How to Switch Camera webrtc Android

So I am building a android video call app using webrtc I have implemented every thing and tested the video call feature from my app it works like charm. But now I want to implement where the user can switch camera from rear to front and vice verse. I have seen a similar answer it was not for android it said to remove the stream and negotiate and new stream I didnt properly understand how to implement that in this code so I hope someone can help me with that thing Thank you

JavaScript File

localVideo.style.opacity = 0
remoteVideo.style.opacity = 0

localVideo.onplaying = () => { localVideo.style.opacity = 1 }
remoteVideo.onplaying = () => { remoteVideo.style.opacity = 1 }

let peer
function init(userId) {
     peer = new Peer(userId, {
        host: 'messenger-by-margs-video-call.herokuapp.com',
        secure: true
    })

    peer.on('open', () => {
        Android.onPeerConnected()
    })

    listen()
}

let localStream
function listen() {
    peer.on('call', (call) => {

        navigator.getUserMedia({
            audio: true, 
            video: true
        }, (stream) => {
            localVideo.srcObject = stream
            localStream = stream

            call.answer(stream)
            call.on('stream', (remoteStream) => {
                remoteVideo.srcObject = remoteStream

                remoteVideo.className = "primary-video"
                localVideo.className = "secondary-video"

            })

        })
        
    })
}

function startCall(otherUserId) {
    navigator.getUserMedia({
        audio: true,
        video: true
    }, (stream) => {

        localVideo.srcObject = stream
        localStream = stream

        const call = peer.call(otherUserId, stream)
        call.on('stream', (remoteStream) => {
            remoteVideo.srcObject = remoteStream

            remoteVideo.className = "primary-video"
            localVideo.className = "secondary-video"
        })

    })
}

function toggleVideo(b) {
    if (b == "true") {
        localStream.getVideoTracks()[0].enabled = true
    } else {
        localStream.getVideoTracks()[0].enabled = false
    }
} 

function toggleAudio(b) {
    if (b == "true") {
        localStream.getAudioTracks()[0].enabled = true
    } else {
        localStream.getAudioTracks()[0].enabled = false
    }
} 

Heres my kotlin activity file.

class CallActivity : AppCompatActivity() {

    var username = ""
    var friendsUsername = ""

    var isPeerConnected = false

    var firebaseRef = FirebaseDatabase.getInstance().getReference("Users")

    var isAudio = true
    var isVideo = true




    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_video_call)


        username = FirebaseAuth.getInstance().uid.toString();
        friendsUsername = intent.getStringExtra("userid")!!




        call.setOnClickListener {
            sendCallRequest()
        }





        toggleAudioBtn.setOnClickListener {
            isAudio = !isAudio
            callJavascriptFunction("javascript:toggleAudio(\"${isAudio}\")")
            toggleAudioBtn.setImageResource(if (isAudio) R.drawable.ic_baseline_mic_24 else R.drawable.ic_baseline_mic_off_24 )
        }

        toggleVideoBtn.setOnClickListener {
            isVideo = !isVideo
            callJavascriptFunction("javascript:toggleVideo(\"${isVideo}\")")
            toggleVideoBtn.setImageResource(if (isVideo) R.drawable.ic_baseline_videocam_24 else R.drawable.ic_baseline_videocam_off_24 )
        }

        setupWebView()
    }



    private fun sendCallRequest() {
        if (!isPeerConnected) {
            Toast.makeText(this, "You're not connected. Check your internet", Toast.LENGTH_LONG).show()
            return
        }

        firebaseRef.child(friendsUsername).child("videocall").child("incall").setValue(username)
        firebaseRef.child(friendsUsername).child("videocall").child("isAvailable").addValueEventListener(object: ValueEventListener {
            override fun onCancelled(error: DatabaseError) {}

            override fun onDataChange(snapshot: DataSnapshot) {

                if (snapshot.value.toString() == "true") {
                    listenForConnId()
                }

            }

        })

    }

    private fun listenForConnId() {
        firebaseRef.child(friendsUsername).child("videocall").child("connId").addValueEventListener(object: ValueEventListener {
            override fun onCancelled(error: DatabaseError) {}

            override fun onDataChange(snapshot: DataSnapshot) {
                if (snapshot.value == null)
                    return
                switchToControls()
                callJavascriptFunction("javascript:startCall(\"${snapshot.value}\")")
            }

        })
    }

    @SuppressLint("SetJavaScriptEnabled")
    private fun setupWebView() {

        webView.webChromeClient = object: WebChromeClient() {
            override fun onPermissionRequest(request: PermissionRequest?) {
                request?.grant(request.resources)
            }
        }

        webView.settings.javaScriptEnabled = true
        webView.settings.mediaPlaybackRequiresUserGesture = false
        webView.addJavascriptInterface(JavascriptInterface(this), "Android")

        loadVideoCall()
    }

    private fun loadVideoCall() {
        val filePath = "file:android_asset/call.html"
        webView.loadUrl(filePath)

        webView.webViewClient = object: WebViewClient() {
            override fun onPageFinished(view: WebView?, url: String?) {
                initializePeer()
            }
        }
    }

    var uniqueId = ""

    private fun initializePeer() {

        uniqueId = getUniqueID()

        callJavascriptFunction("javascript:init(\"${uniqueId}\")")
        firebaseRef.child(username).child("videocall").child("incall").addValueEventListener(object: ValueEventListener {
            override fun onCancelled(error: DatabaseError) {}

            override fun onDataChange(snapshot: DataSnapshot) {
                onCallRequest(snapshot.value as? String)
            }

        })

    }

    private fun onCallRequest(caller: String?) {
        if (caller == null) return

        callLayout.visibility = View.VISIBLE
        incomingCallTxt.text = "$caller is calling..."

        acceptBtn.setOnClickListener {
            firebaseRef.child(username).child("videocall").child("connId").setValue(uniqueId)
            firebaseRef.child(username).child("videocall").child("isAvailable").setValue(true)

            callLayout.visibility = View.GONE
            switchToControls()
        }

        rejectBtn.setOnClickListener {
            firebaseRef.child(username).child("videocall").child("incall").setValue(null)
            callLayout.visibility = View.GONE
        }

    }

    private fun switchToControls() {
        //inputLayout.visibility = View.GONE
        call.visibility = View.INVISIBLE
        callControlLayout.visibility = View.VISIBLE

    }


    private fun getUniqueID(): String {
        return UUID.randomUUID().toString()
    }

    private fun callJavascriptFunction(functionString: String) {
        webView.post { webView.evaluateJavascript(functionString, null) }
    }


    fun onPeerConnected() {
        isPeerConnected = true
    }

}

I hope these are necessary information to my answer