var retina = window.devicePixelRatio,

// Math shorthands
PI = Math.PI,
sqrt = Math.sqrt,
round = Math.round,
random = Math.random,
cos = Math.cos,
sin = Math.sin,

// Local WindowAnimationTiming interface
rAF = window.requestAnimationFrame,
cAF = window.cancelAnimationFrame || window.cancelRequestAnimationFrame,
_now = Date.now || function () {return new Date().getTime();};

// Local WindowAnimationTiming interface polyfill
(function (w) {
/**
            * Fallback implementation.
            */
var prev = _now();
function fallback(fn) {
var curr = _now();
var ms = Math.max(0, 16 - (curr - prev));
var req = setTimeout(fn, ms);
prev = curr;
return req;
}

/**
            * Cancel.
            */
var cancel = w.cancelAnimationFrame
|| w.webkitCancelAnimationFrame
|| w.clearTimeout;

rAF = w.requestAnimationFrame
|| w.webkitRequestAnimationFrame
|| fallback;

cAF = function(id){
cancel.call(w, id);
};
}(window));

document.addEventListener("DOMContentLoaded", function() {
var speed = 50,
  duration = (1.0 / speed),
  confettiRibbonCount = 11,
  ribbonPaperCount = 30,
  ribbonPaperDist = 8.0,
  ribbonPaperThick = 8.0,
  confettiPaperCount = 95,
  DEG_TO_RAD = PI / 180,
  RAD_TO_DEG = 180 / PI,
  colors = [
    ["#df0049", "#660671"],
    ["#00e857", "#005291"],
    ["#2bebbc", "#05798a"],
    ["#ffd200", "#b06c00"]
  ];

function Vector2(_x, _y) {
this.x = _x, this.y = _y;
this.Length = function() {
  return sqrt(this.SqrLength());
}
this.SqrLength = function() {
  return this.x * this.x + this.y * this.y;
}
this.Add = function(_vec) {
  this.x += _vec.x;
  this.y += _vec.y;
}
this.Sub = function(_vec) {
  this.x -= _vec.x;
  this.y -= _vec.y;
}
this.Div = function(_f) {
  this.x /= _f;
  this.y /= _f;
}
this.Mul = function(_f) {
  this.x *= _f;
  this.y *= _f;
}
this.Normalize = function() {
  var sqrLen = this.SqrLength();
  if (sqrLen != 0) {
    var factor = 1.0 / sqrt(sqrLen);
    this.x *= factor;
    this.y *= factor;
  }
}
this.Normalized = function() {
  var sqrLen = this.SqrLength();
  if (sqrLen != 0) {
    var factor = 1.0 / sqrt(sqrLen);
    return new Vector2(this.x * factor, this.y * factor);
  }
  return new Vector2(0, 0);
}
}
Vector2.Lerp = function(_vec0, _vec1, _t) {
return new Vector2((_vec1.x - _vec0.x) * _t + _vec0.x, (_vec1.y - _vec0.y) * _t + _vec0.y);
}
Vector2.Distance = function(_vec0, _vec1) {
return sqrt(Vector2.SqrDistance(_vec0, _vec1));
}
Vector2.SqrDistance = function(_vec0, _vec1) {
var x = _vec0.x - _vec1.x;
var y = _vec0.y - _vec1.y;
return (x * x + y * y + z * z);
}
Vector2.Scale = function(_vec0, _vec1) {
return new Vector2(_vec0.x * _vec1.x, _vec0.y * _vec1.y);
}
Vector2.Min = function(_vec0, _vec1) {
return new Vector2(Math.min(_vec0.x, _vec1.x), Math.min(_vec0.y, _vec1.y));
}
Vector2.Max = function(_vec0, _vec1) {
return new Vector2(Math.max(_vec0.x, _vec1.x), Math.max(_vec0.y, _vec1.y));
}
Vector2.ClampMagnitude = function(_vec0, _len) {
var vecNorm = _vec0.Normalized;
return new Vector2(vecNorm.x * _len, vecNorm.y * _len);
}
Vector2.Sub = function(_vec0, _vec1) {
return new Vector2(_vec0.x - _vec1.x, _vec0.y - _vec1.y, _vec0.z - _vec1.z);
}

function EulerMass(_x, _y, _mass, _drag) {
this.position = new Vector2(_x, _y);
this.mass = _mass;
this.drag = _drag;
this.force = new Vector2(0, 0);
this.velocity = new Vector2(0, 0);
this.AddForce = function(_f) {
  this.force.Add(_f);
}
this.Integrate = function(_dt) {
  var acc = this.CurrentForce(this.position);
  acc.Div(this.mass);
  var posDelta = new Vector2(this.velocity.x, this.velocity.y);
  posDelta.Mul(_dt);
  this.position.Add(posDelta);
  acc.Mul(_dt);
  this.velocity.Add(acc);
  this.force = new Vector2(0, 0);
}
this.CurrentForce = function(_pos, _vel) {
  var totalForce = new Vector2(this.force.x, this.force.y);
  var speed = this.velocity.Length();
  var dragVel = new Vector2(this.velocity.x, this.velocity.y);
  dragVel.Mul(this.drag * this.mass * speed);
  totalForce.Sub(dragVel);
  return totalForce;
}
}

function ConfettiPaper(_x, _y) {
this.pos = new Vector2(_x, _y);
this.rotationSpeed = (random() * 600 + 800);
this.angle = DEG_TO_RAD * random() * 360;
this.rotation = DEG_TO_RAD * random() * 360;
this.cosA = 1.0;
this.size = 5.0;
this.oscillationSpeed = (random() * 1.5 + 0.5);
this.xSpeed = 40.0;
this.ySpeed = (random() * 60 + 50.0);
this.corners = new Array();
this.time = random();
var ci = round(random() * (colors.length - 1));
this.frontColor = colors[ci][0];
this.backColor = colors[ci][1];
for (var i = 0; i < 4; i++) {
  var dx = cos(this.angle + DEG_TO_RAD * (i * 90 + 45));
  var dy = sin(this.angle + DEG_TO_RAD * (i * 90 + 45));
  this.corners[i] = new Vector2(dx, dy);
}
this.Update = function(_dt) {
  this.time += _dt;
  this.rotation += this.rotationSpeed * _dt;
  this.cosA = cos(DEG_TO_RAD * this.rotation);
  this.pos.x += cos(this.time * this.oscillationSpeed) * this.xSpeed * _dt
  this.pos.y += this.ySpeed * _dt;
  if (this.pos.y > ConfettiPaper.bounds.y) {
    this.pos.x = random() * ConfettiPaper.bounds.x;
    this.pos.y = 0;
  }
}
this.Draw = function(_g) {
  if (this.cosA > 0) {
    _g.fillStyle = this.frontColor;
  } else {
    _g.fillStyle = this.backColor;
  }
  _g.beginPath();
  _g.moveTo((this.pos.x + this.corners[0].x * this.size) * retina, (this.pos.y + this.corners[0].y * this.size * this.cosA) * retina);
  for (var i = 1; i < 4; i++) {
    _g.lineTo((this.pos.x + this.corners[i].x * this.size) * retina, (this.pos.y + this.corners[i].y * this.size * this.cosA) * retina);
  }
  _g.closePath();
  _g.fill();
}
}
ConfettiPaper.bounds = new Vector2(0, 0);

function ConfettiRibbon(_x, _y, _count, _dist, _thickness, _angle, _mass, _drag) {
this.particleDist = _dist;
this.particleCount = _count;
this.particleMass = _mass;
this.particleDrag = _drag;
this.particles = new Array();
var ci = round(random() * (colors.length - 1));
this.frontColor = colors[ci][0];
this.backColor = colors[ci][1];
this.xOff = (cos(DEG_TO_RAD * _angle) * _thickness);
this.yOff = (sin(DEG_TO_RAD * _angle) * _thickness);
this.position = new Vector2(_x, _y);
this.prevPosition = new Vector2(_x, _y);
this.velocityInherit = (random() * 2 + 4);
this.time = random() * 100;
this.oscillationSpeed = (random() * 2 + 2);
this.oscillationDistance = (random() * 40 + 40);
this.ySpeed = (random() * 40 + 80);
for (var i = 0; i < this.particleCount; i++) {
  this.particles[i] = new EulerMass(_x, _y - i * this.particleDist, this.particleMass, this.particleDrag);
}
this.Update = function(_dt) {
  var i = 0;
  this.time += _dt * this.oscillationSpeed;
  this.position.y += this.ySpeed * _dt;
  this.position.x += cos(this.time) * this.oscillationDistance * _dt;
  this.particles[0].position = this.position;
  var dX = this.prevPosition.x - this.position.x;
  var dY = this.prevPosition.y - this.position.y;
  var delta = sqrt(dX * dX + dY * dY);
  this.prevPosition = new Vector2(this.position.x, this.position.y);
  for (i = 1; i < this.particleCount; i++) {
    var dirP = Vector2.Sub(this.particles[i - 1].position, this.particles[i].position);
    dirP.Normalize();
    dirP.Mul((delta / _dt) * this.velocityInherit);
    this.particles[i].AddForce(dirP);
  }
  for (i = 1; i < this.particleCount; i++) {
    this.particles[i].Integrate(_dt);
  }
  for (i = 1; i < this.particleCount; i++) {
    var rp2 = new Vector2(this.particles[i].position.x, this.particles[i].position.y);
    rp2.Sub(this.particles[i - 1].position);
    rp2.Normalize();
    rp2.Mul(this.particleDist);
    rp2.Add(this.particles[i - 1].position);
    this.particles[i].position = rp2;
  }
  if (this.position.y > ConfettiRibbon.bounds.y + this.particleDist * this.particleCount) {
    this.Reset();
  }
}
this.Reset = function() {
  this.position.y = -random() * ConfettiRibbon.bounds.y;
  this.position.x = random() * ConfettiRibbon.bounds.x;
  this.prevPosition = new Vector2(this.position.x, this.position.y);
  this.velocityInherit = random() * 2 + 4;
  this.time = random() * 100;
  this.oscillationSpeed = random() * 2.0 + 1.5;
  this.oscillationDistance = (random() * 40 + 40);
  this.ySpeed = random() * 40 + 80;
  var ci = round(random() * (colors.length - 1));
  this.frontColor = colors[ci][0];
  this.backColor = colors[ci][1];
  this.particles = new Array();
  for (var i = 0; i < this.particleCount; i++) {
    this.particles[i] = new EulerMass(this.position.x, this.position.y - i * this.particleDist, this.particleMass, this.particleDrag);
  }
}
this.Draw = function(_g) {
  for (var i = 0; i < this.particleCount - 1; i++) {
    var p0 = new Vector2(this.particles[i].position.x + this.xOff, this.particles[i].position.y + this.yOff);
    var p1 = new Vector2(this.particles[i + 1].position.x + this.xOff, this.particles[i + 1].position.y + this.yOff);
    if (this.Side(this.particles[i].position.x, this.particles[i].position.y, this.particles[i + 1].position.x, this.particles[i + 1].position.y, p1.x, p1.y) < 0) {
      _g.fillStyle = this.frontColor;
      _g.strokeStyle = this.frontColor;
    } else {
      _g.fillStyle = this.backColor;
      _g.strokeStyle = this.backColor;
    }
    if (i == 0) {
      _g.beginPath();
      _g.moveTo(this.particles[i].position.x * retina, this.particles[i].position.y * retina);
      _g.lineTo(this.particles[i + 1].position.x * retina, this.particles[i + 1].position.y * retina);
      _g.lineTo(((this.particles[i + 1].position.x + p1.x) * 0.5) * retina, ((this.particles[i + 1].position.y + p1.y) * 0.5) * retina);
      _g.closePath();
      _g.stroke();
      _g.fill();
      _g.beginPath();
      _g.moveTo(p1.x * retina, p1.y * retina);
      _g.lineTo(p0.x * retina, p0.y * retina);
      _g.lineTo(((this.particles[i + 1].position.x + p1.x) * 0.5) * retina, ((this.particles[i + 1].position.y + p1.y) * 0.5) * retina);
      _g.closePath();
      _g.stroke();
      _g.fill();
    } else if (i == this.particleCount - 2) {
      _g.beginPath();
      _g.moveTo(this.particles[i].position.x * retina, this.particles[i].position.y * retina);
      _g.lineTo(this.particles[i + 1].position.x * retina, this.particles[i + 1].position.y * retina);
      _g.lineTo(((this.particles[i].position.x + p0.x) * 0.5) * retina, ((this.particles[i].position.y + p0.y) * 0.5) * retina);
      _g.closePath();
      _g.stroke();
      _g.fill();
      _g.beginPath();
      _g.moveTo(p1.x * retina, p1.y * retina);
      _g.lineTo(p0.x * retina, p0.y * retina);
      _g.lineTo(((this.particles[i].position.x + p0.x) * 0.5) * retina, ((this.particles[i].position.y + p0.y) * 0.5) * retina);
      _g.closePath();
      _g.stroke();
      _g.fill();
    } else {
      _g.beginPath();
      _g.moveTo(this.particles[i].position.x * retina, this.particles[i].position.y * retina);
      _g.lineTo(this.particles[i + 1].position.x * retina, this.particles[i + 1].position.y * retina);
      _g.lineTo(p1.x * retina, p1.y * retina);
      _g.lineTo(p0.x * retina, p0.y * retina);
      _g.closePath();
      _g.stroke();
      _g.fill();
    }
  }
}
this.Side = function(x1, y1, x2, y2, x3, y3) {
  return ((x1 - x2) * (y3 - y2) - (y1 - y2) * (x3 - x2));
}
}
ConfettiRibbon.bounds = new Vector2(0, 0);
confetti = {};
confetti.Context = function(id) {
var i = 0;
var canvas = document.getElementById(id);
var canvasParent = canvas.parentNode;
var canvasWidth = canvasParent.offsetWidth;
var canvasHeight = canvasParent.offsetHeight;
canvas.width = canvasWidth * retina;
canvas.height = canvasHeight * retina;
var context = canvas.getContext('2d');
var interval = null;
var confettiRibbons = new Array();
ConfettiRibbon.bounds = new Vector2(canvasWidth, canvasHeight);
for (i = 0; i < confettiRibbonCount; i++) {
  confettiRibbons[i] = new ConfettiRibbon(random() * canvasWidth, -random() * canvasHeight * 2, ribbonPaperCount, ribbonPaperDist, ribbonPaperThick, 45, 1, 0.05);
}
var confettiPapers = new Array();
ConfettiPaper.bounds = new Vector2(canvasWidth, canvasHeight);
for (i = 0; i < confettiPaperCount; i++) {
  confettiPapers[i] = new ConfettiPaper(random() * canvasWidth, random() * canvasHeight);
}
this.resize = function() {
  canvasWidth = canvasParent.offsetWidth;
  canvasHeight = canvasParent.offsetHeight;
  canvas.width = canvasWidth * retina;
  canvas.height = canvasHeight * retina;
  ConfettiPaper.bounds = new Vector2(canvasWidth, canvasHeight);
  ConfettiRibbon.bounds = new Vector2(canvasWidth, canvasHeight);
}
this.start = function() {
  this.stop()
  var context = this;
  this.update();
}
this.stop = function() {
  cAF(this.interval);
}
this.update = function() {
  var i = 0;
  context.clearRect(0, 0, canvas.width, canvas.height);
  for (i = 0; i < confettiPaperCount; i++) {
    confettiPapers[i].Update(duration);
    confettiPapers[i].Draw(context);
  }
  for (i = 0; i < confettiRibbonCount; i++) {
    confettiRibbons[i].Update(duration);
    confettiRibbons[i].Draw(context);
  }
  this.interval = rAF(function() {
    confetti.update();
  });
}
}
var confetti = new confetti.Context('confetti');
confetti.start();
window.addEventListener('resize', function(event){
confetti.resize();
});
});