/*

The MIT License (MIT)

Copyright (c) 2014 Chris Wilson

Permission is hereby granted, free of charge, to any person obtaining a copy

of this software and associated documentation files (the "Software"), to deal

in the Software without restriction, including without limitation the rights

to use, copy, modify, merge, publish, distribute, sublicense, and/or sell

copies of the Software, and to permit persons to whom the Software is

furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all

copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE

AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,

OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE

SOFTWARE.

*/

var audioContext = null;

var meter = null;

var canvasContext = null;

var WIDTH=500;

var HEIGHT=50;

var rafID = null;

window.onload = function() {

  // grab our canvas

  var canvas = document.getElementById("meter");

	canvasContext = canvas.getContext("2d");

	WIDTH = canvas.width;

	HEIGHT = canvas.height;

    // monkeypatch Web Audio

    window.AudioContext = window.AudioContext || window.webkitAudioContext;

    // grab an audio context

    audioContext = new AudioContext();

    // Attempt to get audio input

    try {

        // monkeypatch getUserMedia

        navigator.getUserMedia = 

        	navigator.getUserMedia ||

        	navigator.webkitGetUserMedia ||

        	navigator.mozGetUserMedia;

        // ask for an audio input

        navigator.getUserMedia(

        {

            "audio": {

                "mandatory": {

                    "googEchoCancellation": "false",

                    "googAutoGainControl": "false",

                    "googNoiseSuppression": "false",

                    "googHighpassFilter": "false"

                },

                "optional": []

            },

        }, gotStream, didntGetStream);

    } catch (e) {

        alert('getUserMedia threw exception :' + e);

    }

}

function didntGetStream() {

    alert('Stream generation failed.');

}

var mediaStreamSource = null;

function gotStream(stream) {

    // Create an AudioNode from the stream.

    mediaStreamSource = audioContext.createMediaStreamSource(stream);

    // Create a new volume meter and connect it.

    meter = createAudioMeter(audioContext);

    mediaStreamSource.connect(meter);

    // kick off the visual updating

    drawLoop();

}

function drawLoop( time ) {

    // clear the background

    canvasContext.clearRect(0,0,WIDTH,HEIGHT);

    // check if we're currently clipping

    if (meter.checkClipping())

        canvasContext.fillStyle = "red";

    else

        canvasContext.fillStyle = "green";

    // draw a bar based on the current volume

    canvasContext.fillRect(0, 0, meter.volume*WIDTH*1.4, HEIGHT);

    // set up the next visual callback

    rafID = window.requestAnimationFrame( drawLoop );

}