import { Event, isEvent } from "./event";
import { isAbortError } from "../navigation-errors";

export interface SignalEvent<Name extends string | symbol = string>
  extends Event<Name> {
  signal: AbortSignal;
}

export function isAbortSignal(value: unknown): value is AbortSignal {
  function isAbortSignalLike(
    value: unknown
  ): value is Partial<Record<keyof AbortSignal, unknown>> {
    return typeof value === "object";
  }
  return (
    isAbortSignalLike(value) &&
    typeof value.aborted === "boolean" &&
    typeof value.addEventListener === "function"
  );
}

export function isAbortController(value: unknown): value is AbortController {
  function isAbortControllerLike(
    value: unknown
  ): value is Partial<Record<keyof AbortController, unknown>> {
    return typeof value === "object";
  }
  return (
    isAbortControllerLike(value) &&
    typeof value.abort === "function" &&
    isAbortSignal(value.signal)
  );
}

export function isSignalEvent(value: object): value is SignalEvent {
  function isSignalEventLike(value: object): value is { signal?: unknown } {
    return value.hasOwnProperty("signal");
  }
  return (
    isEvent(value) && isSignalEventLike(value) && isAbortSignal(value.signal)
  );
}

export function isSignalHandled(event: Event, error: unknown) {
  if (
    isSignalEvent(event) &&
    event.signal.aborted &&
    error instanceof Error &&
    isAbortError(error)
  ) {
    return true;
  }
}