export interface ClosableRuntime {
  close(): Promise<void>;
}
export interface SignalTarget {
  once(event: 'SIGINT' | 'SIGTERM', listener: () => void): unknown;
  removeListener(event: 'SIGINT' | 'SIGTERM', listener: () => void): unknown;
}
export function installBoundedShutdown(
  target: SignalTarget,
  runtime: ClosableRuntime,
  options: { readonly timeoutMs?: number; readonly terminate?: () => void } = {},
): () => Promise<void> {
  let shutdown: Promise<void> | undefined;
  const timeoutMs = options.timeoutMs ?? 5_000;
  const stop = (): Promise<void> => {
    if (shutdown) return shutdown;
    let timeout: ReturnType<typeof setTimeout> | undefined;
    const deadline = new Promise<void>((resolve) => {
      timeout = setTimeout(() => {
        options.terminate?.();
        resolve();
      }, timeoutMs);
    });
    shutdown = Promise.race([runtime.close(), deadline]).finally(() => {
      if (timeout !== undefined) clearTimeout(timeout);
      target.removeListener('SIGINT', listener);
      target.removeListener('SIGTERM', listener);
    });
    return shutdown;
  };
  const listener = (): void => {
    void stop();
  };
  target.once('SIGINT', listener);
  target.once('SIGTERM', listener);
  return stop;
}