"use client";

import { useRef } from "react";
import { motion, useInView, useReducedMotion } from "motion/react";

type RansomNoteProps = {
  text: string;
  className?: string;
  /** Change it to cut the letters again from other pages. */
  seed?: number;
  /** Seconds between letters landing. */
  stagger?: number;
  /** Play only the first time it scrolls into view. */
  once?: boolean;
};

const CUTS = [
  { paper: "#fbf3df", ink: "#141414", font: "Georgia, serif", weight: 700 },
  { paper: "#141414", ink: "#ffffff", font: "Impact, 'Arial Narrow', sans-serif", weight: 400 },
  { paper: "#e0392b", ink: "#ffffff", font: "'Arial Black', Arial, sans-serif", weight: 900 },
  { paper: "#f6cf45", ink: "#141414", font: "'Times New Roman', serif", weight: 700, italic: true },
  { paper: "#2558b0", ink: "#ffffff", font: "Verdana, sans-serif", weight: 700 },
  { paper: "#ffffff", ink: "#c2185b", font: "'Courier New', monospace", weight: 700 },
  { paper: "#d8d0bc", ink: "#2b2b2b", font: "Arial, Helvetica, sans-serif", weight: 800, dots: true },
  { paper: "#2f8f5b", ink: "#fbf3df", font: "Georgia, serif", weight: 700, italic: true },
];

// Same seed, same note: 0 to 1 from integers, so server and browser agree.
const roll = (n: number) => (Math.imul(n + 7, 2654435761) >>> 16) / 65536;

function scissorCut(n: number) {
  const j = (k: number, most: number) => (roll(n * 8 + k) * most).toFixed(1);
  return `polygon(${j(1, 9)}% ${j(2, 8)}%, 100% ${j(3, 11)}%, ${100 - +j(4, 8)}% ${100 - +j(5, 7)}%, ${j(6, 12)}% 100%)`;
}

/* RansomNote: every letter cut from a different page, then slapped down crooked. Same seed gives the same note. */
export function RansomNote({ text, className = "", seed = 1, stagger = 0.06, once = true }: RansomNoteProps) {
  const reduce = useReducedMotion();
  const box = useRef<HTMLSpanElement>(null);
  const inView = useInView(box, { once, amount: 0.2 });
  let letter = -1;
  let last = -1;

  return (
    <span ref={box} className={`inline-flex flex-wrap items-center justify-center gap-x-[0.42em] gap-y-[0.2em] leading-none ${className}`}>
      <span className="sr-only">{text}</span>
      {text.split(" ").map((word, w) => (
        <span key={`${seed}-${w}`} aria-hidden className="inline-flex items-center whitespace-nowrap">
          {[...word].map((ch, i) => {
            letter += 1;
            const n = seed * 1000 + letter;
            const cut = (last + 1 + Math.floor(roll(n) * (CUTS.length - 1))) % CUTS.length;
            last = cut;
            const look = CUTS[cut];
            const tilt = roll(n + 1) * 14 - 7;
            const lift = roll(n + 2) * 0.16 - 0.08;
            const size = 0.84 + roll(n + 3) * 0.32;
            const glyph = roll(n + 4) > 0.5 ? ch.toUpperCase() : ch.toLowerCase();
            const hidden = { opacity: 0, scale: 1.9, rotate: tilt + 24 };
            return (
              <motion.span
                key={i}
                className="relative -mx-[0.015em] inline-block [filter:drop-shadow(0_0.04em_0.05em_rgba(0,0,0,0.5))]"
                style={{ y: `${lift}em` }}
                initial={reduce ? false : hidden}
                animate={reduce || inView ? { opacity: 1, scale: 1, rotate: tilt } : hidden}
                whileHover={{ scale: 1.18, rotate: 0, zIndex: 2 }}
                transition={{ type: "spring", stiffness: 420, damping: 18, delay: inView ? letter * stagger : 0 }}
              >
                <span
                  className="block px-[0.2em] py-[0.13em]"
                  style={{
                    clipPath: scissorCut(n),
                    backgroundColor: look.paper,
                    backgroundImage: look.dots ? "radial-gradient(rgba(0,0,0,0.2) 1px, transparent 1.3px)" : undefined,
                    backgroundSize: "4px 4px",
                    color: look.ink,
                    fontFamily: look.font,
                    fontWeight: look.weight,
                    fontStyle: look.italic ? "italic" : "normal",
                    fontSize: `${size}em`,
                  }}
                >
                  {glyph}
                </span>
                {letter % 5 === 2 && <span className="absolute -top-[0.08em] left-1/2 h-[0.2em] w-[0.72em] -translate-x-1/2 -rotate-6 bg-[#f1e6b8]/70" />}
              </motion.span>
            );
          })}
        </span>
      ))}
    </span>
  );
}