import crypto from "crypto"

function createPayfastHeaders(data) {
  // remember live and sandbox merchant_id and passphrase are different
  const merchant_id = "your_merchant_id"
  const passphrase = "your_pass_phrase"

  data = {
    ...data,
    passphrase,
  }

  const headers = {
    "merchant-id": merchant_id,
    "version": "v1",
    "timestamp": (new Date()).toISOString().split('.')[0],
    "signature": ""
  }

  const req_headers = new Headers()
  Object.keys(headers).forEach(key => {
    req_headers.append(key, headers[key])
  })

  const signature_data = {...data, ...headers}
  let signature_uri = "";
  Object.keys(signature_data).sort().forEach(key => {
    if (key !== "signature") {
      signature_uri += `${key}=${encodeURIComponent(signature_data[key]).replace(/%20/g, '+')}&`
    }
  });

  // Remove the last '&'
  signature_uri = signature_uri.substring(0, signature_uri.length - 1);

  const signature = crypto.createHash("md5").update(signature_uri).digest("hex");
  req_headers.set("signature", signature)
  req_headers.append("Content-Type", "application/json") // <- important

  return req_headers
}

async function createRefund(payment_id, refund_params) {
  const headers = createPayfastHeaders(refund_params)

  const url = `https://api.payfast.co.za/refunds/${payment_id}?testing=true`; // <- add testing true for sandbox testing
  const response = await fetch(url, {
    method: "POST",
    headers: headers,
    body: JSON.stringify(refund_params)
  });

  return await response.json();
}

const refund = await createRefund("2120314", {
  amount: 1000,
  reason: "stock",
  notify_buyer: 0
});