/**
 * The selector module provides helper methods allowing CSS2 Selectors to be used with DOM elements.
 * @module dom
 * @submodule selector-css2
 * @for Selector
 */
 
/*
 * Provides helper methods for collecting and filtering DOM elements.
 */
 
var PARENT_NODE = 'parentNode',
    TAG_NAME = 'tagName',
    ATTRIBUTES = 'attributes',
    COMBINATOR = 'combinator',
    PSEUDOS = 'pseudos',
 
    Selector = Y.Selector,
 
    SelectorCSS2 = {
        _reRegExpTokens: /([\^\$\?\[\]\*\+\-\.\(\)\|\\])/,
        SORT_RESULTS: true,
 
        // TODO: better detection, document specific
        _isXML: (function() {
            var isXML = (Y.config.doc.createElement('div').tagName !== 'DIV');
            return isXML;
        }()),
 
        /**
         * Mapping of shorthand tokens to corresponding attribute selector
         * @property shorthand
         * @type object
         */
        shorthand: {
            '\\#(-?[_a-z0-9]+[-\\w\\uE000]*)': '[id=$1]',
            '\\.(-?[_a-z]+[-\\w\\uE000]*)': '[className~=$1]'
        },
 
        /**
         * List of operators and corresponding boolean functions.
         * These functions are passed the attribute and the current node's value of the attribute.
         * @property operators
         * @type object
         */
        operators: {
            '': function(node, attr) { return Y.DOM.getAttribute(node, attr) !== ''; }, // Just test for existence of attribute
            '~=': '(?:^|\\s+){val}(?:\\s+|$)', // space-delimited
            '|=': '^{val}-?' // optional hyphen-delimited
        },
 
        pseudos: {
           'first-child': function(node) {
                return Y.DOM._children(node[PARENT_NODE])[0] === node;
            }
        },
 
        _bruteQuery: function(selector, root, firstOnly) {
            var ret = [],
                nodes = [],
                visited,
                tokens = Selector._tokenize(selector),
                token = tokens[tokens.length - 1],
                rootDoc = Y.DOM._getDoc(root),
                child,
                id,
                className,
                tagName,
                isUniversal;
 
            if (token) {
                // prefilter nodes
                id = token.id;
                className = token.className;
                tagName = token.tagName || '*';
 
                if (root.getElementsByTagName) { // non-IE lacks DOM api on doc frags
                    // try ID first, unless no root.all && root not in document
                    // (root.all works off document, but not getElementById)
                    if (id && (root.all || (root.nodeType === 9 || Y.DOM.inDoc(root)))) {
                        nodes = Y.DOM.allById(id, root);
                    // try className
                    } else if (className) {
                        nodes = root.getElementsByClassName(className);
                    } else { // default to tagName
                        nodes = root.getElementsByTagName(tagName);
                    }
 
                } else { // brute getElementsByTagName()
                    visited = [];
                    child = root.firstChild;
                    isUniversal = tagName === "*";
                    while (child) {
                        while (child) {
                            // IE 6-7 considers comment nodes as element nodes, and gives them the tagName "!".
                            // We can filter them out by checking if its tagName is > "@".
                            // This also avoids a superflous nodeType === 1 check.
                            if (child.tagName > "@" && (isUniversal || child.tagName === tagName)) {
                                nodes.push(child);
                            }
 
                            // We may need to traverse back up the tree to find more unvisited subtrees.
                            visited.push(child);
                            child = child.firstChild;
                        }
 
                        // Find the most recently visited node who has a next sibling.
                        while (visited.length > 0 && !child) {
                            child = visited.pop().nextSibling;
                        }
                    }
                }
 
                if (nodes.length) {
                    ret = Selector._filterNodes(nodes, tokens, firstOnly);
                }
            }
 
            return ret;
        },
 
        _filterNodes: function(nodes, tokens, firstOnly) {
            var i = 0,
                j,
                len = tokens.length,
                n = len - 1,
                result = [],
                node = nodes[0],
                tmpNode = node,
                getters = Y.Selector.getters,
                operator,
                combinator,
                token,
                path,
                pass,
                value,
                tests,
                test;
 
            for (i = 0; (tmpNode = node = nodes[i++]);) {
                n = len - 1;
                path = null;
 
                testLoop:
                while (tmpNode && tmpNode.tagName) {
                    token = tokens[n];
                    tests = token.tests;
                    j = tests.length;
                    if (j && !pass) {
                        while ((test = tests[--j])) {
                            operator = test[1];
                            if (getters[test[0]]) {
                                value = getters[test[0]](tmpNode, test[0]);
                            } else {
                                value = tmpNode[test[0]];
                                if (test[0] === 'tagName' && !Selector._isXML) {
                                    value = value.toUpperCase();
                                }
                                if (typeof value != 'string' && value !== undefined && value.toString) {
                                    value = value.toString(); // coerce for comparison
                                } else if (value === undefined && tmpNode.getAttribute) {
                                    // use getAttribute for non-standard attributes
                                    value = tmpNode.getAttribute(test[0], 2); // 2 === force string for IE
                                }
                            }
 
                            if ((operator === '=' && value !== test[2]) ||  // fast path for equality
                                (typeof operator !== 'string' && // protect against String.test monkey-patch (Moo)
                                operator.test && !operator.test(value)) ||  // regex test
                                (!operator.test && // protect against RegExp as function (webkit)
                                        typeof operator === 'function' && !operator(tmpNode, test[0], test[2]))) { // function test
 
                                // skip non element nodes or non-matching tags
                                if ((tmpNode = tmpNode[path])) {
                                    while (tmpNode &&
                                        (!tmpNode.tagName ||
                                            (token.tagName && token.tagName !== tmpNode.tagName))
                                    ) {
                                        tmpNode = tmpNode[path];
                                    }
                                }
                                continue testLoop;
                            }
                        }
                    }
 
                    n--; // move to next token
                    // now that we've passed the test, move up the tree by combinator
                    if (!pass && (combinator = token.combinator)) {
                        path = combinator.axis;
                        tmpNode = tmpNode[path];
 
                        // skip non element nodes
                        while (tmpNode && !tmpNode.tagName) {
                            tmpNode = tmpNode[path];
                        }
 
                        if (combinator.direct) { // one pass only
                            path = null;
                        }
 
                    } else { // success if we made it this far
                        result.push(node);
                        if (firstOnly) {
                            return result;
                        }
                        break;
                    }
                }
            }
            node = tmpNode = null;
            return result;
        },
 
        combinators: {
            ' ': {
                axis: 'parentNode'
            },
 
            '>': {
                axis: 'parentNode',
                direct: true
            },
 
 
            '+': {
                axis: 'previousSibling',
                direct: true
            }
        },
 
        _parsers: [
            {
                name: ATTRIBUTES,
                re: /^\uE003(-?[a-z]+[\w\-]*)+([~\|\^\$\*!=]=?)?['"]?([^\uE004'"]*)['"]?\uE004/i,
                fn: function(match, token) {
                    var operator = match[2] || '',
                        operators = Selector.operators,
                        escVal = (match[3]) ? match[3].replace(/\\/g, '') : '',
                        test;
 
                    // add prefiltering for ID and CLASS
                    if ((match[1] === 'id' && operator === '=') ||
                            (match[1] === 'className' &&
                            Y.config.doc.documentElement.getElementsByClassName &&
                            (operator === '~=' || operator === '='))) {
                        token.prefilter = match[1];
 
 
                        match[3] = escVal;
 
                        // escape all but ID for prefilter, which may run through QSA (via Dom.allById)
                        token[match[1]] = (match[1] === 'id') ? match[3] : escVal;
 
                    }
 
                    // add tests
                    if (operator in operators) {
                        test = operators[operator];
                        if (typeof test === 'string') {
                            match[3] = escVal.replace(Selector._reRegExpTokens, '\\$1');
                            test = new RegExp(test.replace('{val}', match[3]));
                        }
                        match[2] = test;
                    }
                    if (!token.last || token.prefilter !== match[1]) {
                        return match.slice(1);
                    }
                }
            },
            {
                name: TAG_NAME,
                re: /^((?:-?[_a-z]+[\w-]*)|\*)/i,
                fn: function(match, token) {
                    var tag = match[1];
 
                    if (!Selector._isXML) {
                        tag = tag.toUpperCase();
                    }
 
                    token.tagName = tag;
 
                    if (tag !== '*' && (!token.last || token.prefilter)) {
                        return [TAG_NAME, '=', tag];
                    }
                    if (!token.prefilter) {
                        token.prefilter = 'tagName';
                    }
                }
            },
            {
                name: COMBINATOR,
                re: /^\s*([>+~]|\s)\s*/,
                fn: function(match, token) {
                }
            },
            {
                name: PSEUDOS,
                re: /^:([\-\w]+)(?:\uE005['"]?([^\uE005]*)['"]?\uE006)*/i,
                fn: function(match, token) {
                    var test = Selector[PSEUDOS][match[1]];
                    if (test) { // reorder match array and unescape special chars for tests
                        if (match[2]) {
                            match[2] = match[2].replace(/\\/g, '');
                        }
                        return [match[2], test];
                    } else { // selector token not supported (possibly missing CSS3 module)
                        return false;
                    }
                }
            }
            ],
 
        _getToken: function(token) {
            return {
                tagName: null,
                id: null,
                className: null,
                attributes: {},
                combinator: null,
                tests: []
            };
        },
 
        /*
            Break selector into token units per simple selector.
            Combinator is attached to the previous token.
         */
        _tokenize: function(selector) {
            selector = selector || '';
            selector = Selector._parseSelector(Y.Lang.trim(selector));
            var token = Selector._getToken(),     // one token per simple selector (left selector holds combinator)
                query = selector, // original query for debug report
                tokens = [],    // array of tokens
                found = false,  // whether or not any matches were found this pass
                match,         // the regex match
                test,
                i, parser;
 
            /*
                Search for selector patterns, store, and strip them from the selector string
                until no patterns match (invalid selector) or we run out of chars.
 
                Multiple attributes and pseudos are allowed, in any order.
                for example:
                    'form:first-child[type=button]:not(button)[lang|=en]'
            */
            outer:
            do {
                found = false; // reset after full pass
                for (i = 0; (parser = Selector._parsers[i++]);) {
                    if ( (match = parser.re.exec(selector)) ) { // note assignment
                        if (parser.name !== COMBINATOR ) {
                            token.selector = selector;
                        }
                        selector = selector.replace(match[0], ''); // strip current match from selector
                        if (!selector.length) {
                            token.last = true;
                        }
 
                        if (Selector._attrFilters[match[1]]) { // convert class to className, etc.
                            match[1] = Selector._attrFilters[match[1]];
                        }
 
                        test = parser.fn(match, token);
                        if (test === false) { // selector not supported
                            found = false;
                            break outer;
                        } else if (test) {
                            token.tests.push(test);
                        }
 
                        if (!selector.length || parser.name === COMBINATOR) {
                            tokens.push(token);
                            token = Selector._getToken(token);
                            if (parser.name === COMBINATOR) {
                                token.combinator = Y.Selector.combinators[match[1]];
                            }
                        }
                        found = true;
                    }
                }
            } while (found && selector.length);
 
            if (!found || selector.length) { // not fully parsed
                Y.log('query: ' + query + ' contains unsupported token in: ' + selector, 'warn', 'Selector');
                tokens = [];
            }
            return tokens;
        },
 
        _replaceMarkers: function(selector) {
            selector = selector.replace(/\[/g, '\uE003');
            selector = selector.replace(/\]/g, '\uE004');
 
            selector = selector.replace(/\(/g, '\uE005');
            selector = selector.replace(/\)/g, '\uE006');
            return selector;
        },
 
        _replaceShorthand: function(selector) {
            var shorthand = Y.Selector.shorthand,
                re;
 
            for (re in shorthand) {
                if (shorthand.hasOwnProperty(re)) {
                    selector = selector.replace(new RegExp(re, 'gi'), shorthand[re]);
                }
            }
 
            return selector;
        },
 
        _parseSelector: function(selector) {
            var replaced = Y.Selector._replaceSelector(selector),
                selector = replaced.selector;
 
            // replace shorthand (".foo, #bar") after pseudos and attrs
            // to avoid replacing unescaped chars
            selector = Y.Selector._replaceShorthand(selector);
 
            selector = Y.Selector._restore('attr', selector, replaced.attrs);
            selector = Y.Selector._restore('pseudo', selector, replaced.pseudos);
 
            // replace braces and parens before restoring escaped chars
            // to avoid replacing ecaped markers
            selector = Y.Selector._replaceMarkers(selector);
            selector = Y.Selector._restore('esc', selector, replaced.esc);
 
            return selector;
        },
 
        _attrFilters: {
            'class': 'className',
            'for': 'htmlFor'
        },
 
        getters: {
            href: function(node, attr) {
                return Y.DOM.getAttribute(node, attr);
            },
 
            id: function(node, attr) {
                return Y.DOM.getId(node);
            }
        }
    };
 
Y.mix(Y.Selector, SelectorCSS2, true);
Y.Selector.getters.src = Y.Selector.getters.rel = Y.Selector.getters.href;
 
// IE wants class with native queries
if (Y.Selector.useNative && Y.config.doc.querySelector) {
    Y.Selector.shorthand['\\.(-?[_a-z]+[-\\w]*)'] = '[class~=$1]';
}