/*

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

Code licensed under the BSD License:

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

version: 3.0.0

build: 1549

*/

YUI.add('selector-css3', function(Y) {

/**

 * The selector css3 module provides support for css3 selectors.

 * @module dom

 * @submodule selector-css3

 * @for Selector

 */

/*

    an+b = get every _a_th node starting at the _b_th

    0n+b = no repeat ("0" and "n" may both be omitted (together) , e.g. "0n+1" or "1", not "0+1"), return only the _b_th element

    1n+b =  get every element starting from b ("1" may may be omitted, e.g. "1n+0" or "n+0" or "n")

    an+0 = get every _a_th element, "0" may be omitted 

*/

Y.Selector._reNth = /^(?:([\-]?\d*)(n){1}|(odd|even)$)*([\-+]?\d*)$/;

Y.Selector._getNth = function(node, expr, tag, reverse) {

    Y.Selector._reNth.test(expr);

    var a = parseInt(RegExp.$1, 10), // include every _a_ elements (zero means no repeat, just first _a_)

        n = RegExp.$2, // "n"

        oddeven = RegExp.$3, // "odd" or "even"

        b = parseInt(RegExp.$4, 10) || 0, // start scan from element _b_

        result = [],

        siblings = Y.Selector._children(node.parentNode, tag),

        op;

    if (oddeven) {

        a = 2; // always every other

        op = '+';

        n = 'n';

        b = (oddeven === 'odd') ? 1 : 0;

    } else if ( isNaN(a) ) {

        a = (n) ? 1 : 0; // start from the first or no repeat

    }

    if (a === 0) { // just the first

        if (reverse) {

            b = siblings.length - b + 1; 

        }

        if (siblings[b - 1] === node) {

            return true;

        } else {

            return false;

        }

    } else if (a < 0) {

        reverse = !!reverse;

        a = Math.abs(a);

    }

    if (!reverse) {

        for (var i = b - 1, len = siblings.length; i < len; i += a) {

            if ( i >= 0 && siblings[i] === node ) {

                return true;

            }

        }

    } else {

        for (var i = siblings.length - b, len = siblings.length; i >= 0; i -= a) {

            if ( i < len && siblings[i] === node ) {

                return true;

            }

        }

    }

    return false;

};

Y.mix(Y.Selector.pseudos, {

    'root': function(node) {

        return node === node.ownerDocument.documentElement;

    },

    'nth-child': function(node, expr) {

        return Y.Selector._getNth(node, expr);

    },

    'nth-last-child': function(node, expr) {

        return Y.Selector._getNth(node, expr, null, true);

    },

    'nth-of-type': function(node, expr) {

        return Y.Selector._getNth(node, expr, node.tagName);

    },

    'nth-last-of-type': function(node, expr) {

        return Y.Selector._getNth(node, expr, node.tagName, true);

    },

    'last-child': function(node) {

        var children = Y.Selector._children(node.parentNode);

        return children[children.length - 1] === node;

    },

    'first-of-type': function(node) {

        return Y.Selector._children(node.parentNode, node.tagName)[0] === node;

    },

    'last-of-type': function(node) {

        var children = Y.Selector._children(node.parentNode, node.tagName);

        return children[children.length - 1] === node;

    },

    'only-child': function(node) {

        var children = Y.Selector._children(node.parentNode);

        return children.length === 1 && children[0] === node;

    },

    'only-of-type': function(node) {

        var children = Y.Selector._children(node.parentNode, node.tagName);

        return children.length === 1 && children[0] === node;

    },

    'empty': function(node) {

        return node.childNodes.length === 0;

    },

    'not': function(node, expr) {

        return !Y.Selector.test(node, expr);

    },

    'contains': function(node, expr) {

        var text = node.innerText || node.textContent || '';

        return text.indexOf(expr) > -1;

    },

    'checked': function(node) {

        return node.checked === true;

    }

});

Y.mix(Y.Selector.operators, {

    '^=': '^{val}', // Match starts with value

    '$=': '{val}$', // Match ends with value

    '*=': '{val}' // Match contains value as substring 

});

Y.Selector.combinators['~'] = {

    axis: 'previousSibling'

};

}, '3.0.0' ,{requires:['dom-base', 'selector-native', 'selector-css2']});