telegabber/calls/audio/ntgadapter/adapter.go

// adapts *ntgcalls.Client to audio.NtgClient; sub-package so audio/ stays
// buildable without libntgcalls/CGO locally
package ntgadapter

import (
	"sync"

	"dev.narayana.im/narayana/telegabber/calls/audio"
	"gotgcalls/ntgcalls"
)

// wraps *ntgcalls.Client and filters OnFrame to (Playback, Microphone) -
// the bridge only wants the peer's audio coming back via the external mic
type Adapter struct {
	c *ntgcalls.Client

	mu       sync.RWMutex
	handlers map[uint64]audio.NtgFrameHandler
	nextID   uint64
	wired    bool
}

func New(c *ntgcalls.Client) *Adapter {
	return &Adapter{c: c, handlers: make(map[uint64]audio.NtgFrameHandler)}
}

// lazily wires the ntgcalls callback on first call; cancel drops from
// the adapter-owned dispatch table (C++ binding's OnFrame is append-only)
func (a *Adapter) OnFrame(h audio.NtgFrameHandler) func() {
	a.mu.Lock()
	id := a.nextID
	a.nextID++
	a.handlers[id] = h
	wire := !a.wired
	a.wired = true
	a.mu.Unlock()

	if wire {
		a.c.OnFrame(func(chatID int64, mode ntgcalls.StreamMode, device ntgcalls.StreamDevice, frames []ntgcalls.Frame) {
			if mode != ntgcalls.PlaybackStream || device != ntgcalls.MicrophoneStream {
				return
			}
			pcm := make([]audio.PCMFrame, 0, len(frames))
			for _, f := range frames {
				pcm = append(pcm, audio.PCMFrame{SSRC: f.Ssrc, Data: f.Data})
			}
			a.mu.RLock()
			hs := make([]audio.NtgFrameHandler, 0, len(a.handlers))
			for _, h := range a.handlers {
				hs = append(hs, h)
			}
			a.mu.RUnlock()
			for _, h := range hs {
				h(chatID, pcm)
			}
		})
	}

	return func() {
		a.mu.Lock()
		delete(a.handlers, id)
		a.mu.Unlock()
	}
}

// uses the Microphone device slot in both directions (ntgcalls P2P pattern)
func (a *Adapter) SetExternalMicrophone(chatID int64, capture bool, sampleRate uint32, channels uint8) error {
	desc := ntgcalls.MediaDescription{
		Microphone: &ntgcalls.AudioDescription{
			MediaSource:  ntgcalls.MediaSourceExternal,
			SampleRate:   sampleRate,
			ChannelCount: channels,
		},
	}
	mode := ntgcalls.PlaybackStream
	if capture {
		mode = ntgcalls.CaptureStream
	}
	return a.c.SetStreamSources(chatID, mode, desc)
}

// errors only if both clears fail; partial cleanup is best-effort
func (a *Adapter) ClearStreams(chatID int64) error {
	empty := ntgcalls.MediaDescription{}
	capErr := a.c.SetStreamSources(chatID, ntgcalls.CaptureStream, empty)
	pbErr := a.c.SetStreamSources(chatID, ntgcalls.PlaybackStream, empty)
	if capErr != nil && pbErr != nil {
		return capErr
	}
	return nil
}

func (a *Adapter) SendMicrophonePCM(chatID int64, pcm []byte) error {
	return a.c.SendExternalFrame(chatID, ntgcalls.MicrophoneStream, pcm, ntgcalls.FrameData{})
}

var _ audio.NtgClient = (*Adapter)(nil)