'use strict';

var Markdown = {
    render: function(md) {
        if (!md) return '';
        var html = md;

        // Code blocks
        html = html.replace(/```(\w*)\n([\s\S]*?)```/g, function(_, lang, code) {
            return '<pre><code class="lang-' + lang + '">' + Markdown.esc(code.trim()) + '</code></pre>';
        });

        // Inline code
        html = html.replace(/`([^`]+)`/g, '<code>$1</code>');

        // Bold
        html = html.replace(/\*\*(.+?)\*\*/g, '<strong>$1</strong>');

        // Italic
        html = html.replace(/\*(.+?)\*/g, '<em>$1</em>');

        // Headings
        html = html.replace(/^### (.+)$/gm, '<h3>$1</h3>');
        html = html.replace(/^## (.+)$/gm, '<h2>$1</h2>');
        html = html.replace(/^# (.+)$/gm, '<h1>$1</h1>');

        // HR
        html = html.replace(/^---$/gm, '<hr>');

        // Tables
        html = html.replace(/^\|(.+)\|\s*\n\|[-| :]+\|\s*\n((?:\|.+\|\s*\n?)*)/gm, function(_, header, rows) {
            var ths = header.split('|').map(function(h) { return '<th>' + h.trim() + '</th>'; }).join('');
            var trs = rows.trim().split('\n').map(function(row) {
                var tds = row.replace(/^\||\|$/g, '').split('|').map(function(c) { return '<td>' + c.trim() + '</td>'; }).join('');
                return '<tr>' + tds + '</tr>';
            }).join('');
            return '<table><thead><tr>' + ths + '</tr></thead><tbody>' + trs + '</tbody></table>';
        });

        // Lists
        html = html.replace(/^- (.+)$/gm, '<li>$1</li>');
        html = html.replace(/(<li>[\s\S]*?<\/li>)/g, function(match) {
            if (match.indexOf('<ul>') === -1) return '<ul>' + match + '</ul>';
            return match;
        });

        // Paragraphs
        html = html.replace(/^(?!<[huptlo]|<\/|<hr|<pre|<li|<ul)(.+)$/gm, '<p>$1</p>');

        return html;
    },

    esc: function(str) {
        return str.replace(/&/g, '&amp;').replace(/</g, '&lt;').replace(/>/g, '&gt;');
    }
};