// wrt + socket + contrl
const io = require("socket.io-client")
const PWM = require('./lib/Pwm')
const { PeerConnection, Video } = require('node-datachannel');
const { createSocket } = require('dgram')
const { spawn } = require('child_process')

const url = 'ws://10.10.3.196:7896'
class CarServer {
    constructor() {
        this.Peer = null
        this.track = null
        this.child = null
        this.udp = null
        this.socket = io(url, { auth: { roomID: "feiCar", name: 'car' } });
        this.socket.on('connect', this.connected.bind(this))
        this.socket.on('msg', this.onMsg.bind(this))
        this.socket.on('leaved', this.onLeved.bind(this))
        this.socket.on('joined', this.startVideo.bind(this))
        this.socket.on('disconnect',this.onLeved.bind(this))
    }
    
    // socket 连接
    connected() {
        console.log('connected');
        this.Peer = new PeerConnection("Peer1", { iceServers: [] });
        // 发送offer
        this.Peer.onGatheringStateChange(state => {
            console.log('GatheringState: ', state);
            if (state === 'complete') {
                const offer = this.Peer.localDescription();
                this.socket.emit("msg", offer);
            }
        })
    }

    // 用户信息
    onMsg(data) {
        try {
            if (data.type == 'answer') {
                this.Peer.setRemoteDescription(data.sdp, data.type);
            } else if (data.type === 'startRTC') {
                this.startVideo()
            } if (data.type === 'conctrl') {
                const state = this.Peer.state();
                if(state === 'connected') PWM.changPWM(data.conctrl);
            }
        } catch (error) {
            console.log(error);
            throw error
        }
    }

    // 用户离开
    onLeved() {
        if (this.child) this.child.kill()
        if (this.udp) this.udp.close()
        PWM.stop()
        this.child = null
        this.udp = null
        process.exit(1)
    }

    // 开始视频
    startVideo() {
        try {
            if (this.child) this.child.kill()
            if (this.udp) this.udp.close()

            // test video
            const video = new Video('video', 'SendOnly')
            video.addH264Codec(96)
            video.addSSRC(42, "video-send")
            this.track = this.Peer.addTrack(video)
            this.Peer.setLocalDescription()

            // UDP server
            const port = 7788
            this.udp = createSocket("udp4")
            this.udp.bind(port)

            // video push
            const args = [
                "libcamerasrc",
                "video/x-raw,width=960,height=720",
                "videoconvert",
                "queue",
                "x264enc tune=zerolatency bitrate=1000 key-int-max=30 speed-preset=1",
                "video/x-h264, profile=constrained-baseline",
                "rtph264pay pt=96 mtu=1200 ssrc=42",
                `udpsink host=127.0.0.1 port=${port}`,
            ].join(" ! ").split(" ")
            this.child = spawn("gst-launch-1.0", args)

            // listen UDP
            this.udp.on("message", (data) => {
                if (!this.track.isOpen()) return
                this.track.sendMessageBinary(data)
            });

        } catch (error) {
            console.log(error);
            throw error
        }
    }
}
new CarServer()