import { Hex, slice, toBytes, toHex } from 'viem';
import { privateKeyToAddress } from 'viem/accounts';

export function generateKey() {
  const array = new Uint8Array(32);
  crypto.getRandomValues(array);
  return toHex(array);
}

export function generateSecret() {
  const secret = generateKey();

  const publicKey = privateKeyToAddress(secret);

  return { secret, publicKey };
}

export function generateShortCode() {
  const array = new Uint8Array(16);
  crypto.getRandomValues(array);
  const hexCode = toHex(array);

  return hexCode;
}

export async function encryptByTmpSecret(secret: Hex, hexData: Hex) {
  const { key, iv } = secretToKeyAndIV(secret);

  const secretKey = await crypto.subtle.importKey(
    'raw',
    key,
    'AES-CTR',
    false,
    ['encrypt', 'decrypt']
  );

  const buf = await crypto.subtle.encrypt(
    {
      name: 'AES-CTR',
      counter: iv,
      length: 128,
    },
    secretKey,
    Buffer.from(toBytes(hexData))
  );

  return toHex(new Uint8Array(buf));
}

export async function decryptByTmpSecret(secret: Hex, hexData: Hex) {
  const { key, iv } = secretToKeyAndIV(secret);

  const secretKey = await crypto.subtle.importKey(
    'raw',
    key,
    'AES-CTR',
    false,
    ['encrypt', 'decrypt']
  );

  const decrypted = await crypto.subtle.decrypt(
    { name: 'AES-CTR', counter: iv, length: 128 },
    secretKey,
    Buffer.from(toBytes(hexData))
  );

  return toHex(new Uint8Array(decrypted));
}

function secretToKeyAndIV(secret: Hex) {
  return {
    key: Buffer.from(toBytes(slice(secret, 0, 16))),
    iv: Buffer.from(toBytes(slice(secret, 16, 32))),
  };
}