import { platform } from '~/platform';
import { AuthEvent, HoppUser } from '~/platform/auth';
import { Subscription } from 'rxjs';
import { onBeforeUnmount, onMounted, watch, WatchStopHandle } from 'vue';
import { useReadonlyStream } from './stream';

/**
 * A Vue composable function that is called when the auth status
 * is being updated to being logged in (fired multiple times),
 * this is also called on component mount if the login
 * was already resolved before mount.
 */
export function onLoggedIn(exec: (user: HoppUser) => void) {
  const currentUser = useReadonlyStream(
    platform.auth.getCurrentUserStream(),
    platform.auth.getCurrentUser()
  );

  let watchStop: WatchStopHandle | null = null;

  onMounted(() => {
    if (currentUser.value) exec(currentUser.value);

    watchStop = watch(currentUser, (newVal, prev) => {
      if (prev === null && newVal !== null) {
        exec(newVal);
      }
    });
  });

  onBeforeUnmount(() => {
    watchStop?.();
  });
}

/**
 * A Vue composable function that calls its param function
 * when a new event (login, logout etc.) happens in
 * the auth system.
 *
 * NOTE: Unlike `onLoggedIn` for which the callback will be called once on mount with the current state,
 * here the callback will only be called on authentication event occurances.
 * You might want to check the auth state from an `onMounted` hook or something
 * if you want to access the initial state
 *
 * @param func A function which accepts an event
 */
export function onAuthEvent(func: (ev: AuthEvent) => void) {
  const authEvents$ = platform.auth.getAuthEventsStream();

  let sub: Subscription | null = null;

  onMounted(() => {
    sub = authEvents$.subscribe((ev) => {
      func(ev);
    });
  });

  onBeforeUnmount(() => {
    sub?.unsubscribe();
  });
}