"use client";

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

type GlyphWaveProps = {
  text: string;
  className?: string;
  /** How high each letter rises, in em. */
  height?: number;
  /** Seconds between one letter and the next. */
  stagger?: number;
  /** Seconds of rest before the wave runs again. */
  rest?: number;
};

/* GlyphWave: a soft wave runs through the letters again and again, each letter rising and settling just after the one before. */
export function GlyphWave({ text, className = "", height = 0.2, stagger = 0.05, rest = 1.2 }: GlyphWaveProps) {
  const reduce = useReducedMotion();
  if (reduce) return <span className={className}>{text}</span>;

  const words = text.split(" ");
  // Each letter's place in the whole text, so the wave carries on across words.
  const starts = words.map((_, w) => words.slice(0, w).join("").length);

  return (
    <span className={className}>
      <span className="sr-only">{text}</span>
      <span aria-hidden>
        {words.map((word, w) => (
          <span key={w}>
            <span className="inline-block whitespace-nowrap">
              {[...word].map((ch, i) => (
                <motion.span
                  key={i}
                  className="inline-block"
                  animate={{ y: ["0em", `-${height}em`, "0em"] }}
                  transition={{ duration: 0.6, ease: "easeInOut", repeat: Infinity, repeatDelay: rest, delay: (starts[w] + i) * stagger }}
                >
                  {ch}
                </motion.span>
              ))}
            </span>
            {w < words.length - 1 && " "}
          </span>
        ))}
      </span>
    </span>
  );
}