/**
 * @class Ext.dom.AbstractQuery
 * @private
 */
Ext.define('Ext.dom.AbstractQuery', {
    /**
     * Selects a group of elements.
     * @param {String} selector The selector/xpath query (can be a comma separated list of selectors)
     * @param {HTMLElement/String} [root] The start of the query (defaults to document).
     * @return {HTMLElement[]} An Array of DOM elements which match the selector. If there are
     * no matches, and empty Array is returned.
     */
    select: function(q, root) {
        var results = [],
            nodes,
            i,
            j,
            qlen,
            nlen;

        root = root || document;

        if (typeof root == 'string') {
            root = document.getElementById(root);
        }

        q = q.split(",");

        for (i = 0,qlen = q.length; i < qlen; i++) {
            if (typeof q[i] == 'string') {
                
                //support for node attribute selection
                if (typeof q[i][0] == '@') {
                    nodes = root.getAttributeNode(q[i].substring(1));
                    results.push(nodes);
                } else {
                    nodes = root.querySelectorAll(q[i]);

                    for (j = 0,nlen = nodes.length; j < nlen; j++) {
                        results.push(nodes[j]);
                    }
                }
            }
        }

        return results;
    },

    /**
     * Selects a single element.
     * @param {String} selector The selector/xpath query
     * @param {HTMLElement/String} [root] The start of the query (defaults to document).
     * @return {HTMLElement} The DOM element which matched the selector.
     */
    selectNode: function(q, root) {
        return this.select(q, root)[0];
    },

    /**
     * Returns true if the passed element(s) match the passed simple selector (e.g. div.some-class or span:first-child)
     * @param {String/HTMLElement/Array} el An element id, element or array of elements
     * @param {String} selector The simple selector to test
     * @return {Boolean}
     */
    is: function(el, q) {
        if (typeof el == "string") {
            el = document.getElementById(el);
        }
        return this.select(q).indexOf(el) !== -1;
    }

});
