(function() {
    var blacklist = {
        node: 1,
        duration: 1,
        easing: 1,
        onFinish: 1,
        yoyo: 1
    },

    PAUSED = 1,
    PLAYING = 2,
    REVERSING = 3,

    idCounter = 0;

    /**
     * Tween constructor.  Tweens enable you to animate a node between the current state and a new state.
     *  You can play, pause, reverse, seek, reset, and finish tweens.  By default, tweens are animated using
     *  a linear easing.  For more tweening options, check out {@link Kinetic.Easings}
     * @constructor
     * @memberof Kinetic
     * @example
     * // instantiate new tween which fully rotates a node in 1 second
     * var tween = new Kinetic.Tween({<br>
     *   node: node,<br>
     *   rotationDeg: 360,<br>
     *   duration: 1,<br>
     *   easing: Kinetic.Easings.EaseInOut<br>
     * });<br><br>
     *
     * // play tween<br>
     * tween.play();<br><br>
     *
     * // pause tween<br>
     * tween.pause();
     */
    Kinetic.Tween = function(config) {
        var that = this,
            node = config.node,
            nodeId = node._id,
            duration = config.duration || 1,
            easing = config.easing || Kinetic.Easings.Linear,
            yoyo = !!config.yoyo,
            key, tween, start, tweenId;

        this.node = node;
        this._id = idCounter++;

        this.anim = new Kinetic.Animation(function() {
            that.tween.onEnterFrame();
        }, node.getLayer() || node.getLayers());

        this.tween = new Tween(key, function(i) {
            that._tweenFunc(i);
        }, easing, 0, 1, duration * 1000, yoyo);

        this._addListeners();

        // init attrs map
        if (!Kinetic.Tween.attrs[nodeId]) {
            Kinetic.Tween.attrs[nodeId] = {};
        }
        if (!Kinetic.Tween.attrs[nodeId][this._id]) {
            Kinetic.Tween.attrs[nodeId][this._id] = {};
        }
        // init tweens map
        if (!Kinetic.Tween.tweens[nodeId]) {
            Kinetic.Tween.tweens[nodeId] = {};
        }

        for (key in config) {
            if (blacklist[key] === undefined) {
                this._addAttr(key, config[key]);
            }
        }

        this.reset();

        // callbacks
        this.onFinish = config.onFinish;
        this.onReset = config.onReset;
    };

    // start/diff object = attrs.nodeId.tweenId.attr
    Kinetic.Tween.attrs = {};
    // tweenId = tweens.nodeId.attr
    Kinetic.Tween.tweens = {};

    Kinetic.Tween.prototype = {
        _addAttr: function(key, end) {
            var node = this.node,
                nodeId = node._id,
                start, diff, tweenId, n, len, startVal, endVal;

            // remove conflict from tween map if it exists
            tweenId = Kinetic.Tween.tweens[nodeId][key];

            if (tweenId) {
                delete Kinetic.Tween.attrs[nodeId][tweenId][key];
            }

            // add to tween map
            start = node.getAttr(key);

            if (Kinetic.Util._isArray(end)) {
                end = Kinetic.Util._getPoints(end);
                diff = [];
                len = end.length;
                for (n=0; n<len; n++) {
                    startVal = start[n];
                    endVal = end[n];
                    diff.push({
                        x: endVal.x - startVal.x,
                        y: endVal.y - startVal.y
                    });
                }

            }
            else {
                diff = end - start;
            }

            Kinetic.Tween.attrs[nodeId][this._id][key] = {
                start: start,
                diff: diff
            };
            Kinetic.Tween.tweens[nodeId][key] = this._id;
        },
        _tweenFunc: function(i) {
            var node = this.node,
                attrs = Kinetic.Tween.attrs[node._id][this._id],
                key, attr, start, diff, newVal, n, len, startVal, diffVal;

            for (key in attrs) {
                attr = attrs[key];
                start = attr.start;
                diff = attr.diff;

                if (Kinetic.Util._isArray(start)) {
                    newVal = [];
                    len = start.length;
                    for (n=0; n<len; n++) {
                        startVal = start[n];
                        diffVal = diff[n];
                        newVal.push({
                            x: startVal.x + (diffVal.x * i),
                            y: startVal.y + (diffVal.y * i)
                        });
                    }
                }
                else {
                    newVal = start + (diff * i);
                }

                node.setAttr(key, newVal);
            }
        },
        _addListeners: function() {
            var that = this;

            // start listeners
            this.tween.onPlay = function() {
                that.anim.start();
            };
            this.tween.onReverse = function() {
                that.anim.start();
            };

            // stop listeners
            this.tween.onPause = function() {
                that.anim.stop();
            };
            this.tween.onFinish = function() {
                if (that.onFinish) {
                    that.onFinish();
                }
            };
            this.tween.onReset = function() {
                if (that.onReset) {
                    that.onReset();
                }
            };
        },
        /**
         * play
         * @method
         * @memberof Kinetic.Tween.prototype
         */
        play: function() {
            this.tween.play();
            return this;
        },
        /**
         * reverse
         * @method
         * @memberof Kinetic.Tween.prototype
         */
        reverse: function() {
            this.tween.reverse();
            return this;
        },
        /**
         * reset
         * @method
         * @memberof Kinetic.Tween.prototype
         */
        reset: function() {
            var node = this.node;
            this.tween.reset();
            (node.getLayer() || node.getLayers()).draw();
            return this;
        },
        /**
         * seek
         * @method
         * @memberof Kinetic.Tween.prototype
         * @param {Integer} t time in seconds between 0 and the duration
         */
        seek: function(t) {
            var node = this.node;
            this.tween.seek(t * 1000);
            (node.getLayer() || node.getLayers()).draw();
            return this;
        },
        /**
         * pause
         * @method
         * @memberof Kinetic.Tween.prototype
         */
        pause: function() {
            this.tween.pause();
            return this;
        },
        /**
         * finish
         * @method
         * @memberof Kinetic.Tween.prototype
         */
        finish: function() {
            var node = this.node;
            this.tween.finish();
            (node.getLayer() || node.getLayers()).draw();
            return this;
        },
        /**
         * destroy
         * @method
         * @memberof Kinetic.Tween.prototype
         */
        destroy: function() {
            var nodeId = this.node._id,
                thisId = this._id,
                attrs = Kinetic.Tween.tweens[nodeId],
                key;

            this.pause();

            for (key in attrs) {
                delete Kinetic.Tween.tweens[nodeId][key];
            }

            delete Kinetic.Tween.attrs[nodeId][thisId];
        }
    };

    var Tween = function(prop, propFunc, func, begin, finish, duration, yoyo) {
        this.prop = prop;
        this.propFunc = propFunc;
        this.begin = begin;
        this._pos = begin;
        this.duration = duration;
        this._change = 0;
        this.prevPos = 0;
        this.yoyo = yoyo;
        this._time = 0;
        this._position = 0;
        this._startTime = 0;
        this._finish = 0;
        this.func = func;
        this._change = finish - this.begin;
        this.pause();
    };
    /*
     * Tween methods
     */
    Tween.prototype = {
        fire: function(str) {
            var handler = this[str];
            if (handler) {
                handler();
            }
        },
        setTime: function(t) {
            if(t > this.duration) {
                if(this.yoyo) {
                    this._time = this.duration;
                    this.reverse();
                }
                else {
                    this.finish();
                }
            }
            else if(t < 0) {
                if(this.yoyo) {
                    this._time = 0;
                    this.play();
                }
                else {
                    this.reset();
                }
            }
            else {
                this._time = t;
                this.update();
            }
        },
        getTime: function() {
            return this._time;
        },
        setPosition: function(p) {
            this.prevPos = this._pos;
            this.propFunc(p);
            this._pos = p;
        },
        getPosition: function(t) {
            if(t === undefined) {
                t = this._time;
            }
            return this.func(t, this.begin, this._change, this.duration);
        },
        play: function() {
            this.state = PLAYING;
            this._startTime = this.getTimer() - this._time;
            this.onEnterFrame();
            this.fire('onPlay');
        },
        reverse: function() {
            this.state = REVERSING;
            this._time = this.duration - this._time;
            this._startTime = this.getTimer() - this._time;
            this.onEnterFrame();
            this.fire('onReverse');
        },
        seek: function(t) {
            this.pause();
            this._time = t;
            this.update();
            this.fire('onSeek');
        },
        reset: function() {
            this.pause();
            this._time = 0;
            this.update();
            this.fire('onReset');
        },
        finish: function() {
            this.pause();
            this._time = this.duration;
            this.update();
            this.fire('onFinish');
        },
        update: function() {
            this.setPosition(this.getPosition(this._time));
        },
        onEnterFrame: function() {
            var t = this.getTimer() - this._startTime;
            if(this.state === PLAYING) {
                this.setTime(t);
            }
            else if (this.state === REVERSING) {
                this.setTime(this.duration - t);
            }
        },
        pause: function() {
            this.state = PAUSED;
            this.fire('onPause');
        },
        getTimer: function() {
            return new Date().getTime();
        }
    };

    /*
    * These eases were ported from an Adobe Flash tweening library to JavaScript
    * by Xaric
    */

    /**
     * @namespace Easings
     * @memberof Kinetic
     */
    Kinetic.Easings = {
        /**
        * back ease in
        * @function
        * @memberof Kinetic.Easings
        */
        'BackEaseIn': function(t, b, c, d, a, p) {
            var s = 1.70158;
            return c * (t /= d) * t * ((s + 1) * t - s) + b;
        },
        /**
        * back ease out
        * @function
        * @memberof Kinetic.Easings
        */
        'BackEaseOut': function(t, b, c, d, a, p) {
            var s = 1.70158;
            return c * (( t = t / d - 1) * t * ((s + 1) * t + s) + 1) + b;
        },
        /**
        * back ease in out
        * @function
        * @memberof Kinetic.Easings
        */
        'BackEaseInOut': function(t, b, c, d, a, p) {
            var s = 1.70158;
            if((t /= d / 2) < 1) {
                return c / 2 * (t * t * (((s *= (1.525)) + 1) * t - s)) + b;
            }
            return c / 2 * ((t -= 2) * t * (((s *= (1.525)) + 1) * t + s) + 2) + b;
        },
        /**
        * elastic ease in
        * @function
        * @memberof Kinetic.Easings
        */
        'ElasticEaseIn': function(t, b, c, d, a, p) {
            // added s = 0
            var s = 0;
            if(t === 0) {
                return b;
            }
            if((t /= d) == 1) {
                return b + c;
            }
            if(!p) {
                p = d * 0.3;
            }
            if(!a || a < Math.abs(c)) {
                a = c;
                s = p / 4;
            }
            else {
                s = p / (2 * Math.PI) * Math.asin(c / a);
            }
            return -(a * Math.pow(2, 10 * (t -= 1)) * Math.sin((t * d - s) * (2 * Math.PI) / p)) + b;
        },
        /**
        * elastic ease out
        * @function
        * @memberof Kinetic.Easings
        */
        'ElasticEaseOut': function(t, b, c, d, a, p) {
            // added s = 0
            var s = 0;
            if(t === 0) {
                return b;
            }
            if((t /= d) == 1) {
                return b + c;
            }
            if(!p) {
                p = d * 0.3;
            }
            if(!a || a < Math.abs(c)) {
                a = c;
                s = p / 4;
            }
            else {
                s = p / (2 * Math.PI) * Math.asin(c / a);
            }
            return (a * Math.pow(2, -10 * t) * Math.sin((t * d - s) * (2 * Math.PI) / p) + c + b);
        },
        /**
        * elastic ease in out
        * @function
        * @memberof Kinetic.Easings
        */
        'ElasticEaseInOut': function(t, b, c, d, a, p) {
            // added s = 0
            var s = 0;
            if(t === 0) {
                return b;
            }
            if((t /= d / 2) == 2) {
                return b + c;
            }
            if(!p) {
                p = d * (0.3 * 1.5);
            }
            if(!a || a < Math.abs(c)) {
                a = c;
                s = p / 4;
            }
            else {
                s = p / (2 * Math.PI) * Math.asin(c / a);
            }
            if(t < 1) {
                return -0.5 * (a * Math.pow(2, 10 * (t -= 1)) * Math.sin((t * d - s) * (2 * Math.PI) / p)) + b;
            }
            return a * Math.pow(2, -10 * (t -= 1)) * Math.sin((t * d - s) * (2 * Math.PI) / p) * 0.5 + c + b;
        },
        /**
        * bounce ease out
        * @function
        * @memberof Kinetic.Easings
        */
        'BounceEaseOut': function(t, b, c, d) {
            if((t /= d) < (1 / 2.75)) {
                return c * (7.5625 * t * t) + b;
            }
            else if(t < (2 / 2.75)) {
                return c * (7.5625 * (t -= (1.5 / 2.75)) * t + 0.75) + b;
            }
            else if(t < (2.5 / 2.75)) {
                return c * (7.5625 * (t -= (2.25 / 2.75)) * t + 0.9375) + b;
            }
            else {
                return c * (7.5625 * (t -= (2.625 / 2.75)) * t + 0.984375) + b;
            }
        },
        /**
        * bounce ease in
        * @function
        * @memberof Kinetic.Easings
        */
        'BounceEaseIn': function(t, b, c, d) {
            return c - Kinetic.Easings.BounceEaseOut(d - t, 0, c, d) + b;
        },
        /**
        * bounce ease in out
        * @function
        * @memberof Kinetic.Easings
        */
        'BounceEaseInOut': function(t, b, c, d) {
            if(t < d / 2) {
                return Kinetic.Easings.BounceEaseIn(t * 2, 0, c, d) * 0.5 + b;
            }
            else {
                return Kinetic.Easings.BounceEaseOut(t * 2 - d, 0, c, d) * 0.5 + c * 0.5 + b;
            }
        },
        /**
        * ease in
        * @function
        * @memberof Kinetic.Easings
        */
        'EaseIn': function(t, b, c, d) {
            return c * (t /= d) * t + b;
        },
        /**
        * ease out
        * @function
        * @memberof Kinetic.Easings
        */
        'EaseOut': function(t, b, c, d) {
            return -c * (t /= d) * (t - 2) + b;
        },
        /**
        * ease in out
        * @function
        * @memberof Kinetic.Easings
        */
        'EaseInOut': function(t, b, c, d) {
            if((t /= d / 2) < 1) {
                return c / 2 * t * t + b;
            }
            return -c / 2 * ((--t) * (t - 2) - 1) + b;
        },
        /**
        * strong ease in
        * @function
        * @memberof Kinetic.Easings
        */
        'StrongEaseIn': function(t, b, c, d) {
            return c * (t /= d) * t * t * t * t + b;
        },
        /**
        * strong ease out
        * @function
        * @memberof Kinetic.Easings
        */
        'StrongEaseOut': function(t, b, c, d) {
            return c * (( t = t / d - 1) * t * t * t * t + 1) + b;
        },
        /**
        * strong ease in out
        * @function
        * @memberof Kinetic.Easings
        */
        'StrongEaseInOut': function(t, b, c, d) {
            if((t /= d / 2) < 1) {
                return c / 2 * t * t * t * t * t + b;
            }
            return c / 2 * ((t -= 2) * t * t * t * t + 2) + b;
        },
        /**
        * linear
        * @function
        * @memberof Kinetic.Easings
        */
        'Linear': function(t, b, c, d) {
            return c * t / d + b;
        }
    };
})();