type CasperWalletProviderOptions = {
  timeout: number; // timeout of request to extension (in ms)
};

type CasperWalletProvider = (
  options?: CasperWalletProviderOptions
) => {
  /**
   * Get the connection status of the Casper Wallet extension
   * @returns `true` value when currently connected at least one account, `false` otherwise.
   */
  isConnected: () => Promise<boolean>;

  /**
   * Request the connect interface with the Casper Wallet extension.
   * Will not show UI for already connected accounts and return true immediately
   *
   * emits event of type `Connected` when successfully connected.
   * @returns `true` value when connection request is accepted by the user or when account is already connected, `false` otherwise.
   */
  requestConnection: () => Promise<boolean>;

  /**
   * Request the switch account interface with the Casper Wallet extension
   *
   * emits event of type `ActiveKeyChanged` when successfully switched account.
   * @returns `true` value when successfully switched account, `false` otherwise.
   */
  requestSwitchAccount(): Promise<boolean>;

  /**
   * Request the sign deploy interface with the Casper Wallet extension
   * @param deployJson stringified json of a deploy can be generated by `DeployUtil.deployToJson`
   * @param signingPublicKeyHex public key (in hex format)
   * @returns a payload response when user responded to transaction request, it will contain signature if approved, or cancelled === true flag when rejected.
   */
  sign(
    deployJson: string,
    signingPublicKeyHex: string
  ): Promise<SignatureResponse>;

  /**
   * Request the sign message interface with the Casper Wallet extension
   * @param message message to sign as string
   * @param signingPublicKeyHex public key (in hex format)
   * @returns a payload response when user responded to transaction request, it will contain signature if approved, or cancelled === true flag when rejected.
   */
  signMessage(
    message: string,
    signingPublicKeyHex: string
  ): Promise<SignatureResponse>;

  /**
   * Disconnect the Casper Wallet extension
   *
   * emits event of type `Disconnected` when successfully disconnected.
   * @returns `true` when successfully disconnected, `false` otherwise.
   */
  disconnectFromSite(): Promise<boolean>;

  /**
   * Get the active public key of the Casper Wallet extension
   * @returns hex of the active public key.
   * @throws when wallet is locked (err.code: 1)
   * @throws when active account not approved to connect with the site (err.code: 2)
   */
  getActivePublicKey(): Promise<string>;

  /**
   * Get version of the Casper Wallet extension
   * @returns version of the installed wallet extension.
   */
  getVersion(): Promise<string>;
};

type SignatureResponse =
  | {
      cancelled: true; // if sign was cancelled
    }
  | {
      cancelled: false; // if sign was successfull
      signatureHex: string; // signature as hex hash
      signature: Uint8Array; // signature as byte array
    };

type CasperWalletState = {
  /** contain wallet is locked flag */
  isLocked: boolean;
  /** if unlocked contain connected status flag of active key otherwise null */
  isConnected: boolean | null;
  /** if unlocked and connected contain active key otherwise null */
  activeKey: string | null;
};

const EVENT_TYPE_PREFIX = 'casper-wallet';

/**
 * Event types emitted by the Casper Wallet extension.
 */
const CasperWalletEventTypes = {
  /** Account was connected using the wallet: */
  Connected: `${EVENT_TYPE_PREFIX}:connected`,
  /** Active key was changed using the Wallet interface: */
  ActiveKeyChanged: `${EVENT_TYPE_PREFIX}:activeKeyChanged`,
  /** Account was disconnected using the wallet: */
  Disconnected: `${EVENT_TYPE_PREFIX}:disconnected`,
  /** Browser tab was changed to some connected site: */
  TabChanged: `${EVENT_TYPE_PREFIX}:tabChanged`,
  /** Wallet was locked: */
  Locked: `${EVENT_TYPE_PREFIX}:locked`,
  /** Wallet was unlocked: */
  Unlocked: `${EVENT_TYPE_PREFIX}:unlocked`
} as const;

interface Window {
  CasperWalletProvider?: CasperWalletProvider;
  CasperWalletEventTypes?: typeof CasperWalletEventTypes;
}