import io from 'socket.io-client';

 /**
  * The Class Responsible for Talking with Polyglot-Node
  * @param {string} url - URL of NodeJS Server.
  */
export default class NodeSocket {
  constructor(url) {
    this.io = io(url);
    this.listen();
  }

  /**
   * Create socket.io event listeners.
   */
  listen() {
    this.io.on('disconnect', (err) => {
      console.error("Disconnected from Server.");
    })

   this.io.on('connect', (data) => {
     this.io.emit("join", "Hi There NodeJS!");
     console.log("Connected to NodeJS Server");
   });
  }
  /**
   * This Class Grabs the Audio from the User.
   *
   * DEPRECAION WARNING. This method makes vital use of createScriptProcessor which will be scrapped at some point
   * in the future. TODO: Switch from createScriptProcessor to AudioWorklet (No documentation as of 2018-08-30)
   * @deprecated
   * @param {MediaStream} stream - Global MediaStream
   * @async
   */
  async grabAudio(stream) {
    this.io.emit('startRecognition', "en-US", "fr");

    AudioContext = window.AudioContext || window.webkitAudioContext;
    const ctx = new AudioContext();
    const processor = ctx.createScriptProcessor(2048, 1, 1);
    processor.connect(ctx.destination);
    processor.onaudioprocess = e => this.handleBuffer(e);

    // const stream = await navigator.mediaDevices.getUserMedia({ audio: true, video: false });
    ctx.createMediaStreamSource(stream).connect(processor);
    ctx.resume();
  }

  /**
   * Takes the Float32Array  Array from the ScriptProcessor Event
   * and converts it to Int16 for Google Speech to Text use.
   * @param {AudioProcessingEvent} e Chunk of Audio w/ Audio F32Array
   */
  handleBuffer(e) {
    let l = e.inputBuffer.getChannelData(0);
    this.io.emit('binary', convertF32ToI16(l));

    /**
     * 32Khz to 16Khz Audio
     * Converts Float32 Buffer to Int16Buffer
     * @param {Float32Array} buffer - Float32 Buffer;
     * @returns {ArrayBuffer}
     */
    function convertF32ToI16(buffer) {
      let l = buffer.length;

      let buf = new Int16Array(l/3);

      while (l--) {
        if (l % 3 == 0) {
          buf[l / 3] = buffer[l] * 0xFFFF;
        }
      }
      return buf.buffer;
    }
  }
}