import { Platform } from './Platform';

/**
 *
 * @param {Platform} platform
 * @param {AbstractStateTransition} stateTransition
 * @param {Identity} identity
 * @param {number} [keyIndex]
 * @return {AbstractStateTransition}
 */
export async function signStateTransition(
  platform: Platform,
  stateTransition: any,
  identity: any,
  keyIndex: number = 0,
): Promise<any> {
  const { client } = platform;

  const account = await client.getWalletAccount();

  const { privateKey } = account.identities.getIdentityHDKeyById(
    identity.getId().toString(),
    keyIndex,
  );

  await stateTransition.sign(
    identity.getPublicKeyById(keyIndex),
    privateKey.toBuffer(),
  );

  return stateTransition;
}