/**
 * The YUI module contains the components required for building the YUI
 * seed file.  This includes the script loading mechanism, a simple queue,
 * and the core utilities for the library.
 * @module yui
 * @submodule yui-base
 */

/**
 * A simple FIFO queue.  Items are added to the Queue with add(1..n items) and
 * removed using next().
 *
 * @class Queue
 * @constructor
 * @param {MIXED} item* 0..n items to seed the queue.
 */
function Queue() {
    this._init();
    this.add.apply(this, arguments);
}

Queue.prototype = {
    /**
     * Initialize the queue
     *
     * @method _init
     * @protected
     */
    _init: function() {
        /**
         * The collection of enqueued items
         *
         * @property _q
         * @type Array
         * @protected
         */
        this._q = [];
    },

    /**
     * Get the next item in the queue. FIFO support
     *
     * @method next
     * @return {MIXED} the next item in the queue.
     */
    next: function() {
        return this._q.shift();
    },

    /**
     * Get the last in the queue. LIFO support.
     *
     * @method last
     * @return {MIXED} the last item in the queue.
     */
    last: function() {
        return this._q.pop();
    },

    /**
     * Add 0..n items to the end of the queue.
     *
     * @method add
     * @param {MIXED} item* 0..n items.
     * @return {object} this queue.
     */
    add: function() {
        this._q.push.apply(this._q, arguments);

        return this;
    },

    /**
     * Returns the current number of queued items.
     *
     * @method size
     * @return {Number} The size.
     */
    size: function() {
        return this._q.length;
    }
};

Y.Queue = Queue;

YUI.Env._loaderQueue = YUI.Env._loaderQueue || new Queue();