import express from 'express';
import path from 'path';
import { getOptimizedModelPath } from '../services/modelsProxyService.js';

const router = express.Router();

/**
 * GET /api/models/3d/falukant/characters/:filename
 * Liefert die Draco-optimierte GLB-Datei (aus Cache oder nach Optimierung).
 */
router.get('/3d/falukant/characters/:filename', async (req, res) => {
  const { filename } = req.params;

  try {
    const cachePath = await getOptimizedModelPath(filename);
    res.setHeader('Content-Type', 'model/gltf-binary');
    // GLB files can be replaced under the same filename during an asset deploy.
    // Revalidate cached copies so clients receive a changed mesh without needing
    // to clear their browser cache.
    res.setHeader('Cache-Control', 'public, max-age=0, must-revalidate');
    res.sendFile(cachePath);
  } catch (e) {
    if (e.message?.includes('Invalid model filename') || e.message?.includes('not found')) {
      return res.status(404).send(e.message);
    }
    console.error('[models-proxy]', e.message);
    res.status(500).send('Model optimization failed');
  }
});

export default router;