const express = require('express');
const path = require('path');
const { GoogleAuth } = require('google-auth-library');

const app = express();
app.use(express.json({ limit: '1mb' }));

const BACKEND_URL = process.env.BACKEND_URL;
if (!BACKEND_URL) {
  console.error('FATAL: BACKEND_URL env var is required');
  process.exit(1);
}

const auth = new GoogleAuth();

app.get('/health', (_req, res) => {
  res.status(200).json({ status: 'ok' });
});

app.post('/api/chat', async (req, res) => {
    console.log('🔥🔥🔥 /api/chat ROUTE HIT 🔥🔥🔥');
  try {
    // Create an ID-token authenticated client for the backend (audience = BACKEND_URL)
    const idTokenClient = await auth.getIdTokenClient(BACKEND_URL);

    // Forward request to backend
    const backendResp = await idTokenClient.request({
      url: `${BACKEND_URL}/chat`,
      method: 'POST',
      data: req.body,
    });

    res.status(backendResp.status).json(backendResp.data);
  } catch (err) {
    console.error('Proxy error FULL:', {
    message: err.message,
    responseStatus: err.response?.status,
    responseData: err.response?.data,
    stack: err.stack,
  });
    const status = err.response?.status || 500;
    const message = err.response?.data || { error: err.message };
    res.status(err.response?.status || 500).json({
    error: err.response?.data || err.message || 'Unknown proxy error',
  });
  }
});

// Serve static assets
app.use(express.static(path.join(__dirname, 'dist')));

// SPA fallback
app.get('*', (_req, res) => {
  res.sendFile(path.join(__dirname, 'dist', 'index.html'));
});

const port = parseInt(process.env.PORT || '8080', 10);
app.listen(port, '0.0.0.0', () => {
  console.log(`Frontend proxy listening on port ${port}`);
});