Signing API requests

import crypto from 'crypto';
import { sortObjectAlphabetically } from "./sort.js";

function sha512Sign(message, secret) {
  return crypto.createHmac('sha512', secret).update(message).digest('hex');
}

// Get the timestamp (in seconds) and pass it to the header as 'Request-Timestamp'
const timestamp = Math.floor(Date.now() / 1000);
const requestPath = "/v1/payouts";
const API_SECRET = "YOUR_API_SECRET"; // replace these with your actual API secret value

// Get the request body 
let body = {
  "amount":{
    "currency":"NGN",
    "value":10000
  },
  "bankId":"bank_538ed2056326432ba8e6853b613997bb",
  "callbackUrl":"https://webhook.site/99a59e8a-bd0b-485d-8249-fccb5eb62e27",
  "destinationAccountNumber":"9845648577",
  "metadata":{
    "category":"transfer"
  },
  "narration":"zapped",
  "reference":"trx_fWQ7b31pbs5mmT3k3qfb46"
};

// Sort the body alphabetically
body = sortObjectAlphabetically(body);

// Create the body hash to be passed as payload
const bodyHash = sha512Sign(JSON.stringify(body), API_SECRET);

// Concatenate the string to sign
const stringToSign = `${requestPath}${bodyHash}${timestamp}`;

// Generate the Request-Signature value for the header
const signature = sha512Sign(stringToSign, API_SECRET);

console.log(`signature: ${signature}`);

export function sortObjectAlphabetically(obj) {
  if (!obj || typeof obj !== 'object' || Array.isArray(obj)) {
    return obj;
  }

  const sortedKeys = Object.keys(obj).sort();
  const sortedObj = {};

  // Add each property to the new object in alphabetical order
  sortedKeys.forEach(key => {
    // Recursively sort nested objects
    if (typeof obj[key] === 'object' && !Array.isArray(obj[key]) && obj[key] !== null) {
      sortedObj[key] = sortObjectAlphabetically(obj[key]);
    } else {
      sortedObj[key] = obj[key];
    }
  });

  return sortedObj;
}