*/
    /*\
     * Element.untouchend
     [ method ]
     **
     * Removes event handler for touchend for the element.
     > Parameters
     - handler (function) handler for the event
     = (object) @Element
    \*/
    
    /*\
     * Element.touchcancel
     [ method ]
     **
     * Adds event handler for touchcancel for the element.
     > Parameters
     - handler (function) handler for the event
     = (object) @Element
    \*/
    /*\
     * Element.untouchcancel
     [ method ]
     **
     * Removes event handler for touchcancel for the element.
     > Parameters
     - handler (function) handler for the event
     = (object) @Element
    \*/
    for (var i = events.length; i--;) {
        (function (eventName) {
            Savage[eventName] = elproto[eventName] = function (fn, scope) {
                if (Savage.is(fn, "function")) {
                    this.events = this.events || [];
                    this.events.push({
                        name: eventName,
                        f: fn,
                        unbind: addEvent(this.shape || this.node || glob.doc, eventName, fn, scope || this)
                    });
                }
                return this;
            };
            Savage["un" + eventName] = elproto["un" + eventName] = function (fn) {
                var events = this.events || [],
                    l = events.length;
                while (l--) if (events[l].name == eventName && events[l].f == fn) {
                    events[l].unbind();
                    events.splice(l, 1);
                    !events.length && delete this.events;
                    return this;
                }
                return this;
            };
        })(events[i]);
    }
    
    /*\
     * Element.data
     [ method ]
     **
     * Adds or retrieves given value asociated with given key.
     ** 
     * See also @Element.removeData
     > Parameters
     - key (string) key to store data
     - value (any) #optional value to store
     = (object) @Element
     * or, if value is not specified:
     = (any) value
     > Usage
     | for (var i = 0, i < 5, i++) {
     |     paper.circle(10 + 15 * i, 10, 10)
     |          .attr({fill: "#000"})
     |          .data("i", i)
     |          .click(function () {
     |             alert(this.data("i"));
     |          });
     | }
    \*/
    elproto.data = function (key, value) {
        var data = eldata[this.id] = eldata[this.id] || {};
        if (arguments.length == 1) {
            if (Savage.is(key, "object")) {
                for (var i in key) if (key[has](i)) {
                    this.data(i, key[i]);
                }
                return this;
            }
            eve("savage.data.get." + this.id, this, data[key], key);
            return data[key];
        }
        data[key] = value;
        eve("savage.data.set." + this.id, this, value, key);
        return this;
    };
    /*\
     * Element.removeData
     [ method ]
     **
     * Removes value associated with an element by given key.
     * If key is not provided, removes all the data of the element.
     > Parameters
     - key (string) #optional key
     = (object) @Element
    \*/
    elproto.removeData = function (key) {
        if (key == null) {
            eldata[this.id] = {};
        } else {
            eldata[this.id] && delete eldata[this.id][key];
        }
        return this;
    };
    /*\
     * Element.hover
     [ method ]
     **
     * Adds event handlers for hover for the element.
     > Parameters
     - f_in (function) handler for hover in
     - f_out (function) handler for hover out
     - icontext (object) #optional context for hover in handler
     - ocontext (object) #optional context for hover out handler
     = (object) @Element
    \*/
    elproto.hover = function (f_in, f_out, scope_in, scope_out) {
        return this.mouseover(f_in, scope_in).mouseout(f_out, scope_out || scope_in);
    };
    /*\
     * Element.unhover
     [ method ]
     **
     * Removes event handlers for hover for the element.
     > Parameters
     - f_in (function) handler for hover in
     - f_out (function) handler for hover out
     = (object) @Element
    \*/
    elproto.unhover = function (f_in, f_out) {
        return this.unmouseover(f_in).unmouseout(f_out);
    };
    var draggable = [];
    /*\
     * Element.drag
     [ method ]
     **
     * Adds event handlers for drag of the element.
     > Parameters
     - onmove (function) handler for moving
     - onstart (function) handler for drag start
     - onend (function) handler for drag end
     - mcontext (object) #optional context for moving handler
     - scontext (object) #optional context for drag start handler
     - econtext (object) #optional context for drag end handler
     * Additionaly following `drag` events will be triggered: `drag.start.<id>` on start, 
     * `drag.end.<id>` on end and `drag.move.<id>` on every move. When element will be dragged over another element 
     * `drag.over.<id>` will be fired as well.
     *
     * Start event and start handler will be called in specified context or in context of the element with following parameters:
     o x (number) x position of the mouse
     o y (number) y position of the mouse
     o event (object) DOM event object
     * Move event and move handler will be called in specified context or in context of the element with following parameters:
     o dx (number) shift by x from the start point
     o dy (number) shift by y from the start point
     o x (number) x position of the mouse
     o y (number) y position of the mouse
     o event (object) DOM event object
     * End event and end handler will be called in specified context or in context of the element with following parameters:
     o event (object) DOM event object
     = (object) @Element
    \*/
    elproto.drag = function (onmove, onstart, onend, move_scope, start_scope, end_scope) {
        if (!arguments.length) {
            var origTransform;
            return this.drag(function (dx, dy) {
                this.attr({
                    transform: origTransform + (origTransform ? "T" : "t") + [dx, dy]
                });
            }, function () {
                origTransform = this.transform().local;
            });
        }
        function start(e) {
            (e.originalEvent || e).preventDefault();
            var scrollY = getScroll("y"),
                scrollX = getScroll("x");
            this._drag.x = e.clientX + scrollX;
            this._drag.y = e.clientY + scrollY;
            this._drag.id = e.identifier;
            !drag.length && Savage.mousemove(dragMove).mouseup(dragUp);
            drag.push({el: this, move_scope: move_scope, start_scope: start_scope, end_scope: end_scope});
            onstart && eve.on("savage.drag.start." + this.id, onstart);
            onmove && eve.on("savage.drag.move." + this.id, onmove);
            onend && eve.on("savage.drag.end." + this.id, onend);
            eve("savage.drag.start." + this.id, start_scope || move_scope || this, e.clientX + scrollX, e.clientY + scrollY, e);
        }
        this._drag = {};
        draggable.push({el: this, start: start});
        this.mousedown(start);
        return this;
    };
    /*\
     * Element.onDragOver
     [ method ]
     **
     * Shortcut for assigning event handler for `drag.over.<id>` event, where id is id of the element (see @Element.id).
     > Parameters
     - f (function) handler for event, first argument would be the element you are dragging over
    \*/
    elproto.onDragOver = function (f) {
        f ? eve.on("savage.drag.over." + this.id, f) : eve.unbind("savage.drag.over." + this.id);
    };
    /*\
     * Element.undrag
     [ method ]
     **
     * Removes all drag event handlers from given element.
    \*/
    elproto.undrag = function () {
        var i = draggable.length;
        while (i--) if (draggable[i].el == this) {
            this.unmousedown(draggable[i].start);
            draggable.splice(i, 1);
            eve.unbind("savage.drag.*." + this.id);
        }
        !draggable.length && Savage.unmousemove(dragMove).unmouseup(dragUp);
    };
});