"use client";

import { useRef, useState, type PointerEvent } from "react";
import { animate, motion, useAnimationFrame, useInView, useMotionTemplate, useMotionValue, useReducedMotion, useSpring, useTransform } from "motion/react";

type PolaroidDevelopProps = {
  src: string;
  alt: string;
  /** Written on the white strip. */
  caption?: string;
  /** Seconds to develop on its own. */
  duration?: number;
  /** How much each shake speeds it up. 0 turns shaking off. */
  shake?: number;
  /** Resting tilt, in degrees. */
  tilt?: number;
  className?: string;
};

/* PolaroidDevelop: an instant photo that comes out blank and develops on its own. Shake it and it goes faster. Press it when done for a new shot. */
export function PolaroidDevelop({ src, alt, caption, duration = 9, shake = 1, tilt = -2, className = "" }: PolaroidDevelopProps) {
  const reduce = useReducedMotion();
  const box = useRef<HTMLDivElement>(null);
  const seen = useInView(box, { amount: 0.4 });
  const [done, setDone] = useState(false);
  const p = useMotionValue(0);
  const flash = useMotionValue(0);
  const push = useMotionValue(0);
  const lean = useSpring(push, { stiffness: 320, damping: 11 });
  const rotate = useTransform(lean, (v) => tilt + v);
  const lastDir = useRef(0);

  const saturate = useTransform(p, [0.1, 1], [0.15, 1.04]);
  const contrast = useTransform(p, [0, 0.55, 1], [0.5, 0.82, 1.03]);
  const bright = useTransform(p, [0, 0.45, 1], [1.15, 0.95, 1]);
  const warm = useTransform(p, [0.2, 0.6, 1], [0, 0.38, 0.06]);
  const filter = useMotionTemplate`saturate(${saturate}) contrast(${contrast}) brightness(${bright}) sepia(${warm})`;
  const milk = useTransform(p, [0, 0.72], [1, 0]);
  const reach = useTransform(p, [0, 0.72], [-30, 110]);
  const edge = useTransform(reach, (r) => r + 46);
  const mask = useMotionTemplate`radial-gradient(circle at 46% 42%, transparent ${reach}%, #000 ${edge}%)`;

  useAnimationFrame((_, dt) => {
    if (push.get() !== 0) push.set(Math.abs(push.get()) < 0.05 ? 0 : push.get() * 0.9);
    if (!seen || done) return;
    const next = reduce ? 1 : Math.min(1, p.get() + dt / (duration * 1000));
    p.set(next);
    if (next === 1) setDone(true);
  });

  function hurry(by: number) {
    if (done) return;
    const next = Math.min(1, p.get() + by);
    p.set(next);
    if (next === 1) setDone(true);
  }

  function move(e: PointerEvent<HTMLButtonElement>) {
    if (reduce || !shake) return;
    const dx = e.movementX;
    if (Math.abs(dx) < 2) return;
    push.set(Math.max(-9, Math.min(9, push.get() + dx * 0.5)));
    const dir = Math.sign(dx);
    if (dir !== lastDir.current) hurry(0.022 * shake);
    lastDir.current = dir;
  }

  function press() {
    if (done) {
      p.set(0);
      setDone(false);
      if (!reduce) animate(flash, [1, 0], { duration: 0.6, ease: "easeOut" });
      return;
    }
    if (reduce || !shake) return;
    push.set(push.get() > 0 ? -8 : 8);
    hurry(0.14 * shake);
  }

  return (
    <div ref={box} className={`@container w-72 ${className}`}>
      <motion.button
        type="button"
        onPointerMove={move}
        onClick={press}
        aria-label={done ? `${alt}. Take a new shot` : `Photo still developing: ${alt}. Shake it`}
        style={{ rotate }}
        className="block w-full touch-pan-y bg-[#f5f2ea] p-[1.05em] pb-0 text-[5cqw] shadow-[0_0.1em_0.2em_rgba(0,0,0,0.3),0_1.1em_1.7em_-0.5em_rgba(0,0,0,0.6)]"
      >
        <span className="relative block aspect-[1/1.02] overflow-hidden bg-[#2a2c27] shadow-[inset_0_0_0.2em_rgba(0,0,0,0.5)]">
          <motion.img src={src} alt="" draggable={false} className="absolute inset-0 h-full w-full object-cover" style={{ filter }} />
          <motion.span aria-hidden className="absolute inset-0 bg-[linear-gradient(150deg,#d4d8cb,#b9c2b3_60%,#a9b3a6)]" style={{ opacity: milk, maskImage: mask, WebkitMaskImage: mask }} />
          <span aria-hidden className="absolute inset-0 bg-[linear-gradient(125deg,rgba(255,255,255,0.2),transparent_34%)]" />
          <motion.span aria-hidden className="absolute inset-0 bg-white" style={{ opacity: flash }} />
        </span>
        <span className="flex h-[3.5em] items-center justify-center truncate px-[0.4em] font-['Segoe_Print','Bradley_Hand','Comic_Sans_MS',cursive] text-[1.1em] text-[#30343a]">
          {caption}
        </span>
      </motion.button>
    </div>
  );
}