src/api/pdf.js

import puppeteer from 'puppeteer';
import { marked } from 'marked';

export async function generatePdf(markdownContent, title = "SchoolMind Lösung") {
  const htmlContent = marked.parse(markdownContent);
  
  const fullHtml = `
    <!DOCTYPE html>
    <html lang="de">
    <head>
      <meta charset="UTF-8">
      <title>${title}</title>
      <style>
        body {
          font-family: 'Helvetica Neue', Helvetica, Arial, sans-serif;
          font-size: 11pt;
          line-height: 1.6;
          color: #333;
          margin: 40px;
        }
        h1, h2, h3 {
          color: #1a1a1a;
          margin-top: 1.5em;
          margin-bottom: 0.5em;
        }
        h1 { font-size: 24px; border-bottom: 2px solid #eaeaea; padding-bottom: 10px; }
        h2 { font-size: 20px; }
        h3 { font-size: 16px; }
        p { margin-bottom: 15px; }
        code {
          background-color: #f4f4f4;
          padding: 2px 4px;
          border-radius: 4px;
          font-family: 'Courier New', Courier, monospace;
        }
        pre {
          background-color: #f4f4f4;
          padding: 15px;
          border-radius: 8px;
          overflow-x: auto;
        }
        pre code {
          background-color: transparent;
          padding: 0;
        }
        blockquote {
          border-left: 4px solid #8a53e6;
          margin: 0;
          padding-left: 15px;
          color: #555;
          font-style: italic;
        }
        ul, ol { margin-bottom: 15px; }
        li { margin-bottom: 5px; }
        
        /* Prevent awkward page breaks */
        p, li, h1, h2, h3, pre, blockquote {
          page-break-inside: avoid;
          break-inside: avoid;
        }
        h1, h2, h3 {
          page-break-after: avoid;
          break-after: avoid;
        }
      </style>
    </head>
    <body>
      ${htmlContent}
    </body>
    </html>
  `;

  let browser;
  try {
    browser = await puppeteer.launch({
      headless: "new",
      args: ['--no-sandbox', '--disable-setuid-sandbox']
    });
    const page = await browser.newPage();
    await page.setContent(fullHtml, { waitUntil: 'networkidle0' });
    
    const pdfBuffer = await page.pdf({
      format: 'A4',
      margin: {
        top: '40px',
        right: '40px',
        bottom: '40px',
        left: '40px'
      },
      printBackground: true,
      displayHeaderFooter: false
    });
    
    return pdfBuffer;
  } catch (e) {
    console.error("Fehler beim PDF Generieren:", e);
    throw e;
  } finally {
    if (browser) {
      await browser.close();
    }
  }
}