var stage;
var circlesLayer;
var circles;
var stats;
var width = 500;
var height = 300;

var VERSION = Konva.version === 'dev' ? 'new' : 'old';

window.requestAnimFrame = (function () {
  return (
    window.requestAnimationFrame ||
    window.webkitRequestAnimationFrame ||
    window.mozRequestAnimationFrame ||
    window.oRequestAnimationFrame ||
    window.msRequestAnimationFrame ||
    function (callback) {
      window.setTimeout(callback, 1000 / 30);
    }
  );
})();

function fpsCounter() {
  //fps stat---------------------------
  stats = new Stats();
  stats.setMode(0);
  stats.domElement.style.position = 'fixed';
  stats.domElement.style.left = '0px';
  stats.domElement.style.top = '0px';
  $('html').append(stats.domElement);
}

$(function () {
  fpsCounter();

  make_stage();

  var colors = ['red', 'orange', 'yellow', 'green', 'blue', 'cyan', 'purple'];
  var colorIndex = 0;

  circles = [];
  for (var n = 0; n < 2500; n++) {
    (function () {
      var color = colors[colorIndex++];
      if (colorIndex >= colors.length) {
        colorIndex = 0;
      }

      var shape = make_shape(color);
      circlesLayer.add(shape);
      circles.push(shape);
    })();
  }

  stage.add(circlesLayer);
  animate(new Date().getTime());
});

function animate(lastTime) {
  stats.begin();
  // update
  var date = new Date();
  var time = date.getTime();
  var timeDiff = time - lastTime;
  var period = timeDiff / 1000; //times per second, our period

  for (var i = 0; i < circles.length; i++) {
    var x = Math.round(Math.random() * width);
    var y = Math.round(Math.random() * height);

    circles[i].setPosition({ x: x, y: y });
  }
  lastTime = time;

  circlesLayer.draw();
  stats.end();
  requestAnimFrame(function () {
    animate(lastTime);
  });
}

function make_shape(color) {
  return new Konva.Rect({
    fillLinearGradientStartPoint: { x: -50, y: -50 },
    fillLinearGradientEndPoint: { x: 50, y: 50 },
    fillLinearGradientColorStops: [0, 'black', 1, color],
    // fill: color,
    width: 10,
    height: 10,
  });
}

function make_stage() {
  stage = new Konva.Stage({
    container: 'container',
    width: width,
    height: height,
  });

  // circlesLayer = new Konva.FastLayer();
  circlesLayer = new Konva.Layer({
    listening: false,
  });
}