excessibility

/**
 * +--------------------------------------------------------------------+
 * | This HTML_CodeSniffer file is Copyright (c)                        |
 * | Squiz Pty Ltd (ABN 77 084 670 600)                                 |
 * +--------------------------------------------------------------------+
 * | IMPORTANT: Your use of this Software is subject to the terms of    |
 * | the Licence provided in the file licence.txt. If you cannot find   |
 * | this file please contact Squiz (www.squiz.com.au) so we may        |
 * | provide you a copy.                                                |
 * +--------------------------------------------------------------------+
 *
 */

_global.HTMLCS = new function()
{
    var _standards    = {};
    var _sniffs       = [];
    var _tags         = {};
    var _standard     = null;
    var _currentSniff = null;

    var _messages     = [];
    var _msgOverrides = {};

    /*
        Message type constants.
    */
    this.ERROR   = 1;
    this.WARNING = 2;
    this.NOTICE  = 3;

    // The current language to use.
    this.lang = 'en';

    /**
     * Loads the specified standard and run the sniffs.
     *
     * @param {String}      standard     The name of the standard to load.
     * @param {String|Node} content      An HTML string or a DOM node object.
     * @param {Function}    callback     The function that will be called when the testing is completed.
     * @param {Function}    failCallback The fail callback which will be called if the standard load has failed.
     * @param {String}      language     The language to use for text output.
     */
    this.process = function(
        standard,
        content,
        callback,
        failCallback,
        language
    ) {
        // Clear previous runs.
        _standards    = {};
        _sniffs       = [];
        _tags         = {};
        _standard     = null;

        if (!content) {
            return false;
        }

        // Set a language to use.
        var languages = Object.keys(_global.translation);
        if (language && languages.indexOf(language) !== -1) {
            this.lang = language;
        }

        if (_standards[_getStandardPath(standard)]) {
            HTMLCS.run(callback, content);
        } else {
            this.loadStandard(standard, function() {
                HTMLCS.run(callback, content);
            }, failCallback);
        }
    };

    /**
     * Gets a translation for a text value.
     *
     * @param {String} text The text to get the translation for.
     *
     * @return {String}
     */
    this.getTranslation = function(text) {
        try {
            return _global.translation[this.lang][text];
        } catch (e) {
            throw new Error('Translation for "' + text + '" does not exist in current language ' + this.lang);
        }
    };

    /**
     * Loads the specified standard and its sniffs.
     *
     * @param {String}   standard The name of the standard to load.
     * @param {Function} callback The function to call once the standard is loaded.
     */
    this.loadStandard = function(standard, callback, failCallback) {
        if (!standard) {
            return false;
        }

        _includeStandard(standard, function() {
            _standard = standard;
            callback.call(this);
        }, failCallback);
    };

    /**
     * Runs the sniffs for the loaded standard.
     *
     * @param {Function}    callback The function to call once all sniffs are completed.
     * @param {String|Node} content  An HTML string or a DOM node object.
     */
    this.run = function(callback, content) {
        var element      = null;
        var loadingFrame = false;
        if (typeof content === 'string') {
            loadingFrame = true;
            var elementFrame = document.createElement('iframe');
            elementFrame.style.display = 'none';
            elementFrame = document.body.insertBefore(elementFrame, null);

            if (elementFrame.contentDocument) {
                element = elementFrame.contentDocument;
            } else if (element.contentWindow) {
                element = elementFrame.contentWindow.document;
            }

            elementFrame.load = function() {
                this.onreadystatechange = null;
                this.onload = null;

                if (HTMLCS.isFullDoc(content) === false) {
                    element = element.getElementsByTagName('body')[0];
                    var div = element.getElementsByTagName('div')[0];
                    if (div && (div.id === '__HTMLCS-source-wrap')) {
                        div.id  = '';
                        element = div;
                    }
                }

                var elements = HTMLCS.util.getAllElements(element);
                elements.unshift(element);
                _run(elements, element, callback);
            };

            // Satisfy IE which doesn't like onload being set dynamically.
            elementFrame.onreadystatechange = function() {
                if (/^(complete|loaded)$/.test(this.readyState) === true) {
                    this.onreadystatechange = null;
                    this.load();
                }
            };

            elementFrame.onload = elementFrame.load;

            if ((HTMLCS.isFullDoc(content) === false) && (content.indexOf('<body') === -1)) {
                element.write('<div id="__HTMLCS-source-wrap">' + content + '</div>');
            } else {
                element.write(content);
            }

            element.close();
        } else {
            element = content;
        }

        if (!element) {
            callback.call(this);
            return;
        }

        callback  = callback || function() {};
        _messages = [];

        // Get all the elements in the parent element.
        // Add the parent element too, which will trigger "_top" element codes.
        var elements = HTMLCS.util.getAllElements(element);
        elements.unshift(element);

        // Run the sniffs.
        if (loadingFrame === false) {
            _run(elements, element, callback);
        }
    };

    /**
     * Returns true if the content passed appears to be from a full document.
     *
     * With string content, we consider a full document as the presence of <html>,
     * or <head> + <body> elements. For an element, only the 'html' element (the
     * document element) is accepted.
     *
     * @param {String|Node} content An HTML string or a DOM node object.
     *
     * @returns {Boolean}
     */
    this.isFullDoc = function(content) {
        var fullDoc = false;
        if (typeof content === 'string') {
            if (content.toLowerCase().indexOf('<html') !== -1) {
                fullDoc = true;
            } else if ((content.toLowerCase().indexOf('<head') !== -1) && (content.toLowerCase().indexOf('<body') !== -1)) {
                fullDoc = true;
            }
        } else {
            // If we are the document, or the document element.
            if ((content.nodeName.toLowerCase() === 'html') || (content.documentElement)) {
                fullDoc = true;
            }
        }

        return fullDoc;
    };

    /**
     * Adds a message.
     *
     * @param {Number}  type    The type of the message.
     * @param {Node}    element The element that the message is related to.
     * @param {String}  msg     The message string.
     * @param {String}  code    Unique code for the message.
     * @param {Object}  [data]  Extra data to store for the message.
     */
    this.addMessage = function(type, element, msg, code, data) {
        code = _getMessageCode(code);

        _messages.push({
            type: type,
            element: element,
            msg: _msgOverrides[code] || msg,
            code: code,
            data: data
        });
    };

    /**
     * Returns all the messages for the last run.
     *
     * Return a copy of the array so the class variable doesn't get modified by
     * future modification (eg. splicing).
     *
     * @returns {Array} Array of message objects.
     */
    this.getMessages = function() {
        return _messages.concat([]);
    };

    /**
     * Runs the sniffs in the loaded standard for the specified element.
     *
     * @param {Node}     element    The element to test.
     * @param {Node}     topElement The top element of the processing.
     * @param {Function} [callback] The function to call once all tests are run.
     */
    var _run = function(elements, topElement, callback) {
        var topMsgs = [];
        while (elements.length > 0) {
            var element = elements.shift();

            if (element === topElement) {
                var tagName = '_top';
            } else {
                var tagName = element.tagName.toLowerCase();
            }

            // First check whether any "top" messages need to be shifted off for this
            // element. If so, dump off into the main messages.
            for (var i = 0; i < topMsgs.length;) {
                if (element === topMsgs[i].element) {
                    _messages.push(topMsgs[i]);
                    topMsgs.splice(i, 1);
                } else {
                    i++;
                }
            }//end for

            if (_tags[tagName] && _tags[tagName].length > 0) {
                _processSniffs(element, _tags[tagName].concat([]), topElement);

                // Save "top" messages, and reset the messages array.
                if (tagName === '_top') {
                    topMsgs   = _messages;
                    _messages = [];
                }
            }
        }//end while

        _messages = _messages.concat(topMsgs);

        // Due to filtering of presentation roles for general sniffing these need to be handled
        // separately. The 1.3.1 sniff needs to run to detect any incorrect usage of the presentation
        // role.
        var presentationElems = topElement.querySelectorAll('[role="presentation"]');
        _currentSniff         = HTMLCS_WCAG2AAA_Sniffs_Principle1_Guideline1_3_1_3_1;
        [].forEach.call(presentationElems, function(element) {
            _currentSniff.testSemanticPresentationRole(element);
        });

        if (callback instanceof Function === true) {
            callback.call(this);
        }
    };

    /**
     * Process the sniffs.
     *
     * @param {Node}     element    The element to test.
     * @param {Array}    sniffs     Array of sniffs.
     * @param {Node}     topElement The top element of the processing.
     * @param {Function} [callback] The function to call once the processing is completed.
     */
    var _processSniffs = function(element, sniffs, topElement, callback) {
        while (sniffs.length > 0) {
            var sniff     = sniffs.shift();
            _currentSniff = sniff;

            if (sniff.useCallback === true) {
                // If the useCallback property is set:
                // - Process the sniff.
                // - Recurse into ourselves with remaining sniffs, with no callback.
                // - Clear out the list of sniffs (so they aren't run again), so the
                //   callback (if not already recursed) can run afterwards.
                sniff.process(element, topElement, function() {
                    _processSniffs(element, sniffs, topElement);
                    sniffs = [];
                });
            } else {
                // Process the sniff.
                sniff.process(element, topElement);
            }
        }//end while

        if (callback instanceof Function === true) {
            callback.call(this);
        }
    };

    /**
     * Includes the specified standard file.
     *
     * @param {String}   standard The name of the standard.
     * @param {Function} callback The function to call once the standard is included.
     * @param {Object}   options  The options for the standard (e.g. exclude sniffs).
     */
    var _includeStandard = function(standard, callback, failCallback, options) {
        if (standard.indexOf('http') !== 0) {
            standard = _getStandardPath(standard);
        }//end id

        // See if the ruleset object is already included (eg. if minified).
        var parts   = standard.split('/');
        var ruleSet = _global['HTMLCS_' + parts[(parts.length - 2)]];
        if (ruleSet) {
            // Already included.
            _registerStandard(standard, callback, failCallback, options);
        } else {
            _includeScript(standard, function() {
                // Script is included now register the standard.
                _registerStandard(standard, callback, failCallback, options);
            }, failCallback);
        }//end if
    };

    /**
     * Registers the specified standard and its sniffs.
     *
     * @param {String}   standard The name of the standard.
     * @param {Function} callback The function to call once the standard is registered.
     * @param {Object}   options  The options for the standard (e.g. exclude sniffs).
     */
    var _registerStandard = function(standard, callback, failCallback, options) {
        // Get the object name.
        var parts = standard.split('/');

        // Get a copy of the ruleset object.
        var oldRuleSet = _global['HTMLCS_' + parts[(parts.length - 2)]];
        var ruleSet    = {};

        for (var x in oldRuleSet) {
            if (oldRuleSet.hasOwnProperty(x) === true) {
                ruleSet[x] = oldRuleSet[x];
            }
        }

        if (!ruleSet) {
            return false;
        }

        _standards[standard] = ruleSet;

        // Process the options.
        if (options) {
            if (options.include && options.include.length > 0) {
                // Included sniffs.
                ruleSet.sniffs = options.include;
            } else if (options.exclude) {
                // Excluded sniffs.
                for (var i = 0; i < options.exclude.length; i++) {
                    var index = ruleSet.sniffs.find(options.exclude[i]);
                    if (index >= 0) {
                        ruleSet.sniffs.splice(index, 1);
                    }
                }
            }
        }//end if

        // Register the sniffs for this standard.
        var sniffs = ruleSet.sniffs.slice(0, ruleSet.sniffs.length);
        _registerSniffs(standard, sniffs, callback, failCallback);
    };

    /**
     * Registers the sniffs for the specified standard.
     *
     * @param {String}   standard The name of the standard.
     * @param {Array}    sniffs   List of sniffs to register.
     * @param {Function} callback The function to call once the sniffs are registered.
     */
    var _registerSniffs = function(standard, sniffs, callback, failCallback) {
        if (sniffs.length === 0) {
            callback.call(this);
            return;
        }

        // Include and register sniffs.
        var sniff = sniffs.shift();
        _loadSniffFile(standard, sniff, function() {
            _registerSniffs(standard, sniffs, callback, failCallback);
        }, failCallback);
    };

    /**
     * Includes the sniff's JS file and registers it.
     *
     * @param {String}        standard The name of the standard.
     * @param {String|Object} sniff    The sniff to register, can be a string or
     *                                 and object specifying another standard.
     * @param {Function}      callback The function to call once the sniff is included and registered.
     */
    var _loadSniffFile = function(standard, sniff, callback, failCallback) {
        if (typeof sniff === 'string') {
            var sniffObj = _getSniff(standard, sniff);
            var cb       = function() {
                _registerSniff(standard, sniff);
                callback.call(this);
            };

            // Already loaded.
            if (sniffObj) {
                cb();
            } else {
                _includeScript(_getSniffPath(standard, sniff), cb, failCallback);
            }
        } else {
            // Including a whole other standard.
            _includeStandard(sniff.standard, function() {
                if (sniff.messages) {
                    // Add message overrides.
                    for (var msg in sniff.messages) {
                        _msgOverrides[msg] = sniff.messages[msg];
                    }
                }

                callback.call(this);
            }, failCallback, {
                exclude: sniff.exclude,
                include: sniff.include
            });
        }
    };

    /**
     * Registers the specified sniff.
     *
     * @param {String} standard The name of the standard.
     * @param {String} sniff    The name of the sniff.
     */
    var _registerSniff = function(standard, sniff) {
        // Get the sniff object.
        var sniffObj = _getSniff(standard, sniff);
        if (!sniffObj) {
            return false;
        }

        // Call the register method of the sniff, it should return an array of tags.
        if (sniffObj.register) {
            var watchedTags = sniffObj.register();

            for (var i = 0; i < watchedTags.length; i++) {
                if (!_tags[watchedTags[i]]) {
                    _tags[watchedTags[i]] = [];
                }

                _tags[watchedTags[i]].push(sniffObj);
            }
        }

        _sniffs.push(sniffObj);
    };

    /**
     * Returns the path to the sniff file.
     *
     * @param {String} standard The name of the standard.
     * @param {String} sniff    The name of the sniff.
     *
     * @returns {String} The path to the JS file of the sniff.
     */
    var _getSniffPath = function(standard, sniff) {
        var parts = standard.split('/');
        parts.pop();
        var path = parts.join('/') + '/Sniffs/' + sniff.replace(/\./g, '/') + '.js';
        return path;
    };

    /**
     * Returns the path to a local standard.
     *
     * @param {String} standard The name of the standard.
     *
     * @returns {String} The path to the local standard.
     */
    var _getStandardPath = function(standard)
    {
        // Get the include path of a local standard.
        var scripts = document.getElementsByTagName('script');
        var path    = null;

        // Loop through all the script tags that exist in the document and find the one
        // that has included this file.
        for (var i = 0; i < scripts.length; i++) {
            if (scripts[i].src) {
                if (scripts[i].src.match(/HTMLCS\.js/)) {
                    // We have found our appropriate <script> tag that includes
                    // this file, we can extract the path.
                    path = scripts[i].src.replace(/HTMLCS\.js/,'');

                    // trim any trailing bits
                    path = path.substring(0, path.indexOf('?'));
                    break;
                }
            }
        }

        return path + 'Standards/' + standard + '/ruleset.js';

    };

    /**
     * Returns the sniff object.
     *
     * @param {String} standard The name of the standard.
     * @param {String} sniff    The name of the sniff.
     *
     * @returns {Object} The sniff object.
     */
    var _getSniff = function(standard, sniff) {
        var name = 'HTMLCS_';
        name    += _standards[standard].name + '_Sniffs_';
        name    += sniff.split('.').join('_');

        if (!_global[name]) {
            return null;
        }

        _global[name]._name = sniff;
        return _global[name];
    };

    /**
     * Returns the full message code.
     *
     * A full message code includes the standard name, the sniff name and the given code.
     *
     * @returns {String} The full message code.
     */
    var _getMessageCode = function(code) {
        code = _standard + '.' + _currentSniff._name + '.' + code;
        return code;
    };

    /**
     * Includes the specified JS file.
     *
     * @param {String}   src      The URL to the JS file.
     * @param {Function} callback The function to call once the script is loaded.
     */
    var _includeScript = function(src, callback, failCallback) {
        var script    = document.createElement('script');
        script.onload = function() {
            script.onload = null;
            script.onreadystatechange = null;
            callback.call(this);
        };

        script.onerror = function() {
            script.onload = null;
            script.onreadystatechange = null;
            if (failCallback) {
                failCallback.call(this);
            }
        };

        script.onreadystatechange = function() {
            if (/^(complete|loaded)$/.test(this.readyState) === true) {
                script.onreadystatechange = null;
                script.onload();
            }
        };

        script.src = src;

        if (document.head) {
            document.head.appendChild(script);
        } else {
            document.getElementsByTagName('head')[0].appendChild(script);
        }
    };
};