plexus-mono 0.2.0

//! Playback engine — dedicated audio thread with queue management
//!
//! All rodio interaction is isolated to a single OS thread (OutputStream is !Send).
//! The Sink is Send+Sync and shared via Arc for control from async code.

use std::collections::{HashMap, VecDeque};
use std::path::PathBuf;
use std::sync::Arc;
use std::time::Duration;

use serde::{Deserialize, Serialize};
use tokio::sync::{watch, Mutex};

use crate::client::MonoClient;
use crate::types::{MonoEvent, PlayStatus, QueuedTrack};

/// Persisted player state — saved to disk so playback can resume across restarts
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct PlayerState {
    pub current_track: Option<QueuedTrack>,
    pub position_secs: f32,
    pub queue: Vec<QueuedTrack>,
    pub history: Vec<QueuedTrack>,
    pub volume: f32,
    #[serde(default = "default_preamp")]
    pub preamp: f32,
}

fn default_preamp() -> f32 {
    1.0
}

impl PlayerState {
    fn state_path() -> PathBuf {
        dirs::home_dir()
            .unwrap_or_else(|| PathBuf::from("."))
            .join(".plexus/monochrome/player/state.json")
    }

    pub fn load() -> Option<Self> {
        let path = Self::state_path();
        let data = std::fs::read_to_string(&path).ok()?;
        serde_json::from_str(&data).ok()
    }

    pub fn save(&self) {
        let path = Self::state_path();
        if let Some(parent) = path.parent() {
            let _ = std::fs::create_dir_all(parent);
        }
        if let Ok(json) = serde_json::to_string_pretty(self) {
            let _ = std::fs::write(&path, json);
        }
    }
}

/// Helper trait to erase the concrete StreamDownload type behind Box.
/// Rust doesn't allow `dyn Read + Seek + Send` (multiple non-auto traits),
/// so we combine them into one trait and blanket-implement it.
trait ReadSeekSend: std::io::Read + std::io::Seek + Send + Sync {}
impl<T: std::io::Read + std::io::Seek + Send + Sync> ReadSeekSend for T {}

/// Snapshot of current playback state, broadcast via watch channel
#[derive(Debug, Clone)]
pub struct NowPlaying {
    pub track_id: Option<u64>,
    pub title: Option<String>,
    pub artist: Option<String>,
    pub album: Option<String>,
    pub status: PlayStatus,
    pub position_secs: f32,
    pub duration_secs: f32,
    pub volume: f32,
    pub preamp: f32,
    pub queue_length: usize,
    pub url: Option<String>,
}

impl Default for NowPlaying {
    fn default() -> Self {
        Self {
            track_id: None,
            title: None,
            artist: None,
            album: None,
            status: PlayStatus::Idle,
            position_secs: 0.0,
            duration_secs: 0.0,
            volume: 1.0,
            preamp: 1.0,
            queue_length: 0,
            url: None,
        }
    }
}

struct PlayerInner {
    queue: VecDeque<QueuedTrack>,
    current_track: Option<QueuedTrack>,
    status: PlayStatus,
    volume: f32,
    preamp: f32,
    history: Vec<QueuedTrack>,
    /// Pre-buffered audio readers keyed by track ID.
    /// Each entry is a StreamDownload that's already connected and downloading.
    /// Dropped automatically when removed (temp file cleaned up via RAII).
    prefetched: HashMap<u64, Box<dyn ReadSeekSend>>,
}

/// Audio playback engine with queue and controls
pub struct Player {
    sink: Arc<rodio::Sink>,
    inner: Mutex<PlayerInner>,
    now_playing_tx: watch::Sender<NowPlaying>,
    now_playing_rx: watch::Receiver<NowPlaying>,
    client: Arc<MonoClient>,
    // Dropping this signals the audio thread to exit
    _shutdown_tx: std::sync::mpsc::Sender<()>,
}

impl Player {
    /// Create a new Player. Spawns a dedicated audio thread and background watchers.
    pub async fn new(client: Arc<MonoClient>) -> Arc<Self> {
        let (sink_tx, sink_rx) = std::sync::mpsc::channel();
        let (shutdown_tx, shutdown_rx) = std::sync::mpsc::channel::<()>();

        std::thread::spawn(move || {
            let (_stream, handle) = rodio::OutputStream::try_default()
                .expect("failed to open default audio output device");
            let sink = rodio::Sink::try_new(&handle)
                .expect("failed to create audio sink");
            let _ = sink_tx.send(sink);
            // Keep _stream alive until Player is dropped
            let _ = shutdown_rx.recv();
        });

        let sink = Arc::new(sink_rx.recv().expect("audio thread failed to initialize"));
        sink.pause(); // Start idle

        let (now_playing_tx, now_playing_rx) = watch::channel(NowPlaying::default());

        let player = Arc::new(Self {
            sink,
            inner: Mutex::new(PlayerInner {
                queue: VecDeque::new(),
                current_track: None,
                status: PlayStatus::Idle,
                volume: 1.0,
                preamp: 1.0,
                history: Vec::new(),
                prefetched: HashMap::new(),
            }),
            now_playing_tx,
            now_playing_rx,
            client,
            _shutdown_tx: shutdown_tx,
        });

        // Position reporter (~1s updates while playing)
        let weak = Arc::downgrade(&player);
        tokio::spawn(async move {
            loop {
                tokio::time::sleep(Duration::from_secs(1)).await;
                let Some(this) = weak.upgrade() else { break };
                let is_playing = {
                    let inner = this.inner.lock().await;
                    matches!(inner.status, PlayStatus::Playing)
                };
                if is_playing {
                    this.broadcast_now_playing().await;
                }
            }
        });

        // Track watcher — auto-advance when current track ends
        let weak = Arc::downgrade(&player);
        tokio::spawn(async move {
            loop {
                tokio::time::sleep(Duration::from_millis(250)).await;
                let Some(this) = weak.upgrade() else { break };
                if !this.sink.empty() {
                    continue;
                }
                let mut inner = this.inner.lock().await;
                if matches!(inner.status, PlayStatus::Playing) {
                    // Track ended naturally
                    if let Some(current) = inner.current_track.take() {
                        inner.history.push(current);
                    }
                    if let Some(next) = inner.queue.pop_front() {
                        inner.status = PlayStatus::Buffering;
                        drop(inner);
                        if let Err(e) = this.start_playback(next).await {
                            tracing::error!("auto-advance failed: {e}");
                            let mut inner = this.inner.lock().await;
                            inner.status = PlayStatus::Idle;
                            inner.current_track = None;
                            drop(inner);
                            this.broadcast_now_playing().await;
                        }
                        this.save_state().await;
                    } else {
                        inner.status = PlayStatus::Idle;
                        inner.current_track = None;
                        drop(inner);
                        this.broadcast_now_playing().await;
                        this.save_state().await;
                    }
                }
            }
        });

        // Prefetch watcher — pre-buffers queued tracks when playing
        let weak = Arc::downgrade(&player);
        tokio::spawn(async move {
            let mut last_track_id: Option<u64> = None;
            loop {
                tokio::time::sleep(Duration::from_secs(2)).await;
                let Some(this) = weak.upgrade() else { break };
                let current_id = {
                    let inner = this.inner.lock().await;
                    if !matches!(inner.status, PlayStatus::Playing) {
                        continue;
                    }
                    inner.current_track.as_ref().map(|t| t.id)
                };
                // Prefetch when track changes or on first play
                if current_id != last_track_id {
                    last_track_id = current_id;
                    this.prefetch_queue().await;
                }
            }
        });

        // OS media controls (play/pause keys, Now Playing widget)
        player.setup_media_controls();

        // Restore persisted state (queue, history, volume) from previous session
        player.restore_state().await;

        player
    }

    /// Wire up macOS Now Playing / media key integration via souvlaki.
    /// Spawns a dedicated thread that owns MediaControls and polls for
    /// metadata updates from the watch channel.
    fn setup_media_controls(self: &Arc<Self>) {
        use souvlaki::{
            MediaControlEvent, MediaControls, MediaMetadata, MediaPlayback, MediaPosition,
            PlatformConfig,
        };

        let tokio_handle = tokio::runtime::Handle::current();
        let weak = Arc::downgrade(self);
        let mut np_rx = self.subscribe_now_playing();

        std::thread::Builder::new()
            .name("media-controls".into())
            .spawn(move || {
                let config = PlatformConfig {
                    dbus_name: "plexus_mono",
                    display_name: "Plexus Mono",
                    hwnd: None,
                };
                let mut controls = match MediaControls::new(config) {
                    Ok(c) => c,
                    Err(e) => {
                        tracing::warn!("media controls unavailable: {e:?}");
                        return;
                    }
                };

                // Event handler — dispatches media key presses to player via tokio
                let weak2 = weak.clone();
                let handle = tokio_handle.clone();
                if let Err(e) = controls.attach(move |event: MediaControlEvent| {
                    let Some(player) = weak2.upgrade() else {
                        return;
                    };
                    let player = player.clone();
                    handle.spawn(async move {
                        match event {
                            MediaControlEvent::Play => player.resume().await,
                            MediaControlEvent::Pause => player.pause().await,
                            MediaControlEvent::Toggle => {
                                let is_playing = {
                                    let inner = player.inner.lock().await;
                                    matches!(inner.status, PlayStatus::Playing)
                                };
                                if is_playing {
                                    player.pause().await;
                                } else {
                                    player.resume().await;
                                }
                            }
                            MediaControlEvent::Next => {
                                let _ = player.next().await;
                            }
                            MediaControlEvent::Previous => {
                                let _ = player.previous().await;
                            }
                            _ => {}
                        }
                    });
                }) {
                    tracing::warn!("failed to attach media controls: {e:?}");
                    return;
                }

                tracing::info!("media controls active (Now Playing + media keys)");

                // Set initial state immediately to claim media keys from macOS
                let _ = controls.set_metadata(MediaMetadata {
                    title: Some("Plexus Mono"),
                    artist: None,
                    album: None,
                    duration: None,
                    cover_url: None,
                });
                let _ = controls.set_playback(MediaPlayback::Paused { progress: None });

                // Poll watch channel and update OS metadata
                loop {
                    std::thread::sleep(Duration::from_millis(500));

                    if !np_rx.has_changed().unwrap_or(false) {
                        // Also check if player is dropped
                        if weak.upgrade().is_none() {
                            break;
                        }
                        continue;
                    }

                    let np = np_rx.borrow_and_update().clone();

                    // Build cover art URL from Tidal cover UUID
                    let cover_url = np.title.as_ref().and_then(|_| {
                        // We don't have cover_id in NowPlaying, so skip for now
                        None::<String>
                    });

                    let _ = controls.set_metadata(MediaMetadata {
                        title: np.title.as_deref(),
                        artist: np.artist.as_deref(),
                        album: np.album.as_deref(),
                        duration: if np.duration_secs > 0.0 {
                            Some(Duration::from_secs_f32(np.duration_secs))
                        } else {
                            None
                        },
                        cover_url: cover_url.as_deref(),
                    });

                    let playback = match np.status {
                        PlayStatus::Playing => MediaPlayback::Playing {
                            progress: Some(MediaPosition(Duration::from_secs_f32(
                                np.position_secs,
                            ))),
                        },
                        PlayStatus::Paused => MediaPlayback::Paused {
                            progress: Some(MediaPosition(Duration::from_secs_f32(
                                np.position_secs,
                            ))),
                        },
                        _ => MediaPlayback::Stopped,
                    };
                    let _ = controls.set_playback(playback);
                }
            })
            .expect("failed to spawn media-controls thread");
    }

    /// Broadcast current state through the watch channel
    async fn broadcast_now_playing(&self) {
        let inner = self.inner.lock().await;
        let np = NowPlaying {
            track_id: inner.current_track.as_ref().map(|t| t.id),
            title: inner.current_track.as_ref().map(|t| t.title.clone()),
            artist: inner.current_track.as_ref().map(|t| t.artist.clone()),
            album: inner.current_track.as_ref().map(|t| t.album.clone()),
            status: inner.status.clone(),
            position_secs: self.sink.get_pos().as_secs_f32(),
            duration_secs: inner
                .current_track
                .as_ref()
                .map(|t| t.duration_secs as f32)
                .unwrap_or(0.0),
            volume: inner.volume,
            preamp: inner.preamp,
            queue_length: inner.queue.len(),
            url: inner.current_track.as_ref().map(|t| format!("https://monochrome.tf/track/t/{}", t.id)),
        };
        let _ = self.now_playing_tx.send(np);
    }

    /// Resolve stream URL, create decoder, and start playback on the sink.
    async fn start_playback(&self, track: QueuedTrack) -> Result<(), String> {
        {
            let mut inner = self.inner.lock().await;
            inner.current_track = Some(track.clone());
            inner.status = PlayStatus::Buffering;
        }
        self.broadcast_now_playing().await;

        // Check for a pre-buffered reader first
        let prefetched: Option<Box<dyn ReadSeekSend>> = {
            let mut inner = self.inner.lock().await;
            inner.prefetched.remove(&track.id)
        };

        let reader: Box<dyn ReadSeekSend> = if let Some(r) = prefetched {
            tracing::debug!("using prefetched audio for track {}", track.id);
            r
        } else {
            // Resolve CDN URL
            let manifest = self.client.stream_manifest(track.id, &track.quality).await?;
            let url = match &manifest {
                MonoEvent::StreamManifest { url, .. } => url.clone(),
                _ => return Err("unexpected manifest type".to_string()),
            };

            // Create streaming reader (async HTTP → Read+Seek buffer)
            let r = stream_download::StreamDownload::new_http(
                url.parse::<reqwest::Url>()
                    .map_err(|e| format!("bad stream url: {e}"))?,
                stream_download::storage::temp::TempStorageProvider::new(),
                stream_download::Settings::default(),
            )
            .await
            .map_err(|e| format!("stream download error: {e}"))?;
            Box::new(r)
        };

        // Decode on blocking thread (reads file headers from network buffer)
        let source = tokio::task::spawn_blocking(move || rodio::Decoder::new(reader))
            .await
            .map_err(|e| format!("decoder task panicked: {e}"))?
            .map_err(|e| format!("audio decode error: {e}"))?;

        // Stop previous audio, append new source, play
        self.sink.stop();
        self.sink.append(source);
        self.sink.play();

        {
            let mut inner = self.inner.lock().await;
            inner.status = PlayStatus::Playing;
        }
        self.broadcast_now_playing().await;

        Ok(())
    }

    /// Play a track immediately, stopping whatever is currently playing.
    pub async fn play_track(&self, id: u64, quality: &str) -> Result<(), String> {
        let track_info = self.client.track_info(id).await.ok();
        let queued = make_queued_track(id, quality, track_info);

        // Move current to history
        {
            let mut inner = self.inner.lock().await;
            if let Some(current) = inner.current_track.take() {
                inner.history.push(current);
            }
        }

        self.start_playback(queued).await
    }

    /// Pause playback
    pub async fn pause(&self) {
        self.sink.pause();
        let mut inner = self.inner.lock().await;
        if matches!(inner.status, PlayStatus::Playing | PlayStatus::Buffering) {
            inner.status = PlayStatus::Paused;
        }
        drop(inner);
        self.broadcast_now_playing().await;
    }

    /// Resume playback
    pub async fn resume(&self) {
        self.sink.play();
        let mut inner = self.inner.lock().await;
        if matches!(inner.status, PlayStatus::Paused) {
            inner.status = PlayStatus::Playing;
        }
        drop(inner);
        self.broadcast_now_playing().await;
    }

    /// Stop playback and clear current track
    pub async fn stop(&self) {
        self.sink.stop();
        let mut inner = self.inner.lock().await;
        if let Some(current) = inner.current_track.take() {
            inner.history.push(current);
        }
        inner.status = PlayStatus::Stopped;
        inner.prefetched.clear(); // Drop all pre-buffered temp files
        drop(inner);
        self.broadcast_now_playing().await;
        self.save_state().await;
    }

    /// Skip to next track in queue
    pub async fn next(&self) -> Result<(), String> {
        self.sink.stop();
        let next = {
            let mut inner = self.inner.lock().await;
            if let Some(current) = inner.current_track.take() {
                inner.history.push(current);
            }
            inner.queue.pop_front()
        };

        if let Some(track) = next {
            self.start_playback(track).await
        } else {
            let mut inner = self.inner.lock().await;
            inner.status = PlayStatus::Idle;
            drop(inner);
            self.broadcast_now_playing().await;
            Err("queue is empty".to_string())
        }
    }

    /// Go to previous track (from history), or restart current if >5s in
    pub async fn previous(&self) -> Result<(), String> {
        // If we're more than 5 seconds into the current track, restart it
        if self.sink.get_pos().as_secs_f32() > 5.0 {
            let track = {
                let inner = self.inner.lock().await;
                inner.current_track.clone()
            };
            if let Some(track) = track {
                return self.start_playback(track).await;
            }
        }

        self.sink.stop();
        let prev = {
            let mut inner = self.inner.lock().await;
            // Push current back to front of queue
            if let Some(current) = inner.current_track.take() {
                inner.queue.push_front(current);
            }
            inner.history.pop()
        };

        if let Some(track) = prev {
            self.start_playback(track).await
        } else {
            Err("no previous track".to_string())
        }
    }

    /// Apply combined volume (preamp × volume) to the sink
    fn apply_volume(&self, inner: &PlayerInner) {
        self.sink.set_volume(inner.preamp * inner.volume);
    }

    /// Set volume (0.0–1.0)
    pub async fn set_volume(&self, level: f32) {
        let level = level.clamp(0.0, 1.0);
        let mut inner = self.inner.lock().await;
        inner.volume = level;
        self.apply_volume(&inner);
        drop(inner);
        self.broadcast_now_playing().await;
        self.save_state().await;
    }

    /// Set pre-amp gain (0.0–4.0, where >1.0 boosts)
    pub async fn set_preamp(&self, level: f32) {
        let level = level.clamp(0.0, 4.0);
        let mut inner = self.inner.lock().await;
        inner.preamp = level;
        self.apply_volume(&inner);
        drop(inner);
        self.broadcast_now_playing().await;
        self.save_state().await;
    }

    /// Add a track to the end of the queue. Auto-starts if idle.
    pub async fn queue_add(&self, id: u64, quality: &str) -> Result<(), String> {
        let track_info = self.client.track_info(id).await.ok();
        let queued = make_queued_track(id, quality, track_info);

        let should_start = {
            let mut inner = self.inner.lock().await;
            let idle = matches!(inner.status, PlayStatus::Idle | PlayStatus::Stopped);
            if idle {
                // Will start this track directly
                true
            } else {
                inner.queue.push_back(queued.clone());
                false
            }
        };

        let result = if should_start {
            self.start_playback(queued).await
        } else {
            self.broadcast_now_playing().await;
            Ok(())
        };
        self.save_state().await;
        result
    }

    /// Add all tracks from an album to the queue. Auto-starts if idle.
    pub async fn queue_album(&self, album_id: u64, quality: &str) -> Result<Vec<QueuedTrack>, String> {
        let (_album_event, track_events) = self.client.album(album_id).await?;

        let mut queued_tracks = Vec::new();
        for event in &track_events {
            if let MonoEvent::AlbumTrack { id, title, artist, duration_secs, .. } = event {
                queued_tracks.push(QueuedTrack {
                    id: *id,
                    title: title.clone(),
                    artist: artist.clone(),
                    album: String::new(), // filled below
                    duration_secs: *duration_secs,
                    quality: quality.to_string(),
                    cover_id: None,
                });
            }
        }

        // Get album name from the album event
        let album_name = if let MonoEvent::Album { title, cover_id, .. } = &_album_event {
            for t in &mut queued_tracks {
                t.album = title.clone();
                t.cover_id = cover_id.clone();
            }
            title.clone()
        } else {
            format!("Album {album_id}")
        };

        if queued_tracks.is_empty() {
            return Err(format!("no tracks found in album {album_name}"));
        }

        let should_start = {
            let mut inner = self.inner.lock().await;
            let idle = matches!(inner.status, PlayStatus::Idle | PlayStatus::Stopped);
            if idle {
                // Queue all but the first; we'll start the first directly
                for t in queued_tracks.iter().skip(1) {
                    inner.queue.push_back(t.clone());
                }
                true
            } else {
                for t in &queued_tracks {
                    inner.queue.push_back(t.clone());
                }
                false
            }
        };

        if should_start {
            self.start_playback(queued_tracks[0].clone()).await?;
        } else {
            self.broadcast_now_playing().await;
        }

        Ok(queued_tracks)
    }

    /// Add multiple tracks to the queue at once. Auto-starts if idle.
    pub async fn queue_batch(&self, ids: &[u64], quality: &str) -> Result<Vec<QueuedTrack>, String> {
        if ids.is_empty() {
            return Err("no track IDs provided".into());
        }

        // Resolve all track metadata in parallel
        let futs: Vec<_> = ids.iter().map(|&id| {
            let client = self.client.clone();
            let q = quality.to_string();
            async move {
                let info = client.track_info(id).await.ok();
                make_queued_track(id, &q, info)
            }
        }).collect();
        let tracks: Vec<QueuedTrack> = futures::future::join_all(futs).await;

        let should_start = {
            let mut inner = self.inner.lock().await;
            let idle = matches!(inner.status, PlayStatus::Idle | PlayStatus::Stopped);
            if idle {
                // Queue all but the first; we'll start the first directly
                for t in tracks.iter().skip(1) {
                    inner.queue.push_back(t.clone());
                }
                true
            } else {
                for t in &tracks {
                    inner.queue.push_back(t.clone());
                }
                false
            }
        };

        if should_start {
            self.start_playback(tracks[0].clone()).await?;
        } else {
            self.broadcast_now_playing().await;
        }

        self.save_state().await;
        Ok(tracks)
    }

    /// Clear the queue (does not stop current track)
    pub async fn queue_clear(&self) {
        let mut inner = self.inner.lock().await;
        inner.queue.clear();
        inner.prefetched.clear(); // Drop all pre-buffered temp files
        drop(inner);
        self.broadcast_now_playing().await;
    }

    /// Get current track and queue contents
    pub async fn queue_get(&self) -> (Option<QueuedTrack>, Vec<QueuedTrack>) {
        let inner = self.inner.lock().await;
        (
            inner.current_track.clone(),
            inner.queue.iter().cloned().collect(),
        )
    }

    /// Reorder a track in the queue
    pub async fn queue_reorder(&self, from: usize, to: usize) -> Result<(), String> {
        let mut inner = self.inner.lock().await;
        if from >= inner.queue.len() || to >= inner.queue.len() {
            return Err(format!(
                "index out of bounds (queue has {} tracks)",
                inner.queue.len()
            ));
        }
        let track = inner.queue.remove(from).unwrap();
        inner.queue.insert(to, track);
        Ok(())
    }

    /// Pre-buffer queued tracks by resolving their stream URLs and starting downloads.
    /// Each StreamDownload writes to a temp file (cleaned up on drop via RAII).
    async fn prefetch_queue(&self) {
        let tracks: Vec<QueuedTrack> = {
            let inner = self.inner.lock().await;
            inner
                .queue
                .iter()
                .filter(|t| !inner.prefetched.contains_key(&t.id))
                .take(10)
                .cloned()
                .collect()
        };

        for track in tracks {
            // Resolve manifest
            let manifest = match self.client.stream_manifest(track.id, &track.quality).await {
                Ok(m) => m,
                Err(e) => {
                    tracing::debug!("prefetch manifest failed for {}: {e}", track.id);
                    continue;
                }
            };
            let url = match &manifest {
                MonoEvent::StreamManifest { url, .. } => url.clone(),
                _ => continue,
            };
            let parsed = match url.parse::<reqwest::Url>() {
                Ok(u) => u,
                Err(_) => continue,
            };

            // Start download — the temp file will buffer audio in the background
            let reader = match stream_download::StreamDownload::new_http(
                parsed,
                stream_download::storage::temp::TempStorageProvider::new(),
                stream_download::Settings::default(),
            )
            .await
            {
                Ok(r) => r,
                Err(e) => {
                    tracing::debug!("prefetch download failed for {}: {e}", track.id);
                    continue;
                }
            };

            tracing::debug!("prefetched track {} ({})", track.id, track.title);
            let mut inner = self.inner.lock().await;
            inner.prefetched.insert(track.id, Box::new(reader));
        }
    }

    /// Subscribe to now-playing updates
    pub fn subscribe_now_playing(&self) -> watch::Receiver<NowPlaying> {
        self.now_playing_rx.clone()
    }

    /// Snapshot current state for persistence
    pub async fn get_state(&self) -> PlayerState {
        let inner = self.inner.lock().await;
        PlayerState {
            current_track: inner.current_track.clone(),
            position_secs: self.sink.get_pos().as_secs_f32(),
            queue: inner.queue.iter().cloned().collect(),
            history: inner.history.clone(),
            volume: inner.volume,
            preamp: inner.preamp,
        }
    }

    /// Save current state to disk
    pub async fn save_state(&self) {
        let state = self.get_state().await;
        state.save();
    }

    /// Restore state from disk — resumes playback at the saved position
    pub async fn restore_state(&self) {
        if let Some(state) = PlayerState::load() {
            let resume_track = state.current_track.clone();
            let resume_pos = state.position_secs;

            {
                let mut inner = self.inner.lock().await;
                inner.queue = state.queue.into_iter().collect();
                inner.history = state.history;
                inner.volume = state.volume;
                inner.preamp = state.preamp;
                self.apply_volume(&inner);
            }

            // Resume the track that was playing, seeking to saved position
            if let Some(track) = resume_track {
                tracing::info!(
                    "resuming '{}' at {:.0}s",
                    track.title,
                    resume_pos
                );
                match self.start_playback(track).await {
                    Ok(()) => {
                        // Start paused so it doesn't blast on startup
                        self.sink.pause();
                        let mut inner = self.inner.lock().await;
                        inner.status = PlayStatus::Paused;
                        drop(inner);
                        self.broadcast_now_playing().await;
                    }
                    Err(e) => {
                        tracing::error!("failed to resume track: {e}");
                    }
                }
            } else {
                self.broadcast_now_playing().await;
            }

            tracing::info!("restored player state from disk");
        }
    }
}

/// Build a QueuedTrack from track info (or fallback to minimal metadata)
fn make_queued_track(id: u64, quality: &str, info: Option<MonoEvent>) -> QueuedTrack {
    match info {
        Some(MonoEvent::Track {
            title,
            artist,
            album,
            duration_secs,
            cover_id,
            ..
        }) => QueuedTrack {
            id,
            title,
            artist,
            album,
            duration_secs,
            quality: quality.to_string(),
            cover_id,
        },
        _ => QueuedTrack {
            id,
            title: format!("Track {id}"),
            artist: String::new(),
            album: String::new(),
            duration_secs: 0,
            quality: quality.to_string(),
            cover_id: None,
        },
    }
}