var MicrophonePlugin = {

  buffer: undefined,

  Init: function() {

    console.log("Init:");
  
	// START - used to read the volume
	document.volume = 0;
	var byteOffset = 0;
	var length = 1024;
	this.buffer = new ArrayBuffer(4 * length);
    document.dataArray = new Float32Array(this.buffer, byteOffset, length);
	// END - used to read the volume

	navigator.getUserMedia = navigator.getUserMedia || navigator.webkitGetUserMedia || navigator.mozGetUserMedia;

	if (navigator.getUserMedia) {
  
		var constraints = {
		  audio: {
			optional: [{
			  sourceId: "audioSource"
			}]
		  }
		};
		navigator.getUserMedia(constraints, function(stream) {
		  console.log('navigator.getUserMedia successCallback: ', stream);
	  
		  document.position = 0;

		  document.audioContext = new AudioContext();
		  document.tempSize = 1024;
		  document.tempArray = new Float32Array(document.tempSize)
		  document.analyser = document.audioContext.createAnalyser();
		  document.analyser.minDecibels = -90;
		  document.analyser.maxDecibels = -10;
		  document.analyser.smoothingTimeConstant = 0.85;

		  document.mediaRecorder = new MediaRecorder(stream);

		  document.source = document.audioContext.createMediaStreamSource(stream);

		  document.source.connect(document.analyser);

		  document.mediaRecorder.start();
		  console.log(document.mediaRecorder.state);

		  document.readDataOnInterval = function() {

			if (document.dataArray == undefined) {
			  setTimeout(document.readDataOnInterval, 250); //wait to be set
			  return;
			}

			document.tempInterval = Math.floor(document.tempSize / document.dataArray.length * 250);

			// read the next chunk after interval
			setTimeout(document.readDataOnInterval, document.tempInterval); //if mic is still active

			if (document.dataArray == undefined) {
			  return;
			}

			//read the temp data buffer
			document.analyser.getFloatTimeDomainData(document.tempArray);

			// use the amplitude to get volume
            document.volume = 0;

			var j = (document.position + document.dataArray.length - document.tempSize) % document.dataArray.length;
			for (var i = 0; i < document.tempSize; ++i) {
			  document.volume = Math.max(document.volume, Math.abs(document.tempArray[i]));
			  document.dataArray[j] = document.tempArray[i];
			  j = (j + 1) % document.dataArray.length;
			}
			document.position = (document.position + document.tempSize) % document.dataArray.length;

		  };

		  document.readDataOnInterval();


		}, function(error) {
		  console.error('navigator.getUserMedia errorCallback: ', error);
		});
	}
  },
  
  QueryAudioInput: function() {

    console.log("QueryAudioInput");

    document.mMicrophones = [];

    if (!navigator.mediaDevices || !navigator.mediaDevices.enumerateDevices) {
      console.log("enumerateDevices() not supported.");
    } else {
      // List microphones
      navigator.mediaDevices.enumerateDevices()
      .then(function(devices) {
        devices.forEach(function(device) {
          console.log("QueryAudioInput: kind="+device.kind + " device=", device, " label=" + device.label);
          if (device.kind === 'audioinput') {
            document.mMicrophones.push(device.label);
          }
        });
      })
      .catch(function(err) {
        console.error(err.name + ": " + err.message);
      });
    }
  },
  
  GetNumberOfMicrophones: function() {
    console.log("GetNumberOfMicrophones");
	var microphones = document.mMicrophones;
    if (microphones == undefined) {
	  console.log("GetNumberOfMicrophones", 0);
      return 0;
    }  
    console.log("GetNumberOfMicrophones length="+microphones.length);
    return microphones.length;
  },
  
  GetMicrophoneDeviceName: function(index) {
	//console.log("GetMicrophoneDeviceName");
	var returnStr = "Not Set";
	var microphones = document.mMicrophones;
    if (microphones != undefined) {
      if (index >= 0 && index < microphones.length) {
	    if (microphones[index] != undefined) {
		  returnStr = microphones[index];
		}
      }
    }  
	console.log("GetMicrophoneDeviceName", returnStr);
    var buffer = _malloc(lengthBytesUTF8(returnStr) + 1);
    writeStringToMemory(returnStr, buffer);
    return buffer;
  },

  GetMicrophoneVolume: function(index) {
	console.log("GetMicrophoneVolume");
    if (document.volume == undefined) {
	   return 0;
	}
	console.log("GetMicrophoneVolume", document.volume);
    return document.volume;
  }
};

mergeInto(LibraryManager.library, MicrophonePlugin);