export type AppShutdownState = "running" | "stopping" | "stopped";

export type ShutdownService = {
  getState: () => AppShutdownState;
  stop: () => Promise<void>;
};

export function createShutdownService(stopRuntime: () => Promise<void>): ShutdownService {
  let state: AppShutdownState = "running";
  let stopPromise: Promise<void> | null = null;

  return {
    getState: () => state,
    stop: () => {
      if (state === "stopped") {
        return Promise.resolve();
      }

      if (stopPromise) {
        return stopPromise;
      }

      state = "stopping";
      stopPromise = stopRuntime().finally(() => {
        state = "stopped";
        stopPromise = null;
      });

      return stopPromise;
    },
  };
}