Refactor pt. 1: move MPV player to own package and extract some types

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
+	Player          *mpv.Player
 	UpdateChecker   UpdateChecker
 	MPRISHandler    *MPRISHandler
 
@@ -194,7 +195,7 @@ 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 {
@@ -234,10 +235,16 @@ func (a *App) setupMPV() error {
 	if !sharedutil.SliceContains(rgainOpts, a.Config.ReplayGain.Mode) {
 		a.Config.ReplayGain.Mode = ReplayGainNone
 	}
-	mode := player.ReplayGainMode(a.Config.ReplayGain.Mode)
+	mode := player.ReplayGainNone
-	if a.Config.ReplayGain.Mode == ReplayGainAuto {
+	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{
 		Mode:            mode,
 		PreventClipping: a.Config.ReplayGain.PreventClipping,
@@ -245,7 +252,7 @@ func (a *App) setupMPV() error {
 	})
 	a.Player.SetAudioExclusive(a.Config.LocalPlayback.AudioExclusive)
 
-	eq := &player.ISO15BandEqualizer{
+	eq := &mpv.ISO15BandEqualizer{
 		EQPreamp: a.Config.LocalPlayback.EqualizerPreamp,
 		Disabled: !a.Config.LocalPlayback.EqualizerEnabled,
 	}

backend/mpmedia_mac.go

@@ -23,6 +23,7 @@ import (
 
 	"github.com/dweymouth/supersonic/backend/mediaprovider"
 	"github.com/dweymouth/supersonic/player"
+	"github.com/dweymouth/supersonic/player/mpv"
 )
 
 // os_remote_command_callback is called by Objective-C when incoming OS media commands are received.
@@ -51,7 +52,7 @@ 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
+	player          *mpv.Player
 	playbackManager *PlaybackManager
 	artURLLookup    func(string) (string, error)
 }
@@ -62,7 +63,7 @@ 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(player *mpv.Player, playbackManager *PlaybackManager, artURLLookup func(trackID string) (string, error)) error {
 	mp := &MPMediaHandler{
 		player:          player,
 		playbackManager: playbackManager,
@@ -187,5 +188,5 @@ func (mp *MPMediaHandler) OnCommandSeek(positionSeconds float64) {
 	if mp == nil || mp.player == nil {
 		return
 	}
-	mp.player.Seek(fmt.Sprintf("%0.2f", positionSeconds), player.SeekAbsolute)
+	mp.player.Seek(fmt.Sprintf("%0.2f", positionSeconds), mpv.SeekAbsolute)
 }

backend/mpris.go

@@ -8,6 +8,7 @@ import (
 
 	"github.com/dweymouth/supersonic/backend/mediaprovider"
 	"github.com/dweymouth/supersonic/player"
+	"github.com/dweymouth/supersonic/player/mpv"
 	"github.com/godbus/dbus/v5"
 	"github.com/quarckster/go-mpris-server/pkg/events"
 	"github.com/quarckster/go-mpris-server/pkg/server"
@@ -43,13 +44,13 @@ type MPRISHandler struct {
 	connErr      error
 	playerName   string
 	curTrackPath string // empty for no track
-	p            *player.Player
+	p            *mpv.Player
 	pm           *PlaybackManager
 	s            *server.Server
 	evt          *events.EventHandler
 }
 
-func NewMPRISHandler(playerName string, p *player.Player, pm *PlaybackManager) *MPRISHandler {
+func NewMPRISHandler(playerName string, p *mpv.Player, pm *PlaybackManager) *MPRISHandler {
 	m := &MPRISHandler{playerName: playerName, p: p, pm: pm, connErr: errors.New("not started")}
 	m.s = server.NewServer(playerName, m, m)
 	m.evt = events.NewEventHandler(m.s)
@@ -180,12 +181,12 @@ func (m *MPRISHandler) Play() error {
 }
 
 func (m *MPRISHandler) Seek(offset types.Microseconds) error {
-	return m.p.Seek(fmt.Sprintf("%0.2f", microsecondsToSeconds(offset)), player.SeekRelative)
+	return m.p.Seek(fmt.Sprintf("%0.2f", microsecondsToSeconds(offset)), mpv.SeekRelative)
 }
 
 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.p.Seek(fmt.Sprintf("%0.2f", microsecondsToSeconds(position)), mpv.SeekAbsolute)
 	}
 	return nil
 }
@@ -326,4 +327,3 @@ func encodeTrackId(id string) string {
 	data := []byte(id)
 	return base32.StdEncoding.WithPadding('0').EncodeToString(data)
 }
-

backend/playbackmanager.go

@@ -8,13 +8,14 @@ import (
 	"github.com/dweymouth/supersonic/backend/mediaprovider"
 	"github.com/dweymouth/supersonic/backend/util"
 	"github.com/dweymouth/supersonic/player"
+	"github.com/dweymouth/supersonic/player/mpv"
 	"github.com/dweymouth/supersonic/sharedutil"
 )
 
-const (
+var (
-	ReplayGainNone  = string(player.ReplayGainNone)
+	ReplayGainNone  = player.ReplayGainNone.String()
-	ReplayGainAlbum = string(player.ReplayGainAlbum)
+	ReplayGainAlbum = player.ReplayGainAlbum.String()
-	ReplayGainTrack = string(player.ReplayGainTrack)
+	ReplayGainTrack = player.ReplayGainTrack.String()
 	ReplayGainAuto  = "Auto"
 )
 
@@ -34,7 +35,7 @@ type PlaybackManager struct {
 	cancelPollPos context.CancelFunc
 	pollingTick   *time.Ticker
 	sm            *ServerManager
-	player        *player.Player
+	player        *mpv.Player
 
 	playTimeStopwatch   util.Stopwatch
 	curTrackTime        float64
@@ -59,7 +60,7 @@ type PlaybackManager struct {
 func NewPlaybackManager(
 	ctx context.Context,
 	s *ServerManager,
-	p *player.Player,
+	p *mpv.Player,
 	scrobbleCfg *ScrobbleConfig,
 	transcodeCfg *TranscodingConfig,
 ) *PlaybackManager {
@@ -335,7 +336,16 @@ func (p *PlaybackManager) StopAndClearPlayQueue() {
 
 func (p *PlaybackManager) SetReplayGainOptions(config ReplayGainConfig) {
 	p.replayGainCfg = config
-	mode := player.ReplayGainMode(config.Mode)
+	mode := player.ReplayGainNone
+	switch config.Mode {
+	case ReplayGainAuto:
+		mode = player.ReplayGainTrack
+	case ReplayGainTrack:
+		mode = player.ReplayGainTrack
+	case ReplayGainAlbum:
+		mode = player.ReplayGainAlbum
+	}
+
 	if config.Mode == ReplayGainAuto {
 		mode = player.ReplayGainTrack
 	}

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 +1,693 @@
+package mpv
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"log"
+	"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")
+
+// Argument to Seek function (SeekAbsolute, SeekRelative, SeekAbsolutePercent, SeekRelativePercent).
+type SeekMode 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"
+)
+
+// 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 player.ReplayGainOptions
+	haveRGainOpts  bool
+	audioExclusive bool
+	status         player.Status
+	loopMode       player.LoopMode
+	seeking        bool
+	curPlaylistPos int64
+	prePausedState player.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(player.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 == 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.setState(player.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 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
+}
+
+// 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 == player.Paused {
+		err = p.setPaused(false)
+	}
+	if err == nil {
+		p.setState(player.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 player.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(player.Playing)
+			}
+			return err
+		}
+		return nil
+	case player.Playing:
+		return p.Pause()
+	case player.Paused:
+		return p.Continue()
+	default:
+		return errors.New("Unknown player state")
+	}
+}
+
+// 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
+	} else if p.status.State == player.Stopped {
+		return p.PlayFromBeginning()
+	}
+
+	return nil
+}
+
+// Get the loop mode of the player.
+func (p *Player) GetLoopMode() player.LoopMode {
+	return p.loopMode
+}
+
+// Set the loop mode of the player.
+func (p *Player) SetLoopMode(mode player.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 player.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 player.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 player.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 player.LoopNone:
+		return p.SetLoopMode(player.LoopAll)
+	case player.LoopAll:
+		return p.SetLoopMode(player.LoopOne)
+	case player.LoopOne:
+		return p.SetLoopMode(player.LoopNone)
+	default:
+		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)
+	}
+	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 == 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(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 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:
+				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()
+					}
+				}
+				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(player.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"
+}

player/player.go

@@ -1,19 +1,5 @@
 package player
 
-import (
-	"context"
-	"errors"
-	"fmt"
-	"log"
-	"math"
-	"strconv"
-
-	"github.com/dweymouth/go-mpv"
-)
-
-// Error returned by many Player functions if called before the player has not been initialized.
-var ErrUnitialized error = errors.New("mpv player uninitialized")
-
 // The playback state (Stopped, Paused, or Playing).
 type State int
 
@@ -32,23 +18,21 @@ type Status struct {
 	PlaylistPos int64
 }
 
-// Argument to Seek function (SeekAbsolute, SeekRelative, SeekAbsolutePercent, SeekRelativePercent).
+// The playback loop mode (LoopNone, LoopAll, LoopOne).
-type SeekMode int
+type LoopMode int
 
 const (
-	SeekAbsolute SeekMode = iota
+	LoopNone LoopMode = iota
-	SeekRelative
+	LoopAll
-	SeekAbsolutePercent
+	LoopOne
-	SeekRelativePercent
 )
 
-// One of "no", "track", or "album"
+type ReplayGainMode int
-type ReplayGainMode string
 
 const (
-	ReplayGainNone  ReplayGainMode = "no"
+	ReplayGainNone ReplayGainMode = iota
-	ReplayGainTrack ReplayGainMode = "track"
+	ReplayGainTrack
-	ReplayGainAlbum ReplayGainMode = "album"
+	ReplayGainAlbum
 )
 
 // Replay Gain options (argument to SetReplayGainOptions).
@@ -59,665 +43,17 @@ type ReplayGainOptions struct {
 	// Fallback gain intentionally omitted
 }
 
-// The playback loop mode (LoopNone, LoopAll, LoopOne).
+func (r ReplayGainMode) String() string {
-type LoopMode int
+	switch r {
-
+	case ReplayGainTrack:
-const (
+		return "track"
-	LoopNone LoopMode = iota
+	case ReplayGainAlbum:
-	LoopAll
+		return "album"
-	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()
 	default:
-		return errors.New("Unknown player state")
+		return "no"
 	}
 }
 
-// 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:

ui/bottompanel.go

@@ -8,7 +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/ui/controller"
 	"github.com/dweymouth/supersonic/ui/layouts"
 	"github.com/dweymouth/supersonic/ui/widgets"
@@ -34,7 +34,7 @@ type BottomPanel struct {
 
 var _ fyne.Widget = (*BottomPanel)(nil)
 
-func NewBottomPanel(p *player.Player, pm *backend.PlaybackManager, contr *controller.Controller) *BottomPanel {
+func NewBottomPanel(p *mpv.Player, pm *backend.PlaybackManager, contr *controller.Controller) *BottomPanel {
 	bp := &BottomPanel{playbackManager: pm}
 	bp.ExtendBaseWidget(bp)
 
@@ -93,7 +93,7 @@ func NewBottomPanel(p *player.Player, pm *backend.PlaybackManager, contr *contro
 		p.SeekBackOrPrevious()
 	})
 	bp.Controls.OnSeek(func(f float64) {
-		p.Seek(fmt.Sprintf("%d", int(f*100)), player.SeekAbsolutePercent)
+		p.Seek(fmt.Sprintf("%d", int(f*100)), mpv.SeekAbsolutePercent)
 	})
 
 	bp.AuxControls = widgets.NewAuxControls(p.GetVolume())

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 +42,7 @@ type nowPlayingPageState struct {
 	pool    *util.WidgetPool
 	conf    *backend.NowPlayingPageConfig
 	pm      *backend.PlaybackManager
-	p       *player.Player
+	p       *mpv.Player
 	canRate bool
 }
 
@@ -51,7 +52,7 @@ func NewNowPlayingPage(
 	pool *util.WidgetPool,
 	conf *backend.NowPlayingPageConfig,
 	pm *backend.PlaybackManager,
-	p *player.Player, // TODO: once other player backends are supported (eg uPnP), refactor
+	p *mpv.Player, // TODO: once other player backends are supported (eg uPnP), refactor
 	canRate bool,
 ) *NowPlayingPage {
 	a := &NowPlayingPage{nowPlayingPageState: nowPlayingPageState{

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"
@@ -474,7 +475,7 @@ func (c *Controller) ShowSettingsDialog(themeUpdateCallbk func(), themeFiles map
 	devs, err := c.App.Player.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()
@@ -491,7 +492,7 @@ func (c *Controller) ShowSettingsDialog(themeUpdateCallbk func(), themeFiles map
 	dlg.OnThemeSettingChanged = themeUpdateCallbk
 	dlg.OnEqualizerSettingsChanged = func() {
 		// currently we only have one equalizer type
-		eq := c.App.Player.Equalizer().(*player.ISO15BandEqualizer)
+		eq := c.App.Player.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)

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
 
@@ -49,7 +49,7 @@ type SettingsDialog struct {
 // TODO: having this depend on the player 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,