Merge branch 'feat/dev-debug-window'

1 files changed, 65 insertions, 0 deletions

diff --git a/core/debug_log.py b/core/debug_log.py
new file mode 100644
index 0000000..86a8a59
--- /dev/null
+++ b/core/debug_log.py
@@ -0,0 +1,65 @@
+"""
+core/debug_log.py
+
+Tees stdout/stderr into an in-memory ring buffer + Qt signal so the Debug
+window can show everything the app has printed since startup — including
+messages from background poll threads (e.g. "[CMLLayer] poll error: ...") —
+not just whatever gets printed while the window happens to be open.
+
+install() should be called once, early, before anything prints. The real
+streams are still written to, so running from a terminal is unaffected.
+"""
+
+from __future__ import annotations
+
+import sys
+from collections import deque
+from typing import Optional
+
+from PyQt6.QtCore import QObject, pyqtSignal
+
+
+class _Broadcaster(QObject):
+    line_written = pyqtSignal(str)
+
+
+class _StreamTee:
+    def __init__(self, real_stream, lines: deque, broadcaster: _Broadcaster):
+        self._real        = real_stream
+        self._lines       = lines
+        self._broadcaster = broadcaster
+
+    def write(self, text: str) -> None:
+        self._real.write(text)
+        if text:
+            self._lines.append(text)
+            self._broadcaster.line_written.emit(text)
+
+    def flush(self) -> None:
+        self._real.flush()
+
+    def isatty(self) -> bool:
+        return False
+
+
+_lines:       Optional[deque]       = None
+_broadcaster: Optional[_Broadcaster] = None
+
+
+def install(max_lines: int = 2000) -> None:
+    """Redirect sys.stdout/sys.stderr through the tee. Safe to call once."""
+    global _lines, _broadcaster
+    if _broadcaster is not None:
+        return
+    _lines       = deque(maxlen=max_lines)
+    _broadcaster = _Broadcaster()
+    sys.stdout   = _StreamTee(sys.stdout, _lines, _broadcaster)
+    sys.stderr   = _StreamTee(sys.stderr, _lines, _broadcaster)
+
+
+def get_broadcaster() -> Optional[_Broadcaster]:
+    return _broadcaster
+
+
+def get_history() -> str:
+    return "".join(_lines) if _lines is not None else ""