app: add auto-reconnect with backoff

src/tuimble/app.py

@@ -14,7 +14,7 @@ from textual.reactive import reactive
 from textual.widgets import Footer, Header, Input, RichLog, Static
 
 from tuimble.audio import AudioPipeline
-from tuimble.client import Channel, MumbleClient, User
+from tuimble.client import Channel, ConnectionFailed, MumbleClient, User
 from tuimble.config import Config, load_config
 from tuimble.ptt import KittyPtt, TogglePtt, detect_backend
 
@@ -22,6 +22,10 @@ log = logging.getLogger(__name__)
 
 VOLUME_STEPS = (0.0, 0.25, 0.5, 0.75, 1.0, 1.25, 1.5, 2.0)
 
+RECONNECT_INITIAL = 2    # seconds before first retry
+RECONNECT_MAX = 30       # maximum backoff delay
+RECONNECT_RETRIES = 10   # attempts before giving up
+
 
 def _next_volume(current: float) -> float:
     """Cycle through VOLUME_STEPS, wrapping to 0.0 after max."""
@@ -404,6 +408,9 @@ class TuimbleApp(App):
         self._audio.input_gain = acfg.input_gain
         self._audio.output_gain = acfg.output_gain
         self._pending_reload: Config | None = None
+        self._reconnecting: bool = False
+        self._reconnect_attempt: int = 0
+        self._intentional_disconnect: bool = False
 
     def compose(self) -> ComposeResult:
         yield Header()
@@ -428,8 +435,8 @@ class TuimbleApp(App):
 
     # -- server connection (worker thread) -----------------------------------
 
-    @work(thread=True)
-    def _connect_to_server(self) -> None:
+    def _wire_client_callbacks(self) -> None:
+        """Wire pymumble callbacks to message dispatchers."""
         self._client.set_dispatcher(self.call_from_thread)
         self._client.on_connected = self._cb_connected
         self._client.on_disconnected = self._cb_disconnected
@@ -438,6 +445,9 @@ class TuimbleApp(App):
         self._client.on_channel_update = self._cb_state_changed
         self._client.on_sound_received = self._cb_sound_received
 
+    @work(thread=True)
+    def _connect_to_server(self) -> None:
+        self._wire_client_callbacks()
         try:
             self._client.connect()
         except Exception as exc:
@@ -462,9 +472,101 @@ class TuimbleApp(App):
         chatlog = self.query_one("#chatlog", ChatLog)
         chatlog.write(f"[#f7768e]\u2717 {text}[/]")
 
+    # -- auto-reconnect ------------------------------------------------------
+
+    @work(thread=True)
+    def _reconnect_loop(self) -> None:
+        """Retry connection with exponential backoff."""
+        while self._reconnecting:
+            self._reconnect_attempt += 1
+            delay = min(
+                RECONNECT_INITIAL * (2 ** (self._reconnect_attempt - 1)),
+                RECONNECT_MAX,
+            )
+            self.call_from_thread(
+                self._log_reconnect, self._reconnect_attempt, delay,
+            )
+
+            elapsed = 0.0
+            while elapsed < delay and self._reconnecting:
+                time.sleep(0.5)
+                elapsed += 0.5
+
+            if not self._reconnecting:
+                break
+
+            try:
+                self._client.disconnect()
+                srv = self._config.server
+                self._client = MumbleClient(
+                    host=srv.host,
+                    port=srv.port,
+                    username=srv.username,
+                    password=srv.password,
+                    certfile=srv.certfile,
+                    keyfile=srv.keyfile,
+                )
+                self._wire_client_callbacks()
+                self._client.connect()
+
+                self._reconnecting = False
+                self._reconnect_attempt = 0
+                self.call_from_thread(self._on_reconnect_success)
+                return
+            except ConnectionFailed as exc:
+                if not exc.retryable:
+                    self.call_from_thread(
+                        self._show_error, f"rejected: {exc}",
+                    )
+                    self._reconnecting = False
+                    self.call_from_thread(self._on_reconnect_exhausted)
+                    return
+                self.call_from_thread(
+                    self._show_error,
+                    f"attempt {self._reconnect_attempt}: {exc}",
+                )
+            except Exception as exc:
+                self.call_from_thread(
+                    self._show_error,
+                    f"attempt {self._reconnect_attempt}: {exc}",
+                )
+
+            if self._reconnect_attempt >= RECONNECT_RETRIES:
+                self._reconnecting = False
+                self.call_from_thread(self._on_reconnect_exhausted)
+                return
+
+    def _log_reconnect(self, attempt: int, delay: int) -> None:
+        """Log reconnection attempt to chatlog."""
+        chatlog = self.query_one("#chatlog", ChatLog)
+        chatlog.write(
+            f"[dim]reconnecting in {delay}s "
+            f"(attempt {attempt}/{RECONNECT_RETRIES})...[/dim]"
+        )
+
+    def _on_reconnect_success(self) -> None:
+        """Handle successful reconnection."""
+        self.post_message(ServerConnected())
+
+    def _on_reconnect_exhausted(self) -> None:
+        """Handle all reconnection attempts exhausted."""
+        chatlog = self.query_one("#chatlog", ChatLog)
+        chatlog.write(
+            f"[#f7768e]reconnection failed after "
+            f"{RECONNECT_RETRIES} attempts[/]"
+        )
+        chatlog.write("[dim]press F5 to retry manually[/dim]")
+
+    def _cancel_reconnect(self) -> None:
+        """Cancel an in-progress reconnect loop."""
+        self._reconnecting = False
+        self._reconnect_attempt = 0
+
     # -- message handlers ----------------------------------------------------
 
     def on_server_connected(self, _msg: ServerConnected) -> None:
+        self._intentional_disconnect = False
+
         status = self.query_one("#status", StatusBar)
         status.connected = True
         srv = self._config.server
@@ -484,11 +586,18 @@ class TuimbleApp(App):
         status.connected = False
         status.server_info = ""
 
+        tree = self.query_one("#sidebar", ChannelTree)
+        tree.clear_state()
+
+        if self._intentional_disconnect or self._reconnecting:
+            return
+
         chatlog = self.query_one("#chatlog", ChatLog)
         chatlog.write("[#f7768e]\u2717 disconnected from server[/]")
 
-        tree = self.query_one("#sidebar", ChannelTree)
-        tree.clear_state()
+        self._reconnecting = True
+        self._reconnect_attempt = 0
+        self._reconnect_loop()
 
     def on_text_message_received(self, msg: TextMessageReceived) -> None:
         chatlog = self.query_one("#chatlog", ChatLog)
@@ -683,6 +792,8 @@ class TuimbleApp(App):
         )
 
         if server_changed:
+            self._intentional_disconnect = True
+            self._cancel_reconnect()
             self._audio.stop()
             self._client.set_dispatcher(None)
             self._client.disconnect()
@@ -720,7 +831,31 @@ class TuimbleApp(App):
             chatlog.write("[dim]audio pipeline restarted[/dim]")
 
     def action_reload_config(self) -> None:
-        """Reload config from disk (F5)."""
+        """Reload config from disk (F5).
+
+        Also serves as manual reconnect when disconnected.
+        """
+        if self._reconnecting:
+            self._cancel_reconnect()
+
+        if not self._client.connected:
+            chatlog = self.query_one("#chatlog", ChatLog)
+            srv = self._config.server
+            self._client = MumbleClient(
+                host=srv.host,
+                port=srv.port,
+                username=srv.username,
+                password=srv.password,
+                certfile=srv.certfile,
+                keyfile=srv.keyfile,
+            )
+            chatlog.write(
+                f"[dim]connecting to {srv.host}:{srv.port}...[/dim]"
+            )
+            self._intentional_disconnect = False
+            self._connect_to_server()
+            return
+
         chatlog = self.query_one("#chatlog", ChatLog)
 
         if self._pending_reload is not None:
@@ -828,6 +963,8 @@ class TuimbleApp(App):
     # -- lifecycle -----------------------------------------------------------
 
     def action_quit(self) -> None:
+        self._intentional_disconnect = True
+        self._cancel_reconnect()
         self._audio.stop()
         self._client.set_dispatcher(None)
         self._client.disconnect()