import forge from 'node-forge';
interface EncryptTabaPayCardDataParams {
  keyData: string; // public key data for TabaPay
  cardNumber: string; // user input debit card number
  expDate: string; // user input expiration date for debit card
}
export const base64EncodeUrl = (s: string) => {
  return s
    .replace(/\+/g, '-')
    .replace(/\//g, '_')
    .replace(/=+$/, '');
};
export const base64DecodeUrl = (s: string) => {
  const str = `${s}===`.slice(0, s.length + (s.length % 4));
  return str.replace(/-/g, '+').replace(/_/g, '/');
};
export const formatPemPublicKey = (str: string) => {
  return `-----BEGIN PUBLIC KEY-----\r\n${str}\r\n-----END PUBLIC KEY-----\r\n`;
};
/**
 * Encrypts card data into base 64 URL format for TabaPay
 * @param EncryptTabaPayCardDataParams TabaPay public key data and user's debit
 * card number & expiration date
 */
export const encryptTabaPayCardData = ({
  keyData,
  cardNumber,
  expDate,
}: EncryptTabaPayCardDataParams): string => {
  // decode the base 64 url encoded key data
  const decodedKey = base64DecodeUrl(keyData);
  // format the decoded key using PEM format
  const pemKey = formatPemPublicKey(decodedKey);
  // use forge to get public key
  const publicKey = forge.pki.publicKeyFromPem(pemKey);
  const cardData = `${cardNumber}|${expDate}|`;
  // encrypt the card data
  const encrypted = publicKey.encrypt(cardData, 'RSA-OAEP', {
    md: forge.md.sha256.create(),
    mgf1: {
      md: forge.md.sha256.create(),
    },
  });
  // encode encrypted data to base 64 url format
  const encryptedBase64 = forge.util.encode64(encrypted);
  return base64EncodeUrl(encryptedBase64);
};