export const servers = {
    iceServers: [
        {
            urls: ["stun:stun1.l.google.com:19302", "stun:stun2.l.google.com:19302"]
        }
    ],
    iceCandidatePoolSize: 10,
}

let remote_stream: MediaStream, local_stream: MediaStream;
let pc: RTCPeerConnection;

window.onload = async () => {

    if (window.location.search.startsWith("?offer=")) {
        await setup_webrtc()
        await offer(window.location.search.substr("?offer=".length))
    } else if (window.location.search.startsWith("?answer=")) {
        await setup_webrtc()
        await answer(window.location.search.substr("?answer=".length))
    } else {

    }

}

async function setup_webrtc() {
    document.body.innerHTML = ""

    pc = new RTCPeerConnection(servers)

    local_stream = await navigator.mediaDevices.getUserMedia({ video: true, audio: true })
    remote_stream = new MediaStream()

    local_stream.getTracks().forEach(t => pc.addTrack(t, local_stream))

    pc.ontrack = ev => {
        console.log("peer got remote tracks", ev.streams);
        ev.streams[0].getTracks().forEach(t => remote_stream.addTrack(t))
    }


    const ls_el = document.createElement("video")
    const rs_el = document.createElement("video")
    ls_el.muted = true
    ls_el.autoplay = rs_el.autoplay = true
    ls_el.setAttribute("playsinline", "1")
    rs_el.setAttribute("playsinline", "1")
    ls_el.srcObject = local_stream
    rs_el.srcObject = remote_stream

    document.body.append(ls_el, rs_el)

}

interface Offer {
    sdp: any,
    type: any
}

async function offer(id: string) {
    const ws = new WebSocket(`ws://${window.location.host}/offer/${id}`)
    ws.onclose = ev => console.log("websocket closed: " + ev.reason);
    await new Promise<void>(r => ws.onopen = () => r())

    console.log("websocket opened")

    pc.onicecandidate = ev => {
        const candidate = ev.candidate?.toJSON()
        if (!candidate) return
        ws.send(JSON.stringify({ candidate }))
        console.log("sent ice candidate", ev.candidate);
    }

    const offer_description = await pc.createOffer()
    await pc.setLocalDescription(offer_description);

    const offer: Offer = { sdp: offer_description.sdp, type: offer_description.type };

    ws.send(JSON.stringify({ offer }))

    ws.onmessage = ev => {
        const s = JSON.parse(ev.data)
        if (s.answer) {
            console.log("got answer", s.answer);
            const answer_description = new RTCSessionDescription(s.answer)
            pc.setRemoteDescription(answer_description)
        }
        if (s.candidate) {
            console.log("got candidate", s.candidate);
            const candidate = new RTCIceCandidate(s.candidate)
            pc.addIceCandidate(candidate)
        }
    }

}

async function answer(id: string) {
    const ws = new WebSocket(`ws://${window.location.host}/answer/${id}`)
    ws.onclose = ev => console.log("websocket closed: " + ev.reason);
    await new Promise<void>(r => ws.onopen = () => r())
    console.log("websocket opened");


    pc.onicecandidate = ev => {
        const candidate = ev.candidate?.toJSON()
        if (!candidate) return
        ws.send(JSON.stringify({ candidate }))
        console.log("sent ice candidate", candidate);
    }

    ws.onmessage = async ev => {
        const s = JSON.parse(ev.data)
        if (s.offer) {
            console.log("got offer", s.offer);
            await pc.setRemoteDescription(new RTCSessionDescription(s.offer))

            const answer_description = await pc.createAnswer()
            await pc.setLocalDescription(answer_description)

            const answer: Offer = { type: answer_description.type, sdp: answer_description.sdp }
            ws.send(JSON.stringify({ answer }))
        }
        if (s.candidate) {
            console.log("got candidate", s.candidate);
            pc.addIceCandidate(new RTCIceCandidate(s.candidate))
        }
    }
}