import {
  startAuthentication,
  startRegistration,
  bufferToBase64URLString,
} from '@simplewebauthn/browser';
import { PublicKeyCredentialCreationOptionsJSON } from '@simplewebauthn/typescript-types';
import {
  decodeRegistrationCredential,
  decodeAuthenticationCredential,
} from '@prex0/prex-webauthn';
import { decodeAbiParameters, Hex, toBytes } from 'viem';

function getChallenge() {
  const array = new Uint8Array(32);

  crypto.getRandomValues(array);

  return bufferToBase64URLString(array.buffer);
}

export async function registerByWebAuthn(
  options: PublicKeyCredentialCreationOptionsJSON
) {
  const response = await startRegistration(options);
  const decodedCred = await decodeRegistrationCredential(response);

  return {
    response,
    decodedCred,
  };
}

export async function getCredentialID() {
  const credential = await startAuthentication({
    challenge: getChallenge(),
    userVerification: 'required',
  });

  return credential.id;
}

export async function signByPasskey(message: string, passkeyIds?: string[]) {
  const challenge = bufferToBase64URLString(getChallengeBuffer(message));

  const credential = await startAuthentication({
    challenge: challenge,
    userVerification: 'required',
    allowCredentials: passkeyIds?.map((id) => ({
      id: id,
      type: 'public-key',
    })),
  });

  const decodedCred = decodeAuthenticationCredential(credential);

  return {
    userHandle: decodedCred.userHandle,
    name: '',
    signature: decodedCred.signature,
  };
}

function getChallengeBuffer(message: string) {
  return new Uint8Array(toBytes(message)).buffer;
}

// decode publicKey for Smart Wallet
export function decodePublicKey(publicKey: Hex) {
  return decodeAbiParameters(
    [{ type: 'uint256' }, { type: 'uint256' }],
    publicKey
  );
}