fix(session): repair the expiry warning and the gaps the review found

Review of 742f376 (Fable). Three defects made the feature not work for the
case it exists for:

- armExpiryWarning() cancelled the alarm before its own early return. Dart
  re-pushes the deadline every 60 s with no dedupe (rule 93's ">5 s" dedupe
  does not exist), so the first sync after the warning came due deleted the
  armed alarm and never re-armed it. Cancel now happens only on the branch
  that re-arms.
- cancelSessionWarningAlarm() built its PendingIntent with
  FLAG_UPDATE_CURRENT, rewriting the live alarm's RUNTIME_TOKEN to "" so a
  delivery in flight was dropped as a stale generation. It now looks the
  existing PendingIntent up with FLAG_NO_CREATE.
- SOCKS5 mode never requested POST_NOTIFICATIONS (requestPermission() is
  TUN-only because it also raises the VPN consent dialog), so on Android 13+
  both alerts were dropped. New plugin method requests it on its own.

Also:
- the native deadline wins the expiry race against the 1 s Dart tick, so the
  commonest session end reached _onVpnConnectionChanged as a bare tunnel
  drop with no message. It now reconciles and sets the expiry text, with
  postAlert false since the native side already posted.
- a resume reconnect no longer resets the support-ad claim: it re-attaches
  to the same server session, where the top-up has already been spent.
- RevoltAlerts sets setOnlyAlertOnce so a replacing post does not re-sound.
- AGENTS.md rule 93 described a setSessionExpiry/SESSION_EXPIRES_AT_MS path
  that no longer exists, dedupe included. Corrected; that stale text is what
  the warning bug was written against.
- CHANGELOG no longer claims the alert covers the tunnel stopping on its own.

flutter analyze clean; debug APK builds.

Co-Authored-By: Claude Opus 5 <[email protected]>

CHANGELOG.md

@@ -11,9 +11,12 @@ Versions follow [semver](https://semver.org/): MAJOR.MINOR.PATCH
 - **Five-minute warning before a session ends.** The VPN service schedules it
   off the same deadline it already enforces, so the warning still arrives when
   the app is closed, and a support top-up moves it with the deadline.
-- **"Disconnected — not protected" notification** whenever a session ends for
+- **"Disconnected — not protected" notification** when a session ends without
-  any reason other than you tapping disconnect: expiry, the data limit, the
+  you asking: the 2-hour expiry, the data limit, the server ending the session,
-  server ending the session, or the tunnel stopping on its own.
+  or the tunnel reporting an error.
+- **SOCKS5 mode now asks for the notification permission.** It never did,
+  because it never raises the VPN consent dialog, so on Android 13+ these
+  alerts would have been dropped before they were shown.
 - **The app now shows what went wrong.** Connect errors, the reason a session
   ended, and progress while connecting appear under the status bar instead of
   the button silently going back to idle.

lib/logic/session_timer.dart

@@ -141,14 +141,28 @@ class SessionTimer extends ChangeNotifier with WidgetsBindingObserver {
     }
 
     if (vpnConnection.status == VpnStatus.disconnected) {
-      // No alert here. The runtime going away covers both the native deadline
+      // The native deadline fires on the exact second while this 1 s tick is
-      // (which posts the alert itself, from a process that outlives this one)
+      // in arbitrary phase, so expiry almost always arrives here rather than
-      // and the notification's Disconnect action, which the user tapped.
+      // at the countdown check in _tick - without this, the commonest session
-      unawaited(_doDisconnect('VPN tunnel dropped'));
+      // end left the UI with nothing to say.
+      _reconcileElapsedTime();
+      final expired = _hasSyncedOnce && _remainingSeconds <= 2;
+      // postAlert is false either way: the native side already posted for its
+      // own deadline, and the notification's Disconnect action is the user
+      // asking, which must never raise a "not protected" alert.
+      unawaited(_doDisconnect(
+        'VPN tunnel dropped',
+        endedMessage:
+            expired ? 'Your session ended. You are not protected.' : null,
+        postAlert: false,
+      ));
     }
   }
 
-  Future<void> start() async {
+  // resetSupportClaim is false when re-attaching to a session the device
+  // already holds: the support top-up is once per server session, and the
+  // claim flag is the only thing enforcing that.
+  Future<void> start({bool resetSupportClaim = true}) async {
     _sessionEpoch++;
     _remainingSeconds = 0;
     _remainingAtLastSync = 0;
@@ -165,10 +179,12 @@ class SessionTimer extends ChangeNotifier with WidgetsBindingObserver {
     _lastEndMessage = null;
     NotificationService.reset();
 
+    if (resetSupportClaim) {
       _supportStateEpoch++;
       _supportRewardClaimed = false;
       _supportRewardStateLoaded = true;
       unawaited(_persistSupportRewardState(false));
+    }
 
     _timer?.cancel();
     _timer = Timer.periodic(const Duration(seconds: 1), _tick);
@@ -233,7 +249,11 @@ class SessionTimer extends ChangeNotifier with WidgetsBindingObserver {
   // not ask for, and its presence is also what posts the "not protected"
   // notification. Both exist so nobody is left on their real IP without being
   // told. A user-requested disconnect passes nothing.
-  Future<void> _doDisconnect(String reason, {String? endedMessage}) async {
+  Future<void> _doDisconnect(
+    String reason, {
+    String? endedMessage,
+    bool postAlert = true,
+  }) async {
     if (_isDisconnecting) return;
     _isDisconnecting = true;
     _sessionEpoch++;
@@ -252,7 +272,7 @@ class SessionTimer extends ChangeNotifier with WidgetsBindingObserver {
     notifyListeners();
 
     await vpnConnection.disconnect();
-    if (endedMessage != null) {
+    if (endedMessage != null && postAlert) {
       unawaited(NotificationService.showDisconnectedAlert());
     }
 

lib/logic/vpn_connection.dart

@@ -224,6 +224,18 @@ class VpnConnection extends ChangeNotifier {
       return false;
     }
 
+    // SOCKS5 mode skips requestPermission below (it would raise the VPN
+    // consent dialog for an interface it never creates), so ask for the
+    // notification permission on its own - the session alerts need it.
+    if (!kIsWeb && _activeMode == ConnectionMode.proxy) {
+      try {
+        await _nativeControl.invokeMethod<void>('requestNotificationPermission');
+      } catch (e) {
+        debugPrint('[VPN] Notification permission request failed: $e');
+      }
+      if (!_isCurrentConnect(connectEpoch)) return false;
+    }
+
     if (!kIsWeb && _activeMode == ConnectionMode.tun) {
       final ok = await _vless.requestPermission();
       if (!_isCurrentConnect(connectEpoch)) return false;

lib/screens/settings/in_settings/connection_mode.dart

@@ -82,7 +82,7 @@ class _ConnectionModeTileState extends State<ConnectionModeTile> {
       if (!mounted) return;
       if (await vpn.connect(resume: true)) {
         if (!mounted) return;
-        await timer.start();
+        await timer.start(resetSupportClaim: false);
       }
     } finally {
       if (mounted) {

local_packages/flutter_vless_android-1.1.5/android/src/main/kotlin/com/github/tfox/flutter_vless/FlutterVlessPlugin.kt

@@ -240,6 +240,31 @@ class FlutterVlessPlugin : FlutterPlugin, ActivityAware, PluginRegistry.Activity
                 }
             }
 
+            // POST_NOTIFICATIONS on its own, without VpnService.prepare: SOCKS5
+            // mode never establishes a VPN interface, so it never called
+            // requestPermission and both session alerts were dropped unasked
+            // for on Android 13+.
+            "requestNotificationPermission" -> {
+                val currentActivity = activity
+                if (currentActivity == null) {
+                    result.error("NO_ACTIVITY", "Activity is not attached", null)
+                    return
+                }
+                if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.TIRAMISU &&
+                    ActivityCompat.checkSelfPermission(
+                        currentActivity,
+                        Manifest.permission.POST_NOTIFICATIONS,
+                    ) != PackageManager.PERMISSION_GRANTED
+                ) {
+                    ActivityCompat.requestPermissions(
+                        currentActivity,
+                        arrayOf(Manifest.permission.POST_NOTIFICATIONS),
+                        REQUEST_CODE_POST_NOTIFICATIONS,
+                    )
+                }
+                result.success(null)
+            }
+
             "requestPermission" -> {
                 val currentActivity = activity
                 if (currentActivity == null) {

local_packages/flutter_vless_android-1.1.5/android/src/main/kotlin/com/github/tfox/flutter_vless/xray/service/XrayVPNService.kt

@@ -473,15 +473,18 @@ class XrayVPNService : VpnService() {
     // scheduled must never stop a working tunnel, so nothing here fails closed.
     // Dart re-pushes the deadline on every sync, so this runs about once a minute.
     private fun armExpiryWarning(runtimeToken: String, expiresAtEpochMs: Long) {
-        cancelSessionWarningAlarm()
         if (runtimeToken.isEmpty()) return
 
         val warnAt = expiresAtEpochMs - RevoltAlerts.WARNING_LEAD_MS
         // Deadline already inside the warning window (or past): either the alarm
         // has fired and its notification should stay up, or this is the short
-        // bootstrap deadline at connect, which must not warn at all.
+        // bootstrap deadline at connect, which must not warn at all. Nothing is
+        // cancelled here - Dart re-pushes the same deadline every 60 s with no
+        // dedupe, so cancelling on this branch would reliably delete the armed
+        // warning on the first sync after it came due and never re-arm it.
         if (warnAt <= System.currentTimeMillis()) return
 
+        cancelSessionWarningAlarm()
         // More than the lead away, so any warning on screen belongs to an older
         // deadline - a support top-up just pushed it out.
         RevoltAlerts.cancelExpiryWarning(this)
@@ -691,12 +694,24 @@ class XrayVPNService : VpnService() {
     private fun cancelSessionWarningAlarm() {
         try {
             val alarmManager = getSystemService(Context.ALARM_SERVICE) as AlarmManager
-            alarmManager.cancel(sessionWarningPendingIntent(""))
+            // Look the existing PendingIntent up instead of building one: with
+            // FLAG_UPDATE_CURRENT, constructing it to cancel rewrites the live
+            // alarm's RUNTIME_TOKEN to "" first, and a delivery already in
+            // flight would then be dropped as a stale generation.
+            existingSessionWarningPendingIntent()?.let { alarmManager.cancel(it) }
         } catch (e: Exception) {
             Log.w(TAG, "Failed to cancel session-warning alarm", e)
         }
     }
 
+    private fun existingSessionWarningPendingIntent(): PendingIntent? {
+        val intent = Intent(this, XrayVPNService::class.java)
+            .putExtra(EXTRA_SESSION_WARNING, true)
+        val flags = PendingIntent.FLAG_NO_CREATE or
+            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) PendingIntent.FLAG_IMMUTABLE else 0
+        return PendingIntent.getService(this, SESSION_WARNING_REQUEST_CODE, intent, flags)
+    }
+
     // A PendingIntent is identified by component plus request code, not extras,
     // so the warning needs its own code or it would overwrite - and later
     // cancel - the expiry alarm.

local_packages/flutter_vless_android-1.1.5/android/src/main/kotlin/com/github/tfox/flutter_vless/xray/utils/RevoltAlerts.kt

@@ -97,6 +97,9 @@ object RevoltAlerts {
                 .setSmallIcon(icon)
                 .setAutoCancel(true)
                 .setOngoing(false)
+                // Both processes can post the disconnected alert; the second
+                // post replaces the first and must not sound again.
+                .setOnlyAlertOnce(true)
 
             launchIntent(context)?.let { builder.setContentIntent(it) }