import { IWebrtcTextSimple } from "../type";
import { base64ToArray } from "../utils";
import SignalSimple from "./signal-simple";

export default class WebRtcTextSimple {
  private _peerConnection?: RTCPeerConnection;
  private _pcConfig?:  any;
  private _signal?: SignalSimple;
  private _imageElement?: HTMLImageElement;
  private buildTextOfferMessage?: (desc: RTCSessionDescriptionInit) => any;
  private buildTextCandidateMessage?: (candidate: any) => any;
  private _imageStreamChannel?: RTCDataChannel;
  private readonly _earlyCandidates: RTCIceCandidate[];

  public constructor(option: IWebrtcTextSimple) {
    this._pcConfig = option?.iceConfig;
    this._imageElement = option.imageElement;
    this._earlyCandidates = [];
    this.buildTextCandidateMessage = option.buildTextCandidateMessage?.bind(this);
    this.buildTextOfferMessage = option.buildTextOfferMessage?.bind(this);
  }

  public peerConnection() {
    return this._peerConnection;
  }

  // 设置信令
  public setSignal = (signal: SignalSimple) => {
    this._signal = signal;
  }

  get imageStreamChannel() {
    return this._imageStreamChannel;
  }

  // gatherCandidate作为CandidateFromWeb然后由信令发送
  private _gatherCandidate = (event: RTCPeerConnectionIceEvent) => {
    if (event.candidate && this._peerConnection) {
      if (this._peerConnection.currentRemoteDescription) {
        this._signal && this.buildTextCandidateMessage && this._signal?.sendMsg(this.buildTextCandidateMessage(event.candidate));
      } else {
        this._earlyCandidates.push(event.candidate);
      }
    } else {
      console.log('WebrtcText: IceCandidate 发送完毕');
    }
  };

  // 创建发送Offer
  private _handleCreateOffer() {
    this._peerConnection && this._peerConnection.createOffer().then(
      sessionDescription => {
        this._peerConnection &&
          this._peerConnection
            .setLocalDescription(sessionDescription)
            .then(() => {
              this._signal && this.buildTextOfferMessage && this._signal?.sendMsg(this.buildTextOfferMessage(sessionDescription));
            })
            .catch(error =>
              console.error(`WebrtcText: SetLocalDescription 失败${JSON.stringify(error, undefined, 2)}`)
            );
      },
      function (error) {
        console.error(`WebrtcText: 创建Offer失败${JSON.stringify(error, undefined, 2)}`);
      }
    );
  }

  // 初始化peerConnection并创建发送Offer
  public initPeer = () => {
    this._peerConnection = new RTCPeerConnection();
    // 如果需要createDataChannel, 需要在setDescription之前先create至少一个channel，否则后续一直无法open
    this._peerConnection.createDataChannel('preserveChannel');
    if (this._pcConfig) {
      this._peerConnection.setConfiguration(this._pcConfig);
    } else {
      this._peerConnection.setConfiguration({
        "iceServers":[{"urls":"turn:test.udt.woa.com:3478?transport=udp","credential":"udt@wetest","username":"udt"},{"urls":"turn:test.udt.woa.com:3478?transport=tcp","credential":"udt@wetest","username":"udt"},{"urls":"turn:119.29.18.254:3478?transport=udp","credential":"fEcGCPLqhYcj3JlYQnMgQpaLnXMhyQGF","username":"udt-public"}]})
    }
    if (this._peerConnection?.iceConnectionState !== 'connected') {
      this._handleCreateOffer();
    }
    this._peerConnection.onicecandidate = this._gatherCandidate;
  }

  // 收到Answer后,SetRemoteDescription并开始发送Candidate
  public handleReceiveAnswer = (descriptionInitDict: RTCSessionDescriptionInit) => {
    const descr = new RTCSessionDescription(descriptionInitDict);
    if (this._peerConnection?.iceConnectionState !== 'connected') {
      this._peerConnection &&
        this._peerConnection
          .setRemoteDescription(descr)
          .then(() => {
            while (this._earlyCandidates.length) {
              const candidate = this._earlyCandidates.shift();
              this._peerConnection && this._signal && this.buildTextCandidateMessage && this._signal?.sendMsg(this.buildTextCandidateMessage(candidate));
            }
          })
          .catch(error => {
            console.error(`WebrtcText: 设置 RemoteDescription 失败${JSON.stringify(error, undefined, 2)}`);
          });
    }
  }

  // 收到CandidateFromDevice后,回调addIceCandidate
  public handleReceiveCandidate = (candidate: any) => {
    const candidateNew = new RTCIceCandidate(candidate);
    this._peerConnection &&
      this._peerConnection
        .addIceCandidate(candidateNew)
        .then(() => {
          console.log('WebrtcText: 添加 Ice Candidate 成功');
        })
        .catch(error => {
          console.error(`WebrtcText: 添加 Ice Candidate 失败 ${JSON.stringify(error, undefined, 2)}`);
        });
  }

  public requestImageChannel = () => {
    if (this._imageStreamChannel) {
      return;
    }
    this._imageStreamChannel = this._peerConnection?.createDataChannel('wsctrl');
    this._imageStreamChannel && this._imageStreamChannel.addEventListener('open', () => {
      console.log('imageChannel-----------------------', 'imageChannel open');
    });
    let toRead = 0;
    let pendingDataView: any;
    let hasRead = 0;
    const decoder = new TextDecoder();
    this._imageStreamChannel && this._imageStreamChannel.addEventListener('message', (e) => {
      const { data } = e;
      if (data.byteLength === 4 && !toRead) {
        const view = new DataView(data);
        const targetRead = view.getInt32(0, false);
        toRead = targetRead;
        console.log(targetRead, 'toRead');
        pendingDataView = new Uint8Array(new ArrayBuffer(toRead));
      } else if (toRead - hasRead >= data.byteLength) {
        const curretDataView = new Uint8Array(data);
        (pendingDataView as Uint8Array).set(curretDataView, hasRead);
        hasRead += data.byteLength;
      }
      if (hasRead === toRead) {
        toRead = 0;
        hasRead = 0;
        const result = decoder.decode(pendingDataView);
        const json = JSON.parse(result);
        if (json['type'] == '0') {
          const image = json['image'];
          const blob = base64ToArray(image);
          const url = URL.createObjectURL(blob);
          if (this._imageElement) {
            this._imageElement.src = url;
          }
        }
        pendingDataView = undefined;
      }
    });
  }
}