// polyfill
var AudioContext = window.AudioContext || window.webkitAudioContext || window.mozAudioContext;

function Tone(context, freq1, freq2) {
  this.context = context;
  this.status = 0;
  this.freq1 = freq1;
  this.freq2 = freq2;
}

Tone.prototype.setup = function() {
	this.osc1 = context.createOscillator();
	this.osc2 = context.createOscillator();
	this.osc1.frequency.value = this.freq1;
	this.osc2.frequency.value = this.freq2;

	this.gainNode = this.context.createGain();
	this.gainNode.gain.value = 0.25;

	this.filter = this.context.createBiquadFilter();
	this.filter.type = "lowpass";
	this.filter.frequency = 8000;

	this.osc1.connect(this.gainNode);
	this.osc2.connect(this.gainNode);

	this.gainNode.connect(this.filter);
	this.filter.connect(context.destination);
}

Tone.prototype.start = function() {
  this.setup();
  this.osc1.start(0);
  this.osc2.start(0);
  this.status = 1;
}

Tone.prototype.stop = function() {
  this.osc1.stop(0);
  this.osc2.stop(0);
  this.status = 0;
}

Tone.prototype.createRingerLFO = function() {
  // Create an empty 3 second mono buffer at the
  // sample rate of the AudioContext
  var channels = 1;
  var sampleRate = this.context.sampleRate;
  var frameCount = sampleRate * 3;
  var myArrayBuffer = this.context.createBuffer(channels, frameCount, sampleRate);

  // getChannelData allows us to access and edit the buffer data and change.
  var bufferData = myArrayBuffer.getChannelData(0);
  for (var i = 0; i < frameCount; i++) {
    // if the sample lies between 0 and 0.4 seconds, or 0.6 and 1 second, we want it to be on.
    if ((i / sampleRate > 0 && i / sampleRate < 0.4) || (i / sampleRate > 0.6 && i / sampleRate < 1.0)) {
      bufferData[i] = 0.25;
    }
  }

  this.ringerLFOBuffer = myArrayBuffer;
}

Tone.prototype.startRinging = function() {
  this.start();
  // set our gain node to 0, because the LFO is callibrated to this level
  this.gainNode.gain.value = 0;
  this.status = 1;

  this.createRingerLFO();

  this.ringerLFOSource = this.context.createBufferSource();
  this.ringerLFOSource.buffer = this.ringerLFOBuffer;
  this.ringerLFOSource.loop = true;
  // connect the ringerLFOSource to the gain Node audio param
  this.ringerLFOSource.connect(this.gainNode.gain);
  this.ringerLFOSource.start(0);
}

Tone.prototype.stopRinging = function() {
  this.stop();
  this.ringerLFOSource.stop(0);
}

var context = new AudioContext();
var ringbackTone = new Tone(context, 400, 450);
$("#js-toggle-ringback-tone").click(function(e) {
  e.preventDefault();
  if (ringbackTone.status === 0) {
    // The tone is currently off, so we need to turn it on.
    ringbackTone.startRinging();
  } else {
    // The tone is currently on, so we need to turn it off.
    ringbackTone.stopRinging();
  }
});