fix: drop audio stream when idle to allow system suspend (#54)

* fix: drop audio stream when idle to allow system suspend

The daemon kept its ALSA playback stream open permanently, which
PipeWire reported as a running Stream/Output/Audio node even with
no tracks playing. This prevented desktop environments from detecting
idle state and entering suspend.

- Make the audio sink on-demand: created when playback starts,
  dropped when all tracks finish
- Reduce player loop polling from 100ms to 2s when idle
- Throttle PipeWire device enumeration to every ~5s while playing
- Log only first and last link retry attempt instead of all 60

src/bin/daemon.rs

@@ -40,7 +40,11 @@ async fn main() -> Result<(), Box<dyn Error>> {
                     println!("Successfully linked player to virtual mic.");
                     break;
                 }
-                Err(e) => println!("{e}\t{i}/{max_retries}"),
+                Err(e) => {
+                    if i == 0 || i == max_retries {
+                        eprintln!("{e} (attempt {i}/{max_retries})");
+                    }
+                }
             }
 
             sleep(Duration::from_millis(1000)).await;
@@ -174,19 +178,25 @@ async fn commands_loop(listener: UnixListener) -> Result<(), Box<dyn Error>> {
 }
 
 async fn player_loop() {
+    let mut device_check_counter: u32 = 0;
     loop {
-        match get_audio_player().await {
+        let is_idle = match get_audio_player().await {
             Ok(player_mutex) => {
                 let mut audio_player = player_mutex.lock().await;
-                audio_player.update().await;
+                let check_devices = device_check_counter == 0;
+                audio_player.update(check_devices).await;
+                audio_player.tracks.is_empty()
             }
-            Err(_err) => {
-                // To avoid spamming logs every 100ms when audio player fails to init
-                // we can just sleep, or you might prefer to print the error.
-                // Assuming it failed to initialize, no player update is possible.
-            }
-        }
+            Err(_err) => true,
+        };
 
-        sleep(Duration::from_millis(100)).await;
+        if is_idle {
+            device_check_counter = 0;
+            sleep(Duration::from_secs(2)).await;
+        } else {
+            // Check devices every ~5 seconds (50 * 100ms) while playing
+            device_check_counter = (device_check_counter + 1) % 50;
+            sleep(Duration::from_millis(100)).await;
+        }
     }
 }

src/types/audio_player.rs

@@ -53,7 +53,7 @@ pub struct PlayingSound {
 }
 
 pub struct AudioPlayer {
-    pub stream_handle: MixerDeviceSink,
+    stream_handle: Option<MixerDeviceSink>,
     pub tracks: HashMap<u32, PlayingSound>,
     pub next_id: u32,
 
@@ -68,10 +68,8 @@ impl AudioPlayer {
         let daemon_config = get_daemon_config();
         let default_volume = daemon_config.default_volume.unwrap_or(1.0);
 
-        let stream_handle = DeviceSinkBuilder::open_default_sink()?;
-
         let mut audio_player = AudioPlayer {
-            stream_handle,
+            stream_handle: None,
             tracks: HashMap::new(),
             next_id: 1,
 
@@ -88,6 +86,21 @@ impl AudioPlayer {
         Ok(audio_player)
     }
 
+    fn ensure_stream(&mut self) -> Result<&MixerDeviceSink, Box<dyn Error>> {
+        if self.stream_handle.is_none() {
+            let mut sink = DeviceSinkBuilder::open_default_sink()?;
+            sink.log_on_drop(false);
+            self.stream_handle = Some(sink);
+        }
+        Ok(self.stream_handle.as_ref().unwrap())
+    }
+
+    fn drop_stream(&mut self) {
+        if self.stream_handle.is_some() {
+            self.stream_handle = None;
+        }
+    }
+
     fn abort_link_thread(&mut self) {
         if let Some(sender) = &self.input_link_sender {
             match sender.send(Terminate {}) {
@@ -179,6 +192,9 @@ impl AudioPlayer {
         } else {
             self.tracks.clear();
         }
+        if self.tracks.is_empty() {
+            self.drop_stream();
+        }
     }
 
     pub fn is_paused(&self) -> bool {
@@ -299,12 +315,15 @@ impl AudioPlayer {
                     self.tracks.clear();
                 }
 
+                self.ensure_stream()?;
+
                 let id = self.next_id;
                 self.next_id += 1;
 
                 let duration = source.total_duration().map(|d| d.as_secs_f32());
 
-                let sink = Player::connect_new(self.stream_handle.mixer());
+                let mixer = self.stream_handle.as_ref().unwrap().mixer();
+                let sink = Player::connect_new(mixer);
                 sink.set_volume(self.volume); // Default volume is 1.0 * master
                 sink.append(source);
                 sink.play();
@@ -358,20 +377,23 @@ impl AudioPlayer {
         tracks
     }
 
-    pub async fn update(&mut self) {
-        if let Some(input_device_name) = &self.input_device_name {
-            // Unlink devices if selected input device was removed
-            if self.input_link_sender.is_some() && get_device(input_device_name).await.is_err() {
-                // Selected input device was removed
-                eprintln!(
-                    "Selected input device {} was removed, unlinking devices",
-                    input_device_name
-                );
-                self.abort_link_thread();
-            }
-            // Link devices if not linked
-            else if self.input_link_sender.is_none() {
-                self.link_devices().await.ok();
+    pub async fn update(&mut self, check_devices: bool) {
+        if check_devices {
+            if let Some(input_device_name) = &self.input_device_name {
+                // Unlink devices if selected input device was removed
+                if self.input_link_sender.is_some()
+                    && get_device(input_device_name).await.is_err()
+                {
+                    eprintln!(
+                        "Selected input device {} was removed, unlinking devices",
+                        input_device_name
+                    );
+                    self.abort_link_thread();
+                }
+                // Link devices if not linked
+                else if self.input_link_sender.is_none() {
+                    self.link_devices().await.ok();
+                }
             }
         }
 
@@ -412,6 +434,10 @@ impl AudioPlayer {
 
         self.tracks
             .retain(|_, sound| !sound.sink.empty() || sound.looped);
+
+        if self.tracks.is_empty() {
+            self.drop_stream();
+        }
     }
 
     pub async fn set_current_input_device(&mut self, name: &str) -> Result<(), Box<dyn Error>> {