import { useLayoutEffect } from "react";
import { gsap } from "gsap";
import { ScrollTrigger } from "gsap/ScrollTrigger";
import { isPageTransitionActive } from "../transitions/PageTransition";

let pluginsRegistered = false;

const registerGsap = () => {
  if (!pluginsRegistered) {
    gsap.registerPlugin(ScrollTrigger);
    pluginsRegistered = true;
  }
};

const createRevealWords = (element) => {
  if (!element) {
    return [];
  }

  if (element.dataset.revealPrepared === "true") {
    return Array.from(element.querySelectorAll(".reveal-word"));
  }

  const originalHtml = element.innerHTML;
  const segments = originalHtml
    .split(/<br\s*\/?>/i)
    .map((segment) => segment.trim())
    .filter(Boolean);

  if (segments.length === 0) {
    return [];
  }

  element.dataset.revealPrepared = "true";
  element.dataset.revealOriginalHtml = originalHtml;
  element.innerHTML = segments
    .map((segment) => {
      const words = segment
        .split(/\s+/)
        .filter(Boolean)
        .map(
          (word) =>
            `<span class="reveal-word-mask"><span class="reveal-word">${word}</span></span>`
        )
        .join(" ");

      return `<span class="reveal-line-mask reveal-word-line">${words}</span>`;
    })
    .join("");

  return Array.from(element.querySelectorAll(".reveal-word"));
};

const restoreRevealWords = (element) => {
  if (!element || element.dataset.revealPrepared !== "true") {
    return;
  }

  const originalHtml = element.dataset.revealOriginalHtml;

  if (originalHtml) {
    element.innerHTML = originalHtml;
  }

  delete element.dataset.revealPrepared;
  delete element.dataset.revealOriginalHtml;
};

function collectRevealItems(scope) {
  const groups = gsap.utils.toArray("[data-reveal-group]", scope);
  return groups.map((group) => ({
    group,
    items: Array.from(group.querySelectorAll("[data-reveal]")).filter(
      (item) => item.closest("[data-reveal-group]") === group
    ),
  }));
}

function hideRevealItems(scope) {
  collectRevealItems(scope).forEach(({ items }) => {
    items.forEach((item) => {
      if (item.dataset.reveal === "lines") {
        gsap.set(item, { autoAlpha: 0 });
      } else {
        gsap.set(item, { y: 36, autoAlpha: 0, force3D: true });
      }
    });
  });
}

function setupReveals(scope) {
  const preparedElements = [];
  const ctx = gsap.context(() => {
    const entries = collectRevealItems(scope);

    entries.forEach(({ group, items }) => {
      if (items.length === 0) {
        return;
      }

      items.forEach((item) => {
        if (item.dataset.reveal === "lines") {
          gsap.set(item, { autoAlpha: 0 });
          return;
        }

        gsap.set(item, {
          y: 36,
          autoAlpha: 0,
          force3D: true,
        });
      });

      ScrollTrigger.create({
        trigger: group,
        start: group.dataset.revealStart || "top 78%",
        once: true,
        onEnter: () => {
          const timeline = gsap.timeline();

          items.forEach((item, index) => {
            const position = index === 0 ? 0 : "<0.16";

            if (item.dataset.reveal === "lines") {
              const words = createRevealWords(item);

              if (words.length === 0) {
                return;
              }

              preparedElements.push(item);
              gsap.set(item, { autoAlpha: 1 });
              gsap.set(words, {
                yPercent: 115,
                rotate: 2.2,
                transformOrigin: "0% 100%",
                force3D: true,
              });

              timeline.to(
                words,
                {
                  yPercent: 0,
                  rotate: 0,
                  duration: 1.08,
                  stagger: 0.065,
                  ease: "power4.out",
                  clearProps: "transform",
                },
                position
              );

              return;
            }

            timeline.to(
              item,
              {
                y: 0,
                autoAlpha: 1,
                duration: 1.02,
                ease: "power4.out",
                clearProps: "transform,opacity,visibility",
              },
              position
            );
          });
        },
      });
    });

    ScrollTrigger.refresh();
  }, scope);

  return { ctx, preparedElements };
}

function useScrollTextReveal(scopeRef, dependencyKey = "") {
  useLayoutEffect(() => {
    const scope = scopeRef.current;

    if (!scope || typeof window === "undefined") {
      return undefined;
    }

    if (window.matchMedia("(prefers-reduced-motion: reduce)").matches) {
      return undefined;
    }

    registerGsap();

    let result = null;
    let handleReady = null;

    if (isPageTransitionActive()) {
      hideRevealItems(scope);
      handleReady = () => {
        result = setupReveals(scope);
      };
      window.addEventListener("page-transition-ready", handleReady, { once: true });
    } else {
      result = setupReveals(scope);
    }

    return () => {
      if (handleReady) {
        window.removeEventListener("page-transition-ready", handleReady);
      }
      if (result) {
        result.ctx.revert();
        result.preparedElements.forEach((element) => restoreRevealWords(element));
      }
    };
  }, [scopeRef, dependencyKey]);
}

export default useScrollTextReveal;