"use client";

import { useId, useRef, type ElementType, type PointerEvent, type ReactNode } from "react";
import { motion, useMotionValue, useReducedMotion, useSpring, useTransform } from "motion/react";

type HeroSplitProps = {
  title: string;
  /** The picture or video side. Fills a 4:3 panel. */
  media: ReactNode;
  /** Small line above the title. */
  eyebrow?: string;
  subtitle?: string;
  /** Buttons or links under the text. */
  children?: ReactNode;
  /** Small card that floats over the corner of the media. */
  badge?: ReactNode;
  /** Put the media on the left. */
  reverse?: boolean;
  /** h1 by default. Use h2 if the page already has an h1. */
  headingAs?: ElementType;
  /** Set the background and text colour here. */
  className?: string;
};

const EASE = [0.16, 1, 0.3, 1] as const;
const SPRING = { stiffness: 120, damping: 18 };

/* HeroSplit: text on one side, media on the other. The media wipes open, then leans gently toward the pointer. Stacks when narrow. */
export function HeroSplit({
  title,
  media,
  eyebrow,
  subtitle,
  children,
  badge,
  reverse = false,
  headingAs: Heading = "h1",
  className = "bg-[#0b0a14] text-white",
}: HeroSplitProps) {
  const reduce = useReducedMotion();
  const id = useId();
  const panel = useRef<HTMLDivElement>(null);
  const x = useMotionValue(0);
  const y = useMotionValue(0);
  const rotateY = useSpring(useTransform(x, [-0.5, 0.5], [-5, 5]), SPRING);
  const rotateX = useSpring(useTransform(y, [-0.5, 0.5], [4, -4]), SPRING);
  const badgeX = useSpring(useTransform(x, [-0.5, 0.5], [-10, 10]), SPRING);
  const badgeY = useSpring(useTransform(y, [-0.5, 0.5], [-10, 10]), SPRING);

  const move = (e: PointerEvent) => {
    const box = panel.current?.getBoundingClientRect();
    if (reduce || e.pointerType !== "mouse" || !box) return;
    x.set(Math.max(-0.5, Math.min(0.5, (e.clientX - box.left) / box.width - 0.5)));
    y.set(Math.max(-0.5, Math.min(0.5, (e.clientY - box.top) / box.height - 0.5)));
  };
  const leave = () => {
    x.set(0);
    y.set(0);
  };

  const rise = (delay: number) =>
    reduce
      ? { initial: { opacity: 0 }, animate: { opacity: 1 }, transition: { duration: 0.4 } }
      : { initial: { opacity: 0, y: 22 }, animate: { opacity: 1, y: 0 }, transition: { duration: 0.7, delay, ease: EASE } };
  const closed = reverse ? "inset(0 0 0 100% round 20px)" : "inset(0 100% 0 0 round 20px)";

  return (
    <section aria-labelledby={id} onPointerMove={move} onPointerLeave={leave} className={`@container overflow-hidden ${className}`}>
      <div className="mx-auto grid max-w-6xl items-center gap-6 px-5 py-6 @2xl:grid-cols-2 @2xl:gap-12 @2xl:py-20">
        <div className={reverse ? "@2xl:order-2" : ""}>
          {eyebrow && (
            <motion.p {...rise(0)} className="mb-3 text-xs font-medium tracking-[0.2em] uppercase opacity-70 @2xl:text-sm">
              {eyebrow}
            </motion.p>
          )}
          <motion.div {...rise(0.08)}>
            <Heading id={id} className="text-[clamp(1.6rem,8cqw,2.5rem)] leading-[1.06] font-semibold tracking-tight text-balance @2xl:text-[clamp(2rem,5cqw,3.75rem)]">
              {title}
            </Heading>
          </motion.div>
          {subtitle && (
            <motion.p {...rise(0.16)} className="mt-3 max-w-md text-sm text-pretty opacity-70 @2xl:mt-5 @2xl:text-lg">
              {subtitle}
            </motion.p>
          )}
          {children && (
            <motion.div {...rise(0.24)} className="mt-5 flex flex-wrap gap-3 @2xl:mt-8">
              {children}
            </motion.div>
          )}
        </div>

        <div ref={panel} className="relative [perspective:1000px]">
          <motion.div style={reduce ? undefined : { rotateX, rotateY }}>
            <motion.div
              className="aspect-[4/3] overflow-hidden rounded-[20px] [&>*]:size-full [&>*]:object-cover"
              initial={reduce ? { opacity: 0 } : { clipPath: closed }}
              animate={reduce ? { opacity: 1 } : { clipPath: "inset(0 0% 0 0% round 20px)" }}
              transition={reduce ? { duration: 0.4 } : { duration: 1.1, delay: 0.15, ease: EASE }}
            >
              {media}
            </motion.div>
          </motion.div>
          {badge && (
            <motion.div
              className={`absolute bottom-3 @2xl:-bottom-4 ${reverse ? "right-3 @2xl:-right-4" : "left-3 @2xl:-left-4"}`}
              style={reduce ? undefined : { x: badgeX, y: badgeY }}
            >
              <motion.div {...rise(0.9)}>{badge}</motion.div>
            </motion.div>
          )}
        </div>
      </div>
    </section>
  );
}