const crypto = require('crypto');

function createHmacSignature(method, url, timestamp, body, apiSecret) {
    // Construct payload
    const payload = `${method.toUpperCase()}${url}${timestamp}${body}`;
    
    // Create signature
    const signature = crypto
        .createHmac('sha256', apiSecret)
        .update(payload)
        .digest('hex');
    
    return signature;
}

// Example usage
const signature = createHmacSignature(
    'POST',
    'https://apis.hopnow.io/v1/customers/cus_123/accounts',
    '1640995200',
    '{"name":"Trading Account"}',
    'your_secret_key'
);