some fixes

python_app/gui/app_window.py

@@ -15,9 +15,10 @@ import logging
 import os
 from pathlib import Path
 import sys
+import threading
 import traceback
 
-from PyQt6.QtCore import QObject, QTimer, pyqtSignal
+from PyQt6.QtCore import QTimer
 from PyQt6.QtGui import QTextCursor
 from PyQt6.QtWidgets import QApplication, QMainWindow, QMessageBox
 
@@ -58,33 +59,60 @@ def _panel_extra(details: str | None, once_key: str | None) -> dict[str, object]
     return {"panel_details": details, "panel_once_key": once_key}
 
 
-class _PanelLogBridge(QObject):
-    """Marshals log records from any thread onto the GUI thread for panel rendering.
+class _PanelLogBuffer:
+    """Thread-safe bounded buffer between logging handlers and the GUI flush timer.
 
-    A :class:`logging.Handler` can fire on a worker thread (readers, broadcaster),
-    but the log widget may only be touched on the GUI thread; emitting this queued
-    signal hands the record across safely (the GPIO-button pattern).
+    A :class:`logging.Handler` can fire on a worker thread (readers, broadcaster)
+    at a very high rate — e.g. the USB RX threads while the free-running sweep
+    streams. Posting one queued Qt event per record used to flood the GUI event
+    queue and keep the interface frozen long after a blocking operation finished
+    while the backlog rendered. Instead, records land in this bounded buffer and
+    a periodic GUI-side timer drains them in one batch; overflow drops the oldest
+    records and reports how many were lost.
     """
 
-    record = pyqtSignal(str, str, object, object)  # display level, message, details, once_key
+    _CAPACITY = 2000
+
+    def __init__(self) -> None:
+        self._lock = threading.Lock()
+        self._entries: deque[tuple[str, str, str | None, str | None]] = deque(maxlen=self._CAPACITY)
+        self._dropped_count = 0
+
+    def append(self, level: str, text: str, details: str | None, once_key: str | None) -> None:
+        """Store one record, evicting the oldest when full (any thread)."""
+        with self._lock:
+            if len(self._entries) == self._CAPACITY:
+                self._dropped_count += 1
+            self._entries.append((level, text, details, once_key))
+
+    def drain(self) -> tuple[list[tuple[str, str, str | None, str | None]], int]:
+        """Return and clear all buffered records plus the overflow-drop count."""
+        with self._lock:
+            entries = list(self._entries)
+            self._entries.clear()
+            dropped_count = self._dropped_count
+            self._dropped_count = 0
+        return entries, dropped_count
 
 
 class _QtLogPanelHandler(logging.Handler):
     """Logging handler that forwards application log records to the GUI log panel."""
 
-    def __init__(self, bridge: _PanelLogBridge) -> None:
+    def __init__(self, buffer: _PanelLogBuffer) -> None:
         super().__init__()
-        self._bridge = bridge
+        self._buffer = buffer
 
     def emit(self, record: logging.LogRecord) -> None:
-        """Forward one record to the panel bridge, mapping WARNING to the short 'WARN'."""
+        """Buffer one record for the panel, mapping WARNING to the short 'WARN'."""
         try:
             display_level = "WARN" if record.levelname == "WARNING" else record.levelname
-            self._bridge.record.emit(
+            details = getattr(record, "panel_details", None)
+            once_key = getattr(record, "panel_once_key", None)
+            self._buffer.append(
                 display_level,
                 record.getMessage(),
-                getattr(record, "panel_details", None),
-                getattr(record, "panel_once_key", None),
+                details if isinstance(details, str) else None,
+                once_key if isinstance(once_key, str) else None,
             )
         except Exception:  # noqa: BLE001 - logging must never raise into the caller
             self.handleError(record)
@@ -145,23 +173,53 @@ class AppWindow(
         log_dir = self._project_root / "python_app/runtime/logs"
         configure_logging(level=DEFAULT_LOG_LEVEL, log_dir=log_dir, console=True)
         self._gui_logger = get_logger("gui")
-        self._log_panel_bridge = _PanelLogBridge()
-        self._log_panel_bridge.record.connect(self._on_log_record)
+        self._log_panel_buffer = _PanelLogBuffer()
 
     def _attach_log_panel(self) -> None:
         """Route application log records into the on-screen panel (widget now exists)."""
-        add_handler(_QtLogPanelHandler(self._log_panel_bridge))
+        add_handler(_QtLogPanelHandler(self._log_panel_buffer))
+        # One bounded flush per tick instead of one queued event per record: the
+        # panel can never flood the GUI event queue, no matter how chatty a
+        # DEBUG-level driver gets.
+        self._log_flush_timer = QTimer(self)
+        self._log_flush_timer.setInterval(100)
+        self._log_flush_timer.timeout.connect(self._flush_log_panel_buffer)
+        self._log_flush_timer.start()
 
-    def _on_log_record(self, level: str, text: str, details: object, once_key: object) -> None:
-        """Render one forwarded log record in the panel (always on the GUI thread)."""
-        if not hasattr(self, "_log_box"):
+    def _flush_log_panel_buffer(self) -> None:
+        """Render every buffered log record into the panel as one batched insert."""
+        entries, dropped_count = self._log_panel_buffer.drain()
+        if (not entries and not dropped_count) or not hasattr(self, "_log_box"):
             return
-        self._append_log_entry(
-            level,
-            text,
-            details=details if isinstance(details, str) else None,
-            once_key=once_key if isinstance(once_key, str) else None,
-        )
+
+        entry_htmls: list[str] = []
+        if dropped_count:
+            entry_htmls.append(
+                self._render_log_entry_html(
+                    "WARN",
+                    f"Log panel overflow: {dropped_count} record(s) dropped "
+                    "(they are still in the log file).",
+                )
+            )
+        error_seen = False
+        for level, text, details, once_key in entries:
+            if once_key is not None:
+                if once_key in self._logged_once_keys:
+                    continue
+                self._logged_once_keys.add(once_key)
+            entry_htmls.append(self._render_log_entry_html(level, text, details))
+            error_seen = error_seen or level.upper() == "ERROR"
+
+        if not entry_htmls:
+            return
+        cursor = self._log_box.textCursor()
+        cursor.movePosition(QTextCursor.MoveOperation.End)
+        self._log_box.setTextCursor(cursor)
+        self._log_box.insertHtml("".join(entry_htmls))
+        self._log_box.insertPlainText("\n")
+        self._log_box.ensureCursorVisible()
+        if error_seen and hasattr(self, "_status_label"):
+            self._status_label.setText("Status: error")
 
     def _init_runtime_services(self) -> None:
         """Initialize long-lived service objects used by mixins."""
@@ -266,6 +324,10 @@ class AppWindow(
     def _init_capture_state(self) -> None:
         """Initialize one-shot capture and sequence-control flags."""
         self._capture_session: SequentialCaptureSession | MultiRadarSequentialCaptureSession | None = None
+        # Guards the blocking per-combo capture against duplicate requests, and keeps
+        # the dialog's action buttons disabled until the post-capture input backlog
+        # is dropped (see AppWindowPreprocessMixin._begin/_end_preprocess_capture).
+        self._preprocess_capture_busy = False
         self._resume_pipeline_after_capture = False
         self._single_capture_active = False
         self._single_capture_start_ns: int | None = None
@@ -551,20 +613,8 @@ class AppWindow(
         """Return full chained traceback for error dialogs and log details."""
         return "".join(traceback.TracebackException.from_exception(exc).format(chain=True)).strip()
 
-    def _append_log_entry(
-        self,
-        level: str,
-        text: str,
-        *,
-        details: str | None = None,
-        once_key: str | None = None,
-    ) -> None:
-        """Append formatted log entry with timestamp and optional details."""
-        if once_key is not None:
-            if once_key in self._logged_once_keys:
-                return
-            self._logged_once_keys.add(once_key)
-
+    def _render_log_entry_html(self, level: str, text: str, details: str | None = None) -> str:
+        """Render one log entry as the panel's HTML block."""
         level_upper = level.upper()
         palette = {
             "DEBUG": ("#6c7b8d", "#52627a", "#8a97a8"),
@@ -586,16 +636,30 @@ class AppWindow(
                 "<pre style='margin:3px 0 0 16px; color:"
                 f"{detail_color};'>{html.escape(details)}</pre>"
             )
+        return "<div style='margin:0 0 6px 0;'>" + "".join(body_parts) + "</div>"
+
+    def _append_log_entry(
+        self,
+        level: str,
+        text: str,
+        *,
+        details: str | None = None,
+        once_key: str | None = None,
+    ) -> None:
+        """Append formatted log entry with timestamp and optional details."""
+        if once_key is not None:
+            if once_key in self._logged_once_keys:
+                return
+            self._logged_once_keys.add(once_key)
 
-        entry_html = "<div style='margin:0 0 6px 0;'>" + "".join(body_parts) + "</div>"
         cursor = self._log_box.textCursor()
         cursor.movePosition(QTextCursor.MoveOperation.End)
         self._log_box.setTextCursor(cursor)
-        self._log_box.insertHtml(entry_html)
+        self._log_box.insertHtml(self._render_log_entry_html(level, text, details))
         self._log_box.insertPlainText("\n")
         self._log_box.ensureCursorVisible()
 
-        if level_upper == "ERROR" and hasattr(self, "_status_label"):
+        if level.upper() == "ERROR" and hasattr(self, "_status_label"):
             self._status_label.setText("Status: error")
 
     def _on_log_level_selected(self, level_text: str) -> None: