Fix inconsistent export download filenames (#24111)

* fix inconsistent export download filenames

Zip entries in a case download were named from `Export.name`, the friendly display name, while an individual download uses the file name on disk. The two have always been formatted differently, so one export came out as `front_door_20260823_020615-20260823_020734_abc123.mp4` on its own and `front door 2026-08-23 020615 2026-08-23 020734.mp4` inside a zip. Zip entries now use the on-disk file name, and renaming an export renames its file, so there's only one name to download under. The rename is blocked while ffmpeg still holds the file.

* cap filename length and catch duplicate names

* fix export rename and stop blocking the event loop

* move the rename rollback off the event loop

* no awaits

frigate/api/export.py

@@ -1,7 +1,9 @@
 """Export apis."""
 
+import contextlib
 import datetime
 import logging
+import os
 import random
 import string
 import time
@@ -15,7 +17,7 @@ import psutil
 from fastapi import APIRouter, Depends, Query, Request
 from fastapi.responses import JSONResponse, StreamingResponse
 from pathvalidate import sanitize_filename
-from peewee import DoesNotExist
+from peewee import DatabaseError, DoesNotExist, IntegrityError
 from playhouse.shortcuts import model_to_dict
 
 from frigate.api.auth import (
@@ -72,6 +74,7 @@ from frigate.record.export import (
     DEFAULT_TIME_LAPSE_FFMPEG_INPUT_ARGS,
     ChaptersEnum,
     PlaybackSourceEnum,
+    export_video_path,
     validate_ffmpeg_args,
 )
 from frigate.util.path import sanitize_contained_path
@@ -405,14 +408,17 @@ class _StreamingZipBuffer:
 
 
 def _unique_archive_name(export: Export, used: set[str]) -> str:
-    base = sanitize_filename(export.name) if export.name else None
-    if not base:
-        base = f"{export.camera}_{int(export.date)}"
+    """Zip entry name for an export, de-duplicated within the archive.
+
+    The on-disk name is the one the user sees either way: renaming an export
+    renames its file, so a zip entry and an individual download can't drift.
+    """
+    source = Path(export.video_path)
+    candidate = source.name
 
-    candidate = f"{base}.mp4"
     counter = 1
     while candidate in used:
-        candidate = f"{base}_{counter}.mp4"
+        candidate = f"{source.stem}_{counter}{source.suffix}"
         counter += 1
 
     used.add(candidate)
@@ -928,8 +934,59 @@ async def export_rename(event_id: str, body: ExportRenameBody, request: Request)
             status_code=404,
         )
 
+    if export.in_progress:
+        return JSONResponse(
+            content={
+                "success": False,
+                "message": "Export is still being written and can't be renamed yet.",
+            },
+            status_code=400,
+        )
+
+    new_path = export_video_path(body.name, export.id)
+    old_path = export.video_path
+    moved = new_path != old_path
+
+    # move the file first so a rename that can't happen leaves the row alone
+    if moved:
+        try:
+            os.rename(old_path, new_path)
+        except OSError:
+            logger.exception("Failed to rename export file for %s", event_id)
+            return JSONResponse(
+                content={"success": False, "message": "Failed to rename export."},
+                status_code=500,
+            )
+
     export.name = body.name
-    export.save()
+    export.video_path = new_path
+
+    try:
+        export.save()
+    except DatabaseError as err:
+        # the queue database has no transactions, so undo the move by hand
+        if moved:
+            with contextlib.suppress(OSError):
+                os.rename(new_path, old_path)
+
+        if isinstance(err, IntegrityError):
+            logger.warning(
+                "Export %s cannot be renamed, %s is taken", event_id, new_path
+            )
+            return JSONResponse(
+                content={
+                    "success": False,
+                    "message": "Another export already uses that name.",
+                },
+                status_code=409,
+            )
+
+        logger.exception("Failed to save renamed export %s", event_id)
+        return JSONResponse(
+            content={"success": False, "message": "Failed to rename export."},
+            status_code=500,
+        )
+
     return JSONResponse(
         content=(
             {