Crosshair

import { useEffect, useRef } from 'react';
import { gsap } from 'gsap';

const lerp = (a, b, n) => (1 - n) * a + n * b;

const getMousePos = (e, container) => {
  if (container) {
    const bounds = container.getBoundingClientRect();
    return {
      x: e.clientX - bounds.left,
      y: e.clientY - bounds.top
    };
  }
  return { x: e.clientX, y: e.clientY };
};

const Crosshair = ({ color = 'white', containerRef = null }) => {
  const cursorRef = useRef(null);
  const lineHorizontalRef = useRef(null);
  const lineVerticalRef = useRef(null);
  const filterXRef = useRef(null);
  const filterYRef = useRef(null);

  let mouse = { x: 0, y: 0 };

  useEffect(() => {
    const handleMouseMove = ev => {
      // eslint-disable-next-line react-hooks/exhaustive-deps
      mouse = getMousePos(ev, containerRef?.current);

      if (containerRef?.current) {
        const bounds = containerRef.current.getBoundingClientRect();
        if (
          ev.clientX < bounds.left ||
          ev.clientX > bounds.right ||
          ev.clientY < bounds.top ||
          ev.clientY > bounds.bottom
        ) {
          gsap.to([lineHorizontalRef.current, lineVerticalRef.current], { opacity: 0 });
        } else {
          gsap.to([lineHorizontalRef.current, lineVerticalRef.current], { opacity: 1 });
        }
      }
    };

    const target = containerRef?.current || window;
    target.addEventListener('mousemove', handleMouseMove);

    const renderedStyles = {
      tx: { previous: 0, current: 0, amt: 0.15 },
      ty: { previous: 0, current: 0, amt: 0.15 }
    };

    gsap.set([lineHorizontalRef.current, lineVerticalRef.current], { opacity: 0 });

    const onMouseMove = () => {
      renderedStyles.tx.previous = renderedStyles.tx.current = mouse.x;
      renderedStyles.ty.previous = renderedStyles.ty.current = mouse.y;

      gsap.to([lineHorizontalRef.current, lineVerticalRef.current], {
        duration: 0.9,
        ease: 'Power3.easeOut',
        opacity: 1
      });

      requestAnimationFrame(render);

      target.removeEventListener('mousemove', onMouseMove);
    };

    target.addEventListener('mousemove', onMouseMove);

    const primitiveValues = { turbulence: 0 };

    const tl = gsap
      .timeline({
        paused: true,
        onStart: () => {
          lineHorizontalRef.current.style.filter = `url(#filter-noise-x)`;
          lineVerticalRef.current.style.filter = `url(#filter-noise-y)`;
        },
        onUpdate: () => {
          if (filterXRef.current && filterYRef.current) {
            filterXRef.current.setAttribute('baseFrequency', primitiveValues.turbulence);
            filterYRef.current.setAttribute('baseFrequency', primitiveValues.turbulence);
          }
        },
        onComplete: () => {
          if (lineHorizontalRef.current && lineVerticalRef.current) {
            lineHorizontalRef.current.style.filter = lineVerticalRef.current.style.filter = 'none';
          }
        }
      })
      .to(primitiveValues, {
        duration: 0.5,
        ease: 'power1',
        startAt: { turbulence: 1 },
        turbulence: 0
      });

    const enter = () => tl.restart();
    const leave = () => tl.progress(1).kill();

    const render = () => {
      renderedStyles.tx.current = mouse.x;
      renderedStyles.ty.current = mouse.y;

      for (const key in renderedStyles) {
        renderedStyles[key].previous = lerp(
          renderedStyles[key].previous,
          renderedStyles[key].current,
          renderedStyles[key].amt
        );
      }

      if (lineHorizontalRef.current && lineHorizontalRef.current) {
        gsap.set(lineVerticalRef.current, { x: renderedStyles.tx.previous });
        gsap.set(lineHorizontalRef.current, { y: renderedStyles.ty.previous });
      }

      requestAnimationFrame(render);
    };

    const links = containerRef?.current ? containerRef.current.querySelectorAll('a') : document.querySelectorAll('a');

    links.forEach(link => {
      link.addEventListener('mouseenter', enter);
      link.addEventListener('mouseleave', leave);
    });

    return () => {
      target.removeEventListener('mousemove', handleMouseMove);
      target.removeEventListener('mousemove', onMouseMove);
      links.forEach(link => {
        link.removeEventListener('mouseenter', enter);
        link.removeEventListener('mouseleave', leave);
      });
    };
  }, [containerRef]);

  return (
    <div
      ref={cursorRef}
      className="cursor"
      style={{
        position: containerRef ? 'absolute' : 'fixed',
        top: 0,
        left: 0,
        width: '100%',
        height: '100%',
        pointerEvents: 'none',
        zIndex: 10000
      }}
    >
      <svg style={{ position: 'absolute', left: 0, top: 0, width: '100%', height: '100%' }}>
        <defs>
          <filter id="filter-noise-x">
            <feTurbulence type="fractalNoise" baseFrequency="0.000001" numOctaves="1" ref={filterXRef} />
            <feDisplacementMap in="SourceGraphic" scale="40" />
          </filter>
          <filter id="filter-noise-y">
            <feTurbulence type="fractalNoise" baseFrequency="0.000001" numOctaves="1" ref={filterYRef} />
            <feDisplacementMap in="SourceGraphic" scale="40" />
          </filter>
        </defs>
      </svg>
      <div
        ref={lineHorizontalRef}
        style={{
          position: 'absolute',
          width: '100%',
          height: '1px',
          background: color,
          pointerEvents: 'none',
          transform: 'translateY(50%)',
          opacity: 0
        }}
      ></div>
      <div
        ref={lineVerticalRef}
        style={{
          position: 'absolute',
          height: '100%',
          width: '1px',
          background: color,
          pointerEvents: 'none',
          transform: 'translateX(50%)',
          opacity: 0
        }}
      ></div>
    </div>
  );
};

export default Crosshair;