//******************************************************************************
// Globals, including constants

var UI_GLOBAL = {
    UI_PREFIX: 'ui'
    , XHTML_DOCTYPE: '<!DOCTYPE html PUBLIC '
        + '"-//W3C//DTD XHTML 1.0 Strict//EN" '
        + '"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">'
    , XHTML_XMLNS: 'http://www.w3.org/1999/xhtml'
};

//*****************************************************************************
// Exceptions

function UIElementException(message)
{
    this.message = message;
    this.name = 'UIElementException';
}

function UIArgumentException(message)
{
    this.message = message;
    this.name = 'UIArgumentException';
}

function PagesetException(message)
{
    this.message = message;
    this.name = 'PagesetException';
}

function UISpecifierException(message)
{
    this.message = message;
    this.name = 'UISpecifierException';
}

function CommandMatcherException(message)
{
    this.message = message;
    this.name = 'CommandMatcherException';
}

//*****************************************************************************
// UI-Element core

/**
 * The UIElement object. This has been crafted along with UIMap to make
 * specifying UI elements using JSON as simple as possible. Object construction
 * will fail if 1) a proper name isn't provided, 2) a faulty args argument is
 * given, or 3) getLocator() returns undefined for a valid permutation of
 * default argument values. See ui-doc.html for the documentation on the
 * builder syntax.
 *
 * @param uiElementShorthand  an object whose contents conform to the
 *                            UI-Element builder syntax.
 *
 * @return  a new UIElement object
 * @throws  UIElementException
 */
function UIElement(uiElementShorthand)
{
    // a shorthand object might look like:
    //
    // {
    //     name: 'topic'
    //     , description: 'sidebar links to topic categories'
    //     , args: [
    //         {
    //             name: 'name'
    //             , description: 'the name of the topic'
    //             , defaultValues: topLevelTopics
    //         }
    //     ]
    //     , getLocator: function(args) {
    //         return this._listXPath +
    //             "/a[text()=" + args.name.quoteForXPath() + "]";
    //     }
    //     , getGenericLocator: function() {
    //         return this._listXPath + '/a';
    //     }
    //     // maintain testcases for getLocator()
    //     , testcase1: {
    //         // defaultValues used if args not specified
    //         args: { name: 'foo' }
    //         , xhtml: '<div id="topiclist">'
    //             + '<ul><li><a expected-result="1">foo</a></li></ul>'
    //             + '</div>'
    //     }
    //     // set a local element variable
    //     , _listXPath: "//div[@id='topiclist']/ul/li"
    // }
    //
    // name cannot be null or an empty string. Enforce the same requirement for
    // the description.
    
    /**
     * Recursively returns all permutations of argument-value pairs, given
     * a list of argument definitions. Each argument definition will have
     * a set of default values to use in generating said pairs. If an argument
     * has no default values defined, it will not be included among the
     * permutations.
     *
     * @param args        a list of UIArguments
     * @param inDocument  the document object to pass to the getDefaultValues()
     *                    method of each argument.
     *
     * @return  a list of associative arrays containing key value pairs
     */
    this.permuteArgs = function(args, inDocument) {
        if (args.length == 0) {
            return [];
        }
        
        var permutations = [];
        var arg = args[0];
        var remainingArgs = args.slice(1);
        var subsequentPermutations = this.permuteArgs(remainingArgs,
            inDocument);
        var defaultValues = arg.getDefaultValues(inDocument);
        
        // skip arguments for which no default values are defined. If the
        // argument is a required one, then no permutations are possible.
        if (defaultValues.length == 0) {
            if (arg.required) {
                return [];
            }
            else {
                return subsequentPermutations;
            }
        }
        
        for (var i = 0; i < defaultValues.length; ++i) {
            var value = defaultValues[i];
            var permutation;
            
            if (subsequentPermutations.length == 0) {
                permutation = {};
                permutation[arg.name] = value + "";
                permutations.push(permutation);
            }
            else {
                for (var j = 0; j < subsequentPermutations.length; ++j) {
                    permutation = clone(subsequentPermutations[j]);
                    permutation[arg.name] = value + "";
                    permutations.push(permutation);
                }
            }
        }
        
        return permutations;
    }
    
    
    
    /**
     * Returns a list of all testcases for this UIElement.
     */
    this.getTestcases = function()
    {
        return this.testcases;
    }
    
    
    
    /**
     * Run all unit tests, stopping at the first failure, if any. Return true
     * if no failures encountered, false otherwise. See the following thread
     * regarding use of getElementById() on XML documents created by parsing
     * text via the DOMParser:
     *
     * http://groups.google.com/group/comp.lang.javascript/browse_thread/thread/2b1b82b3c53a1282/
     */
    this.test = function()
    {
        var parser = new DOMParser();
        var testcases = this.getTestcases();
        testcaseLoop: for (var i = 0; i < testcases.length; ++i) {
            var testcase = testcases[i];
            var xhtml = UI_GLOBAL.XHTML_DOCTYPE + '<html xmlns="'
                + UI_GLOBAL.XHTML_XMLNS + '">' + testcase.xhtml + '</html>';
            var doc = parser.parseFromString(xhtml, "text/xml");
            if (doc.firstChild.nodeName == 'parsererror') {
                safe_alert('Error parsing XHTML in testcase "' + testcase.name
                    + '" for UI element "' + this.name + '": ' + "\n"
                    + doc.firstChild.firstChild.nodeValue);
            }
            
            // we're no longer using the default locators when testing, because
            // args is now required
            var locator = parse_locator(this.getLocator(testcase.args));
            var results;
            
            if (locator.type == 'xpath' || (locator.type == 'implicit' &&
                locator.string.substring(0, 2) == '//')) {
                // try using the javascript xpath engine to avoid namespace
                // issues. The xpath does have to be lowercase however, it
                // seems. 
                results = eval_xpath(locator.string, doc,
                    { allowNativeXpath: false, returnOnFirstMatch: true });
            }
            else {
                // piece the locator back together
                locator = (locator.type == 'implicit')
                    ? locator.string
                    : locator.type + '=' + locator.string;
                results = eval_locator(locator, doc);
            }
            
            if (results.length && results[0].hasAttribute('expected-result')) {
                continue testcaseLoop;
            }
            
            // testcase failed
            if (is_IDE()) {
                var msg = 'Testcase "' + testcase.name
                    + '" failed for UI element "' + this.name + '":';
                if (!results.length) {
                    msg += '\n"' + (locator.string || locator) + '" did not match any elements!';
                }
                else {
                    msg += '\n' + results[0] + ' was not the expected result!';
                }
                safe_alert(msg);
            }
            return false;
        }
        return true;
    };
    
    
    
    /**
     * Creates a set of locators using permutations of default values for
     * arguments used in the locator construction. The set is returned as an
     * object mapping locators to key-value arguments objects containing the
     * values passed to getLocator() to create the locator.
     *
     * @param opt_inDocument (optional) the document object of the "current"
     *                       page when this method is invoked. Some arguments
     *                       may have default value lists that are calculated
     *                       based on the contents of the page.
     *
     * @return  a list of locator strings
     * @throws  UIElementException
     */
    this.getDefaultLocators = function(opt_inDocument) {
        var defaultLocators = {};
        if (this.args.length == 0) {
            defaultLocators[this.getLocator({})] = {};
        }
        else {
            var permutations = this.permuteArgs(this.args, opt_inDocument);
            if (permutations.length != 0) {
                for (var i = 0; i < permutations.length; ++i) {
                    var args = permutations[i];
                    var locator = this.getLocator(args);
                    if (!locator) {
                        throw new UIElementException('Error in UIElement(): '
                            + 'no getLocator return value for element "' + name
                            + '"');
                    }
                    defaultLocators[locator] = args;
                }
            }
            else {
                // try using no arguments. Parse the locator to make sure it's
                // really good. If it doesn't work, fine.
                try {
                    var locator = this.getLocator();
                    parse_locator(locator);
                    defaultLocators[locator] = {};
                }
                catch (e) {
                    safe_log('debug', e.message);
                }
            }
        }
        return defaultLocators;
    };
    
    
    
    /**
     * Validate the structure of the shorthand notation this object is being
     * initialized with. Throws an exception if there's a validation error.
     *
     * @param uiElementShorthand
     *
     * @throws  UIElementException
     */
    this.validate = function(uiElementShorthand)
    {
        var msg = "UIElement validation error:\n" + print_r(uiElementShorthand);
        if (!uiElementShorthand.name) {
            throw new UIElementException(msg + 'no name specified!');
        }
        if (!uiElementShorthand.description) {
            throw new UIElementException(msg + 'no description specified!');
        }
        if (!uiElementShorthand.locator
            && !uiElementShorthand.getLocator
            && !uiElementShorthand.xpath
            && !uiElementShorthand.getXPath) {
            throw new UIElementException(msg + 'no locator specified!');
        }
    };
    
    
    
    this.init = function(uiElementShorthand)
    {
        this.validate(uiElementShorthand);
        
        this.name = uiElementShorthand.name;
        this.description = uiElementShorthand.description;
        
        // construct a new getLocator() method based on the locator property,
        // or use the provided function. We're deprecating the xpath property
        // and getXPath() function, but still allow for them for backwards
        // compatability.
        if (uiElementShorthand.locator) {
            this.getLocator = function(args) {
                return uiElementShorthand.locator;
            };
        }
        else if (uiElementShorthand.getLocator) {
            this.getLocator = uiElementShorthand.getLocator;
        }
        else if (uiElementShorthand.xpath) {
            this.getLocator = function(args) {
                return uiElementShorthand.xpath;
            };
        }
        else {
            this.getLocator = uiElementShorthand.getXPath;
        }
        
        if (uiElementShorthand.genericLocator) {
            this.getGenericLocator = function() {
                return uiElementShorthand.genericLocator;
            };
        }
        else if (uiElementShorthand.getGenericLocator) {
            this.getGenericLocator = uiElementShorthand.getGenericLocator;
        }
        
        if (uiElementShorthand.getOffsetLocator) {
            this.getOffsetLocator = uiElementShorthand.getOffsetLocator;
        }
        
        // get the testcases and local variables
        this.testcases = [];
        var localVars = {};
        for (var attr in uiElementShorthand) {
            if (attr.match(/^testcase/)) {
                var testcase = uiElementShorthand[attr];
                if (uiElementShorthand.args &&
                    uiElementShorthand.args.length && !testcase.args) {
                    safe_alert('No args defined in ' + attr + ' for UI element '
                        + this.name + '! Skipping testcase.');
                    continue;
                } 
                testcase.name = attr;
                this.testcases.push(testcase);
            }
            else if (attr.match(/^_/)) {
                this[attr] = uiElementShorthand[attr];
                localVars[attr] = uiElementShorthand[attr];
            }
        }
        
        // create the arguments
        this.args = []
        this.argsOrder = [];
        if (uiElementShorthand.args) {
            for (var i = 0; i < uiElementShorthand.args.length; ++i) {
                var arg = new UIArgument(uiElementShorthand.args[i], localVars);
                this.args.push(arg);
                this.argsOrder.push(arg.name);

                // if an exception is thrown when invoking getDefaultValues()
                // with no parameters passed in, assume the method requires an
                // inDocument parameter, and thus may only be invoked at run
                // time. Mark the UI element object accordingly.
                try {
                    arg.getDefaultValues();
                }
                catch (e) {
                    this.isDefaultLocatorConstructionDeferred = true;
                }
            }
            
        }
        
        if (!this.isDefaultLocatorConstructionDeferred) {
            this.defaultLocators = this.getDefaultLocators();
        }
    };
    
    
    
    this.init(uiElementShorthand);
}

// hang this off the UIElement "namespace". This is a composite strategy.
UIElement.defaultOffsetLocatorStrategy = function(locatedElement, pageElement) {
    var strategies = [
        UIElement.linkXPathOffsetLocatorStrategy
        , UIElement.preferredAttributeXPathOffsetLocatorStrategy
        , UIElement.simpleXPathOffsetLocatorStrategy
    ];
    
    for (var i = 0; i < strategies.length; ++i) {
        var strategy = strategies[i];
        var offsetLocator = strategy(locatedElement, pageElement);
        
        if (offsetLocator) {
            return offsetLocator;
        }
    }
    
    return null;
};

UIElement.simpleXPathOffsetLocatorStrategy = function(locatedElement,
    pageElement)
{
    if (is_ancestor(locatedElement, pageElement)) {
        var xpath = "";
        var recorder = Recorder.get(locatedElement.ownerDocument.defaultView);
        var locatorBuilders = recorder.locatorBuilders;
        var currentNode = pageElement;
        
        while (currentNode != null && currentNode != locatedElement) {
            xpath = locatorBuilders.relativeXPathFromParent(currentNode)
                + xpath;
            currentNode = currentNode.parentNode;
        }
        
        var results = eval_xpath(xpath, locatedElement.ownerDocument,
            { contextNode: locatedElement });
        
        if (results.length > 0 && results[0] == pageElement) {
            return xpath;
        }
    }
    
    return null;
};

UIElement.linkXPathOffsetLocatorStrategy = function(locatedElement, pageElement)
{
    if (pageElement.nodeName == 'A' && is_ancestor(locatedElement, pageElement))
    {
        var text = pageElement.textContent
            .replace(/^\s+/, "")
            .replace(/\s+$/, "");
        
        if (text) {
            var xpath = '/descendant::a[normalize-space()='
                + text.quoteForXPath() + ']';
            
            var results = eval_xpath(xpath, locatedElement.ownerDocument,
                { contextNode: locatedElement });
            
            if (results.length > 0 && results[0] == pageElement) {
                return xpath;
            }
        }
    }
    
    return null;
};

// compare to the "xpath:attributes" locator strategy defined in the IDE source
UIElement.preferredAttributeXPathOffsetLocatorStrategy =
    function(locatedElement, pageElement)
{
    // this is an ordered listing of single attributes
    var preferredAttributes =  [
        'name'
        , 'value'
        , 'type'
        , 'action'
        , 'alt'
        , 'title'
        , 'class'
        , 'src'
        , 'href'
        , 'onclick'
    ];
    
    if (is_ancestor(locatedElement, pageElement)) {
        var xpathBase = '/descendant::' + pageElement.nodeName.toLowerCase();
        
        for (var i = 0; i < preferredAttributes.length; ++i) {
            var name = preferredAttributes[i];
            var value = pageElement.getAttribute(name);
            
            if (value) {
                var xpath = xpathBase + '[@' + name + '='
                    + value.quoteForXPath() + ']';
                    
                var results = eval_xpath(xpath, locatedElement.ownerDocument,
                    { contextNode: locatedElement });
                
                if (results.length > 0 && results[0] == pageElement) {
                    return xpath;
                }
            }
        }
    }
    
    return null;
};



/**
 * Constructs a UIArgument. This is mostly for checking that the values are
 * valid.
 *
 * @param uiArgumentShorthand
 * @param localVars
 *
 * @throws  UIArgumentException
 */
function UIArgument(uiArgumentShorthand, localVars)
{
    /**
     * @param uiArgumentShorthand
     *
     * @throws  UIArgumentException
     */
    this.validate = function(uiArgumentShorthand)
    {
        var msg = "UIArgument validation error:\n"
            + print_r(uiArgumentShorthand);
        
        // try really hard to throw an exception!
        if (!uiArgumentShorthand.name) {
            throw new UIArgumentException(msg + 'no name specified!');
        }
        if (!uiArgumentShorthand.description) {
            throw new UIArgumentException(msg + 'no description specified!');
        }
        if (!uiArgumentShorthand.defaultValues &&
            !uiArgumentShorthand.getDefaultValues) {
            throw new UIArgumentException(msg + 'no default values specified!');
        }
    };
    
    
    
    /**
     * @param uiArgumentShorthand
     * @param localVars            a list of local variables
     */
    this.init = function(uiArgumentShorthand, localVars)
    {
        this.validate(uiArgumentShorthand);
        
        this.name = uiArgumentShorthand.name;
        this.description = uiArgumentShorthand.description;
        this.required = uiArgumentShorthand.required || false;
        
        if (uiArgumentShorthand.defaultValues) {
            var defaultValues = uiArgumentShorthand.defaultValues;
            this.getDefaultValues =
                function() { return defaultValues; }
        }
        else {
            this.getDefaultValues = uiArgumentShorthand.getDefaultValues;
        }
        
        for (var name in localVars) {
            this[name] = localVars[name];
        }
    }
    
    
    
    this.init(uiArgumentShorthand, localVars);
}



/**
 * The UISpecifier constructor is overloaded. If less than three arguments are
 * provided, the first argument will be considered a UI specifier string, and
 * will be split out accordingly. Otherwise, the first argument will be
 * considered the path.
 *
 * @param uiSpecifierStringOrPagesetName  a UI specifier string, or the pageset
 *                                        name of the UI specifier
 * @param elementName  the name of the element
 * @param args         an object associating keys to values
 *
 * @return  new UISpecifier object
 */
function UISpecifier(uiSpecifierStringOrPagesetName, elementName, args)
{
    /**
     * Initializes this object from a UI specifier string of the form:
     *
     *     pagesetName::elementName(arg1=value1, arg2=value2, ...)
     *
     * into its component parts, and returns them as an object.
     *
     * @return  an object containing the components of the UI specifier
     * @throws  UISpecifierException
     */
    this._initFromUISpecifierString = function(uiSpecifierString) {
        var matches = /^(.*)::([^\(]+)\((.*)\)$/.exec(uiSpecifierString);
        if (matches == null) {
            throw new UISpecifierException('Error in '
                + 'UISpecifier._initFromUISpecifierString(): "'
                + this.string + '" is not a valid UI specifier string');
        }
        this.pagesetName = matches[1];
        this.elementName = matches[2];
        this.args = (matches[3]) ? parse_kwargs(matches[3]) : {};
    };
    
    
    
    /**
     * Override the toString() method to return the UI specifier string when
     * evaluated in a string context. Combines the UI specifier components into
     * a canonical UI specifier string and returns it.
     *
     * @return   a UI specifier string
     */
    this.toString = function() {
        // empty string is acceptable for the path, but it must be defined
        if (this.pagesetName == undefined) {
            throw new UISpecifierException('Error in UISpecifier.toString(): "'
                + this.pagesetName + '" is not a valid UI specifier pageset '
                + 'name');
        }
        if (!this.elementName) {
            throw new UISpecifierException('Error in UISpecifier.unparse(): "'
                + this.elementName + '" is not a valid UI specifier element '
                + 'name');
        }
        if (!this.args) {
            throw new UISpecifierException('Error in UISpecifier.unparse(): "'
                + this.args + '" are not valid UI specifier args');
        }
        
        uiElement = UIMap.getInstance()
            .getUIElement(this.pagesetName, this.elementName);
        if (uiElement != null) {
            var kwargs = to_kwargs(this.args, uiElement.argsOrder);
        }
        else {
            // probably under unit test
            var kwargs = to_kwargs(this.args);
        }
        
        return this.pagesetName + '::' + this.elementName + '(' + kwargs + ')';
    };
    
    // construct the object
    if (arguments.length < 2) {
        this._initFromUISpecifierString(uiSpecifierStringOrPagesetName);
    }
    else {
        this.pagesetName = uiSpecifierStringOrPagesetName;
        this.elementName = elementName;
        this.args = (args) ? clone(args) : {};
    }
}



function Pageset(pagesetShorthand)
{
    /**
     * Returns true if the page is included in this pageset, false otherwise.
     * The page is specified by a document object.
     *
     * @param inDocument  the document object representing the page
     */
    this.contains = function(inDocument)
    {
        var urlParts = parseUri(unescape(inDocument.location.href));
        var path = urlParts.path
            .replace(/^\//, "")
            .replace(/\/$/, "");
        if (!this.pathRegexp.test(path)) {
            return false;
        }
        for (var paramName in this.paramRegexps) {
            var paramRegexp = this.paramRegexps[paramName];
            if (!paramRegexp.test(urlParts.queryKey[paramName])) {
                return false;
            }
        }
        if (!this.pageContent(inDocument)) {
            return false;
        }
        
        return true;
    }
    
    
    
    this.getUIElements = function()
    {
        var uiElements = [];
        for (var uiElementName in this.uiElements) {
            uiElements.push(this.uiElements[uiElementName]);
        }
        return uiElements;
    };
    
    
    
    /**
     * Returns a list of UI specifier string stubs representing all UI elements
     * for this pageset. Stubs contain all required arguments, but leave
     * argument values blank. Each element stub is paired with the element's
     * description.
     *
     * @return  a list of UI specifier string stubs
     */
    this.getUISpecifierStringStubs = function()
    {
        var stubs = [];
        for (var name in this.uiElements) {
            var uiElement = this.uiElements[name];
            var args = {};
            for (var i = 0; i < uiElement.args.length; ++i) {
                args[uiElement.args[i].name] = '';
            }
            var uiSpecifier = new UISpecifier(this.name, uiElement.name, args);
            stubs.push([
                UI_GLOBAL.UI_PREFIX + '=' + uiSpecifier.toString()
                , uiElement.description
            ]);
        }
        return stubs;
    }
    
    
    
    /**
     * Throws an exception on validation failure.
     */
    this._validate = function(pagesetShorthand)
    {
        var msg = "Pageset validation error:\n"
            + print_r(pagesetShorthand);
        if (!pagesetShorthand.name) {
            throw new PagesetException(msg + 'no name specified!');
        }
        if (!pagesetShorthand.description) {
            throw new PagesetException(msg + 'no description specified!');
        }
        if (!pagesetShorthand.paths &&
            !pagesetShorthand.pathRegexp &&
            !pagesetShorthand.pageContent) {
            throw new PagesetException(msg
                + 'no path, pathRegexp, or pageContent specified!');
        }
    };
    
    
    
    this.init = function(pagesetShorthand)
    {
        this._validate(pagesetShorthand);
        
        this.name = pagesetShorthand.name;
        this.description = pagesetShorthand.description;
        
        var pathPrefixRegexp = pagesetShorthand.pathPrefix
            ? RegExp.escape(pagesetShorthand.pathPrefix) : "";
        var pathRegexp = '^' + pathPrefixRegexp;
        
        if (pagesetShorthand.paths != undefined) {
            pathRegexp += '(?:';
            for (var i = 0; i < pagesetShorthand.paths.length; ++i) {
                if (i > 0) {
                    pathRegexp += '|';
                }
                pathRegexp += RegExp.escape(pagesetShorthand.paths[i]);
            }
            pathRegexp += ')$';
        }
        else if (pagesetShorthand.pathRegexp) {
            pathRegexp += '(?:' + pagesetShorthand.pathRegexp + ')$';
        }

        this.pathRegexp = new RegExp(pathRegexp);
        this.paramRegexps = {};
        for (var paramName in pagesetShorthand.paramRegexps) {
            this.paramRegexps[paramName] =
                new RegExp(pagesetShorthand.paramRegexps[paramName]);
        }
        this.pageContent = pagesetShorthand.pageContent ||
            function() { return true; };
        this.uiElements = {};
    };
    
    
    
    this.init(pagesetShorthand);
}



/**
 * Construct the UI map object, and return it. Once the object is instantiated,
 * it binds to a global variable and will not leave scope.
 *
 * @return  new UIMap object
 */
function UIMap()
{
    // the singleton pattern, split into two parts so that "new" can still
    // be used, in addition to "getInstance()"
    UIMap.self = this;
    
    // need to attach variables directly to the Editor object in order for them
    // to be in scope for Editor methods
    if (is_IDE()) {
        Editor.uiMap = this;
        Editor.UI_PREFIX = UI_GLOBAL.UI_PREFIX;
    }
    
    this.pagesets = new Object();
    
    
    
    /**
     * pageset[pagesetName]
     *   regexp
     *   elements[elementName]
     *     UIElement
     */
    this.addPageset = function(pagesetShorthand)
    {
        try {
            var pageset = new Pageset(pagesetShorthand);
        }
        catch (e) {
            safe_alert("Could not create pageset from shorthand:\n"
                + print_r(pagesetShorthand) + "\n" + e.message);
            return false;
        }
        
        if (this.pagesets[pageset.name]) {
            safe_alert('Could not add pageset "' + pageset.name
                + '": a pageset with that name already exists!');
            return false;
        }
        
        this.pagesets[pageset.name] = pageset;
        return true;
    };
    
    
    
    /**
     * @param pagesetName
     * @param uiElementShorthand  a representation of a UIElement object in
     *                            shorthand JSON.
     */
    this.addElement = function(pagesetName, uiElementShorthand)
    {
        try {
            var uiElement = new UIElement(uiElementShorthand);
        }
        catch (e) {
            safe_alert("Could not create UI element from shorthand:\n"
                + print_r(uiElementShorthand) + "\n" + e.message);
            return false;
        }
        
        // run the element's unit tests only for the IDE, and only when the
        // IDE is starting. Make a rough guess as to the latter condition.
        if (is_IDE() && !editor.selDebugger && !uiElement.test()) {
            safe_alert('Could not add UI element "' + uiElement.name
                + '": failed testcases!');
            return false;
        }
        
        try {
            this.pagesets[pagesetName].uiElements[uiElement.name] = uiElement;
        }
        catch (e) {
            safe_alert("Could not add UI element '" + uiElement.name
                + "' to pageset '" + pagesetName + "':\n" + e.message);
            return false;
        }
        
        return true;
    };
    
    
    
    /**
     * Returns the pageset for a given UI specifier string.
     *
     * @param uiSpecifierString
     * @return  a pageset object
     */
    this.getPageset = function(uiSpecifierString)
    {
        try {
            var uiSpecifier = new UISpecifier(uiSpecifierString);
            return this.pagesets[uiSpecifier.pagesetName];
        }
        catch (e) {
            return null;
        }
    }
    
    
    
    /**
     * Returns the UIElement that a UISpecifierString or pageset and element
     * pair refer to.
     *
     * @param pagesetNameOrUISpecifierString
     * @return  a UIElement, or null if none is found associated with
     *          uiSpecifierString
     */
    this.getUIElement = function(pagesetNameOrUISpecifierString, uiElementName)
    {
        var pagesetName = pagesetNameOrUISpecifierString;
        if (arguments.length == 1) {
            var uiSpecifierString = pagesetNameOrUISpecifierString;
            try {
                var uiSpecifier = new UISpecifier(uiSpecifierString);
                pagesetName = uiSpecifier.pagesetName;
                var uiElementName = uiSpecifier.elementName;
            }
            catch (e) {
                return null;
            }
        }
        try {
            return this.pagesets[pagesetName].uiElements[uiElementName];
        }
        catch (e) {
            return null;
        }
    };
    
    
    
    /**
     * Returns a list of pagesets that "contains" the provided page,
     * represented as a document object. Containership is defined by the
     * Pageset object's contain() method.
     *
     * @param inDocument  the page to get pagesets for
     * @return            a list of pagesets
     */
    this.getPagesetsForPage = function(inDocument)
    {
        var pagesets = [];
        for (var pagesetName in this.pagesets) {
            var pageset = this.pagesets[pagesetName];
            if (pageset.contains(inDocument)) {
                pagesets.push(pageset);
            }
        }
        return pagesets;
    };
    
    
    
    /**
     * Returns a list of all pagesets.
     *
     * @return  a list of pagesets
     */
    this.getPagesets = function()
    {
        var pagesets = [];
        for (var pagesetName in this.pagesets) {
            pagesets.push(this.pagesets[pagesetName]);
        }
        return pagesets;
    };
    
    
    
    /**
     * Returns a list of elements on a page that a given UI specifier string,
     * maps to. If no elements are mapped to, returns an empty list..
     *
     * @param   uiSpecifierString  a String that specifies a UI element with
     *                             attendant argument values
     * @param   inDocument         the document object the specified UI element
     *                             appears in
     * @return                     a potentially-empty list of elements
     *                             specified by uiSpecifierString
     */
    this.getPageElements = function(uiSpecifierString, inDocument)
    {
        var locator = this.getLocator(uiSpecifierString);
        var results = locator ? eval_locator(locator, inDocument) : [];
        return results;
    };
    
    
    
    /**
     * Returns the locator string that a given UI specifier string maps to, or
     * null if it cannot be mapped.
     *
     * @param uiSpecifierString
     */
    this.getLocator = function(uiSpecifierString)
    {
        try {
            var uiSpecifier = new UISpecifier(uiSpecifierString);
        }
        catch (e) {
            safe_alert('Could not create UISpecifier for string "'
                + uiSpecifierString + '": ' + e.message);
            return null;
        }
        
        var uiElement = this.getUIElement(uiSpecifier.pagesetName,
            uiSpecifier.elementName);
        try {
            return uiElement.getLocator(uiSpecifier.args);
        }
        catch (e) {
            return null;
        }
    }
    
    
    
    /**
     * Finds and returns a UI specifier string given an element and the page
     * that it appears on.
     *
     * @param pageElement  the document element to map to a UI specifier
     * @param inDocument   the document the element appears in
     * @return             a UI specifier string, or false if one cannot be
     *                     constructed
     */
    this.getUISpecifierString = function(pageElement, inDocument)
    {
        var is_fuzzy_match =
            BrowserBot.prototype.locateElementByUIElement.is_fuzzy_match;
        var pagesets = this.getPagesetsForPage(inDocument);
        
        for (var i = 0; i < pagesets.length; ++i) {
            var pageset = pagesets[i];
            var uiElements = pageset.getUIElements();
            
            for (var j = 0; j < uiElements.length; ++j) {
                var uiElement = uiElements[j];
                
                // first test against the generic locator, if there is one.
                // This should net some performance benefit when recording on
                // more complicated pages.
                if (uiElement.getGenericLocator) {
                    var passedTest = false;
                    var results =
                        eval_locator(uiElement.getGenericLocator(), inDocument);
                    for (var i = 0; i < results.length; ++i) {
                        if (results[i] == pageElement) {
                            passedTest = true;
                            break;
                        }
                    }
                    if (!passedTest) {
                        continue;
                    }
                }
                
                var defaultLocators;
                if (uiElement.isDefaultLocatorConstructionDeferred) {
                    defaultLocators = uiElement.getDefaultLocators(inDocument);
                }
                else {
                    defaultLocators = uiElement.defaultLocators;
                }
                
                //safe_alert(print_r(uiElement.defaultLocators));
                for (var locator in defaultLocators) {
                    var locatedElements = eval_locator(locator, inDocument);
                    if (locatedElements.length) {
                        var locatedElement = locatedElements[0];
                    }
                    else {
                        continue;
                    }
                    
                    // use a heuristic to determine whether the element
                    // specified is the "same" as the element we're matching
                    if (is_fuzzy_match) {
                        if (is_fuzzy_match(locatedElement, pageElement)) {
                            return UI_GLOBAL.UI_PREFIX + '=' +
                                new UISpecifier(pageset.name, uiElement.name,
                                    defaultLocators[locator]);
                        }
                    }
                    else {
                        if (locatedElement == pageElement) {
                            return UI_GLOBAL.UI_PREFIX + '=' +
                                new UISpecifier(pageset.name, uiElement.name,
                                    defaultLocators[locator]);
                        }
                    }
                    
                    // ok, matching the element failed. See if an offset
                    // locator can complete the match.
                    if (uiElement.getOffsetLocator) {
                        for (var k = 0; k < locatedElements.length; ++k) {
                            var offsetLocator = uiElement
                                .getOffsetLocator(locatedElements[k], pageElement);
                            if (offsetLocator) {
                                return UI_GLOBAL.UI_PREFIX + '=' +
                                    new UISpecifier(pageset.name,
                                        uiElement.name,
                                        defaultLocators[locator])
                                    + '->' + offsetLocator;
                            }
                        }
                    }
                }
            }
        }
        return false;
    };
    
    
    
    /**
     * Returns a sorted list of UI specifier string stubs representing possible
     * UI elements for all pagesets, paired the their descriptions. Stubs
     * contain all required arguments, but leave argument values blank.
     *
     * @return  a list of UI specifier string stubs
     */
    this.getUISpecifierStringStubs = function() {
        var stubs = [];
        var pagesets = this.getPagesets();
        for (var i = 0; i < pagesets.length; ++i) {
            stubs = stubs.concat(pagesets[i].getUISpecifierStringStubs());
        }
        stubs.sort(function(a, b) {
            if (a[0] < b[0]) {
                return -1;
            }
            return a[0] == b[0] ? 0 : 1;
        });
        return stubs;
    }
}

UIMap.getInstance = function() {
    return (UIMap.self == null) ? new UIMap() : UIMap.self;
}

//******************************************************************************
// Rollups

/**
 * The Command object isn't available in the Selenium RC. We introduce an
 * object with the identical constructor. In the IDE, this will be redefined,
 * which is just fine.
 *
 * @param command
 * @param target
 * @param value
 */
if (typeof(Command) == 'undefined') {
    function Command(command, target, value) {
        this.command = command != null ? command : '';
        this.target = target != null ? target : '';
        this.value = value != null ? value : '';
    }
}



/**
 * A CommandMatcher object matches commands during the application of a
 * RollupRule. It's specified with a shorthand format, for example:
 *
 *  new CommandMatcher({
 *      command: 'click'
 *      , target: 'ui=allPages::.+'
 *  })
 *
 * which is intended to match click commands whose target is an element in the
 * allPages PageSet. The matching expressions are given as regular expressions;
 * in the example above, the command must be "click"; "clickAndWait" would be
 * acceptable if 'click.*' were used. Here's a more complete example:
 *
 *  new CommandMatcher({
 *      command: 'type'
 *      , target: 'ui=loginPages::username()'
 *      , value: '.+_test'
 *      , updateArgs: function(command, args) {
 *          args.username = command.value;
 *      }
 *  })
 *
 * Here, the command and target are fixed, but there is variability in the 
 * value of the command. When a command matches, the username is saved to the
 * arguments object.
 */
function CommandMatcher(commandMatcherShorthand)
{
    /**
     * Ensure the shorthand notation used to initialize the CommandMatcher has
     * all required values.
     *
     * @param commandMatcherShorthand  an object containing information about
     *                                 the CommandMatcher
     */
    this.validate = function(commandMatcherShorthand) {
        var msg = "CommandMatcher validation error:\n"
            + print_r(commandMatcherShorthand);
        if (!commandMatcherShorthand.command) {
            throw new CommandMatcherException(msg + 'no command specified!');
        }
        if (!commandMatcherShorthand.target) {
            throw new CommandMatcherException(msg + 'no target specified!');
        }
        if (commandMatcherShorthand.minMatches &&
            commandMatcherShorthand.maxMatches &&
            commandMatcherShorthand.minMatches >
            commandMatcherShorthand.maxMatches) {
            throw new CommandMatcherException(msg + 'minMatches > maxMatches!');
        }
    };

    /**
     * Initialize this object.
     *
     * @param commandMatcherShorthand  an object containing information used to
     *                                 initialize the CommandMatcher
     */
    this.init = function(commandMatcherShorthand) {
        this.validate(commandMatcherShorthand);
        
        this.command = commandMatcherShorthand.command;
        this.target = commandMatcherShorthand.target;
        this.value = commandMatcherShorthand.value || null;
        this.minMatches = commandMatcherShorthand.minMatches || 1;
        this.maxMatches = commandMatcherShorthand.maxMatches || 1;
        this.updateArgs = commandMatcherShorthand.updateArgs ||
            function(command, args) { return args; };
    };
    
    /**
     * Determines whether a given command matches. Updates args by "reference"
     * and returns true if it does; return false otherwise.
     *
     * @param command  the command to attempt to match
     */
    this.isMatch = function(command) {
        var re = new RegExp('^' + this.command + '$');
        if (! re.test(command.command)) {
            return false;
        }
        re = new RegExp('^' + this.target + '$');
        if (! re.test(command.target)) {
            return false;
        }
        if (this.value != null) {
            re = new RegExp('^' + this.value + '$');
            if (! re.test(command.value)) {
                return false;
            }
        }
        
        // okay, the command matches
        return true;
    };
    
    // initialization
    this.init(commandMatcherShorthand);
}



function RollupRuleException(message)
{
    this.message = message;
    this.name = 'RollupRuleException';
}

function RollupRule(rollupRuleShorthand)
{
    /**
     * Ensure the shorthand notation used to initialize the RollupRule has all
     * required values.
     *
     * @param rollupRuleShorthand  an object containing information about the
     *                             RollupRule
     */
    this.validate = function(rollupRuleShorthand) {
        var msg = "RollupRule validation error:\n"
            + print_r(rollupRuleShorthand);
        if (!rollupRuleShorthand.name) {
            throw new RollupRuleException(msg + 'no name specified!');
        }
        if (!rollupRuleShorthand.description) {
            throw new RollupRuleException(msg + 'no description specified!');
        }
        // rollupRuleShorthand.args is optional
        if (!rollupRuleShorthand.commandMatchers &&
            !rollupRuleShorthand.getRollup) {
            throw new RollupRuleException(msg
                + 'no command matchers specified!');
        }
        if (!rollupRuleShorthand.expandedCommands &&
            !rollupRuleShorthand.getExpandedCommands) {
            throw new RollupRuleException(msg
                + 'no expanded commands specified!');
        }
        
        return true;
    };

    /**
     * Initialize this object.
     *
     * @param rollupRuleShorthand  an object containing information used to
     *                             initialize the RollupRule
     */
    this.init = function(rollupRuleShorthand) {
        this.validate(rollupRuleShorthand);
        
        this.name = rollupRuleShorthand.name;
        this.description = rollupRuleShorthand.description;
        this.pre = rollupRuleShorthand.pre || '';
        this.post = rollupRuleShorthand.post || '';
        this.alternateCommand = rollupRuleShorthand.alternateCommand;
        this.args = rollupRuleShorthand.args || [];
        
        if (rollupRuleShorthand.commandMatchers) {
            // construct the rule from the list of CommandMatchers
            this.commandMatchers = [];
            var matchers = rollupRuleShorthand.commandMatchers;
            for (var i = 0; i < matchers.length; ++i) {
                if (matchers[i].updateArgs && this.args.length == 0) {
                    // enforce metadata for arguments
                    var msg = "RollupRule validation error:\n"
                        + print_r(rollupRuleShorthand)
                        + 'no argument metadata provided!';
                    throw new RollupRuleException(msg);
                }
                this.commandMatchers.push(new CommandMatcher(matchers[i]));
            }
            
            // returns false if the rollup doesn't match, or a rollup command
            // if it does. If returned, the command contains the
            // replacementIndexes property, which indicates which commands it
            // substitutes for.
            this.getRollup = function(commands) {
                // this is a greedy matching algorithm
                var replacementIndexes = [];
                var commandMatcherQueue = this.commandMatchers;
                var matchCount = 0;
                var args = {};
                for (var i = 0, j = 0; i < commandMatcherQueue.length;) {
                    var matcher = commandMatcherQueue[i];
                    if (j >= commands.length) {
                        // we've run out of commands! If the remaining matchers
                        // do not have minMatches requirements, this is a
                        // match. Otherwise, it's not.
                        if (matcher.minMatches > 0) {
                            return false;
                        }
                        ++i;
                        matchCount = 0; // unnecessary, but let's be consistent
                    }
                    else {
                        if (matcher.isMatch(commands[j])) {
                            ++matchCount;
                            if (matchCount == matcher.maxMatches) {
                                // exhausted this matcher's matches ... move on
                                // to next matcher
                                ++i;
                                matchCount = 0;
                            }
                            args = matcher.updateArgs(commands[j], args);
                            replacementIndexes.push(j);
                            ++j; // move on to next command
                        }
                        else {
                            //alert(matchCount + ', ' + matcher.minMatches);
                            if (matchCount < matcher.minMatches) {
                                return false;
                            }
                            // didn't match this time, but we've satisfied the
                            // requirements already ... move on to next matcher
                            ++i;
                            matchCount = 0;
                            // still gonna look at same command
                        }
                    }
                }
                
                var rollup;
                if (this.alternateCommand) {
                    rollup = new Command(this.alternateCommand,
                        commands[0].target, commands[0].value);
                }
                else {
                    rollup = new Command('rollup', this.name);
                    rollup.value = to_kwargs(args);
                }
                rollup.replacementIndexes = replacementIndexes;
                return rollup;
            };
        }
        else {
            this.getRollup = function(commands) {
                var result = rollupRuleShorthand.getRollup(commands);
                if (result) {
                    var rollup = new Command(
                        result.command
                        , result.target
                        , result.value
                    );
                    rollup.replacementIndexes = result.replacementIndexes;
                    return rollup;
                }
                return false;
            };
        }
        
        this.getExpandedCommands = function(kwargs) {
            var commands = [];
            var expandedCommands = (rollupRuleShorthand.expandedCommands
                ? rollupRuleShorthand.expandedCommands
                : rollupRuleShorthand.getExpandedCommands(
                    parse_kwargs(kwargs)));
            for (var i = 0; i < expandedCommands.length; ++i) {
                var command = expandedCommands[i];
                commands.push(new Command(
                    command.command
                    , command.target
                    , command.value
                ));
            }
            return commands;
        };
    };
    
    this.init(rollupRuleShorthand);
}



/**
 *
 */
function RollupManager()
{
    // singleton pattern
    RollupManager.self = this;
    
    this.init = function()
    {
        this.rollupRules = {};
        if (is_IDE()) {
            Editor.rollupManager = this;
        }
    };

    /**
     * Adds a new RollupRule to the repository. Returns true on success, or
     * false if the rule couldn't be added.
     *
     * @param rollupRuleShorthand  shorthand JSON specification of the new
     *                             RollupRule, possibly including CommandMatcher
     *                             shorthand too.
     * @return                     true if the rule was added successfully,
     *                             false otherwise.
     */
    this.addRollupRule = function(rollupRuleShorthand)
    {
        try {
            var rule = new RollupRule(rollupRuleShorthand);
            this.rollupRules[rule.name] = rule;
        }
        catch(e) {
            smart_alert("Could not create RollupRule from shorthand:\n\n"
                + e.message);
            return false;
        }
        return true;
    };
    
    /**
     * Returns a RollupRule by name.
     *
     * @param rollupName  the name of the rule to fetch
     * @return            the RollupRule, or null if it isn't found.
     */
    this.getRollupRule = function(rollupName)
    {
        return (this.rollupRules[rollupName] || null);
    };
    
    /**
     * Returns a list of name-description pairs for use in populating the
     * auto-populated target dropdown in the IDE. Rules that have an alternate
     * command defined are not included in the list, as they are not bona-fide
     * rollups.
     *
     * @return  a list of name-description pairs
     */
    this.getRollupRulesForDropdown = function()
    {
        var targets = [];
        var names = keys(this.rollupRules).sort();
        for (var i = 0; i < names.length; ++i) {
            var name = names[i];
            if (this.rollupRules[name].alternateCommand) {
                continue;
            }
            targets.push([ name, this.rollupRules[name].description ]);
        }
        return targets;
    };
    
    /**
     * Applies all rules to the current editor commands, asking the user in
     * each case if it's okay to perform the replacement. The rules are applied
     * repeatedly until there are no more matches. The algorithm should
     * remember when the user has declined a replacement, and not ask to do it
     * again.
     *
     * @return  the list of commands with rollup replacements performed
     */
    this.applyRollupRules = function()
    {
        var commands = editor.getTestCase().commands;
        var blacklistedRollups = {};
    
        // so long as rollups were performed, we need to keep iterating through
        // the commands starting at the beginning, because further rollups may
        // potentially be applied on the newly created ones.
        while (true) {
            var performedRollup = false;
            for (var i = 0; i < commands.length; ++i) {
                // iterate through commands
                for (var rollupName in this.rollupRules) {
                    var rule = this.rollupRules[rollupName];
                    var rollup = rule.getRollup(commands.slice(i));
                    if (rollup) {
                        // since we passed in a sliced version of the commands
                        // array to the getRollup() method, we need to re-add 
                        // the offset to the replacementIndexes
                        var k = 0;
                        for (; k < rollup.replacementIndexes.length; ++k) {
                            rollup.replacementIndexes[k] += i;
                        }
                        
                        // build the confirmation message
                        var msg = "Perform the following command rollup?\n\n";
                        for (k = 0; k < rollup.replacementIndexes.length; ++k) {
                            var replacementIndex = rollup.replacementIndexes[k];
                            var command = commands[replacementIndex];
                            msg += '[' + replacementIndex + ']: ';
                            msg += command + "\n";
                        }
                        msg += "\n";
                        msg += rollup;
                        
                        // check against blacklisted rollups
                        if (blacklistedRollups[msg]) {
                            continue;
                        }
                        
                        // highlight the potentially replaced rows
                        for (k = 0; k < commands.length; ++k) {
                            var command = commands[k];
                            command.result = '';
                            if (rollup.replacementIndexes.indexOf(k) != -1) {
                                command.selectedForReplacement = true;
                            }
                            editor.view.rowUpdated(replacementIndex);
                        }
                        
                        // get confirmation from user
                        if (confirm(msg)) {
                            // perform rollup
                            var deleteRanges = [];
                            var replacementIndexes = rollup.replacementIndexes;
                            for (k = 0; k < replacementIndexes.length; ++k) {
                                // this is expected to be list of ranges. A
                                // range has a start, and a list of commands.
                                // The deletion only checks the length of the
                                // command list.
                                deleteRanges.push({
                                    start: replacementIndexes[k]
                                    , commands: [ 1 ]
                                });
                            }
                            editor.view.executeAction(new TreeView
                                .DeleteCommandAction(editor.view,deleteRanges));
                            editor.view.insertAt(i, rollup);
                            
                            performedRollup = true;
                        }
                        else {
                            // cleverly remember not to try this rollup again
                            blacklistedRollups[msg] = true;
                        }
                        
                        // unhighlight
                        for (k = 0; k < commands.length; ++k) {
                            commands[k].selectedForReplacement = false;
                            editor.view.rowUpdated(k);
                        }
                    }
                }
            }
            if (!performedRollup) {
                break;
            }
        }
        return commands;
    };
    
    this.init();
}

RollupManager.getInstance = function() {
    return (RollupManager.self == null)
        ? new RollupManager()
        : RollupManager.self;
}