subsonic-tui/internal/playback/controller.go

package playback

import (
	"io"
	"sync"
	"time"

	"github.com/delucks/go-subsonic"
	"github.com/gopxl/beep"
	"github.com/gopxl/beep/mp3"
	"github.com/gopxl/beep/speaker"
)

type Controller struct {
	stream          beep.StreamSeekCloser
	song            *subsonic.Child
	songElapsedFunc func(elapsed time.Duration)
	format          *beep.Format
	closeChan       chan bool
	songEndedFunc   func(song *subsonic.Child)
	isPlaying       bool
	ctrl            *beep.Ctrl
	tickerRunning   bool
	controllerLock  *sync.Mutex
}

func NewController() *Controller {
	controller := &Controller{
		closeChan:      make(chan bool),
		controllerLock: &sync.Mutex{},
	}
	return controller
}

func (c *Controller) Playing() bool {
	return c.isPlaying
}

func (c *Controller) SetSongElapsedFunc(f func(elapsed time.Duration)) {
	c.songElapsedFunc = f
}

func (c *Controller) SetSongEndedFunc(f func(song *subsonic.Child)) {
	c.songEndedFunc = f
}

func (c *Controller) Close() error {
	if c.tickerRunning {
		c.closeChan <- true
	}
	if c.stream != nil {
		c.Stop()
		speaker.Close()
	}
	return nil
}

func (c *Controller) TogglePlayPause() {
	if c.ctrl == nil {
		if c.stream != nil {
			c.ctrl.Streamer = c.stream
			c.ctrl.Paused = false
			return
		}
		return
	}
	c.ctrl.Paused = !c.ctrl.Paused
}

func (c *Controller) Stop() {
	if c.ctrl == nil {
		return
	}
	go func() {
		c.controllerLock.Lock()
		speaker.Clear()
		c.ctrl.Paused = true
		c.isPlaying = false
		c.ctrl = nil
		c.stream = nil
		c.song = nil
		c.songElapsedFunc(time.Duration(0))
		c.controllerLock.Unlock()
	}()
}

func (c *Controller) playbackTicker(format beep.Format) {
	if c.tickerRunning {
		return
	}
	c.tickerRunning = true
	for {
		c.controllerLock.Lock()
		select {
		case <-c.closeChan:
			c.tickerRunning = false
			c.controllerLock.Unlock()
			return
		default:
			if c.isPlaying && c.stream != nil {
				pos := c.stream.Position()
				songDuration := time.Duration(c.song.Duration) * time.Second
				elapsed := format.SampleRate.D(pos).Round(time.Second)
				if elapsed >= songDuration {
					elapsed = songDuration
					c.songElapsedFunc(elapsed)
					c.tickerRunning = false
					c.controllerLock.Unlock()
					c.songEndedFunc(c.song)
					return
				}
				c.songElapsedFunc(elapsed)
			}
		}
		c.controllerLock.Unlock()
		time.Sleep(time.Second)
	}
}

func (c *Controller) Stream(reader io.Reader, song *subsonic.Child) {
	c.Stop()

	readerCloser := io.NopCloser(reader)
	decodedMp3, format, err := mp3.Decode(readerCloser)
	decodedMp3.Position()
	if err != nil {
		panic("mp3.NewDecoder failed: " + err.Error())
	}

	if c.format == nil {
		c.format = &format
	}

	var stream beep.Streamer = decodedMp3
	if err = speaker.Init(format.SampleRate, format.SampleRate.N(time.Second/10)); err != nil {
		stream = beep.Resample(3, format.SampleRate, c.format.SampleRate, decodedMp3)
	}

	c.stream = decodedMp3
	c.song = song

	ctrl := &beep.Ctrl{Streamer: stream}
	speaker.Play(beep.Seq(ctrl))
	c.ctrl = ctrl
	c.isPlaying = true
	if !c.tickerRunning {
		go c.playbackTicker(format)
	}
}