import { useEffect, useRef, useState, type ElementType, type ReactNode } from "react";
import { cn } from "@/lib/utils";

export function Reveal({
  children,
  className,
  as: Tag = "div",
  delay = 0,
}: {
  children: ReactNode;
  className?: string;
  as?: ElementType;
  delay?: number;
}) {
  const ref = useRef<HTMLElement | null>(null);
  const [visible, setVisible] = useState(false);

  useEffect(() => {
    const el = ref.current;
    if (!el) return;
    if (typeof IntersectionObserver === "undefined") {
      setVisible(true);
      return;
    }
    const io = new IntersectionObserver(
      (entries) => {
        entries.forEach((entry) => {
          if (entry.isIntersecting) {
            setVisible(true);
            io.disconnect();
          }
        });
      },
      { rootMargin: "0px 0px -10% 0px", threshold: 0.05 },
    );
    io.observe(el);
    return () => io.disconnect();
  }, []);

  return (
    <Tag
      ref={ref}
      className={cn("reveal", className)}
      data-visible={visible ? "true" : "false"}
      style={delay ? { transitionDelay: `${delay}ms` } : undefined}
    >
      {children}
    </Tag>
  );
}