/**
* Provides the base Transition class, for animating numeric properties.
*
* @module transition
* @submodule transition-timer
*/
 
 
var Transition = Y.Transition;
 
Y.mix(Transition.prototype, {
    _start: function() {
        if (Transition.useNative) {
            this._runNative();
        } else {
            this._runTimer();
        }
    },
 
    _runTimer: function() {
        var anim = this;
        anim._initAttrs();
 
        Transition._running[Y.stamp(anim)] = anim;
        anim._startTime = new Date();
        Transition._startTimer();
    },
 
    _endTimer: function() {
        var anim = this;
        delete Transition._running[Y.stamp(anim)];
        anim._startTime = null;
    },
 
    _runFrame: function() {
        var t = new Date() - this._startTime;
        this._runAttrs(t);
    },
 
    _runAttrs: function(time) {
        var anim = this,
            node = anim._node,
            config = anim._config,
            uid = Y.stamp(node),
            attrs = Transition._nodeAttrs[uid],
            customAttr = Transition.behaviors,
            done = false,
            allDone = false,
            data,
            name,
            attribute,
            setter,
            elapsed,
            delay,
            d,
            t,
            i;
 
        for (name in attrs) {
            if ((attribute = attrs[name]) && attribute.transition === anim) {
                d = attribute.duration;
                delay = attribute.delay;
                elapsed = (time - delay) / 1000;
                t = time;
                data = {
                    type: 'propertyEnd',
                    propertyName: name,
                    config: config,
                    elapsedTime: elapsed
                };
 
                setter = (i in customAttr && 'set' in customAttr[i]) ?
                        customAttr[i].set : Transition.DEFAULT_SETTER;
 
                done = (t >= d);
 
                if (t > d) {
                    t = d;
                }
 
                if (!delay || time >= delay) {
                    setter(anim, name, attribute.from, attribute.to, t - delay, d - delay,
                        attribute.easing, attribute.unit);
 
                    if (done) {
                        delete attrs[name];
                        anim._count--;
 
                        if (config[name] && config[name].on && config[name].on.end) {
                            config[name].on.end.call(Y.one(node), data);
                        }
 
                        //node.fire('transition:propertyEnd', data);
 
                        if (!allDone && anim._count <= 0) {
                            allDone = true;
                            anim._end(elapsed);
                            anim._endTimer();
                        }
                    }
                }
 
            }
        }
    },
 
    _initAttrs: function() {
        var anim = this,
            customAttr = Transition.behaviors,
            uid = Y.stamp(anim._node),
            attrs = Transition._nodeAttrs[uid],
            attribute,
            duration,
            delay,
            easing,
            val,
            name,
            mTo,
            mFrom,
            unit, begin, end;
 
        for (name in attrs) {
            if ((attribute = attrs[name]) && attribute.transition === anim) {
                duration = attribute.duration * 1000;
                delay = attribute.delay * 1000;
                easing = attribute.easing;
                val = attribute.value;
 
                // only allow supported properties
                if (name in anim._node.style || name in Y.DOM.CUSTOM_STYLES) {
                    begin = (name in customAttr && 'get' in customAttr[name])  ?
                            customAttr[name].get(anim, name) : Transition.DEFAULT_GETTER(anim, name);
 
                    mFrom = Transition.RE_UNITS.exec(begin);
                    mTo = Transition.RE_UNITS.exec(val);
 
                    begin = mFrom ? mFrom[1] : begin;
                    end = mTo ? mTo[1] : val;
                    unit = mTo ? mTo[2] : mFrom ?  mFrom[2] : ''; // one might be zero TODO: mixed units
 
                    if (!unit && Transition.RE_DEFAULT_UNIT.test(name)) {
                        unit = Transition.DEFAULT_UNIT;
                    }
 
                    if (typeof easing === 'string') {
                        if (easing.indexOf('cubic-bezier') > -1) {
                            easing = easing.substring(13, easing.length - 1).split(',');
                        } else if (Transition.easings[easing]) {
                            easing = Transition.easings[easing];
                        }
                    }
 
                    attribute.from = Number(begin);
                    attribute.to = Number(end);
                    attribute.unit = unit;
                    attribute.easing = easing;
                    attribute.duration = duration + delay;
                    attribute.delay = delay;
                } else {
                    delete attrs[name];
                    anim._count--;
                }
            }
        }
    },
 
    destroy: function() {
        this.detachAll();
        this._node = null;
    }
}, true);
 
Y.mix(Y.Transition, {
    _runtimeAttrs: {},
    /*
     * Regex of properties that should use the default unit.
     *
     * @property RE_DEFAULT_UNIT
     * @static
     */
    RE_DEFAULT_UNIT: /^width|height|top|right|bottom|left|margin.*|padding.*|border.*$/i,
 
    /*
     * The default unit to use with properties that pass the RE_DEFAULT_UNIT test.
     *
     * @property DEFAULT_UNIT
     * @static
     */
    DEFAULT_UNIT: 'px',
 
    /*
     * Time in milliseconds passed to setInterval for frame processing
     *
     * @property intervalTime
     * @default 20
     * @static
     */
    intervalTime: 20,
 
    /*
     * Bucket for custom getters and setters
     *
     * @property behaviors
     * @static
     */
    behaviors: {
        left: {
            get: function(anim, attr) {
                return Y.DOM._getAttrOffset(anim._node, attr);
            }
        }
    },
 
    /*
     * The default setter to use when setting object properties.
     *
     * @property DEFAULT_SETTER
     * @static
     */
    DEFAULT_SETTER: function(anim, att, from, to, elapsed, duration, fn, unit) {
        from = Number(from);
        to = Number(to);
 
        var node = anim._node,
            val = Transition.cubicBezier(fn, elapsed / duration);
 
        val = from + val[0] * (to - from);
 
        if (node) {
            if (att in node.style || att in Y.DOM.CUSTOM_STYLES) {
                unit = unit || '';
                Y.DOM.setStyle(node, att, val + unit);
            }
        } else {
            anim._end();
        }
    },
 
    /*
     * The default getter to use when getting object properties.
     *
     * @property DEFAULT_GETTER
     * @static
     */
    DEFAULT_GETTER: function(anim, att) {
        var node = anim._node,
            val = '';
 
        if (att in node.style || att in Y.DOM.CUSTOM_STYLES) {
            val = Y.DOM.getComputedStyle(node, att);
        }
 
        return val;
    },
 
    _startTimer: function() {
        if (!Transition._timer) {
            Transition._timer = setInterval(Transition._runFrame, Transition.intervalTime);
        }
    },
 
    _stopTimer: function() {
        clearInterval(Transition._timer);
        Transition._timer = null;
    },
 
    /*
     * Called per Interval to handle each animation frame.
     * @method _runFrame
     * @private
     * @static
     */
    _runFrame: function() {
        var done = true,
            anim;
        for (anim in Transition._running) {
            if (Transition._running[anim]._runFrame) {
                done = false;
                Transition._running[anim]._runFrame();
            }
        }
 
        if (done) {
            Transition._stopTimer();
        }
    },
 
    cubicBezier: function(p, t) {
        var x0 = 0,
            y0 = 0,
            x1 = p[0],
            y1 = p[1],
            x2 = p[2],
            y2 = p[3],
            x3 = 1,
            y3 = 0,
 
            A = x3 - 3 * x2 + 3 * x1 - x0,
            B = 3 * x2 - 6 * x1 + 3 * x0,
            C = 3 * x1 - 3 * x0,
            D = x0,
            E = y3 - 3 * y2 + 3 * y1 - y0,
            F = 3 * y2 - 6 * y1 + 3 * y0,
            G = 3 * y1 - 3 * y0,
            H = y0,
 
            x = (((A*t) + B)*t + C)*t + D,
            y = (((E*t) + F)*t + G)*t + H;
 
        return [x, y];
    },
 
    easings: {
        ease: [0.25, 0, 1, 0.25],
        linear: [0, 0, 1, 1],
        'ease-in': [0.42, 0, 1, 1],
        'ease-out': [0, 0, 0.58, 1],
        'ease-in-out': [0.42, 0, 0.58, 1]
    },
 
    _running: {},
    _timer: null,
 
    RE_UNITS: /^(-?\d*\.?\d*){1}(em|ex|px|in|cm|mm|pt|pc|%)*$/
}, true);
 
Transition.behaviors.top = Transition.behaviors.bottom = Transition.behaviors.right = Transition.behaviors.left;
 
Y.Transition = Transition;