"use client";

import { useEffect, useRef } from "react";
import { gsap } from "gsap";
import { ScrollTrigger } from "gsap/ScrollTrigger";

type SplitTextProps = {
  text: string;
  className?: string;
  delay?: number;
  duration?: number;
  ease?: string;
  splitType?: "chars" | "words" | "lines" | "chars,words" | "words,lines" | "chars,words,lines";
  from?: gsap.TweenVars;
  to?: gsap.TweenVars;
  threshold?: number;
  rootMargin?: string;
  textAlign?: "left" | "center" | "right";
  tag?: "p" | "h1" | "h2" | "h3" | "span";
  onLetterAnimationComplete?: () => void;
  showCallback?: boolean;
};

export default function SplitText({
  text = "",
  className = "",
  delay = 50,
  duration = 1.25,
  ease = "power3.out",
  splitType = "chars",
  from = { opacity: 0, y: 40 },
  to = { opacity: 1, y: 0 },
  threshold = 0.1,
  rootMargin = "-100px",
  textAlign = "center",
  tag = "p",
  onLetterAnimationComplete,
  showCallback = false,
}: SplitTextProps) {
  const ref = useRef<HTMLElement | null>(null);
  const animationCompletedRef = useRef(false);
  const onCompleteRef = useRef(onLetterAnimationComplete);

  useEffect(() => {
    onCompleteRef.current = onLetterAnimationComplete;
  }, [onLetterAnimationComplete]);

  useEffect(() => {
    if (typeof window === "undefined" || !ref.current || !text) return;
    if (animationCompletedRef.current) return;

    gsap.registerPlugin(ScrollTrigger);

    const el = ref.current;
    const reduceMotion = window.matchMedia("(prefers-reduced-motion: reduce)").matches;

    if (reduceMotion) {
      animationCompletedRef.current = true;
      onCompleteRef.current?.();
      return;
    }

    const startPct = (1 - threshold) * 100;
    const marginMatch = /^(-?\d+(?:\.\d+)?)(px|em|rem|%)?$/.exec(rootMargin);
    const marginValue = marginMatch ? parseFloat(marginMatch[1]) : 0;
    const marginUnit = marginMatch ? marginMatch[2] || "px" : "px";
    const sign =
      marginValue === 0
        ? ""
        : marginValue < 0
          ? `-=${Math.abs(marginValue)}${marginUnit}`
          : `+=${marginValue}${marginUnit}`;
    const start = `top ${startPct}%${sign}`;

    // Select targets based on splitType
    let targets: Element[] = [];
    if (splitType.includes("chars")) {
      targets = Array.from(el.querySelectorAll(".split-char"));
    } else if (splitType.includes("words")) {
      targets = Array.from(el.querySelectorAll(".split-word"));
    } else {
      targets = [el];
    }

    // Set initial state
    gsap.set(targets, { ...from });

    // Animate using scrollTrigger
    const anim = gsap.to(targets, {
      ...to,
      duration,
      ease,
      stagger: delay / 1000,
      scrollTrigger: {
        trigger: el,
        start,
        once: true,
        fastScrollEnd: true,
        anticipatePin: 0.4,
      },
      onComplete: () => {
        animationCompletedRef.current = true;
        onCompleteRef.current?.();
      },
      force3D: true,
    });

    return () => {
      ScrollTrigger.getAll().forEach((trigger) => {
        if (trigger.trigger === el) trigger.kill();
      });
      anim.kill();
    };
  }, [
    delay,
    duration,
    ease,
    from,
    rootMargin,
    showCallback,
    splitType,
    text,
    threshold,
    to,
  ]);

  const Tag = tag;
  const words = text.split(" ");

  return (
    <Tag
      ref={(node) => {
        ref.current = node;
      }}
      className={`split-parent ${className}`.trim()}
      style={{
        textAlign,
        overflow: "hidden",
        display: "inline-block",
        whiteSpace: "normal",
        wordWrap: "break-word",
        willChange: "transform, opacity",
      }}
    >
      {splitType.includes("chars") ? (
        words.map((word, wIdx) => (
          <span key={wIdx} className="split-word inline-block" style={{ whiteSpace: "nowrap" }}>
            {word.split("").map((char, cIdx) => (
              <span key={cIdx} className="split-char inline-block" style={{ display: "inline-block" }}>
                {char}
              </span>
            ))}
            {wIdx < words.length - 1 ? "\u00A0" : ""}
          </span>
        ))
      ) : splitType.includes("words") ? (
        words.map((word, wIdx) => (
          <span key={wIdx} className="split-word inline-block" style={{ display: "inline-block" }}>
            {word}
            {wIdx < words.length - 1 ? "\u00A0" : ""}
          </span>
        ))
      ) : (
        text
      )}
    </Tag>
  );
}