Add logs and richer panels to Textual dashboard

src/reactor_sim/textual_dashboard.py

@@ -79,6 +79,9 @@ class TextualDashboard(App):
         self._pending: deque[ReactorCommand] = deque()
         self._timer: Optional[Timer] = None
         self._trend_history: deque[tuple[float, float, float]] = deque(maxlen=120)
+        self.log_buffer: deque[str] = deque(maxlen=8)
+        self._log_handler: Optional[logging.Handler] = None
+        self._previous_handlers: list[logging.Handler] = []
         snap_at_env = os.getenv("FISSION_SNAPSHOT_AT")
         self.snapshot_at = float(snap_at_env) if snap_at_env else None
         self.snapshot_done = False
@@ -98,6 +101,7 @@ class TextualDashboard(App):
         self.maintenance_panel = Static(classes="panel")
         self.health_panel = Static(classes="panel")
         self.help_panel = Static(classes="panel")
+        self.log_panel = Static(classes="panel")
         self.status_panel = Static(classes="panel")
 
     def compose(self) -> ComposeResult:
@@ -117,11 +121,13 @@ class TextualDashboard(App):
                 yield self.protection_panel
                 yield self.maintenance_panel
                 yield self.health_panel
+                yield self.log_panel
                 yield self.help_panel
                 yield self.status_panel
         yield Footer()
 
     def on_mount(self) -> None:
+        self._install_log_capture()
         self._timer = self.set_interval(self.timestep, self._tick, pause=False)
         self._render_panels()
 
@@ -130,6 +136,7 @@ class TextualDashboard(App):
             self._timer.pause()
         if self.save_path and self.state:
             self.reactor.save_state(self.save_path, self.state)
+        self._restore_logging()
         self.exit()
 
     # Command helpers
@@ -260,6 +267,7 @@ class TextualDashboard(App):
         self.protection_panel.update(self._protection_text())
         self.maintenance_panel.update(self._maintenance_text())
         self.health_panel.update(self._health_text())
+        self.log_panel.update(self._log_text())
         self.help_panel.update(self._help_text())
         failures = ", ".join(self.reactor.health_monitor.failure_log) if self.reactor.health_monitor.failure_log else "None"
         self.status_panel.update(
@@ -388,6 +396,14 @@ class TextualDashboard(App):
         ]
         return "[bold cyan]Controls & Tips[/bold cyan]\\n" + "\\n".join(f"- {t}" for t in tips)
 
+    def _log_text(self) -> str:
+        lines = ["[bold cyan]Logs[/bold cyan]"]
+        if not self.log_buffer:
+            lines.append("No recent logs.")
+        else:
+            lines.extend(list(self.log_buffer))
+        return "\\n".join(lines)
+
     def _turbine_status_lines(self) -> list[str]:
         if not self.reactor.turbine_unit_active:
             return []
@@ -450,8 +466,29 @@ class TextualDashboard(App):
         except Exception as exc:  # pragma: no cover
             LOGGER.error("Failed to save snapshot: %s", exc)
 
+    def _install_log_capture(self) -> None:
+        logger = logging.getLogger("reactor_sim")
+        self._previous_handlers = list(logger.handlers)
+        handler = logging.StreamHandler()
+        handler.setLevel(logging.INFO)
+
+        def emit(record: logging.LogRecord) -> None:
+            msg = handler.format(record)
+            self.log_buffer.append(msg)
+
+        handler.emit = emit  # type: ignore[assignment]
+        logger.handlers = [handler]
+        logger.setLevel(logging.INFO)
+        self._log_handler = handler
+
+    def _restore_logging(self) -> None:
+        logger = logging.getLogger("reactor_sim")
+        if self._previous_handlers:
+            logger.handlers = self._previous_handlers
+        if self._log_handler and self._log_handler in logger.handlers:
+            logger.removeHandler(self._log_handler)
+
 
 def run_textual_dashboard(reactor: Reactor, start_state: Optional[PlantState], timestep: float, save_path: Optional[str]) -> None:
     app = TextualDashboard(reactor, start_state, timestep=timestep, save_path=save_path)
     app.run()
-