import crypto, { KeyLike, KeyObject } from "crypto";
import util from "util";
import type { TapoDeviceKey } from "./types";

const RSA_CIPHER_ALGORITHM = "rsa";
const AES_CIPHER_ALGORITHM = "aes-128-cbc";
const PASSPHRASE = "top secret";

export const generateKeyPair = async () => {
  const RSA_OPTIONS = {
    modulusLength: 1024,
    publicKeyEncoding: {
      type: "spki",
      format: "pem",
    },
    privateKeyEncoding: {
      type: "pkcs1",
      format: "pem",
      cipher: "aes-256-cbc",
      passphrase: PASSPHRASE,
    },
  };
  const generateKeyPair = util.promisify(crypto.generateKeyPair);
  // @ts-ignore
  return await generateKeyPair(RSA_CIPHER_ALGORITHM, RSA_OPTIONS);
};

export const encrypt = (data: any, deviceKey: TapoDeviceKey): string => {
  var cipher = crypto.createCipheriv(
    AES_CIPHER_ALGORITHM,
    deviceKey.key,
    deviceKey.iv,
  );
  var ciphertext = cipher.update(Buffer.from(JSON.stringify(data)));
  return Buffer.concat([ciphertext, cipher.final()]).toString("base64");
};

export const decrypt = (data: string, deviceKey: TapoDeviceKey): any => {
  var cipher = crypto.createDecipheriv(
    AES_CIPHER_ALGORITHM,
    deviceKey.key,
    deviceKey.iv,
  );
  var ciphertext = cipher.update(Buffer.from(data, "base64"));
  return JSON.parse(Buffer.concat([ciphertext, cipher.final()]).toString());
};

export const readDeviceKey = (
  pemKey: string,
  privateKey: KeyLike,
): Buffer => {
  const keyBytes = Buffer.from(pemKey, "base64");
  const deviceKey = crypto.privateDecrypt(
    {
      key: privateKey,
      padding: crypto.constants.RSA_PKCS1_PADDING,
      passphrase: PASSPHRASE,
    },
    keyBytes,
  );

  return deviceKey;
};

export const base64Encode = (data: string): string => {
  return Buffer.from(data).toString("base64");
};

export const base64Decode = (data: string): string => {
    if (!data) return ''
  return Buffer.from(data, "base64").toString();
};

export const shaDigest = (data: string): string => {
  var shasum = crypto.createHash("sha1");
  shasum.update(data);
  return shasum.digest("hex");
};