"use client";

import { useEffect, useRef, useState } from "react";
import { gsap } from "gsap";

interface PageTransitionProps {
  isOpen: boolean;
  onComplete?: () => void;
  direction?: "reveal" | "unreveal";
}

/* ------------------------------------------------------------------
   1. Path data – identical to the original demo
   ------------------------------------------------------------------ */
const paths = {
  step1: {
    unfilled: "M 0 100 V 100 Q 50 100 100 100 V 100 z",
    inBetween: {
      curve1: "M 0 100 V 50 Q 50 0 100 50 V 100 z",
      curve2: "M 0 100 V 50 Q 50 100 100 50 V 100 z",
    },
    filled: "M 0 100 V 0 Q 50 0 100 0 V 100 z",
  },
  step2: {
    filled: "M 0 0 V 100 Q 50 100 100 100 V 0 z",
    inBetween: {
      curve1: "M 0 0 V 50 Q 50 0 100 50 V 0 z",
      curve2: "M 0 0 V 50 Q 50 100 100 50 V 0 z",
    },
    unfilled: "M 0 0 V 0 Q 50 0 100 0 V 0 z",
  },
};

export const PageTransition = ({
  isOpen,
  onComplete,
  direction = "reveal",
}: PageTransitionProps) => {
  const pathRef = useRef<SVGPathElement>(null);
  const svgRef = useRef<SVGSVGElement>(null); // 👈 new ref for hiding
  const [animating, setAnimating] = useState(false);

  /* --------------------------------------------------------------
     REVEAL – open second view
   -------------------------------------------------------------- */
  const reveal = () => {
    if (animating) return;
    setAnimating(true);

    // 👇 Show overlay before animation starts
    gsap.set(svgRef.current, { display: "block" });

    const tl = gsap.timeline({
      onComplete: () => {
        setAnimating(false);
        onComplete?.();
        // 👇 Hide overlay after animation completes
        gsap.set(svgRef.current, { display: "none" });
      },
    });

    tl.set(pathRef.current, { attr: { d: paths.step1.unfilled } })
      .to(pathRef.current, {
        duration: 0.8,
        ease: "power4.in",
        attr: { d: paths.step1.inBetween.curve1 },
      })
      .to(pathRef.current, {
        duration: 0.2,
        ease: "power1",
        attr: { d: paths.step1.filled },
        onComplete: () => onComplete?.(),
      })
      .set(pathRef.current, { attr: { d: paths.step2.filled } })
      .to(pathRef.current, {
        duration: 0.2,
        ease: "sine.in",
        attr: { d: paths.step2.inBetween.curve1 },
      })
      .to(pathRef.current, {
        duration: 1,
        ease: "power4",
        attr: { d: paths.step2.unfilled },
      });
  };

  /* --------------------------------------------------------------
     UNREVEAL – back to first view
   -------------------------------------------------------------- */
  const unreveal = () => {
    if (animating) return;
    setAnimating(true);

    // 👇 Show overlay before animation starts
    gsap.set(svgRef.current, { display: "block" });

    const tl = gsap.timeline({
      onComplete: () => {
        setAnimating(false);
        onComplete?.();
        // 👇 Hide overlay after animation completes
        gsap.set(svgRef.current, { display: "none" });
      },
    });

    tl.set(pathRef.current, { attr: { d: paths.step2.unfilled } })
      .to(pathRef.current, {
        duration: 0.8,
        ease: "power4.in",
        attr: { d: paths.step2.inBetween.curve2 },
      })
      .to(pathRef.current, {
        duration: 0.2,
        ease: "power1",
        attr: { d: paths.step2.filled },
        onComplete: () => onComplete?.(),
      })
      .set(pathRef.current, { attr: { d: paths.step1.filled } })
      .to(pathRef.current, {
        duration: 0.2,
        ease: "sine.in",
        attr: { d: paths.step1.inBetween.curve2 },
      })
      .to(pathRef.current, {
        duration: 1,
        ease: "power4",
        attr: { d: paths.step1.unfilled },
      });
  };

  /* --------------------------------------------------------------
     React to prop changes
   -------------------------------------------------------------- */
  useEffect(() => {
    if (!isOpen) return;
    if (direction === "reveal") reveal();
    else if (direction === "unreveal") unreveal();
  }, [isOpen, direction]);

  return (
    <svg
      ref={svgRef}
      className="pointer-events-none fixed top-0 left-0 z-[9999] h-screen w-screen"
      viewBox="0 0 100 100"
      preserveAspectRatio="none"
      style={{ display: "none" }} // 👈 hidden by default
    >
      <path
        ref={pathRef}
        className="overlay__path"
        d="M 0 100 V 100 Q 50 100 100 100 V 100 z"
        vectorEffect="non-scaling-stroke"
        fill="#274b2d"
      />
    </svg>
  );
};