import { Event, isEvent } from "./event";

export interface RespondEvent<
  Name extends string | symbol = string,
  T = unknown
> extends Event<Name> {
  /**
   * @param value
   * @throws InvalidStateError
   */
  respondWith(value: T | Promise<T>): void;
}

export function isRespondEvent<T = unknown>(
  value: object
): value is RespondEvent<string, T> {
  function isRespondEventLike(
    value: object
  ): value is Partial<Record<keyof RespondEvent, unknown>> {
    return isEvent(value);
  }
  return isRespondEventLike(value) && typeof value.respondWith === "function";
}