호버 카드

/* A floating layer, so it earns the floating shadow. Transforms pivot on the placed origin, the corner nearest the trigger. */
.card { z-index: 60; box-sizing: border-box; width: 18.5rem; max-width: min(18.5rem, var(--radix-popover-content-available-width, calc(100vw - 24px))); padding: var(--space-4); border: 1px solid var(--float-edge, var(--surface-raised)); border-radius: var(--radius-panel); background: var(--surface-raised); color: var(--foreground); box-shadow: var(--shadow-floating); font-family: var(--font-body); letter-spacing: var(--tracking-body); transform-origin: var(--radix-popover-content-transform-origin); outline: none; }
.profile { display: grid; gap: var(--space-3); }
.head { display: flex; min-width: 0; align-items: center; gap: var(--space-3); }
.avatar { position: relative; display: grid; width: 48px; height: 48px; flex: none; place-items: center; overflow: hidden; border: 1px solid var(--border); border-radius: var(--radius-pill); background: var(--surface-muted); color: var(--foreground); font-size: var(--text-sm); font-weight: 500; }
.avatar img { display: block; width: 100%; height: 100%; object-fit: cover; transition: opacity var(--duration-standard) var(--ease-enter), filter var(--duration-standard) var(--ease-enter); }
.avatar img[data-loading] { opacity: 0; filter: blur(4px); transition: none; }
.identity { display: grid; min-width: 0; }
.name, .role { overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.name { color: var(--foreground); font-size: var(--text-base); font-weight: 500; line-height: var(--leading-body); }
.role { color: var(--text-secondary); font-size: var(--text-sm); line-height: var(--leading-body); }
.bio { margin: 0; color: var(--text-secondary); font-size: var(--text-sm); line-height: var(--leading-body); }
/* Numbers lead and labels follow, while the markup keeps label then value for screen readers. */
.stats { display: flex; flex-wrap: wrap; gap: var(--space-2) var(--space-6); margin: 0; padding-top: var(--space-3); border-top: 1px solid var(--border-subtle); }
.stat { display: flex; flex-direction: column-reverse; }
.stat dt { color: var(--text-muted); font-size: var(--text-xs); line-height: var(--leading-body); }
.stat dd { margin: 0; color: var(--foreground); font-size: var(--text-base); font-variant-numeric: tabular-nums; font-weight: 500; line-height: var(--leading-body); }
.meta { display: flex; align-items: center; gap: 6px; color: var(--text-muted); font-size: var(--text-xs); line-height: var(--leading-body); }
.meta svg { flex: none; }
@media (prefers-reduced-motion: reduce) { .avatar img { transition: none; } .avatar img[data-loading] { filter: none; } }

"use client";

import { forwardRef, useCallback, useEffect, useId, useLayoutEffect, useRef, useState, useSyncExternalStore } from "react";
import type { FocusEvent, HTMLAttributes, PointerEvent, ReactElement, ReactNode } from "react";
import * as PopoverPrimitive from "@radix-ui/react-popover";
import { AnimatePresence, animate, motion, useMotionValue, usePresence } from "motion/react";
import { useReducedMotion } from "../lib/use-reduced-motion";
import { motionTokens } from "../lib/motion-tokens";
import styles from "./hover-card.module.css";

const OPEN_DELAY = 500;
const CLOSE_DELAY = 140;
/** Moving to another trigger within this window opens its card almost at once. */
const SKIP_WINDOW = 300;
/** Even warm, a trigger waits this long, so a pointer crossing it on the way into an open card does not steal the card. */
const INTENT = 80;
/** How far the card starts toward its trigger, in px. */
const TRAVEL = 4;
const enter = [...motionTokens.ease.enter] as [number, number, number, number];
const standard = [...motionTokens.ease.standard] as [number, number, number, number];

type Snapshot = { id: string | null; instant: boolean };
const IDLE: Snapshot = { id: null, instant: false };
let snapshot = IDLE;
let closedAt = -Infinity;
const listeners = new Set<() => void>();
/** One hover card is open at a time on the page. While one is open, or just after it closes, the next one opens without waiting and only fades. */
const cards = {
  subscribe(listener: () => void) { listeners.add(listener); return () => { listeners.delete(listener); }; },
  get: () => snapshot,
  server: () => IDLE,
  warm: () => snapshot.id !== null || performance.now() - closedAt < SKIP_WINDOW,
  open(id: string) { if (snapshot.id === id) return; snapshot = { id, instant: cards.warm() }; listeners.forEach(listener => listener()); },
  close(id: string) { if (snapshot.id !== id) return; snapshot = IDLE; closedAt = performance.now(); listeners.forEach(listener => listener()); },
};

/**
 * A rich preview of a person or link that opens after a short hover or keyboard focus, for mentions, avatars, and references where a click should stay free for navigation.
 * It waits half a second, opens almost at once when moving between triggers, stays open while the pointer travels into it, and closes fast on leave or Escape.
 * On touch, a tap toggles it. Keep the content read only; anything actionable belongs behind the trigger itself.
 */
export interface HoverCardProps {
  /** The trigger, such as a mention button or a link. It must accept a ref and be focusable. */
  children: ReactElement;
  /** The preview. `HoverCardProfile` covers people; any read only content works. */
  content: ReactNode;
  side?: "top" | "bottom" | "left" | "right";
  align?: "start" | "center" | "end";
  /** Milliseconds of hover before the first card opens. */
  openDelay?: number;
  /** Milliseconds of grace after the pointer leaves, so it can travel into the card. */
  closeDelay?: number;
  className?: string;
}

interface SurfaceProps extends Omit<HTMLAttributes<HTMLDivElement>, "onDrag" | "onDragStart" | "onDragEnd" | "onAnimationStart"> { instant: boolean; reduced: boolean }

/** Grows from the trigger edge: scale from .96 around the placed origin and a 4px offset toward the trigger on one smooth spring, with its own fade.
 *  Both retarget from where they are if the pointer comes back mid-exit, so the card turns around instead of jumping. */
const Surface = forwardRef<HTMLDivElement, SurfaceProps>(function Surface({ instant, reduced, className, style, children, ...props }, forwardedRef) {
  const [isPresent, safeToRemove] = usePresence();
  const node = useRef<HTMLDivElement | null>(null);
  const progress = useMotionValue(0);
  const x = useMotionValue(0), y = useMotionValue(0), scale = useMotionValue(1), opacity = useMotionValue(0);
  // Decided when the card mounts: a card revived mid-exit keeps the path it came in on, even though the page is now warm.
  const [still] = useState(() => instant || reduced);
  const setRef = useCallback((element: HTMLDivElement | null) => {
    node.current = element;
    if (typeof forwardedRef === "function") forwardedRef(element); else if (forwardedRef) forwardedRef.current = element;
  }, [forwardedRef]);

  useEffect(() => {
    let cancelled = false;
    // The side is read from the placed card every frame, so a card that flips above its trigger still grows from the trigger edge.
    const apply = (value: number) => {
      const side = node.current?.dataset.side;
      const travel = still ? 0 : (1 - value) * TRAVEL;
      x.set(side === "left" ? travel : side === "right" ? -travel : 0);
      y.set(side === "top" ? travel : side === "bottom" ? -travel : 0);
      scale.set(still ? 1 : .96 + .04 * value);
    };
    const unsubscribe = progress.on("change", apply);
    apply(progress.get());
    const controls = isPresent
      ? animate(progress, 1, still ? { duration: motionTokens.duration.instant, ease: enter } : motionTokens.spring.smooth)
      : animate(progress, 0, { duration: motionTokens.duration.instant, ease: standard });
    // The fade leads the grow on the way in and runs alongside it on the way out; it starts from the current opacity either way.
    const fade = isPresent
      ? animate(opacity, 1, { duration: reduced ? motionTokens.duration.fast : still ? motionTokens.duration.micro : motionTokens.duration.fast, ease: enter })
      : animate(opacity, 0, { duration: reduced ? motionTokens.duration.instant : motionTokens.duration.instant, ease: standard });
    if (!isPresent) fade.then(() => { if (!cancelled) safeToRemove?.(); });
    return () => { cancelled = true; unsubscribe(); controls.stop(); fade.stop(); };
  }, [isPresent, still, reduced, progress, x, y, scale, opacity, safeToRemove]);

  return <motion.div {...props} ref={setRef} className={[styles.card, className].filter(Boolean).join(" ")} style={{ ...style, x, y, scale, opacity }}>
    {children}
  </motion.div>;
});

export function HoverCard({ children, content, side = "bottom", align = "start", openDelay = OPEN_DELAY, closeDelay = CLOSE_DELAY, className }: HoverCardProps) {
  const id = useId();
  const cardId = `${id}-card`;
  const state = useSyncExternalStore(cards.subscribe, cards.get, cards.server);
  const open = state.id === id;
  const reduced = useReducedMotion() ?? false;
  const triggerRef = useRef<HTMLDivElement>(null);
  const timers = useRef({ open: 0, close: 0 });
  const inside = useRef({ trigger: false, card: false, focus: false });
  /** Set by Escape, so a pointer resting on the trigger does not reopen what was just dismissed. */
  const dismissed = useRef(false);
  const pointerType = useRef("");

  useEffect(() => {
    const pending = timers.current;
    return () => { window.clearTimeout(pending.open); window.clearTimeout(pending.close); cards.close(id); };
  }, [id]);

  const clearTimers = () => { window.clearTimeout(timers.current.open); window.clearTimeout(timers.current.close); };
  const show = () => { clearTimers(); dismissed.current = false; cards.open(id); };
  const hide = () => { clearTimers(); cards.close(id); };
  const scheduleOpen = () => {
    window.clearTimeout(timers.current.close);
    if (dismissed.current || cards.get().id === id) return;
    window.clearTimeout(timers.current.open);
    timers.current.open = window.setTimeout(() => cards.open(id), cards.warm() ? INTENT : openDelay);
  };
  const scheduleClose = () => {
    window.clearTimeout(timers.current.open);
    const { trigger, card, focus } = inside.current;
    if (trigger || card || focus) return;
    window.clearTimeout(timers.current.close);
    timers.current.close = window.setTimeout(() => cards.close(id), closeDelay);
  };
  const mouse = (event: PointerEvent) => event.pointerType !== "touch";

  return <PopoverPrimitive.Root open={open} onOpenChange={next => { if (!next) hide(); }}>
    <PopoverPrimitive.Anchor asChild ref={triggerRef} aria-describedby={open ? cardId : undefined} data-hover-card={open ? "open" : "closed"}
      onPointerEnter={(event: PointerEvent) => { if (!mouse(event)) return; inside.current.trigger = true; scheduleOpen(); }}
      onPointerLeave={(event: PointerEvent) => { if (!mouse(event)) return; inside.current.trigger = false; dismissed.current = false; scheduleClose(); }}
      onPointerDown={(event: PointerEvent) => { pointerType.current = event.pointerType; }}
      onClick={() => {
        // A tap toggles the card on touch; a click or Enter opens it without the wait.
        const isOpen = cards.get().id === id;
        if (pointerType.current === "touch") { if (isOpen) hide(); else show(); } else if (!isOpen) show();
        pointerType.current = "";
      }}
      onFocus={(event: FocusEvent<HTMLElement>) => { if (!event.currentTarget.matches(":focus-visible")) return; inside.current.focus = true; show(); }}
      onBlur={() => { inside.current.focus = false; dismissed.current = false; scheduleClose(); }}>
      {children}
    </PopoverPrimitive.Anchor>
    <AnimatePresence>
      {open && <PopoverPrimitive.Portal forceMount key="card">
        <PopoverPrimitive.Content forceMount asChild id={cardId} role="tooltip" side={side} align={align} sideOffset={8} collisionPadding={12}
          onOpenAutoFocus={event => event.preventDefault()} onCloseAutoFocus={event => event.preventDefault()}
          onEscapeKeyDown={() => { dismissed.current = true; }}
          onInteractOutside={event => { if (triggerRef.current?.contains(event.target as Node)) event.preventDefault(); }}
          onPointerEnter={(event: PointerEvent) => { if (!mouse(event)) return; inside.current.card = true; window.clearTimeout(timers.current.close); }}
          onPointerLeave={(event: PointerEvent) => { if (!mouse(event)) return; inside.current.card = false; scheduleClose(); }}>
          <Surface instant={state.instant} reduced={reduced} className={className}>{content}</Surface>
        </PopoverPrimitive.Content>
      </PopoverPrimitive.Portal>}
    </AnimatePresence>
  </PopoverPrimitive.Root>;
}

export interface HoverCardStat { label: string; value: string | number }

/** A person preview for `HoverCard`: portrait, name, role, a short bio, a couple of numbers, and a quiet footer line. Its rows settle in with a tiny stagger. */
export interface HoverCardProfileProps {
  name: string;
  /** Role and team, such as "제품 디자이너, 결제팀". */
  role?: string;
  /** A portrait URL, or your own image element such as next/image. Initials show when it is missing. */
  avatar?: string | ReactNode;
  bio?: string;
  stats?: HoverCardStat[];
  /** A footer line, such as a location and local time. */
  meta?: ReactNode;
}

function Portrait({ src }: { src: string }) {
  const image = useRef<HTMLImageElement>(null);
  // A cached portrait shows at once; one still downloading fades in from a soft blur.
  useLayoutEffect(() => { const node = image.current; if (node && !node.complete) node.dataset.loading = ""; }, [src]);
  // eslint-disable-next-line @next/next/no-img-element -- registry components stay framework agnostic; pass next/image through `avatar` instead.
  return <img ref={image} src={src} alt="" width={48} height={48} decoding="async" onLoad={event => { delete event.currentTarget.dataset.loading; }} />;
}

export function HoverCardProfile({ name, role, avatar, bio, stats = [], meta }: HoverCardProfileProps) {
  const reduced = useReducedMotion() ?? false;
  const initials = name.trim().split(/\s+/).slice(0, 2).map(part => part[0]?.toUpperCase()).join("");
  const settle = (order: number) => reduced ? {} : { initial: { opacity: 0, y: 4 }, animate: { opacity: 1, y: 0 }, transition: { duration: motionTokens.duration.standard, ease: enter, delay: .04 + order * motionTokens.stagger.item } };
  return <div className={styles.profile}>
    <motion.div className={styles.head} {...settle(0)}>
      <span className={styles.avatar} aria-hidden="true">{typeof avatar === "string" ? <Portrait src={avatar} /> : avatar ?? <span className={styles.initials}>{initials}</span>}</span>
      <span className={styles.identity}><span className={styles.name}>{name}</span>{role && <span className={styles.role}>{role}</span>}</span>
    </motion.div>
    {bio && <motion.p className={styles.bio} {...settle(1)}>{bio}</motion.p>}
    {stats.length > 0 && <motion.dl className={styles.stats} {...settle(2)}>
      {stats.map(stat => <div key={stat.label} className={styles.stat}><dt>{stat.label}</dt><dd>{stat.value}</dd></div>)}
    </motion.dl>}
    {meta && <motion.div className={styles.meta} {...settle(3)}>{meta}</motion.div>}
  </div>;
}

export default HoverCard;