MediaWiki:Gadget-checkboxList-core.js

/**
 * Adds support for checkbox lists ([[Template:Checklist]])
 *
 * Examples/Tests: <https://rs.wiki/User:Cqm/Scrapbook_4>
 *
 * History:
 * - 1.0: Original implementation - Cqm
 */

/*
 * DATA STORAGE STRUCTURE
 * ----------------------
 *
 * In its raw, uncompressed format, the stored data is as follows:
 * {
 *     hashedPageName1: [
 *         [0, 1, 0, 1, 0, 1],
 *         [1, 0, 1, 0, 1, 0],
 *         [0, 0, 0, 0, 0, 0]
 *     ],
 *     hashedPageName2: [
 *         [0, 1, 0, 1, 0, 1],
 *         [1, 0, 1, 0, 1, 0],
 *         [0, 0, 0, 0, 0, 0]
 *     ]
 * }
 *
 * Where `hashedPageNameX` is the value of wgPageName passed through our `hashString` function,
 * the arrays of numbers representing tables on a page (from top to bottom) and the numbers
 * representing whether a row is highlighted or not, depending on if it is 1 or 0 respectively.
 *
 * During compression, these numbers are collected into groups of 6 and converted to base64.
 * For example:
 *
 *   1. [0, 1, 0, 1, 0, 1]
 *   2. 0x010101             (1 + 4 + 16 = 21)
 *   3. BASE_64_URL[21]      (U)
 *
 * Once each table's rows have been compressed into strings, they are concatenated using `.` as a
 * delimiter. The hashed page name (which is guaranteed to be 8 characters long) is then prepended
 * to this string to look something like the following:
 *
 *   XXXXXXXXab.dc.ef
 *
 *
 * The first character of a hashed page name is then used to form the object that is actually
 * stored. As the hashing function uses hexadecimal, this gives us 16 possible characters (0-9A-Z).
 *
 * {
 *     A: ...
 *     B: ...
 *     C: ...
 *     // etc.
 * }
 *
 * The final step of compression is to merge each page's data together under it's respective top
 * level key. this is done by concatenation again, separated by a `!`.
 *
 * The resulting object is then converted to a string and persisted in local storage. When
 * uncompressing data, simply perform the following steps in reverse.
 *
 * For the implementation of this algorithm, see:
 * - `compress`
 * - `parse`
 * - `hashString`
 *
 * Note that while rows could theoretically be compressed further by using all ASCII characters,
 * eventually we'd start using characters outside printable ASCII which makes debugging painful.
 */

/*jshint bitwise:false, camelcase:true, curly:true, eqeqeq:true, es3:false,
    forin:true, immed:true, indent:4, latedef:true, newcap:true,
    noarg:true, noempty:true, nonew:true, plusplus:true, quotmark:single,
    undef:true, unused:true, strict:true, trailing:true,
    browser:true, devel:false, jquery:true,
    onevar:true
*/

'use strict';

    // constants
var STORAGE_KEY = 'rs:checkList',
    LIST_CLASS = 'checklist',
    CHECKED_CLASS = 'checked',
    NO_TOGGLE_PARENT_CLASS = 'no-toggle-parent',
    INDEX_ATTRIBUTE = 'data-checklist-index',
    BASE_64_URL = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_',
    PAGE_SEPARATOR = '!',
    LIST_SEPARATOR = '.',
    CASTAGNOLI_POLYNOMIAL = 0x04c11db7,
    UINT32_MAX = 0xffffffff,

    conf = mw.config.get([
        'debug',
        'wgPageName'
    ]),


    self = {
        /*
         * Stores the current uncompressed data for the current page.
         */
        data: null,

        /*
         * Perform initial checks on the page and browser.
         */
        init: function () {
            var $lists = $(['ul.' + LIST_CLASS,
                            'div.' + LIST_CLASS + ' > ul'].join(', ')),
                hashedPageName = self.hashString(mw.config.get('wgPageName'));

            // check we have some tables to interact with
            if (!$lists.length) {
                return;
            }

            // check the browser supports local storage
            if (!rs.hasLocalStorage()) {
                return;
            }

            self.data = self.load(hashedPageName, $lists.length);
            self.initLists(hashedPageName, $lists);
        },

        /*
         * Initialise table highlighting.
         *
         * @param hashedPageName The current page name as a hash.
         * @param $lists A list of checkbox lists on the current page.
         */
        initLists: function (hashedPageName, $lists) {
            $lists.each(function (listIndex) {
                var $this = $(this),
                    toggleParent = !(
                        $this.hasClass(NO_TOGGLE_PARENT_CLASS) ||
                        $this.parent('div.' + LIST_CLASS).hasClass(NO_TOGGLE_PARENT_CLASS)
                    ),
                    // list items
                    $items = $this.find('li'),
                    listData = self.data[listIndex];

                // initialise list items if necessary
                while ($items.length > listData.length) {
                    listData.push(0);
                }

                $items.each(function (itemIndex) {
                    var $this = $(this),
                        itemData = listData[itemIndex];

                    // initialize checking based on the cookie
                    self.setChecked($this, itemData);

                    // give the item a unique index in the list
                    $this.attr(INDEX_ATTRIBUTE, itemIndex);

                    // set mouse events
                    $this
                        .click(function (e) {
                            var $this = $(this),
                                $parent = $this.parent('ul').parent('li'),
                                $childItems = $this.children('ul').children('li'),
                                isChecked;

                            // don't bubble up to parent lists
                            e.stopPropagation();

                            function checkChildItems() {
                                var $this = $(this),
                                    index = $this.attr(INDEX_ATTRIBUTE),
                                    $childItems = $this.children('ul').children('li'),
                                    childIsChecked = $this.hasClass(CHECKED_CLASS);

                                if (
                                    (isChecked && !childIsChecked) ||
                                    (!isChecked && childIsChecked)
                                ) {
                                    listData[index] = 1 - listData[index];
                                    self.setChecked($this, listData[index]);
                                }

                                if ($childItems.length) {
                                    $childItems.each(checkChildItems);
                                }
                            }

                            function checkParent($parent) {
                                var parentIndex = $parent.attr(INDEX_ATTRIBUTE),
                                    parentIsChecked = $parent.hasClass(CHECKED_CLASS),
                                    parentShouldBeChecked = true,
                                    $myParent = $parent.parent('ul').parent('li');

                                $parent.children('ul').children('li').each(function () {
                                    var $child = $(this),
                                        childIsChecked = $child.hasClass(CHECKED_CLASS);

                                    if (!childIsChecked) {
                                        parentShouldBeChecked = false;
                                    }
                                });

                                if (
                                    (parentShouldBeChecked && !parentIsChecked && toggleParent) ||
                                    (!parentShouldBeChecked && parentIsChecked)
                                ) {
                                    listData[parentIndex] = 1 - listData[parentIndex];
                                    self.setChecked($parent, listData[parentIndex]);
                                }

                                if ($myParent.length) {
                                    checkParent($myParent);
                                }
                            }

                            // don't toggle highlight when clicking links
                            if ((e.target.tagName !== 'A') && (e.target.tagName !== 'IMG')) {
                                // 1 -> 0
                                // 0 -> 1
                                listData[itemIndex] = 1 - listData[itemIndex];

                                self.setChecked($this, listData[itemIndex]);
                                isChecked = $this.hasClass(CHECKED_CLASS);

                                if ($childItems.length) {
                                    $childItems.each(checkChildItems);
                                }

                                // if the list has a parent
                                // check if all the children are checked and uncheck the parent if not
                                if ($parent.length) {
                                    checkParent($parent);
                                }

                                self.save(hashedPageName);
                            }
                        });
                });
                
                // add a button for reset
                var reset = $('<div>').append(
                	$('<sup>').append('[').append(
                		$('<a>').append('uncheck all')
            		).append(']')
                ).addClass('sl-reset');

                reset.first('sup').click(function () {
                    $items.each(function (itemIndex) {
                        listData[itemIndex] = 0;
                        self.setChecked($(this), 0);
                    });

                    self.save(hashedPageName, $lists.length);
                });
                
                $this.append(reset);
            });
        },

        /*
         * Change the list item checkbox based on mouse events.
         *
         * @param $item The list item element.
         * @param val The value to control what class to add (if any).
         *            0 -> unchecked (no class)
         *            1 -> light on
         *            2 -> mouse over
         */
        setChecked: function ($item, val) {
            $item.removeClass(CHECKED_CLASS);

            switch (val) {
                // checked
                case 1:
                    $item.addClass(CHECKED_CLASS);
                    break;
            }
        },

        /*
         * Merge the updated data for the current page into the data for other pages into local storage.
         *
         * @param hashedPageName A hash of the current page name.
         */
        save: function (hashedPageName) {
                // load the existing data so we know where to save it
            var curData = localStorage.getItem(STORAGE_KEY),
                compressedData;

            if (curData === null) {
                curData = {};
            } else {
                curData = JSON.parse(curData);
                curData = self.parse(curData);
            }

            // merge in our updated data and compress it
            curData[hashedPageName] = self.data;
            compressedData = self.compress(curData);

            // convert to a string and save to localStorage
            compressedData = JSON.stringify(compressedData);
            localStorage.setItem(STORAGE_KEY, compressedData);
        },

        /*
         * Compress the entire data set using tha algoritm documented at the top of the page.
         *
         * @param data The data to compress.
         *
         * @return the compressed data.
         */
        compress: function (data) {
            var ret = {};
            
            Object.keys(data).forEach(function (hashedPageName) {
                var pageData = data[hashedPageName],
                    pageKey = hashedPageName.charAt(0);

                if (!ret.hasOwnProperty(pageKey)) {
                    ret[pageKey] = {};
                }

                ret[pageKey][hashedPageName] = [];

                pageData.forEach(function (tableData) {
                    var compressedListData = '',
                        i, j, k;

                    for (i = 0; i < Math.ceil(tableData.length / 6); i += 1) {
                        k = tableData[6 * i];

                        for (j = 1; j < 6; j += 1) {
                            k = 2 * k + ((6 * i + j < tableData.length) ? tableData[6 * i + j] : 0);
                        }

                        compressedListData += BASE_64_URL.charAt(k);
                    }

                    ret[pageKey][hashedPageName].push(compressedListData);
                });

                ret[pageKey][hashedPageName] = ret[pageKey][hashedPageName].join(LIST_SEPARATOR);
            });

            Object.keys(ret).forEach(function (pageKey) {
                var hashKeys = Object.keys(ret[pageKey]),
                    hashedData = [];

                hashKeys.forEach(function (key) {
                    var pageData = ret[pageKey][key];
                    hashedData.push(key + pageData);
                });

                hashedData = hashedData.join(PAGE_SEPARATOR);
                ret[pageKey] = hashedData;
            });

            return ret;
        },

        /*
         * Get the existing data for the current page.
         *
         * @param hashedPageName A hash of the current page name.
         * @param numLists The number of lists on the current page. Used to ensure the loaded
         *                 data matches the number of lists on the page thus handling cases
         *                 where lists have been added or removed. This does not check the
         *                 amount of items in the given lists.
         *
         * @return The data for the current page.
         */
        load: function (hashedPageName, numLists) {
            var data = localStorage.getItem(STORAGE_KEY),
                pageData;

            if (data === null) {
                pageData = [];
            } else {
                data = JSON.parse(data);
                data = self.parse(data);

                if (data.hasOwnProperty(hashedPageName)) {
                    pageData = data[hashedPageName];
                } else {
                    pageData = [];
                }
            }

            // if more lists were added
            // add extra arrays to store the data in
            // also populates if no existing data was found
            while (numLists > pageData.length) {
                pageData.push([]);
            }

            // if lists were removed, remove data from the end of the list
            // as there's no way to tell which was removed
            while (numLists < pageData.length) {
                pageData.pop();
            }

            return pageData;
        },

        /*
         * Parse the compressed data as loaded from local storage using the algorithm desribed
         * at the top of the page.
         *
         * @param data The data to parse.
         *
         * @return the parsed data.
         */
        parse: function (data) {
            var ret = {};

            Object.keys(data).forEach(function (pageKey) {
                var pageData = data[pageKey].split(PAGE_SEPARATOR);

                pageData.forEach(function (listData) {
                    var hashedPageName = listData.substr(0, 8);

                    listData = listData.substr(8).split(LIST_SEPARATOR);
                    ret[hashedPageName] = [];

                    listData.forEach(function (itemData, index) {
                        var i, j, k;

                        ret[hashedPageName].push([]);

                        for (i = 0; i < itemData.length; i += 1) {
                            k = BASE_64_URL.indexOf(itemData.charAt(i));

                            // input validation
                            if (k < 0) {
                                k = 0;
                            }

                            for (j = 5; j >= 0; j -= 1) {
                                ret[hashedPageName][index][6 * i + j] = (k & 0x1);
                                k >>= 1;
                            }
                        }
                    });
                });

            });

            return ret;
        },

        /*
         * Hash a string into a big endian 32 bit hex string. Used to hash page names.
         *
         * @param input The string to hash.
         *
         * @return the result of the hash.
         */
        hashString: function (input) {
            var ret = 0,
                table = [],
                i, j, k;

            // guarantee 8-bit chars
            input = window.unescape(window.encodeURI(input));

            // calculate the crc (cyclic redundancy check) for all 8-bit data
            // bit-wise operations discard anything left of bit 31
            for (i = 0; i < 256; i += 1) {
                k = (i << 24);

                for (j = 0; j < 8; j += 1) {
                    k = (k << 1) ^ ((k >>> 31) * CASTAGNOLI_POLYNOMIAL);
                }
                table[i] = k;
            }

            // the actual calculation
            for (i = 0; i < input.length; i += 1) {
                ret = (ret << 8) ^ table[(ret >>> 24) ^ input.charCodeAt(i)];
            }

            // make negative numbers unsigned
            if (ret < 0) {
                ret += UINT32_MAX;
            }

            // 32-bit hex string, padded on the left
            ret = '0000000' + ret.toString(16).toUpperCase();
            ret = ret.substr(ret.length - 8);

            return ret;
        }
    };

// disable for debugging
if (!(['User:Cqm/Scrapbook_4'].indexOf(conf.wgPageName) && conf.debug)) {
    $(self.init);
}

/*
// sample data for testing the algorithm used
var data = {
    // page1
    '0FF47C63': [
        [0, 1, 1, 0, 1, 0],
        [0, 1, 1, 0, 1, 0, 1, 1, 1],
        [0, 0, 0, 0, 1, 1, 0, 0]
    ],
    // page2
    '02B75ABA': [
        [0, 1, 0, 1, 1, 0],
        [1, 1, 1, 0, 1, 0, 1, 1, 0],
        [0, 0, 1, 1, 0, 0, 0, 0]
    ],
    // page3
    '0676470D': [
        [1, 0, 0, 1, 0, 1],
        [1, 0, 0, 1, 0, 1, 0, 0, 0],
        [1, 1, 1, 1, 0, 0, 1, 1]
    ]
};

console.log('input', data);

var compressedData = self.compress(data);
console.log('compressed', compressedData);

var parsedData = self.parse(compressedData);
console.log(parsedData);
*/