Refactor shared script helpers

tools/filenames.py

@@ -0,0 +1,32 @@
+from __future__ import annotations
+
+import re
+from datetime import datetime
+from pathlib import Path
+
+
+ORDERED_TIMESTAMP_STEM_RE = re.compile(r"^(?P<timestamp>\d{8}_\d{6})-[1-9]\d*$")
+
+
+def naive_wall_time(dt: datetime) -> datetime:
+    return dt.replace(tzinfo=None)
+
+
+def format_filename_stem(dt: datetime) -> str:
+    return naive_wall_time(dt).strftime("%Y%m%d_%H%M%S")
+
+
+def normalized_extension(path: Path) -> str:
+    return path.suffix.lower()
+
+
+def group_stem_from_name(name: str) -> str:
+    stem = Path(name).stem
+    match = ORDERED_TIMESTAMP_STEM_RE.match(stem)
+    if match:
+        return match.group("timestamp")
+    return stem
+
+
+def group_stem(path: Path) -> str:
+    return group_stem_from_name(path.name)