/**
 * Signs a transaction using the PKP's public key.
 * @param {Object} params - The parameters object
 * @param {string} params.pkpPublicKey - The PKP's public key
 * @param {any} params.tx - The transaction to sign
 * @param {string} params.sigName - The name of the signature
 * @returns {Promise<string>} The signed transaction.
 */
export const signTx = async ({
  sigName,
  pkpPublicKey,
  tx,
}: {
  sigName: string;
  pkpPublicKey: string;
  tx: any;
}): Promise<string> => {
  console.log(`Signing TX: ${sigName}`);
  const pkForLit = pkpPublicKey.startsWith("0x")
    ? pkpPublicKey.slice(2)
    : pkpPublicKey;

  const sig = await Lit.Actions.signAndCombineEcdsa({
    toSign: ethers.utils.arrayify(
      ethers.utils.keccak256(ethers.utils.serializeTransaction(tx))
    ),
    publicKey: pkForLit,
    sigName,
  });

  return ethers.utils.serializeTransaction(
    tx,
    ethers.utils.joinSignature({
      r: "0x" + JSON.parse(sig).r.substring(2),
      s: "0x" + JSON.parse(sig).s,
      v: JSON.parse(sig).v,
    })
  );
};