md.js

// Markdown parser - JS port of PHP Util::md() for identical rendering
// Copyright (C) 2015-2026 Mark Constable <mc@netserva.org> (MIT License)

function md(s) {
    const b = [], L = '\x02', R = '\x03';
    const esc = t => t.replace(/&/g,'&amp;').replace(/</g,'&lt;').replace(/>/g,'&gt;');

    // Protect code blocks
    s = s.replace(/```(\w*)\r?\n([\s\S]*?)\r?\n```/g, (_, lang, code) => {
        const cls = lang ? ` class="lang-${lang}"` : '';
        b.push(`${L}pre${R}${L}code${cls}${R}${esc(code.trimEnd())}${L}/code${R}${L}/pre${R}`);
        return `\x00${b.length - 1}\x00`;
    });
    s = s.replace(/`([^`\n]+)`/g, (_, code) => {
        b.push(`${L}code${R}${esc(code)}${L}/code${R}`);
        return `\x00${b.length - 1}\x00`;
    });

    // GFM Tables
    s = s.replace(/^(\|.+\|)\r?\n(\|[-:\| ]+\|)\r?\n((?:\|.+\|\r?\n?)+)/gm, (_, hdr, align, body) => {
        const hdrs = hdr.split('|').filter(c => c.trim()).map(c => c.trim());
        const aligns = align.split('|').filter(c => c.trim()).map(c => {
            c = c.trim();
            if (c.startsWith(':') && c.endsWith(':')) return 'center';
            if (c.endsWith(':')) return 'right';
            return 'left';
        });
        const th = hdrs.map((h, i) => `${L}th style="text-align:${aligns[i]}"${R}${h}${L}/th${R}`).join('');
        const rows = body.trim().split('\n').map(r => {
            const cells = r.split('|').filter(c => c.trim()).map(c => c.trim());
            return `${L}tr${R}${cells.map((c, i) => `${L}td style="text-align:${aligns[i] || 'left'}"${R}${c}${L}/td${R}`).join('')}${L}/tr${R}`;
        }).join('');
        return `${L}table${R}${L}thead${R}${L}tr${R}${th}${L}/tr${R}${L}/thead${R}${L}tbody${R}${rows}${L}/tbody${R}${L}/table${R}`;
    });

    // Block elements
    s = s.replace(/^(#{1,6})\s+(.+)$/gm, (_, h, t) => `${L}h${h.length}${R}${t.trim()}${L}/h${h.length}${R}`);
    s = s.replace(/^[-*_]{3,}\s*$/gm, `${L}hr${R}`);
    s = s.replace(/^>\s*(.+)$/gm, `${L}blockquote${R}$1${L}/blockquote${R}`);

    // Lists
    s = s.replace(/^[-*+]\s+(.+)$/gm, `${L}ul${R}${L}li${R}$1${L}/li${R}${L}/ul${R}`);
    s = s.replace(/^\d+\.\s+(.+)$/gm, `${L}ol${R}${L}li${R}$1${L}/li${R}${L}/ol${R}`);
    s = s.replace(new RegExp(`${L}/ul${R}\\s*${L}ul${R}`, 'g'), '');
    s = s.replace(new RegExp(`${L}/ol${R}\\s*${L}ol${R}`, 'g'), '');
    s = s.replace(new RegExp(`${L}/blockquote${R}\\s*${L}blockquote${R}`, 'g'), '\n');

    // Inline elements
    s = s.replace(/!\[([^\]]*)\]\(([^)\s]+)\)/g, `${L}img src="$2" alt="$1"${R}`);
    s = s.replace(/\[([^\]]+)\]\(([^)]+)\)/g, `${L}a href="$2"${R}$1${L}/a${R}`);
    s = s.replace(/(\*\*|__)(.+?)\1/g, `${L}strong${R}$2${L}/strong${R}`);
    s = s.replace(/\*([^*\n]+)\*/g, `${L}em${R}$1${L}/em${R}`);
    s = s.replace(/(?<![^\s])_([^_\n]+)_(?![^\s])/g, `${L}em${R}$1${L}/em${R}`);
    s = s.replace(/~~(.+?)~~/g, `${L}del${R}$1${L}/del${R}`);

    // Join consecutive badge lines (linked images) into single line
    s = s.replace(new RegExp(`(${L}a[^${R}]*${R}${L}img[^${R}]*${R}${L}/a${R})\n(?=${L}a)`, 'g'), '$1 ');

    // Finalize - escape remaining content, restore protected blocks
    s = esc(s);
    s = s.replace(/\x00(\d+)\x00/g, (_, i) => b[parseInt(i)]);
    s = s.replace(/\x02/g, '<').replace(/\x03/g, '>');

    // Paragraphs
    return s.split(/\n{2,}/).map(p => {
        p = p.trim();
        if (!p) return '';
        if (/^<(?:h[1-6]|ul|ol|blockquote|hr|pre|table)/.test(p)) return p;
        return '<p>' + p.replace(/\n/g, '<br>') + '</p>';
    }).join('\n').trim();
}

// Rewrite an authored .md link (relative to the docs root) to its clean page URL.
// e.g. "01-Simple/README.md" -> "<root>01-Simple/", "CONVENTIONS.md" -> "<root>conventions/".
function cleanDocHref(href, root) {
    if (/^(#|[a-z]+:|\/\/)/i.test(href)) return href;          // anchors, http:, mailto: … left alone
    if (/(^|\/)README\.md$/.test(href)) {
        const dir = href.replace(/README\.md$/, '');
        return (root + dir) || './';
    }
    if (/CONVENTIONS\.md$/i.test(href)) return root + 'conventions/';
    if (/\.md$/i.test(href)) return root + href;
    return href;
}

// Render the page's own Markdown into #content (one page = one document, real URLs, no hash).
(function() {
    const init = () => {
        const el = document.getElementById('content');
        if (!el || !el.dataset.md) return;
        const root = el.dataset.root || '';
        fetch(el.dataset.md)
            .then(r => { if (!r.ok) throw new Error(r.status); return r.text(); })
            .then(src => {
                el.innerHTML = md(src);
                el.querySelectorAll('a[href]').forEach(a =>
                    a.setAttribute('href', cleanDocHref(a.getAttribute('href'), root)));
                if (typeof lucide !== 'undefined') lucide.createIcons();
            })
            .catch(() => { el.innerHTML = '<p>Sorry, this document could not be loaded.</p>'; });
    };
    document.readyState === 'loading' ? document.addEventListener('DOMContentLoaded', init) : init();
})();