Send local participant SID with reconnect=1. (#558)

Also, some minor clean up as room was reaching into client and setting a
callback (for track unpublished) which was also going through engine.
Just make it so that the chain is always room -> engine -> signalclient.

engine.go

@@ -68,6 +68,7 @@ type RTCEngine struct {
 
 	// callbacks
 	OnLocalTrackUnpublished func(response *livekit.TrackUnpublishedResponse)
+	OnTrackRemoteMuted      func(request *livekit.MuteTrackRequest)
 	OnDisconnected          func(reason DisconnectionReason)
 	OnMediaTrack            func(track *webrtc.TrackRemote, receiver *webrtc.RTPReceiver)
 	OnParticipantUpdate     func([]*livekit.ParticipantInfo)
@@ -80,6 +81,9 @@ type RTCEngine struct {
 	OnRestarted             func(*livekit.JoinResponse)
 	OnResuming              func()
 	OnResumed               func()
+
+	// callbacks to get data
+	CbGetLocalParticipantSID func() string
 }
 
 func NewRTCEngine() *RTCEngine {
@@ -102,6 +106,7 @@ func NewRTCEngine() *RTCEngine {
 	}
 	e.client.OnLocalTrackPublished = e.handleLocalTrackPublished
 	e.client.OnLocalTrackUnpublished = e.handleLocalTrackUnpublished
+	e.client.OnTrackRemoteMuted = e.handleTrackRemoteMuted
 	e.client.OnConnectionQuality = func(cqi []*livekit.ConnectionQualityInfo) {
 		if f := e.OnConnectionQuality; f != nil {
 			f(cqi)
@@ -501,6 +506,12 @@ func (e *RTCEngine) handleLocalTrackUnpublished(res *livekit.TrackUnpublishedRes
 	}
 }
 
+func (e *RTCEngine) handleTrackRemoteMuted(request *livekit.MuteTrackRequest) {
+	if e.OnTrackRemoteMuted != nil {
+		e.OnTrackRemoteMuted(request)
+	}
+}
+
 func (e *RTCEngine) handleDataPacket(msg webrtc.DataChannelMessage) {
 	packet, err := e.readDataPacket(msg)
 	if err != nil {
@@ -605,7 +616,7 @@ func (e *RTCEngine) handleDisconnect(fullReconnect bool) {
 }
 
 func (e *RTCEngine) resumeConnection() error {
-	reconnect, err := e.client.Reconnect(e.url, e.token.Load(), *e.connParams)
+	reconnect, err := e.client.Reconnect(e.url, e.token.Load(), *e.connParams, e.CbGetLocalParticipantSID())
 	if err != nil {
 		return err
 	}

room.go

@@ -197,8 +197,11 @@ func NewRoom(callback *RoomCallback) *Room {
 	engine.OnRestarted = r.handleRestarted
 	engine.OnResuming = r.handleResuming
 	engine.OnResumed = r.handleResumed
-	engine.client.OnLocalTrackUnpublished = r.handleLocalTrackUnpublished
-	engine.client.OnTrackRemoteMuted = r.handleTrackRemoteMuted
+	engine.OnLocalTrackUnpublished = r.handleLocalTrackUnpublished
+	engine.OnTrackRemoteMuted = r.handleTrackRemoteMuted
+
+	// callbacks engine can use to get data
+	engine.CbGetLocalParticipantSID = r.getLocalParticipantSID
 
 	return r
 }
@@ -818,6 +821,12 @@ func (r *Room) Simulate(scenario SimulateScenario) {
 	}
 }
 
+func (r *Room) getLocalParticipantSID() string {
+	return r.LocalParticipant.SID()
+}
+
+// ---------------------------------------------------------
+
 func unpackStreamID(packed string) (participantId string, trackId string) {
 	parts := strings.Split(packed, "|")
 	if len(parts) > 1 {

signalclient.go

@@ -82,7 +82,7 @@ func (c *SignalClient) IsStarted() bool {
 }
 
 func (c *SignalClient) Join(urlPrefix string, token string, params connectParams) (*livekit.JoinResponse, error) {
-	res, err := c.connect(urlPrefix, token, params)
+	res, err := c.connect(urlPrefix, token, params, "")
 	if err != nil {
 		return nil, err
 	}
@@ -97,9 +97,9 @@ func (c *SignalClient) Join(urlPrefix string, token string, params connectParams
 
 // Reconnect starts a new WebSocket connection to the server, passing in reconnect=1
 // when successful, it'll return a ReconnectResponse; older versions of the server will not send back a ReconnectResponse
-func (c *SignalClient) Reconnect(urlPrefix string, token string, params connectParams) (*livekit.ReconnectResponse, error) {
+func (c *SignalClient) Reconnect(urlPrefix string, token string, params connectParams, participantSID string) (*livekit.ReconnectResponse, error) {
 	params.Reconnect = true
-	res, err := c.connect(urlPrefix, token, params)
+	res, err := c.connect(urlPrefix, token, params, participantSID)
 	if err != nil {
 		return nil, err
 	}
@@ -121,7 +121,7 @@ func (c *SignalClient) Reconnect(urlPrefix string, token string, params connectP
 	return nil, nil
 }
 
-func (c *SignalClient) connect(urlPrefix string, token string, params connectParams) (*livekit.SignalResponse, error) {
+func (c *SignalClient) connect(urlPrefix string, token string, params connectParams, participantSID string) (*livekit.SignalResponse, error) {
 	if urlPrefix == "" {
 		return nil, ErrURLNotProvided
 	}
@@ -135,6 +135,9 @@ func (c *SignalClient) connect(urlPrefix string, token string, params connectPar
 	}
 	if params.Reconnect {
 		urlSuffix += "&reconnect=1"
+		if participantSID != "" {
+			urlSuffix += fmt.Sprintf("&sid=%s", participantSID)
+		}
 	}
 	urlSuffix += getStatsParamString()