Appwrite auth state changes via stream

import type { Models, RealtimeResponseEvent } from 'appwrite'

import { useAppwrite } from './useAppwrite'

type User = Models.User<Models.Preferences>
type UseAppwriteAuthStateChangedOptions = {
  onAuthenticated: (payload: User) => void
  onUnauthenticated: (payload: User) => void
  onSubscribed?: () => void
  onUnsubscribed?: () => void
}

const ACCOUNT_CHANNEL = 'account'

function isCreateSession(events: string[], _payload: unknown): _payload is User {
  return events.includes('users.*.sessions.*.create')
}

function isDeleteSession(events: string[], _payload: unknown): _payload is User {
  return events.includes('users.*.sessions.*.delete')
}

export function useAppwriteAuthStateChanged({
  onAuthenticated,
  onSubscribed,
  onUnauthenticated,
  onUnsubscribed,
}: UseAppwriteAuthStateChangedOptions) {
  const appwrite = useAppwrite()
  const unsubscribeCb = ref<() => void>(() => undefined)

  function handleUpdate({ events, payload }: RealtimeResponseEvent<unknown>) {
    if (isCreateSession(events, payload)) {
      onAuthenticated(payload)
      resubscribe()
    } else if (isDeleteSession(events, payload)) {
      onUnauthenticated(payload)
      resubscribe()
    }
  }

  function subscribe() {
    unsubscribeCb.value = appwrite.client.subscribe(ACCOUNT_CHANNEL, handleUpdate)
    onSubscribed?.()
  }

  function resubscribe() {
    unsubscribe()
    subscribe()
  }

  function unsubscribe() {
    unsubscribeCb.value()
    onUnsubscribed?.()
  }

  onMounted(() => subscribe())
  onUnmounted(() => unsubscribe())

  return {
    unsubscribe,
  }
}