function normalizeWheel(/*object*/ event) /*object*/ {
  var PIXEL_STEP = 10;
var LINE_HEIGHT = 40;
var PAGE_HEIGHT = 800;
  var sX = 0,
    sY = 0, // spinX, spinY
    pX = 0,
    pY = 0; // pixelX, pixelY

  // Legacy
  if ("detail" in event) {
    sY = event.detail;
  }
  if ("wheelDelta" in event) {
    sY = -event.wheelDelta / 120;
  }
  if ("wheelDeltaY" in event) {
    sY = -event.wheelDeltaY / 120;
  }
  if ("wheelDeltaX" in event) {
    sX = -event.wheelDeltaX / 120;
  }

  // side scrolling on FF with DOMMouseScroll
  if ("axis" in event && event.axis === event.HORIZONTAL_AXIS) {
    sX = sY;
    sY = 0;
  }

  pX = sX * PIXEL_STEP;
  pY = sY * PIXEL_STEP;

  if ("deltaY" in event) {
    pY = event.deltaY;
  }
  if ("deltaX" in event) {
    pX = event.deltaX;
  }

  if ((pX || pY) && event.deltaMode) {
    if (event.deltaMode === 1) {
      // delta in LINE units
      pX *= LINE_HEIGHT;
      pY *= LINE_HEIGHT;
    } else {
      // delta in PAGE units
      pX *= PAGE_HEIGHT;
      pY *= PAGE_HEIGHT;
    }
  }

  // Fall-back if spin cannot be determined
  if (pX && !sX) {
    sX = pX < 1 ? -1 : 1;
  }
  if (pY && !sY) {
    sY = pY < 1 ? -1 : 1;
  }

  return {
    spinX: sX,
    spinY: sY,
    pixelX: pX,
    pixelY: pY
  };
}

const getHeight = () => {
  var body = document.body,
    html = document.documentElement;

  var height = Math.max(
    body.scrollHeight,
    body.offsetHeight,
    html.clientHeight,
    html.scrollHeight,
    html.offsetHeight
  );
  return height;
};
let t1 = TweenLite;
let curScroll = 0;
const lineHeight = 150;
let fullHeight = getHeight();
let mainH = $(".main").height();
let wH = window.innerHeight;
let width = $(window).width();
let isScrolling = false;
let lastScroll = 0;
let lastTime = 0;
let topp = (wH - lineHeight) / 2;
let factor =  $(window).height()/ lineHeight;
let windowHeight = $(window).height();
let maxScroll = (fullHeight - windowHeight)/factor;
let clip = `rect(${topp}px,${width}px,${topp + lineHeight}px,0)`
$(".nav ul").css("top", `${topp}px`);
$(".nav__2").css('clip',clip)

//     clip: rect(298px,1000px,471px,0);
// }
document.addEventListener("wheel", function(e) {
  if (!isScrolling) isScrolling = true;
  const norm = normalizeWheel(e);
  curScroll += norm.spinY * 50;
  if (curScroll > maxScroll) curScroll = maxScroll;
  if (curScroll <= 0) curScroll = 0;
  t1.to(".main", 0.5, {
    y: -curScroll*factor,
    overflow: 5,
    onUpdate: e => {
      TweenLite.to('.nav ul',.2,{
        y:-curScroll,
        overflow:5
      })
    },
    onComplete: e => {
      isScrolling = false;
      goToClosest();
    }
  });
});




function goToClosest(){
  const closest = Math.round((curScroll / lineHeight));
  goTo(closest);
}


function goTo(n){
  curScroll = n*lineHeight;
   t1.to(".main", 0.5, {
    y: -curScroll*factor,
    overflow: 5,
    onComplete: e => {
      isScrolling = false;
    }
  });
  
}
function Velocity(e) {
  if (isScrolling) {
    let speed = (curScroll - lastScroll) / (e - lastTime);
    if (speed < -5) speed = -5;
    if (speed > 5) speed = 5;
    TweenLite.to("li", 1, {
      skewY: -speed * 20
    });
    lastScroll = curScroll;
    lastTime = e;
  }
  window.requestAnimationFrame(Velocity);
}

Velocity();