Migrate to Python daemon

src/recorder.py

@@ -0,0 +1,70 @@
+import os
+import signal
+import subprocess
+import tempfile
+import time
+from dataclasses import dataclass
+from pathlib import Path
+
+
+@dataclass
+class RecordResult:
+    wav_path: str
+    temp_dir: str
+
+
+def _resolve_ffmpeg_path(explicit: str) -> str:
+    if explicit:
+        return explicit
+    appdir = os.getenv("APPDIR")
+    if appdir:
+        candidate = Path(appdir) / "usr" / "bin" / "ffmpeg"
+        if candidate.exists():
+            return str(candidate)
+    return "ffmpeg"
+
+
+def _ffmpeg_input_args(spec: str) -> list[str]:
+    if not spec:
+        spec = "pulse:default"
+    kind = spec
+    name = "default"
+    if ":" in spec:
+        kind, name = spec.split(":", 1)
+    return ["-f", kind, "-i", name]
+
+
+def start_recording(ffmpeg_input: str, ffmpeg_path: str) -> tuple[subprocess.Popen, RecordResult]:
+    tmpdir = tempfile.mkdtemp(prefix="lel-")
+    wav = str(Path(tmpdir) / "mic.wav")
+
+    args = ["-hide_banner", "-loglevel", "error"]
+    args += _ffmpeg_input_args(ffmpeg_input)
+    args += ["-ac", "1", "-ar", "16000", "-c:a", "pcm_s16le", wav]
+
+    proc = subprocess.Popen(
+        [_resolve_ffmpeg_path(ffmpeg_path), *args],
+        preexec_fn=os.setsid,
+    )
+    return proc, RecordResult(wav_path=wav, temp_dir=tmpdir)
+
+
+def stop_recording(proc: subprocess.Popen, timeout_sec: float = 5.0) -> None:
+    if proc.poll() is None:
+        try:
+            os.killpg(proc.pid, signal.SIGINT)
+        except ProcessLookupError:
+            return
+    start = time.time()
+    while proc.poll() is None:
+        if time.time() - start > timeout_sec:
+            try:
+                os.killpg(proc.pid, signal.SIGKILL)
+            except ProcessLookupError:
+                pass
+            break
+        time.sleep(0.05)
+
+    # ffmpeg returns 255 on SIGINT; treat as success
+    if proc.returncode not in (0, 255, None):
+        raise RuntimeError(f"ffmpeg exited with status {proc.returncode}")