"use client";

import { useEffect, useRef, useState } from "react";
import { createPortal } from "react-dom";

type TipState = {
  text: string;
  x: number;
  y: number;
  place: "top" | "bottom";
} | null;

/**
 * 全站悬停即显提示：监听 [data-tip]，替代浏览器原生 title 的延迟气泡。
 * 挂在 root layout 即可，业务侧写 data-tip="文案" 并保留 aria-label。
 */
export default function TipHost() {
  const [tip, setTip] = useState<TipState>(null);
  const tipRef = useRef<HTMLDivElement>(null);
  const activeEl = useRef<Element | null>(null);

  useEffect(() => {
    const hide = () => {
      activeEl.current = null;
      setTip(null);
    };

    const placeTip = (el: Element, text: string) => {
      const rect = el.getBoundingClientRect();
      const preferBottom = rect.top < 48;
      const x = rect.left + rect.width / 2;
      const y = preferBottom ? rect.bottom + 8 : rect.top - 8;
      setTip({
        text,
        x,
        y,
        place: preferBottom ? "bottom" : "top",
      });
    };

    const onOver = (e: Event) => {
      const t = e.target;
      if (!(t instanceof Element)) return;
      const host = t.closest("[data-tip]");
      if (!host) {
        if (activeEl.current) hide();
        return;
      }
      const text = host.getAttribute("data-tip")?.trim();
      if (!text) {
        hide();
        return;
      }
      activeEl.current = host;
      placeTip(host, text);
    };

    const onOut = (e: Event) => {
      if (!(e instanceof MouseEvent)) return;
      const related = e.relatedTarget;
      if (
        related instanceof Node &&
        activeEl.current &&
        activeEl.current.contains(related)
      ) {
        return;
      }
      hide();
    };

    const onScrollOrResize = () => {
      if (!activeEl.current) return;
      const text = activeEl.current.getAttribute("data-tip")?.trim();
      if (!text) {
        hide();
        return;
      }
      placeTip(activeEl.current, text);
    };

    // mouseover 冒泡，便于 closest；立即显示，无延时
    document.addEventListener("mouseover", onOver);
    document.addEventListener("mouseout", onOut);
    document.addEventListener("focusin", onOver);
    document.addEventListener("focusout", onOut);
    window.addEventListener("scroll", onScrollOrResize, true);
    window.addEventListener("resize", onScrollOrResize);

    return () => {
      document.removeEventListener("mouseover", onOver);
      document.removeEventListener("mouseout", onOut);
      document.removeEventListener("focusin", onOver);
      document.removeEventListener("focusout", onOut);
      window.removeEventListener("scroll", onScrollOrResize, true);
      window.removeEventListener("resize", onScrollOrResize);
    };
  }, []);

  // 测量后微调，避免贴边裁切
  useEffect(() => {
    if (!tip || !tipRef.current) return;
    const el = tipRef.current;
    const w = el.offsetWidth;
    const pad = 10;
    let left = tip.x;
    const half = w / 2;
    if (left - half < pad) left = pad + half;
    if (left + half > window.innerWidth - pad) {
      left = window.innerWidth - pad - half;
    }
    el.style.left = `${left}px`;
  }, [tip]);

  if (!tip) return null;

  return createPortal(
    <div
      ref={tipRef}
      role="tooltip"
      className="j13-tip-bubble"
      data-place={tip.place}
      style={{
        left: tip.x,
        top: tip.y,
        transform:
          tip.place === "top"
            ? "translate(-50%, -100%)"
            : "translate(-50%, 0)",
      }}
    >
      {tip.text}
    </div>,
    document.body
  );
}