"use client";

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

type PixelLoaderProps = {
  className?: string;
  color?: string;
  /** Loader width in pixels. */
  size?: number;
  /** 1 is the default pace; 2 is twice as fast. */
  speed?: number;
  /** Read out by screen readers. */
  label?: string;
};

// Clockwise path round the outer cells of a 3x3 grid; cell 4 is the centre.
const RING = [0, 1, 2, 5, 8, 7, 6, 3];

/* PixelLoader: a lit pixel runs round a 3x3 grid, leaving a fading trail. */
export function PixelLoader({
  className = "",
  color = "#a78bfa",
  size = 56,
  speed = 1,
  label = "Loading",
}: PixelLoaderProps) {
  const reduce = useReducedMotion();
  const cycle = 1.2 / speed;
  const gap = size * 0.08;
  const cell = (size - gap * 2) / 3;

  return (
    <div
      role="status"
      className={`inline-grid grid-cols-3 ${className}`}
      style={{ width: size, height: size, gap }}
    >
      <span className="sr-only">{label}</span>
      {Array.from({ length: 9 }, (_, i) => {
        const step = RING.indexOf(i);
        const isCentre = step === -1;
        return (
          <motion.span
            key={i}
            aria-hidden
            className="block rounded-[2px]"
            style={{ width: cell, height: cell, background: color, boxShadow: `0 0 ${cell / 2}px ${color}` }}
            initial={{ opacity: 0.15 }}
            animate={
              reduce
                ? { opacity: [0.3, 0.8, 0.3] }
                : isCentre
                  ? { opacity: [0.25, 0.5, 0.25], scale: [0.85, 1, 0.85] }
                  : { opacity: [0.15, 1, 0.15, 0.15] }
            }
            transition={
              reduce
                ? { duration: 3, repeat: Infinity, ease: "easeInOut" }
                : isCentre
                  ? { duration: cycle, repeat: Infinity, ease: "easeInOut" }
                  : { duration: cycle, times: [0, 0.08, 0.55, 1], repeat: Infinity, ease: "linear", delay: (step * cycle) / RING.length }
            }
          />
        );
      })}
    </div>
  );
}