/*

YUI 3.10.3 (build 2fb5187)

Copyright 2013 Yahoo! Inc. All rights reserved.

Licensed under the BSD License.

http://yuilibrary.com/license/

*/

YUI.add('node-flick', function (Y, NAME) {

/**

 * Provide a simple Flick plugin, which can be used along with the "flick" gesture event, to 

 * animate the motion of the host node in response to a (mouse or touch) flick gesture. 

 * 

 * <p>The current implementation is designed to move the node, relative to the bounds of a parent node and is suitable

 * for scroll/carousel type implementations. Future versions will remove that constraint, to allow open ended movement within

 * the document.</p>

 *

 * @module node-flick

 */

    var HOST = "host",

        PARENT_NODE = "parentNode",

        BOUNDING_BOX = "boundingBox",

        OFFSET_HEIGHT = "offsetHeight",

        OFFSET_WIDTH = "offsetWidth",

        SCROLL_HEIGHT = "scrollHeight",

        SCROLL_WIDTH = "scrollWidth",

        BOUNCE = "bounce",

        MIN_DISTANCE = "minDistance",

        MIN_VELOCITY = "minVelocity",

        BOUNCE_DISTANCE = "bounceDistance",

        DECELERATION = "deceleration",

        STEP = "step",

        DURATION = "duration",

        EASING = "easing",

        FLICK = "flick",

        getClassName = Y.ClassNameManager.getClassName;

    /**

     * A plugin class which can be used to animate the motion of a node, in response to a flick gesture.

     * 

     * @class Flick

     * @namespace Plugin

     * @param {Object} config The initial attribute values for the plugin

     */

    function Flick(config) {

        Flick.superclass.constructor.apply(this, arguments);

    }

    Flick.ATTRS = {

        /**

         * Drag coefficent for inertial scrolling. The closer to 1 this

         * value is, the less friction during scrolling.

         *

         * @attribute deceleration

         * @default 0.98

         */

        deceleration : {

            value: 0.98

        },

        /**

         * Drag coefficient for intertial scrolling at the upper

         * and lower boundaries of the scrollview. Set to 0 to 

         * disable "rubber-banding".

         *

         * @attribute bounce

         * @type Number

         * @default 0.7

         */

        bounce : {

            value: 0.7

        },

        /**

         * The bounce distance in pixels

         *

         * @attribute bounceDistance

         * @type Number

         * @default 150

         */

        bounceDistance : {

            value: 150

        },

        /**

         * The minimum flick gesture velocity (px/ms) at which to trigger the flick response

         *

         * @attribute minVelocity

         * @type Number

         * @default 0

         */

        minVelocity : {

            value: 0

        },

        /**

         * The minimum flick gesture distance (px) for which to trigger the flick response

         *

         * @attribute minVelocity

         * @type Number

         * @default 10

         */

        minDistance : {

            value: 10

        },

        /**

         * The constraining box relative to which the flick animation and bounds should be calculated.

         *

         * @attribute boundingBox

         * @type Node

         * @default parentNode

         */

        boundingBox : {

            valueFn : function() {

                return this.get(HOST).get(PARENT_NODE);

            }

        },

        /**

         * Time between flick animation frames.

         *

         * @attribute step

         * @type Number

         * @default 10

         */

        step : {

            value:10

        },

        /**

         * The custom duration to apply to the flick animation. By default,

         * the animation duration is controlled by the deceleration factor.

         *

         * @attribute duration

         * @type Number

         * @default null

         */

        duration : {

            value:null

        },

        /**

         * The custom transition easing to use for the flick animation. If not

         * provided defaults to internally to Flick.EASING, or Flick.SNAP_EASING based

         * on whether or not we're animating the flick or bounce step. 

         *

         * @attribute easing

         * @type String

         * @default null

         */

        easing : {

            value:null

        }

    };

    /**

     * The NAME of the Flick class. Used to prefix events generated

     * by the plugin.

     *

     * @property NAME

     * @static

     * @type String

     * @default "pluginFlick"

     */

    Flick.NAME = "pluginFlick";

    /**

     * The namespace for the plugin. This will be the property on the node, which will 

     * reference the plugin instance, when it's plugged in.

     *

     * @property NS

     * @static

     * @type String

     * @default "flick"

     */

    Flick.NS = "flick";

    Y.extend(Flick, Y.Plugin.Base, {

        /**

         * The initializer lifecycle implementation.

         *

         * @method initializer

         * @param {Object} config The user configuration for the plugin  

         */

        initializer : function(config) {

            this._node = this.get(HOST);

            this._renderClasses();

            this.setBounds();

            this._node.on(FLICK, Y.bind(this._onFlick, this), {

                minDistance : this.get(MIN_DISTANCE),

                minVelocity : this.get(MIN_VELOCITY)

            });

        },

        /**

         * Sets the min/max boundaries for the flick animation,

         * based on the boundingBox dimensions.

         * 

         * @method setBounds

         */

        setBounds : function () {

            var box = this.get(BOUNDING_BOX),

                node = this._node,

                boxHeight = box.get(OFFSET_HEIGHT),

                boxWidth = box.get(OFFSET_WIDTH),

                contentHeight = node.get(SCROLL_HEIGHT),

                contentWidth = node.get(SCROLL_WIDTH);

            if (contentHeight > boxHeight) {

                this._maxY = contentHeight - boxHeight;

                this._minY = 0;

                this._scrollY = true;

            }

            if (contentWidth > boxWidth) {

                this._maxX = contentWidth - boxWidth;

                this._minX = 0;

                this._scrollX = true;

            }

            this._x = this._y = 0;

            node.set("top", this._y + "px");

            node.set("left", this._x + "px");

        },

        /**

         * Adds the CSS classes, necessary to set up overflow/position properties on the

         * node and boundingBox. 

         *

         * @method _renderClasses

         * @protected

         */

        _renderClasses : function() {

            this.get(BOUNDING_BOX).addClass(Flick.CLASS_NAMES.box);

            this._node.addClass(Flick.CLASS_NAMES.content);

        },

        /**

         * The flick event listener. Kicks off the flick animation.

         *

         * @method _onFlick

         * @param e {EventFacade} The flick event facade, containing e.flick.distance, e.flick.velocity etc.

         * @protected

         */

        _onFlick: function(e) {

            this._v = e.flick.velocity;

            this._flick = true;

            this._flickAnim();

        },

        /**

         * Executes a single frame in the flick animation

         *

         * @method _flickFrame

         * @protected

         */

        _flickAnim: function() {

            var y = this._y,

                x = this._x,

                maxY = this._maxY,

                minY = this._minY,

                maxX = this._maxX,

                minX = this._minX,

                velocity = this._v,

                step = this.get(STEP),

                deceleration = this.get(DECELERATION),

                bounce = this.get(BOUNCE);

            this._v = (velocity * deceleration);

            this._snapToEdge = false;

            if (this._scrollX) {

                x = x - (velocity * step);

            }

            if (this._scrollY) {

                y = y - (velocity * step);

            }

            if (Math.abs(velocity).toFixed(4) <= Flick.VELOCITY_THRESHOLD) {

                this._flick = false;

                this._killTimer(!(this._exceededYBoundary || this._exceededXBoundary));

                if (this._scrollX) {

                    if (x < minX) {

                        this._snapToEdge = true;

                        this._setX(minX);

                    } else if (x > maxX) {

                        this._snapToEdge = true;

                        this._setX(maxX);

                    }

                }

                if (this._scrollY) {

                    if (y < minY) {

                        this._snapToEdge = true;

                        this._setY(minY);

                    } else if (y > maxY) {

                        this._snapToEdge = true;

                        this._setY(maxY);

                    }

                }

            } else {

                if (this._scrollX && (x < minX || x > maxX)) {

                    this._exceededXBoundary = true;

                    this._v *= bounce;

                }

                if (this._scrollY && (y < minY || y > maxY)) {

                    this._exceededYBoundary = true;

                    this._v *= bounce;

                }

                if (this._scrollX) {

                    this._setX(x);

                }

                if (this._scrollY) {

                    this._setY(y);

                }

                this._flickTimer = Y.later(step, this, this._flickAnim);

            }

        },

        /**

         * Internal utility method to set the X offset position

         *

         * @method _setX

         * @param {Number} val

         * @private

         */

        _setX : function(val) {

            this._move(val, null, this.get(DURATION), this.get(EASING));

        },

        /**

         * Internal utility method to set the Y offset position

         * 

         * @method _setY

         * @param {Number} val

         * @private

         */

        _setY : function(val) {

            this._move(null, val, this.get(DURATION), this.get(EASING));

        },

        /**

         * Internal utility method to move the node to a given XY position,

         * using transitions, if specified.

         *

         * @method _move

         * @param {Number} x The X offset position

         * @param {Number} y The Y offset position

         * @param {Number} duration The duration to use for the transition animation

         * @param {String} easing The easing to use for the transition animation.

         *

         * @private

         */

        _move: function(x, y, duration, easing) {

            if (x !== null) {

                x = this._bounce(x);

            } else {

                x = this._x; 

            }

            if (y !== null) {

                y = this._bounce(y);

            } else {

                y = this._y;

            }

            duration = duration || this._snapToEdge ? Flick.SNAP_DURATION : 0;

            easing = easing || this._snapToEdge ? Flick.SNAP_EASING : Flick.EASING;

            this._x = x;

            this._y = y;

            this._anim(x, y, duration, easing);

        },

        /**

         * Internal utility method to perform the transition step

         *

         * @method _anim

         * @param {Number} x The X offset position

         * @param {Number} y The Y offset position

         * @param {Number} duration The duration to use for the transition animation

         * @param {String} easing The easing to use for the transition animation.

         *

         * @private

         */

        _anim : function(x, y, duration, easing) {

            var xn = x * -1,