// Copyright 2017-2025 @polkadot/util-crypto authors & contributors
// SPDX-License-Identifier: Apache-2.0

import { getSharedSecret } from '@scure/sr25519';

import { u8aToU8a } from '@pezkuwi/util';

/**
 * @name sr25519Agreement
 * @description Key agreement between other's public key and self secret key
 */
export function sr25519Agreement (secretKey: string | Uint8Array, publicKey: string | Uint8Array): Uint8Array {
  const secretKeyU8a = u8aToU8a(secretKey);
  const publicKeyU8a = u8aToU8a(publicKey);

  if (publicKeyU8a.length !== 32) {
    throw new Error(`Invalid publicKey, received ${publicKeyU8a.length} bytes, expected 32`);
  } else if (secretKeyU8a.length !== 64) {
    throw new Error(`Invalid secretKey, received ${secretKeyU8a.length} bytes, expected 64`);
  }

  return getSharedSecret(secretKeyU8a, publicKeyU8a);
}
