let context: any;
export default class Audio {
  static instance: any;
  context: any;

  constructor() {
    if (!Audio.instance) {
      Audio.instance = this;
      try {
        window['AudioContext'] = window['AudioContext'] || window['webkitAudioContext'];
        Audio.AudioContext = this.context = new window['AudioContext()'];
      } catch (e) {
        alert(e);
      }
    } else {
      this.context = Audio.AudioContext;
    }
  }

  static createCompressor() {
    let time = context.currentTime;
    let compressor = context.createDynamicsCompressor();
    compressor.threshold.setValueAtTime(-24, time);
    compressor.knee.setValueAtTime(30, time);
    compressor.ratio.setValueAtTime(12, time);
    compressor.attack.setValueAtTime(0.003, time);
    compressor.release.setValueAtTime(0.25, time);
    return compressor;
  }

  static get Destination() {
    return context.destination;
  }

  static get Instance() {
    if (Audio.instance) {
      return Audio.instance;
    } else {
      return new Audio();
    }
  }

  static set AudioContext(v: any) {
    context = v;
  }

  static get AudioContext(): any {
    return context;
  }

  static getContext() {
    if (context) {
      return context;
    } else {
      return new Audio().context;
    }
  }

  static frequencyFromNoteNumber(note) {
    return 440 * Math.pow(2, (note - 127) / 12);
  };
}