fix: check push again when the app comes back to settings (bulwarkmail/webmail#1148)

src/components/settings/NotificationSettings.tsx

@@ -1,6 +1,7 @@
 import React, { useCallback, useEffect, useState } from 'react';
 import {
   ActivityIndicator,
+  AppState,
   Platform,
   StyleSheet,
   Text,
@@ -22,7 +23,8 @@ import {
   DEFAULT_RELAY_BASE_URL,
   disablePushForAccount,
   getStoredRelayBaseUrl,
-  isPushEnabledForAccount,
+  isPushActiveForAccount,
+  shouldRecheckPushState,
   isPushSupported,
   isValidRelayUrl,
   listPushDevices,
@@ -118,11 +120,25 @@ export function NotificationSettings() {
     if (!hydrated) void hydrate();
   }, [hydrated, hydrate]);
 
+  // Read again when the app comes back to the front: notifications may have
+  // been turned off in the phone's settings meanwhile (webmail #1148).
+  const [recheck, setRecheck] = useState(0);
+  const pushStatusKind = React.useRef(pushStatus.kind);
+  pushStatusKind.current = pushStatus.kind;
+  useEffect(() => {
+    const sub = AppState.addEventListener('change', (state) => {
+      if (state === 'active' && shouldRecheckPushState(pushStatusKind.current)) setRecheck((n) => n + 1);
+    });
+    return () => sub.remove();
+  }, []);
+
   useEffect(() => {
     let cancelled = false;
     void (async () => {
       const stored = await getStoredRelayBaseUrl();
-      const enabled = activeAccountId ? await isPushEnabledForAccount(activeAccountId) : false;
+      const enabled = activeAccountId ? await isPushActiveForAccount(activeAccountId) : false;
+      // An enable or disable that started meanwhile has the final word.
+      if (!shouldRecheckPushState(pushStatusKind.current)) return;
       if (cancelled) return;
       if (stored) setRelayUrl(stored);
       setPushEnabled(enabled);
@@ -137,7 +153,7 @@ export function NotificationSettings() {
     })();
     return () => { cancelled = true; };
     // eslint-disable-next-line react-hooks/exhaustive-deps
-  }, [activeAccountId]);
+  }, [activeAccountId, recheck]);
 
   const trimmed = relayUrl.trim().replace(/\/+$/, '');
   const relayValid = isValidRelayUrl(trimmed);

src/lib/__tests__/push-recheck.test.ts

@@ -0,0 +1,38 @@
+import { describe, it, expect, vi, beforeEach } from 'vitest';
+import AsyncStorage from '@react-native-async-storage/async-storage';
+import * as Notifications from 'expo-notifications';
+import { isPushActiveForAccount, shouldRecheckPushState } from '../push-notifications';
+
+// Settings > Notifications read the push state once, when it opened, and
+// read only whether a subscription was stored: notifications turned off in
+// the phone's settings meanwhile still showed as on (webmail #1148).
+
+const ACCOUNT = 'ada@mail.example.com';
+
+beforeEach(async () => {
+  await AsyncStorage.clear();
+  vi.mocked(Notifications.getPermissionsAsync).mockResolvedValue({ granted: true } as never);
+});
+
+describe('push state', () => {
+  it('reads as off once notifications are turned off in the system', async () => {
+    await AsyncStorage.setItem(`push:subscriptionId:v2:${ACCOUNT}`, 'sub-1');
+    await expect(isPushActiveForAccount(ACCOUNT)).resolves.toBe(true);
+    vi.mocked(Notifications.getPermissionsAsync).mockResolvedValue({ granted: false } as never);
+    await expect(isPushActiveForAccount(ACCOUNT)).resolves.toBe(false);
+  });
+
+  it('reads a failed check as off, and an account without push as off', async () => {
+    await expect(isPushActiveForAccount(ACCOUNT)).resolves.toBe(false);
+    await AsyncStorage.setItem(`push:subscriptionId:v2:${ACCOUNT}`, 'sub-1');
+    vi.mocked(Notifications.getPermissionsAsync).mockRejectedValue(new Error('no bridge'));
+    await expect(isPushActiveForAccount(ACCOUNT)).resolves.toBe(false);
+  });
+
+  it('is read again on return unless an enable or disable runs or just failed', () => {
+    expect(shouldRecheckPushState('enabled')).toBe(true);
+    expect(shouldRecheckPushState('idle')).toBe(true);
+    expect(shouldRecheckPushState('busy')).toBe(false);
+    expect(shouldRecheckPushState('error')).toBe(false);
+  });
+});

src/lib/push-notifications.ts

@@ -793,6 +793,31 @@ export async function isPushEnabledForAccount(accountId: string): Promise<boolea
   return (await AsyncStorage.getItem(subscriptionIdKey(accountId))) !== null;
 }
 
+/**
+ * Whether push works for the account right now: it is set up, and the
+ * system still lets the app show notifications (they can be turned off in
+ * the phone's settings while the app is in the background). A failed check
+ * reads as off (webmail #1148).
+ */
+export async function isPushActiveForAccount(accountId: string): Promise<boolean> {
+  try {
+    if (!(await isPushEnabledForAccount(accountId))) return false;
+    const permission = await Notifications.getPermissionsAsync();
+    return permission.granted !== false;
+  } catch {
+    return false;
+  }
+}
+
+/**
+ * Whether Settings > Notifications should read the push state again when
+ * the app comes back: not while an enable or disable runs, nor right after
+ * one failed, which would wipe its message (webmail #1148).
+ */
+export function shouldRecheckPushState(status: 'idle' | 'busy' | 'enabled' | 'error'): boolean {
+  return status !== 'busy' && status !== 'error';
+}
+
 export async function wasPushPromptDismissed(accountId: string): Promise<boolean> {
   return (await AsyncStorage.getItem(promptDismissedKey(accountId))) !== null;
 }