var Markdown;

if (typeof exports === "object" && typeof require === "function") // we're in a CommonJS (e.g. Node.js) module
    Markdown = exports;
else
    Markdown = {};

// The following text is included for historical reasons, but should
// be taken with a pinch of salt; it's not all true anymore.

//
// Wherever possible, Showdown is a straight, line-by-line port
// of the Perl version of Markdown.
//
// This is not a normal parser design; it's basically just a
// series of string substitutions.  It's hard to read and
// maintain this way,  but keeping Showdown close to the original
// design makes it easier to port new features.
//
// More importantly, Showdown behaves like markdown.pl in most
// edge cases.  So web applications can do client-side preview
// in Javascript, and then build identical HTML on the server.
//
// This port needs the new RegExp functionality of ECMA 262,
// 3rd Edition (i.e. Javascript 1.5).  Most modern web browsers
// should do fine.  Even with the new regular expression features,
// We do a lot of work to emulate Perl's regex functionality.
// The tricky changes in this file mostly have the "attacklab:"
// label.  Major or self-explanatory changes don't.
//
// Smart diff tools like Araxis Merge will be able to match up
// this file with markdown.pl in a useful way.  A little tweaking
// helps: in a copy of markdown.pl, replace "#" with "//" and
// replace "$text" with "text".  Be sure to ignore whitespace
// and line endings.
//


//
// Usage:
//
//   var text = "Markdown *rocks*.";
//
//   var converter = new Markdown.Converter();
//   var html = converter.makeHtml(text);
//
//   alert(html);
//
// Note: move the sample code to the bottom of this
// file before uncommenting it.
//

(function () {

    function identity(x) { return x; }
    function returnFalse(x) { return false; }

    function HookCollection() { }

    HookCollection.prototype = {

        chain: function (hookname, func) {
            var original = this[hookname];
            if (!original)
                throw new Error("unknown hook " + hookname);

            if (original === identity)
                this[hookname] = func;
            else
                this[hookname] = function (x) { return func(original(x)); }
        },
        set: function (hookname, func) {
            if (!this[hookname])
                throw new Error("unknown hook " + hookname);
            this[hookname] = func;
        },
        addNoop: function (hookname) {
            this[hookname] = identity;
        },
        addFalse: function (hookname) {
            this[hookname] = returnFalse;
        }
    };

    Markdown.HookCollection = HookCollection;

    // g_urls and g_titles allow arbitrary user-entered strings as keys. This
    // caused an exception (and hence stopped the rendering) when the user entered
    // e.g. [push] or [__proto__]. Adding a prefix to the actual key prevents this
    // (since no builtin property starts with "s_"). See
    // http://meta.stackoverflow.com/questions/64655/strange-wmd-bug
    // (granted, switching from Array() to Object() alone would have left only __proto__
    // to be a problem)
    function SaveHash() { }
    SaveHash.prototype = {
        set: function (key, value) {
            this["s_" + key] = value;
        },
        get: function (key) {
            return this["s_" + key];
        }
    };

    Markdown.Converter = function () {
        var pluginHooks = this.hooks = new HookCollection();
        pluginHooks.addNoop("plainLinkText");  // given a URL that was encountered by itself (without markup), should return the link text that's to be given to this link
        pluginHooks.addNoop("preConversion");  // called with the orignal text as given to makeHtml. The result of this plugin hook is the actual markdown source that will be cooked
        pluginHooks.addNoop("postConversion"); // called with the final cooked HTML code. The result of this plugin hook is the actual output of makeHtml

        //
        // Private state of the converter instance:
        //

        // Global hashes, used by various utility routines
        var g_urls;
        var g_titles;
        var g_html_blocks;

        // Used to track when we're inside an ordered or unordered list
        // (see _ProcessListItems() for details):
        var g_list_level;

        this.makeHtml = function (text) {

            //
            // Main function. The order in which other subs are called here is
            // essential. Link and image substitutions need to happen before
            // _EscapeSpecialCharsWithinTagAttributes(), so that any *'s or _'s in the <a>
            // and <img> tags get encoded.
            //

            // This will only happen if makeHtml on the same converter instance is called from a plugin hook.
            // Don't do that.
            if (g_urls)
                throw new Error("Recursive call to converter.makeHtml");

            // Create the private state objects.
            g_urls = new SaveHash();
            g_titles = new SaveHash();
            g_html_blocks = [];
            g_list_level = 0;

            text = pluginHooks.preConversion(text);

            // attacklab: Replace ~ with ~T
            // This lets us use tilde as an escape char to avoid md5 hashes
            // The choice of character is arbitray; anything that isn't
            // magic in Markdown will work.
            text = text.replace(/~/g, "~T");

            // attacklab: Replace $ with ~D
            // RegExp interprets $ as a special character
            // when it's in a replacement string
            text = text.replace(/\$/g, "~D");

            // Standardize line endings
            text = text.replace(/\r\n/g, "\n"); // DOS to Unix
            text = text.replace(/\r/g, "\n"); // Mac to Unix

            // Make sure text begins and ends with a couple of newlines:
            text = "\n\n" + text + "\n\n";

            // Convert all tabs to spaces.
            text = _Detab(text);

            // Strip any lines consisting only of spaces and tabs.
            // This makes subsequent regexen easier to write, because we can
            // match consecutive blank lines with /\n+/ instead of something
            // contorted like /[ \t]*\n+/ .
            text = text.replace(/^[ \t]+$/mg, "");

            // Turn block-level HTML blocks into hash entries
            text = _HashHTMLBlocks(text);

            // Strip link definitions, store in hashes.
            text = _StripLinkDefinitions(text);

            text = _RunBlockGamut(text);

            text = _UnescapeSpecialChars(text);

            // attacklab: Restore dollar signs
            text = text.replace(/~D/g, "$$");

            // attacklab: Restore tildes
            text = text.replace(/~T/g, "~");

            text = pluginHooks.postConversion(text);

            g_html_blocks = g_titles = g_urls = null;

            return text;
        };

        function _StripLinkDefinitions(text) {
            //
            // Strips link definitions from text, stores the URLs and titles in
            // hash references.
            //

            // Link defs are in the form: ^[id]: url "optional title"

            /*
             text = text.replace(/
             ^[ ]{0,3}\[(.+)\]:  // id = $1  attacklab: g_tab_width - 1
             [ \t]*
             \n?                 // maybe *one* newline
             [ \t]*
             <?(\S+?)>?          // url = $2
             (?=\s|$)            // lookahead for whitespace instead of the lookbehind removed below
             [ \t]*
             \n?                 // maybe one newline
             [ \t]*
             (                   // (potential) title = $3
             (\n*)           // any lines skipped = $4 attacklab: lookbehind removed
             [ \t]+
             ["(]
             (.+?)           // title = $5
             [")]
             [ \t]*
             )?                  // title is optional
             (?:\n+|$)
             /gm, function(){...});
             */

            text = text.replace(/^[ ]{0,3}\[(.+)\]:[ \t]*\n?[ \t]*<?(\S+?)>?(?=\s|$)[ \t]*\n?[ \t]*((\n*)["(](.+?)[")][ \t]*)?(?:\n+)/gm,
                function (wholeMatch, m1, m2, m3, m4, m5) {
                    m1 = m1.toLowerCase();
                    g_urls.set(m1, _EncodeAmpsAndAngles(m2));  // Link IDs are case-insensitive
                    if (m4) {
                        // Oops, found blank lines, so it's not a title.
                        // Put back the parenthetical statement we stole.
                        return m3;
                    } else if (m5) {
                        g_titles.set(m1, m5.replace(/"/g, "&quot;"));
                    }

                    // Completely remove the definition from the text
                    return "";
                }
            );

            return text;
        }

        function _HashHTMLBlocks(text) {

            // Hashify HTML blocks:
            // We only want to do this for block-level HTML tags, such as headers,
            // lists, and tables. That's because we still want to wrap <p>s around
            // "paragraphs" that are wrapped in non-block-level tags, such as anchors,
            // phrase emphasis, and spans. The list of tags we're looking for is
            // hard-coded:
            var block_tags_a = "p|div|h[1-6]|blockquote|pre|table|dl|ol|ul|script|noscript|form|fieldset|iframe|math|ins|del"
            var block_tags_b = "p|div|h[1-6]|blockquote|pre|table|dl|ol|ul|script|noscript|form|fieldset|iframe|math"

            // First, look for nested blocks, e.g.:
            //   <div>
            //     <div>
            //     tags for inner block must be indented.
            //     </div>
            //   </div>
            //
            // The outermost tags must start at the left margin for this to match, and
            // the inner nested divs must be indented.
            // We need to do this before the next, more liberal match, because the next
            // match will start at the first `<div>` and stop at the first `</div>`.

            // attacklab: This regex can be expensive when it fails.

            /*
             text = text.replace(/
             (                       // save in $1
             ^                   // start of line  (with /m)
             <($block_tags_a)    // start tag = $2
             \b                  // word break
             // attacklab: hack around khtml/pcre bug...
             [^\r]*?\n           // any number of lines, minimally matching
             </\2>               // the matching end tag
             [ \t]*              // trailing spaces/tabs
             (?=\n+)             // followed by a newline
             )                       // attacklab: there are sentinel newlines at end of document
             /gm,function(){...}};
             */
            text = text.replace(/^(<(p|div|h[1-6]|blockquote|pre|table|dl|ol|ul|script|noscript|form|fieldset|iframe|math|ins|del)\b[^\r]*?\n<\/\2>[ \t]*(?=\n+))/gm, hashElement);

            //
            // Now match more liberally, simply from `\n<tag>` to `</tag>\n`
            //

            /*
             text = text.replace(/
             (                       // save in $1
             ^                   // start of line  (with /m)
             <($block_tags_b)    // start tag = $2
             \b                  // word break
             // attacklab: hack around khtml/pcre bug...
             [^\r]*?             // any number of lines, minimally matching
             .*</\2>             // the matching end tag
             [ \t]*              // trailing spaces/tabs
             (?=\n+)             // followed by a newline
             )                       // attacklab: there are sentinel newlines at end of document
             /gm,function(){...}};
             */
            text = text.replace(/^(<(p|div|h[1-6]|blockquote|pre|table|dl|ol|ul|script|noscript|form|fieldset|iframe|math)\b[^\r]*?.*<\/\2>[ \t]*(?=\n+)\n)/gm, hashElement);

            // Special case just for <hr />. It was easier to make a special case than
            // to make the other regex more complicated.

            /*
             text = text.replace(/
             \n                  // Starting after a blank line
             [ ]{0,3}
             (                   // save in $1
             (<(hr)          // start tag = $2
             \b          // word break
             ([^<>])*?
             \/?>)           // the matching end tag
             [ \t]*
             (?=\n{2,})      // followed by a blank line
             )
             /g,hashElement);
             */
            text = text.replace(/\n[ ]{0,3}((<(hr)\b([^<>])*?\/?>)[ \t]*(?=\n{2,}))/g, hashElement);

            // Special case for standalone HTML comments:

            /*
             text = text.replace(/
             \n\n                                            // Starting after a blank line
             [ ]{0,3}                                        // attacklab: g_tab_width - 1
             (                                               // save in $1
             <!
             (--(?:|(?:[^>-]|-[^>])(?:[^-]|-[^-])*)--)   // see http://www.w3.org/TR/html-markup/syntax.html#comments and http://meta.stackoverflow.com/q/95256
             >
             [ \t]*
             (?=\n{2,})                                  // followed by a blank line
             )
             /g,hashElement);
             */
            text = text.replace(/\n\n[ ]{0,3}(<!(--(?:|(?:[^>-]|-[^>])(?:[^-]|-[^-])*)--)>[ \t]*(?=\n{2,}))/g, hashElement);

            // PHP and ASP-style processor instructions (<?...?> and <%...%>)

            /*
             text = text.replace(/
             (?:
             \n\n            // Starting after a blank line
             )
             (                   // save in $1
             [ ]{0,3}        // attacklab: g_tab_width - 1
             (?:
             <([?%])     // $2
             [^\r]*?
             \2>
             )
             [ \t]*
             (?=\n{2,})      // followed by a blank line
             )
             /g,hashElement);
             */
            text = text.replace(/(?:\n\n)([ ]{0,3}(?:<([?%])[^\r]*?\2>)[ \t]*(?=\n{2,}))/g, hashElement);

            return text;
        }

        function hashElement(wholeMatch, m1) {
            var blockText = m1;

            // Undo double lines
            blockText = blockText.replace(/^\n+/, "");

            // strip trailing blank lines
            blockText = blockText.replace(/\n+$/g, "");

            // Replace the element text with a marker ("~KxK" where x is its key)
            blockText = "\n\n~K" + (g_html_blocks.push(blockText) - 1) + "K\n\n";

            return blockText;
        }

        function _RunBlockGamut(text, doNotUnhash) {
            //
            // These are all the transformations that form block-level
            // tags like paragraphs, headers, and list items.
            //
            text = _DoHeaders(text);

            // Do Horizontal Rules:
            var replacement = "<hr />\n";
            text = text.replace(/^[ ]{0,2}([ ]?\*[ ]?){3,}[ \t]*$/gm, replacement);
            text = text.replace(/^[ ]{0,2}([ ]?-[ ]?){3,}[ \t]*$/gm, replacement);
            text = text.replace(/^[ ]{0,2}([ ]?_[ ]?){3,}[ \t]*$/gm, replacement);

            text = _DoLists(text);
            text = _DoCodeBlocks(text);
            text = _DoBlockQuotes(text);

            // We already ran _HashHTMLBlocks() before, in Markdown(), but that
            // was to escape raw HTML in the original Markdown source. This time,
            // we're escaping the markup we've just created, so that we don't wrap
            // <p> tags around block-level tags.
            text = _HashHTMLBlocks(text);
            text = _FormParagraphs(text, doNotUnhash);

            return text;
        }

        function _RunSpanGamut(text) {
            //
            // These are all the transformations that occur *within* block-level
            // tags like paragraphs, headers, and list items.
            //

            text = _DoCodeSpans(text);
            text = _EscapeSpecialCharsWithinTagAttributes(text);
            text = _EncodeBackslashEscapes(text);

            // Process anchor and image tags. Images must come first,
            // because ![foo][f] looks like an anchor.
            text = _DoImages(text);
            text = _DoAnchors(text);

            // Make links out of things like `<http://example.com/>`
            // Must come after _DoAnchors(), because you can use < and >
            // delimiters in inline links like [this](<url>).
            text = _DoAutoLinks(text);

            text = text.replace(/~P/g, "://"); // put in place to prevent autolinking; reset now

            text = _EncodeAmpsAndAngles(text);
            text = _DoItalicsAndBold(text);

            // Do hard breaks:
            text = text.replace(/  +\n/g, " <br>\n");

            return text;
        }

        function _EscapeSpecialCharsWithinTagAttributes(text) {
            //
            // Within tags -- meaning between < and > -- encode [\ ` * _] so they
            // don't conflict with their use in Markdown for code, italics and strong.
            //

            // Build a regex to find HTML tags and comments.  See Friedl's
            // "Mastering Regular Expressions", 2nd Ed., pp. 200-201.

            // SE: changed the comment part of the regex

            var regex = /(<[a-z\/!$]("[^"]*"|'[^']*'|[^'">])*>|<!(--(?:|(?:[^>-]|-[^>])(?:[^-]|-[^-])*)--)>)/gi;

            text = text.replace(regex, function (wholeMatch) {
                var tag = wholeMatch.replace(/(.)<\/?code>(?=.)/g, "$1`");
                tag = escapeCharacters(tag, wholeMatch.charAt(1) == "!" ? "\\`*_/" : "\\`*_"); // also escape slashes in comments to prevent autolinking there -- http://meta.stackoverflow.com/questions/95987
                return tag;
            });

            return text;
        }

        function _DoAnchors(text) {
            //
            // Turn Markdown link shortcuts into XHTML <a> tags.
            //
            //
            // First, handle reference-style links: [link text] [id]
            //

            /*
             text = text.replace(/
             (                           // wrap whole match in $1
             \[
             (
             (?:
             \[[^\]]*\]      // allow brackets nested one level
             |
             [^\[]           // or anything else
             )*
             )
             \]

             [ ]?                    // one optional space
             (?:\n[ ]*)?             // one optional newline followed by spaces

             \[
             (.*?)                   // id = $3
             \]
             )
             ()()()()                    // pad remaining backreferences
             /g, writeAnchorTag);
             */
            text = text.replace(/(\[((?:\[[^\]]*\]|[^\[\]])*)\][ ]?(?:\n[ ]*)?\[(.*?)\])()()()()/g, writeAnchorTag);

            //
            // Next, inline-style links: [link text](url "optional title")
            //

            /*
             text = text.replace(/
             (                           // wrap whole match in $1
             \[
             (
             (?:
             \[[^\]]*\]      // allow brackets nested one level
             |
             [^\[\]]         // or anything else
             )*
             )
             \]
             \(                      // literal paren
             [ \t]*
             ()                      // no id, so leave $3 empty
             <?(                     // href = $4
             (?:
             \([^)]*\)       // allow one level of (correctly nested) parens (think MSDN)
             |
             [^()]
             )*?
             )>?
             [ \t]*
             (                       // $5
             (['"])              // quote char = $6
             (.*?)               // Title = $7
             \6                  // matching quote
             [ \t]*              // ignore any spaces/tabs between closing quote and )
             )?                      // title is optional
             \)
             )
             /g, writeAnchorTag);
             */

            text = text.replace(/(\[((?:\[[^\]]*\]|[^\[\]])*)\]\([ \t]*()<?((?:\([^)]*\)|[^()])*?)>?[ \t]*((['"])(.*?)\6[ \t]*)?\))/g, writeAnchorTag);

            //
            // Last, handle reference-style shortcuts: [link text]
            // These must come last in case you've also got [link test][1]
            // or [link test](/foo)
            //

            /*
             text = text.replace(/
             (                   // wrap whole match in $1
             \[
             ([^\[\]]+)      // link text = $2; can't contain '[' or ']'
             \]
             )
             ()()()()()          // pad rest of backreferences
             /g, writeAnchorTag);
             */
            text = text.replace(/(\[([^\[\]]+)\])()()()()()/g, writeAnchorTag);

            return text;
        }

        function writeAnchorTag(wholeMatch, m1, m2, m3, m4, m5, m6, m7) {
            if (m7 == undefined) m7 = "";
            var whole_match = m1;
            var link_text = m2.replace(/:\/\//g, "~P"); // to prevent auto-linking withing the link. will be converted back after the auto-linker runs
            var link_id = m3.toLowerCase();
            var url = m4;
            var title = m7;

            if (url == "") {
                if (link_id == "") {
                    // lower-case and turn embedded newlines into spaces
                    link_id = link_text.toLowerCase().replace(/ ?\n/g, " ");
                }
                url = "#" + link_id;

                if (g_urls.get(link_id) != undefined) {
                    url = g_urls.get(link_id);
                    if (g_titles.get(link_id) != undefined) {
                        title = g_titles.get(link_id);
                    }
                }
                else {
                    if (whole_match.search(/\(\s*\)$/m) > -1) {
                        // Special case for explicit empty url
                        url = "";
                    } else {
                        return whole_match;
                    }
                }
            }
            url = encodeProblemUrlChars(url);
            url = escapeCharacters(url, "*_");
            var result = "<a href=\"" + url + "\"";

            if (title != "") {
                title = attributeEncode(title);
                title = escapeCharacters(title, "*_");
                result += " title=\"" + title + "\"";
            }

            result += ">" + link_text + "</a>";

            return result;
        }

        function _DoImages(text) {
            //
            // Turn Markdown image shortcuts into <img> tags.
            //

            //
            // First, handle reference-style labeled images: ![alt text][id]
            //

            /*
             text = text.replace(/
             (                   // wrap whole match in $1
             !\[
             (.*?)           // alt text = $2
             \]

             [ ]?            // one optional space
             (?:\n[ ]*)?     // one optional newline followed by spaces

             \[
             (.*?)           // id = $3
             \]
             )
             ()()()()            // pad rest of backreferences
             /g, writeImageTag);
             */
            text = text.replace(/(!\[(.*?)\][ ]?(?:\n[ ]*)?\[(.*?)\])()()()()/g, writeImageTag);

            //
            // Next, handle inline images:  ![alt text](url "optional title")
            // Don't forget: encode * and _

            /*
             text = text.replace(/
             (                   // wrap whole match in $1
             !\[
             (.*?)           // alt text = $2
             \]
             \s?             // One optional whitespace character
             \(              // literal paren
             [ \t]*
             ()              // no id, so leave $3 empty
             <?(\S+?)>?      // src url = $4
             [ \t]*
             (               // $5
             (['"])      // quote char = $6
             (.*?)       // title = $7
             \6          // matching quote
             [ \t]*
             )?              // title is optional
             \)
             )
             /g, writeImageTag);
             */
            text = text.replace(/(!\[(.*?)\]\s?\([ \t]*()<?(\S+?)>?[ \t]*((['"])(.*?)\6[ \t]*)?\))/g, writeImageTag);

            return text;
        }

        function attributeEncode(text) {
            // unconditionally replace angle brackets here -- what ends up in an attribute (e.g. alt or title)
            // never makes sense to have verbatim HTML in it (and the sanitizer would totally break it)
            return text.replace(/>/g, "&gt;").replace(/</g, "&lt;").replace(/"/g, "&quot;");
        }

        function writeImageTag(wholeMatch, m1, m2, m3, m4, m5, m6, m7) {
            var whole_match = m1;
            var alt_text = m2;
            var link_id = m3.toLowerCase();
            var url = m4;
            var title = m7;

            if (!title) title = "";

            if (url == "") {
                if (link_id == "") {
                    // lower-case and turn embedded newlines into spaces
                    link_id = alt_text.toLowerCase().replace(/ ?\n/g, " ");
                }
                url = "#" + link_id;

                if (g_urls.get(link_id) != undefined) {
                    url = g_urls.get(link_id);
                    if (g_titles.get(link_id) != undefined) {
                        title = g_titles.get(link_id);
                    }
                }
                else {
                    return whole_match;
                }
            }

            alt_text = escapeCharacters(attributeEncode(alt_text), "*_[]()");
            url = escapeCharacters(url, "*_");
            var result = "<img src=\"" + url + "\" alt=\"" + alt_text + "\"";

            // attacklab: Markdown.pl adds empty title attributes to images.
            // Replicate this bug.

            //if (title != "") {
            title = attributeEncode(title);
            title = escapeCharacters(title, "*_");
            result += " title=\"" + title + "\"";
            //}

            result += " />";

            return result;
        }

        function _DoHeaders(text) {

            // Setext-style headers:
            //  Header 1
            //  ========
            //
            //  Header 2
            //  --------
            //
            text = text.replace(/^(.+)[ \t]*\n=+[ \t]*\n+/gm,
                function (wholeMatch, m1) { return "<h1>" + _RunSpanGamut(m1) + "</h1>\n\n"; }
            );

            text = text.replace(/^(.+)[ \t]*\n-+[ \t]*\n+/gm,
                function (matchFound, m1) { return "<h2>" + _RunSpanGamut(m1) + "</h2>\n\n"; }
            );

            // atx-style headers:
            //  # Header 1
            //  ## Header 2
            //  ## Header 2 with closing hashes ##
            //  ...
            //  ###### Header 6
            //

            /*
             text = text.replace(/
             ^(\#{1,6})      // $1 = string of #'s
             [ \t]*
             (.+?)           // $2 = Header text
             [ \t]*
             \#*             // optional closing #'s (not counted)
             \n+
             /gm, function() {...});
             */

            text = text.replace(/^(\#{1,6})[ \t]*(.+?)[ \t]*\#*\n+/gm,
                function (wholeMatch, m1, m2) {
                    var h_level = m1.length;
                    return "<h" + h_level + ">" + _RunSpanGamut(m2) + "</h" + h_level + ">\n\n";
                }
            );

            return text;
        }

        function _DoLists(text) {
            //
            // Form HTML ordered (numbered) and unordered (bulleted) lists.
            //

            // attacklab: add sentinel to hack around khtml/safari bug:
            // http://bugs.webkit.org/show_bug.cgi?id=11231
            text += "~0";

            // Re-usable pattern to match any entirel ul or ol list:

            /*
             var whole_list = /
             (                                   // $1 = whole list
             (                               // $2
             [ ]{0,3}                    // attacklab: g_tab_width - 1
             ([*+-]|\d+[.])              // $3 = first list item marker
             [ \t]+
             )
             [^\r]+?
             (                               // $4
             ~0                          // sentinel for workaround; should be $
             |
             \n{2,}
             (?=\S)
             (?!                         // Negative lookahead for another list item marker
             [ \t]*
             (?:[*+-]|\d+[.])[ \t]+
             )
             )
             )
             /g
             */
            var whole_list = /^(([ ]{0,3}([*+-]|\d+[.])[ \t]+)[^\r]+?(~0|\n{2,}(?=\S)(?![ \t]*(?:[*+-]|\d+[.])[ \t]+)))/gm;

            if (g_list_level) {
                text = text.replace(whole_list, function (wholeMatch, m1, m2) {
                    var list = m1;
                    var list_type = (m2.search(/[*+-]/g) > -1) ? "ul" : "ol";

                    var result = _ProcessListItems(list, list_type);

                    // Trim any trailing whitespace, to put the closing `</$list_type>`
                    // up on the preceding line, to get it past the current stupid
                    // HTML block parser. This is a hack to work around the terrible
                    // hack that is the HTML block parser.
                    result = result.replace(/\s+$/, "");
                    result = "<" + list_type + ">" + result + "</" + list_type + ">\n";
                    return result;
                });
            } else {
                whole_list = /(\n\n|^\n?)(([ ]{0,3}([*+-]|\d+[.])[ \t]+)[^\r]+?(~0|\n{2,}(?=\S)(?![ \t]*(?:[*+-]|\d+[.])[ \t]+)))/g;
                text = text.replace(whole_list, function (wholeMatch, m1, m2, m3) {
                    var runup = m1;
                    var list = m2;

                    var list_type = (m3.search(/[*+-]/g) > -1) ? "ul" : "ol";
                    var result = _ProcessListItems(list, list_type);
                    result = runup + "<" + list_type + ">\n" + result + "</" + list_type + ">\n";
                    return result;
                });
            }

            // attacklab: strip sentinel
            text = text.replace(/~0/, "");

            return text;
        }

        var _listItemMarkers = { ol: "\\d+[.]", ul: "[*+-]" };

        function _ProcessListItems(list_str, list_type) {
            //
            //  Process the contents of a single ordered or unordered list, splitting it
            //  into individual list items.
            //
            //  list_type is either "ul" or "ol".

            // The $g_list_level global keeps track of when we're inside a list.
            // Each time we enter a list, we increment it; when we leave a list,
            // we decrement. If it's zero, we're not in a list anymore.
            //
            // We do this because when we're not inside a list, we want to treat
            // something like this:
            //
            //    I recommend upgrading to version
            //    8. Oops, now this line is treated
            //    as a sub-list.
            //
            // As a single paragraph, despite the fact that the second line starts
            // with a digit-period-space sequence.
            //
            // Whereas when we're inside a list (or sub-list), that line will be
            // treated as the start of a sub-list. What a kludge, huh? This is
            // an aspect of Markdown's syntax that's hard to parse perfectly
            // without resorting to mind-reading. Perhaps the solution is to
            // change the syntax rules such that sub-lists must start with a
            // starting cardinal number; e.g. "1." or "a.".

            g_list_level++;

            // trim trailing blank lines:
            list_str = list_str.replace(/\n{2,}$/, "\n");

            // attacklab: add sentinel to emulate \z
            list_str += "~0";

            // In the original attacklab showdown, list_type was not given to this function, and anything
            // that matched /[*+-]|\d+[.]/ would just create the next <li>, causing this mismatch:
            //
            //  Markdown          rendered by WMD        rendered by MarkdownSharp
            //  ------------------------------------------------------------------
            //  1. first          1. first               1. first
            //  2. second         2. second              2. second
            //  - third           3. third                   * third
            //
            // We changed this to behave identical to MarkdownSharp. This is the constructed RegEx,
            // with {MARKER} being one of \d+[.] or [*+-], depending on list_type:

            /*
             list_str = list_str.replace(/
             (^[ \t]*)                       // leading whitespace = $1
             ({MARKER}) [ \t]+               // list marker = $2
             ([^\r]+?                        // list item text   = $3
             (\n+)
             )
             (?=
             (~0 | \2 ({MARKER}) [ \t]+)
             )
             /gm, function(){...});
             */

            var marker = _listItemMarkers[list_type];
            var re = new RegExp("(^[ \\t]*)(" + marker + ")[ \\t]+([^\\r]+?(\\n+))(?=(~0|\\1(" + marker + ")[ \\t]+))", "gm");
            var last_item_had_a_double_newline = false;
            list_str = list_str.replace(re,
                function (wholeMatch, m1, m2, m3) {
                    var item = m3;
                    var leading_space = m1;
                    var ends_with_double_newline = /\n\n$/.test(item);
                    var contains_double_newline = ends_with_double_newline || item.search(/\n{2,}/) > -1;

                    if (contains_double_newline || last_item_had_a_double_newline) {
                        item = _RunBlockGamut(_Outdent(item), /* doNotUnhash = */true);
                    }
                    else {
                        // Recursion for sub-lists:
                        item = _DoLists(_Outdent(item));
                        item = item.replace(/\n$/, ""); // chomp(item)
                        item = _RunSpanGamut(item);
                    }
                    last_item_had_a_double_newline = ends_with_double_newline;
                    return "<li>" + item + "</li>\n";
                }
            );

            // attacklab: strip sentinel
            list_str = list_str.replace(/~0/g, "");

            g_list_level--;
            return list_str;
        }

        function _DoCodeBlocks(text) {
            //
            //  Process Markdown `<pre><code>` blocks.
            //

            /*
             text = text.replace(/
             (?:\n\n|^)
             (                               // $1 = the code block -- one or more lines, starting with a space/tab
             (?:
             (?:[ ]{4}|\t)           // Lines must start with a tab or a tab-width of spaces - attacklab: g_tab_width
             .*\n+
             )+
             )
             (\n*[ ]{0,3}[^ \t\n]|(?=~0))    // attacklab: g_tab_width
             /g ,function(){...});
             */

            // attacklab: sentinel workarounds for lack of \A and \Z, safari\khtml bug
            text += "~0";

            text = text.replace(/(?:\n\n|^)((?:(?:[ ]{4}|\t).*\n+)+)(\n*[ ]{0,3}[^ \t\n]|(?=~0))/g,
                function (wholeMatch, m1, m2) {
                    var codeblock = m1;
                    var nextChar = m2;

                    codeblock = _EncodeCode(_Outdent(codeblock));
                    codeblock = _Detab(codeblock);
                    codeblock = codeblock.replace(/^\n+/g, ""); // trim leading newlines
                    codeblock = codeblock.replace(/\n+$/g, ""); // trim trailing whitespace

                    codeblock = '<pre class="prettyprint linenums"><code>' + codeblock + '\n</code></pre>';

                    return "\n\n" + codeblock + "\n\n" + nextChar;
                }
            );

            // attacklab: strip sentinel
            text = text.replace(/~0/, "");

            return text;
        }

        function hashBlock(text) {
            text = text.replace(/(^\n+|\n+$)/g, "");
            return "\n\n~K" + (g_html_blocks.push(text) - 1) + "K\n\n";
        }

        function _DoCodeSpans(text) {
            //
            // * Backtick quotes are used for <code></code> spans.
            //
            // * You can use multiple backticks as the delimiters if you want to
            //   include literal backticks in the code span. So, this input:
            //
            //      Just type ``foo `bar` baz`` at the prompt.
            //
            //   Will translate to:
            //
            //      <p>Just type <code>foo `bar` baz</code> at the prompt.</p>
            //
            //   There's no arbitrary limit to the number of backticks you
            //   can use as delimters. If you need three consecutive backticks
            //   in your code, use four for delimiters, etc.
            //
            // * You can use spaces to get literal backticks at the edges:
            //
            //      ... type `` `bar` `` ...
            //
            //   Turns to:
            //
            //      ... type <code>`bar`</code> ...
            //

            /*
             text = text.replace(/
             (^|[^\\])       // Character before opening ` can't be a backslash
             (`+)            // $2 = Opening run of `
             (               // $3 = The code block
             [^\r]*?
             [^`]        // attacklab: work around lack of lookbehind
             )
             \2              // Matching closer
             (?!`)
             /gm, function(){...});
             */

            text = text.replace(/(^|[^\\])(`+)([^\r]*?[^`])\2(?!`)/gm,
                function (wholeMatch, m1, m2, m3, m4) {
                    var c = m3;
                    c = c.replace(/^([ \t]*)/g, ""); // leading whitespace
                    c = c.replace(/[ \t]*$/g, ""); // trailing whitespace
                    c = _EncodeCode(c);
                    c = c.replace(/:\/\//g, "~P"); // to prevent auto-linking. Not necessary in code *blocks*, but in code spans. Will be converted back after the auto-linker runs.
                    return m1 + "<code>" + c + "</code>";
                }
            );

            return text;
        }

        function _EncodeCode(text) {
            //
            // Encode/escape certain characters inside Markdown code runs.
            // The point is that in code, these characters are literals,
            // and lose their special Markdown meanings.
            //
            // Encode all ampersands; HTML entities are not
            // entities within a Markdown code span.
            text = text.replace(/&/g, "&amp;");

            // Do the angle bracket song and dance:
            text = text.replace(/</g, "&lt;");
            text = text.replace(/>/g, "&gt;");

            // Now, escape characters that are magic in Markdown:
            text = escapeCharacters(text, "\*_{}[]\\", false);

            // jj the line above breaks this:
            //---

            //* Item

            //   1. Subitem

            //            special char: *
            //---

            return text;
        }

        function _DoItalicsAndBold(text) {

            // <strong> must go first:
            text = text.replace(/([\W_]|^)(\*\*|__)(?=\S)([^\r]*?\S[\*_]*)\2([\W_]|$)/g,
                "$1<strong>$3</strong>$4");

            text = text.replace(/([\W_]|^)(\*|_)(?=\S)([^\r\*_]*?\S)\2([\W_]|$)/g,
                "$1<em>$3</em>$4");

            return text;
        }

        function _DoBlockQuotes(text) {

            /*
             text = text.replace(/
             (                           // Wrap whole match in $1
             (
             ^[ \t]*>[ \t]?      // '>' at the start of a line
             .+\n                // rest of the first line
             (.+\n)*             // subsequent consecutive lines
             \n*                 // blanks
             )+
             )
             /gm, function(){...});
             */

            text = text.replace(/((^[ \t]*>[ \t]?.+\n(.+\n)*\n*)+)/gm,
                function (wholeMatch, m1) {
                    var bq = m1;

                    // attacklab: hack around Konqueror 3.5.4 bug:
                    // "----------bug".replace(/^-/g,"") == "bug"

                    bq = bq.replace(/^[ \t]*>[ \t]?/gm, "~0"); // trim one level of quoting

                    // attacklab: clean up hack
                    bq = bq.replace(/~0/g, "");

                    bq = bq.replace(/^[ \t]+$/gm, "");     // trim whitespace-only lines
                    bq = _RunBlockGamut(bq);             // recurse

                    bq = bq.replace(/(^|\n)/g, "$1  ");
                    // These leading spaces screw with <pre> content, so we need to fix that:
                    bq = bq.replace(
                        /(\s*<pre>[^\r]+?<\/pre>)/gm,
                        function (wholeMatch, m1) {
                            var pre = m1;
                            // attacklab: hack around Konqueror 3.5.4 bug:
                            pre = pre.replace(/^  /mg, "~0");
                            pre = pre.replace(/~0/g, "");
                            return pre;
                        });

                    return hashBlock("<blockquote>\n" + bq + "\n</blockquote>");
                }
            );
            return text;
        }

        function _FormParagraphs(text, doNotUnhash) {
            //
            //  Params:
            //    $text - string to process with html <p> tags
            //

            // Strip leading and trailing lines:
            text = text.replace(/^\n+/g, "");
            text = text.replace(/\n+$/g, "");

            var grafs = text.split(/\n{2,}/g);
            var grafsOut = [];

            var markerRe = /~K(\d+)K/;

            //
            // Wrap <p> tags.
            //
            var end = grafs.length;
            for (var i = 0; i < end; i++) {
                var str = grafs[i];

                // if this is an HTML marker, copy it
                if (markerRe.test(str)) {
                    grafsOut.push(str);
                }
                else if (/\S/.test(str)) {
                    str = _RunSpanGamut(str);
                    str = str.replace(/^([ \t]*)/g, "<p>");
                    str += "</p>"
                    grafsOut.push(str);
                }

            }
            //
            // Unhashify HTML blocks
            //
            if (!doNotUnhash) {
                end = grafsOut.length;
                for (var i = 0; i < end; i++) {
                    var foundAny = true;
                    while (foundAny) { // we may need several runs, since the data may be nested
                        foundAny = false;
                        grafsOut[i] = grafsOut[i].replace(/~K(\d+)K/g, function (wholeMatch, id) {
                            foundAny = true;
                            return g_html_blocks[id];
                        });
                    }
                }
            }
            return grafsOut.join("\n\n");
        }

        function _EncodeAmpsAndAngles(text) {
            // Smart processing for ampersands and angle brackets that need to be encoded.

            // Ampersand-encoding based entirely on Nat Irons's Amputator MT plugin:
            //   http://bumppo.net/projects/amputator/
            text = text.replace(/&(?!#?[xX]?(?:[0-9a-fA-F]+|\w+);)/g, "&amp;");

            // Encode naked <'s
            text = text.replace(/<(?![a-z\/?\$!])/gi, "&lt;");

            return text;
        }

        function _EncodeBackslashEscapes(text) {
            //
            //   Parameter:  String.
            //   Returns:    The string, with after processing the following backslash
            //               escape sequences.
            //

            // attacklab: The polite way to do this is with the new
            // escapeCharacters() function:
            //
            //     text = escapeCharacters(text,"\\",true);
            //     text = escapeCharacters(text,"`*_{}[]()>#+-.!",true);
            //
            // ...but we're sidestepping its use of the (slow) RegExp constructor
            // as an optimization for Firefox.  This function gets called a LOT.

            text = text.replace(/\\(\\)/g, escapeCharacters_callback);
            text = text.replace(/\\([`*_{}\[\]()>#+-.!])/g, escapeCharacters_callback);
            return text;
        }

        function _DoAutoLinks(text) {

            // note that at this point, all other URL in the text are already hyperlinked as <a href=""></a>
            // *except* for the <http://www.foo.com> case

            // automatically add < and > around unadorned raw hyperlinks
            // must be preceded by space/BOF and followed by non-word/EOF character
            text = text.replace(/(^|\s)(https?|ftp)(:\/\/[-A-Z0-9+&@#\/%?=~_|\[\]\(\)!:,\.;]*[-A-Z0-9+&@#\/%=~_|\[\]])($|\W)/gi, "$1<$2$3>$4");

            //  autolink anything like <http://example.com>

            var replacer = function (wholematch, m1) { return "<a href=\"" + m1 + "\">" + pluginHooks.plainLinkText(m1) + "</a>"; }
            text = text.replace(/<((https?|ftp):[^'">\s]+)>/gi, replacer);

            // Email addresses: <address@domain.foo>
            /*
             text = text.replace(/
             <
             (?:mailto:)?
             (
             [-.\w]+
             \@
             [-a-z0-9]+(\.[-a-z0-9]+)*\.[a-z]+
             )
             >
             /gi, _DoAutoLinks_callback());
             */

            var email_replacer = function(wholematch, m1) {
                var mailto = 'mailto:'
                var link
                var email
                if (m1.substring(0, mailto.length) != mailto){
                    link = mailto + m1;
                    email = m1;
                } else {
                    link = m1;
                    email = m1.substring(mailto.length, m1.length);
                }
                return "<a href=\"" + link + "\">" + pluginHooks.plainLinkText(email) + "</a>";
            }
            text = text.replace(/<((?:mailto:)?([-.\w]+\@[-a-z0-9]+(\.[-a-z0-9]+)*\.[a-z]+))>/gi, email_replacer);

            return text;
        }

        function _UnescapeSpecialChars(text) {
            //
            // Swap back in all the special characters we've hidden.
            //
            text = text.replace(/~E(\d+)E/g,
                function (wholeMatch, m1) {
                    var charCodeToReplace = parseInt(m1);
                    return String.fromCharCode(charCodeToReplace);
                }
            );
            return text;
        }

        function _Outdent(text) {
            //
            // Remove one level of line-leading tabs or spaces
            //

            // attacklab: hack around Konqueror 3.5.4 bug:
            // "----------bug".replace(/^-/g,"") == "bug"

            text = text.replace(/^(\t|[ ]{1,4})/gm, "~0"); // attacklab: g_tab_width

            // attacklab: clean up hack
            text = text.replace(/~0/g, "")

            return text;
        }

        function _Detab(text) {
            if (!/\t/.test(text))
                return text;

            var spaces = ["    ", "   ", "  ", " "],
                skew = 0,
                v;

            return text.replace(/[\n\t]/g, function (match, offset) {
                if (match === "\n") {
                    skew = offset + 1;
                    return match;
                }
                v = (offset - skew) % 4;
                skew = offset + 1;
                return spaces[v];
            });
        }

        //
        //  attacklab: Utility functions
        //

        var _problemUrlChars = /(?:["'*()[\]:]|~D)/g;

        // hex-encodes some unusual "problem" chars in URLs to avoid URL detection problems
        function encodeProblemUrlChars(url) {
            if (!url)
                return "";

            var len = url.length;

            return url.replace(_problemUrlChars, function (match, offset) {
                if (match == "~D") // escape for dollar
                    return "%24";
                if (match == ":") {
                    if (offset == len - 1 || /[0-9\/]/.test(url.charAt(offset + 1)))
                        return ":";
                    if (url.substring(0, 'mailto:'.length) === 'mailto:')
                        return ":";
                    if (url.substring(0, 'magnet:'.length) === 'magnet:')
                        return ":";
                }
                return "%" + match.charCodeAt(0).toString(16);
            });
        }


        function escapeCharacters(text, charsToEscape, afterBackslash) {
            // First we have to escape the escape characters so that
            // we can build a character class out of them
            var regexString = "([" + charsToEscape.replace(/([\[\]\\])/g, "\\$1") + "])";

            if (afterBackslash) {
                regexString = "\\\\" + regexString;
            }

            var regex = new RegExp(regexString, "g");
            text = text.replace(regex, escapeCharacters_callback);

            return text;
        }


        function escapeCharacters_callback(wholeMatch, m1) {
            var charCodeToEscape = m1.charCodeAt(0);
            return "~E" + charCodeToEscape + "E";
        }

    }; // end of the Markdown.Converter constructor

})();

// needs Markdown.Converter.js at the moment

(function () {

    var util = {},
        position = {},
        ui = {},
        doc = window.document,
        re = window.RegExp,
        nav = window.navigator,
        SETTINGS = { lineLength: 72 },

    // Used to work around some browser bugs where we can't use feature testing.
        uaSniffed = {
            isIE: /msie/.test(nav.userAgent.toLowerCase()),
            isIE_5or6: /msie 6/.test(nav.userAgent.toLowerCase()) || /msie 5/.test(nav.userAgent.toLowerCase()),
            isOpera: /opera/.test(nav.userAgent.toLowerCase())
        };


    // -------------------------------------------------------------------
    //  YOUR CHANGES GO HERE
    //
    // I've tried to localize the things you are likely to change to
    // this area.
    // -------------------------------------------------------------------

    // The text that appears on the upper part of the dialog box when
    // entering links.
    var linkDialogText = "<code>http://example.com/ \"optional title\"</code>";
    var imageDialogText = "<code>http://example.com/images/diagram.jpg \"optional title\"</code>";

    // The default text that appears in the dialog input box when entering
    // links.
    var imageDefaultText = "http://";
    var linkDefaultText = "http://";

    var defaultHelpHoverTitle = "Markdown Editing Help";

    // -------------------------------------------------------------------
    //  END OF YOUR CHANGES
    // -------------------------------------------------------------------

    // help, if given, should have a property "handler", the click handler for the help button,
    // and can have an optional property "title" for the button's tooltip (defaults to "Markdown Editing Help").
    // If help isn't given, not help button is created.
    //
    // The constructed editor object has the methods:
    // - getConverter() returns the markdown converter object that was passed to the constructor
    // - run() actually starts the editor; should be called after all necessary plugins are registered. Calling this more than once is a no-op.
    // - refreshPreview() forces the preview to be updated. This method is only available after run() was called.
    Markdown.Editor = function (markdownConverter, idPostfix, help) {

        idPostfix = idPostfix || "";

        var hooks = this.hooks = new Markdown.HookCollection();
        hooks.addNoop("onPreviewRefresh");       // called with no arguments after the preview has been refreshed
        hooks.addNoop("postBlockquoteCreation"); // called with the user's selection *after* the blockquote was created; should return the actual to-be-inserted text
        hooks.addFalse("insertImageDialog");     /* called with one parameter: a callback to be called with the URL of the image. If the application creates
         * its own image insertion dialog, this hook should return true, and the callback should be called with the chosen
         * image url (or null if the user cancelled). If this hook returns false, the default dialog will be used.
         */

        this.getConverter = function () { return markdownConverter; }

        var that = this,
            panels;

        this.run = function () {
            if (panels)
                return; // already initialized

            panels = new PanelCollection(idPostfix);
            var commandManager = new CommandManager(hooks);
            var previewManager = new PreviewManager(markdownConverter, panels, function () { hooks.onPreviewRefresh(); });
            var undoManager, uiManager;

            if (!/\?noundo/.test(doc.location.href)) {
                undoManager = new UndoManager(function () {
                    previewManager.refresh();
                    if (uiManager) // not available on the first call
                        uiManager.setUndoRedoButtonStates();
                }, panels);
                this.textOperation = function (f) {
                    undoManager.setCommandMode();
                    f();
                    that.refreshPreview();
                }
            }

            uiManager = new UIManager(idPostfix, panels, undoManager, previewManager, commandManager, help);
            uiManager.setUndoRedoButtonStates();

            var forceRefresh = that.refreshPreview = function () { previewManager.refresh(true); };

            forceRefresh();
        };

    }

    // before: contains all the text in the input box BEFORE the selection.
    // after: contains all the text in the input box AFTER the selection.
    function Chunks() { }

    // startRegex: a regular expression to find the start tag
    // endRegex: a regular expresssion to find the end tag
    Chunks.prototype.findTags = function (startRegex, endRegex) {

        var chunkObj = this;
        var regex;

        if (startRegex) {

            regex = util.extendRegExp(startRegex, "", "$");

            this.before = this.before.replace(regex,
                function (match) {
                    chunkObj.startTag = chunkObj.startTag + match;
                    return "";
                });

            regex = util.extendRegExp(startRegex, "^", "");

            this.selection = this.selection.replace(regex,
                function (match) {
                    chunkObj.startTag = chunkObj.startTag + match;
                    return "";
                });
        }

        if (endRegex) {

            regex = util.extendRegExp(endRegex, "", "$");

            this.selection = this.selection.replace(regex,
                function (match) {
                    chunkObj.endTag = match + chunkObj.endTag;
                    return "";
                });

            regex = util.extendRegExp(endRegex, "^", "");

            this.after = this.after.replace(regex,
                function (match) {
                    chunkObj.endTag = match + chunkObj.endTag;
                    return "";
                });
        }
    };

    // If remove is false, the whitespace is transferred
    // to the before/after regions.
    //
    // If remove is true, the whitespace disappears.
    Chunks.prototype.trimWhitespace = function (remove) {
        var beforeReplacer, afterReplacer, that = this;
        if (remove) {
            beforeReplacer = afterReplacer = "";
        } else {
            beforeReplacer = function (s) { that.before += s; return ""; }
            afterReplacer = function (s) { that.after = s + that.after; return ""; }
        }

        this.selection = this.selection.replace(/^(\s*)/, beforeReplacer).replace(/(\s*)$/, afterReplacer);
    };


    Chunks.prototype.skipLines = function (nLinesBefore, nLinesAfter, findExtraNewlines) {

        if (nLinesBefore === undefined) {
            nLinesBefore = 1;
        }

        if (nLinesAfter === undefined) {
            nLinesAfter = 1;
        }

        nLinesBefore++;
        nLinesAfter++;

        var regexText;
        var replacementText;

        // chrome bug ... documented at: http://meta.stackoverflow.com/questions/63307/blockquote-glitch-in-editor-in-chrome-6-and-7/65985#65985
        if (navigator.userAgent.match(/Chrome/)) {
            "X".match(/()./);
        }

        this.selection = this.selection.replace(/(^\n*)/, "");

        this.startTag = this.startTag + re.$1;

        this.selection = this.selection.replace(/(\n*$)/, "");
        this.endTag = this.endTag + re.$1;
        this.startTag = this.startTag.replace(/(^\n*)/, "");
        this.before = this.before + re.$1;
        this.endTag = this.endTag.replace(/(\n*$)/, "");
        this.after = this.after + re.$1;

        if (this.before) {

            regexText = replacementText = "";

            while (nLinesBefore--) {
                regexText += "\\n?";
                replacementText += "\n";
            }

            if (findExtraNewlines) {
                regexText = "\\n*";
            }
            this.before = this.before.replace(new re(regexText + "$", ""), replacementText);
        }

        if (this.after) {

            regexText = replacementText = "";

            while (nLinesAfter--) {
                regexText += "\\n?";
                replacementText += "\n";
            }
            if (findExtraNewlines) {
                regexText = "\\n*";
            }

            this.after = this.after.replace(new re(regexText, ""), replacementText);
        }
    };

    // end of Chunks

    // A collection of the important regions on the page.
    // Cached so we don't have to keep traversing the DOM.
    // Also holds ieCachedRange and ieCachedScrollTop, where necessary; working around
    // this issue:
    // Internet explorer has problems with CSS sprite buttons that use HTML
    // lists.  When you click on the background image "button", IE will
    // select the non-existent link text and discard the selection in the
    // textarea.  The solution to this is to cache the textarea selection
    // on the button's mousedown event and set a flag.  In the part of the
    // code where we need to grab the selection, we check for the flag
    // and, if it's set, use the cached area instead of querying the
    // textarea.
    //
    // This ONLY affects Internet Explorer (tested on versions 6, 7
    // and 8) and ONLY on button clicks.  Keyboard shortcuts work
    // normally since the focus never leaves the textarea.
    function PanelCollection(postfix) {
        this.buttonBar = doc.getElementById("wmd-button-bar" + postfix);
        this.preview = doc.getElementById("wmd-preview" + postfix);
        this.input = doc.getElementById("wmd-input" + postfix);
    };

    // Returns true if the DOM element is visible, false if it's hidden.
    // Checks if display is anything other than none.
    util.isVisible = function (elem) {

        if (window.getComputedStyle) {
            // Most browsers
            return window.getComputedStyle(elem, null).getPropertyValue("display") !== "none";
        }
        else if (elem.currentStyle) {
            // IE
            return elem.currentStyle["display"] !== "none";
        }
    };


    // Adds a listener callback to a DOM element which is fired on a specified
    // event.
    util.addEvent = function (elem, event, listener) {
        if (elem.attachEvent) {
            // IE only.  The "on" is mandatory.
            elem.attachEvent("on" + event, listener);
        }
        else {
            // Other browsers.
            elem.addEventListener(event, listener, false);
        }
    };


    // Removes a listener callback from a DOM element which is fired on a specified
    // event.
    util.removeEvent = function (elem, event, listener) {
        if (elem.detachEvent) {
            // IE only.  The "on" is mandatory.
            elem.detachEvent("on" + event, listener);
        }
        else {
            // Other browsers.
            elem.removeEventListener(event, listener, false);
        }
    };

    // Converts \r\n and \r to \n.
    util.fixEolChars = function (text) {
        text = text.replace(/\r\n/g, "\n");
        text = text.replace(/\r/g, "\n");
        return text;
    };

    // Extends a regular expression.  Returns a new RegExp
    // using pre + regex + post as the expression.
    // Used in a few functions where we have a base
    // expression and we want to pre- or append some
    // conditions to it (e.g. adding "$" to the end).
    // The flags are unchanged.
    //
    // regex is a RegExp, pre and post are strings.
    util.extendRegExp = function (regex, pre, post) {

        if (pre === null || pre === undefined) {
            pre = "";
        }
        if (post === null || post === undefined) {
            post = "";
        }

        var pattern = regex.toString();
        var flags;

        // Replace the flags with empty space and store them.
        pattern = pattern.replace(/\/([gim]*)$/, function (wholeMatch, flagsPart) {
            flags = flagsPart;
            return "";
        });

        // Remove the slash delimiters on the regular expression.
        pattern = pattern.replace(/(^\/|\/$)/g, "");
        pattern = pre + pattern + post;

        return new re(pattern, flags);
    }

    // UNFINISHED
    // The assignment in the while loop makes jslint cranky.
    // I'll change it to a better loop later.
    position.getTop = function (elem, isInner) {
        var result = elem.offsetTop;
        if (!isInner) {
            while (elem = elem.offsetParent) {
                result += elem.offsetTop;
            }
        }
        return result;
    };

    position.getHeight = function (elem) {
        return elem.offsetHeight || elem.scrollHeight;
    };

    position.getWidth = function (elem) {
        return elem.offsetWidth || elem.scrollWidth;
    };

    position.getPageSize = function () {

        var scrollWidth, scrollHeight;
        var innerWidth, innerHeight;

        // It's not very clear which blocks work with which browsers.
        if (self.innerHeight && self.scrollMaxY) {
            scrollWidth = doc.body.scrollWidth;
            scrollHeight = self.innerHeight + self.scrollMaxY;
        }
        else if (doc.body.scrollHeight > doc.body.offsetHeight) {
            scrollWidth = doc.body.scrollWidth;
            scrollHeight = doc.body.scrollHeight;
        }
        else {
            scrollWidth = doc.body.offsetWidth;
            scrollHeight = doc.body.offsetHeight;
        }

        if (self.innerHeight) {
            // Non-IE browser
            innerWidth = self.innerWidth;
            innerHeight = self.innerHeight;
        }
        else if (doc.documentElement && doc.documentElement.clientHeight) {
            // Some versions of IE (IE 6 w/ a DOCTYPE declaration)
            innerWidth = doc.documentElement.clientWidth;
            innerHeight = doc.documentElement.clientHeight;
        }
        else if (doc.body) {
            // Other versions of IE
            innerWidth = doc.body.clientWidth;
            innerHeight = doc.body.clientHeight;
        }

        var maxWidth = Math.max(scrollWidth, innerWidth);
        var maxHeight = Math.max(scrollHeight, innerHeight);
        return [maxWidth, maxHeight, innerWidth, innerHeight];
    };

    // Handles pushing and popping TextareaStates for undo/redo commands.
    // I should rename the stack variables to list.
    function UndoManager(callback, panels) {

        var undoObj = this;
        var undoStack = []; // A stack of undo states
        var stackPtr = 0; // The index of the current state
        var mode = "none";
        var lastState; // The last state
        var timer; // The setTimeout handle for cancelling the timer
        var inputStateObj;

        // Set the mode for later logic steps.
        var setMode = function (newMode, noSave) {
            if (mode != newMode) {
                mode = newMode;
                if (!noSave) {
                    saveState();
                }
            }

            if (!uaSniffed.isIE || mode != "moving") {
                timer = setTimeout(refreshState, 1);
            }
            else {
                inputStateObj = null;
            }
        };

        var refreshState = function (isInitialState) {
            inputStateObj = new TextareaState(panels, isInitialState);
            timer = undefined;
        };

        this.setCommandMode = function () {
            mode = "command";
            saveState();
            timer = setTimeout(refreshState, 0);
        };

        this.canUndo = function () {
            return stackPtr > 1;
        };

        this.canRedo = function () {
            if (undoStack[stackPtr + 1]) {
                return true;
            }
            return false;
        };

        // Removes the last state and restores it.
        this.undo = function () {

            if (undoObj.canUndo()) {
                if (lastState) {
                    // What about setting state -1 to null or checking for undefined?
                    lastState.restore();
                    lastState = null;
                }
                else {
                    undoStack[stackPtr] = new TextareaState(panels);
                    undoStack[--stackPtr].restore();

                    if (callback) {
                        callback();
                    }
                }
            }

            mode = "none";
            panels.input.focus();
            refreshState();
        };

        // Redo an action.
        this.redo = function () {

            if (undoObj.canRedo()) {

                undoStack[++stackPtr].restore();

                if (callback) {
                    callback();
                }
            }

            mode = "none";
            panels.input.focus();
            refreshState();
        };

        // Push the input area state to the stack.
        var saveState = function () {
            var currState = inputStateObj || new TextareaState(panels);

            if (!currState) {
                return false;
            }
            if (mode == "moving") {
                if (!lastState) {
                    lastState = currState;
                }
                return;
            }
            if (lastState) {
                if (undoStack[stackPtr - 1].text != lastState.text) {
                    undoStack[stackPtr++] = lastState;
                }
                lastState = null;
            }
            undoStack[stackPtr++] = currState;
            undoStack[stackPtr + 1] = null;
            if (callback) {
                callback();
            }
        };

        var handleCtrlYZ = function (event) {

            var handled = false;

            if (event.ctrlKey || event.metaKey) {

                // IE and Opera do not support charCode.
                var keyCode = event.charCode || event.keyCode;
                var keyCodeChar = String.fromCharCode(keyCode);

                switch (keyCodeChar) {

                    case "y":
                        undoObj.redo();
                        handled = true;
                        break;

                    case "z":
                        if (!event.shiftKey) {
                            undoObj.undo();
                        }
                        else {
                            undoObj.redo();
                        }
                        handled = true;
                        break;
                }
            }

            if (handled) {
                if (event.preventDefault) {
                    event.preventDefault();
                }
                if (window.event) {
                    window.event.returnValue = false;
                }
                return;
            }
        };

        // Set the mode depending on what is going on in the input area.
        var handleModeChange = function (event) {

            if (!event.ctrlKey && !event.metaKey) {

                var keyCode = event.keyCode;

                if ((keyCode >= 33 && keyCode <= 40) || (keyCode >= 63232 && keyCode <= 63235)) {
                    // 33 - 40: page up/dn and arrow keys
                    // 63232 - 63235: page up/dn and arrow keys on safari
                    setMode("moving");
                }
                else if (keyCode == 8 || keyCode == 46 || keyCode == 127) {
                    // 8: backspace
                    // 46: delete
                    // 127: delete
                    setMode("deleting");
                }
                else if (keyCode == 13) {
                    // 13: Enter
                    setMode("newlines");
                }
                else if (keyCode == 27) {
                    // 27: escape
                    setMode("escape");
                }
                else if ((keyCode < 16 || keyCode > 20) && keyCode != 91) {
                    // 16-20 are shift, etc.
                    // 91: left window key
                    // I think this might be a little messed up since there are
                    // a lot of nonprinting keys above 20.
                    setMode("typing");
                }
            }
        };

        var setEventHandlers = function () {
            util.addEvent(panels.input, "keypress", function (event) {
                // keyCode 89: y
                // keyCode 90: z
                if ((event.ctrlKey || event.metaKey) && (event.keyCode == 89 || event.keyCode == 90)) {
                    event.preventDefault();
                }
            });

            var handlePaste = function () {
                if (uaSniffed.isIE || (inputStateObj && inputStateObj.text != panels.input.value)) {
                    if (timer == undefined) {
                        mode = "paste";
                        saveState();
                        refreshState();
                    }
                }
            };

            util.addEvent(panels.input, "keydown", handleCtrlYZ);
            util.addEvent(panels.input, "keydown", handleModeChange);
            util.addEvent(panels.input, "mousedown", function () {
                setMode("moving");
            });

            panels.input.onpaste = handlePaste;
            panels.input.ondrop = handlePaste;
        };

        var init = function () {
            setEventHandlers();
            refreshState(true);
            saveState();
        };

        init();
    }

    // end of UndoManager

    // The input textarea state/contents.
    // This is used to implement undo/redo by the undo manager.
    function TextareaState(panels, isInitialState) {

        // Aliases
        var stateObj = this;
        var inputArea = panels.input;
        this.init = function () {
            if (!util.isVisible(inputArea)) {
                return;
            }
            if (!isInitialState && doc.activeElement && doc.activeElement !== inputArea) { // this happens when tabbing out of the input box
                return;
            }

            this.setInputAreaSelectionStartEnd();
            this.scrollTop = inputArea.scrollTop;
            if (!this.text && inputArea.selectionStart || inputArea.selectionStart === 0) {
                this.text = inputArea.value;
            }

        }

        // Sets the selected text in the input box after we've performed an
        // operation.
        this.setInputAreaSelection = function () {

            if (!util.isVisible(inputArea)) {
                return;
            }

            if (inputArea.selectionStart !== undefined && !uaSniffed.isOpera) {

                inputArea.focus();
                inputArea.selectionStart = stateObj.start;
                inputArea.selectionEnd = stateObj.end;
                inputArea.scrollTop = stateObj.scrollTop;
            }
            else if (doc.selection) {

                if (doc.activeElement && doc.activeElement !== inputArea) {
                    return;
                }

                inputArea.focus();
                var range = inputArea.createTextRange();
                range.moveStart("character", -inputArea.value.length);
                range.moveEnd("character", -inputArea.value.length);
                range.moveEnd("character", stateObj.end);
                range.moveStart("character", stateObj.start);
                range.select();
            }
        };

        this.setInputAreaSelectionStartEnd = function () {

            if (!panels.ieCachedRange && (inputArea.selectionStart || inputArea.selectionStart === 0)) {

                stateObj.start = inputArea.selectionStart;
                stateObj.end = inputArea.selectionEnd;
            }
            else if (doc.selection) {

                stateObj.text = util.fixEolChars(inputArea.value);

                // IE loses the selection in the textarea when buttons are
                // clicked.  On IE we cache the selection. Here, if something is cached,
                // we take it.
                var range = panels.ieCachedRange || doc.selection.createRange();

                var fixedRange = util.fixEolChars(range.text);
                var marker = "\x07";
                var markedRange = marker + fixedRange + marker;
                range.text = markedRange;
                var inputText = util.fixEolChars(inputArea.value);

                range.moveStart("character", -markedRange.length);
                range.text = fixedRange;

                stateObj.start = inputText.indexOf(marker);
                stateObj.end = inputText.lastIndexOf(marker) - marker.length;

                var len = stateObj.text.length - util.fixEolChars(inputArea.value).length;

                if (len) {
                    range.moveStart("character", -fixedRange.length);
                    while (len--) {
                        fixedRange += "\n";
                        stateObj.end += 1;
                    }
                    range.text = fixedRange;
                }

                if (panels.ieCachedRange)
                    stateObj.scrollTop = panels.ieCachedScrollTop; // this is set alongside with ieCachedRange

                panels.ieCachedRange = null;

                this.setInputAreaSelection();
            }
        };

        // Restore this state into the input area.
        this.restore = function () {

            if (stateObj.text != undefined && stateObj.text != inputArea.value) {
                inputArea.value = stateObj.text;
            }
            this.setInputAreaSelection();
            inputArea.scrollTop = stateObj.scrollTop;
        };

        // Gets a collection of HTML chunks from the inptut textarea.
        this.getChunks = function () {

            var chunk = new Chunks();
            chunk.before = util.fixEolChars(stateObj.text.substring(0, stateObj.start));
            chunk.startTag = "";
            chunk.selection = util.fixEolChars(stateObj.text.substring(stateObj.start, stateObj.end));
            chunk.endTag = "";
            chunk.after = util.fixEolChars(stateObj.text.substring(stateObj.end));
            chunk.scrollTop = stateObj.scrollTop;

            return chunk;
        };

        // Sets the TextareaState properties given a chunk of markdown.
        this.setChunks = function (chunk) {

            chunk.before = chunk.before + chunk.startTag;
            chunk.after = chunk.endTag + chunk.after;

            this.start = chunk.before.length;
            this.end = chunk.before.length + chunk.selection.length;
            this.text = chunk.before + chunk.selection + chunk.after;
            this.scrollTop = chunk.scrollTop;
        };
        this.init();
    };

    function PreviewManager(converter, panels, previewRefreshCallback) {

        var managerObj = this;
        var timeout;
        var elapsedTime;
        var oldInputText;
        var maxDelay = 3000;
        var startType = "delayed"; // The other legal value is "manual"

        // Adds event listeners to elements
        var setupEvents = function (inputElem, listener) {

            util.addEvent(inputElem, "input", listener);
            inputElem.onpaste = listener;
            inputElem.ondrop = listener;

            util.addEvent(inputElem, "keypress", listener);
            util.addEvent(inputElem, "keydown", listener);
        };

        var getDocScrollTop = function () {

            var result = 0;

            if (window.innerHeight) {
                result = window.pageYOffset;
            }
            else
            if (doc.documentElement && doc.documentElement.scrollTop) {
                result = doc.documentElement.scrollTop;
            }
            else
            if (doc.body) {
                result = doc.body.scrollTop;
            }

            return result;
        };

        var makePreviewHtml = function () {

            // If there is no registered preview panel
            // there is nothing to do.
            if (!panels.preview)
                return;


            var text = panels.input.value;
            if (text && text == oldInputText) {
                return; // Input text hasn't changed.
            }
            else {
                oldInputText = text;
            }

            var prevTime = new Date().getTime();

            text = converter.makeHtml(text);

            // Calculate the processing time of the HTML creation.
            // It's used as the delay time in the event listener.
            var currTime = new Date().getTime();
            elapsedTime = currTime - prevTime;

            pushPreviewHtml(text);
        };

        // setTimeout is already used.  Used as an event listener.
        var applyTimeout = function () {

            if (timeout) {
                clearTimeout(timeout);
                timeout = undefined;
            }

            if (startType !== "manual") {

                var delay = 0;

                if (startType === "delayed") {
                    delay = elapsedTime;
                }

                if (delay > maxDelay) {
                    delay = maxDelay;
                }
                timeout = setTimeout(makePreviewHtml, delay);
            }
        };

        var getScaleFactor = function (panel) {
            if (panel.scrollHeight <= panel.clientHeight) {
                return 1;
            }
            return panel.scrollTop / (panel.scrollHeight - panel.clientHeight);
        };

        var setPanelScrollTops = function () {
            if (panels.preview) {
                panels.preview.scrollTop = (panels.preview.scrollHeight - panels.preview.clientHeight) * getScaleFactor(panels.preview);
            }
        };

        this.refresh = function (requiresRefresh) {

            if (requiresRefresh) {
                oldInputText = "";
                makePreviewHtml();
            }
            else {
                applyTimeout();
            }
        };

        this.processingTime = function () {
            return elapsedTime;
        };

        var isFirstTimeFilled = true;

        // IE doesn't let you use innerHTML if the element is contained somewhere in a table
        // (which is the case for inline editing) -- in that case, detach the element, set the
        // value, and reattach. Yes, that *is* ridiculous.
        var ieSafePreviewSet = function (text) {
            var preview = panels.preview;
            var parent = preview.parentNode;
            var sibling = preview.nextSibling;
            parent.removeChild(preview);
            preview.innerHTML = text;
            if (!sibling)
                parent.appendChild(preview);
            else
                parent.insertBefore(preview, sibling);
        }

        var nonSuckyBrowserPreviewSet = function (text) {
            panels.preview.innerHTML = text;
        }

        var previewSetter;

        var previewSet = function (text) {
            if (previewSetter)
                return previewSetter(text);

            try {
                nonSuckyBrowserPreviewSet(text);
                previewSetter = nonSuckyBrowserPreviewSet;
            } catch (e) {
                previewSetter = ieSafePreviewSet;
                previewSetter(text);
            }
        };

        var pushPreviewHtml = function (text) {

            var emptyTop = position.getTop(panels.input) - getDocScrollTop();

            if (panels.preview) {
                previewSet(text);
                previewRefreshCallback();
            }

            setPanelScrollTops();

            if (isFirstTimeFilled) {
                isFirstTimeFilled = false;
                return;
            }

            var fullTop = position.getTop(panels.input) - getDocScrollTop();

            if (uaSniffed.isIE) {
                setTimeout(function () {
                    window.scrollBy(0, fullTop - emptyTop);
                }, 0);
            }
            else {
                window.scrollBy(0, fullTop - emptyTop);
            }
        };

        var init = function () {

            setupEvents(panels.input, applyTimeout);
            makePreviewHtml();

            if (panels.preview) {
                panels.preview.scrollTop = 0;
            }
        };

        init();
    };


    // This simulates a modal dialog box and asks for the URL when you
    // click the hyperlink or image buttons.
    //
    // text: The html for the input box.
    // defaultInputText: The default value that appears in the input box.
    // callback: The function which is executed when the prompt is dismissed, either via OK or Cancel.
    //      It receives a single argument; either the entered text (if OK was chosen) or null (if Cancel
    //      was chosen).
    ui.prompt = function (title, text, defaultInputText, callback) {

        // These variables need to be declared at this level since they are used
        // in multiple functions.
        var dialog;         // The dialog box.
        var input;         // The text box where you enter the hyperlink.


        if (defaultInputText === undefined) {
            defaultInputText = "";
        }

        // Used as a keydown event handler. Esc dismisses the prompt.
        // Key code 27 is ESC.
        var checkEscape = function (key) {
            var code = (key.charCode || key.keyCode);
            if (code === 27) {
                close(true);
            }
        };

        // Dismisses the hyperlink input box.
        // isCancel is true if we don't care about the input text.
        // isCancel is false if we are going to keep the text.
        var close = function (isCancel) {
            util.removeEvent(doc.body, "keydown", checkEscape);
            var text = input.value;

            if (isCancel) {
                text = null;
            }
            else {
                // Fixes common pasting errors.
                text = text.replace(/^http:\/\/(https?|ftp):\/\//, '$1://');
                if (!/^(?:https?|ftp):\/\//.test(text))
                    text = 'http://' + text;
            }

            $(dialog).modal('hide');

            callback(text);
            return false;
        };



        // Create the text input box form/window.
        var createDialog = function () {
            // <div class="modal" id="myModal">
            //   <div class="modal-header">
            //     <a class="close" data-dismiss="modal">Ã—</a>
            //     <h3>Modal header</h3>
            //   </div>
            //   <div class="modal-body">
            //     <p>One fine bodyâ€¦</p>
            //   </div>
            //   <div class="modal-footer">
            //     <a href="#" class="btn btn-primary">Save changes</a>
            //     <a href="#" class="btn">Close</a>
            //   </div>
            // </div>

            // The main dialog box.
            dialog = doc.createElement("div");
            dialog.className = "modal fade";

            // The modal-dialog div.
            var div_dialog = doc.createElement("div");
            div_dialog.className = "modal-dialog";
            dialog.appendChild(div_dialog);

            // The modal-content div.
            var content = doc.createElement("div");
            content.className = "modal-content";
            div_dialog.appendChild(content);

            // The header.
            var header = doc.createElement("div");
            header.className = "modal-header";
            header.innerHTML = '<a class="close" data-dismiss="modal">Ã—</a> <h3 class="modal-title">'+title+'</h3>';
            content.appendChild(header);

            // The body.
            var body = doc.createElement("div");
            body.className = "modal-body";
            content.appendChild(body);

            // The footer.
            var footer = doc.createElement("div");
            footer.className = "modal-footer";
            content.appendChild(footer);

            // The dialog text.
            var question = doc.createElement("p");
            question.innerHTML = text;
            question.style.padding = "5px";
            body.appendChild(question);

            // The web form container for the text box and buttons.
            var form = doc.createElement("form"),
                style = form.style;
            form.onsubmit = function () { return close(false); };
            style.padding = "0";
            style.margin = "0";
            body.appendChild(form);

            // The input text box
            input = doc.createElement("input");
            input.type = "text";
            input.value = defaultInputText;
            input.className = "form-control";
            style = input.style;
            style.display = "block";
            style.width = "80%";
            style.marginLeft = style.marginRight = "auto";
            form.appendChild(input);

            // The ok button
            var okButton = doc.createElement("button");
            okButton.className = "btn btn-primary";
            okButton.type = "button";
            okButton.onclick = function () { return close(false); };
            okButton.innerHTML = "OK";

            // The cancel button
            var cancelButton = doc.createElement("button");
            cancelButton.className = "btn btn-danger";
            cancelButton.type = "button";
            cancelButton.onclick = function () { return close(true); };
            cancelButton.innerHTML = "Cancel";

            footer.appendChild(okButton);
            footer.appendChild(cancelButton);

            util.addEvent(doc.body, "keydown", checkEscape);

            doc.body.appendChild(dialog);

        };

        // Why is this in a zero-length timeout?
        // Is it working around a browser bug?
        setTimeout(function () {

            createDialog();

            var defTextLen = defaultInputText.length;
            if (input.selectionStart !== undefined) {
                input.selectionStart = 0;
                input.selectionEnd = defTextLen;
            }
            else if (input.createTextRange) {
                var range = input.createTextRange();
                range.collapse(false);
                range.moveStart("character", -defTextLen);
                range.moveEnd("character", defTextLen);
                range.select();
            }

            $(dialog).on('shown', function () {
                input.focus();
            })

            $(dialog).on('hidden', function () {
                dialog.parentNode.removeChild(dialog);
            })

            $(dialog).modal()

        }, 0);
    };

    function UIManager(postfix, panels, undoManager, previewManager, commandManager, helpOptions) {

        var inputBox = panels.input,
            buttons = {}; // buttons.undo, buttons.link, etc. The actual DOM elements.

        makeSpritedButtonRow();

        var keyEvent = "keydown";
        if (uaSniffed.isOpera) {
            keyEvent = "keypress";
        }

        util.addEvent(inputBox, keyEvent, function (key) {

            // Check to see if we have a button key and, if so execute the callback.
            if ((key.ctrlKey || key.metaKey) && !key.altKey && !key.shiftKey) {

                var keyCode = key.charCode || key.keyCode;
                var keyCodeStr = String.fromCharCode(keyCode).toLowerCase();

                switch (keyCodeStr) {
                    case "b":
                        doClick(buttons.bold);
                        break;
                    case "i":
                        doClick(buttons.italic);
                        break;
                    case "l":
                        doClick(buttons.link);
                        break;
                    case "q":
                        doClick(buttons.quote);
                        break;
                    case "k":
                        doClick(buttons.code);
                        break;
                    case "g":
                        doClick(buttons.image);
                        break;
                    case "o":
                        doClick(buttons.olist);
                        break;
                    case "u":
                        doClick(buttons.ulist);
                        break;
                    case "h":
                        doClick(buttons.heading);
                        break;
                    case "r":
                        doClick(buttons.hr);
                        break;
                    case "y":
                        doClick(buttons.redo);
                        break;
                    case "z":
                        if (key.shiftKey) {
                            doClick(buttons.redo);
                        }
                        else {
                            doClick(buttons.undo);
                        }
                        break;
                    default:
                        return;
                }


                if (key.preventDefault) {
                    key.preventDefault();
                }

                if (window.event) {
                    window.event.returnValue = false;
                }
            }
        });

        // Auto-indent on shift-enter
        util.addEvent(inputBox, "keyup", function (key) {
            if (key.shiftKey && !key.ctrlKey && !key.metaKey) {
                var keyCode = key.charCode || key.keyCode;
                // Character 13 is Enter
                if (keyCode === 13) {
                    var fakeButton = {};
                    fakeButton.textOp = bindCommand("doAutoindent");
                    doClick(fakeButton);
                }
            }
        });

        // special handler because IE clears the context of the textbox on ESC
        if (uaSniffed.isIE) {
            util.addEvent(inputBox, "keydown", function (key) {
                var code = key.keyCode;
                if (code === 27) {
                    return false;
                }
            });
        }


        // Perform the button's action.
        function doClick(button) {

            inputBox.focus();

            if (button.textOp) {

                if (undoManager) {
                    undoManager.setCommandMode();
                }

                var state = new TextareaState(panels);

                if (!state) {
                    return;
                }

                var chunks = state.getChunks();

                // Some commands launch a "modal" prompt dialog.  Javascript
                // can't really make a modal dialog box and the WMD code
                // will continue to execute while the dialog is displayed.
                // This prevents the dialog pattern I'm used to and means
                // I can't do something like this:
                //
                // var link = CreateLinkDialog();
                // makeMarkdownLink(link);
                //
                // Instead of this straightforward method of handling a
                // dialog I have to pass any code which would execute
                // after the dialog is dismissed (e.g. link creation)
                // in a function parameter.
                //
                // Yes this is awkward and I think it sucks, but there's
                // no real workaround.  Only the image and link code
                // create dialogs and require the function pointers.
                var fixupInputArea = function () {

                    inputBox.focus();

                    if (chunks) {
                        state.setChunks(chunks);
                    }

                    state.restore();
                    previewManager.refresh();
                };

                var noCleanup = button.textOp(chunks, fixupInputArea);

                if (!noCleanup) {
                    fixupInputArea();
                }

            }

            if (button.execute) {
                button.execute(undoManager);
            }
        };

        function setupButton(button, isEnabled) {

            if (isEnabled) {
                button.disabled = false;

                if (!button.isHelp) {
                    button.onclick = function () {
                        if (this.onmouseout) {
                            this.onmouseout();
                        }
                        doClick(this);
                        return false;
                    }
                }
            }
            else {
                button.disabled = true;
            }
        }

        function bindCommand(method) {
            if (typeof method === "string")
                method = commandManager[method];
            return function () { method.apply(commandManager, arguments); }
        }

        function makeSpritedButtonRow() {

            var buttonBar = panels.buttonBar;
            var buttonRow = document.createElement("div");
            buttonRow.id = "wmd-button-row" + postfix;
            buttonRow.className = 'btn-toolbar';
            buttonRow = buttonBar.appendChild(buttonRow);

            var makeButton = function (id, title, icon, textOp, group) {
                var button = document.createElement("button");
                button.className = "btn btn-default";
                var buttonImage = document.createElement("i");
                buttonImage.className = icon;
                button.id = id + postfix;
                button.appendChild(buttonImage);
                button.title = title;
                $(button).tooltip({placement: 'bottom', container: 'body'})
                if (textOp)
                    button.textOp = textOp;
                setupButton(button, true);
                if (group) {
                    group.appendChild(button);
                } else {
                    buttonRow.appendChild(button);
                }
                return button;
            };
            var makeGroup = function (num) {
                var group = document.createElement("div");
                group.className = "btn-group wmd-button-group" + num;
                group.id = "wmd-button-group" + num + postfix;
                buttonRow.appendChild(group);
                return group
            }

            group1 = makeGroup(1);
            buttons.bold = makeButton("wmd-bold-button", "Bold - Ctrl+B", "glyph-icon icon-bold", bindCommand("doBold"), group1);
            buttons.italic = makeButton("wmd-italic-button", "Italic - Ctrl+I", "glyph-icon icon-italic", bindCommand("doItalic"), group1);

            group2 = makeGroup(2);
            buttons.link = makeButton("wmd-link-button", "Link - Ctrl+L", "glyph-icon icon-link", bindCommand(function (chunk, postProcessing) {
                return this.doLinkOrImage(chunk, postProcessing, false);
            }), group2);
            buttons.quote = makeButton("wmd-quote-button", "Blockquote - Ctrl+Q", "glyph-icon icon-quote-left", bindCommand("doBlockquote"), group2);
            buttons.code = makeButton("wmd-code-button", "Code Sample - Ctrl+K", "glyph-icon icon-code", bindCommand("doCode"), group2);
            buttons.image = makeButton("wmd-image-button", "Image - Ctrl+G", "glyph-icon icon-picture-o", bindCommand(function (chunk, postProcessing) {
                return this.doLinkOrImage(chunk, postProcessing, true);
            }), group2);

            group3 = makeGroup(3);
            buttons.olist = makeButton("wmd-olist-button", "Numbered List - Ctrl+O", "glyph-icon icon-list-ol", bindCommand(function (chunk, postProcessing) {
                this.doList(chunk, postProcessing, true);
            }), group3);
            buttons.ulist = makeButton("wmd-ulist-button", "Bulleted List - Ctrl+U", "glyph-icon icon-list-ul", bindCommand(function (chunk, postProcessing) {
                this.doList(chunk, postProcessing, false);
            }), group3);
            buttons.heading = makeButton("wmd-heading-button", "Heading - Ctrl+H", "glyph-icon icon-header", bindCommand("doHeading"), group3);
            buttons.hr = makeButton("wmd-hr-button", "Horizontal Rule - Ctrl+R", "glyph-icon icon-ellipsis-h", bindCommand("doHorizontalRule"), group3);

            group4 = makeGroup(4);
            buttons.undo = makeButton("wmd-undo-button", "Undo - Ctrl+Z", "glyph-icon icon-undo", null, group4);
            buttons.undo.execute = function (manager) { if (manager) manager.undo(); };

            var redoTitle = /win/.test(nav.platform.toLowerCase()) ?
                "Redo - Ctrl+Y" :
                "Redo - Ctrl+Shift+Z"; // mac and other non-Windows platforms

            buttons.redo = makeButton("wmd-redo-button", redoTitle, "glyph-icon icon-rotate-right", null, group4);
            buttons.redo.execute = function (manager) { if (manager) manager.redo(); };

            if (helpOptions) {
                group5 = makeGroup(5);
                group5.className = group5.className + " pull-right";
                var helpButton = document.createElement("button");
                var helpButtonImage = document.createElement("i");
                helpButtonImage.className = "glyph-icon icon-question";
                helpButton.appendChild(helpButtonImage);
                helpButton.className = "btn";
                helpButton.id = "wmd-help-button" + postfix;
                helpButton.isHelp = true;
                helpButton.title = helpOptions.title || defaultHelpHoverTitle;
                $(helpButton).tooltip({placement: 'bottom', container: 'body'})
                helpButton.onclick = helpOptions.handler;

                setupButton(helpButton, true);
                group5.appendChild(helpButton);
                buttons.help = helpButton;
            }

            setUndoRedoButtonStates();
        }

        function setUndoRedoButtonStates() {
            if (undoManager) {
                setupButton(buttons.undo, undoManager.canUndo());
                setupButton(buttons.redo, undoManager.canRedo());
            }
        };

        this.setUndoRedoButtonStates = setUndoRedoButtonStates;

    }

    function CommandManager(pluginHooks) {
        this.hooks = pluginHooks;
    }

    var commandProto = CommandManager.prototype;

    // The markdown symbols - 4 spaces = code, > = blockquote, etc.
    commandProto.prefixes = "(?:\\s{4,}|\\s*>|\\s*-\\s+|\\s*\\d+\\.|=|\\+|-|_|\\*|#|\\s*\\[[^\n]]+\\]:)";

    // Remove markdown symbols from the chunk selection.
    commandProto.unwrap = function (chunk) {
        var txt = new re("([^\\n])\\n(?!(\\n|" + this.prefixes + "))", "g");
        chunk.selection = chunk.selection.replace(txt, "$1 $2");
    };

    commandProto.wrap = function (chunk, len) {
        this.unwrap(chunk);
        var regex = new re("(.{1," + len + "})( +|$\\n?)", "gm"),
            that = this;

        chunk.selection = chunk.selection.replace(regex, function (line, marked) {
            if (new re("^" + that.prefixes, "").test(line)) {
                return line;
            }
            return marked + "\n";
        });

        chunk.selection = chunk.selection.replace(/\s+$/, "");
    };

    commandProto.doBold = function (chunk, postProcessing) {
        return this.doBorI(chunk, postProcessing, 2, "strong text");
    };

    commandProto.doItalic = function (chunk, postProcessing) {
        return this.doBorI(chunk, postProcessing, 1, "emphasized text");
    };

    // chunk: The selected region that will be enclosed with */**
    // nStars: 1 for italics, 2 for bold
    // insertText: If you just click the button without highlighting text, this gets inserted
    commandProto.doBorI = function (chunk, postProcessing, nStars, insertText) {

        // Get rid of whitespace and fixup newlines.
        chunk.trimWhitespace();
        chunk.selection = chunk.selection.replace(/\n{2,}/g, "\n");

        // Look for stars before and after.  Is the chunk already marked up?
        // note that these regex matches cannot fail
        var starsBefore = /(\**$)/.exec(chunk.before)[0];
        var starsAfter = /(^\**)/.exec(chunk.after)[0];

        var prevStars = Math.min(starsBefore.length, starsAfter.length);

        // Remove stars if we have to since the button acts as a toggle.
        if ((prevStars >= nStars) && (prevStars != 2 || nStars != 1)) {
            chunk.before = chunk.before.replace(re("[*]{" + nStars + "}$", ""), "");
            chunk.after = chunk.after.replace(re("^[*]{" + nStars + "}", ""), "");
        }
        else if (!chunk.selection && starsAfter) {
            // It's not really clear why this code is necessary.  It just moves
            // some arbitrary stuff around.
            chunk.after = chunk.after.replace(/^([*_]*)/, "");
            chunk.before = chunk.before.replace(/(\s?)$/, "");
            var whitespace = re.$1;
            chunk.before = chunk.before + starsAfter + whitespace;
        }
        else {

            // In most cases, if you don't have any selected text and click the button
            // you'll get a selected, marked up region with the default text inserted.
            if (!chunk.selection && !starsAfter) {
                chunk.selection = insertText;
            }

            // Add the true markup.
            var markup = nStars <= 1 ? "*" : "**"; // shouldn't the test be = ?
            chunk.before = chunk.before + markup;
            chunk.after = markup + chunk.after;
        }

        return;
    };

    commandProto.stripLinkDefs = function (text, defsToAdd) {

        text = text.replace(/^[ ]{0,3}\[(\d+)\]:[ \t]*\n?[ \t]*<?(\S+?)>?[ \t]*\n?[ \t]*(?:(\n*)["(](.+?)[")][ \t]*)?(?:\n+|$)/gm,
            function (totalMatch, id, link, newlines, title) {
                defsToAdd[id] = totalMatch.replace(/\s*$/, "");
                if (newlines) {
                    // Strip the title and return that separately.
                    defsToAdd[id] = totalMatch.replace(/["(](.+?)[")]$/, "");
                    return newlines + title;
                }
                return "";
            });

        return text;
    };

    commandProto.addLinkDef = function (chunk, linkDef) {

        var refNumber = 0; // The current reference number
        var defsToAdd = {}; //
        // Start with a clean slate by removing all previous link definitions.
        chunk.before = this.stripLinkDefs(chunk.before, defsToAdd);
        chunk.selection = this.stripLinkDefs(chunk.selection, defsToAdd);
        chunk.after = this.stripLinkDefs(chunk.after, defsToAdd);

        var defs = "";
        var regex = /(\[)((?:\[[^\]]*\]|[^\[\]])*)(\][ ]?(?:\n[ ]*)?\[)(\d+)(\])/g;

        var addDefNumber = function (def) {
            refNumber++;
            def = def.replace(/^[ ]{0,3}\[(\d+)\]:/, "  [" + refNumber + "]:");
            defs += "\n" + def;
        };

        // note that
        // a) the recursive call to getLink cannot go infinite, because by definition
        //    of regex, inner is always a proper substring of wholeMatch, and
        // b) more than one level of nesting is neither supported by the regex
        //    nor making a lot of sense (the only use case for nesting is a linked image)
        var getLink = function (wholeMatch, before, inner, afterInner, id, end) {
            inner = inner.replace(regex, getLink);
            if (defsToAdd[id]) {
                addDefNumber(defsToAdd[id]);
                return before + inner + afterInner + refNumber + end;
            }
            return wholeMatch;
        };

        chunk.before = chunk.before.replace(regex, getLink);

        if (linkDef) {
            addDefNumber(linkDef);
        }
        else {
            chunk.selection = chunk.selection.replace(regex, getLink);
        }

        var refOut = refNumber;

        chunk.after = chunk.after.replace(regex, getLink);

        if (chunk.after) {
            chunk.after = chunk.after.replace(/\n*$/, "");
        }
        if (!chunk.after) {
            chunk.selection = chunk.selection.replace(/\n*$/, "");
        }

        chunk.after += "\n\n" + defs;

        return refOut;
    };

    // takes the line as entered into the add link/as image dialog and makes
    // sure the URL and the optinal title are "nice".
    function properlyEncoded(linkdef) {
        return linkdef.replace(/^\s*(.*?)(?:\s+"(.+)")?\s*$/, function (wholematch, link, title) {
            link = link.replace(/\?.*$/, function (querypart) {
                return querypart.replace(/\+/g, " "); // in the query string, a plus and a space are identical
            });
            link = decodeURIComponent(link); // unencode first, to prevent double encoding
            link = encodeURI(link).replace(/'/g, '%27').replace(/\(/g, '%28').replace(/\)/g, '%29');
            link = link.replace(/\?.*$/, function (querypart) {
                return querypart.replace(/\+/g, "%2b"); // since we replaced plus with spaces in the query part, all pluses that now appear where originally encoded
            });
            if (title) {
                title = title.trim ? title.trim() : title.replace(/^\s*/, "").replace(/\s*$/, "");
                title = $.trim(title).replace(/"/g, "quot;").replace(/\(/g, "&#40;").replace(/\)/g, "&#41;").replace(/</g, "&lt;").replace(/>/g, "&gt;");
            }
            return title ? link + ' "' + title + '"' : link;
        });
    }

    commandProto.doLinkOrImage = function (chunk, postProcessing, isImage) {

        chunk.trimWhitespace();
        chunk.findTags(/\s*!?\[/, /\][ ]?(?:\n[ ]*)?(\[.*?\])?/);
        var background;

        if (chunk.endTag.length > 1 && chunk.startTag.length > 0) {

            chunk.startTag = chunk.startTag.replace(/!?\[/, "");
            chunk.endTag = "";
            this.addLinkDef(chunk, null);

        }
        else {

            // We're moving start and end tag back into the selection, since (as we're in the else block) we're not
            // *removing* a link, but *adding* one, so whatever findTags() found is now back to being part of the
            // link text. linkEnteredCallback takes care of escaping any brackets.
            chunk.selection = chunk.startTag + chunk.selection + chunk.endTag;
            chunk.startTag = chunk.endTag = "";

            if (/\n\n/.test(chunk.selection)) {
                this.addLinkDef(chunk, null);
                return;
            }
            var that = this;
            // The function to be executed when you enter a link and press OK or Cancel.
            // Marks up the link and adds the ref.
            var linkEnteredCallback = function (link) {

                if (link !== null) {
                    // (                          $1
                    //     [^\\]                  anything that's not a backslash
                    //     (?:\\\\)*              an even number (this includes zero) of backslashes
                    // )
                    // (?=                        followed by
                    //     [[\]]                  an opening or closing bracket
                    // )
                    //
                    // In other words, a non-escaped bracket. These have to be escaped now to make sure they
                    // don't count as the end of the link or similar.
                    // Note that the actual bracket has to be a lookahead, because (in case of to subsequent brackets),
                    // the bracket in one match may be the "not a backslash" character in the next match, so it
                    // should not be consumed by the first match.
                    // The "prepend a space and finally remove it" steps makes sure there is a "not a backslash" at the
                    // start of the string, so this also works if the selection begins with a bracket. We cannot solve
                    // this by anchoring with ^, because in the case that the selection starts with two brackets, this
                    // would mean a zero-width match at the start. Since zero-width matches advance the string position,
                    // the first bracket could then not act as the "not a backslash" for the second.
                    chunk.selection = (" " + chunk.selection).replace(/([^\\](?:\\\\)*)(?=[[\]])/g, "$1\\").substr(1);

                    var linkDef = " [999]: " + properlyEncoded(link);

                    var num = that.addLinkDef(chunk, linkDef);
                    chunk.startTag = isImage ? "![" : "[";
                    chunk.endTag = "][" + num + "]";

                    if (!chunk.selection) {
                        if (isImage) {
                            chunk.selection = "enter image description here";
                        }
                        else {
                            chunk.selection = "enter link description here";
                        }
                    }
                }
                postProcessing();
            };


            if (isImage) {
                if (!this.hooks.insertImageDialog(linkEnteredCallback))
                    ui.prompt('Insert Image', imageDialogText, imageDefaultText, linkEnteredCallback);
            }
            else {
                ui.prompt('Insert Link', linkDialogText, linkDefaultText, linkEnteredCallback);
            }
            return true;
        }
    };

    // When making a list, hitting shift-enter will put your cursor on the next line
    // at the current indent level.
    commandProto.doAutoindent = function (chunk, postProcessing) {

        var commandMgr = this,
            fakeSelection = false;

        chunk.before = chunk.before.replace(/(\n|^)[ ]{0,3}([*+-]|\d+[.])[ \t]*\n$/, "\n\n");
        chunk.before = chunk.before.replace(/(\n|^)[ ]{0,3}>[ \t]*\n$/, "\n\n");
        chunk.before = chunk.before.replace(/(\n|^)[ \t]+\n$/, "\n\n");

        // There's no selection, end the cursor wasn't at the end of the line:
        // The user wants to split the current list item / code line / blockquote line
        // (for the latter it doesn't really matter) in two. Temporarily select the
        // (rest of the) line to achieve this.
        if (!chunk.selection && !/^[ \t]*(?:\n|$)/.test(chunk.after)) {
            chunk.after = chunk.after.replace(/^[^\n]*/, function (wholeMatch) {
                chunk.selection = wholeMatch;
                return "";
            });
            fakeSelection = true;
        }

        if (/(\n|^)[ ]{0,3}([*+-]|\d+[.])[ \t]+.*\n$/.test(chunk.before)) {
            if (commandMgr.doList) {
                commandMgr.doList(chunk);
            }
        }
        if (/(\n|^)[ ]{0,3}>[ \t]+.*\n$/.test(chunk.before)) {
            if (commandMgr.doBlockquote) {
                commandMgr.doBlockquote(chunk);
            }
        }
        if (/(\n|^)(\t|[ ]{4,}).*\n$/.test(chunk.before)) {
            if (commandMgr.doCode) {
                commandMgr.doCode(chunk);
            }
        }

        if (fakeSelection) {
            chunk.after = chunk.selection + chunk.after;
            chunk.selection = "";
        }
    };

    commandProto.doBlockquote = function (chunk, postProcessing) {

        chunk.selection = chunk.selection.replace(/^(\n*)([^\r]+?)(\n*)$/,
            function (totalMatch, newlinesBefore, text, newlinesAfter) {
                chunk.before += newlinesBefore;
                chunk.after = newlinesAfter + chunk.after;
                return text;
            });

        chunk.before = chunk.before.replace(/(>[ \t]*)$/,
            function (totalMatch, blankLine) {
                chunk.selection = blankLine + chunk.selection;
                return "";
            });

        chunk.selection = chunk.selection.replace(/^(\s|>)+$/, "");
        chunk.selection = chunk.selection || "Blockquote";

        // The original code uses a regular expression to find out how much of the
        // text *directly before* the selection already was a blockquote:

        /*
         if (chunk.before) {
         chunk.before = chunk.before.replace(/\n?$/, "\n");
         }
         chunk.before = chunk.before.replace(/(((\n|^)(\n[ \t]*)*>(.+\n)*.*)+(\n[ \t]*)*$)/,
         function (totalMatch) {
         chunk.startTag = totalMatch;
         return "";
         });
         */

        // This comes down to:
        // Go backwards as many lines a possible, such that each line
        //  a) starts with ">", or
        //  b) is almost empty, except for whitespace, or
        //  c) is preceeded by an unbroken chain of non-empty lines
        //     leading up to a line that starts with ">" and at least one more character
        // and in addition
        //  d) at least one line fulfills a)
        //
        // Since this is essentially a backwards-moving regex, it's susceptible to
        // catstrophic backtracking and can cause the browser to hang;
        // see e.g. http://meta.stackoverflow.com/questions/9807.
        //
        // Hence we replaced this by a simple state machine that just goes through the
        // lines and checks for a), b), and c).

        var match = "",
            leftOver = "",
            line;
        if (chunk.before) {
            var lines = chunk.before.replace(/\n$/, "").split("\n");
            var inChain = false;
            for (var i = 0; i < lines.length; i++) {
                var good = false;
                line = lines[i];
                inChain = inChain && line.length > 0; // c) any non-empty line continues the chain
                if (/^>/.test(line)) {                // a)
                    good = true;
                    if (!inChain && line.length > 1)  // c) any line that starts with ">" and has at least one more character starts the chain
                        inChain = true;
                } else if (/^[ \t]*$/.test(line)) {   // b)
                    good = true;
                } else {
                    good = inChain;                   // c) the line is not empty and does not start with ">", so it matches if and only if we're in the chain
                }
                if (good) {
                    match += line + "\n";
                } else {
                    leftOver += match + line;
                    match = "\n";
                }
            }
            if (!/(^|\n)>/.test(match)) {             // d)
                leftOver += match;
                match = "";
            }
        }

        chunk.startTag = match;
        chunk.before = leftOver;

        // end of change

        if (chunk.after) {
            chunk.after = chunk.after.replace(/^\n?/, "\n");
        }

        chunk.after = chunk.after.replace(/^(((\n|^)(\n[ \t]*)*>(.+\n)*.*)+(\n[ \t]*)*)/,
            function (totalMatch) {
                chunk.endTag = totalMatch;
                return "";
            }
        );

        var replaceBlanksInTags = function (useBracket) {

            var replacement = useBracket ? "> " : "";

            if (chunk.startTag) {
                chunk.startTag = chunk.startTag.replace(/\n((>|\s)*)\n$/,
                    function (totalMatch, markdown) {
                        return "\n" + markdown.replace(/^[ ]{0,3}>?[ \t]*$/gm, replacement) + "\n";
                    });
            }
            if (chunk.endTag) {
                chunk.endTag = chunk.endTag.replace(/^\n((>|\s)*)\n/,
                    function (totalMatch, markdown) {
                        return "\n" + markdown.replace(/^[ ]{0,3}>?[ \t]*$/gm, replacement) + "\n";
                    });
            }
        };

        if (/^(?![ ]{0,3}>)/m.test(chunk.selection)) {
            this.wrap(chunk, SETTINGS.lineLength - 2);
            chunk.selection = chunk.selection.replace(/^/gm, "> ");
            replaceBlanksInTags(true);
            chunk.skipLines();
        } else {
            chunk.selection = chunk.selection.replace(/^[ ]{0,3}> ?/gm, "");
            this.unwrap(chunk);
            replaceBlanksInTags(false);

            if (!/^(\n|^)[ ]{0,3}>/.test(chunk.selection) && chunk.startTag) {
                chunk.startTag = chunk.startTag.replace(/\n{0,2}$/, "\n\n");
            }

            if (!/(\n|^)[ ]{0,3}>.*$/.test(chunk.selection) && chunk.endTag) {
                chunk.endTag = chunk.endTag.replace(/^\n{0,2}/, "\n\n");
            }
        }

        chunk.selection = this.hooks.postBlockquoteCreation(chunk.selection);

        if (!/\n/.test(chunk.selection)) {
            chunk.selection = chunk.selection.replace(/^(> *)/,
                function (wholeMatch, blanks) {
                    chunk.startTag += blanks;
                    return "";
                });
        }
    };

    commandProto.doCode = function (chunk, postProcessing) {

        var hasTextBefore = /\S[ ]*$/.test(chunk.before);
        var hasTextAfter = /^[ ]*\S/.test(chunk.after);

        // Use 'four space' markdown if the selection is on its own
        // line or is multiline.
        if ((!hasTextAfter && !hasTextBefore) || /\n/.test(chunk.selection)) {

            chunk.before = chunk.before.replace(/[ ]{4}$/,
                function (totalMatch) {
                    chunk.selection = totalMatch + chunk.selection;
                    return "";
                });

            var nLinesBack = 1;
            var nLinesForward = 1;

            if (/(\n|^)(\t|[ ]{4,}).*\n$/.test(chunk.before)) {
                nLinesBack = 0;
            }
            if (/^\n(\t|[ ]{4,})/.test(chunk.after)) {
                nLinesForward = 0;
            }

            chunk.skipLines(nLinesBack, nLinesForward);

            if (!chunk.selection) {
                chunk.startTag = "    ";
                chunk.selection = "enter code here";
            }
            else {
                if (/^[ ]{0,3}\S/m.test(chunk.selection)) {
                    if (/\n/.test(chunk.selection))
                        chunk.selection = chunk.selection.replace(/^/gm, "    ");
                    else // if it's not multiline, do not select the four added spaces; this is more consistent with the doList behavior
                        chunk.before += "    ";
                }
                else {
                    chunk.selection = chunk.selection.replace(/^[ ]{4}/gm, "");
                }
            }
        }
        else {
            // Use backticks (`) to delimit the code block.

            chunk.trimWhitespace();
            chunk.findTags(/`/, /`/);

            if (!chunk.startTag && !chunk.endTag) {
                chunk.startTag = chunk.endTag = "`";
                if (!chunk.selection) {
                    chunk.selection = "enter code here";
                }
            }
            else if (chunk.endTag && !chunk.startTag) {
                chunk.before += chunk.endTag;
                chunk.endTag = "";
            }
            else {
                chunk.startTag = chunk.endTag = "";
            }
        }
    };

    commandProto.doList = function (chunk, postProcessing, isNumberedList) {

        // These are identical except at the very beginning and end.
        // Should probably use the regex extension function to make this clearer.
        var previousItemsRegex = /(\n|^)(([ ]{0,3}([*+-]|\d+[.])[ \t]+.*)(\n.+|\n{2,}([*+-].*|\d+[.])[ \t]+.*|\n{2,}[ \t]+\S.*)*)\n*$/;
        var nextItemsRegex = /^\n*(([ ]{0,3}([*+-]|\d+[.])[ \t]+.*)(\n.+|\n{2,}([*+-].*|\d+[.])[ \t]+.*|\n{2,}[ \t]+\S.*)*)\n*/;

        // The default bullet is a dash but others are possible.
        // This has nothing to do with the particular HTML bullet,
        // it's just a markdown bullet.
        var bullet = "-";

        // The number in a numbered list.
        var num = 1;

        // Get the item prefix - e.g. " 1. " for a numbered list, " - " for a bulleted list.
        var getItemPrefix = function () {
            var prefix;
            if (isNumberedList) {
                prefix = " " + num + ". ";
                num++;
            }
            else {
                prefix = " " + bullet + " ";
            }
            return prefix;
        };

        // Fixes the prefixes of the other list items.
        var getPrefixedItem = function (itemText) {

            // The numbering flag is unset when called by autoindent.
            if (isNumberedList === undefined) {
                isNumberedList = /^\s*\d/.test(itemText);
            }

            // Renumber/bullet the list element.
            itemText = itemText.replace(/^[ ]{0,3}([*+-]|\d+[.])\s/gm,
                function (_) {
                    return getItemPrefix();
                });

            return itemText;
        };

        chunk.findTags(/(\n|^)*[ ]{0,3}([*+-]|\d+[.])\s+/, null);

        if (chunk.before && !/\n$/.test(chunk.before) && !/^\n/.test(chunk.startTag)) {
            chunk.before += chunk.startTag;
            chunk.startTag = "";
        }

        if (chunk.startTag) {

            var hasDigits = /\d+[.]/.test(chunk.startTag);
            chunk.startTag = "";
            chunk.selection = chunk.selection.replace(/\n[ ]{4}/g, "\n");
            this.unwrap(chunk);
            chunk.skipLines();

            if (hasDigits) {
                // Have to renumber the bullet points if this is a numbered list.
                chunk.after = chunk.after.replace(nextItemsRegex, getPrefixedItem);
            }
            if (isNumberedList == hasDigits) {
                return;
            }
        }

        var nLinesUp = 1;

        chunk.before = chunk.before.replace(previousItemsRegex,
            function (itemText) {
                if (/^\s*([*+-])/.test(itemText)) {
                    bullet = re.$1;
                }
                nLinesUp = /[^\n]\n\n[^\n]/.test(itemText) ? 1 : 0;
                return getPrefixedItem(itemText);
            });

        if (!chunk.selection) {
            chunk.selection = "List item";
        }

        var prefix = getItemPrefix();

        var nLinesDown = 1;

        chunk.after = chunk.after.replace(nextItemsRegex,
            function (itemText) {
                nLinesDown = /[^\n]\n\n[^\n]/.test(itemText) ? 1 : 0;
                return getPrefixedItem(itemText);
            });

        chunk.trimWhitespace(true);
        chunk.skipLines(nLinesUp, nLinesDown, true);
        chunk.startTag = prefix;
        var spaces = prefix.replace(/./g, " ");
        this.wrap(chunk, SETTINGS.lineLength - spaces.length);
        chunk.selection = chunk.selection.replace(/\n/g, "\n" + spaces);

    };

    commandProto.doHeading = function (chunk, postProcessing) {

        // Remove leading/trailing whitespace and reduce internal spaces to single spaces.
        chunk.selection = chunk.selection.replace(/\s+/g, " ");
        chunk.selection = chunk.selection.replace(/(^\s+|\s+$)/g, "");

        // If we clicked the button with no selected text, we just
        // make a level 2 hash header around some default text.
        if (!chunk.selection) {
            chunk.startTag = "## ";
            chunk.selection = "Heading";
            chunk.endTag = " ##";
            return;
        }

        var headerLevel = 0;     // The existing header level of the selected text.

        // Remove any existing hash heading markdown and save the header level.
        chunk.findTags(/#+[ ]*/, /[ ]*#+/);
        if (/#+/.test(chunk.startTag)) {
            headerLevel = re.lastMatch.length;
        }
        chunk.startTag = chunk.endTag = "";

        // Try to get the current header level by looking for - and = in the line
        // below the selection.
        chunk.findTags(null, /\s?(-+|=+)/);
        if (/=+/.test(chunk.endTag)) {
            headerLevel = 1;
        }
        if (/-+/.test(chunk.endTag)) {
            headerLevel = 2;
        }

        // Skip to the next line so we can create the header markdown.
        chunk.startTag = chunk.endTag = "";
        chunk.skipLines(1, 1);

        // We make a level 2 header if there is no current header.
        // If there is a header level, we substract one from the header level.
        // If it's already a level 1 header, it's removed.
        var headerLevelToCreate = headerLevel == 0 ? 2 : headerLevel - 1;

        if (headerLevelToCreate > 0) {

            // The button only creates level 1 and 2 underline headers.
            // Why not have it iterate over hash header levels?  Wouldn't that be easier and cleaner?
            var headerChar = headerLevelToCreate >= 2 ? "-" : "=";
            var len = chunk.selection.length;
            if (len > SETTINGS.lineLength) {
                len = SETTINGS.lineLength;
            }
            chunk.endTag = "\n";
            while (len--) {
                chunk.endTag += headerChar;
            }
        }
    };

    commandProto.doHorizontalRule = function (chunk, postProcessing) {
        chunk.startTag = "----------\n";
        chunk.selection = "";
        chunk.skipLines(2, 1, true);
    }


})();

(function () {
    var output, Converter;
    if (typeof exports === "object" && typeof require === "function") { // we're in a CommonJS (e.g. Node.js) module
        output = exports;
        Converter = require("./Markdown.Converter").Converter;
    } else {
        output = window.Markdown;
        Converter = output.Converter;
    }

    output.getSanitizingConverter = function () {
        var converter = new Converter();
        converter.hooks.chain("postConversion", sanitizeHtml);
        converter.hooks.chain("postConversion", balanceTags);
        return converter;
    }

    function sanitizeHtml(html) {
        return html.replace(/<[^>]*>?/gi, sanitizeTag);
    }

    // (tags that can be opened/closed) | (tags that stand alone)
    var basic_tag_whitelist = /^(<\/?(b|blockquote|code|del|dd|dl|dt|em|h1|h2|h3|i|kbd|li|ol|p|s|sup|sub|strong|strike|ul)>|<(br|hr)\s?\/?>)$/i;
    // <a href="url..." optional title>|</a>
    var a_white = /^(<a\shref="(https?:(\/\/|\/)|ftp:(\/\/|\/)|mailto:|magnet:)[-A-Za-z0-9+&@#\/%?=~_|!:,.;\(\)]+"(\stitle="[^"<>]+")?\s?>|<\/a>)$/i;

    // <img src="url..." optional width  optional height  optional alt  optional title
    var img_white = /^(<img\ssrc="(https?:\/\/|\/)[-A-Za-z0-9+&@#\/%?=~_|!:,.;\(\)]+"(\swidth="\d{1,3}")?(\sheight="\d{1,3}")?(\salt="[^"<>]*")?(\stitle="[^"<>]*")?\s?\/?>)$/i;

    // <pre optional class="prettyprint linenums">|</pre> for twitter bootstrap
    var pre_white = /^(<pre(\sclass="prettyprint linenums")?>|<\/pre>)$/i;

    function sanitizeTag(tag) {
        if (tag.match(basic_tag_whitelist) || tag.match(a_white) || tag.match(img_white) || tag.match(pre_white))
            return tag;
        else
            return "";
    }

    /// <summary>
    /// attempt to balance HTML tags in the html string
    /// by removing any unmatched opening or closing tags
    /// IMPORTANT: we *assume* HTML has *already* been
    /// sanitized and is safe/sane before balancing!
    ///
    /// adapted from CODESNIPPET: A8591DBA-D1D3-11DE-947C-BA5556D89593
    /// </summary>
    function balanceTags(html) {

        if (html == "")
            return "";

        var re = /<\/?\w+[^>]*(\s|$|>)/g;
        // convert everything to lower case; this makes
        // our case insensitive comparisons easier
        var tags = html.toLowerCase().match(re);

        // no HTML tags present? nothing to do; exit now
        var tagcount = (tags || []).length;
        if (tagcount == 0)
            return html;

        var tagname, tag;
        var ignoredtags = "<p><img><br><li><hr>";
        var match;
        var tagpaired = [];
        var tagremove = [];
        var needsRemoval = false;

        // loop through matched tags in forward order
        for (var ctag = 0; ctag < tagcount; ctag++) {
            tagname = tags[ctag].replace(/<\/?(\w+).*/, "$1");
            // skip any already paired tags
            // and skip tags in our ignore list; assume they're self-closed
            if (tagpaired[ctag] || ignoredtags.search("<" + tagname + ">") > -1)
                continue;

            tag = tags[ctag];
            match = -1;

            if (!/^<\//.test(tag)) {
                // this is an opening tag
                // search forwards (next tags), look for closing tags
                for (var ntag = ctag + 1; ntag < tagcount; ntag++) {
                    if (!tagpaired[ntag] && tags[ntag] == "</" + tagname + ">") {
                        match = ntag;
                        break;
                    }
                }
            }

            if (match == -1)
                needsRemoval = tagremove[ctag] = true; // mark for removal
            else
                tagpaired[match] = true; // mark paired
        }

        if (!needsRemoval)
            return html;

        // delete all orphaned tags from the string

        var ctag = 0;
        html = html.replace(re, function (match) {
            var res = tagremove[ctag] ? "" : match;
            ctag++;
            return res;
        });
        return html;
    }
})();

/*
 * Pagedown Bootstrap
 * Author: Kevin O'Connor
 * Version: 1.0
 *
 * Copyright (c) 2013 Kevin O'Connor
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of this software and
 * associated documentation files (the "Software"), to deal in the Software without restriction,
 * including without limitation the rights to use, copy, modify, merge, publish, distribute,
 * sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all copies or
 * substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING
 * BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 *
 */

(function( $ ){

    $.fn.pagedownBootstrap = function( options ) {

        // Default settings
        var settings = $.extend( {
            'sanitize'				: true,
            'help'						: null,
            'hooks'						: Array()
        }, options);

        return this.each(function() {

            //Setup converter
            var converter = null;
            if(settings.sanitize)
            {
                converter = Markdown.getSanitizingConverter();
            } else {
                converter = new Markdown.Converter()
            }

            //Register hooks
            for(var i in settings.hooks)
            {
                var hook = settings.hooks[i];
                if(typeof hook !== 'object' || typeof hook.event === 'undefined'
                    || typeof hook.callback !== 'function')
                {
                    //A bad hook object was given
                    continue;
                }

                converter.hooks.chain(hook.event, hook.callback);

            }

            //Try to find a valid id for this element
            var id = "wmd-input";
            var idAppend = 0;
            while($("#"+id+"-"+idAppend.toString()).length > 0)
            {
                idAppend++;
            }

            //Assign the choosen id to the element
            $(this).attr('id', id+"-"+idAppend.toString());

            //Wrap the element with the needed html
            $(this).wrap('<div class="wmd-panel" />');
            $(this).before('<div id="wmd-button-bar-'+idAppend+'" class="wmd-button-bar" />');
            $(this).after('<div id="wmd-preview-'+idAppend+'" class="wmd-preview" />');
            $(this).addClass('wmd-input');

            //Setup help function
            help = null;
            if($.isFunction(settings.help))
            {
                help = { handler: settings.help };
            }

            //Setup editor
            var editor = new Markdown.Editor(converter, "-"+idAppend.toString(), help);
            editor.run();

        });

    };
})( jQuery );
