dokuPayment controller nodejs express

exports.dokuPayment = async (req, res) => {

  // doku payment gateway
  const DOKU_BASE_URL = 'https://api-sandbox.doku.com';
  const client_id = "BRN-xxxx-xxxxxxxxxxx"; // Ganti dengan Client-ID Anda
  const secret_key = "SK-xxxxxxxxxxxx"; // Ganti dengan Secret-Key Anda
  const url = "/checkout/v1/payment";

  // Fungsi untuk mendapatkan timestamp terbaru
  function getCurrentTimestamp() {
    return new Date().toISOString().slice(0, 19) + "Z";
  }

  // Fungsi untuk menghasilkan Digest
  function generateDigest(jsonBody) {
    let jsonStringHash256 = crypto
      .createHash("sha256")
      .update(jsonBody, "utf-8")
      .digest();
    let bufferFromJsonStringHash256 = Buffer.from(jsonStringHash256);
    return bufferFromJsonStringHash256.toString("base64");
  }

  // Fungsi untuk menghasilkan Signature
  function generateSignature(clientId, requestId, requestTarget, digest, secret) {
    let requestTimestamp = getCurrentTimestamp();
    let componentSignature = `Client-Id:${clientId}\n`;
    componentSignature += `Request-Id:${requestId}\n`;
    componentSignature += `Request-Timestamp:${requestTimestamp}\n`;
    componentSignature += `Request-Target:${requestTarget}`;
    if (digest) {
      componentSignature += `\nDigest:${digest}`;
    }

    let hmac256Value = crypto
      .createHmac("sha256", secret)
      .update(componentSignature.toString())
      .digest();
    let bufferFromHmac256Value = Buffer.from(hmac256Value);
    let signature = bufferFromHmac256Value.toString("base64");
    return "HMACSHA256=" + signature;
  }

  const request_id = '12'; // Generate unique request ID
  const requestTimestamp = getCurrentTimestamp();

  let jsonBody = JSON.stringify({
    order: {
      amount: 1000,
      // invoice_number: `INV-${requestTimestamp}`,
      invoice_number: 'INV-100',
      currency: "IDR",
      callback_url: "https://xxx.id/", // Ganti dengan URL callback Anda
      callback_url_cancel: "https://xxx.id/", // Ganti dengan URL callback Anda
    },
    payment: {
      payment_due_date: 2,
      // payment_method_types: ["QRIS"],
    },
    customer: {
      id: "1",
      name: "Zolanda",
      email: "zolanda@example.com",
      phone: "628121212121",
      address: "Jl. Imam Bonjol No 14",
      country: "ID",
    },
  });

  let digest = generateDigest(jsonBody);
  let headerSignature = generateSignature(client_id, request_id, url, digest, secret_key);

  const headers = {
    "Client-Id": client_id,
    "Request-Id": request_id,
    "Request-Timestamp": requestTimestamp,
    Signature: headerSignature,
    "Content-Type": "application/json",
  };

  try {
    const response = await fetch(DOKU_BASE_URL + url, {
      method: "POST",
      headers: headers,
      body: jsonBody,
    });

    const data = await response.json();
    if (response.ok) {
      res.json(data);
    } else {
      res.status(response.status).json(data);
    }
  } catch (error) {
    res.status(500).json({ error: error.message });
  }

};