import { Router } from 'express';
import { resolveAndValidateHost, safeFetch } from './ssrf-guard';

const router = Router();

router.get('/image-proxy', async (req, res) => {
  try {
    const url = String(req.query.url || '');

    if (!/^https?:\/\//i.test(url)) {
      return res.status(400).json({ error: 'Invalid URL' });
    }

    const hostAllowed = await resolveAndValidateHost(url);

    if (!hostAllowed) {
      return res.status(400).json({ error: 'URL resolves to a blocked address' });
    }

    const controller = new AbortController();
    const timeout = setTimeout(() => controller.abort(), 8000);
    const response = await safeFetch(url, { signal: controller.signal });

    clearTimeout(timeout);

    if (!response || !response.ok) {
      return res.status(response?.status ?? 502).end();
    }

    const contentType = response.headers.get('content-type') || '';

    if (!contentType.toLowerCase().startsWith('image/')) {
      return res.status(415).json({ error: 'Unsupported content type' });
    }

    const arrayBuffer = await response.arrayBuffer();
    const MAX_BYTES = 8 * 1024 * 1024;

    if (arrayBuffer.byteLength > MAX_BYTES) {
      return res.status(413).json({ error: 'Image too large' });
    }

    res.setHeader('Content-Type', contentType);
    res.setHeader('Cache-Control', 'public, max-age=3600');
    res.send(Buffer.from(arrayBuffer));
  } catch (err) {
    if ((err as { name?: string })?.name === 'AbortError') {
      return res.status(504).json({ error: 'Timeout fetching image' });
    }

    console.error('Image proxy error:', err);
    res.status(502).json({ error: 'Failed to fetch image' });
  }
});

export default router;