Receber webhooks com segurança

import express from 'express';
import { createHmac, timingSafeEqual } from 'crypto';
import Redis from 'ioredis';

const app = express();
const redis = new Redis(process.env.REDIS_URL);
const SECRET = process.env.VOOP_WEBHOOK_SECRET; // do dashboard

// IMPORTANTE: rawBody é necessário para verificar HMAC
app.use((req, _res, next) => {
  let data = '';
  req.setEncoding('utf8');
  req.on('data', (chunk) => (data += chunk));
  req.on('end', () => {
    req.rawBody = data;
    try {
      req.body = JSON.parse(data);
    } catch {
      req.body = null;
    }
    next();
  });
});

function verifySignature(req) {
  const header = req.headers['x-voop-signature'];
  if (!header) throw new Error('Missing signature header');

  const parts = Object.fromEntries(
    header.split(',').map((p) => p.split('=')),
  );
  const timestamp = parseInt(parts.t, 10);
  const provided = parts.v1;

  // Replay protection: 5 min
  if (Math.abs(Date.now() / 1000 - timestamp) > 300) {
    throw new Error('Timestamp too old or in future');
  }

  const expected = createHmac('sha256', SECRET)
    .update(`${timestamp}.${req.rawBody}`)
    .digest('hex');

  if (provided.length !== expected.length) {
    throw new Error('Signature length mismatch');
  }
  if (!timingSafeEqual(Buffer.from(provided, 'hex'), Buffer.from(expected, 'hex'))) {
    throw new Error('Invalid signature');
  }
}

async function ensureNotProcessed(eventId) {
  const key = `voop:webhook:seen:${eventId}`;
  // SETNX retorna 1 se foi setado (não existia), 0 se já existia
  const result = await redis.set(key, '1', 'EX', 7 * 24 * 60 * 60, 'NX');
  if (result === null) {
    console.log(`Skip duplicate event ${eventId}`);
    return false;
  }
  return true;
}

app.post('/voop/webhook', async (req, res) => {
  try {
    verifySignature(req);
  } catch (err) {
    console.warn('Signature verification failed:', err.message);
    return res.status(401).json({ error: err.message });
  }

  const eventId = req.headers['x-voop-event-id'];
  if (!(await ensureNotProcessed(eventId))) {
    return res.json({ skipped: 'duplicate' });
  }

  const { type, data } = req.body;

  // Despachar por tipo
  switch (type) {
    case 'item.created':
    case 'item.updated':
      console.log(`Item ${data.externalId} → ${type}`);
      // sua lógica aqui
      break;

    case 'item.deleted':
      console.log(`Deleted ${data.externalId}`);
      break;

    case 'stock.adjusted':
      console.log(`Stock change on ${data.itemId}: ${data.quantity} (total now ${data.totalStock})`);
      break;

    case 'media.ingested':
      console.log(`Media ${data.sourceUrl} stored as asset ${data.assetId}`);
      break;

    case 'media.ingestion_failed':
      console.error(`Media FAILED ${data.sourceUrl}: ${data.error}`);
      // alertar time de catálogo
      break;

    case 'import.completed':
      console.log(`Import ${data.jobId} → ${data.status}`, data.counts);
      break;

    default:
      console.log(`Unknown event: ${type}`);
  }

  // ✅ SEMPRE responda 2xx em < 5s. Processamento pesado vai para fila.
  res.json({ received: true });
});

app.listen(3000, () => console.log('Voop webhook listener on :3000'));

case 'item.updated':
  await myQueue.add('voop-item-updated', data); // BullMQ, SQS, etc.
  break;