import crypto from 'crypto';

function verifyWebhookSignature(rawBody, signature, timestamp, secret) {
  const signedPayload = `${timestamp}.${rawBody}`;
  const computed = crypto
    .createHmac('sha256', secret)
    .update(signedPayload, 'utf8')
    .digest('hex');

  return crypto.timingSafeEqual(
    Buffer.from(computed, 'hex'),
    Buffer.from(signature, 'hex')
  );
}

// Dans votre gestionnaire de webhook :
const rawBody = req.body; // corps brut de la requête sous forme de chaîne
const signature = req.headers['x-emailit-signature'];
const timestamp = req.headers['x-emailit-timestamp'];
const secret = process.env.WEBHOOK_SIGNING_SECRET;

// Protection contre les attaques par rejeu (tolérance de 5 minutes)
const age = Math.floor(Date.now() / 1000) - parseInt(timestamp, 10);
if (age > 300) {
  return res.status(401).send('Requête trop ancienne');
}

if (!verifyWebhookSignature(rawBody, signature, timestamp, secret)) {
  return res.status(401).send('Signature invalide');
}

import hmac
import hashlib
import time

def verify_webhook_signature(raw_body, signature, timestamp, secret):
    signed_payload = f"{timestamp}.{raw_body}"
    computed = hmac.new(
        secret.encode('utf-8'),
        signed_payload.encode('utf-8'),
        hashlib.sha256
    ).hexdigest()

    return hmac.compare_digest(computed, signature)

# Protection contre les attaques par rejeu (tolérance de 5 minutes)
age = int(time.time()) - int(timestamp)
if age > 300:
    raise ValueError("Requête trop ancienne")

function verifyWebhookSignature(
    string $rawBody,
    string $signature,
    string $timestamp,
    string $secret
): bool {
    $signedPayload = "{$timestamp}.{$rawBody}";
    $computed = hash_hmac('sha256', $signedPayload, $secret);
    return hash_equals($computed, $signature);
}

// Protection contre les attaques par rejeu (tolérance de 5 minutes)
$age = time() - intval($timestamp);
if ($age > 300) {
    http_response_code(401);
    exit('Requête trop ancienne');
}

require 'openssl'

def verify_webhook_signature(raw_body, signature, timestamp, secret)
  signed_payload = "#{timestamp}.#{raw_body}"
  computed = OpenSSL::HMAC.hexdigest('SHA256', secret, signed_payload)
  Rack::Utils.secure_compare(computed, signature)
end

# Protection contre les attaques par rejeu (tolérance de 5 minutes)
age = Time.now.to_i - timestamp.to_i
raise 'Requête trop ancienne' if age > 300

import (
    "crypto/hmac"
    "crypto/sha256"
    "encoding/hex"
    "fmt"
    "time"
    "strconv"
)

func verifyWebhookSignature(rawBody, signature, timestamp, secret string) bool {
    signedPayload := fmt.Sprintf("%s.%s", timestamp, rawBody)
    mac := hmac.New(sha256.New, []byte(secret))
    mac.Write([]byte(signedPayload))
    computed := hex.EncodeToString(mac.Sum(nil))
    return hmac.Equal([]byte(computed), []byte(signature))
}

// Protection contre les attaques par rejeu (tolérance de 5 minutes)
ts, _ := strconv.ParseInt(timestamp, 10, 64)
if time.Now().Unix()-ts > 300 {
    // rejeter la requête
}