KeyringController.ts

import type { TypedTransaction, TxData } from '@ethereumjs/tx';
import * as encryptorUtils from '@metamask/browser-passworder';
import HDKeyring from '@metamask/eth-hd-keyring';
import { normalize as normalizeToHex } from '@metamask/eth-sig-util';
import SimpleKeyring from '@metamask/eth-simple-keyring';
import { ObservableStore } from '@metamask/obs-store';
import { remove0x, isValidHexAddress, isObject } from '@metamask/utils';
import type {
  Hex,
  Json,
  Keyring,
  KeyringClass,
  Eip1024EncryptedData,
} from '@metamask/utils';
// TODO: Stop using `events`, and remove the notice about this from the README
// eslint-disable-next-line import/no-nodejs-modules
import { EventEmitter } from 'events';

import { KeyringType, KeyringControllerError } from './constants';
import {
  SerializedKeyring,
  KeyringControllerArgs,
  KeyringControllerState,
  KeyringControllerPersistentState,
} from './types';

const defaultKeyringBuilders = [
  keyringBuilderFactory(SimpleKeyring),
  keyringBuilderFactory(HDKeyring),
];

class KeyringController extends EventEmitter {
  keyringBuilders: { (): Keyring<Json>; type: string }[];

  public store: ObservableStore<KeyringControllerPersistentState>;

  public memStore: ObservableStore<KeyringControllerState>;

  public encryptor: any;

  public keyrings: Keyring<Json>[];

  public cacheEncryptionKey: boolean;

  public unsupportedKeyrings: SerializedKeyring[];

  public password?: string;

  constructor({
    keyringBuilders,
    cacheEncryptionKey,
    initState = {},
    encryptor = encryptorUtils,
  }: KeyringControllerArgs) {
    super();
    this.keyringBuilders = keyringBuilders
      ? defaultKeyringBuilders.concat(keyringBuilders)
      : defaultKeyringBuilders;
    this.store = new ObservableStore(initState);
    this.memStore = new ObservableStore({
      isUnlocked: false,
      keyringTypes: this.keyringBuilders.map(
        (keyringBuilder) => keyringBuilder.type,
      ),
      keyrings: [],
    });

    this.encryptor = encryptor;
    this.keyrings = [];
    this.unsupportedKeyrings = [];

    // This option allows the controller to cache an exported key
    // for use in decrypting and encrypting data without password
    this.cacheEncryptionKey = Boolean(cacheEncryptionKey);
  }

  /**
   * Full Update
   *
   * Emits the `update` event and @returns a Promise that resolves to
   * the current state.
   *
   * Frequently used to end asynchronous chains in this class,
   * indicating consumers can often either listen for updates,
   * or accept a state-resolving promise to consume their results.
   *
   * @returns The controller state.
   */
  fullUpdate() {
    this.emit('update', this.memStore.getState());
    return this.memStore.getState();
  }

  /**
   * =======================================
   * === Public Vault Management Methods ===
   * =======================================
   */

  /**
   * Create New Vault And Keychain
   *
   * Destroys any old encrypted storage,
   * creates a new encrypted store with the given password,
   * randomly creates a new HD wallet with 1 account,
   * faucets that account on the testnet.
   *
   * @fires KeyringController#unlock
   * @param password - The password to encrypt the vault with.
   * @returns A promise that resolves to the state.
   */
  async createNewVaultAndKeychain(
    password: string,
  ): Promise<KeyringControllerState> {
    this.password = password;

    await this.#createFirstKeyTree();
    this.#setUnlocked();
    return this.fullUpdate();
  }

  /**
   * CreateNewVaultAndRestore
   *
   * Destroys any old encrypted storage,
   * creates a new encrypted store with the given password,
   * creates a new HD wallet from the given seed with 1 account.
   *
   * @fires KeyringController#unlock
   * @param password - The password to encrypt the vault with.
   * @param seedPhrase - The BIP39-compliant seed phrase,
   * either as a string or Uint8Array.
   * @returns A promise that resolves to the state.
   */
  async createNewVaultAndRestore(
    password: string,
    seedPhrase: Uint8Array | string | number[],
  ): Promise<KeyringControllerState> {
    if (typeof password !== 'string') {
      throw new TypeError(KeyringControllerError.WrongPasswordType);
    }
    this.password = password;

    await this.#clearKeyrings();
    const keyring = await this.addNewKeyring(KeyringType.HD, {
      mnemonic: seedPhrase,
      numberOfAccounts: 1,
    });

    const [firstAccount] = await keyring.getAccounts();

    if (!firstAccount) {
      throw new Error(KeyringControllerError.NoFirstAccount);
    }
    this.#setUnlocked();
    return this.fullUpdate();
  }

  /**
   * Set Locked.
   * This method deallocates all secrets, and effectively locks MetaMask.
   *
   * @fires KeyringController#lock
   * @returns A promise that resolves to the state.
   */
  async setLocked(): Promise<KeyringControllerState> {
    delete this.password;

    // set locked
    this.memStore.putState({
      isUnlocked: false,
      keyrings: [],
    });

    // remove keyrings
    await this.#clearKeyrings();
    this.emit('lock');
    return this.fullUpdate();
  }

  /**
   * Submit password.
   *
   * Attempts to decrypt the current vault and load its keyrings
   * into memory.
   *
   * Temporarily also migrates any old-style vaults first, as well
   * (Pre MetaMask 3.0.0).
   *
   * @fires KeyringController#unlock
   * @param password - The keyring controller password.
   * @returns A promise that resolves to the state.
   */
  async submitPassword(password: string): Promise<KeyringControllerState> {
    this.keyrings = await this.unlockKeyrings(password);

    this.#setUnlocked();
    return this.fullUpdate();
  }

  /**
   * Submit Encryption Key.
   *
   * Attempts to decrypt the current vault and load its keyrings
   * into memory based on the vault and CryptoKey information.
   *
   * @fires KeyringController#unlock
   * @param encryptionKey - The encrypted key information used to decrypt the vault.
   * @param encryptionSalt - The salt used to generate the last key.
   * @returns A promise that resolves to the state.
   */
  async submitEncryptionKey(
    encryptionKey: string,
    encryptionSalt: string,
  ): Promise<KeyringControllerState> {
    this.keyrings = await this.unlockKeyrings(
      undefined,
      encryptionKey,
      encryptionSalt,
    );
    this.#setUnlocked();
    return this.fullUpdate();
  }

  /**
   * Verify Password
   *
   * Attempts to decrypt the current vault with a given password
   * to verify its validity.
   *
   * @param password - The vault password.
   */
  async verifyPassword(password: string): Promise<void> {
    const encryptedVault = this.store.getState().vault;
    if (!encryptedVault) {
      throw new Error(KeyringControllerError.VaultError);
    }
    await this.encryptor.decrypt(password, encryptedVault);
  }

  /**
   * =========================================
   * === Public Account Management Methods ===
   * =========================================
   */

  /**
   * Add New Account.
   *
   * Calls the `addAccounts` method on the given keyring,
   * and then saves those changes.
   *
   * @param selectedKeyring - The currently selected keyring.
   * @returns A Promise that resolves to the state.
   */
  async addNewAccount(
    selectedKeyring: Keyring<Json>,
  ): Promise<KeyringControllerState> {
    const accounts = await selectedKeyring.addAccounts(1);
    accounts.forEach((hexAccount) => {
      this.emit('newAccount', hexAccount);
    });

    await this.persistAllKeyrings();
    return this.fullUpdate();
  }

  /**
   * Export Account
   *
   * Requests the private key from the keyring controlling
   * the specified address.
   *
   * Returns a Promise that may resolve with the private key string.
   *
   * @param address - The address of the account to export.
   * @returns The private key of the account.
   */
  async exportAccount(address: string): Promise<string> {
    const keyring = await this.getKeyringForAccount(address);
    if (!keyring.exportAccount) {
      throw new Error(KeyringControllerError.UnsupportedExportAccount);
    }

    return await keyring.exportAccount(normalizeToHex(address) as Hex);
  }

  /**
   * Remove Account.
   *
   * Removes a specific account from a keyring
   * If the account is the last/only one then it also removes the keyring.
   *
   * @param address - The address of the account to remove.
   * @returns A promise that resolves if the operation was successful.
   */
  async removeAccount(address: Hex): Promise<KeyringControllerState> {
    const keyring = await this.getKeyringForAccount(address);

    // Not all the keyrings support this, so we have to check
    if (!keyring.removeAccount) {
      throw new Error(KeyringControllerError.UnsupportedRemoveAccount);
    }
    keyring.removeAccount(address);
    this.emit('removedAccount', address);

    const accounts = await keyring.getAccounts();
    // Check if this was the last/only account
    if (accounts.length === 0) {
      await this.removeEmptyKeyrings();
    }

    await this.persistAllKeyrings();
    return this.fullUpdate();
  }

  /**
   * Get Accounts
   *
   * Returns the public addresses of all current accounts
   * managed by all currently unlocked keyrings.
   *
   * @returns The array of accounts.
   */
  async getAccounts(): Promise<string[]> {
    const keyrings = this.keyrings || [];

    const keyringArrays = await Promise.all(
      keyrings.map(async (keyring) => keyring.getAccounts()),
    );
    const addresses = keyringArrays.reduce((res, arr) => {
      return res.concat(arr);
    }, []);

    // Cast to `Hex[]` here is safe here because `addresses` has no nullish
    // values, and `normalizeToHex` returns `Hex` unless given a nullish value
    return addresses.map(normalizeToHex) as Hex[];
  }

  /**
   * Get Keyring Class For Type
   *
   * Searches the current `keyringBuilders` array
   * for a Keyring builder whose unique `type` property
   * matches the provided `type`,
   * returning it if it exists.
   *
   * @param type - The type whose class to get.
   * @returns The class, if it exists.
   */
  getKeyringBuilderForType(
    type: string,
  ): { (): Keyring<Json>; type: string } | undefined {
    return this.keyringBuilders.find(
      (keyringBuilder) => keyringBuilder.type === type,
    );
  }

  /**
   * Update memStore Keyrings
   *
   * Updates the in-memory keyrings, without persisting.
   */
  async updateMemStoreKeyrings(): Promise<void> {
    const keyrings = await Promise.all(this.keyrings.map(displayForKeyring));
    this.memStore.updateState({ keyrings });
  }

  /**
   * ===========================================
   * === Public RPC Requests Routing Methods ===
   * ===========================================
   */

  /**
   * Sign Ethereum Transaction
   *
   * Signs an Ethereum transaction object.
   *
   * @param ethTx - The transaction to sign.
   * @param rawAddress - The transaction 'from' address.
   * @param opts - Signing options.
   * @returns The signed transaction object.
   */
  async signTransaction(
    ethTx: TypedTransaction,
    rawAddress: string,
    opts: Record<string, unknown> = {},
  ): Promise<TxData> {
    const address = normalizeToHex(rawAddress) as Hex;
    const keyring = await this.getKeyringForAccount(address);
    if (!keyring.signTransaction) {
      throw new Error(KeyringControllerError.UnsupportedSignTransaction);
    }

    return await keyring.signTransaction(address, ethTx, opts);
  }

  /**
   * Sign Message
   *
   * Attempts to sign the provided message parameters.
   *
   * @param msgParams - The message parameters to sign.
   * @param msgParams.from - From address.
   * @param msgParams.data - The message to sign.
   * @param opts - Additional signing options.
   * @returns The raw signature.
   */
  async signMessage(
    msgParams: {
      from: string;
      data: string;
    },
    opts: Record<string, unknown> = {},
  ): Promise<string> {
    const address = normalizeToHex(msgParams.from) as Hex;
    const keyring = await this.getKeyringForAccount(address);
    if (!keyring.signMessage) {
      throw new Error(KeyringControllerError.UnsupportedSignMessage);
    }

    return await keyring.signMessage(address, msgParams.data, opts);
  }

  /**
   * Sign Personal Message
   *
   * Attempts to sign the provided message parameters.
   * Prefixes the hash before signing per the personal sign expectation.
   *
   * @param msgParams - The message parameters to sign.
   * @param msgParams.from - From address.
   * @param msgParams.data - The message to sign.
   * @param opts - Additional signing options.
   * @returns The raw signature.
   */
  async signPersonalMessage(
    msgParams: {
      from: string;
      data: string;
    },
    opts: Record<string, unknown> = {},
  ): Promise<string> {
    const address = normalizeToHex(msgParams.from) as Hex;
    const keyring = await this.getKeyringForAccount(address);
    if (!keyring.signPersonalMessage) {
      throw new Error(KeyringControllerError.UnsupportedSignPersonalMessage);
    }

    const normalizedData = normalizeToHex(msgParams.data) as Hex;

    return await keyring.signPersonalMessage(address, normalizedData, opts);
  }

  /**
   * Get encryption public key
   *
   * Get encryption public key for using in encrypt/decrypt process.
   *
   * @param address - The address to get the encryption public key for.
   * @param opts - Additional encryption options.
   * @returns The public key.
   */
  async getEncryptionPublicKey(
    address: string,
    opts: Record<string, unknown> = {},
  ): Promise<string> {
    const normalizedAddress = normalizeToHex(address) as Hex;
    const keyring = await this.getKeyringForAccount(address);
    if (!keyring.getEncryptionPublicKey) {
      throw new Error(KeyringControllerError.UnsupportedGetEncryptionPublicKey);
    }

    return await keyring.getEncryptionPublicKey(normalizedAddress, opts);
  }

  /**
   * Decrypt Message
   *
   * Attempts to decrypt the provided message parameters.
   *
   * @param msgParams - The decryption message parameters.
   * @param msgParams.from - The address of the account you want to use to decrypt the message.
   * @param msgParams.data - The encrypted data that you want to decrypt.
   * @returns The raw decryption result.
   */
  async decryptMessage(msgParams: {
    from: string;
    data: Eip1024EncryptedData;
  }): Promise<string> {
    const address = normalizeToHex(msgParams.from) as Hex;
    const keyring = await this.getKeyringForAccount(address);
    if (!keyring.decryptMessage) {
      throw new Error(KeyringControllerError.UnsupportedDecryptMessage);
    }

    return keyring.decryptMessage(address, msgParams.data);
  }

  /**
   * Sign Typed Data.
   *
   * @see {@link https://github.com/ethereum/EIPs/pull/712#issuecomment-329988454|EIP712}.
   * @param msgParams - The message parameters to sign.
   * @param msgParams.from - From address.
   * @param msgParams.data - The data to sign.
   * @param opts - Additional signing options.
   * @returns The raw signature.
   */
  async signTypedMessage(
    msgParams: {
      from: string;
      data: Record<string, unknown> | Record<string, unknown>[];
    },
    opts: Record<string, unknown> = { version: 'V1' },
  ): Promise<string> {
    // Cast to `Hex` here is safe here because `msgParams.from` is not nullish.
    // `normalizeToHex` returns `Hex` unless given a nullish value.
    const address = normalizeToHex(msgParams.from) as Hex;
    const keyring = await this.getKeyringForAccount(address);
    if (!keyring.signTypedData) {
      throw new Error(KeyringControllerError.UnsupportedSignTypedMessage);
    }

    // Looks like this is not well defined in the Keyring interface since
    // our tests show that we should be able to pass an array.
    // @ts-expect-error Missing other required permission types.
    return keyring.signTypedData(address, msgParams.data, opts);
  }

  /**
   * Gets the app key address for the given Ethereum address and origin.
   *
   * @param rawAddress - The Ethereum address for the app key.
   * @param origin - The origin for the app key.
   * @returns The app key address.
   */
  async getAppKeyAddress(rawAddress: string, origin: string): Promise<string> {
    const address = normalizeToHex(rawAddress) as Hex;
    const keyring = await this.getKeyringForAccount(address);
    if (!keyring.getAppKeyAddress) {
      throw new Error(KeyringControllerError.UnsupportedGetAppKeyAddress);
    }

    return keyring.getAppKeyAddress(address, origin);
  }

  /**
   * Exports an app key private key for the given Ethereum address and origin.
   *
   * @param rawAddress - The Ethereum address for the app key.
   * @param origin - The origin for the app key.
   * @returns The app key private key.
   */
  async exportAppKeyForAddress(
    rawAddress: string,
    origin: string,
  ): Promise<string> {
    const address = normalizeToHex(rawAddress) as Hex;
    const keyring = await this.getKeyringForAccount(address);
    if (!keyring.exportAccount) {
      throw new Error(KeyringControllerError.UnsupportedExportAppKeyForAddress);
    }
    return keyring.exportAccount(address, { withAppKeyOrigin: origin });
  }

  /**
   * =========================================
   * === Public Keyring Management Methods ===
   * =========================================
   */

  /**
   * Add New Keyring
   *
   * Adds a new Keyring of the given `type` to the vault
   * and the current decrypted Keyrings array.
   *
   * All Keyring classes implement a unique `type` string,
   * and this is used to retrieve them from the keyringBuilders array.
   *
   * @param type - The type of keyring to add.
   * @param opts - The constructor options for the keyring.
   * @returns The new keyring.
   */
  async addNewKeyring(type: string, opts?: unknown): Promise<Keyring<Json>> {
    const keyring = await this.#newKeyring(type, opts);

    if (!keyring) {
      throw new Error(KeyringControllerError.NoKeyring);
    }

    if (type === KeyringType.HD && (!isObject(opts) || !opts.mnemonic)) {
      if (!keyring.generateRandomMnemonic) {
        throw new Error(
          KeyringControllerError.UnsupportedGenerateRandomMnemonic,
        );
      }

      keyring.generateRandomMnemonic();
      await keyring.addAccounts(1);
    }

    const accounts = await keyring.getAccounts();
    await this.checkForDuplicate(type, accounts);

    this.keyrings.push(keyring);
    await this.persistAllKeyrings();

    this.fullUpdate();

    return keyring;
  }

  /**
   * Remove empty keyrings.
   *
   * Loops through the keyrings and removes the ones with empty accounts
   * (usually after removing the last / only account) from a keyring.
   */
  async removeEmptyKeyrings(): Promise<void> {
    const validKeyrings: Keyring<Json>[] = [];

    // Since getAccounts returns a Promise
    // We need to wait to hear back form each keyring
    // in order to decide which ones are now valid (accounts.length > 0)

    await Promise.all(
      this.keyrings.map(async (keyring: Keyring<Json>) => {
        const accounts = await keyring.getAccounts();
        if (accounts.length > 0) {
          validKeyrings.push(keyring);
        } else {
          await this.#destroyKeyring(keyring);
        }
      }),
    );
    this.keyrings = validKeyrings;
  }

  /**
   * Checks for duplicate keypairs, using the the first account in the given
   * array. Rejects if a duplicate is found.
   *
   * Only supports 'Simple Key Pair'.
   *
   * @param type - The key pair type to check for.
   * @param newAccountArray - Array of new accounts.
   * @returns The account, if no duplicate is found.
   */
  async checkForDuplicate(
    type: string,
    newAccountArray: string[],
  ): Promise<string[]> {
    const accounts = await this.getAccounts();

    switch (type) {
      case KeyringType.Simple: {
        const isIncluded = Boolean(
          accounts.find(
            (key) =>
              newAccountArray[0] &&
              (key === newAccountArray[0] ||
                key === remove0x(newAccountArray[0])),
          ),
        );

        if (isIncluded) {
          throw new Error(KeyringControllerError.DuplicatedAccount);
        }
        return newAccountArray;
      }

      default: {
        return newAccountArray;
      }
    }
  }

  /**
   * Get Keyring For Account
   *
   * Returns the currently initialized keyring that manages
   * the specified `address` if one exists.
   *
   * @param address - An account address.
   * @returns The keyring of the account, if it exists.
   */
  async getKeyringForAccount(address: string): Promise<Keyring<Json>> {
    // Cast to `Hex` here is safe here because `address` is not nullish.
    // `normalizeToHex` returns `Hex` unless given a nullish value.
    const hexed = normalizeToHex(address) as Hex;

    const candidates = await Promise.all(
      this.keyrings.map(async (keyring) => {
        return Promise.all([keyring, keyring.getAccounts()]);
      }),
    );

    const winners = candidates.filter((candidate) => {
      const accounts = candidate[1].map(normalizeToHex);
      return accounts.includes(hexed);
    });

    if (winners.length && winners[0]?.length) {
      return winners[0][0];
    }

    // Adding more info to the error
    let errorInfo = '';
    if (!isValidHexAddress(hexed)) {
      errorInfo = 'The address passed in is invalid/empty';
    } else if (!candidates.length) {
      errorInfo = 'There are no keyrings';
    } else if (!winners.length) {
      errorInfo = 'There are keyrings, but none match the address';
    }
    throw new Error(
      `${KeyringControllerError.NoKeyring}. Error info: ${errorInfo}`,
    );
  }

  /**
   * Restore Keyring
   *
   * Attempts to initialize a new keyring from the provided serialized payload.
   * On success, updates the memStore keyrings and returns the resulting
   * keyring instance.
   *
   * @param serialized - The serialized keyring.
   * @returns The deserialized keyring.
   */
  async restoreKeyring(
    serialized: SerializedKeyring,
  ): Promise<Keyring<Json> | undefined> {
    const keyring = await this.#restoreKeyring(serialized);
    if (keyring) {
      await this.updateMemStoreKeyrings();
    }
    return keyring;
  }

  /**
   * Get Keyrings by Type
   *
   * Gets all keyrings of the given type.
   *
   * @param type - The keyring types to retrieve.
   * @returns Keyrings matching the specified type.
   */
  getKeyringsByType(type: string): Keyring<Json>[] {
    return this.keyrings.filter((keyring) => keyring.type === type);
  }

  /**
   * Persist All Keyrings
   *
   * Iterates the current `keyrings` array,
   * serializes each one into a serialized array,
   * encrypts that array with the provided `password`,
   * and persists that encrypted string to storage.
   *
   * @returns Resolves to true once keyrings are persisted.
   */
  async persistAllKeyrings(): Promise<boolean> {
    const { encryptionKey, encryptionSalt } = this.memStore.getState();

    if (!this.password && !encryptionKey) {
      throw new Error(KeyringControllerError.MissingCredentials);
    }

    const serializedKeyrings = await Promise.all(
      this.keyrings.map(async (keyring) => {
        const [type, data] = await Promise.all([
          keyring.type,
          keyring.serialize(),
        ]);
        return { type, data };
      }),
    );

    serializedKeyrings.push(...this.unsupportedKeyrings);

    let vault;
    let newEncryptionKey;

    if (this.cacheEncryptionKey) {
      if (this.password) {
        const { vault: newVault, exportedKeyString } =
          await this.encryptor.encryptWithDetail(
            this.password,
            serializedKeyrings,
          );

        vault = newVault;
        newEncryptionKey = exportedKeyString;
      } else if (encryptionKey) {
        const key = await this.encryptor.importKey(encryptionKey);
        const vaultJSON = await this.encryptor.encryptWithKey(
          key,
          serializedKeyrings,
        );
        vaultJSON.salt = encryptionSalt;
        vault = JSON.stringify(vaultJSON);
      }
    } else {
      if (typeof this.password !== 'string') {
        throw new TypeError(KeyringControllerError.WrongPasswordType);
      }
      vault = await this.encryptor.encrypt(this.password, serializedKeyrings);
    }

    if (!vault) {
      throw new Error(KeyringControllerError.MissingVaultData);
    }

    this.store.updateState({ vault });

    // The keyring updates need to be announced before updating the encryptionKey
    // so that the updated keyring gets propagated to the extension first.
    // Not calling {@link updateMemStoreKeyrings} results in the wrong account being selected
    // in the extension.
    await this.updateMemStoreKeyrings();
    if (newEncryptionKey) {
      this.memStore.updateState({
        encryptionKey: newEncryptionKey,
        encryptionSalt: JSON.parse(vault).salt,
      });
    }

    return true;
  }

  /**
   * Unlock Keyrings.
   *
   * Attempts to unlock the persisted encrypted storage,
   * initializing the persisted keyrings to RAM.
   *
   * @param password - The keyring controller password.
   * @param encryptionKey - An exported key string to unlock keyrings with.
   * @param encryptionSalt - The salt used to encrypt the vault.
   * @returns The keyrings array.
   */
  async unlockKeyrings(
    password: string | undefined,
    encryptionKey?: string,
    encryptionSalt?: string,
  ): Promise<Keyring<Json>[]> {
    const encryptedVault = this.store.getState().vault;
    if (!encryptedVault) {
      throw new Error(KeyringControllerError.VaultError);
    }

    await this.#clearKeyrings();

    let vault;

    if (this.cacheEncryptionKey) {
      if (password) {
        const result = await this.encryptor.decryptWithDetail(
          password,
          encryptedVault,
        );
        vault = result.vault;
        this.password = password;

        this.memStore.updateState({
          encryptionKey: result.exportedKeyString,
          encryptionSalt: result.salt,
        });
      } else {
        const parsedEncryptedVault = JSON.parse(encryptedVault);

        if (encryptionSalt !== parsedEncryptedVault.salt) {
          throw new Error(KeyringControllerError.ExpiredCredentials);
        }

        if (typeof encryptionKey !== 'string') {
          throw new TypeError(KeyringControllerError.WrongPasswordType);
        }

        const key = await this.encryptor.importKey(encryptionKey);
        vault = await this.encryptor.decryptWithKey(key, parsedEncryptedVault);

        // This call is required on the first call because encryptionKey
        // is not yet inside the memStore
        this.memStore.updateState({
          encryptionKey,
          // we can safely assume that encryptionSalt is defined here
          // because we compare it with the salt from the vault
          // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
          encryptionSalt: encryptionSalt!,
        });
      }
    } else {
      if (typeof password !== 'string') {
        throw new TypeError(KeyringControllerError.WrongPasswordType);
      }

      vault = await this.encryptor.decrypt(password, encryptedVault);
      this.password = password;
    }

    await Promise.all(vault.map(this.#restoreKeyring.bind(this)));
    await this.updateMemStoreKeyrings();
    return this.keyrings;
  }

  // =======================
  // === Private Methods ===
  // =======================

  /**
   * Create First Key Tree.
   *
   * - Clears the existing vault.
   * - Creates a new vault.
   * - Creates a random new HD Keyring with 1 account.
   * - Makes that account the selected account.
   * - Faucets that account on testnet.
   * - Puts the current seed words into the state tree.
   *
   * @returns A promise that resolves if the operation was successful.
   */
  async #createFirstKeyTree(): Promise<null> {
    await this.#clearKeyrings();

    const keyring = await this.addNewKeyring(KeyringType.HD);
    if (!keyring) {
      throw new Error(KeyringControllerError.NoKeyring);
    }

    const [firstAccount] = await keyring.getAccounts();
    if (!firstAccount) {
      throw new Error(KeyringControllerError.NoAccountOnKeychain);
    }

    const hexAccount = normalizeToHex(firstAccount);
    this.emit('newVault', hexAccount);
    return null;
  }

  /**
   * Restore Keyring Helper
   *
   * Attempts to initialize a new keyring from the provided serialized payload.
   * On success, returns the resulting keyring instance.
   *
   * @param serialized - The serialized keyring.
   * @param serialized.type - Keyring type.
   * @param serialized.data - Keyring data.
   * @returns The deserialized keyring or undefined if the keyring type is unsupported.
   */
  async #restoreKeyring(
    serialized: SerializedKeyring,
  ): Promise<Keyring<Json> | undefined> {
    const { type, data } = serialized;

    let keyring: Keyring<Json> | undefined;
    try {
      keyring = await this.#newKeyring(type, data);
    } catch (error) {
      // Ignore error.
      console.error(error);
    }

    if (!keyring) {
      this.unsupportedKeyrings.push(serialized);
      return undefined;
    }

    // getAccounts also validates the accounts for some keyrings
    await keyring.getAccounts();
    this.keyrings.push(keyring);
    return keyring;
  }

  /**
   * Clear Keyrings
   *
   * Deallocates all currently managed keyrings and accounts.
   * Used before initializing a new vault and after locking
   * MetaMask.
   */
  async #clearKeyrings() {
    // clear keyrings from memory
    for (const keyring of this.keyrings) {
      await this.#destroyKeyring(keyring);
    }
    this.keyrings = [];
    this.memStore.updateState({
      keyrings: [],
    });
  }

  /**
   * Destroy Keyring
   *
   * Some keyrings support a method called `destroy`, that destroys the
   * keyring along with removing all its event listeners and, in some cases,
   * clears the keyring bridge iframe from the DOM.
   *
   * @param keyring - The keyring to destroy.
   */
  async #destroyKeyring(keyring: Keyring<Json>) {
    await keyring.destroy?.();
  }

  /**
   * Unlock Keyrings
   *
   * Unlocks the keyrings.
   *
   * @fires KeyringController#unlock
   */
  #setUnlocked(): void {
    this.memStore.updateState({ isUnlocked: true });
    this.emit('unlock');
  }

  /**
   * Instantiate, initialize and return a new keyring
   *
   * The keyring instantiated is of the given `type`.
   *
   * @param type - The type of keyring to add.
   * @param data - The data to restore a previously serialized keyring.
   * @returns The new keyring.
   */
  async #newKeyring(type: string, data: unknown): Promise<Keyring<Json>> {
    const keyringBuilder = this.getKeyringBuilderForType(type);

    if (!keyringBuilder) {
      throw new Error(
        `${KeyringControllerError.NoKeyringBuilder}. Keyring type: ${type}`,
      );
    }

    const keyring = keyringBuilder();

    // @ts-expect-error Enforce data type after updating clients
    await keyring.deserialize(data);

    if (keyring.init) {
      await keyring.init();
    }

    return keyring;
  }
}

/**
 * Get builder function for `Keyring`
 *
 * Returns a builder function for `Keyring` with a `type` property.
 *
 * @param KeyringConstructor - The Keyring class for the builder.
 * @returns A builder function for the given Keyring.
 */
function keyringBuilderFactory(KeyringConstructor: KeyringClass<Json>) {
  const builder = () => new KeyringConstructor();

  builder.type = KeyringConstructor.type;

  return builder;
}

/**
 * Display For Keyring
 *
 * Is used for adding the current keyrings to the state object.
 *
 * @param keyring - The keyring to display.
 * @returns A keyring display object, with type and accounts properties.
 */
async function displayForKeyring(
  keyring: Keyring<Json>,
): Promise<{ type: string; accounts: string[] }> {
  const accounts = await keyring.getAccounts();

  return {
    type: keyring.type,
    // Cast to `Hex[]` here is safe here because `addresses` has no nullish
    // values, and `normalizeToHex` returns `Hex` unless given a nullish value
    accounts: accounts.map(normalizeToHex) as Hex[],
  };
}

export { KeyringController, keyringBuilderFactory };