// jshint multistr:true

(function (w, d) {
    'use strict';

    var TABLE_NAME = 'hljs-ln',
        LINE_NAME = 'hljs-ln-line',
        CODE_BLOCK_NAME = 'hljs-ln-code',
        NUMBERS_BLOCK_NAME = 'hljs-ln-numbers',
        NUMBER_LINE_NAME = 'hljs-ln-n',
        DATA_ATTR_NAME = 'data-line-number',
        BREAK_LINE_REGEXP = /\r\n|\r|\n/g;

    if (w.hljs) {
        w.hljs.initLineNumbersOnLoad = initLineNumbersOnLoad;
        w.hljs.lineNumbersBlock = lineNumbersBlock;
        w.hljs.lineNumbersValue = lineNumbersValue;

        addStyles();
    } else {
        w.console.error('highlight.js not detected!');
    }

    function isHljsLnCodeDescendant(domElt) {
        var curElt = domElt;
        while (curElt) {
            if (curElt.className && curElt.className.indexOf('hljs-ln-code') !== -1) {
                return true;
            }
            curElt = curElt.parentNode;
        }
        return false;
    }

    function getHljsLnTable(hljsLnDomElt) {
        var curElt = hljsLnDomElt;
        while (curElt.nodeName !== 'TABLE') {
            curElt = curElt.parentNode;
        }
        return curElt;
    }

    // Function to workaround a copy issue with Microsoft Edge.
    // Due to hljs-ln wrapping the lines of code inside a <table> element,
    // itself wrapped inside a <pre> element, window.getSelection().toString()
    // does not contain any line breaks. So we need to get them back using the
    // rendered code in the DOM as reference.
    function edgeGetSelectedCodeLines(selection) {
        // current selected text without line breaks
        var selectionText = selection.toString();

        // get the <td> element wrapping the first line of selected code
        var tdAnchor = selection.anchorNode;
        while (tdAnchor.nodeName !== 'TD') {
            tdAnchor = tdAnchor.parentNode;
        }

        // get the <td> element wrapping the last line of selected code
        var tdFocus = selection.focusNode;
        while (tdFocus.nodeName !== 'TD') {
            tdFocus = tdFocus.parentNode;
        }

        // extract line numbers
        var firstLineNumber = parseInt(tdAnchor.dataset.lineNumber);
        var lastLineNumber = parseInt(tdFocus.dataset.lineNumber);

        // multi-lines copied case
        if (firstLineNumber != lastLineNumber) {

            var firstLineText = tdAnchor.textContent;
            var lastLineText = tdFocus.textContent;

            // if the selection was made backward, swap values
            if (firstLineNumber > lastLineNumber) {
                var tmp = firstLineNumber;
                firstLineNumber = lastLineNumber;
                lastLineNumber = tmp;
                tmp = firstLineText;
                firstLineText = lastLineText;
                lastLineText = tmp;
            }

            // discard not copied characters in first line
            while (selectionText.indexOf(firstLineText) !== 0) {
                firstLineText = firstLineText.slice(1);
            }

            // discard not copied characters in last line
            while (selectionText.lastIndexOf(lastLineText) === -1) {
                lastLineText = lastLineText.slice(0, -1);
            }

            // reconstruct and return the real copied text
            var selectedText = firstLineText;
            var hljsLnTable = getHljsLnTable(tdAnchor);
            for (var i = firstLineNumber + 1 ; i < lastLineNumber ; ++i) {
                var codeLineSel = format('.{0}[{1}="{2}"]', [CODE_BLOCK_NAME, DATA_ATTR_NAME, i]);
                var codeLineElt = hljsLnTable.querySelector(codeLineSel);
                selectedText += '\n' + codeLineElt.textContent;
            }
            selectedText += '\n' + lastLineText;
            return selectedText;
        // single copied line case
        } else {
            return selectionText;
        }
    }

    // ensure consistent code copy/paste behavior across all browsers
    document.addEventListener('copy', function(e) {
        // get current selection
        var selection = window.getSelection();
        // override behavior when one wants to copy line of codes
        if (isHljsLnCodeDescendant(selection.anchorNode)) {
            var selectionText;
            // workaround an issue with Microsoft Edge as copied line breaks
            // are removed otherwise from the selection string
            if (window.navigator.userAgent.indexOf('Edge') !== -1) {
                selectionText = edgeGetSelectedCodeLines(selection);
            } else {
                // other browsers can directly use the selection string
                selectionText = selection.toString();
            }
            e.clipboardData.setData('text/plain', selectionText);
            e.preventDefault();
        }
    });

    function addStyles () {
        var css = d.createElement('style');
        css.type = 'text/css';
        css.innerHTML = format(
            '.{0}{border-collapse:collapse}' +
            '.{0} td{padding:0}' +
            '.{1}:before{content:attr({2})}',
        [
            TABLE_NAME,
            NUMBER_LINE_NAME,
            DATA_ATTR_NAME
        ]);
        d.getElementsByTagName('head')[0].appendChild(css);
    }

    function initLineNumbersOnLoad (options) {
        if (d.readyState === 'interactive' || d.readyState === 'complete') {
            documentReady(options);
        } else {
            w.addEventListener('DOMContentLoaded', function () {
                documentReady(options);
            });
        }
    }

    function documentReady (options) {
        try {
            var blocks = d.querySelectorAll('code.hljs,code.nohighlight');

            for (var i in blocks) {
                if (blocks.hasOwnProperty(i)) {
                    if (!isPluginDisabledForBlock(blocks[i])) {
                        lineNumbersBlock(blocks[i], options);
                    }
                }
            }
        } catch (e) {
            w.console.error('LineNumbers error: ', e);
        }
    }

    function isPluginDisabledForBlock(element) {
        return element.classList.contains('nohljsln');
    }

    function lineNumbersBlock (element, options) {
        if (typeof element !== 'object') return;

        async(function () {
            element.innerHTML = lineNumbersInternal(element, options);
        });
    }

    function lineNumbersValue (value, options) {
        if (typeof value !== 'string') return;

        var element = document.createElement('code')
        element.innerHTML = value

        return lineNumbersInternal(element, options);
    }

    function lineNumbersInternal (element, options) {

        var internalOptions = mapOptions(element, options);

        duplicateMultilineNodes(element);

        return addLineNumbersBlockFor(element.innerHTML, internalOptions);
    }

    function addLineNumbersBlockFor (inputHtml, options) {
        var lines = getLines(inputHtml);

        // if last line contains only carriage return remove it
        if (lines[lines.length-1].trim() === '') {
            lines.pop();
        }

        if (lines.length > 1 || options.singleLine) {
            var html = '';

            for (var i = 0, l = lines.length; i < l; i++) {
                html += format(
                    '<tr>' +
                        '<td class="{0} {1}" {3}="{5}">' +
                            '<div class="{2}" {3}="{5}"></div>' +
                        '</td>' +
                        '<td class="{0} {4}" {3}="{5}">' +
                            '{6}' +
                        '</td>' +
                    '</tr>',
                [
                    LINE_NAME,
                    NUMBERS_BLOCK_NAME,
                    NUMBER_LINE_NAME,
                    DATA_ATTR_NAME,
                    CODE_BLOCK_NAME,
                    i + options.startFrom,
                    lines[i].length > 0 ? lines[i] : ' '
                ]);
            }

            return format('<table class="{0}">{1}</table>', [ TABLE_NAME, html ]);
        }

        return inputHtml;
    }

    /**
     * @param {HTMLElement} element Code block.
     * @param {Object} options External API options.
     * @returns {Object} Internal API options.
     */
    function mapOptions (element, options) {
        options = options || {};
        return {
            singleLine: getSingleLineOption(options),
            startFrom: getStartFromOption(element, options)
        };
    }

    function getSingleLineOption (options) {
        var defaultValue = false;
        if (!!options.singleLine) {
            return options.singleLine;
        }
        return defaultValue;
    }

    function getStartFromOption (element, options) {
        var defaultValue = 1;
        var startFrom = defaultValue;

        if (isFinite(options.startFrom)) {
            startFrom = options.startFrom;
        }

        // can be overridden because local option is priority
        var value = getAttribute(element, 'data-ln-start-from');
        if (value !== null) {
            startFrom = toNumber(value, defaultValue);
        }

        return startFrom;
    }

    /**
     * Recursive method for fix multi-line elements implementation in highlight.js
     * Doing deep passage on child nodes.
     * @param {HTMLElement} element
     */
    function duplicateMultilineNodes (element) {
        var nodes = element.childNodes;
        for (var node in nodes) {
            if (nodes.hasOwnProperty(node)) {
                var child = nodes[node];
                if (getLinesCount(child.textContent) > 0) {
                    if (child.childNodes.length > 0) {
                        duplicateMultilineNodes(child);
                    } else {
                        duplicateMultilineNode(child.parentNode);
                    }
                }
            }
        }
    }

    /**
     * Method for fix multi-line elements implementation in highlight.js
     * @param {HTMLElement} element
     */
    function duplicateMultilineNode (element) {
        var className = element.className;

        if ( ! /hljs-/.test(className)) return;

        var lines = getLines(element.innerHTML);

        for (var i = 0, result = ''; i < lines.length; i++) {
            var lineText = lines[i].length > 0 ? lines[i] : ' ';
            result += format('<span class="{0}">{1}</span>\n', [ className,  lineText ]);
        }

        element.innerHTML = result.trim();
    }

    function getLines (text) {
        if (text.length === 0) return [];
        return text.split(BREAK_LINE_REGEXP);
    }

    function getLinesCount (text) {
        return (text.trim().match(BREAK_LINE_REGEXP) || []).length;
    }

    ///
    /// HELPERS
    ///

    function async (func) {
        w.setTimeout(func, 0);
    }

    /**
     * @param {string} format
     * @param {array} args
     */
    function format (format, args) {
        return format.replace(/\{(\d+)\}/g, function(m, n){
            return args[n] !== undefined ? args[n] : m;
        });
    }

    /**
     * @param {HTMLElement} element Code block.
     * @param {String} attrName Attribute name.
     * @returns {String} Attribute value or empty.
     */
    function getAttribute (element, attrName) {
        return element.hasAttribute(attrName) ? element.getAttribute(attrName) : null;
    }

    /**
     * @param {String} str Source string.
     * @param {Number} fallback Fallback value.
     * @returns Parsed number or fallback value.
     */
    function toNumber (str, fallback) {
        if (!str) return fallback;
        var number = Number(str);
        return isFinite(number) ? number : fallback;
    }

}(window, document));
