updateAuthority.ts

import {
  AuthorityType,
  getSetAuthorityInstruction,
  getUpdateTokenMetadataUpdateAuthorityInstruction,
  TOKEN_2022_PROGRAM_ADDRESS,
} from 'gill/programs/token';
import type {
  Address,
  Instruction,
  FullTransaction,
  TransactionVersion,
  TransactionMessageWithFeePayer,
  TransactionSigner,
  Rpc,
  SolanaRpcApi,
} from 'gill';
import { createTransaction } from 'gill';

type AuthorityRole = AuthorityType | 'Metadata';

/**
 * Returns the appropriate instruction(s) to update the authority for a given mint and role.
 *
 * If the role is 'Metadata', this will return an instruction to update the metadata update authority.
 * Otherwise, it returns a set authority instruction for the specified authority type.
 *
 * @param input - The parameters for the authority update.
 * @param input.mint - The address of the mint whose authority is being updated.
 * @param input.role - The authority role to update ('Metadata' or an AuthorityType).
 * @param input.currentAuthority - The current authority signer.
 * @param input.newAuthority - The new authority address.
 * @returns An array containing the instruction to update the authority.
 */
export const getUpdateAuthorityInstructions = (input: {
  mint: Address;
  role: AuthorityRole;
  currentAuthority: TransactionSigner<string>;
  newAuthority: Address;
}): Instruction<string>[] => {
  if (input.role === 'Metadata') {
    return [
      getUpdateTokenMetadataUpdateAuthorityInstruction(
        {
          metadata: input.mint,
          updateAuthority: input.currentAuthority,
          newUpdateAuthority: input.newAuthority,
        },
        {
          programAddress: TOKEN_2022_PROGRAM_ADDRESS,
        }
      ),
    ];
  }
  return [
    getSetAuthorityInstruction({
      owned: input.mint,
      owner: input.currentAuthority.address,
      newAuthority: input.newAuthority,
      authorityType: input.role,
    }),
  ];
};

/**
 * Creates a transaction to update the authority for a given mint and role.
 *
 * This function fetches the latest blockhash, builds the appropriate instruction(s)
 * using `getUpdateAuthorityInstructions`, and returns a full transaction ready to be signed and sent.
 *
 * @param input - The parameters for the authority update transaction.
 * @param input.rpc - The Solana RPC client.
 * @param input.payer - The transaction fee payer.
 * @param input.mint - The address of the mint whose authority is being updated.
 * @param input.role - The authority role to update ('Metadata' or an AuthorityType).
 * @param input.currentAuthority - The current authority signer.
 * @param input.newAuthority - The new authority address.
 * @returns A promise that resolves to the constructed full transaction.
 */
export const getUpdateAuthorityTransaction = async (input: {
  rpc: Rpc<SolanaRpcApi>;
  payer: TransactionSigner<string>;
  mint: Address;
  role: AuthorityRole;
  currentAuthority: TransactionSigner<string>;
  newAuthority: Address;
}): Promise<
  FullTransaction<TransactionVersion, TransactionMessageWithFeePayer>
> => {
  const instructions = getUpdateAuthorityInstructions(input);
  const { value: latestBlockhash } = await input.rpc
    .getLatestBlockhash()
    .send();

  return createTransaction({
    feePayer: input.payer,
    version: 'legacy',
    latestBlockhash,
    instructions,
  });
};