import { box, randomBytes } from 'tweetnacl';
import {
  decode as decodeUTF8,
  encode as encodeUTF8,
} from "@stablelib/utf8";
import {
  decode as decodeBase64,
  encode as encodeBase64,
} from "@stablelib/base64";
const newNonce = () => randomBytes(box.nonceLength);
export const generateKeyPair = () => box.keyPair();
export const encrypt = (
  secretOrSharedKey: Uint8Array,
  json: any,
  key?: Uint8Array
) => {
  const nonce = newNonce();
  const messageUint8 = encodeUTF8(JSON.stringify(json));
  const encrypted = key
    ? box(messageUint8, nonce, key, secretOrSharedKey)
    : box.after(messageUint8, nonce, secretOrSharedKey);
  const fullMessage = new Uint8Array(nonce.length + encrypted.length);
  fullMessage.set(nonce);
  fullMessage.set(encrypted, nonce.length);
  const base64FullMessage = encodeBase64(fullMessage);
  return base64FullMessage;
};
export const decrypt = (
  secretOrSharedKey: Uint8Array,
  messageWithNonce: string,
  key?: Uint8Array
) => {
  const messageWithNonceAsUint8Array = decodeBase64(messageWithNonce);
  const nonce = messageWithNonceAsUint8Array.slice(0, box.nonceLength);
  const message = messageWithNonceAsUint8Array.slice(
    box.nonceLength,
    messageWithNonce.length
  );
  const decrypted = key
    ? box.open(message, nonce, key, secretOrSharedKey)
    : box.open.after(message, nonce, secretOrSharedKey);
  if (!decrypted) {
    throw new Error('Could not decrypt message');
  }
  const base64DecryptedMessage = decodeUTF8(decrypted);
  return JSON.parse(base64DecryptedMessage);
};
const obj = { hello: 'world' };
const pairA = generateKeyPair();
const pairB = generateKeyPair();
const sharedA = box.before(pairB.publicKey, pairA.secretKey);
const sharedB = box.before(pairA.publicKey, pairB.secretKey);
const encrypted = encrypt(sharedA, obj);
const decrypted = decrypt(sharedB, encrypted);
console.log(obj, encrypted, decrypted);