import {UA as Agent, WebSocketInterface as Socket, debug} from 'jssip';
import EventEmitter from "./eventEmitter";

debug('JsSIP:RTCSession:DTMF');

export default class SipClient extends EventEmitter {
    #debug = false;
    #state = 'unknown';
    #agent = null;
    #session = null;
    #player = null;
    #server = '';

    constructor(opts = {}) {
        super();
        this.#debug = opts.debug || false;
        const player = document.createElement('audio');
        player.autoplay = true;
        this.#player = player;
    }

    register(opts = {server: '', aor: '', displayName: ''}) {
        this.#state = 'unknown';
        this.#agent = this.#session = null;
        this.#server = opts.server;

        this.#initAgent({
            sockets: [new Socket(this.#server)],
            uri: 'sip:' + opts.aor,
            password: opts.password,
            display_name: opts.displayName,
            no_answer_timeout: 50, // 电话呼入无人应答超时
            register: true, // 自动注册
            session_timers: false//启用会话计时器（根据RFC 4028)
        });
        this.#agent.start();
    }

    get debug() {
        return this.#debug;
    }

    set debug(val) {
        this.#debug = val;
    }

    get state() {
        return this.#state;
    }

    get session() {
        return this.#session;
    }

    /**
     * 呼叫
     * @param {string} aor 对方的SIP号码
     */
    call(aor) {
        this.#log('-> 呼叫', aor);
        const opts = {
            mediaConstraints: {audio: true, video: false},
            pcConfig: {iceServers: []},
            eventHandlers: {
                peerconnection: evt => this.#peerConnectionEventHandler(evt),
            }
        }
        this.localSession = this.#agent.call(`sip:${aor}`, opts);
    }

    /**
     * 取消呼叫
     */
    cancel() {
        this.#log('-> 取消')
        if (this.#session) {
            this.#session.terminate();
        } else {
            this.#log('呼出的会话不存在');
        }
    }

    /**
     * 拒绝对方
     */
    decline() {
        this.#log('-> 拒绝')
        if (this.#session) {
            this.#session.terminate();
        } else {
            this.#log('呼入的会话不存在');
        }
    }

    /**
     * 接受对方
     */
    accept() {
        this.#log('-> 接受')
        if (this.#session) {
            this.#session.answer({
                mediaConstraints: {audio: true, video: false},
                pcConfig: {iceServers: []},
            });
        } else {
            this.#log('呼入的会话不存在');
        }
    }

    /**
     * 挂断
     */
    hangup() {
        this.#log('-> 挂断')
        if (this.#session) {
            this.#session.terminate();
        } else {
            this.#log('会话不存在')
        }
    }

    sendDtmf() {

    }

    /**
     * 设置状态
     * @param {string} state
     */
    #setState(state) {
        this.#log('setState', state);
        if(state === 'idle'){
            this.#session = null;
            this.#player.srcObject = null;
        }
        if (this.#state !== state) {
            this.emit('state', state);
        }
        this.#state = state;
    }
    #sessionEventHandler(evt) {
        const {originator, session} = evt;
        if (originator === 'remote') {
            this.remoteSession = session;
            // 如果正在通话中, 回复忙
            if(this.#session){
                session.terminate({
                    status_code: 486
                });
                return;
            }
            const {uri, display_name} = session.remote_identity;
            const remote = {user: uri.user, name: display_name || uri.user, host: uri.host};
            this.emit('callIn', remote);
        }
        session.on('peerconnection', evt => {
            this.#peerConnectionEventHandler(evt);
        }).on('connecting', evt => {
        }).on('progress', evt => {
            this.#log(evt.originator === 'remote' ? '等待对方接听' : '等待自己接听', evt);
            this.#setState('waiting');
        }).on('accepted', evt => {
        }).on('confirmed', evt => {// 确认呼叫后触发
            this.#log(evt.originator === 'remote' ? '自己已接受' : '对方已接受', evt);
            this.#setState('calling');
        }).on('sdp', evt => {
            this.#log(evt.originator === 'remote' ? '对方SDP' : '自己SDP', evt);
        }).on('newDTMF', evt => {
            this.#log('收到DTMF', evt);
        }).on('ended', evt => {
            this.#log(evt.originator === 'remote' ? '对方挂断' : '自己挂断', evt);
            this.#setState('idle');
        }).on('failed', evt => this.#failedEventHandler(evt));
        this.#session = session;
    }

    #peerConnectionEventHandler(evt) {
        this.#log('======peerconnection', evt);
        evt.peerconnection.onaddstream = evt => {
            this.#log('onAddStream', evt.stream.getTracks());
            this.#player.srcObject = evt.stream;
        }
    }

    #failedEventHandler(evt) {
        this.#log('failed', evt.cause, evt);
        const {originator, cause} = evt;
        const isRemote = originator === 'remote';
        switch (cause) {
            case 'Canceled':
                this.#log(isRemote ? '对方已取消' : '自己已取消');
                this.emit('canceled', originator);
                break;
            case 'Unavailable':
                this.#log(isRemote ? '对方不可用' : '自己不可用');
                break;
            case 'No Answer':
                this.#log(isRemote ? '对方无应答' : '自己无应答');
                this.emit('noAnswer');
                break;
            case 'Rejected':
                this.#log(isRemote ? '对方拒绝' : '自己拒绝');
                break;
            case 'SIP Failure Code':
                this.#log(isRemote ? '对方呼叫失败' : '自己呼叫失败');
                break;
            default:
                this.#log('failedEventHandler', cause, originator);
                break;
        }
        this.#setState('idle');
    }

    /**
     * 初始化
     */
    #initAgent(opts = {}) {
        this.#log('createAgent', opts);
        const agent = new Agent(opts);
        agent.on('connected', _ => this.#setState('connected'));
        agent.on('disconnected', _ => this.#setState('disconnected'));
        // 注册成功,data:Response JsSIP.IncomingResponse收到的SIP 2XX响应的实例
        agent.on('registered', _ => this.#setState('idle'));
        agent.on('unregistered', _ => this.#setState('unregistered'));
        //注册失败而被解雇,data:Response JsSIP.IncomingResponse接收到的SIP否定响应的实例，如果失败是由这样的响应的接收产生的，否则为空
        agent.on('registrationFailed', evt => {
            this.#setState('registrationFailed');
        });
        //1.在注册到期之前发射几秒钟。如果应用程序没有为这个事件设置任何监听器，JsSIP将像往常一样重新注册。
        //2.如果应用程序订阅了这个事件，它负责ua.register()在registrationExpiring事件中调用（否则注册将过期）。
        //3.此事件使应用程序有机会在重新注册之前执行异步操作。对于那些在REGISTER请求中的自定义SIP头中使用外部获得的“令牌”的环境很有用。
        agent.on('registrationExpiring', evt => {

        });
        agent.on('newRTCSession', evt => {
            this.#log('newRTCSession', evt);
            this.#sessionEventHandler(evt);
        });
        this.#agent = agent;
    }

    #log(...args) {
        this.#debug && console.log('SipClient', new Date().toLocaleTimeString(), ...args);
    }
}