markdown-parser.php

<?php
/**
 * Simple Markdown to HTML Converter
 * Handles basic markdown syntax for documentation pages
 */

function parseMarkdown($markdown) {
    // Escape HTML first
    $markdown = htmlspecialchars($markdown, ENT_NOQUOTES);
    
    // Headers
    $markdown = preg_replace('/^##### (.*?)$/m', '<h5>$1</h5>', $markdown);
    $markdown = preg_replace('/^#### (.*?)$/m', '<h4>$1</h4>', $markdown);
    $markdown = preg_replace('/^### (.*?)$/m', '<h3>$1</h3>', $markdown);
    $markdown = preg_replace('/^## (.*?)$/m', '<h2>$1</h2>', $markdown);
    $markdown = preg_replace('/^# (.*?)$/m', '<h1>$1</h1>', $markdown);
    
    // Code blocks (```language ... ```)
    $markdown = preg_replace_callback('/```(.*?)\n(.*?)```/s', function($matches) {
        $language = $matches[1];
        $code = $matches[2];
        return '<pre><code class="language-' . htmlspecialchars($language) . '">' . $code . '</code></pre>';
    }, $markdown);
    
    // Inline code (`code`)
    $markdown = preg_replace('/`([^`]+)`/', '<code>$1</code>', $markdown);
    
    // Bold (**text** or __text__)
    $markdown = preg_replace('/\*\*(.+?)\*\*/', '<strong>$1</strong>', $markdown);
    $markdown = preg_replace('/__(.+?)__/', '<strong>$1</strong>', $markdown);
    
    // Italic (*text* or _text_)
    $markdown = preg_replace('/\*(.+?)\*/', '<em>$1</em>', $markdown);
    $markdown = preg_replace('/_(.+?)_/', '<em>$1</em>', $markdown);
    
    // Links [text](url)
    $markdown = preg_replace('/\[([^\]]+)\]\(([^)]+)\)/', '<a href="$2" target="_blank">$1</a>', $markdown);
    
    // Images ![alt](url)
    $markdown = preg_replace('/!\[([^\]]*)\]\(([^)]+)\)/', '<img src="$2" alt="$1" class="img-fluid" />', $markdown);
    
    // Horizontal rules (--- or ***)
    $markdown = preg_replace('/^---$/m', '<hr>', $markdown);
    $markdown = preg_replace('/^\*\*\*$/m', '<hr>', $markdown);
    
    // Blockquotes (> text)
    $markdown = preg_replace('/^&gt; (.*)$/m', '<blockquote>$1</blockquote>', $markdown);
    
    // Unordered lists (- item or * item)
    $markdown = preg_replace_callback('/(?:^[-*] .+$\n?)+/m', function($matches) {
        $items = preg_replace('/^[-*] (.+)$/m', '<li>$1</li>', $matches[0]);
        return '<ul>' . $items . '</ul>';
    }, $markdown);
    
    // Ordered lists (1. item)
    $markdown = preg_replace_callback('/(?:^\d+\. .+$\n?)+/m', function($matches) {
        $items = preg_replace('/^\d+\. (.+)$/m', '<li>$1</li>', $matches[0]);
        return '<ol>' . $items . '</ol>';
    }, $markdown);
    
    // Tables
    $markdown = preg_replace_callback('/(?:^\|.+\|$\n?)+/m', function($matches) {
        $lines = explode("\n", trim($matches[0]));
        $html = '<table class="table table-bordered">';
        
        foreach ($lines as $i => $line) {
            if (preg_match('/^\|[-: |]+\|$/', $line)) {
                continue; // Skip separator line
            }
            
            $cells = array_map('trim', explode('|', trim($line, '|')));
            $tag = ($i === 0) ? 'th' : 'td';
            
            $html .= '<tr>';
            foreach ($cells as $cell) {
                $html .= "<$tag>$cell</$tag>";
            }
            $html .= '</tr>';
        }
        
        $html .= '</table>';
        return $html;
    }, $markdown);
    
    // Checkboxes
    $markdown = preg_replace('/\[x\]/i', '<i class="bi bi-check-square-fill text-success"></i>', $markdown);
    $markdown = preg_replace('/\[ \]/', '<i class="bi bi-square"></i>', $markdown);
    
    // Paragraphs
    $markdown = preg_replace('/\n\n/', '</p><p>', $markdown);
    $markdown = '<p>' . $markdown . '</p>';
    
    // Clean up empty paragraphs
    $markdown = preg_replace('/<p>\s*<\/p>/', '', $markdown);
    $markdown = preg_replace('/<p>(\s*<(?:h[1-6]|ul|ol|table|pre|hr|blockquote))/i', '$1', $markdown);
    $markdown = preg_replace('/(<\/(?:h[1-6]|ul|ol|table|pre|hr|blockquote)>)\s*<\/p>/i', '$1', $markdown);
    
    // Line breaks
    $markdown = str_replace("\n", '<br>', $markdown);
    
    return $markdown;
}

function loadMarkdownFile($filename, $title) {
    $filepath = __DIR__ . '/../' . $filename;
    
    if (!file_exists($filepath)) {
        http_response_code(404);
        return [
            'title' => '404 - Not Found',
            'content' => '<h1>Document Not Found</h1><p>The requested documentation file could not be found.</p>'
        ];
    }
    
    $markdown = file_get_contents($filepath);
    $html = parseMarkdown($markdown);
    
    return [
        'title' => $title,
        'content' => $html
    ];
}