bsky-social-app/src/lib/notifications/notifications.ts

import {useCallback, useEffect} from 'react'
import {Platform} from 'react-native'
import * as Notifications from 'expo-notifications'
import {getBadgeCountAsync, setBadgeCountAsync} from 'expo-notifications'
import {type Client} from '@atproto/lex'
import debounce from 'lodash.debounce'

import {
  NOTIF_SERVICE,
  PUBLIC_APPVIEW_DID,
  PUBLIC_STAGING_APPVIEW_DID,
} from '#/lib/constants'
import {logger as notyLogger} from '#/lib/notifications/util'
import {isNetworkError} from '#/lib/strings/errors'
import {type SessionAccount, usePdsClient, useSession} from '#/state/session'
import BackgroundNotificationHandler from '#/../modules/expo-background-notification-handler'
import {useAgeAssurance} from '#/ageAssurance'
import {useAnalytics} from '#/analytics'
import {IS_DEV, IS_NATIVE} from '#/env'
import {app} from '#/lexicons'

/**
 * A resumed single-use account client paired with the account's service origin
 * and handle. Produced by `createTemporaryClientsAndResume` (session util) and
 * consumed by {@link unregisterPushToken}, which needs the service host to pick
 * the appview DID and the handle for a debug log line without reaching into the
 * session internals.
 */
export type TemporaryPushClient = {
  client: Client
  service: string
  handle: string
}

/**
 * @private
 * Registers the device's push notification token with the Bluesky server.
 */
async function _registerPushToken({
  client,
  currentAccount,
  token,
  extra = {},
}: {
  client: Client
  currentAccount: SessionAccount
  token: Notifications.DevicePushToken
  extra?: {
    ageRestricted?: boolean
  }
}) {
  try {
    const payload: app.bsky.notification.registerPush.$InputBody = {
      serviceDid: currentAccount.service?.includes('staging')
        ? PUBLIC_STAGING_APPVIEW_DID
        : PUBLIC_APPVIEW_DID,
      platform: Platform.OS,
      token: token.data,
      appId: 'xyz.blueskyweb.app',
      ageRestricted: extra.ageRestricted ?? false,
    }

    notyLogger.debug(`registerPushToken: registering`, {...payload})

    await client.call(app.bsky.notification.registerPush, payload, {
      service: NOTIF_SERVICE,
    })

    notyLogger.debug(`registerPushToken: success`)
  } catch (error) {
    if (!isNetworkError(error)) {
      notyLogger.warn(`registerPushToken: failed`, {safeMessage: error})
    }
  }
}

/**
 * @private
 * Debounced version of `_registerPushToken` to prevent multiple calls.
 */
const _registerPushTokenDebounced = debounce(_registerPushToken, 100)

/**
 * Hook to register the device's push notification token with the Bluesky. If
 * the user is not logged in, this will do nothing.
 *
 * Use this instead of using `_registerPushToken` or
 * `_registerPushTokenDebounced` directly.
 */
export function useRegisterPushToken() {
  const client = usePdsClient()
  const {currentAccount} = useSession()

  return useCallback(
    ({
      token,
      isAgeRestricted,
    }: {
      token: Notifications.DevicePushToken
      isAgeRestricted: boolean
    }) => {
      if (!currentAccount) return
      return _registerPushTokenDebounced({
        client,
        currentAccount,
        token,
        extra: {
          ageRestricted: isAgeRestricted,
        },
      })
    },
    [client, currentAccount],
  )
}

/**
 * Retreive the device's push notification token, if permissions are granted.
 */
async function getPushToken() {
  const granted = (await Notifications.getPermissionsAsync()).granted
  notyLogger.debug(`getPushToken`, {granted})
  if (granted) {
    return Notifications.getDevicePushTokenAsync()
  }
}

/**
 * Hook to get the device push token and register it with the Bluesky server.
 * Should only be called after a user has logged-in, since registration is an
 * authed endpoint.
 *
 * N.B. A previous regression in `expo-notifications` caused
 * `addPushTokenListener` to not fire on Android after calling
 * `getPushToken()`. Therefore, as insurance, we also call
 * `registerPushToken` here.
 *
 * Because `registerPushToken` is debounced, even if the the listener _does_
 * fire, it's OK to also call `registerPushToken` below since only a single
 * call will be made to the server (ideally). This does race the listener (if
 * it fires), so there's a possibility that multiple calls will be made, but
 * that is acceptable.
 *
 * @see https://github.com/expo/expo/issues/28656
 * @see https://github.com/expo/expo/issues/29909
 * @see https://github.com/bluesky-social/social-app/pull/4467
 */
export function useGetAndRegisterPushToken() {
  const aa = useAgeAssurance()
  const registerPushToken = useRegisterPushToken()
  return useCallback(
    async ({
      isAgeRestricted: isAgeRestrictedOverride,
    }: {
      isAgeRestricted?: boolean
    } = {}) => {
      if (!IS_NATIVE || IS_DEV) return

      /**
       * This will also fire the listener added via `addPushTokenListener`. That
       * listener also handles registration.
       */
      const token = await getPushToken()

      notyLogger.debug(`useGetAndRegisterPushToken`, {
        token: token ?? 'undefined',
      })

      if (token) {
        /**
         * The listener should have registered the token already, but just in
         * case, call the debounced function again.
         */
        registerPushToken({
          token,
          isAgeRestricted:
            isAgeRestrictedOverride ?? aa.state.access !== aa.Access.Full,
        })
      }

      return token
    },
    [registerPushToken, aa],
  )
}

/**
 * Hook to register the device's push notification token with the Bluesky
 * server, as well as listen for push token updates, should they occurr.
 *
 * Registered via the shell, which wraps the navigation stack, meaning if we
 * have a current account, this handling will be registered and ready to go.
 */
export function useNotificationsRegistration() {
  const {currentAccount} = useSession()
  const registerPushToken = useRegisterPushToken()
  const getAndRegisterPushToken = useGetAndRegisterPushToken()
  const aa = useAgeAssurance()

  useEffect(() => {
    /**
     * We want this to init right away _after_ we have a logged in user, and
     * _after_ we've loaded their age assurance state.
     */
    if (!currentAccount) return

    notyLogger.debug(`useNotificationsRegistration`)

    /**
     * Init push token, if permissions are granted already. If they weren't,
     * they'll be requested by the `useRequestNotificationsPermission` hook
     * below.
     */
    getAndRegisterPushToken()

    /**
     * Register the push token with the Bluesky server, whenever it changes.
     * This is also fired any time `getDevicePushTokenAsync` is called.
     *
     * Since this is registered immediately after `getAndRegisterPushToken`, it
     * should also detect that getter and be fired almost immediately after this.
     *
     * According to the Expo docs, there is a chance that the token will change
     * while the app is open in some rare cases. This will fire
     * `registerPushToken` whenever that happens.
     *
     * @see https://docs.expo.dev/versions/latest/sdk/notifications/#addpushtokenlistenerlistener
     */
    const subscription = Notifications.addPushTokenListener(async token => {
      registerPushToken({
        token,
        isAgeRestricted: aa.state.access !== aa.Access.Full,
      })
      notyLogger.debug(`addPushTokenListener callback`, {token})
    })

    return () => {
      subscription.remove()
    }
  }, [currentAccount, getAndRegisterPushToken, registerPushToken, aa])
}

/**
 * Tracks whether we have already shown the OS notification permission prompt
 * during this app session. On Android `canAskAgain` stays true after a single
 * in-app denial, so without this guard a later call site (e.g. Home after
 * Login) would surface a second prompt. Resets on app restart.
 */
let hasRequestedPermissionsThisSession = false

export function useRequestNotificationsPermission() {
  const ax = useAnalytics()
  const {currentAccount} = useSession()
  const getAndRegisterPushToken = useGetAndRegisterPushToken()

  return async (
    context: 'StartOnboarding' | 'AfterOnboarding' | 'Login' | 'Home',
  ) => {
    const permissions = await Notifications.getPermissionsAsync()

    if (
      !IS_NATIVE ||
      permissions?.status === 'granted' ||
      (permissions?.status === 'denied' && !permissions.canAskAgain)
    ) {
      return
    }
    if (context === 'AfterOnboarding') {
      return
    }
    if (context === 'Home' && !currentAccount) {
      return
    }

    if (hasRequestedPermissionsThisSession) {
      return
    }
    hasRequestedPermissionsThisSession = true

    const res = await Notifications.requestPermissionsAsync({
      ios: {
        /*
         * These three default to true when no argument is passed to
         * `requestPermissionsAsync`, but passing an options object opts out of
         * that default, so we have to set them explicitly to preserve the
         * existing behavior.
         */
        allowAlert: true,
        allowBadge: true,
        allowSound: true,
        /*
         * Adds an in-app notification settings button to the system Settings
         * screen for Bluesky. When tapped, iOS calls back into the app, which
         * we route to the in-app notification settings (see the
         * NotificationSettings module in expo-bluesky-swiss-army).
         */
        provideAppNotificationSettings: true,
      },
    })

    ax.metric(`notifications:request`, {
      context: context,
      status: res.status,
    })

    if (res.granted) {
      if (currentAccount) {
        /**
         * If we have an account in scope, we can safely call
         * `getAndRegisterPushToken`.
         */
        getAndRegisterPushToken()
      } else {
        /**
         * Right after login, `currentAccount` in this scope will be undefined,
         * but calling `getPushToken` will result in `addPushTokenListener`
         * listeners being called, which will handle the registration with the
         * Bluesky server.
         */
        getPushToken()
      }
    }
  }
}

export async function decrementBadgeCount(by: number) {
  if (!IS_NATIVE) return

  let count = await getBadgeCountAsync()
  count -= by
  if (count < 0) {
    count = 0
  }

  await BackgroundNotificationHandler.setBadgeCountAsync(count)
  await setBadgeCountAsync(count)
}

export async function resetBadgeCount() {
  await BackgroundNotificationHandler.setBadgeCountAsync(0)
  await setBadgeCountAsync(0)
}

export async function unregisterPushToken(clients: TemporaryPushClient[]) {
  if (!IS_NATIVE) return

  try {
    const token = await getPushToken()
    if (token) {
      for (const {client, service, handle} of clients) {
        await client.call(
          app.bsky.notification.unregisterPush,
          {
            serviceDid: service.includes('staging')
              ? PUBLIC_STAGING_APPVIEW_DID
              : PUBLIC_APPVIEW_DID,
            platform: Platform.OS,
            token: token.data,
            appId: 'xyz.blueskyweb.app',
          },
          {
            service: NOTIF_SERVICE,
          },
        )
        notyLogger.debug(`Push token unregistered for ${handle}`)
      }
    } else {
      notyLogger.debug('Tried to unregister push token, but could not find one')
    }
  } catch (error) {
    notyLogger.debug('Failed to unregister push token', {message: error})
  }
}