refact: restart remote device, autoconnect (#15290)

* refact: restart remote device, autoconnect

Signed-off-by: fufesou <linlong1266@gmail.com>

* fix: guard restart reconnect timer after session close

Signed-off-by: fufesou <linlong1266@gmail.com>

* Simple refactor

Signed-off-by: fufesou <linlong1266@gmail.com>

* fix(restart): auto connect, comments

Signed-off-by: fufesou <linlong1266@gmail.com>

---------

Signed-off-by: fufesou <linlong1266@gmail.com>

flutter/lib/models/model.dart

@@ -55,6 +55,8 @@ import 'package:flutter_hbb/native/custom_cursor.dart'
 typedef HandleMsgBox = Function(Map<String, dynamic> evt, String id);
 typedef ReconnectHandle = Function(OverlayDialogManager, SessionID, bool);
 final _constSessionId = Uuid().v4obj();
+// Empirical restart reconnect cadence: keep the last frame briefly and retry quickly.
+const _restartReconnectSilentDelaySecs = 5;
 
 class CachedPeerData {
   Map<String, dynamic> updatePrivacyMode = {};
@@ -119,6 +121,7 @@ class FfiModel with ChangeNotifier {
   bool _touchMode = false;
   late VirtualMouseMode virtualMouseMode;
   Timer? _timer;
+  Timer? _restartReconnectDelayTimer;
   var _reconnects = 1;
   DateTime? _offlineReconnectStartTime;
   bool _viewOnly = false;
@@ -250,6 +253,7 @@ class FfiModel with ChangeNotifier {
     _inputBlocked = false;
     _timer?.cancel();
     _timer = null;
+    resetRestartReconnectState();
     clearPermissions();
     waitForImageTimer?.cancel();
     timerScreenshot?.cancel();
@@ -341,6 +345,7 @@ class FfiModel with ChangeNotifier {
       } else if (name == 'connection_ready') {
         setConnectionType(peerId, evt['secure'] == 'true',
             evt['direct'] == 'true', evt['stream_type'] ?? '');
+        resetRestartReconnectState();
       } else if (name == 'switch_display') {
         // switch display is kept for backward compatibility
         handleSwitchDisplay(evt, sessionId, peerId);
@@ -922,8 +927,28 @@ class FfiModel with ChangeNotifier {
       enterUserLoginAndPasswordDialog(
           sessionId, dialogManager, 'terminal-admin-login-tip', false);
     } else if (type == 'restarting') {
-      showMsgBox(sessionId, type, title, text, link, false, dialogManager,
+      // Treat restart messages as reconnect control events. Rust still sends
-          hasCancel: false);
+      // title/text for legacy UI and translation reuse; Flutter keeps the last
+      // frame briefly, then shows the Connecting overlay.
+      if (_restartReconnectDelayTimer == null) {
+        parent.target?.inputModel.setRelativeMouseMode(false);
+        bind.sessionReconnect(sessionId: sessionId, forceRelay: false);
+        clearPermissions();
+        // Retry once more after the silent window so restart reconnect attempts
+        // are spaced by the empirical short cadence instead of only updating UI.
+        _restartReconnectDelayTimer =
+            Timer(Duration(seconds: _restartReconnectSilentDelaySecs), () {
+          _restartReconnectDelayTimer = null;
+          if (parent.target?.closed == true) {
+            return;
+          }
+          reconnect(dialogManager, sessionId, false);
+        });
+      }
+    } else if (type == 'restarting-show') {
+      _restartReconnectDelayTimer?.cancel();
+      _restartReconnectDelayTimer = null;
+      reconnect(dialogManager, sessionId, false);
     } else if (type == 'wait-remote-accept-nook') {
       showWaitAcceptDialog(sessionId, type, title, text, dialogManager);
     } else if (type == 'on-uac' || type == 'on-foreground-elevated') {
@@ -949,6 +974,11 @@ class FfiModel with ChangeNotifier {
     }
   }
 
+  void resetRestartReconnectState() {
+    _restartReconnectDelayTimer?.cancel();
+    _restartReconnectDelayTimer = null;
+  }
+
   /// Auto-retry check for "Remote desktop is offline" error.
   /// returns true to auto-retry, false otherwise.
   bool shouldAutoRetryOnOffline(
@@ -1374,6 +1404,7 @@ class FfiModel with ChangeNotifier {
       if (displays.isNotEmpty) {
         _reconnects = 1;
         _offlineReconnectStartTime = null;
+        resetRestartReconnectState();
         waitForFirstImage.value = true;
         isRefreshing = false;
       }
@@ -3666,6 +3697,7 @@ class FFI {
 
   /// Mobile reuse FFI
   void mobileReset() {
+    ffiModel.resetRestartReconnectState();
     ffiModel.waitForFirstImage.value = true;
     ffiModel.isRefreshing = false;
     ffiModel.waitForImageDialogShow.value = true;
@@ -3879,6 +3911,7 @@ class FFI {
     }
     if (ffiModel.waitForFirstImage.value == true) {
       ffiModel.waitForFirstImage.value = false;
+      ffiModel.resetRestartReconnectState();
       dialogManager.dismissAll();
       await canvasModel.updateViewStyle();
       await canvasModel.updateScrollStyle();

src/client.rs

@@ -96,6 +96,8 @@ pub mod screenshot;
 
 pub const MILLI1: Duration = Duration::from_millis(1);
 pub const SEC30: Duration = Duration::from_secs(30);
+// Empirical restart reconnect grace window.
+const RESTART_REMOTE_DEVICE_GRACE: Duration = Duration::from_secs(5 * 60);
 pub const VIDEO_QUEUE_SIZE: usize = 120;
 const MAX_DECODE_FAIL_COUNTER: usize = 3;
 
@@ -1740,7 +1742,10 @@ pub struct LoginConfigHandler {
     features: Option<Features>,
     pub session_id: u64, // used for local <-> server communication
     pub supported_encoding: SupportedEncoding,
-    pub restarting_remote_device: bool,
+    restarting_remote_device: bool,
+    // Start time of the restart grace window. On Windows the peer may briefly
+    // reconnect before the real reboot disconnect.
+    restart_remote_device_at: Option<Instant>,
     pub force_relay: bool,
     pub direct: Option<bool>,
     pub received: bool,
@@ -1849,7 +1854,7 @@ impl LoginConfigHandler {
         }
         self.session_id = sid;
         self.supported_encoding = Default::default();
-        self.restarting_remote_device = false;
+        self.clear_restarting_remote_device();
         self.force_relay =
             config::option2bool("force-always-relay", &self.get_option("force-always-relay"))
                 || force_relay
@@ -2779,6 +2784,30 @@ impl LoginConfigHandler {
         msg_out
     }
 
+    pub fn mark_restarting_remote_device(&mut self) {
+        self.restarting_remote_device = true;
+        self.restart_remote_device_at = Some(Instant::now());
+    }
+
+    pub fn clear_restarting_remote_device(&mut self) {
+        self.restarting_remote_device = false;
+        self.restart_remote_device_at = None;
+    }
+
+    pub fn is_restarting_remote_device(&self) -> bool {
+        if !self.restarting_remote_device {
+            return false;
+        }
+        // Keep this flag alive for a short grace window instead of clearing it on
+        // connection_ready or the first peer bytes. During OS restart the peer can
+        // briefly reconnect before the real reboot disconnect, and clearing it too
+        // early would let the next disconnect escape the restart flow and fall back
+        // to the normal error dialog / manual reconnect path.
+        self.restart_remote_device_at
+            .map(|started_at| started_at.elapsed() < RESTART_REMOTE_DEVICE_GRACE)
+            .unwrap_or(false)
+    }
+
     pub fn get_conn_token(&self) -> Option<String> {
         if self.password.is_empty() {
             return None;
@@ -3718,9 +3747,18 @@ pub trait Interface: Send + Clone + 'static + Sized {
     fn on_establish_connection_error(&self, err: String) {
         let title = "Connection Error";
         let text = err.to_string();
-        let lc = self.get_lch();
+        let lch = self.get_lch();
-        let direct = lc.read().unwrap().direct;
+        let (is_restarting, direct, received) = {
-        let received = lc.read().unwrap().received;
+            let lc = lch.read().unwrap();
+            (lc.is_restarting_remote_device(), lc.direct, lc.received)
+        };
+        if is_restarting {
+            log::info!("Restart remote device, suppress connection error: {err}");
+            // Flutter treats this as a reconnect control event. The text is kept
+            // for legacy UI and existing translation reuse.
+            self.msgbox("restarting", "Restarting remote device", "Connection in progress. Please wait.", "");
+            return;
+        }
 
         let mut relay_hint = false;
         let mut relay_hint_type = "relay-hint";

src/client/io_loop.rs

@@ -10,6 +10,10 @@ use crate::{
     common::get_default_sound_input,
     ui_session_interface::{InvokeUiSession, Session},
 };
+
+// Empirical no-data window before exposing the restart reconnect state to the UI.
+// Restart msgbox text is kept as a legacy UI fallback; Flutter handles the type as a control event.
+const RESTART_REMOTE_DEVICE_NO_DATA_TIMEOUT: Duration = Duration::from_secs(5);
 #[cfg(feature = "unix-file-copy-paste")]
 use crate::{clipboard::try_empty_clipboard_files, clipboard_file::unix_file_clip};
 #[cfg(any(
@@ -153,7 +157,6 @@ impl<T: InvokeUiSession> Remote<T> {
             }
         };
 
-        let mut last_recv_time = Instant::now();
         let mut received = false;
         let conn_type = if self.handler.is_file_transfer() {
             ConnType::FILE_TRANSFER
@@ -219,6 +222,7 @@ impl<T: InvokeUiSession> Remote<T> {
                 let mut fps_instant = Instant::now();
 
                 let _keep_it = client::hc_connection(feedback, rendezvous_server, token).await;
+                let mut last_recv_time = Instant::now();
 
                 loop {
                     tokio::select! {
@@ -244,7 +248,7 @@ impl<T: InvokeUiSession> Remote<T> {
                             } else {
                                 if self.handler.is_restarting_remote_device() {
                                     log::info!("Restart remote device");
-                                    self.handler.msgbox("restarting", "Restarting remote device", "remote_restarting_tip", "");
+                                    self.handler.msgbox("restarting", "Restarting remote device", "Connection in progress. Please wait.", "");
                                 } else {
                                     log::info!("Reset by the peer");
                                     self.handler.msgbox("error", "Connection Error", "Reset by the peer", "");
@@ -279,6 +283,12 @@ impl<T: InvokeUiSession> Remote<T> {
                             }
                         }
                         _ = status_timer.tick() => {
+                            if self.handler.is_restarting_remote_device()
+                                && last_recv_time.elapsed() >= RESTART_REMOTE_DEVICE_NO_DATA_TIMEOUT
+                            {
+                                self.handler.msgbox("restarting-show", "Restarting remote device", "Connection in progress. Please wait.", "");
+                                break;
+                            }
                             let elapsed = fps_instant.elapsed().as_millis();
                             if elapsed < 1000 {
                                 continue;

src/ui_session_interface.rs

@@ -560,7 +560,7 @@ impl<T: InvokeUiSession> Session<T> {
 
     pub fn restart_remote_device(&self) {
         let mut lc = self.lc.write().unwrap();
-        lc.restarting_remote_device = true;
+        lc.mark_restarting_remote_device();
         let msg = lc.restart_remote_device();
         self.send(Data::Message(msg));
     }
@@ -656,7 +656,7 @@ impl<T: InvokeUiSession> Session<T> {
     }
 
     pub fn is_restarting_remote_device(&self) -> bool {
-        self.lc.read().unwrap().restarting_remote_device
+        self.lc.read().unwrap().is_restarting_remote_device()
     }
 
     #[inline]