"use client";

import { Fragment, useId, type CSSProperties, type ElementType, type ReactNode } from "react";
import { motion, useReducedMotion } from "motion/react";

type HeroNovaProps = {
  title: string;
  /** Small line above the title. */
  eyebrow?: string;
  subtitle?: string;
  /** Buttons or links under the text. */
  children?: ReactNode;
  /** Colours of the burst, from core to rim. */
  colors?: [string, string, string];
  /** h1 by default. Use h2 if the page already has an h1. */
  headingAs?: ElementType;
  /** Set the height, background and text colour here. */
  className?: string;
};

const EASE = [0.16, 1, 0.3, 1] as const;

// A circle of n% of the section width, centred on its parent. Never too small on a phone.
const disc = (n: number): CSSProperties => {
  const size = `max(${n}cqw, ${n * 7}px)`;
  return { width: size, height: size, left: `calc(${size} / -2)`, top: `calc(${size} / -2)` };
};

/* HeroNova: a centred hero. A star bursts behind the title, throws a shock ring, then settles into a slow glow while the words rise in. */
export function HeroNova({
  title,
  eyebrow,
  subtitle,
  children,
  colors = ["#ffffff", "#a78bfa", "#22d3ee"],
  headingAs: Heading = "h1",
  className = "min-h-[36rem] bg-[#07060f] text-white",
}: HeroNovaProps) {
  const reduce = useReducedMotion();
  const id = useId();
  const [core, mid, rim] = colors;
  const words = title.split(" ");

  const rise = (delay: number) =>
    reduce
      ? { initial: { opacity: 0 }, animate: { opacity: 1 }, transition: { duration: 0.4 } }
      : { initial: { opacity: 0, y: 24 }, animate: { opacity: 1, y: 0 }, transition: { duration: 0.8, delay, ease: EASE } };

  return (
    <section aria-labelledby={id} className={`@container relative isolate grid place-items-center overflow-hidden ${className}`}>
      <div aria-hidden className="absolute top-1/2 left-1/2 -z-10 size-0">
        <motion.div
          className="absolute rounded-full"
          style={{ ...disc(120), background: `radial-gradient(closest-side, ${mid}55, ${rim}22 45%, transparent 72%)` }}
          initial={reduce ? false : { scale: 0.1, opacity: 0 }}
          animate={{ scale: 1, opacity: 0.85 }}
          transition={{ duration: 1.6, ease: EASE }}
        />
        <motion.div
          className="absolute rounded-full mix-blend-screen"
          style={{
            ...disc(84),
            background: `repeating-conic-gradient(from 0deg, ${mid}38 0deg 3deg, transparent 3deg 11deg, ${rim}2e 11deg 13deg, transparent 13deg 23deg)`,
            maskImage: "radial-gradient(closest-side, black 8%, transparent 78%)",
            WebkitMaskImage: "radial-gradient(closest-side, black 8%, transparent 78%)",
          }}
          initial={reduce ? false : { scale: 0.2, opacity: 0 }}
          animate={reduce ? undefined : { scale: 1, opacity: 1, rotate: 360 }}
          transition={{
            scale: { duration: 1.6, ease: EASE },
            opacity: { duration: 1 },
            rotate: { duration: 120, ease: "linear", repeat: Infinity },
          }}
        />
        <motion.div
          className="absolute rounded-full border"
          style={{ ...disc(60), borderColor: rim }}
          initial={{ scale: 0.05, opacity: reduce ? 0 : 0.9 }}
          animate={{ scale: 1.5, opacity: 0 }}
          transition={{ duration: 1.6, ease: "easeOut" }}
        />
        <motion.div
          className="absolute rounded-full blur-2xl"
          style={{ ...disc(18), background: `radial-gradient(closest-side, ${core}, ${mid} 40%, transparent)` }}
          initial={reduce ? { opacity: 0.45 } : { scale: 3, opacity: 1 }}
          animate={reduce ? undefined : { scale: 1, opacity: 0.55 }}
          transition={{ duration: 1.4, ease: EASE }}
        />
      </div>

      <div className="flex max-w-3xl flex-col items-center px-5 py-6 text-center @2xl:py-24">
        {eyebrow && (
          <motion.p {...rise(0.3)} className="mb-3 text-xs font-medium tracking-[0.2em] uppercase opacity-70 @2xl:mb-5 @2xl:text-sm">
            {eyebrow}
          </motion.p>
        )}
        <Heading id={id} className="text-[clamp(1.75rem,9cqw,4.5rem)] leading-[1.05] font-semibold tracking-tight text-balance">
          <span className="sr-only">{title}</span>
          <span aria-hidden>
            {words.map((word, i) => (
              <Fragment key={i}>
                <motion.span {...rise(0.35 + i * 0.07)} className="inline-block">
                  {word}
                </motion.span>{" "}
              </Fragment>
            ))}
          </span>
        </Heading>
        {subtitle && (
          <motion.p {...rise(0.7)} className="mt-3 max-w-xl text-sm text-pretty opacity-70 @2xl:mt-5 @2xl:text-lg">
            {subtitle}
          </motion.p>
        )}
        {children && (
          <motion.div {...rise(0.85)} className="mt-5 flex flex-wrap justify-center gap-3 @2xl:mt-8">
            {children}
          </motion.div>
        )}
      </div>
    </section>
  );
}