/*
    This work is licensed under a Creative Commons License.

    License: http://creativecommons.org/licenses/by/1.0/

    You are free:

    to copy, distribute, display, and perform the work
    to make derivative works
    to make commercial use of the work

    Under the following conditions:

    Attribution. You must give the original author credit

    Author:  Dean Edwards/2004
    Web:     http://dean.edwards.name/
*/

/* keeping code tidy! */

/* extendible css query function for common platforms

   tested on IE5.0/5.5/6.0, Mozilla 1.6/Firefox 0.8, Opera 7.23/7.5
   (all windows platforms - somebody buy me a mac!)
*/

// -----------------------------------------------------------------------
//  css query engine
// -----------------------------------------------------------------------

var cssQuery = function() {
    var version = "1.0.1"; // timestamp: 2004/05/25

    // constants
    var STANDARD_SELECT = /^[^>\+~\s]/;
    var STREAM = /[\s>\+~:@#\.]|[^\s>\+~:@#\.]+/g;
    var NAMESPACE = /\|/;
    var IMPLIED_SELECTOR = /([\s>\+~\,]|^)([\.:#@])/g;
    var ASTERISK ="$1*$2";
    var WHITESPACE = /^\s+|\s*([\+\,>\s;:])\s*|\s+$/g;
    var TRIM = "$1";
    var NODE_ELEMENT = 1;
    var NODE_TEXT = 3;
    var NODE_DOCUMENT = 9;

    // sniff for explorer (cos of one little bug)
    var isMSIE = /MSIE/.test(navigator.appVersion), isXML;

    // cache results for faster processing
    var cssCache = {};

    // this is the query function
    function cssQuery(selector, from) {
        if (!selector) return [];
        var useCache = arguments.callee.caching && !from;
        from = (from) ? (from.constructor == Array) ? from : [from] : [document];
        isXML = checkXML(from[0]);
        // process comma separated selectors
        var selectors = parseSelector(selector).split(",");
        var match = [];
        for (var i in selectors) {
            // convert the selector to a stream
            selector = toStream(selectors[i]);
            // process the stream
            var j = 0, token, filter, cacheSelector = "", filtered = from;
            while (j < selector.length) {
                token = selector[j++];
                filter = selector[j++];
                cacheSelector += token + filter;
                // process a token/filter pair
                filtered = (useCache && cssCache[cacheSelector]) ? cssCache[cacheSelector] : select(filtered, token, filter);
                if (useCache) cssCache[cacheSelector] = filtered;
            }
            match = match.concat(filtered);
        }
        // return the filtered selection
        return match;
    };
    cssQuery.caching = false;
    cssQuery.reset = function() {
        cssCache = {};
    };
    cssQuery.toString = function () {
        return "function cssQuery() {\n  [version " + version + "]\n}";
    };

    var checkXML = (isMSIE) ? function(node) {
        if (node.nodeType != NODE_DOCUMENT) node = node.document;
        return node.mimeType == "XML Document";
    } : function(node) {
        if (node.nodeType == NODE_DOCUMENT) node = node.documentElement;
        return node.localName != "HTML";
    };

    function parseSelector(selector) {
        return selector
        // trim whitespace
        .replace(WHITESPACE, TRIM)
        // encode attribute selectors
        .replace(attributeSelector.ALL, attributeSelector.ID)
        // e.g. ".class1" --> "*.class1"
        .replace(IMPLIED_SELECTOR, ASTERISK);
    };

    // convert css selectors to a stream of tokens and filters
    //  it's not a real stream. it's just an array of strings.
    function toStream(selector) {
        if (STANDARD_SELECT.test(selector)) selector = " " + selector;
        return selector.match(STREAM) || [];
    };

    var pseudoClasses = { // static
        // CSS1
        "link": function(element) {
            for (var i = 0; i < document.links; i++) {
                if (document.links[i] == element) return true;
            }
        },
        "visited": function(element) {
            // can't do this without jiggery-pokery
        },
        // CSS2
        "first-child": function(element) {
            return !previousElement(element);
        },
        // CSS3
        "last-child": function(element) {
            return !nextElement(element);
        },
        "root": function(element) {
            var document = element.ownerDocument || element.document;
            return Boolean(element == document.documentElement);
        },
        "empty": function(element) {
            for (var i = 0; i < element.childNodes.length; i++) {
                if (isElement(element.childNodes[i]) || element.childNodes[i].nodeType == NODE_TEXT) return false;
            }
            return true;
        }
        // add your own...
    };

    var QUOTED = /([\'\"])[^\1]*\1/;
    function quote(value) {return (QUOTED.test(value)) ? value : "'" + value + "'"};
    function unquote(value) {return (QUOTED.test(value)) ? value.slice(1, -1) : value};

    var attributeSelectors = [];

    function attributeSelector(attribute, compare, value) {
        // properties
        this.id = attributeSelectors.length;
        // build the test expression
        var test = "element.";
        switch (attribute.toLowerCase()) {
            case "id":
                test += "id";
                break;
            case "class":
                test += "className";
                break;
            default:
                test += "getAttribute('" + attribute + "')";
        }
        // continue building the test expression
        switch (compare) {
            case "=":
                test += "==" + quote(value);
                break;
            case "~=":
                test = "/(^|\\s)" + unquote(value) + "(\\s|$)/.test(" + test + ")";
                break;
            case "|=":
                test = "/(^|-)" + unquote(value) + "(-|$)/.test(" + test + ")";
                break;
        }
        push(attributeSelectors, new Function("element", "return " + test));
    };
    attributeSelector.prototype.toString = function() {
        return attributeSelector.PREFIX + this.id;
    };
    // constants
    attributeSelector.PREFIX = "@";
    attributeSelector.ALL = /\[([^~|=\]]+)([~|]?=?)([^\]]+)?\]/g;
    // class methods
    attributeSelector.ID = function(match, attribute, compare, value) {
        return new attributeSelector(attribute, compare, value);
    };

    // select a set of matching elements.
    // "from" is an array of elements.
    // "token" is a character representing the type of filter
    //  e.g. ">" means child selector
    // "filter" represents the tag name, id or class name that is being selected
    // the function returns an array of matching elements
    function select(from, token, filter) {
        //alert("token="+token+",filter="+filter);
        var namespace = "";
        if (NAMESPACE.test(filter)) {
            filter = filter.split("|");
            namespace = filter[0];
            filter = filter[1];
        }
        var filtered = [], i;
        switch (token) {
            case " ": // descendant
                for (i in from) {
                    var subset = getElementsByTagNameNS(from[i], filter, namespace);
                    for (var j = 0; j < subset.length; j++) {
                        if (isElement(subset[j]) && (!namespace || compareNamespace(subset[j], namespace)))
                            push(filtered, subset[j]);
                    }
                }
                break;
            case ">": // child
                for (i in from) {
                    var subset = from[i].childNodes;
                    for (var j = 0; j < subset.length; j++)
                        if (compareTagName(subset[j], filter, namespace)) push(filtered, subset[j]);
                }
                break;
            case "+": // adjacent (direct)
                for (i in from) {
                    var adjacent = nextElement(from[i]);
                    if (adjacent && compareTagName(adjacent, filter, namespace)) push(filtered, adjacent);
                }
                break;
            case "~": // adjacent (indirect)
                for (i in from) {
                    var adjacent = from[i];
                    while (adjacent = nextElement(adjacent)) {
                        if (adjacent && compareTagName(adjacent, filter, namespace)) push(filtered, adjacent);
                    }
                }
                break;
            case ".": // class
                filter = new RegExp("(^|\\s)" + filter + "(\\s|$)");
                for (i in from) if (filter.test(from[i].className)) push(filtered, from[i]);
                break;
            case "#": // id
                for (i in from) if (from[i].id == filter) push(filtered, from[i]);
                break;
            case "@": // attribute selector
                filter = attributeSelectors[filter];
                for (i in from) if (filter(from[i])) push(filtered, from[i]);
                break;
            case ":": // pseudo-class (static)
                filter = pseudoClasses[filter];
                for (i in from) if (filter(from[i])) push(filtered, from[i]);
                break;
        }
        return filtered;
    };

    var getElementsByTagNameNS = (isMSIE) ? function(from, tagName) {
        return (tagName == "*" && from.all) ? from.all : from.getElementsByTagName(tagName);
    } : function(from, tagName, namespace) {
        return (namespace) ? from.getElementsByTagNameNS("*", tagName) : from.getElementsByTagName(tagName);
    };

    function compareTagName(element, tagName, namespace) {
        if (namespace && !compareNamespace(element, namespace)) return false;
        return (tagName == "*") ? isElement(element) : (isXML) ? (element.tagName == tagName) : (element.tagName == tagName.toUpperCase());
    };

    var PREFIX = (isMSIE) ? "scopeName" : "prefix";
    function compareNamespace(element, namespace) {
        return element[PREFIX] == namespace;
    };

    // return the previous element to the supplied element
    //  previousSibling is not good enough as it might return a text or comment node
    function previousElement(element) {
        while ((element = element.previousSibling) && !isElement(element)) continue;
        return element;
    };

    // return the next element to the supplied element
    function nextElement(element) {
        while ((element = element.nextSibling) && !isElement(element)) continue;
        return element;
    };

    function isElement(node) {
        return Boolean(node.nodeType == NODE_ELEMENT && node.tagName != "!");
    };

    // use a baby push function because IE5.0 doesn't support Array.push
    function push(array, item) {
        array[array.length] = item;
    };

    // fix IE5.0 String.replace
    if ("i".replace(/i/,function(){return""})) {
        // preserve String.replace
        var string_replace = String.prototype.replace;
        // create String.replace for handling functions
        var function_replace = function(regexp, replacement) {
            var match, newString = "", string = this;
            while ((match = regexp.exec(string))) {
                // five string replacement arguments is sufficent for cssQuery
                newString += string.slice(0, match.index) + replacement(match[0], match[1], match[2], match[3], match[4]);
                string = string.slice(match.lastIndex);
            }
            return newString + string;
        };
        // replace String.replace
        String.prototype.replace = function (regexp, replacement) {
            this.replace = (typeof replacement == "function") ? function_replace : string_replace;
            return this.replace(regexp, replacement);
        };
    }

    return cssQuery;
}();