fix: wait for finalized wav header before transcription

bot.py

@@ -4,6 +4,7 @@ import asyncio
 import logging
 import os
 import uuid
+import wave
 from pathlib import Path
 
 import discord
@@ -136,8 +137,18 @@ async def wait_for_file_ready(file_path: str, attempts: int = 20, delay: float =
             if size > 0 and size == last_size:
                 stable_count += 1
                 if stable_count >= 2:
-                    logger.info("Recording file finalized: path=%s size_bytes=%s", file_path, size)
-                    return True
+                    try:
+                        with wave.open(file_path, "rb") as wav_file:
+                            wav_file.getparams()
+                    except (wave.Error, EOFError, OSError) as exc:
+                        logger.info(
+                            "Recording file exists and is size-stable but WAV header is not finalized yet: path=%s error=%s",
+                            file_path,
+                            exc,
+                        )
+                    else:
+                        logger.info("Recording file finalized: path=%s size_bytes=%s", file_path, size)
+                        return True
             else:
                 stable_count = 0
                 last_size = size

tests/test_bot.py

@@ -1,6 +1,7 @@
 import asyncio
 import os
 import sys
+import wave
 from pathlib import Path
 from types import SimpleNamespace
 
@@ -106,3 +107,25 @@ def test_meeting_recorder_wraps_wave_sink_with_silence_generator(tmp_path, monke
     assert created["silence"].destination is created["wave"]
     assert vc.listened_sink is created["silence"]
     assert recorder.recording is True
+
+
+def test_wait_for_file_ready_rejects_stable_but_invalid_wav(tmp_path):
+    broken = tmp_path / "meeting.wav"
+    broken.write_bytes(b"not a real wav file")
+
+    ready = asyncio.run(bot.wait_for_file_ready(str(broken), attempts=3, delay=0.001))
+
+    assert ready is False
+
+
+def test_wait_for_file_ready_accepts_valid_wav(tmp_path):
+    valid = tmp_path / "meeting.wav"
+    with wave.open(str(valid), "wb") as wav_file:
+        wav_file.setnchannels(1)
+        wav_file.setsampwidth(2)
+        wav_file.setframerate(16000)
+        wav_file.writeframes(b"\x00\x00" * 160)
+
+    ready = asyncio.run(bot.wait_for_file_ready(str(valid), attempts=3, delay=0.001))
+
+    assert ready is True