[fix] delay signaling offline indication during reconnects

apps/desktop/src/gui/application/gui_application.cpp

@@ -74,6 +74,10 @@ namespace {
 
 using namespace std::chrono_literals;
 
+// Median reconnect to the signal server lands around 7 s on a lossy path, so a
+// drop shorter than this is almost always already being recovered from.
+constexpr auto kSignalOfflineGrace = 10s;
+
 std::optional<std::string> GenerateRandomPassword(std::string_view current) {
   constexpr std::string_view alphabet =
       "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
@@ -2471,7 +2475,21 @@ void GuiApplication::SyncMainWindow() {
     std::lock_guard<std::mutex> lock(password_change_mutex_);
     ui_->main->set_password_change_pending(password_change_pending_);
   }
-  ui_->main->set_signal_connected(signal_connected_);
+  const bool signal_online = signal_connected_.load();
+  if (signal_online) {
+    signal_lost_at_valid_ = false;
+  } else if (!signal_lost_at_valid_) {
+    signal_lost_at_ = std::chrono::steady_clock::now();
+    signal_lost_at_valid_ = true;
+  }
+  // Reconnects routinely take several seconds on a lossy path; only report
+  // offline once the connection has stayed down long enough to be a real
+  // outage rather than a blip the reconnect is already recovering from.
+  const bool signal_offline =
+      !signal_online && signal_lost_at_valid_ &&
+      std::chrono::steady_clock::now() - signal_lost_at_ >
+          kSignalOfflineGrace;
+  ui_->main->set_signal_connected(!signal_offline);
   ui_->main->set_signal_tls_error(signal_status_ ==
                                   SignalStatus::SignalTlsCertError);
   ui_->main->set_update_available(update_available_);

apps/desktop/src/gui/application/gui_application.h

@@ -106,6 +106,11 @@ private:
       cursor_delivery_states_;
   uint32_t cursor_state_sequence_ = 0;
   std::chrono::steady_clock::time_point next_video_frame_time_{};
+  // The signal server is reached over a lossy path that routinely drops for the
+  // few seconds a reconnect takes, so the main window holds its "connected"
+  // indication through a brief blip instead of flickering offline.
+  std::chrono::steady_clock::time_point signal_lost_at_{};
+  bool signal_lost_at_valid_ = false;
 #if defined(__linux__) && !defined(__APPLE__)
   bool use_xwayland_gui_ = false;
   bool use_x11_custom_titlebar_ = false;