"use client";

import { useEffect } from "react";
import Lenis from "lenis";
import { gsap } from "gsap";
import { ScrollTrigger } from "gsap/ScrollTrigger";

/**
 * Lenis smooth scroll wired into GSAP's ScrollTrigger so scroll-driven
 * animation stays in sync. Disabled entirely under reduced-motion.
 */
export default function SmoothScroll() {
  useEffect(() => {
    const reduce = window.matchMedia("(prefers-reduced-motion: reduce)").matches;
    if (reduce) return;

    gsap.registerPlugin(ScrollTrigger);

    const lenis = new Lenis({
      duration: 1.1,
      easing: (t) => Math.min(1, 1.001 - Math.pow(2, -10 * t)),
      smoothWheel: true,
    });

    lenis.on("scroll", ScrollTrigger.update);

    const raf = (time: number) => lenis.raf(time * 1000);
    gsap.ticker.add(raf);
    gsap.ticker.lagSmoothing(0);

    // anchor links route through Lenis
    const onClick = (e: MouseEvent) => {
      const a = (e.target as HTMLElement)?.closest('a[href^="#"]') as
        | HTMLAnchorElement
        | null;
      if (!a) return;
      const id = a.getAttribute("href");
      if (!id || id === "#") return;
      const el = document.querySelector(id);
      if (!el) return;
      e.preventDefault();
      lenis.scrollTo(el as HTMLElement, { offset: -80 });
    };
    document.addEventListener("click", onClick);

    return () => {
      document.removeEventListener("click", onClick);
      gsap.ticker.remove(raf);
      lenis.destroy();
      ScrollTrigger.getAll().forEach((t) => t.kill());
    };
  }, []);

  return null;
}