// WRONG: Body already parsed
app.use(express.json());
app.post('/webhooks/stripe', stripeWebhook); // ❌ Body is already parsed

// CORRECT: Use raw body for webhook endpoint
app.post('/webhooks/stripe',
  express.raw({ type: 'application/json' }), // ✅ Raw body
  stripeWebhook
);
app.use(express.json()); // Parse JSON for other routes

const stripeWebhook = (req: Request, res: Response) => {
  const sig = req.headers['stripe-signature'];
  const webhookSecret = process.env.STRIPE_WEBHOOK_SECRET;

  try {
    // req.body must be the raw buffer, not parsed JSON
    const event = stripe.webhooks.constructEvent(
      req.body, // Raw buffer
      sig,
      webhookSecret
    );
    // Handle event...
  } catch (err) {
    console.error('Webhook signature verification failed:', err.message);
    return res.status(400).send(`Webhook Error: ${err.message}`);
  }
};

// main.ts
const app = await NestFactory.create(AppModule, {
  rawBody: true, // Enable raw body access
});

// webhook.controller.ts
@Post('stripe')
async handleStripeWebhook(
  @Headers('stripe-signature') signature: string,
  @Req() req: RawBodyRequest<Request>,
) {
  const event = this.stripe.webhooks.constructEvent(
    req.rawBody, // Use rawBody, not body
    signature,
    this.webhookSecret,
  );
}