Merge pull request #305 from dweymouth/feature/jukebox

Redesign of PlaybackManager

backend/app.go

@@ -12,6 +12,7 @@ import (
 
 	"github.com/dweymouth/supersonic/backend/util"
 	"github.com/dweymouth/supersonic/player"
+	"github.com/dweymouth/supersonic/player/mpv"
 	"github.com/dweymouth/supersonic/sharedutil"
 	"github.com/fsnotify/fsnotify"
 	"github.com/google/uuid"
@@ -36,7 +37,7 @@ type App struct {
 	ServerManager   *ServerManager
 	ImageManager    *ImageManager
 	PlaybackManager *PlaybackManager
-	Player          *player.Player
+	LocalPlayer     *mpv.Player
 	UpdateChecker   UpdateChecker
 	MPRISHandler    *MPRISHandler
 
@@ -107,7 +108,7 @@ func StartupApp(appName, displayAppName, appVersionTag, configFile, latestReleas
 	}
 
 	a.ServerManager = NewServerManager(appName, a.Config)
-	a.PlaybackManager = NewPlaybackManager(a.bgrndCtx, a.ServerManager, a.Player, &a.Config.Scrobbling, &a.Config.Transcoding)
+	a.PlaybackManager = NewPlaybackManager(a.bgrndCtx, a.ServerManager, a.LocalPlayer, &a.Config.Scrobbling, &a.Config.Transcoding)
 	a.ImageManager = NewImageManager(a.bgrndCtx, a.ServerManager, configdir.LocalCache(a.appName))
 	a.Config.Application.MaxImageCacheSizeMB = clamp(a.Config.Application.MaxImageCacheSizeMB, 1, 500)
 	a.ImageManager.SetMaxOnDiskCacheSizeBytes(int64(a.Config.Application.MaxImageCacheSizeMB) * 1_048_576)
@@ -117,7 +118,7 @@ func StartupApp(appName, displayAppName, appVersionTag, configFile, latestReleas
 
 	// OS media center integrations
 	a.setupMPRIS(displayAppName)
-	InitMPMediaHandler(a.Player, a.PlaybackManager, func(id string) (string, error) {
+	InitMPMediaHandler(a.PlaybackManager, func(id string) (string, error) {
 		a.ImageManager.GetCoverThumbnail(id) // ensure image is cached locally
 		return a.ImageManager.GetCoverArtUrl(id)
 	})
@@ -194,21 +195,21 @@ func (a *App) callOnReactivate() {
 }
 
 func (a *App) initMPV() error {
-	p := player.NewWithClientName(a.appName)
+	p := mpv.NewWithClientName(a.appName)
 	c := a.Config.LocalPlayback
 	c.InMemoryCacheSizeMB = clamp(c.InMemoryCacheSizeMB, 10, 500)
 	if err := p.Init(c.InMemoryCacheSizeMB); err != nil {
 		return fmt.Errorf("failed to initialize mpv player: %s", err.Error())
 	}
-	a.Player = p
+	a.LocalPlayer = p
 	return nil
 }
 
 func (a *App) setupMPV() error {
 	a.Config.LocalPlayback.Volume = clamp(a.Config.LocalPlayback.Volume, 0, 100)
-	a.Player.SetVolume(a.Config.LocalPlayback.Volume)
+	a.LocalPlayer.SetVolume(a.Config.LocalPlayback.Volume)
 
-	devs, err := a.Player.ListAudioDevices()
+	devs, err := a.LocalPlayer.ListAudioDevices()
 	if err != nil {
 		return err
 	}
@@ -228,35 +229,41 @@ func (a *App) setupMPV() error {
 		// (e.g. a USB audio device that is currently unplugged)
 		desiredDevice = "auto"
 	}
-	a.Player.SetAudioDevice(desiredDevice)
+	a.LocalPlayer.SetAudioDevice(desiredDevice)
 
 	rgainOpts := []string{ReplayGainNone, ReplayGainAlbum, ReplayGainTrack, ReplayGainAuto}
 	if !sharedutil.SliceContains(rgainOpts, a.Config.ReplayGain.Mode) {
 		a.Config.ReplayGain.Mode = ReplayGainNone
 	}
-	mode := player.ReplayGainMode(a.Config.ReplayGain.Mode)
-	if a.Config.ReplayGain.Mode == ReplayGainAuto {
+	mode := player.ReplayGainNone
+	switch a.Config.ReplayGain.Mode {
+	case ReplayGainAlbum:
+		mode = player.ReplayGainAlbum
+	case ReplayGainTrack:
+		mode = player.ReplayGainTrack
+	case ReplayGainAuto:
 		mode = player.ReplayGainTrack
 	}
-	a.Player.SetReplayGainOptions(player.ReplayGainOptions{
+
+	a.LocalPlayer.SetReplayGainOptions(player.ReplayGainOptions{
 		Mode:            mode,
 		PreventClipping: a.Config.ReplayGain.PreventClipping,
 		PreampGain:      a.Config.ReplayGain.PreampGainDB,
 	})
-	a.Player.SetAudioExclusive(a.Config.LocalPlayback.AudioExclusive)
+	a.LocalPlayer.SetAudioExclusive(a.Config.LocalPlayback.AudioExclusive)
 
-	eq := &player.ISO15BandEqualizer{
+	eq := &mpv.ISO15BandEqualizer{
 		EQPreamp: a.Config.LocalPlayback.EqualizerPreamp,
 		Disabled: !a.Config.LocalPlayback.EqualizerEnabled,
 	}
 	copy(eq.BandGains[:], a.Config.LocalPlayback.GraphicEqualizerBands)
-	a.Player.SetEqualizer(eq)
+	a.LocalPlayer.SetEqualizer(eq)
 
 	return nil
 }
 
 func (a *App) setupMPRIS(mprisAppName string) {
-	a.MPRISHandler = NewMPRISHandler(mprisAppName, a.Player, a.PlaybackManager)
+	a.MPRISHandler = NewMPRISHandler(mprisAppName, a.PlaybackManager)
 	a.MPRISHandler.ArtURLLookup = a.ImageManager.GetCoverArtUrl
 	a.MPRISHandler.OnRaise = func() error { a.callOnReactivate(); return nil }
 	a.MPRISHandler.OnQuit = func() error {
@@ -293,10 +300,10 @@ func (a *App) DeleteServerCacheDir(serverID uuid.UUID) error {
 func (a *App) Shutdown() {
 	a.MPRISHandler.Shutdown()
 	a.PlaybackManager.DisableCallbacks()
-	a.Player.Stop() // will trigger scrobble check
-	a.Config.LocalPlayback.Volume = a.Player.GetVolume()
+	a.PlaybackManager.Stop() // will trigger scrobble check
+	a.Config.LocalPlayback.Volume = a.LocalPlayer.GetVolume()
 	a.cancel()
-	a.Player.Destroy()
+	a.LocalPlayer.Destroy()
 	a.Config.WriteConfigFile(a.configPath())
 	os.RemoveAll(configdir.LocalConfig(a.appName, sessionDir))
 }

backend/mediaprovider/mediaprovider.go

@@ -148,6 +148,25 @@ type SupportsRating interface {
 	SetRating(params RatingFavoriteParameters, rating int) error
 }
 
+type JukeboxProvider interface {
+	JukeboxStart() error
+	JukeboxStop() error
+	JukeboxSeek(idx, seconds int) error
+	JukeboxClear() error
+	JukeboxSet(trackID string) error
+	JukeboxAdd(trackID string) error
+	JukeboxRemove(idx int) error
+	JukeboxSetVolume(vol int) error
+	JukeboxGetStatus() (*JukeboxStatus, error)
+}
+
+type JukeboxStatus struct {
+	Volume          int
+	CurrentTrack    int
+	Playing         bool
+	PositionSeconds float64
+}
+
 func genresMatch(filterGenres, albumGenres []string) bool {
 	for _, g1 := range filterGenres {
 		for _, g2 := range albumGenres {

backend/mediaprovider/subsonic/jukebox.go

@@ -0,0 +1,67 @@
+package subsonic
+
+import (
+	"strconv"
+
+	"github.com/dweymouth/supersonic/backend/mediaprovider"
+)
+
+var _ mediaprovider.JukeboxProvider = (*subsonicMediaProvider)(nil)
+
+func (s *subsonicMediaProvider) JukeboxStart() error {
+	_, err := s.client.JukeboxControl("start", nil)
+	return err
+}
+
+func (s *subsonicMediaProvider) JukeboxStop() error {
+	_, err := s.client.JukeboxControl("stop", nil)
+	return err
+}
+
+func (s *subsonicMediaProvider) JukeboxClear() error {
+	_, err := s.client.JukeboxControl("clear", nil)
+	return err
+}
+
+func (s *subsonicMediaProvider) JukeboxSetVolume(vol int) error {
+	_, err := s.client.JukeboxControl("setGain",
+		map[string]string{"gain": strconv.Itoa(vol)})
+	return err
+}
+
+func (s *subsonicMediaProvider) JukeboxSeek(idx, seconds int) error {
+	_, err := s.client.JukeboxControl("skip",
+		map[string]string{"index": strconv.Itoa(idx), "offset": strconv.Itoa(seconds)})
+	return err
+}
+
+func (s *subsonicMediaProvider) JukeboxRemove(idx int) error {
+	_, err := s.client.JukeboxControl("remove",
+		map[string]string{"index": strconv.Itoa(idx)})
+	return err
+}
+
+func (s *subsonicMediaProvider) JukeboxSet(trackID string) error {
+	_, err := s.client.JukeboxControl("set",
+		map[string]string{"id": trackID})
+	return err
+}
+
+func (s *subsonicMediaProvider) JukeboxAdd(trackID string) error {
+	_, err := s.client.JukeboxControl("add",
+		map[string]string{"id": trackID})
+	return err
+}
+
+func (s *subsonicMediaProvider) JukeboxGetStatus() (*mediaprovider.JukeboxStatus, error) {
+	stat, err := s.client.JukeboxControl("status", nil)
+	if err != nil {
+		return nil, err
+	}
+	return &mediaprovider.JukeboxStatus{
+		Volume:          int(stat.Gain * 100),
+		CurrentTrack:    stat.CurrentIndex,
+		Playing:         stat.Playing,
+		PositionSeconds: float64(stat.Position),
+	}, nil
+}

backend/mpmedia_mac.go

@@ -16,13 +16,11 @@ import (
 )
 
 import (
-	"fmt"
 	"log"
 	"strings"
 	"unsafe"
 
 	"github.com/dweymouth/supersonic/backend/mediaprovider"
-	"github.com/dweymouth/supersonic/player"
 )
 
 // os_remote_command_callback is called by Objective-C when incoming OS media commands are received.
@@ -51,7 +49,6 @@ func os_remote_command_callback(command C.Command, value C.double) {
 
 // MPMediaHandler is the handler for MacOS media controls and system events.
 type MPMediaHandler struct {
-	player          *player.Player
 	playbackManager *PlaybackManager
 	artURLLookup    func(string) (string, error)
 }
@@ -62,9 +59,8 @@ var mpMediaEventRecipient *MPMediaHandler
 
 // NewMPMediaHandler creates a new MPMediaHandler instances and sets it as the current recipient
 // for incoming system events.
-func InitMPMediaHandler(player *player.Player, playbackManager *PlaybackManager, artURLLookup func(trackID string) (string, error)) error {
+func InitMPMediaHandler(playbackManager *PlaybackManager, artURLLookup func(trackID string) (string, error)) error {
 	mp := &MPMediaHandler{
-		player:          player,
 		playbackManager: playbackManager,
 		artURLLookup:    artURLLookup,
 	}
@@ -78,22 +74,22 @@ func InitMPMediaHandler(player *player.Player, playbackManager *PlaybackManager,
 		go mp.updateMetadata(track)
 	})
 
-	mp.player.OnStopped(func() {
+	mp.playbackManager.OnStopped(func() {
 		C.set_os_playback_state_stopped()
 	})
 
-	mp.player.OnSeek(func() {
-		C.update_os_now_playing_info_position(C.double(mp.player.GetStatus().TimePos))
+	mp.playbackManager.OnSeek(func() {
+		C.update_os_now_playing_info_position(C.double(mp.playbackManager.PlayerStatus().TimePos))
 	})
 
-	mp.player.OnPlaying(func() {
+	mp.playbackManager.OnPlaying(func() {
 		C.set_os_playback_state_playing()
-		C.update_os_now_playing_info_position(C.double(mp.player.GetStatus().TimePos))
+		C.update_os_now_playing_info_position(C.double(mp.playbackManager.PlayerStatus().TimePos))
 	})
 
-	mp.player.OnPaused(func() {
+	mp.playbackManager.OnPaused(func() {
 		C.set_os_playback_state_paused()
-		C.update_os_now_playing_info_position(C.double(mp.player.GetStatus().TimePos))
+		C.update_os_now_playing_info_position(C.double(mp.playbackManager.PlayerStatus().TimePos))
 	})
 
 	return nil
@@ -132,60 +128,56 @@ func (mp *MPMediaHandler) updateMetadata(track *mediaprovider.Track) {
 
 // MPMediaHandler instance received OS command 'pause'
 func (mp *MPMediaHandler) OnCommandPause() {
-	if mp == nil || mp.player == nil {
+	if mp == nil || mp.playbackManager == nil {
 		return
 	}
-	mp.player.Pause()
+	mp.playbackManager.Pause()
 }
 
 // MPMediaHandler instance received OS command 'play'
 func (mp *MPMediaHandler) OnCommandPlay() {
-	if mp == nil || mp.player == nil {
+	if mp == nil || mp.playbackManager == nil {
 		return
 	}
-	mp.player.Continue()
+	mp.playbackManager.Continue()
 }
 
 // MPMediaHandler instance received OS command 'stop'
 func (mp *MPMediaHandler) OnCommandStop() {
-	if mp == nil || mp.player == nil {
+	if mp == nil || mp.playbackManager == nil {
 		return
 	}
-	mp.player.Stop()
+	mp.playbackManager.Stop()
 }
 
 // MPMediaHandler instance received OS command 'toggle'
 func (mp *MPMediaHandler) OnCommandTogglePlayPause() {
-	if mp == nil || mp.player == nil {
+	if mp == nil || mp.playbackManager == nil {
 		return
 	}
-	if mp.player.GetStatus().State == player.Playing {
-		mp.OnCommandPause()
-	} else {
-		mp.OnCommandPlay()
-	}
+	mp.playbackManager.PlayPause()
 }
 
 // MPMediaHandler instance received OS command 'next track'
 func (mp *MPMediaHandler) OnCommandNextTrack() {
-	if mp == nil || mp.player == nil {
+	if mp == nil || mp.playbackManager == nil {
 		return
 	}
-	mp.player.SeekNext()
+	mp.playbackManager.SeekNext()
 }
 
 // MPMediaHandler instance received OS command 'previous track'
 func (mp *MPMediaHandler) OnCommandPreviousTrack() {
-	if mp == nil || mp.player == nil {
+	if mp == nil || mp.playbackManager == nil {
 		return
 	}
-	mp.player.SeekBackOrPrevious()
+	mp.playbackManager.SeekBackOrPrevious()
 }
 
 // MPMediaHandler instance received OS command to 'seek'
 func (mp *MPMediaHandler) OnCommandSeek(positionSeconds float64) {
-	if mp == nil || mp.player == nil {
+	if mp == nil || mp.playbackManager == nil {
 		return
 	}
-	mp.player.Seek(fmt.Sprintf("%0.2f", positionSeconds), player.SeekAbsolute)
+	mp.playbackManager.SeekSeconds(positionSeconds)
 }

backend/mpmedia_other.go

@@ -4,11 +4,9 @@ package backend
 
 import (
 	"errors"
-
-	"github.com/dweymouth/supersonic/player"
 )
 
-func InitMPMediaHandler(player *player.Player, playbackManager *PlaybackManager, artURLLookup func(trackID string) (string, error)) error {
+func InitMPMediaHandler(playbackManager *PlaybackManager, artURLLookup func(trackID string) (string, error)) error {
 	// MPMediaHandler only supports macOS.
 	return errors.New("unsupported platform")
 }

backend/mpris.go

@@ -3,7 +3,6 @@ package backend
 import (
 	"encoding/base32"
 	"errors"
-	"fmt"
 	"strconv"
 
 	"github.com/dweymouth/supersonic/backend/mediaprovider"
@@ -43,24 +42,23 @@ type MPRISHandler struct {
 	connErr      error
 	playerName   string
 	curTrackPath string // empty for no track
-	p            *player.Player
 	pm           *PlaybackManager
 	s            *server.Server
 	evt          *events.EventHandler
 }
 
-func NewMPRISHandler(playerName string, p *player.Player, pm *PlaybackManager) *MPRISHandler {
-	m := &MPRISHandler{playerName: playerName, p: p, pm: pm, connErr: errors.New("not started")}
+func NewMPRISHandler(playerName string, pm *PlaybackManager) *MPRISHandler {
+	m := &MPRISHandler{playerName: playerName, pm: pm, connErr: errors.New("not started")}
 	m.s = server.NewServer(playerName, m, m)
 	m.evt = events.NewEventHandler(m.s)
 
-	m.p.OnSeek(func() {
+	pm.OnSeek(func() {
 		if m.connErr == nil {
-			pos := secondsToMicroseconds(m.p.GetStatus().TimePos)
+			pos := secondsToMicroseconds(pm.PlayerStatus().TimePos)
 			m.evt.Player.OnSeek(pos)
 		}
 	})
-	m.pm.OnSongChange(func(tr, _ *mediaprovider.Track) {
+	pm.OnSongChange(func(tr, _ *mediaprovider.Track) {
 		if m.connErr == nil {
 			m.evt.Player.OnTitle()
 		}
@@ -70,7 +68,7 @@ func NewMPRISHandler(playerName string, p *player.Player, pm *PlaybackManager) *
 			m.curTrackPath = dbusTrackIDPrefix + encodeTrackId(tr.ID)
 		}
 	})
-	m.pm.OnVolumeChange(func(vol int) {
+	pm.OnVolumeChange(func(vol int) {
 		if m.connErr == nil {
 			m.evt.Player.OnVolume()
 		}
@@ -80,9 +78,9 @@ func NewMPRISHandler(playerName string, p *player.Player, pm *PlaybackManager) *
 			m.evt.Player.OnPlayPause()
 		}
 	}
-	m.p.OnStopped(emitPlayStatus)
-	m.p.OnPlaying(emitPlayStatus)
-	m.p.OnPaused(emitPlayStatus)
+	m.pm.OnStopped(emitPlayStatus)
+	m.pm.OnPlaying(emitPlayStatus)
+	m.pm.OnPaused(emitPlayStatus)
 
 	return m
 }
@@ -147,45 +145,47 @@ func (m *MPRISHandler) SupportedMimeTypes() ([]string, error) {
 // OrgMprisMediaPlayer2PlayerAdapter implementation
 
 func (m *MPRISHandler) Next() error {
-	return m.p.SeekNext()
+	return m.pm.SeekNext()
 }
 
 func (m *MPRISHandler) Previous() error {
-	return m.p.SeekBackOrPrevious()
+	return m.pm.SeekBackOrPrevious()
 }
 
 func (m *MPRISHandler) Pause() error {
-	if m.p.GetStatus().State == player.Playing {
-		return m.p.PlayPause()
+	if m.pm.PlayerStatus().State == player.Playing {
+		return m.pm.PlayPause()
 	}
 	return nil
 }
 
 func (m *MPRISHandler) PlayPause() error {
-	return m.p.PlayPause()
+	return m.pm.PlayPause()
 }
 
 func (m *MPRISHandler) Stop() error {
-	return m.p.Stop()
+	return m.pm.Stop()
 }
 
 func (m *MPRISHandler) Play() error {
-	switch m.p.GetStatus().State {
+	switch m.pm.PlayerStatus().State {
 	case player.Paused:
-		return m.p.PlayPause()
+		return m.pm.PlayPause()
 	case player.Stopped:
-		return m.p.PlayFromBeginning()
+		return m.pm.PlayFromBeginning()
 	}
 	return nil
 }
 
 func (m *MPRISHandler) Seek(offset types.Microseconds) error {
-	return m.p.Seek(fmt.Sprintf("%0.2f", microsecondsToSeconds(offset)), player.SeekRelative)
+	// MPRIS seek command is relative to current position
+	pos := m.pm.PlayerStatus().TimePos + microsecondsToSeconds(offset)
+	return m.pm.SeekSeconds(pos)
 }
 
 func (m *MPRISHandler) SetPosition(trackId string, position types.Microseconds) error {
 	if m.curTrackPath == trackId {
-		return m.p.Seek(fmt.Sprintf("%0.2f", microsecondsToSeconds(position)), player.SeekAbsolute)
+		return m.pm.SeekSeconds(microsecondsToSeconds(position))
 	}
 	return nil
 }
@@ -195,7 +195,7 @@ func (m *MPRISHandler) OpenUri(uri string) error {
 }
 
 func (m *MPRISHandler) PlaybackStatus() (types.PlaybackStatus, error) {
-	switch m.p.GetStatus().State {
+	switch m.pm.PlayerStatus().State {
 	case player.Playing:
 		return types.PlaybackStatusPlaying, nil
 	case player.Paused:
@@ -207,12 +207,12 @@ func (m *MPRISHandler) PlaybackStatus() (types.PlaybackStatus, error) {
 }
 
 func (m *MPRISHandler) LoopStatus() (types.LoopStatus, error) {
-	switch m.pm.LoopMode() {
-	case LoopModeAll:
+	switch m.pm.GetLoopMode() {
+	case LoopAll:
 		return types.LoopStatusPlaylist, nil
-	case LoopModeOne:
+	case LoopOne:
 		return types.LoopStatusTrack, nil
-	case LoopModeNone:
+	case LoopNone:
 		return types.LoopStatusNone, nil
 	}
 	return "", errors.New("unknown loop status")
@@ -221,13 +221,15 @@ func (m *MPRISHandler) LoopStatus() (types.LoopStatus, error) {
 func (m *MPRISHandler) SetLoopStatus(status types.LoopStatus) error {
 	switch status {
 	case types.LoopStatusPlaylist:
-		return m.pm.SetLoopMode(LoopModeAll)
+		m.pm.SetLoopMode(LoopAll)
 	case types.LoopStatusTrack:
-		return m.pm.SetLoopMode(LoopModeOne)
+		m.pm.SetLoopMode(LoopOne)
 	case types.LoopStatusNone:
-		return m.pm.SetLoopMode(LoopModeNone)
-	}
+		m.pm.SetLoopMode(LoopNone)
+	default:
 		return errors.New("unknown loop status")
+	}
+	return nil
 }
 
 func (m *MPRISHandler) Rate() (float64, error) {
@@ -243,7 +245,7 @@ func (m *MPRISHandler) Metadata() (types.Metadata, error) {
 	if m.curTrackPath != "" {
 		trackObjPath = m.curTrackPath
 	}
-	status := m.p.GetStatus()
+	status := m.pm.PlayerStatus()
 	var tr mediaprovider.Track
 	if np := m.pm.NowPlaying(); np != nil && status.State != player.Stopped {
 		tr = *np
@@ -271,7 +273,7 @@ func (m *MPRISHandler) Metadata() (types.Metadata, error) {
 }
 
 func (m *MPRISHandler) Volume() (float64, error) {
-	return float64(m.p.GetVolume()) / 100, nil
+	return float64(m.pm.Volume()) / 100, nil
 }
 
 func (m *MPRISHandler) SetVolume(v float64) error {
@@ -279,7 +281,7 @@ func (m *MPRISHandler) SetVolume(v float64) error {
 }
 
 func (m *MPRISHandler) Position() (int64, error) {
-	return int64(secondsToMicroseconds(m.p.GetStatus().TimePos)), nil
+	return int64(secondsToMicroseconds(m.pm.PlayerStatus().TimePos)), nil
 }
 
 func (m *MPRISHandler) MinimumRate() (float64, error) {
@@ -326,4 +328,3 @@ func encodeTrackId(id string) string {
 	data := []byte(id)
 	return base32.StdEncoding.WithPadding('0').EncodeToString(data)
 }
-

backend/playbackmanager.go

@@ -2,6 +2,7 @@ package backend
 
 import (
 	"context"
+	"errors"
 	"log"
 	"math/rand"
 	"time"
@@ -12,30 +13,29 @@ import (
 	"github.com/dweymouth/supersonic/sharedutil"
 )
 
-const (
-	ReplayGainNone  = string(player.ReplayGainNone)
-	ReplayGainAlbum = string(player.ReplayGainAlbum)
-	ReplayGainTrack = string(player.ReplayGainTrack)
+var (
+	ReplayGainNone  = player.ReplayGainNone.String()
+	ReplayGainAlbum = player.ReplayGainAlbum.String()
+	ReplayGainTrack = player.ReplayGainTrack.String()
 	ReplayGainAuto  = "Auto"
 )
 
+// The playback loop mode (LoopNone, LoopAll, LoopOne).
 type LoopMode int
 
 const (
-	LoopModeNone LoopMode = LoopMode(player.LoopNone)
-	LoopModeAll  LoopMode = LoopMode(player.LoopAll)
-	LoopModeOne  LoopMode = LoopMode(player.LoopOne)
+	LoopNone LoopMode = iota
+	LoopAll
+	LoopOne
 )
 
-// A high-level Subsonic-aware playback backend.
-// Manages loading tracks into the Player queue,
-// sending callbacks on play time updates and track changes.
+// A high-level MediaProvider-aware playback engine, serves as an
+// intermediary between the frontend and various Player backends.
 type PlaybackManager struct {
 	ctx           context.Context
 	cancelPollPos context.CancelFunc
-	pollingTick   *time.Ticker
 	sm            *ServerManager
-	player        *player.Player
+	player        player.BasePlayer
 
 	playTimeStopwatch   util.Stopwatch
 	curTrackTime        float64
@@ -43,7 +43,8 @@ type PlaybackManager struct {
 	callbacksDisabled   bool
 
 	playQueue     []*mediaprovider.Track
-	nowPlayingIdx int64
+	nowPlayingIdx int
+	loopMode      LoopMode
 
 	// to pass to onSongChange listeners; clear once listeners have been called
 	lastScrobbled *mediaprovider.Track
@@ -51,16 +52,22 @@ type PlaybackManager struct {
 	transcodeCfg  *TranscodingConfig
 	replayGainCfg ReplayGainConfig
 
+	// registered callbacks
 	onSongChange     []func(nowPlaying, justScrobbledIfAny *mediaprovider.Track)
 	onPlayTimeUpdate []func(float64, float64)
 	onLoopModeChange []func(LoopMode)
 	onVolumeChange   []func(int)
+	onSeek           []func()
+	onPaused         []func()
+	onStopped        []func()
+	onPlaying        []func()
+	onPlayerChange   []func()
 }
 
 func NewPlaybackManager(
 	ctx context.Context,
 	s *ServerManager,
-	p *player.Player,
+	p player.BasePlayer,
 	scrobbleCfg *ScrobbleConfig,
 	transcodeCfg *TranscodingConfig,
 ) *PlaybackManager {
@@ -72,38 +79,23 @@ func NewPlaybackManager(
 		player:        p,
 		scrobbleCfg:   scrobbleCfg,
 		transcodeCfg:  transcodeCfg,
+		nowPlayingIdx: -1,
 	}
-	p.OnTrackChange(func(tracknum int64) {
-		if tracknum >= int64(len(pm.playQueue)) {
-			return
-		}
-		pm.checkScrobble() // scrobble the previous song if needed
-		if pm.player.GetStatus().State == player.Playing {
-			pm.playTimeStopwatch.Start()
-		}
-		pm.nowPlayingIdx = tracknum
-		pm.curTrackTime = float64(pm.playQueue[pm.nowPlayingIdx].Duration)
-		pm.sendNowPlayingScrobble() // Must come before invokeOnChangeCallbacks b/c track may immediately be scrobbled
-		pm.invokeOnSongChangeCallbacks()
-		pm.doUpdateTimePos()
-	})
+	p.OnTrackChange(pm.handleOnTrackChange)
 	p.OnSeek(func() {
 		pm.doUpdateTimePos()
+		pm.invokeNoArgCallbacks(pm.onSeek)
 	})
-	p.OnStopped(func() {
-		pm.playTimeStopwatch.Stop()
-		pm.checkScrobble()
-		pm.stopPollTimePos()
-		pm.doUpdateTimePos()
-		pm.invokeOnSongChangeCallbacks()
-	})
+	p.OnStopped(pm.handleOnStopped)
 	p.OnPaused(func() {
 		pm.playTimeStopwatch.Stop()
 		pm.stopPollTimePos()
+		pm.invokeNoArgCallbacks(pm.onPaused)
 	})
 	p.OnPlaying(func() {
 		pm.playTimeStopwatch.Start()
 		pm.startPollTimePos()
+		pm.invokeNoArgCallbacks(pm.onPlaying)
 	})
 
 	s.OnLogout(func() {
@@ -113,6 +105,14 @@ func NewPlaybackManager(
 	return pm
 }
 
+func (p *PlaybackManager) CurrentPlayer() player.BasePlayer {
+	return p.player
+}
+
+func (p *PlaybackManager) OnPlayerChange(cb func()) {
+	p.onPlayerChange = append(p.onPlayerChange, cb)
+}
+
 func (p *PlaybackManager) IsSeeking() bool {
 	return p.player.IsSeeking()
 }
@@ -155,6 +155,26 @@ func (p *PlaybackManager) OnVolumeChange(cb func(int)) {
 	p.onVolumeChange = append(p.onVolumeChange, cb)
 }
 
+// Registers a callback that is notified whenever the player has been seeked.
+func (p *PlaybackManager) OnSeek(cb func()) {
+	p.onSeek = append(p.onSeek, cb)
+}
+
+// Registers a callback that is notified whenever the player has been paused.
+func (p *PlaybackManager) OnPaused(cb func()) {
+	p.onPaused = append(p.onPaused, cb)
+}
+
+// Registers a callback that is notified whenever the player is stopped.
+func (p *PlaybackManager) OnStopped(cb func()) {
+	p.onStopped = append(p.onStopped, cb)
+}
+
+// Registers a callback that is notified whenever the player begins playing.
+func (p *PlaybackManager) OnPlaying(cb func()) {
+	p.onPlaying = append(p.onPlaying, cb)
+}
+
 // Loads the specified album into the play queue.
 func (p *PlaybackManager) LoadAlbum(albumID string, appendToQueue bool, shuffle bool) error {
 	album, err := p.sm.Server.GetAlbum(albumID)
@@ -173,28 +193,29 @@ func (p *PlaybackManager) LoadPlaylist(playlistID string, appendToQueue bool, sh
 	return p.LoadTracks(playlist.Tracks, appendToQueue, shuffle)
 }
 
+// Load tracks into the play queue.
+// If replacing the current queue (!appendToQueue), playback will be stopped.
 func (p *PlaybackManager) LoadTracks(tracks []*mediaprovider.Track, appendToQueue, shuffle bool) error {
 	if !appendToQueue {
 		p.player.Stop()
-		p.nowPlayingIdx = 0
+		p.nowPlayingIdx = -1
 		p.playQueue = nil
 	}
 	nums := util.Range(len(tracks))
 	if shuffle {
 		rand.Shuffle(len(nums), func(i, j int) { nums[i], nums[j] = nums[j], nums[i] })
 	}
+	needToSetNext := appendToQueue && len(tracks) > 0 && p.nowPlayingIdx == len(p.playQueue)-1
 	for _, i := range nums {
-		url, err := p.sm.Server.GetStreamURL(tracks[i].ID, p.transcodeCfg.ForceRawFile)
-		if err != nil {
-			return err
-		}
-		p.player.AppendFile(url)
 		// ensure a deep copy of the track info so that we can maintain our own state
 		// (tracking play count increases, favorite, and rating) without messing up
 		// other views' track models
 		tr := *tracks[i]
 		p.playQueue = append(p.playQueue, &tr)
 	}
+	if needToSetNext {
+		p.setNextTrack(p.nowPlayingIdx + 1)
+	}
 	return nil
 }
 
@@ -205,10 +226,7 @@ func (p *PlaybackManager) PlayAlbum(albumID string, firstTrack int, shuffle bool
 	if p.replayGainCfg.Mode == ReplayGainAuto {
 		p.SetReplayGainMode(player.ReplayGainAlbum)
 	}
-	if firstTrack <= 0 {
-		return p.player.PlayFromBeginning()
-	}
-	return p.player.PlayTrackAt(firstTrack)
+	return p.PlayTrackAt(firstTrack)
 }
 
 func (p *PlaybackManager) PlayPlaylist(playlistID string, firstTrack int, shuffle bool) error {
@@ -218,10 +236,7 @@ func (p *PlaybackManager) PlayPlaylist(playlistID string, firstTrack int, shuffl
 	if p.replayGainCfg.Mode == ReplayGainAuto {
 		p.SetReplayGainMode(player.ReplayGainTrack)
 	}
-	if firstTrack <= 0 {
-		return p.player.PlayFromBeginning()
-	}
-	return p.player.PlayTrackAt(firstTrack)
+	return p.PlayTrackAt(firstTrack)
 }
 
 func (p *PlaybackManager) PlayTrack(trackID string) error {
@@ -237,28 +252,32 @@ func (p *PlaybackManager) PlayTrack(trackID string) error {
 }
 
 func (p *PlaybackManager) PlayFromBeginning() error {
-	return p.player.PlayFromBeginning()
+	return p.PlayTrackAt(0)
 }
 
 func (p *PlaybackManager) PlayTrackAt(idx int) error {
-	return p.player.PlayTrackAt(idx)
+	if idx < 0 || idx >= len(p.playQueue) {
+		return errors.New("track index out of range")
+	}
+	p.nowPlayingIdx = idx - 1
+	return p.setTrack(idx, false)
 }
 
 func (p *PlaybackManager) PlayRandomSongs(genreName string) {
-	if songs, err := p.sm.Server.GetRandomTracks(genreName, 100); err != nil {
-		log.Printf("error getting random songs: %s", err.Error())
-	} else {
-		p.LoadTracks(songs, false, false)
-		if p.replayGainCfg.Mode == ReplayGainAuto {
-			p.SetReplayGainMode(player.ReplayGainTrack)
-		}
-		p.PlayFromBeginning()
-	}
+	p.fetchAndPlayTracks(func() ([]*mediaprovider.Track, error) {
+		return p.sm.Server.GetRandomTracks(genreName, 100)
+	})
 }
 
 func (p *PlaybackManager) PlaySimilarSongs(id string) {
-	if songs, err := p.sm.Server.GetSimilarTracks(id, 100); err != nil {
-		log.Printf("error getting similar songs: %s", err.Error())
+	p.fetchAndPlayTracks(func() ([]*mediaprovider.Track, error) {
+		return p.sm.Server.GetSimilarTracks(id, 100)
+	})
+}
+
+func (p *PlaybackManager) fetchAndPlayTracks(fetchFn func() ([]*mediaprovider.Track, error)) {
+	if songs, err := fetchFn(); err != nil {
+		log.Printf("error fetching tracks: %s", err.Error())
 	} else {
 		p.LoadTracks(songs, false, false)
 		if p.replayGainCfg.Mode == ReplayGainAuto {
@@ -295,23 +314,23 @@ func (p *PlaybackManager) OnTrackRatingChanged(id string, rating int) {
 
 func (p *PlaybackManager) RemoveTracksFromQueue(trackIDs []string) {
 	newQueue := make([]*mediaprovider.Track, 0, len(p.playQueue)-len(trackIDs))
-	rmCount := 0
 	idSet := sharedutil.ToSet(trackIDs)
 	isPlayingTrackRemoved := false
+	isNextPlayingTrackremoved := false
+	nowPlaying := p.NowPlayingIndex()
+	newNowPlaying := nowPlaying
 	for i, tr := range p.playQueue {
 		if _, ok := idSet[tr.ID]; ok {
-			// removing this track
-			if i == p.NowPlayingIndex() {
+			if i < nowPlaying {
+				// if removing a track earlier than the currently playing one (if any),
+				// decrement new now playing index by one to account for new position in queue
+				newNowPlaying--
+			} else if i == nowPlaying {
 				isPlayingTrackRemoved = true
 				// If we are removing the currently playing track, we need to scrobble it
 				p.checkScrobble()
-			}
-			if err := p.player.RemoveTrackAt(i - rmCount); err == nil {
-				rmCount++
-			} else {
-				log.Printf("error removing track: %v", err.Error())
-				// did not remove this track
-				newQueue = append(newQueue, tr)
+			} else if nowPlaying >= 0 && i == nowPlaying+1 {
+				isNextPlayingTrackremoved = true
 			}
 		} else {
 			// not removing this track
@@ -319,28 +338,54 @@ func (p *PlaybackManager) RemoveTracksFromQueue(trackIDs []string) {
 		}
 	}
 	p.playQueue = newQueue
-	p.nowPlayingIdx = p.player.GetStatus().PlaylistPos
-	// fire on song change callbacks in case the playing track was removed
+	p.nowPlayingIdx = newNowPlaying
 	if isPlayingTrackRemoved {
-		p.invokeOnSongChangeCallbacks()
+		if newNowPlaying == len(newQueue) {
+			// we had been playing the last track, and removed it
+			p.Stop()
+		} else {
+			p.nowPlayingIdx -= 1 // will be incremented in newtrack callback from player
+			p.setTrack(newNowPlaying, false)
+		}
+		// setNextTrack and onSongChange callbacks will be handled
+		// when we receive new track event from player
+	} else if isNextPlayingTrackremoved {
+		if newNowPlaying < len(newQueue)-1 {
+			p.setNextTrack(p.nowPlayingIdx + 1)
+		} else {
+			// no next track to play
+			p.setNextTrack(-1)
+		}
 	}
 }
 
 // Stop playback and clear the play queue.
 func (p *PlaybackManager) StopAndClearPlayQueue() {
 	p.player.Stop()
-	p.player.ClearPlayQueue()
 	p.doUpdateTimePos()
 	p.playQueue = nil
+	p.nowPlayingIdx = -1
 }
 
 func (p *PlaybackManager) SetReplayGainOptions(config ReplayGainConfig) {
-	p.replayGainCfg = config
-	mode := player.ReplayGainMode(config.Mode)
-	if config.Mode == ReplayGainAuto {
-		mode = player.ReplayGainTrack
+	rGainPlayer, ok := p.player.(player.ReplayGainPlayer)
+	if !ok {
+		log.Println("Error: player doesn't support ReplayGain")
+		return
 	}
-	p.player.SetReplayGainOptions(player.ReplayGainOptions{
+
+	p.replayGainCfg = config
+	mode := player.ReplayGainNone
+	switch config.Mode {
+	case ReplayGainAuto:
+		mode = player.ReplayGainTrack
+	case ReplayGainTrack:
+		mode = player.ReplayGainTrack
+	case ReplayGainAlbum:
+		mode = player.ReplayGainAlbum
+	}
+
+	rGainPlayer.SetReplayGainOptions(player.ReplayGainOptions{
 		Mode:            mode,
 		PreventClipping: config.PreventClipping,
 		PreampGain:      config.PreampGainDB,
@@ -348,7 +393,12 @@ func (p *PlaybackManager) SetReplayGainOptions(config ReplayGainConfig) {
 }
 
 func (p *PlaybackManager) SetReplayGainMode(mode player.ReplayGainMode) {
-	p.player.SetReplayGainOptions(player.ReplayGainOptions{
+	rGainPlayer, ok := p.player.(player.ReplayGainPlayer)
+	if !ok {
+		log.Println("Error: player doesn't support ReplayGain")
+		return
+	}
+	rGainPlayer.SetReplayGainOptions(player.ReplayGainOptions{
 		PreventClipping: p.replayGainCfg.PreventClipping,
 		PreampGain:      p.replayGainCfg.PreampGainDB,
 		Mode:            mode,
@@ -357,32 +407,33 @@ func (p *PlaybackManager) SetReplayGainMode(mode player.ReplayGainMode) {
 
 // Changes the loop mode of the player to the next one.
 // Useful for toggling UI elements, to change modes without knowing the current player mode.
-func (p *PlaybackManager) SetNextLoopMode() error {
-	if err := p.player.SetNextLoopMode(); err != nil {
-		return err
-	}
+func (p *PlaybackManager) SetNextLoopMode() {
+	switch p.loopMode {
+	case LoopNone:
+		p.SetLoopMode(LoopAll)
+	case LoopAll:
+		p.SetLoopMode(LoopOne)
+	case LoopOne:
+		p.SetLoopMode(LoopNone)
 
-	for _, cb := range p.onLoopModeChange {
-		cb(LoopMode(p.player.GetLoopMode()))
 	}
-
-	return nil
 }
 
-func (p *PlaybackManager) SetLoopMode(loopMode LoopMode) error {
-	if err := p.player.SetLoopMode(player.LoopMode(loopMode)); err != nil {
-		return err
-	}
+func (p *PlaybackManager) SetLoopMode(loopMode LoopMode) {
+	p.loopMode = loopMode
+	p.setNextTrackBasedOnLoopMode(true)
 
 	for _, cb := range p.onLoopModeChange {
 		cb(loopMode)
 	}
-
-	return nil
 }
 
-func (p *PlaybackManager) LoopMode() LoopMode {
-	return LoopMode(p.player.GetLoopMode())
+func (p *PlaybackManager) GetLoopMode() LoopMode {
+	return p.loopMode
+}
+
+func (p *PlaybackManager) PlayerStatus() player.Status {
+	return p.player.GetStatus()
 }
 
 func (p *PlaybackManager) SetVolume(vol int) error {
@@ -400,6 +451,143 @@ func (p *PlaybackManager) Volume() int {
 	return p.player.GetVolume()
 }
 
+func (p *PlaybackManager) SeekNext() error {
+	if p.CurrentPlayer().GetStatus().State == player.Stopped {
+		return nil
+	}
+	return p.PlayTrackAt(p.nowPlayingIdx + 1)
+}
+
+func (p *PlaybackManager) SeekBackOrPrevious() error {
+	if p.nowPlayingIdx == 0 || p.player.GetStatus().TimePos > 3 {
+		return p.player.SeekSeconds(0)
+	}
+	return p.PlayTrackAt(p.nowPlayingIdx - 1)
+}
+
+// Seek to given absolute position in the current track by seconds.
+func (p *PlaybackManager) SeekSeconds(sec float64) error {
+	return p.player.SeekSeconds(sec)
+}
+
+// Seek to a fractional position in the current track [0..1]
+func (p *PlaybackManager) SeekFraction(fraction float64) error {
+	if fraction < 0 {
+		fraction = 0
+	} else if fraction > 1 {
+		fraction = 1
+	}
+	target := p.curTrackTime * fraction
+	return p.player.SeekSeconds(target)
+}
+
+func (p *PlaybackManager) Stop() error {
+	return p.player.Stop()
+}
+
+func (p *PlaybackManager) Pause() error {
+	return p.player.Pause()
+}
+
+func (p *PlaybackManager) Continue() error {
+	if p.player.GetStatus().State == player.Stopped {
+		return p.PlayFromBeginning()
+	}
+	return p.player.Continue()
+}
+
+func (p *PlaybackManager) PlayPause() error {
+	switch p.player.GetStatus().State {
+	case player.Playing:
+		return p.player.Pause()
+	case player.Paused:
+		return p.player.Continue()
+	case player.Stopped:
+		return p.PlayFromBeginning()
+	}
+	return errors.New("unreached - invalid player state")
+}
+
+func (p *PlaybackManager) handleOnTrackChange() {
+	p.checkScrobble() // scrobble the previous song if needed
+	if p.player.GetStatus().State == player.Playing {
+		p.playTimeStopwatch.Start()
+	}
+	if p.loopMode != LoopOne {
+		p.nowPlayingIdx++
+		if p.loopMode == LoopAll && p.nowPlayingIdx == len(p.playQueue) {
+			p.nowPlayingIdx = 0 // wrapped around
+		}
+	}
+	p.curTrackTime = float64(p.playQueue[p.nowPlayingIdx].Duration)
+	p.sendNowPlayingScrobble() // Must come before invokeOnChangeCallbacks b/c track may immediately be scrobbled
+	p.invokeOnSongChangeCallbacks()
+	p.doUpdateTimePos()
+	p.setNextTrackBasedOnLoopMode(false)
+}
+
+func (p *PlaybackManager) handleOnStopped() {
+	p.playTimeStopwatch.Stop()
+	p.checkScrobble()
+	p.stopPollTimePos()
+	p.doUpdateTimePos()
+	p.invokeOnSongChangeCallbacks()
+	p.invokeNoArgCallbacks(p.onStopped)
+	p.nowPlayingIdx = -1
+}
+
+func (p *PlaybackManager) setNextTrackBasedOnLoopMode(onLoopModeChange bool) {
+	switch p.loopMode {
+	case LoopNone:
+		if p.nowPlayingIdx < len(p.playQueue)-1 {
+			p.setNextTrack(p.nowPlayingIdx + 1)
+		} else if onLoopModeChange {
+			// prev was LoopOne - need to erase next track
+			p.setNextTrack(-1)
+		}
+	case LoopOne:
+		p.setNextTrack(p.nowPlayingIdx)
+	case LoopAll:
+		if p.nowPlayingIdx >= len(p.playQueue)-1 {
+			p.setNextTrack(0)
+		} else if !onLoopModeChange {
+			// if onloopmodechange, prev mode was LoopNone and next track is already set
+			p.setNextTrack(p.nowPlayingIdx + 1)
+		}
+	}
+}
+
+func (p *PlaybackManager) setTrack(idx int, next bool) error {
+	if urlP, ok := p.player.(player.URLPlayer); ok {
+		url := ""
+		if idx >= 0 {
+			var err error
+			url, err = p.sm.Server.GetStreamURL(p.playQueue[idx].ID, p.transcodeCfg.ForceRawFile)
+			if err != nil {
+				return err
+			}
+		}
+		if next {
+			return urlP.SetNextFile(url)
+		}
+		return urlP.PlayFile(url)
+	} else if trP, ok := p.player.(player.TrackPlayer); ok {
+		var track *mediaprovider.Track
+		if idx >= 0 {
+			track = p.playQueue[idx]
+		}
+		if next {
+			return trP.SetNextTrack(track)
+		}
+		return trP.PlayTrack(track)
+	}
+	panic("Unsupported player type")
+}
+
+func (p *PlaybackManager) setNextTrack(idx int) error {
+	return p.setTrack(idx, true)
+}
+
 // call BEFORE updating p.nowPlayingIdx
 func (p *PlaybackManager) checkScrobble() {
 	if !p.scrobbleCfg.Enabled || len(p.playQueue) == 0 || p.nowPlayingIdx < 0 {
@@ -450,26 +638,40 @@ func (p *PlaybackManager) invokeOnSongChangeCallbacks() {
 	p.lastScrobbled = nil
 }
 
+func (pm *PlaybackManager) invokeNoArgCallbacks(cbs []func()) {
+	if pm.callbacksDisabled {
+		return
+	}
+	for _, cb := range cbs {
+		cb()
+	}
+}
+
 func (p *PlaybackManager) startPollTimePos() {
 	ctx, cancel := context.WithCancel(p.ctx)
 	p.cancelPollPos = cancel
-	p.pollingTick = time.NewTicker(250 * time.Millisecond)
+	pollingTick := time.NewTicker(250 * time.Millisecond)
 
-	// TODO: fix occasional nil pointer dereference on app quit
 	go func() {
 		for {
 			select {
 			case <-ctx.Done():
-				p.pollingTick.Stop()
-				p.pollingTick = nil
+				pollingTick.Stop()
 				return
-			case <-p.pollingTick.C:
+			case <-pollingTick.C:
 				p.doUpdateTimePos()
 			}
 		}
 	}()
 }
 
+func (p *PlaybackManager) stopPollTimePos() {
+	if p.cancelPollPos != nil {
+		p.cancelPollPos()
+		p.cancelPollPos = nil
+	}
+}
+
 func (p *PlaybackManager) doUpdateTimePos() {
 	if p.callbacksDisabled {
 		return
@@ -482,13 +684,3 @@ func (p *PlaybackManager) doUpdateTimePos() {
 		cb(s.TimePos, s.Duration)
 	}
 }
-
-func (p *PlaybackManager) stopPollTimePos() {
-	if p.cancelPollPos != nil {
-		p.cancelPollPos()
-		p.cancelPollPos = nil
-	}
-	if p.pollingTick != nil {
-		p.pollingTick.Stop()
-	}
-}

go.mod

@@ -8,7 +8,7 @@ require (
 	github.com/deluan/sanitize v0.0.0-20230310221930-6e18967d9fc1
 	github.com/dweymouth/go-jellyfin v0.0.0-20231116161116-e800860bdacc
 	github.com/dweymouth/go-mpv v0.0.0-20230406003141-7f1858e503ee
-	github.com/dweymouth/go-subsonic v0.0.0-20231216234924-3f62122dc53a
+	github.com/dweymouth/go-subsonic v0.0.0-20231217175944-9b48c9ffc002
 	github.com/fsnotify/fsnotify v1.6.0
 	github.com/godbus/dbus/v5 v5.1.0
 	github.com/google/uuid v1.3.0

go.sum

@@ -75,8 +75,8 @@ github.com/dweymouth/go-jellyfin v0.0.0-20231116161116-e800860bdacc h1:wJy4U12Ys
 github.com/dweymouth/go-jellyfin v0.0.0-20231116161116-e800860bdacc/go.mod h1:BMwS4vdjEYf1gmjPGSKCzWP/I6YlI6fkefJ9nsjBjaU=
 github.com/dweymouth/go-mpv v0.0.0-20230406003141-7f1858e503ee h1:ZGyJ6wp7CAfT31BugypcF/TPKEy2RrGR9JFq1JOjOpY=
 github.com/dweymouth/go-mpv v0.0.0-20230406003141-7f1858e503ee/go.mod h1:Ov0ieN90M7i+0k3OxhA/g1dozGs+UcPHDsMKqPgRDk0=
-github.com/dweymouth/go-subsonic v0.0.0-20231216234924-3f62122dc53a h1:UJcwloSIzRpUOIwRE207JF2SHoTmOg7vJWzfQWpztSk=
-github.com/dweymouth/go-subsonic v0.0.0-20231216234924-3f62122dc53a/go.mod h1:OWtcumdQsan8uM6wmx6PqKhldaCthH10CQ+vb+94kzo=
+github.com/dweymouth/go-subsonic v0.0.0-20231217175944-9b48c9ffc002 h1:DhWQZJObkCUSFmHu/eEzHRqy0R33DcR266nPAvZJE34=
+github.com/dweymouth/go-subsonic v0.0.0-20231217175944-9b48c9ffc002/go.mod h1:OWtcumdQsan8uM6wmx6PqKhldaCthH10CQ+vb+94kzo=
 github.com/envoyproxy/go-control-plane v0.9.0/go.mod h1:YTl/9mNaCwkRvm6d1a2C3ymFceY/DCBVvsKhRF0iEA4=
 github.com/envoyproxy/go-control-plane v0.9.1-0.20191026205805-5f8ba28d4473/go.mod h1:YTl/9mNaCwkRvm6d1a2C3ymFceY/DCBVvsKhRF0iEA4=
 github.com/envoyproxy/go-control-plane v0.9.4/go.mod h1:6rpuAdCZL397s3pYoYcLgu1mIlRU8Am5FuJP05cCM98=

player/jukebox/jukeboxplayer.go

@@ -0,0 +1,132 @@
+package jukebox
+
+import (
+	"github.com/dweymouth/supersonic/backend/mediaprovider"
+	"github.com/dweymouth/supersonic/player"
+)
+
+const (
+	stopped = 0
+	playing = 1
+	paused  = 2
+)
+
+type JukeboxPlayer struct {
+	provider mediaprovider.JukeboxProvider
+
+	state     int // stopped, playing, paused
+	volume    int
+	seeking   bool
+	numTracks int
+
+	curTrack          int
+	curTrackDuration  float64
+	startTrackTime    float64
+	startedAtUnixSecs float64
+}
+
+func (j *JukeboxPlayer) SetVolume(vol int) error {
+	go func() {
+		if err := j.provider.JukeboxSetVolume(vol); err == nil {
+			j.volume = vol
+		}
+	}()
+	return nil
+}
+
+func (j *JukeboxPlayer) GetVolume() int {
+	return j.volume
+}
+
+func (j *JukeboxPlayer) PlayTrackAt(idx int) error {
+	go func() {
+		if err := j.provider.JukeboxSeek(idx, 0); err == nil {
+			j.curTrack = idx
+			j.Continue()
+		}
+	}()
+	return nil
+}
+
+func (j *JukeboxPlayer) Continue() error {
+	if j.state == playing {
+		return nil
+	}
+	go func() {
+		if err := j.provider.JukeboxStart(); err != nil {
+			return
+		}
+		j.state = playing
+	}()
+	return nil
+}
+
+func (j *JukeboxPlayer) Pause() error {
+	if j.state != playing {
+		return nil
+	}
+	go func() {
+		if err := j.provider.JukeboxStop(); err != nil {
+			return
+		}
+		j.state = paused
+	}()
+	return nil
+}
+
+func (j *JukeboxPlayer) Stop() error {
+	if j.state == stopped {
+		return nil
+	}
+	go func() {
+		if err := j.provider.JukeboxStop(); err != nil {
+			return
+		}
+		j.state = stopped
+	}()
+	return nil
+}
+
+func (j *JukeboxPlayer) SeekPrevious() error {
+	track := j.curTrack
+	if track > 0 {
+		track = j.curTrack - 1
+	}
+	return j.PlayTrackAt(track)
+}
+
+func (j *JukeboxPlayer) SeekNext() error {
+	track := j.curTrack
+	if track >= j.numTracks {
+		return nil
+	}
+	return j.PlayTrackAt(track + 1)
+}
+
+func (j *JukeboxPlayer) SeekSeconds(secs float64) error {
+	j.seeking = true
+	go func() {
+		j.provider.JukeboxSeek(j.curTrack, int(secs))
+		j.seeking = false
+	}()
+	return nil
+}
+
+func (j *JukeboxPlayer) IsSeeking() bool {
+	return j.seeking
+}
+
+func (j *JukeboxPlayer) GetStatus() player.Status {
+	state := player.Stopped
+	if j.state == playing {
+		state = player.Playing
+	} else if j.state == paused {
+		state = player.Paused
+	}
+
+	// TODO - the rest
+
+	return player.Status{
+		State: state,
+	}
+}

player/mpv/equalizer.go

@@ -1,4 +1,4 @@
-package player
+package mpv
 
 // Equalizer implementations based on the ffmpeg 'equalizer' filter
 

player/mpv/player.go

@@ -0,0 +1,513 @@
+package mpv
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"math"
+	"strconv"
+
+	"github.com/dweymouth/go-mpv"
+	"github.com/dweymouth/supersonic/player"
+)
+
+// Error returned by many Player functions if called before the player has not been initialized.
+var ErrUnitialized error = errors.New("mpv player uninitialized")
+
+// Information about a specific audio device.
+// Returned by ListAudioDevices.
+type AudioDevice struct {
+	// The name of the audio device.
+	// This is the string to pass to SetAudioDevice.
+	Name string
+
+	// The description of the audio device.
+	// This is the friendly string that should be used in UIs.
+	Description string
+}
+
+// Media information about the currently playing media.
+type MediaInfo struct {
+	// The sample format as string. This uses the same names as used in other places of mpv.
+	// NOTE: this is the format that the decoder outputs, NOT necessarily the format of the file.
+	Format string
+
+	// Audio samplerate.
+	Samplerate int
+
+	// The number of channels.
+	ChannelCount int
+
+	// The audio codec.
+	Codec string
+
+	// The average bit rate in bits per second.
+	Bitrate int
+}
+
+var _ player.URLPlayer = (*Player)(nil)
+
+// Player encapsulates the mpv instance and provides functions
+// to control it and to check its status.
+type Player struct {
+	mpv            *mpv.Mpv
+	initialized    bool
+	vol            int
+	replayGainOpts player.ReplayGainOptions
+	haveRGainOpts  bool
+	audioExclusive bool
+	status         player.Status
+	seeking        bool
+	curPlaylistPos int64
+	lenPlaylist    int64
+	prePausedState player.State
+	clientName     string
+	equalizer      Equalizer
+
+	bgCancel context.CancelFunc
+
+	// callbacks
+	onPaused      []func()
+	onStopped     []func()
+	onPlaying     []func()
+	onSeek        []func()
+	onTrackChange []func()
+}
+
+// Returns a new player.
+// Must call Init on the player before it is ready for playback.
+func New() *Player {
+	return NewWithClientName("")
+}
+
+// Same as New, but sets the application name that mpv
+// reports to the system audio API.
+func NewWithClientName(c string) *Player {
+	return &Player{
+		vol:        -1, // use 100 in Init
+		clientName: c,
+	}
+}
+
+// Initializes the Player and makes it ready for playback.
+// Most Player functions will return ErrUnitialized if called before Init.
+func (p *Player) Init(maxCacheMB int) error {
+	if !p.initialized {
+		m := mpv.Create()
+
+		m.SetOptionString("idle", "yes")
+		m.SetOptionString("video", "no")
+		m.SetOptionString("audio-display", "no")
+		m.SetOptionString("gapless-audio", "weak")
+		m.SetOptionString("prefetch-playlist", "yes")
+		m.SetOptionString("force-seekable", "yes")
+		m.SetOptionString("terminal", "no")
+
+		// limit in-memory cache size
+		m.SetOptionString("demuxer-max-bytes", fmt.Sprintf("%dMiB", maxCacheMB))
+
+		if p.vol < 0 {
+			p.vol = 100
+		}
+		m.SetOption("volume", mpv.FORMAT_INT64, p.vol)
+
+		p.SetAudioExclusive(p.audioExclusive)
+		if p.haveRGainOpts {
+			p.SetReplayGainOptions(p.replayGainOpts)
+		}
+
+		if p.clientName != "" {
+			m.SetOptionString("audio-client-name", p.clientName)
+		}
+
+		if err := m.Initialize(); err != nil {
+			return fmt.Errorf("error initializing mpv: %s", err.Error())
+		}
+		p.mpv = m
+	}
+	ctx, cancel := context.WithCancel(context.Background())
+	go p.eventHandler(ctx)
+	p.bgCancel = cancel
+	p.initialized = true
+	return nil
+}
+
+// Plays the specified file, clearing the previous play queue, if any.
+func (p *Player) PlayFile(url string) error {
+	if !p.initialized {
+		return ErrUnitialized
+	}
+	err := p.mpv.Command([]string{"loadfile", url, "replace"})
+	if err == nil {
+		p.setState(player.Playing)
+		p.lenPlaylist = 1
+	}
+	return err
+}
+
+// Stops playback and clears the play queue.
+func (p *Player) Stop() error {
+	if !p.initialized {
+		return ErrUnitialized
+	}
+	var err error
+	if p.status.State == player.Stopped {
+		err = p.mpv.Command([]string{"playlist-clear"})
+	} else {
+		if err = p.mpv.Command([]string{"stop"}); err == nil {
+			// if player was paused, stop command actually doesn't clear pause state
+			err = p.setPaused(false)
+		}
+	}
+	if err == nil {
+		p.lenPlaylist = 0
+		p.setState(player.Stopped)
+	}
+	return err
+}
+
+func (p *Player) SetNextFile(url string) error {
+	if p.lenPlaylist > p.curPlaylistPos+1 {
+		if err := p.mpv.Command([]string{"playlist-remove", strconv.Itoa(int(p.curPlaylistPos) + 1)}); err != nil {
+			return err
+		}
+		p.lenPlaylist--
+	}
+	if url == "" {
+		return nil
+	}
+
+	err := p.mpv.Command([]string{"loadfile", url, "append"})
+	if err == nil {
+		p.lenPlaylist++
+	}
+	return err
+}
+
+// Seeks within the currently playing track.
+// See MPV seek command documentation for more details.
+func (p *Player) SeekSeconds(secs float64) error {
+	if !p.initialized {
+		return ErrUnitialized
+	}
+	target := fmt.Sprintf("%0.1f", secs)
+	p.seeking = true
+	err := p.mpv.Command([]string{"seek", target, "absolute"})
+	return err
+}
+
+// Sets the volume of the player (0-100).
+// Unlike most Player functions, SetVolume can be called before Init,
+// to set the initial volume of the player on startup.
+func (p *Player) SetVolume(vol int) error {
+	if vol > 100 {
+		vol = 100
+	} else if vol < 0 {
+		vol = 0
+	}
+	if p.initialized {
+		err := p.mpv.SetProperty("volume", mpv.FORMAT_INT64, vol)
+		if err == nil {
+			p.vol = vol
+		}
+		return err
+	}
+	p.vol = vol
+	return nil
+}
+
+// Sets the ReplayGain options of the player.
+// Unlike most Player functions, SetReplayGainOptions can be called
+// before Init, to set the initial replaygain options of the player on startup.
+func (p *Player) SetReplayGainOptions(options player.ReplayGainOptions) error {
+	p.replayGainOpts = options
+	p.haveRGainOpts = true
+	mode := "no"
+	switch options.Mode {
+	case player.ReplayGainAlbum:
+		mode = "album"
+	case player.ReplayGainTrack:
+		mode = "track"
+	}
+
+	if p.initialized {
+		if err := p.mpv.SetPropertyString("replaygain", mode); err != nil {
+			return err
+		}
+		if err := p.mpv.SetProperty("replaygain-preamp", mpv.FORMAT_DOUBLE, options.PreampGain); err != nil {
+			return err
+		}
+		clip := "yes"
+		if options.PreventClipping {
+			clip = "no"
+		}
+		if err := p.mpv.SetPropertyString("replaygain-clip", clip); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// Sets the audio exclusive option of the player.
+// Unlike most Player functions, SetAudioExclusive can be called
+// before Init, to set the initial option of the player on startup.
+func (p *Player) SetAudioExclusive(tf bool) {
+	p.audioExclusive = tf
+	if p.initialized {
+		val := "no"
+		if tf {
+			val = "yes"
+		}
+		p.mpv.SetOptionString("audio-exclusive", val)
+	}
+}
+
+// Gets the current volume of the player.
+func (p *Player) GetVolume() int {
+	return p.vol
+}
+
+// sets paused status and ensures that audio exlusive is false while paused
+// (releases audio device to other players)
+func (p *Player) setPaused(paused bool) error {
+	if !paused && p.audioExclusive {
+		if err := p.mpv.SetOptionString("audio-exclusive", "yes"); err != nil {
+			return err
+		}
+	}
+	err := p.mpv.SetProperty("pause", mpv.FORMAT_FLAG, paused)
+	if err == nil && paused && p.audioExclusive {
+		err = p.mpv.SetOptionString("audio-exclusive", "no")
+	}
+	return err
+}
+
+// Pause playback and update the player state
+func (p *Player) Pause() error {
+	if p.status.State != player.Playing {
+		return nil
+	}
+	err := p.setPaused(true)
+	if err == nil {
+		p.prePausedState = p.status.State
+		p.setState(player.Paused)
+	}
+	return err
+}
+
+// Continue playback and update the player state
+func (p *Player) Continue() error {
+	if p.status.State == player.Paused {
+		err := p.setPaused(false)
+		if err == nil {
+			p.setState(p.prePausedState)
+		}
+		return err
+	}
+
+	return nil
+}
+
+// Get the current status of the player.
+func (p *Player) GetStatus() player.Status {
+	if !p.initialized {
+		return p.status
+	}
+
+	pos, _ := p.mpv.GetProperty("playback-time", mpv.FORMAT_DOUBLE)
+	dur, _ := p.mpv.GetProperty("duration", mpv.FORMAT_DOUBLE)
+	if pos != nil {
+		p.status.TimePos = pos.(float64)
+	}
+	if dur != nil {
+		p.status.Duration = dur.(float64)
+	}
+	return p.status
+}
+
+// List available audio devices.
+func (p *Player) ListAudioDevices() ([]AudioDevice, error) {
+	n, err := p.mpv.GetProperty("audio-device-list", mpv.FORMAT_NODE)
+	if err != nil {
+		return nil, err
+	}
+	nodeArr := n.(*mpv.Node).Data.([]*mpv.Node)
+
+	devices := make([]AudioDevice, len(nodeArr))
+	for i, node := range nodeArr {
+		dev := node.Data.(map[string]*mpv.Node)
+		name := dev["name"].Data.(string)
+		desc := dev["description"].Data.(string)
+		devices[i] = AudioDevice{Name: name, Description: desc}
+	}
+	return devices, nil
+}
+
+func (p *Player) SetAudioDevice(deviceName string) error {
+	return p.mpv.SetPropertyString("audio-device", deviceName)
+}
+
+func (p *Player) SetEqualizer(eq Equalizer) error {
+	p.equalizer = eq
+	if eq == nil || !eq.IsEnabled() {
+		return p.mpv.SetPropertyString("af", "")
+	}
+	af := ""
+	if math.Abs(eq.Preamp()) > 0.01 {
+		af = fmt.Sprintf("volume=volume=%0.1fdB", eq.Preamp())
+	}
+	eqAF := eq.Curve().String()
+	if af == "" {
+		af = eqAF
+	} else if eqAF != "" {
+		af = fmt.Sprintf("%s,%s", af, eqAF)
+	}
+	return p.mpv.SetPropertyString("af", af)
+}
+
+func (p *Player) Equalizer() Equalizer {
+	return p.equalizer
+}
+
+func (p *Player) GetMediaInfo() (MediaInfo, error) {
+	var info MediaInfo
+	n, err := p.mpv.GetProperty("audio-params", mpv.FORMAT_NODE)
+	if err != nil {
+		return info, err
+	}
+	nodeMap := n.(*mpv.Node).Data.(map[string]*mpv.Node)
+	info.Format = nodeMap["format"].Data.(string)
+	info.Samplerate = int(nodeMap["samplerate"].Data.(int64))
+	info.ChannelCount = int(nodeMap["channel-count"].Data.(int64))
+
+	br, err := p.mpv.GetProperty("audio-bitrate", mpv.FORMAT_INT64)
+	if err == nil {
+		info.Bitrate = int(br.(int64))
+	}
+	codec, err := p.mpv.GetProperty("track-list/0/codec", mpv.FORMAT_STRING)
+	if err == nil {
+		info.Codec = codec.(string)
+	}
+
+	return info, nil
+}
+
+func (p *Player) getInt64Property(propName string) (int64, error) {
+	playpos, err := p.mpv.GetProperty(propName, mpv.FORMAT_INT64)
+	if err != nil {
+		return -1, err
+	}
+	if playpos != nil {
+		return playpos.(int64), nil
+	}
+	return -1, errors.New("mpv did not report playlist pos")
+}
+
+// Returns true if a seek is currently in progress.
+func (p *Player) IsSeeking() bool {
+	return p.seeking && p.status.State == player.Playing
+}
+
+// Registers a callback which is invoked when the player transitions to the Paused state.
+func (p *Player) OnPaused(cb func()) {
+	p.onPaused = append(p.onPaused, cb)
+}
+
+// Registers a callback which is invoked when the player transitions to the Stopped state.
+func (p *Player) OnStopped(cb func()) {
+	p.onStopped = append(p.onStopped, cb)
+}
+
+// Registers a callback which is invoked when the player transitions to the Playing state.
+func (p *Player) OnPlaying(cb func()) {
+	p.onPlaying = append(p.onPlaying, cb)
+}
+
+// Registers a callback which is invoked whenever a seek event occurs.
+func (p *Player) OnSeek(cb func()) {
+	p.onSeek = append(p.onSeek, cb)
+}
+
+// Registers a callback which is invoked when the currently playing track changes,
+// or when playback begins at any time from the Stopped state.
+// Callback is invoked with the index of the currently playing track (zero-based).
+func (p *Player) OnTrackChange(cb func()) {
+	p.onTrackChange = append(p.onTrackChange, cb)
+}
+
+// Destroy the player.
+func (p *Player) Destroy() {
+	if p.bgCancel != nil {
+		p.bgCancel()
+	}
+	if p.initialized {
+		p.mpv.Command([]string{"stop"})
+		p.mpv.TerminateDestroy()
+		p.initialized = false
+	}
+}
+
+// sets the state and invokes callbacks, if triggered
+func (p *Player) setState(s player.State) {
+	switch {
+	case s == player.Playing && p.status.State != player.Playing:
+		defer func() {
+			for _, cb := range p.onPlaying {
+				cb()
+			}
+		}()
+	case s == player.Paused && p.status.State != player.Paused:
+		defer func() {
+			for _, cb := range p.onPaused {
+				cb()
+			}
+		}()
+	case s == player.Stopped && p.status.State != player.Stopped:
+		defer func() {
+			for _, cb := range p.onStopped {
+				cb()
+			}
+		}()
+	}
+	p.status.State = s
+}
+
+func (p *Player) eventHandler(ctx context.Context) {
+	for {
+		select {
+		case <-ctx.Done():
+			return
+		default:
+			e := p.mpv.WaitEvent(1 /*timeout seconds*/)
+			if e.Event_Id != mpv.EVENT_NONE {
+				//log.Printf("mpv event: %+v\n", e)
+			}
+			switch e.Event_Id {
+			case mpv.EVENT_PLAYBACK_RESTART:
+				if p.seeking {
+					p.seeking = false
+				}
+			case mpv.EVENT_SEEK:
+				for _, cb := range p.onSeek {
+					cb()
+				}
+			case mpv.EVENT_FILE_LOADED:
+				p.curPlaylistPos, _ = p.getInt64Property("playlist-pos")
+				if p.status.State == player.Paused {
+					// seek while paused switches to a new file
+					// mpv does not fire seek event in this case
+					for _, cb := range p.onSeek {
+						cb()
+					}
+				}
+				for _, cb := range p.onTrackChange {
+					cb()
+				}
+			case mpv.EVENT_IDLE:
+				p.status.Duration = 0
+				p.status.TimePos = 0
+				p.setState(player.Stopped)
+			}
+		}
+	}
+}

player/player.go

@@ -1,18 +1,43 @@
 package player
 
-import (
-	"context"
-	"errors"
-	"fmt"
-	"log"
-	"math"
-	"strconv"
+import "github.com/dweymouth/supersonic/backend/mediaprovider"
 
-	"github.com/dweymouth/go-mpv"
-)
+type URLPlayer interface {
+	BasePlayer
+	PlayFile(url string) error
+	SetNextFile(url string) error
+}
 
-// Error returned by many Player functions if called before the player has not been initialized.
-var ErrUnitialized error = errors.New("mpv player uninitialized")
+type TrackPlayer interface {
+	BasePlayer
+	PlayTrack(track *mediaprovider.Track) error
+	SetNextTrack(track *mediaprovider.Track) error
+}
+
+type BasePlayer interface {
+	Continue() error
+	Pause() error
+	Stop() error
+
+	SeekSeconds(secs float64) error
+	IsSeeking() bool
+
+	SetVolume(int) error
+	GetVolume() int
+
+	GetStatus() Status
+
+	// Event API
+	OnPaused(func())
+	OnStopped(func())
+	OnPlaying(func())
+	OnSeek(func())
+	OnTrackChange(func())
+}
+
+type ReplayGainPlayer interface {
+	SetReplayGainOptions(ReplayGainOptions) error
+}
 
 // The playback state (Stopped, Paused, or Playing).
 type State int
@@ -29,26 +54,14 @@ type Status struct {
 	State    State
 	TimePos  float64
 	Duration float64
-	PlaylistPos int64
 }
 
-// Argument to Seek function (SeekAbsolute, SeekRelative, SeekAbsolutePercent, SeekRelativePercent).
-type SeekMode int
+type ReplayGainMode int
 
 const (
-	SeekAbsolute SeekMode = iota
-	SeekRelative
-	SeekAbsolutePercent
-	SeekRelativePercent
-)
-
-// One of "no", "track", or "album"
-type ReplayGainMode string
-
-const (
-	ReplayGainNone  ReplayGainMode = "no"
-	ReplayGainTrack ReplayGainMode = "track"
-	ReplayGainAlbum ReplayGainMode = "album"
+	ReplayGainNone ReplayGainMode = iota
+	ReplayGainTrack
+	ReplayGainAlbum
 )
 
 // Replay Gain options (argument to SetReplayGainOptions).
@@ -59,673 +72,13 @@ type ReplayGainOptions struct {
 	// Fallback gain intentionally omitted
 }
 
-// The playback loop mode (LoopNone, LoopAll, LoopOne).
-type LoopMode int
-
-const (
-	LoopNone LoopMode = iota
-	LoopAll
-	LoopOne
-)
-
-// Information about a specific audio device.
-// Returned by ListAudioDevices.
-type AudioDevice struct {
-	// The name of the audio device.
-	// This is the string to pass to SetAudioDevice.
-	Name string
-
-	// The description of the audio device.
-	// This is the friendly string that should be used in UIs.
-	Description string
-}
-
-// Media information about the currently playing media.
-type MediaInfo struct {
-	// The sample format as string. This uses the same names as used in other places of mpv.
-	// NOTE: this is the format that the decoder outputs, NOT necessarily the format of the file.
-	Format string
-
-	// Audio samplerate.
-	Samplerate int
-
-	// The number of channels.
-	ChannelCount int
-
-	// The audio codec.
-	Codec string
-
-	// The average bit rate in bits per second.
-	Bitrate int
-}
-
-// Player encapsulates the mpv instance and provides functions
-// to control it and to check its status.
-type Player struct {
-	mpv            *mpv.Mpv
-	initialized    bool
-	vol            int
-	replayGainOpts ReplayGainOptions
-	haveRGainOpts  bool
-	audioExclusive bool
-	status         Status
-	loopMode       LoopMode
-	seeking        bool
-	curPlaylistPos int64
-	prePausedState State
-	clientName     string
-	equalizer      Equalizer
-
-	bgCancel context.CancelFunc
-
-	// callbacks
-	onPaused      []func()
-	onStopped     []func()
-	onPlaying     []func()
-	onSeek        []func()
-	onTrackChange []func(int64)
-}
-
-// Returns a new player.
-// Must call Init on the player before it is ready for playback.
-func New() *Player {
-	return NewWithClientName("")
-}
-
-// Same as New, but sets the application name that mpv
-// reports to the system audio API.
-func NewWithClientName(c string) *Player {
-	return &Player{
-		vol:        -1, // use 100 in Init
-		clientName: c,
-	}
-}
-
-// Initializes the Player and makes it ready for playback.
-// Most Player functions will return ErrUnitialized if called before Init.
-func (p *Player) Init(maxCacheMB int) error {
-	if !p.initialized {
-		m := mpv.Create()
-
-		m.SetOptionString("idle", "yes")
-		m.SetOptionString("video", "no")
-		m.SetOptionString("audio-display", "no")
-		m.SetOptionString("gapless-audio", "weak")
-		m.SetOptionString("prefetch-playlist", "yes")
-		m.SetOptionString("force-seekable", "yes")
-		m.SetOptionString("terminal", "no")
-
-		// limit in-memory cache size
-		m.SetOptionString("demuxer-max-bytes", fmt.Sprintf("%dMiB", maxCacheMB))
-
-		if p.vol < 0 {
-			p.vol = 100
-		}
-		m.SetOption("volume", mpv.FORMAT_INT64, p.vol)
-
-		p.SetAudioExclusive(p.audioExclusive)
-		if p.haveRGainOpts {
-			p.SetReplayGainOptions(p.replayGainOpts)
-		}
-
-		if p.clientName != "" {
-			m.SetOptionString("audio-client-name", p.clientName)
-		}
-
-		if err := m.Initialize(); err != nil {
-			return fmt.Errorf("error initializing mpv: %s", err.Error())
-		}
-		p.mpv = m
-	}
-	ctx, cancel := context.WithCancel(context.Background())
-	go p.eventHandler(ctx)
-	p.bgCancel = cancel
-	p.initialized = true
-	return nil
-}
-
-// Appends the given file to the play queue.
-// Note that the Player API does not provide methods to read
-// the play queue. Clients are expected to maintain their own play queue model.
-func (p *Player) AppendFile(url string) error {
-	log.Printf("Adding playback URL: %s", url)
-	if !p.initialized {
-		return ErrUnitialized
-	}
-	return p.mpv.Command([]string{"loadfile", url, "append"})
-}
-
-// Plays the specified file, clearing the previous play queue, if any.
-func (p *Player) PlayFile(url string) error {
-	log.Printf("Adding playback URL: %s", url)
-	if !p.initialized {
-		return ErrUnitialized
-	}
-	err := p.mpv.Command([]string{"loadfile", url, "replace"})
-	if err == nil {
-		p.setState(Playing)
-	}
-	return err
-}
-
-// Removes the item at the given index from the internal playqueue.
-func (p *Player) RemoveTrackAt(idx int) error {
-	if !p.initialized {
-		return ErrUnitialized
-	}
-	return p.mpv.Command([]string{"playlist-remove", strconv.Itoa(idx)})
-}
-
-// Stops playback and clears the play queue.
-func (p *Player) Stop() error {
-	if !p.initialized {
-		return ErrUnitialized
-	}
-	var err error
-	if p.status.State == Stopped {
-		err = p.mpv.Command([]string{"playlist-clear"})
-	} else {
-		if err = p.mpv.Command([]string{"stop"}); err == nil {
-			// if player was paused, stop command actually doesn't clear pause state
-			err = p.setPaused(false)
-		}
-	}
-	if err == nil {
-		p.setState(Stopped)
-	}
-	return err
-}
-
-// Clears the play queue, except for the currently playing file.
-func (p *Player) ClearPlayQueue() error {
-	if !p.initialized {
-		return ErrUnitialized
-	}
-	return p.mpv.Command([]string{"playlist-clear"})
-}
-
-// Seeks within the currently playing track.
-// See MPV seek command documentation for more details.
-func (p *Player) Seek(target string, mode SeekMode) error {
-	if !p.initialized {
-		return ErrUnitialized
-	}
-	p.seeking = true
-	err := p.mpv.Command([]string{"seek", target, mode.String()})
-	return err
-}
-
-// Seeks to the beginning of the current track if:
-//   - The current track is the first track in the play queue, or
-//   - The current time is more than 3 seconds past the beginning of the track.
-//
-// Else seeks to the beginning of the previous track.
-func (p *Player) SeekBackOrPrevious() error {
-	if !p.initialized {
-		return ErrUnitialized
-	}
-
-	if pos, err := p.getInt64Property("time-pos"); err == nil && pos > 3 {
-		return p.Seek("0", SeekAbsolutePercent)
-	}
-	if pos, err := p.getInt64Property("playlist-pos"); err == nil && pos == 0 {
-		return p.Seek("0", SeekAbsolutePercent)
-	}
-	return p.mpv.Command([]string{"playlist-prev"})
-}
-
-// Seeks to the next track in the play queue, if any.
-func (p *Player) SeekNext() error {
-	if !p.initialized {
-		return ErrUnitialized
-	}
-	return p.mpv.Command([]string{"playlist-next"})
-}
-
-// Sets the volume of the player (0-100).
-// Unlike most Player functions, SetVolume can be called before Init,
-// to set the initial volume of the player on startup.
-func (p *Player) SetVolume(vol int) error {
-	if vol > 100 {
-		vol = 100
-	} else if vol < 0 {
-		vol = 0
-	}
-	if p.initialized {
-		err := p.mpv.SetProperty("volume", mpv.FORMAT_INT64, vol)
-		if err == nil {
-			p.vol = vol
-		}
-		return err
-	}
-	p.vol = vol
-	return nil
-}
-
-// Sets the ReplayGain options of the player.
-// Unlike most Player functions, SetReplayGainOptions can be called
-// before Init, to set the initial replaygain options of the player on startup.
-func (p *Player) SetReplayGainOptions(options ReplayGainOptions) error {
-	p.replayGainOpts = options
-	p.haveRGainOpts = true
-	if p.initialized {
-		if err := p.mpv.SetPropertyString("replaygain", string(options.Mode)); err != nil {
-			return err
-		}
-		if err := p.mpv.SetProperty("replaygain-preamp", mpv.FORMAT_DOUBLE, options.PreampGain); err != nil {
-			return err
-		}
-		clip := "yes"
-		if options.PreventClipping {
-			clip = "no"
-		}
-		if err := p.mpv.SetPropertyString("replaygain-clip", clip); err != nil {
-			return err
-		}
-	}
-	return nil
-}
-
-// Sets the audio exclusive option of the player.
-// Unlike most Player functions, SetAudioExclusive can be called
-// before Init, to set the initial option of the player on startup.
-func (p *Player) SetAudioExclusive(tf bool) {
-	p.audioExclusive = tf
-	if p.initialized {
-		val := "no"
-		if tf {
-			val = "yes"
-		}
-		p.mpv.SetOptionString("audio-exclusive", val)
-	}
-}
-
-// Gets the current volume of the player.
-func (p *Player) GetVolume() int {
-	return p.vol
-}
-
-// sets paused status and ensures that audio exlusive is false while paused
-// (releases audio device to other players)
-func (p *Player) setPaused(paused bool) error {
-	if !paused && p.audioExclusive {
-		if err := p.mpv.SetOptionString("audio-exclusive", "yes"); err != nil {
-			return err
-		}
-	}
-	err := p.mpv.SetProperty("pause", mpv.FORMAT_FLAG, paused)
-	if err == nil && paused && p.audioExclusive {
-		err = p.mpv.SetOptionString("audio-exclusive", "no")
-	}
-	return err
-}
-
-// Start playback from the first track in the play queue.
-func (p *Player) PlayFromBeginning() error {
-	return p.PlayTrackAt(0)
-}
-
-// Start playback from the specified track index in the play queue.
-func (p *Player) PlayTrackAt(idx int) error {
-	// check if we have anything to play
-	if c, err := p.getInt64Property("playlist-count"); err == nil && c <= int64(idx) {
-		return nil
-	}
-	err := p.mpv.Command([]string{"playlist-play-index", strconv.Itoa(idx)})
-	if p.GetStatus().State == Paused {
-		err = p.setPaused(false)
-	}
-	if err == nil {
-		p.setState(Playing)
-	}
-	return err
-}
-
-// Begins playback if there is anything in the play queue and player is stopped or paused.
-// If player is playing, pauses playback.
-func (p *Player) PlayPause() error {
-	if !p.initialized {
-		return ErrUnitialized
-	}
-
-	switch p.status.State {
-	case Stopped:
-		// check if we have anything to play
-		if c, err := p.getInt64Property("playlist-count"); err == nil && c > 0 {
-			err := p.mpv.Command([]string{"playlist-play-index", "0"})
-			if err == nil {
-				p.setState(Playing)
-			}
-			return err
-		}
-		return nil
-	case Playing:
-		return p.Pause()
-	case Paused:
-		return p.Continue()
+func (r ReplayGainMode) String() string {
+	switch r {
+	case ReplayGainTrack:
+		return "track"
+	case ReplayGainAlbum:
+		return "album"
 	default:
-		return errors.New("Unknown player state")
-	}
-}
-
-// Pause playback and update the player state
-func (p *Player) Pause() error {
-	if p.status.State != Playing {
-		return nil
-	}
-	err := p.setPaused(true)
-	if err == nil {
-		p.prePausedState = p.status.State
-		p.setState(Paused)
-	}
-	return err
-}
-
-// Continue playback and update the player state
-func (p *Player) Continue() error {
-	if p.status.State == Paused {
-		err := p.setPaused(false)
-		if err == nil {
-			p.setState(p.prePausedState)
-		}
-		return err
-	} else if p.status.State == Stopped {
-		return p.PlayFromBeginning()
-	}
-
-	return nil
-}
-
-// Get the loop mode of the player.
-func (p *Player) GetLoopMode() LoopMode {
-	return p.loopMode
-}
-
-// Set the loop mode of the player.
-func (p *Player) SetLoopMode(mode LoopMode) error {
-	if !p.initialized {
-		return ErrUnitialized
-	}
-
-	// Return early if player is already in specified mode
-	if mode == p.loopMode {
-		return nil
-	}
-
-	switch mode {
-	case LoopNone:
-		if err := p.mpv.SetOptionString("loop-playlist", "no"); err != nil {
-			return err
-		}
-		if err := p.mpv.SetOptionString("loop-file", "no"); err != nil {
-			return err
-		}
-	case LoopAll:
-		if err := p.mpv.SetOptionString("loop-playlist", "inf"); err != nil {
-			return err
-		}
-		if err := p.mpv.SetOptionString("loop-file", "no"); err != nil {
-			return err
-		}
-	case LoopOne:
-		if err := p.mpv.SetOptionString("loop-playlist", "no"); err != nil {
-			return err
-		}
-		if err := p.mpv.SetOptionString("loop-file", "inf"); err != nil {
-			return err
-		}
-	}
-	p.loopMode = mode
-
-	return nil
-}
-
-// Change the loop mode of the player to the next one.
-// Useful for toggling UI elements, to change modes without knowing the current player mode.
-func (p *Player) SetNextLoopMode() error {
-	switch p.loopMode {
-	case LoopNone:
-		return p.SetLoopMode(LoopAll)
-	case LoopAll:
-		return p.SetLoopMode(LoopOne)
-	case LoopOne:
-		return p.SetLoopMode(LoopNone)
-	default:
-		return nil
-	}
-}
-
-// Get the current status of the player.
-func (p *Player) GetStatus() Status {
-	if !p.initialized {
-		return p.status
-	}
-
-	pos, _ := p.mpv.GetProperty("playback-time", mpv.FORMAT_DOUBLE)
-	dur, _ := p.mpv.GetProperty("duration", mpv.FORMAT_DOUBLE)
-	if pos != nil {
-		p.status.TimePos = pos.(float64)
-	}
-	if dur != nil {
-		p.status.Duration = dur.(float64)
-	}
-	if playpos, err := p.getInt64Property("playlist-pos"); err == nil {
-		p.status.PlaylistPos = playpos
-	}
-	return p.status
-}
-
-// List available audio devices.
-func (p *Player) ListAudioDevices() ([]AudioDevice, error) {
-	n, err := p.mpv.GetProperty("audio-device-list", mpv.FORMAT_NODE)
-	if err != nil {
-		return nil, err
-	}
-	nodeArr := n.(*mpv.Node).Data.([]*mpv.Node)
-
-	devices := make([]AudioDevice, len(nodeArr))
-	for i, node := range nodeArr {
-		dev := node.Data.(map[string]*mpv.Node)
-		name := dev["name"].Data.(string)
-		desc := dev["description"].Data.(string)
-		devices[i] = AudioDevice{Name: name, Description: desc}
-	}
-	return devices, nil
-}
-
-func (p *Player) SetAudioDevice(deviceName string) error {
-	return p.mpv.SetPropertyString("audio-device", deviceName)
-}
-
-func (p *Player) SetEqualizer(eq Equalizer) error {
-	p.equalizer = eq
-	if eq == nil || !eq.IsEnabled() {
-		return p.mpv.SetPropertyString("af", "")
-	}
-	af := ""
-	if math.Abs(eq.Preamp()) > 0.01 {
-		af = fmt.Sprintf("volume=volume=%0.1fdB", eq.Preamp())
-	}
-	eqAF := eq.Curve().String()
-	if af == "" {
-		af = eqAF
-	} else if eqAF != "" {
-		af = fmt.Sprintf("%s,%s", af, eqAF)
-	}
-	return p.mpv.SetPropertyString("af", af)
-}
-
-func (p *Player) Equalizer() Equalizer {
-	return p.equalizer
-}
-
-func (p *Player) GetMediaInfo() (MediaInfo, error) {
-	var info MediaInfo
-	n, err := p.mpv.GetProperty("audio-params", mpv.FORMAT_NODE)
-	if err != nil {
-		return info, err
-	}
-	nodeMap := n.(*mpv.Node).Data.(map[string]*mpv.Node)
-	info.Format = nodeMap["format"].Data.(string)
-	info.Samplerate = int(nodeMap["samplerate"].Data.(int64))
-	info.ChannelCount = int(nodeMap["channel-count"].Data.(int64))
-
-	br, err := p.mpv.GetProperty("audio-bitrate", mpv.FORMAT_INT64)
-	if err == nil {
-		info.Bitrate = int(br.(int64))
-	}
-	codec, err := p.mpv.GetProperty("track-list/0/codec", mpv.FORMAT_STRING)
-	if err == nil {
-		info.Codec = codec.(string)
-	}
-
-	return info, nil
-}
-
-func (p *Player) getInt64Property(propName string) (int64, error) {
-	playpos, err := p.mpv.GetProperty(propName, mpv.FORMAT_INT64)
-	if err != nil {
-		return -1, err
-	}
-	if playpos != nil {
-		return playpos.(int64), nil
-	}
-	return -1, errors.New("mpv did not report playlist pos")
-}
-
-// Returns true if a seek is currently in progress.
-func (p *Player) IsSeeking() bool {
-	return p.seeking && p.status.State == Playing
-}
-
-// Registers a callback which is invoked when the player transitions to the Paused state.
-func (p *Player) OnPaused(cb func()) {
-	p.onPaused = append(p.onPaused, cb)
-}
-
-// Registers a callback which is invoked when the player transitions to the Stopped state.
-func (p *Player) OnStopped(cb func()) {
-	p.onStopped = append(p.onStopped, cb)
-}
-
-// Registers a callback which is invoked when the player transitions to the Playing state.
-func (p *Player) OnPlaying(cb func()) {
-	p.onPlaying = append(p.onPlaying, cb)
-}
-
-// Registers a callback which is invoked whenever a seek event occurs.
-func (p *Player) OnSeek(cb func()) {
-	p.onSeek = append(p.onSeek, cb)
-}
-
-// Registers a callback which is invoked when the currently playing track changes,
-// or when playback begins at any time from the Stopped state.
-// Callback is invoked with the index of the currently playing track (zero-based).
-func (p *Player) OnTrackChange(cb func(int64)) {
-	p.onTrackChange = append(p.onTrackChange, cb)
-}
-
-// Destroy the player.
-func (p *Player) Destroy() {
-	if p.bgCancel != nil {
-		p.bgCancel()
-	}
-	if p.initialized {
-		p.mpv.Command([]string{"stop"})
-		p.mpv.TerminateDestroy()
-		p.initialized = false
-	}
-}
-
-// sets the state and invokes callbacks, if triggered
-func (p *Player) setState(s State) {
-	switch {
-	case s == Playing && p.status.State != Playing:
-		defer func() {
-			for _, cb := range p.onPlaying {
-				cb()
-			}
-		}()
-	case s == Paused && p.status.State != Paused:
-		defer func() {
-			for _, cb := range p.onPaused {
-				cb()
-			}
-		}()
-	case s == Stopped && p.status.State != Stopped:
-		defer func() {
-			for _, cb := range p.onStopped {
-				cb()
-			}
-		}()
-	}
-	p.status.State = s
-}
-
-func (p *Player) eventHandler(ctx context.Context) {
-	for {
-		select {
-		case <-ctx.Done():
-			return
-		default:
-			e := p.mpv.WaitEvent(1 /*timeout seconds*/)
-			if e.Event_Id != mpv.EVENT_NONE {
-				//log.Printf("mpv event: %+v\n", e)
-			}
-			switch e.Event_Id {
-			case mpv.EVENT_PLAYBACK_RESTART:
-				if p.seeking {
-					p.seeking = false
-				}
-			case mpv.EVENT_SEEK:
-				for _, cb := range p.onSeek {
-					cb()
-				}
-			case mpv.EVENT_FILE_LOADED:
-				if p.status.State == Paused {
-					// seek while paused switches to a new file
-					// mpv does not fire seek event in this case
-					for _, cb := range p.onSeek {
-						cb()
-					}
-				}
-				if pos, err := p.getInt64Property("playlist-pos"); err == nil {
-					p.curPlaylistPos = pos
-					for _, cb := range p.onTrackChange {
-						cb(pos)
-					}
-				}
-			case mpv.EVENT_IDLE:
-				p.status.Duration = 0
-				p.status.TimePos = 0
-				p.setState(Stopped)
-			}
-		}
-	}
-}
-
-func (s SeekMode) String() string {
-	switch s {
-	case SeekAbsolute:
-		return "absolute"
-	case SeekRelative:
-		return "relative"
-	case SeekAbsolutePercent:
-		return "absolute-percent"
-	case SeekRelativePercent:
-		return "relative-percent"
-	}
-	return "UNKNOWN_SEEK_MODE"
-}
-
-func (l LoopMode) String() string {
-	switch l {
-	case LoopNone:
 		return "no"
-	case LoopAll:
-		return "all"
-	case LoopOne:
-		return "one"
 	}
-	return "UNKNOWN_LOOP_MODE"
 }

sharedutil/sharedutil.go

@@ -78,10 +78,10 @@ func Reversed[T any](ts []T) []T {
 	return new
 }
 
-func ToSet[T comparable](ts []T) map[T]interface{} {
-	set := make(map[T]interface{}, len(ts))
+func ToSet[T comparable](ts []T) map[T]struct{} {
+	set := make(map[T]struct{}, len(ts))
 	for _, t := range ts {
-		set[t] = nil
+		set[t] = struct{}{}
 	}
 	return set
 }

ui/bottompanel.go

@@ -1,14 +1,12 @@
 package ui
 
 import (
-	"fmt"
 	"image"
 	"log"
 	"time"
 
 	"github.com/dweymouth/supersonic/backend"
 	"github.com/dweymouth/supersonic/backend/mediaprovider"
-	"github.com/dweymouth/supersonic/player"
 	"github.com/dweymouth/supersonic/ui/controller"
 	"github.com/dweymouth/supersonic/ui/layouts"
 	"github.com/dweymouth/supersonic/ui/widgets"
@@ -22,7 +20,6 @@ type BottomPanel struct {
 	widget.BaseWidget
 
 	ImageManager *backend.ImageManager
-	playbackManager *backend.PlaybackManager
 
 	NowPlaying  *widgets.NowPlayingCard
 	Controls    *widgets.PlayerControls
@@ -34,24 +31,24 @@ type BottomPanel struct {
 
 var _ fyne.Widget = (*BottomPanel)(nil)
 
-func NewBottomPanel(p *player.Player, pm *backend.PlaybackManager, contr *controller.Controller) *BottomPanel {
-	bp := &BottomPanel{playbackManager: pm}
+func NewBottomPanel(pm *backend.PlaybackManager, contr *controller.Controller) *BottomPanel {
+	bp := &BottomPanel{}
 	bp.ExtendBaseWidget(bp)
 
-	bp.playbackManager.OnSongChange(bp.onSongChange)
-	bp.playbackManager.OnPlayTimeUpdate(func(cur, total float64) {
-		if !bp.playbackManager.IsSeeking() {
+	pm.OnSongChange(bp.onSongChange)
+	pm.OnPlayTimeUpdate(func(cur, total float64) {
+		if !pm.IsSeeking() {
 			bp.Controls.UpdatePlayTime(cur, total)
 		}
 	})
 
-	p.OnPaused(func() {
+	pm.OnPaused(func() {
 		bp.Controls.SetPlaying(false)
 	})
-	p.OnPlaying(func() {
+	pm.OnPlaying(func() {
 		bp.Controls.SetPlaying(true)
 	})
-	p.OnStopped(func() {
+	pm.OnStopped(func() {
 		bp.Controls.SetPlaying(false)
 	})
 
@@ -65,45 +62,45 @@ func NewBottomPanel(p *player.Player, pm *backend.PlaybackManager, contr *contro
 		}
 	}
 	bp.NowPlaying.OnSetFavorite = func(fav bool) {
-		contr.SetTrackFavorites([]string{bp.playbackManager.NowPlaying().ID}, fav)
+		contr.SetTrackFavorites([]string{pm.NowPlaying().ID}, fav)
 	}
 	bp.NowPlaying.OnSetRating = func(rating int) {
-		contr.SetTrackRatings([]string{bp.playbackManager.NowPlaying().ID}, rating)
+		contr.SetTrackRatings([]string{pm.NowPlaying().ID}, rating)
 	}
 	bp.NowPlaying.OnAddToPlaylist = func() {
-		contr.DoAddTracksToPlaylistWorkflow([]string{bp.playbackManager.NowPlaying().ID})
+		contr.DoAddTracksToPlaylistWorkflow([]string{pm.NowPlaying().ID})
 	}
 	bp.NowPlaying.OnAlbumNameTapped = func() {
-		contr.NavigateTo(controller.AlbumRoute(bp.playbackManager.NowPlaying().AlbumID))
+		contr.NavigateTo(controller.AlbumRoute(pm.NowPlaying().AlbumID))
 	}
 	bp.NowPlaying.OnArtistNameTapped = func(artistID string) {
 		contr.NavigateTo(controller.ArtistRoute(artistID))
 	}
 	bp.NowPlaying.OnTrackNameTapped = func() {
-		contr.NavigateTo(controller.NowPlayingRoute(bp.playbackManager.NowPlaying().ID))
+		contr.NavigateTo(controller.NowPlayingRoute(pm.NowPlaying().ID))
 	}
 	bp.Controls = widgets.NewPlayerControls()
 	bp.Controls.OnPlayPause(func() {
-		p.PlayPause()
+		pm.PlayPause()
 	})
 	bp.Controls.OnSeekNext(func() {
-		p.SeekNext()
+		pm.SeekNext()
 	})
 	bp.Controls.OnSeekPrevious(func() {
-		p.SeekBackOrPrevious()
+		pm.SeekBackOrPrevious()
 	})
 	bp.Controls.OnSeek(func(f float64) {
-		p.Seek(fmt.Sprintf("%d", int(f*100)), player.SeekAbsolutePercent)
+		pm.SeekFraction(f)
 	})
 
-	bp.AuxControls = widgets.NewAuxControls(p.GetVolume())
+	bp.AuxControls = widgets.NewAuxControls(pm.Volume())
 	pm.OnLoopModeChange(bp.AuxControls.SetLoopMode)
 	pm.OnVolumeChange(bp.AuxControls.VolumeControl.SetVolume)
 	bp.AuxControls.VolumeControl.OnSetVolume = func(v int) {
-		_ = bp.playbackManager.SetVolume(v)
+		_ = pm.SetVolume(v)
 	}
 	bp.AuxControls.OnChangeLoopMode(func() {
-		bp.playbackManager.SetNextLoopMode()
+		pm.SetNextLoopMode()
 	})
 
 	bp.container = container.New(layouts.NewLeftMiddleRightLayout(500),

ui/browsing/nowplayingpage.go

@@ -8,6 +8,7 @@ import (
 	"github.com/dweymouth/supersonic/backend"
 	"github.com/dweymouth/supersonic/backend/mediaprovider"
 	"github.com/dweymouth/supersonic/player"
+	"github.com/dweymouth/supersonic/player/mpv"
 	"github.com/dweymouth/supersonic/sharedutil"
 	"github.com/dweymouth/supersonic/ui/controller"
 	"github.com/dweymouth/supersonic/ui/layouts"
@@ -41,7 +42,6 @@ type nowPlayingPageState struct {
 	pool    *util.WidgetPool
 	conf    *backend.NowPlayingPageConfig
 	pm      *backend.PlaybackManager
-	p       *player.Player
 	canRate bool
 }
 
@@ -51,17 +51,16 @@ func NewNowPlayingPage(
 	pool *util.WidgetPool,
 	conf *backend.NowPlayingPageConfig,
 	pm *backend.PlaybackManager,
-	p *player.Player, // TODO: once other player backends are supported (eg uPnP), refactor
 	canRate bool,
 ) *NowPlayingPage {
 	a := &NowPlayingPage{nowPlayingPageState: nowPlayingPageState{
-		contr: contr, pool: pool, conf: conf, pm: pm, p: p, canRate: canRate,
+		contr: contr, pool: pool, conf: conf, pm: pm, canRate: canRate,
 	}}
 	a.ExtendBaseWidget(a)
 
-	p.OnPaused(a.formatStatusLine)
-	p.OnPlaying(a.formatStatusLine)
-	p.OnStopped(a.formatStatusLine)
+	pm.OnPaused(a.formatStatusLine)
+	pm.OnPlaying(a.formatStatusLine)
+	pm.OnStopped(a.formatStatusLine)
 
 	if t := a.pool.Obtain(util.WidgetTypeTracklist); t != nil {
 		a.tracklist = t.(*widgets.Tracklist)
@@ -135,7 +134,8 @@ func (a *NowPlayingPage) OnPlayTimeUpdate(_, _ float64) {
 }
 
 func (a *NowPlayingPage) formatStatusLine() {
-	playerStats := a.p.GetStatus()
+	curPlayer := a.pm.CurrentPlayer()
+	playerStats := curPlayer.GetStatus()
 	lastStatus := a.statusLabel.Text
 	state := "Stopped"
 	switch playerStats.State {
@@ -160,12 +160,29 @@ func (a *NowPlayingPage) formatStatusLine() {
 	status := fmt.Sprintf("%s (%d/%d)%s", state, trackNum,
 		len(a.queue), statusSuffix)
 
-	if state == "Stopped" {
-		a.statusLabel.Text = fmt.Sprintf("%s | Total time: %s", status, util.SecondsToTimeString(a.totalTime))
-	} else {
-		audioInfo, err := a.p.GetMediaInfo()
+	mediaInfo := ""
+	if state != "Stopped" {
+		mediaInfo = a.formatMediaInfoStr(curPlayer)
+	}
+	if mediaInfo != "" {
+		mediaInfo = " · " + mediaInfo
+	}
+
+	a.statusLabel.Text = fmt.Sprintf("%s%s | Total time: %s", status, mediaInfo, util.SecondsToTimeString(a.totalTime))
+	if lastStatus != a.statusLabel.Text {
+		a.statusLabel.Refresh()
+	}
+}
+
+func (a *NowPlayingPage) formatMediaInfoStr(player player.BasePlayer) string {
+	mpv, ok := player.(*mpv.Player)
+	if !ok {
+		return ""
+	}
+	audioInfo, err := mpv.GetMediaInfo()
 	if err != nil {
 		log.Printf("error getting playback status: %s", err.Error())
+		return ""
 	}
 	codec := audioInfo.Codec
 	if len(codec) <= 4 && !strings.EqualFold(codec, "opus") {
@@ -174,16 +191,7 @@ func (a *NowPlayingPage) formatStatusLine() {
 
 	// Note: bit depth intentionally omitted since MPV reports the decoded bit depth
 	// i.e. 24 bit files get reported as 32 bit. Also b/c bit depth isn't meaningful for lossy.
-		a.statusLabel.Text = fmt.Sprintf("%s · %s %g kHz, %d kbps | Total time: %s",
-			status,
-			codec,
-			float64(audioInfo.Samplerate)/1000,
-			audioInfo.Bitrate/1000,
-			util.SecondsToTimeString(a.totalTime))
-	}
-	if lastStatus != a.statusLabel.Text {
-		a.statusLabel.Refresh()
-	}
+	return fmt.Sprintf("%s %g kHz, %d kbps", codec, float64(audioInfo.Samplerate)/1000, audioInfo.Bitrate/1000)
 }
 
 func (a *NowPlayingPage) Reload() {
@@ -216,5 +224,5 @@ func (a *NowPlayingPage) load(highlightedTrackID string) {
 }
 
 func (s *nowPlayingPageState) Restore() Page {
-	return NewNowPlayingPage("", s.contr, s.pool, s.conf, s.pm, s.p, s.canRate)
+	return NewNowPlayingPage("", s.contr, s.pool, s.conf, s.pm, s.canRate)
 }

ui/browsing/router.go

@@ -47,7 +47,7 @@ func (r Router) CreatePage(rte controller.Route) Page {
 		return NewGenresPage(r.Controller, r.App.ServerManager.Server)
 	case controller.NowPlaying:
 		_, canRate := r.App.ServerManager.Server.(mediaprovider.SupportsRating)
-		return NewNowPlayingPage(rte.Arg, r.Controller, r.widgetPool, &r.App.Config.NowPlayingPage, r.App.PlaybackManager, r.App.Player, canRate)
+		return NewNowPlayingPage(rte.Arg, r.Controller, r.widgetPool, &r.App.Config.NowPlayingPage, r.App.PlaybackManager, canRate)
 	case controller.Playlist:
 		return NewPlaylistPage(rte.Arg, &r.App.Config.PlaylistPage, r.widgetPool, r.Controller, r.App.ServerManager, r.App.PlaybackManager, r.App.ImageManager)
 	case controller.Playlists:

ui/controller/controller.go

@@ -13,6 +13,7 @@ import (
 	"github.com/dweymouth/supersonic/backend"
 	"github.com/dweymouth/supersonic/backend/mediaprovider"
 	"github.com/dweymouth/supersonic/player"
+	"github.com/dweymouth/supersonic/player/mpv"
 	"github.com/dweymouth/supersonic/sharedutil"
 	"github.com/dweymouth/supersonic/ui/dialogs"
 	"github.com/dweymouth/supersonic/ui/util"
@@ -471,31 +472,39 @@ func (c *Controller) ShowAboutDialog() {
 }
 
 func (c *Controller) ShowSettingsDialog(themeUpdateCallbk func(), themeFiles map[string]string) {
-	devs, err := c.App.Player.ListAudioDevices()
+	devs, err := c.App.LocalPlayer.ListAudioDevices()
 	if err != nil {
 		log.Printf("error listing audio devices: %v", err)
-		devs = []player.AudioDevice{{Name: "auto", Description: "Autoselect device"}}
+		devs = []mpv.AudioDevice{{Name: "auto", Description: "Autoselect device"}}
 	}
 
-	bands := c.App.Player.Equalizer().BandFrequencies()
-	dlg := dialogs.NewSettingsDialog(c.App.Config, devs, themeFiles, bands, c.App.ServerManager.Server.ClientDecidesScrobble(), c.MainWindow)
+	curPlayer := c.App.PlaybackManager.CurrentPlayer()
+	_, isReplayGainPlayer := curPlayer.(player.ReplayGainPlayer)
+	_, isEqualizerPlayer := curPlayer.(*mpv.Player)
+	isLocalPlayer := isEqualizerPlayer
+	bands := c.App.LocalPlayer.Equalizer().BandFrequencies()
+	dlg := dialogs.NewSettingsDialog(c.App.Config,
+		devs, themeFiles, bands,
+		c.App.ServerManager.Server.ClientDecidesScrobble(),
+		isLocalPlayer, isReplayGainPlayer, isEqualizerPlayer,
+		c.MainWindow)
 	dlg.OnReplayGainSettingsChanged = func() {
 		c.App.PlaybackManager.SetReplayGainOptions(c.App.Config.ReplayGain)
 	}
 	dlg.OnAudioExclusiveSettingChanged = func() {
-		c.App.Player.SetAudioExclusive(c.App.Config.LocalPlayback.AudioExclusive)
+		c.App.LocalPlayer.SetAudioExclusive(c.App.Config.LocalPlayback.AudioExclusive)
 	}
 	dlg.OnAudioDeviceSettingChanged = func() {
-		c.App.Player.SetAudioDevice(c.App.Config.LocalPlayback.AudioDeviceName)
+		c.App.LocalPlayer.SetAudioDevice(c.App.Config.LocalPlayback.AudioDeviceName)
 	}
 	dlg.OnThemeSettingChanged = themeUpdateCallbk
 	dlg.OnEqualizerSettingsChanged = func() {
 		// currently we only have one equalizer type
-		eq := c.App.Player.Equalizer().(*player.ISO15BandEqualizer)
+		eq := c.App.LocalPlayer.Equalizer().(*mpv.ISO15BandEqualizer)
 		eq.Disabled = !c.App.Config.LocalPlayback.EqualizerEnabled
 		eq.EQPreamp = c.App.Config.LocalPlayback.EqualizerPreamp
 		copy(eq.BandGains[:], c.App.Config.LocalPlayback.GraphicEqualizerBands)
-		c.App.Player.SetEqualizer(eq)
+		c.App.LocalPlayer.SetEqualizer(eq)
 	}
 	pop := widget.NewModalPopUp(dlg, c.MainWindow.Canvas())
 	dlg.OnDismiss = func() {

ui/dialogs/settingsdialog.go

@@ -10,7 +10,7 @@ import (
 	"unicode"
 
 	"github.com/dweymouth/supersonic/backend"
-	"github.com/dweymouth/supersonic/player"
+	"github.com/dweymouth/supersonic/player/mpv"
 	"github.com/dweymouth/supersonic/ui/layouts"
 	myTheme "github.com/dweymouth/supersonic/ui/theme"
 	"github.com/dweymouth/supersonic/ui/util"
@@ -37,7 +37,7 @@ type SettingsDialog struct {
 	OnEqualizerSettingsChanged     func()
 
 	config       *backend.Config
-	audioDevices []player.AudioDevice
+	audioDevices []mpv.AudioDevice
 	themeFiles   map[string]string // filename -> displayName
 	promptText   *widget.RichText
 
@@ -46,24 +46,39 @@ type SettingsDialog struct {
 	content fyne.CanvasObject
 }
 
-// TODO: having this depend on the player package for the AudioDevice type is kinda gross. Refactor.
+// TODO: having this depend on the mpv package for the AudioDevice type is kinda gross. Refactor.
 func NewSettingsDialog(
 	config *backend.Config,
-	audioDeviceList []player.AudioDevice,
+	audioDeviceList []mpv.AudioDevice,
 	themeFileList map[string]string,
 	equalizerBands []string,
 	clientDecidesScrobble bool,
+	isLocalPlayer bool,
+	isReplayGainPlayer bool,
+	isEqualizerPlayer bool,
 	window fyne.Window,
 ) *SettingsDialog {
 	s := &SettingsDialog{config: config, audioDevices: audioDeviceList, themeFiles: themeFileList, clientDecidesScrobble: clientDecidesScrobble}
 	s.ExtendBaseWidget(s)
 
-	tabs := container.NewAppTabs(
+	// TODO: Once Fyne supports disableable sliders, it's probably a nicer UX
+	// to create the equalizer tab but disable it if we are not using an equalizer player
+	var tabs *container.AppTabs
+	if isEqualizerPlayer {
+		tabs = container.NewAppTabs(
 			s.createGeneralTab(),
-		s.createPlaybackTab(),
+			s.createPlaybackTab(isLocalPlayer, isReplayGainPlayer),
 			s.createEqualizerTab(equalizerBands),
 			s.createExperimentalTab(window),
 		)
+	} else {
+		tabs = container.NewAppTabs(
+			s.createGeneralTab(),
+			s.createPlaybackTab(isLocalPlayer, isReplayGainPlayer),
+			s.createExperimentalTab(window),
+		)
+	}
+
 	tabs.SelectIndex(s.getActiveTabNumFromConfig())
 	// workaround issue where inactivated tabs don't fully update when theme setting is changed
 	tabs.OnSelected = func(ti *container.TabItem) {
@@ -249,7 +264,7 @@ func (s *SettingsDialog) createGeneralTab() *container.TabItem {
 	))
 }
 
-func (s *SettingsDialog) createPlaybackTab() *container.TabItem {
+func (s *SettingsDialog) createPlaybackTab(isLocalPlayer, isReplayGainPlayer bool) *container.TabItem {
 	disableTranscode := widget.NewCheckWithData("Disable server transcoding", binding.BindBool(&s.config.Transcoding.ForceRawFile))
 	deviceList := make([]string, len(s.audioDevices))
 	var selIndex int
@@ -328,6 +343,16 @@ func (s *SettingsDialog) createPlaybackTab() *container.TabItem {
 	})
 	audioExclusive.Checked = s.config.LocalPlayback.AudioExclusive
 
+	if !isLocalPlayer {
+		deviceSelect.Disable()
+		audioExclusive.Disable()
+	}
+	if !isReplayGainPlayer {
+		replayGainSelect.Disable()
+		preventClipping.Disable()
+		preampGain.Disable()
+	}
+
 	return container.NewTabItem("Playback", container.NewVBox(
 		container.NewHBox(disableTranscode),
 		container.New(&layouts.MaxPadLayout{PadTop: 5},

ui/mainwindow.go

@@ -79,7 +79,7 @@ func NewMainWindow(fyneApp fyne.App, appName, displayAppName, appVersion string,
 	m.Controller.ReloadFunc = m.BrowsingPane.Reload
 	m.Controller.CurPageFunc = m.BrowsingPane.CurrentPage
 
-	m.BottomPanel = NewBottomPanel(app.Player, app.PlaybackManager, m.Controller)
+	m.BottomPanel = NewBottomPanel(app.PlaybackManager, m.Controller)
 	m.BottomPanel.ImageManager = app.ImageManager
 	m.container = container.NewBorder(nil, m.BottomPanel, nil, nil, m.BrowsingPane)
 	m.Window.SetContent(m.container)
@@ -162,13 +162,13 @@ func (m *MainWindow) SetupSystemTrayMenu(appName string, fyneApp fyne.App) {
 	if desk, ok := fyneApp.(desktop.App); ok {
 		menu := fyne.NewMenu(appName,
 			fyne.NewMenuItem("Play/Pause", func() {
-				_ = m.App.Player.PlayPause()
+				_ = m.App.PlaybackManager.PlayPause()
 			}),
 			fyne.NewMenuItem("Previous", func() {
-				_ = m.App.Player.SeekBackOrPrevious()
+				_ = m.App.PlaybackManager.SeekBackOrPrevious()
 			}),
 			fyne.NewMenuItem("Next", func() {
-				_ = m.App.Player.SeekNext()
+				_ = m.App.PlaybackManager.SeekNext()
 			}),
 			fyne.NewMenuItemSeparator(),
 			fyne.NewMenuItem("Volume +10%", func() {
@@ -298,7 +298,7 @@ func (m *MainWindow) addShortcuts() {
 		case fyne.KeyEscape:
 			m.Controller.CloseEscapablePopUp()
 		case fyne.KeySpace:
-			m.App.Player.PlayPause()
+			m.App.PlaybackManager.PlayPause()
 		}
 	})
 }

ui/widgets/auxcontrols.go

@@ -69,13 +69,13 @@ func (a *AuxControls) OnChangeLoopMode(f func()) {
 
 func (a *AuxControls) SetLoopMode(mode backend.LoopMode) {
 	switch mode {
-	case backend.LoopModeAll:
+	case backend.LoopAll:
 		a.loop.Importance = widget.HighImportance
 		a.loop.Icon = myTheme.RepeatIcon
-	case backend.LoopModeOne:
+	case backend.LoopOne:
 		a.loop.Importance = widget.HighImportance
 		a.loop.Icon = myTheme.RepeatOneIcon
-	case backend.LoopModeNone:
+	case backend.LoopNone:
 		a.loop.Importance = widget.MediumImportance
 		a.loop.Icon = myTheme.RepeatIcon
 	}