import { marked } from 'marked';
import DOMPurify from 'dompurify';
import hljs from 'highlight.js/lib/core';
import javascript from 'highlight.js/lib/languages/javascript';
import bash from 'highlight.js/lib/languages/bash';
import typescript from 'highlight.js/lib/languages/typescript';
import json from 'highlight.js/lib/languages/json';

hljs.registerLanguage('javascript', javascript);
hljs.registerLanguage('js', javascript);
hljs.registerLanguage('typescript', typescript);
hljs.registerLanguage('ts', typescript);
hljs.registerLanguage('bash', bash);
hljs.registerLanguage('sh', bash);
hljs.registerLanguage('json', json);

marked.use({
  breaks: true,
  gfm: true,
  renderer: {
    code({ text, lang }) {
      const language = lang && hljs.getLanguage(lang) ? lang : undefined;
      const highlighted = language
        ? hljs.highlight(text, { language }).value
        : hljs.highlightAuto(text).value;
      const cls = language ? ` language-${language}` : '';
      return `<pre><code class="hljs${cls}">${highlighted}</code></pre>`;
    },
  },
});

/**
 * Rendert einen Markdown-String zu sanitized HTML.
 * Einziger Export des Moduls — so bleibt Austausch der Engine lokal.
 */
export function renderMarkdown(md: string): string {
  const raw = marked.parse(md, { async: false }) as string;
  return DOMPurify.sanitize(raw, {
    ADD_ATTR: ['target', 'rel'],
  });
}