fix(pulseaudio): derive client names for streams registering empty ones

Some clients (e.g. spotifyd) connect with empty media.name and
application.name, leaving them unnamed in the API and unaddressable
through the name-based action routes. Client names now fall back to
application.name then the process binary, applied consistently at parse
time and in the sink-input lookup; a failed lookup maps to 404.

Fixes #130

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01AKi5652rX9cdUDycdU1btS

Author: b0bbywan

backend/pulseaudio/pipewire.go

@@ -27,7 +27,7 @@ func (pa *PulseAudioBackend) parsePipeWireSinkInput(s pulseaudio.SinkInput) Audi
 
 	return AudioClient{
 		ID:      s.Index,
-		Name:    props["media.name"],
+		Name:    clientName(props),
 		App:     props["application.name"],
 		Muted:   s.IsMute(),
 		Volume:  s.GetVolume(),

backend/pulseaudio/pulseaudio.go

@@ -360,9 +360,9 @@ func (pa *PulseAudioBackend) SetVolumeMaster(volume float32) error {
 
 func (pa *PulseAudioBackend) ToggleMute(name string) error {
 	logger.Debug("[pulseaudio] toggling mute for client %q", name)
-	sink, err := pa.client.GetSinkInputByName(name)
+	sink, err := pa.findSinkInput(name)
 	if err != nil {
-		return fmt.Errorf("failed to get sink input: %w", err)
+		return err
 	}
 
 	if err := sink.ToggleMute(); err != nil {
@@ -373,9 +373,9 @@ func (pa *PulseAudioBackend) ToggleMute(name string) error {
 
 func (pa *PulseAudioBackend) SetVolume(name string, vol float32) error {
 	logger.Debug("[pulseaudio] setting volume for client %q to %.2f", name, vol)
-	sink, err := pa.client.GetSinkInputByName(name)
+	sink, err := pa.findSinkInput(name)
 	if err != nil {
-		return fmt.Errorf("failed to get sink input: %w", err)
+		return err
 	}
 
 	if err := sink.SetVolume(vol); err != nil {
@@ -385,6 +385,21 @@ func (pa *PulseAudioBackend) SetVolume(name string, vol float32) error {
 	return nil
 }
 
+// findSinkInput matches a sink input by the same derived name the parsers
+// expose, so clients registering empty names stay addressable.
+func (pa *PulseAudioBackend) findSinkInput(name string) (pulseaudio.SinkInput, error) {
+	inputs, err := pa.client.SinkInputs()
+	if err != nil {
+		return pulseaudio.SinkInput{}, fmt.Errorf("failed to list sink inputs: %w", err)
+	}
+	for _, s := range inputs {
+		if strings.EqualFold(clientName(s.PropList), name) {
+			return s, nil
+		}
+	}
+	return pulseaudio.SinkInput{}, &NotFoundError{Resource: "client", Name: name}
+}
+
 func (pa *PulseAudioBackend) parseSinkInput(s pulseaudio.SinkInput) AudioClient {
 	switch pa.kind {
 	case ServerPipeWire:
@@ -406,7 +421,7 @@ func (pa *PulseAudioBackend) parsePulseSinkInput(s pulseaudio.SinkInput) AudioCl
 
 	return AudioClient{
 		ID:      s.Index,
-		Name:    props["media.name"],
+		Name:    clientName(props),
 		App:     props["application.name"],
 		Muted:   s.IsMute(),
 		Volume:  s.GetVolume(),
@@ -419,6 +434,18 @@ func (pa *PulseAudioBackend) parsePulseSinkInput(s pulseaudio.SinkInput) AudioCl
 	}
 }
 
+// clientName is a client's routing and display name: media.name, falling back
+// to application.name then the process binary for streams that register empty
+// names (e.g. spotifyd).
+func clientName(props map[string]string) string {
+	for _, key := range []string{"media.name", "application.name", "application.process.binary"} {
+		if v := props[key]; v != "" {
+			return v
+		}
+	}
+	return ""
+}
+
 func detectServerKind(s *pulseaudio.Server) AudioServerKind {
 	if strings.Contains(strings.ToLower(s.PackageName), "pipewire") {
 		return ServerPipeWire

backend/pulseaudio/pulseaudio_test.go

@@ -652,3 +652,54 @@ func TestRemoveMissingClients(t *testing.T) {
 		})
 	}
 }
+
+// TestClientName verifies the naming fallback chain for streams that register
+// empty names (issue #130: spotifyd).
+func TestClientName(t *testing.T) {
+	tests := []struct {
+		name  string
+		props map[string]string
+		want  string
+	}{
+		{
+			name: "media.name wins",
+			props: map[string]string{
+				"media.name":                 "Playback",
+				"application.name":           "Spotify",
+				"application.process.binary": "spotify",
+			},
+			want: "Playback",
+		},
+		{
+			name: "application.name when media.name empty",
+			props: map[string]string{
+				"media.name":                 "",
+				"application.name":           "Spotify",
+				"application.process.binary": "spotify",
+			},
+			want: "Spotify",
+		},
+		{
+			name: "binary when both names empty",
+			props: map[string]string{
+				"media.name":                 "",
+				"application.name":           "",
+				"application.process.binary": "spotifyd",
+			},
+			want: "spotifyd",
+		},
+		{
+			name:  "everything empty",
+			props: map[string]string{},
+			want:  "",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := clientName(tt.props); got != tt.want {
+				t.Errorf("clientName() = %q, want %q", got, tt.want)
+			}
+		})
+	}
+}