"use client";

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

type StaggerTypeProps = {
  text: string;
  className?: string;
  /** Where the stagger starts: the first letter, the middle, or the last. */
  from?: "start" | "center" | "end";
  /** Seconds between neighbouring letters. */
  stagger?: number;
  /** Play only the first time it scrolls into view. */
  once?: boolean;
};

/* StaggerType: letters drop in from above and settle with a spring, timed outward from the start, centre or end of the line. */
export function StaggerType({ text, className = "", from = "center", stagger = 0.03, once = true }: StaggerTypeProps) {
  const reduce = useReducedMotion();
  if (reduce) return <span className={className}>{text}</span>;

  const words = text.split(" ");
  const starts = words.map((_, w) => words.slice(0, w).join("").length);
  const last = text.replace(/ /g, "").length - 1;
  const origin = from === "start" ? 0 : from === "end" ? last : last / 2;

  return (
    <motion.span className={className} initial="hidden" whileInView="show" viewport={{ once, amount: 0.6 }}>
      <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"
                  custom={Math.abs(starts[w] + i - origin)}
                  variants={{
                    hidden: { opacity: 0, y: "-0.6em", scale: 1.4 },
                    show: (d: number) => ({
                      opacity: 1,
                      y: 0,
                      scale: 1,
                      transition: { type: "spring", stiffness: 300, damping: 20, delay: d * stagger },
                    }),
                  }}
                >
                  {ch}
                </motion.span>
              ))}
            </span>
            {w < words.length - 1 && " "}
          </span>
        ))}
      </span>
    </motion.span>
  );
}