wip player

backend/player/player.go

@@ -4,19 +4,26 @@ import (
 	"context"
 	"fmt"
 	"os"
+	"reflect"
 	"time"
 
 	"github.com/gopxl/beep"
+	"github.com/gopxl/beep/effects"
+	"github.com/gopxl/beep/generators"
 	"github.com/gopxl/beep/mp3"
 	"github.com/gopxl/beep/speaker"
 )
 
 type Player struct {
-	ctx        context.Context
-	state      PlayerState
-	streamer   beep.Streamer
-	format     beep.Format
-	sampleRate beep.SampleRate
+	ctx          context.Context
+	state        PlayerState
+	currentFile  os.File
+	format       beep.Format
+	baseStreamer beep.Streamer
+	resampled    beep.Streamer
+	control      beep.Ctrl
+	volume       effects.Volume
+	queue        []string
 }
 
 type PlayerState int
@@ -27,48 +34,134 @@ const (
 	Stopped
 )
 
+const testQueue = []string{
+	"test_data/music_library_test/gnomed.mp3",
+	"test_data/music_library_test/01 Some Chords.mp3",
+	"test_data/music_library_test/03 anything.mp3",
+}
+
 func NewPlayer() (*Player, error) {
 	return &Player{
-		// TODO: variable speaker sample rates
-		sampleRate: beep.SampleRate(44100),
+		state:        Stopped,
+		baseStreamer: generatorsilence(-1),
+		// Default sample rate
+		// TODO: read this from config
+		fileFormat: beep.Format{},
+		queue:      testQueue,
 	}, nil
 }
 
-func (p *Player) Init(ctx context.Context) {
+func (p *Player) Init(ctx context.Context) error {
 	p.ctx = ctx
 	p.state = Stopped
+	p.streamer = generators.Silence(-1)
 
-	speaker.Init(p.sampleRate, p.sampleRate.N(time.Second/10))
-}
-
-func (p *Player) ChangeState(desiredState PlayerState) error {
-	return nil
-}
-
-func (p *Player) Play(filePath string) error {
-	f, err := os.Open(filePath)
-	if err != nil {
-		return fmt.Errorf("failed to open file %w", err)
-	}
-
-	streamer, format, err := mp3.Decode(f)
-	if err != nil {
-		return fmt.Errorf("failed to decode mp3 %w", err)
-	}
-	defer streamer.Close()
-
-	// initialize the speaker with the sample rate from the file
-	err = speaker.Init(format.SampleRate, format.SampleRate.N(time.Second/10))
+	// Initialize speaker
+	// TODO: allow user to change buffer size and speaker sample rate
+	err := speaker.Init(p.speakerSampleRate, p.speakerSampleRate.N(time.Second/10))
 	if err != nil {
 		return fmt.Errorf("failed to initialize speaker %w", err)
 	}
 
+	return nil
+}
+
+// TODO: proper state management extracted to function
+func (p *Player) changeState(desiredState PlayerState) error {
+	return nil
+}
+
+// reads a file and creates a streamer resampled to match the speaker
+func (p *Player) CreateStreamerFromFile(filePath string) (beep.Streamer, error) {
+	f, err := os.Open(filePath)
+	if err != nil {
+		return nil, fmt.Errorf("failed to open file %w", err)
+	}
+
+	streamer, format, err := mp3.Decode(f)
+	p.fileFormat = format
+	if err != nil {
+		return nil, fmt.Errorf("failed to decode mp3 %w", err)
+	}
+
+	// resample file stream to match speaker
+	// TODO: variable resample quality
+	resampled := beep.Resample(4, p.fileFormat.SampleRate, p.speakerSampleRate, streamer)
+	// wrap in ctrl streamer to allow play/pause
+	ctrl := &beep.Ctrl{Streamer: resampled}
+	// wrap in volume streamer
+	volume := &effects.Volume{
+		Streamer: ctrl,
+		Base:     2,
+		Volume:   0,
+		Silent:   false,
+	}
+
+	return volume, nil
+}
+
+func (p *Player) Play(streamer beep.Streamer) error {
+	p.streamer = streamer
+	p.state = Playing
 	// hangs until song finishes playing
 	done := make(chan bool)
-	speaker.Play(beep.Seq(streamer, beep.Callback(func() {
+	speaker.Play(beep.Seq(p.streamer, beep.Callback(func() {
+		p.state = Paused //called when streamer finishes
 		done <- true
 	})))
 
 	<-done
 	return nil
 }
+
+// TODO: reduce dupilcation in pause/resume functions
+func (p *Player) Pause() error {
+	ctrl := &beep.Ctrl{}
+	// checking if current streamer is a ctrl type, if not, wrap it in one
+	if (reflect.TypeOf(p.streamer) != reflect.TypeOf(beep.Ctrl{})) {
+		ctrl = &beep.Ctrl{Streamer: p.streamer}
+	}
+	speaker.Lock()
+	ctrl.Paused = true
+	speaker.Unlock()
+	return nil
+}
+
+// TODO: reduce dupilcation in pause/resume functions
+func (p *Player) Resume() error {
+	ctrl := &beep.Ctrl{}
+	// checking if current streamer is a ctrl type, if not, wrap it in one
+	if (reflect.TypeOf(p.streamer) != reflect.TypeOf(beep.Ctrl{})) {
+		ctrl = &beep.Ctrl{Streamer: p.streamer}
+	}
+	speaker.Lock()
+	ctrl.Paused = false
+	speaker.Unlock()
+	return nil
+}
+
+//Paraprasing info from the beep docs here:
+/*
+To INCREASE volume by 1 means to multiply the signal by Base.
+Volume = 0 means unchanged volume.
+Positive Volume value means increasing volume
+Negative Volume value means decreasing volume
+*/
+// TODO: implement max/ min volume values
+func (p *Player) SetVolume() error {
+	volume := &effects.Volume{
+		Streamer: p.streamer,
+		Base:     2,
+		Volume:   0,
+		Silent:   false,
+	}
+	p.Play(volume)
+	return nil
+}
+
+func (p *Player) MuteToggle() error {
+
+	p.streamer.Silent = !p.Streamer.
+		p.Play(volume)
+	return nil
+}