Detach tone-test savers on reconnect

tonetest.go

@@ -65,10 +65,11 @@ func StartToneGenerator(client *gumble.Client, stop <-chan struct{}) {
 // AudioFileSaver implements gumble.AudioListener and writes all incoming PCM
 // audio to a single raw 16-bit little-endian stereo 48kHz file.
 type AudioFileSaver struct {
-	file *os.File
-	stop chan struct{}
-	mu   sync.Mutex
-	wg   sync.WaitGroup
+	file    *os.File
+	stop    chan struct{}
+	mu      sync.Mutex
+	stopped bool
+	wg      sync.WaitGroup
 }
 
 // NewAudioFileSaver creates the output file and returns a configured saver.
@@ -95,15 +96,32 @@ func NewAudioFileSaver(path string) (*AudioFileSaver, error) {
 // Stop closes the stop channel, waits for all stream goroutines to finish,
 // and closes the output file.
 func (s *AudioFileSaver) Stop() {
+	s.mu.Lock()
+	if s.stopped {
+		s.mu.Unlock()
+		return
+	}
+	s.stopped = true
 	close(s.stop)
+	s.mu.Unlock()
+
 	s.wg.Wait()
-	s.file.Close()
+	s.mu.Lock()
+	_ = s.file.Close()
+	s.mu.Unlock()
 }
 
 // OnAudioStream implements gumble.AudioListener.
 func (s *AudioFileSaver) OnAudioStream(e *gumble.AudioStreamEvent) {
-	fmt.Fprintf(os.Stderr, "tonetest: incoming audio stream from %s\n", e.User.Name)
+	s.mu.Lock()
+	if s.stopped {
+		s.mu.Unlock()
+		return
+	}
 	s.wg.Add(1)
+	s.mu.Unlock()
+
+	fmt.Fprintf(os.Stderr, "tonetest: incoming audio stream from %s\n", e.User.Name)
 	go func() {
 		defer s.wg.Done()