/**
 * Example to refresh tokens using https://github.com/auth0/node-jsonwebtoken
 * It was requested to be introduced at as part of the jsonwebtoken library,
 * since we feel it does not add too much value but it will add code to mantain
 * we won't include it.
 *
 * I create this gist just to help those who want to auto-refresh JWTs.
 */

const jwt = require('jwt');

function TokenGenerator (secretOrPrivateKey, secretOrPublicKey, options) {
  this.secretOrPrivateKey = secretOrPrivateKey;
  this.secretOrPublicKey = secretOrPublicKey;
  this.options = options; //algorithm + keyid + noTimestamp + expiresIn + notBefore
}

TokenGenerator.prototype.sign = function(payload, signOptions) {
  const jwtSignOptions = Object.assign({}, signOptions, this.options);
  return jwt.sign(payload, this.secretOrPrivateKey, jwtSignOptions);
}

// refreshOptions.verify = options you would use with verify function
// refreshOptions.jwtid = contains the id for the new token
TokenGenerator.prototype.refresh = function(token, refreshOptions) {
  const payload = jwt.verify(token, this.secretOrPrivateKey, refreshOptions.verify);
  delete payload.iat;
  delete payload.exp;
  delete payload.nbf;
  delete payload.jti; //We are generating a new token, if you are using jwtid during signing,
  // Since the first signing converted all neede options into claims, they are already in the payload
  const jwtSignOptions = Object.assign({ jwtid: refreshOptions.jwtid }, this.options);
  return jwt.sign(payload, this.secretOrPrivateKey, jwtSignOptions);
}

module.exports = TokenGenerator;