/*

Copyright (c) 2009, Yahoo! Inc. All rights reserved.

Code licensed under the BSD License:

http://developer.yahoo.net/yui/license.txt

version: 3.0.0b1

build: 1163

*/

YUI.add('anim-base', function(Y) {

/**

* The Animation Utility provides an API for creating advanced transitions.

* @module anim

*/

/**

* Provides the base Anim class, for animating numeric properties.

*

* @module anim

* @submodule anim-base

*/

    /**

     * A class for constructing animation instances.

     * @class Anim

     * @for Anim

     * @constructor

     * @extends Base

     */

    var RUNNING = 'running',

        START_TIME = 'startTime',

        ELAPSED_TIME = 'elapsedTime',

        /**

        * @for Anim

        * @event start

        * @description fires when an animation begins.

        * @param {Event} ev The start event.

        * @type Event.Custom

        */

        START = 'start',

        /**

        * @event tween

        * @description fires every frame of the animation.

        * @param {Event} ev The tween event.

        * @type Event.Custom

        */

        TWEEN = 'tween',

        /**

        * @event end

        * @description fires after the animation completes.

        * @param {Event} ev The end event.

        * @type Event.Custom

        */

        END = 'end',

        NODE = 'node',

        PAUSED = 'paused',

        REVERSE = 'reverse', // TODO: cleanup

        ITERATION_COUNT = 'iterationCount',

        NUM = Number;

    var _running = {},

        _instances = {},

        _timer;

    Y.Anim = function() {

        Y.Anim.superclass.constructor.apply(this, arguments);

        _instances[Y.stamp(this)] = this;

    };

    Y.Anim.NAME = 'anim';

    /**

     * Regex of properties that should use the default unit.

     *

     * @property RE_DEFAULT_UNIT

     * @static

     */

    Y.Anim.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

     */

    Y.Anim.DEFAULT_UNIT = 'px';

    Y.Anim.DEFAULT_EASING = function (t, b, c, d) {

        return c * t / d + b; // linear easing

    };

    /**

     * Bucket for custom getters and setters

     *

     * @property behaviors

     * @static

     */

    Y.Anim.behaviors = {

        left: {

            get: function(anim, attr) {

                return anim._getOffset(attr);

            }

        }

    };

    Y.Anim.behaviors.top = Y.Anim.behaviors.left;

    /**

     * The default setter to use when setting object properties.

     *

     * @property DEFAULT_SETTER

     * @static

     */

    Y.Anim.DEFAULT_SETTER = function(anim, att, from, to, elapsed, duration, fn, unit) {

        unit = unit || '';

        anim._node.setStyle(att, fn(elapsed, NUM(from), NUM(to) - NUM(from), duration) + unit);

    };

    /**

     * The default getter to use when getting object properties.

     *

     * @property DEFAULT_GETTER

     * @static

     */

    Y.Anim.DEFAULT_GETTER = function(anim, prop) {

        return anim._node.getComputedStyle(prop);

    };

    Y.Anim.ATTRS = {

        /**

         * The object to be animated.

         * @attribute node

         * @type Node

         */

        node: {

            setter: function(node) {

                node = Y.get(node);

                this._node = node;

                if (!node) {

                    Y.log(node + ' is not a valid node', 'warn', 'Anim');

                }

                return node;

            }

        },

        /**

         * The length of the animation.  Defaults to "1" (second).

         * @attribute duration

         * @type NUM

         */

        duration: {

            value: 1

        },

        /**

         * The method that will provide values to the attribute(s) during the animation. 

         * Defaults to "Easing.easeNone".

         * @attribute easing

         * @type Function

         */

        easing: {

            value: Y.Anim.DEFAULT_EASING,

            setter: function(val) {

                if (typeof val === 'string' && Y.Easing) {

                    return Y.Easing[val];

                }

            }

        },

        /**

         * The starting values for the animated properties. 

         * Fields may be strings, numbers, or functions.

         * If a function is used, the return value becomes the from value.

         * If no from value is specified, the DEFAULT_GETTER will be used. 

         * @attribute from

         * @type Object

         */

        from: {},

        /**

         * The ending values for the animated properties. 

         * Fields may be strings, numbers, or functions.

         * @attribute to

         * @type Object

         */

        to: {},

        /**

         * Date stamp for the first frame of the animation.

         * @attribute startTime

         * @type Int

         * @default 0 

         * @readOnly

         */

        startTime: {

            value: 0,

            readOnly: true

        },

        /**

         * Current time the animation has been running.

         * @attribute elapsedTime

         * @type Int

         * @default 0 

         * @readOnly

         */

        elapsedTime: {

            value: 0,

            readOnly: true

        },

        /**

         * Whether or not the animation is currently running.

         * @attribute running 

         * @type Boolean

         * @default false 

         * @readOnly

         */

        running: {

            getter: function() {

                return !!_running[Y.stamp(this)];

            },

            value: false,

            readOnly: true

        },

        /**

         * The number of times the animation should run 

         * @attribute iterations

         * @type Int

         * @default 1 

         */

        iterations: {

            value: 1

        },

        /**

         * The number of iterations that have occurred.

         * Resets when an animation ends (reaches iteration count or stop() called). 

         * @attribute iterationCount

         * @type Int

         * @default 0

         * @readOnly

         */

        iterationCount: {

            value: 0,

            readOnly: true

        },

        /**

         * How iterations of the animation should behave. 

         * Possible values are "normal" and "alternate".

         * Normal will repeat the animation, alternate will reverse on every other pass.

         *

         * @attribute direction

         * @type String

         * @default "normal"

         */

        direction: {

            value: 'normal' // | alternate (fwd on odd, rev on even per spec)

        },

        /**

         * Whether or not the animation is currently paused.

         * @attribute running 

         * @type Boolean

         * @default false 

         * @readOnly

         */

        paused: {

            readOnly: true,

            value: false

        },

        /**

         * If true, animation begins from last frame

         * @attribute reverse

         * @type Boolean

         * @default false 

         */

        reverse: {

            value: false

        }

    };

    /**

     * Runs all animation instances.

     * @method run

     * @static

     */    

    Y.Anim.run = function() {

        for (var i in _instances) {

            if (_instances[i].run) {

                _instances[i].run();

            }

        }

    };

    /**

     * Pauses all animation instances.

     * @method pause

     * @static

     */    

    Y.Anim.pause = function() {

        for (var i in _running) { // stop timer if nothing running

            if (_running[i].pause) {

                _running[i].pause();

            }

        }

        Y.Anim._stopTimer();

    };

    /**

     * Stops all animation instances.

     * @method stop

     * @static

     */    

    Y.Anim.stop = function() {

        for (var i in _running) { // stop timer if nothing running

            if (_running[i].stop) {

                _running[i].stop();

            }

        }

        Y.Anim._stopTimer();

    };

    Y.Anim._startTimer = function() {

        if (!_timer) {

            _timer = setInterval(Y.Anim._runFrame, 1);

        }

    };

    Y.Anim._stopTimer = function() {

        clearInterval(_timer);

        _timer = 0;

    };

    /**

     * Called per Interval to handle each animation frame.

     * @method _runFrame

     * @private

     * @static

     */    

    Y.Anim._runFrame = function() {

        var done = true;

        for (var anim in _running) {

            if (_running[anim]._runFrame) {

                done = false;

                _running[anim]._runFrame();

            }

        }

        if (done) {

            Y.Anim._stopTimer();

        }

    };

    Y.Anim.RE_UNITS = /^(-?\d*\.?\d*){1}(em|ex|px|in|cm|mm|pt|pc|%)*$/;

    var proto = {

        /**

         * Starts or resumes an animation.

         * percent start time marker.

         * @method run

         * @chainable

         */    

        run: function() {

            if (!this.get(RUNNING)) {

                this._start();

            } else if (this.get(PAUSED)) {

                this._resume();

            }

            return this;

        },

        /**

         * Pauses the animation and

         * freezes it in its current state and time.

         * Calling run() will continue where it left off.

         * @method pause

         * @chainable

         */    

        pause: function() {

            if (this.get(RUNNING)) {

                this._pause();

            }

            return this;

        },

        /**

         * Stops the animation and resets its time.

         * @method stop

         * @chainable

         */    

        stop: function(finish) {

            if (this.get(RUNNING) || this.get(PAUSED)) {

                this._end(finish);

            }

            return this;

        },

        _added: false,

        _start: function() {

            this._set(START_TIME, new Date() - this.get(ELAPSED_TIME));

            this._actualFrames = 0;

            if (!this.get(PAUSED)) {

                this._initAnimAttr();

            }

            _running[Y.stamp(this)] = this;

            Y.Anim._startTimer();

            this.fire(START);

        },

        _pause: function() {

            this._set(START_TIME, null);

            this._set(PAUSED, true);