Card Dealer

"use client";

import { useEffect, useState } from "react";

/**
 * Returns true only on devices that have a true hover (mouse / trackpad).
 * Touch devices fire phantom `:hover` on tap that sticks until tap-elsewhere
 * — gate hover-only effects (scale lifts, magnetic pulls) behind this.
 */
export function useHoverCapable() {
  const [canHover, setCanHover] = useState(false);

  useEffect(() => {
    if (typeof window === "undefined" || !window.matchMedia) return;
    const mq = window.matchMedia("(hover: hover) and (pointer: fine)");
    const update = () => setCanHover(mq.matches);
    update();
    mq.addEventListener?.("change", update);
    return () => mq.removeEventListener?.("change", update);
  }, []);

  return canHover;
}

import { clsx, type ClassValue } from "clsx"
import { twMerge } from "tailwind-merge"

export function cn(...inputs: ClassValue[]) {
  return twMerge(clsx(inputs))
}

// Shared motion tokens. Easing curves mirror the CSS custom properties in
// globals.css; springs are the canonical physics used across components.
// Strong custom variants — defaults like `ease-in`/`ease-out` feel weak.

export const EASE_OUT = [0.16, 1, 0.3, 1] as const;
export const EASE_IN_OUT = [0.77, 0, 0.175, 1] as const;
export const EASE_DRAWER = [0.32, 0.72, 0, 1] as const;

/** CSS string form of EASE_OUT for inline style transitions. */
export const EASE_OUT_CSS = "cubic-bezier(0.16, 1, 0.3, 1)";

/** Press feedback on buttons and other tappable surfaces. */
export const SPRING_PRESS = {
  type: "spring",
  stiffness: 500,
  damping: 30,
  mass: 0.6,
} as const;

/** Content swaps — label/icon slots trading places inside a control. */
export const SPRING_SWAP = {
  type: "spring",
  stiffness: 460,
  damping: 30,
  mass: 0.55,
} as const;

/** Overlay panel entrances — modals and sheets summoned by pointer. */
export const SPRING_PANEL = {
  type: "spring",
  stiffness: 420,
  damping: 40,
  mass: 0.5,
} as const;

/** Shared-layout glides — pills, indicators and panels morphing between positions. */
export const SPRING_LAYOUT = {
  type: "spring",
  stiffness: 360,
  damping: 32,
  mass: 0.6,
} as const;

/** Cursor-follow physics for decorative mouse tracking (magnetic, tilt, dock). */
export const SPRING_MOUSE = {
  stiffness: 200,
  damping: 15,
  mass: 0.3,
} as const;

/** Dragged handles and fills (sliders) — critically damped `useSpring` config,
 * so the value follows the pointer butterily and never rebounds off an end. */
export const SPRING_GLIDE = {
  stiffness: 700,
  damping: 50,
  mass: 0.5,
} as const;

"use client";
// beui.dev/components/blocks/card-dealer

import {
  type AnimationPlaybackControls,
  arc,
  motion,
  type Transition,
  useAnimate,
  useReducedMotion,
} from "motion/react";
import {
  type ReactNode,
  useLayoutEffect,
  useRef,
  useState,
} from "react";
import { useHoverCapable } from "@/lib/hooks/use-hover-capable";
import { cn } from "@/lib/utils";

export type CardDealerZone = "deck" | "hand" | "pile";

export interface CardDealerCard {
  id: string;
  zone: CardDealerZone;
  /** Accessible name for a card in the hand. */
  label: string;
}

export interface CardDealerProps<T extends CardDealerCard> {
  /** Every card on the table. Order within each zone is the stacking and fan order. */
  cards: T[];
  /** The card's face. */
  renderFace: (card: T) => ReactNode;
  /** The card's back, shown while it sits in the deck. */
  renderBack?: (card: T) => ReactNode;
  /** Makes hand cards buttons. Called with the card's id. */
  onCardSelect?: (id: string) => void;
  /** Card size in px. Default 84 by 120. */
  cardWidth?: number;
  cardHeight?: number;
  /** Most horizontal space between neighbouring hand cards, in px. Default 46. */
  spread?: number;
  /** Rotation between neighbouring hand cards, in degrees. Default 5. */
  angle?: number;
  /** Accessible name for the table. Default "Card table". */
  "aria-label"?: string;
  className?: string;
}

// A card crossing the table arcs high and lands with a small settle; a card
// changing slots inside the hand only hops. Both are tuned here rather than
// borrowed from lib/ease because the arc length is the whole effect.
const FLIGHT: Transition = { type: "spring", visualDuration: 0.55, bounce: 0.18 };
const HOP: Transition = { type: "spring", visualDuration: 0.4, bounce: 0.2 };
// arc() bends relative to the distance travelled. A negative strength puts
// horizontal moves above the line in both directions (automatic direction
// would bend them below).
const FLIGHT_STRENGTH = -0.35;
const HOP_STRENGTH = -0.3;
// Cards in a multi-card move leave one after another, not as a single slab.
// A big move shares a fixed window, so dealing the whole deck still flows.
const STAGGER = 0.045;
const MAX_STAGGER_WINDOW = 0.6;
const EDGE = 16;
const HOVER_LIFT = 18;
const HOVER_PUSH = 14;
// The fan's outermost tilt and drop, whatever the hand size. Small hands sit
// well inside both; a whole deck spread into the hand becomes one shallow
// ribbon instead of cards tipping past vertical.
const MAX_FAN_ANGLE = 40;
const MAX_FAN_DROP = 26;
const FAN_DROP = 2.2;

type Pose = { x: number; y: number; rotate: number; faceDown: boolean; z: number };

/** Stable per-card tilt for the pile, so a card keeps its angle once it lands. */
function pileTilt(id: string) {
  let hash = 0;
  for (const char of id) hash = (hash * 31 + char.charCodeAt(0)) | 0;
  return ((Math.abs(hash) % 17) - 8) * 1.1;
}

/**
 * A card table: a face-down deck, a fanned hand and a discard pile. Every card
 * stays mounted and moving one between zones is just a change of `zone`, so it
 * arcs across the table to its new place, flipping face up or down in flight.
 * Reordering the hand makes cards hop over each other into their new slots.
 */
export function CardDealer<T extends CardDealerCard>({
  cards,
  renderFace,
  renderBack,
  onCardSelect,
  cardWidth = 84,
  cardHeight = 120,
  spread = 46,
  angle = 5,
  "aria-label": ariaLabel = "Card table",
  className,
}: CardDealerProps<T>) {
  const reduce = useReducedMotion();
  const canHover = useHoverCapable();
  const stageRef = useRef<HTMLElement>(null);
  const [size, setSize] = useState<{ width: number; height: number } | null>(null);
  const [hovered, setHovered] = useState<string | null>(null);
  // Where each card was last rendered, read during render to tell a flight
  // from a hop from a card that stayed put. Written after every commit.
  const previous = useRef(new Map<string, { zone: CardDealerZone; slot: number }>());
  const resized = useRef(false);

  useLayoutEffect(() => {
    const stage = stageRef.current;
    if (!stage) return;
    const measure = () => {
      resized.current = true;
      setSize({ width: stage.clientWidth, height: stage.clientHeight });
    };
    measure();
    const observer = new ResizeObserver(measure);
    observer.observe(stage);
    return () => observer.disconnect();
  }, []);

  const deck = cards.filter((card) => card.zone === "deck");
  const hand = cards.filter((card) => card.zone === "hand");
  const pile = cards.filter((card) => card.zone === "pile");

  useLayoutEffect(() => {
    const next = new Map<string, { zone: CardDealerZone; slot: number }>();
    for (const list of [deck, hand, pile])
      list.forEach((card, slot) => {
        next.set(card.id, { zone: card.zone, slot });
      });
    previous.current = next;
    resized.current = false;
  });

  const poseFor = (card: T, slot: number): Pose => {
    const width = size?.width ?? 0;
    const height = size?.height ?? 0;
    if (card.zone === "deck") {
      // A thin visible edge for the first few cards, then the stack stops growing.
      const depth = Math.min(slot, 6) * 0.6;
      return { x: EDGE - depth, y: EDGE - depth, rotate: 0, faceDown: true, z: slot };
    }
    if (card.zone === "pile") {
      return {
        x: width - cardWidth - EDGE,
        y: EDGE,
        rotate: pileTilt(card.id),
        faceDown: false,
        z: 400 + slot,
      };
    }
    const count = hand.length;
    const offset = slot - (count - 1) / 2;
    const edge = Math.max((count - 1) / 2, 1);
    const reach = offset / edge;
    const tilt = Math.min(angle * edge, MAX_FAN_ANGLE);
    const drop = Math.min(FAN_DROP * edge * edge, MAX_FAN_DROP);
    const room = width - cardWidth - EDGE * 2;
    const step = count > 1 ? Math.min(spread, room / (count - 1)) : 0;
    const hoveredSlot = hovered ? hand.findIndex((item) => item.id === hovered) : -1;
    const push =
      hoveredSlot < 0 || slot === hoveredSlot
        ? 0
        : Math.sign(slot - hoveredSlot) * HOVER_PUSH;
    return {
      x: width / 2 - cardWidth / 2 + offset * step + push,
      // Outer cards sit lower so the fan reads as held, not laid flat.
      y:
        height -
        cardHeight -
        EDGE +
        reach * reach * drop -
        (slot === hoveredSlot ? HOVER_LIFT : 0),
      rotate: reach * tilt,
      faceDown: false,
      z: slot === hoveredSlot ? 300 : 100 + slot,
    };
  };

  // Moving cards leave in stacking order, so a deal or a collect fans out.
  let moving = 0;
  const movers = cards.filter((card) => {
    const was = previous.current.get(card.id);
    return was !== undefined && was.zone !== card.zone;
  }).length;
  const stagger = movers > 1 ? Math.min(STAGGER, MAX_STAGGER_WINDOW / (movers - 1)) : 0;
  const transitionFor = (card: T, slot: number): Transition => {
    if (reduce || resized.current) return { duration: 0 };
    const was = previous.current.get(card.id);
    if (!was) return { duration: 0 };
    if (was.zone !== card.zone) {
      const delay = moving * stagger;
      moving += 1;
      return { ...FLIGHT, delay, path: arc({ strength: FLIGHT_STRENGTH }) };
    }
    if (card.zone === "hand" && was.slot !== slot) {
      return { ...HOP, path: arc({ strength: HOP_STRENGTH }) };
    }
    return HOP;
  };

  const renderCard = (card: T, slot: number) => {
    const pose = poseFor(card, slot);
    const interactive = card.zone === "hand" && onCardSelect !== undefined;
    const faces = (
      <motion.span
        aria-hidden="true"
        className="relative block size-full [transform-style:preserve-3d]"
        initial={false}
        animate={{ rotateY: pose.faceDown ? 180 : 0 }}
        transition={reduce ? { duration: 0 } : FLIGHT}
      >
        <span className="absolute inset-0 overflow-hidden rounded-xl [backface-visibility:hidden]">
          {renderFace(card)}
        </span>
        <span className="absolute inset-0 overflow-hidden rounded-xl [backface-visibility:hidden] [transform:rotateY(180deg)]">
          {renderBack ? renderBack(card) : <DefaultBack />}
        </span>
      </motion.span>
    );

    return (
      <CardFrame
        key={card.id}
        pose={pose}
        transition={transitionFor(card, slot)}
        width={cardWidth}
        height={cardHeight}
      >
        {/* The faces never change element, so a card flips in flight instead
            of remounting face up; the button lies over them only in the hand. */}
        <div className="size-full [perspective:800px]">{faces}</div>
        {interactive ? (
          <button
            type="button"
            aria-label={card.label}
            onClick={() => onCardSelect?.(card.id)}
            onPointerEnter={(event) => {
              if (canHover && event.pointerType === "mouse") setHovered(card.id);
            }}
            onPointerLeave={() => setHovered((id) => (id === card.id ? null : id))}
            onFocus={() => setHovered(card.id)}
            onBlur={() => setHovered((id) => (id === card.id ? null : id))}
            className="absolute inset-0 cursor-pointer rounded-xl outline-none focus-visible:ring-2 focus-visible:ring-ring focus-visible:ring-offset-2 focus-visible:ring-offset-background"
          />
        ) : null}
      </CardFrame>
    );
  };

  return (
    <section
      ref={stageRef}
      aria-label={ariaLabel}
      className={cn("relative h-80 w-full touch-manipulation select-none", className)}
    >
      {/* One flat list, so a card changing zones keeps its element and flies
          instead of remounting; zone by zone with the hand in fan order, so
          Tab follows the hand. */}
      {size
        ? [deck, hand, pile].flatMap((zone) =>
            zone.map((card, slot) => renderCard(card, slot)),
          )
        : null}
    </section>
  );
}

/**
 * Moves one card. Imperative so each new move can stop the last one first:
 * a declarative arc path keeps running when its target changes, and a long
 * flight finishing after a quick hop would write its stale end point back.
 */
function CardFrame({
  pose,
  transition,
  width,
  height,
  children,
}: {
  pose: Pose;
  transition: Transition;
  width: number;
  height: number;
  children: ReactNode;
}) {
  const [frame, animateFrame] = useAnimate<HTMLDivElement>();
  const running = useRef<AnimationPlaybackControls | null>(null);

  // biome-ignore lint/correctness/useExhaustiveDependencies: a move starts when the pose changes; the transition belongs to that same render and must not restart a move on its own.
  useLayoutEffect(() => {
    if (!frame.current) return;
    running.current?.stop();
    running.current = animateFrame(
      frame.current,
      { x: pose.x, y: pose.y, rotate: pose.rotate },
      transition,
    );
  }, [pose.x, pose.y, pose.rotate]);

  useLayoutEffect(() => () => running.current?.stop(), []);

  return (
    <div
      ref={frame}
      className="absolute top-0 left-0"
      style={{ width, height, zIndex: pose.z }}
    >
      {children}
    </div>
  );
}

function DefaultBack() {
  return (
    <span className="block size-full rounded-xl border border-border bg-[repeating-linear-gradient(45deg,var(--muted)_0_6px,var(--background)_6px_12px)]" />
  );
}

export type {
  ButtonLinkProps,
  ButtonProps,
  ButtonSize,
  ButtonVariant,
} from "./base";
export { Button, ButtonLink } from "./base";
export type { MagneticButtonProps } from "./magnetic";
export { MagneticButton } from "./magnetic";
export type { MetallicButtonProps } from "./metallic";
export { MetallicButton } from "./metallic";
export type { ButtonState, StatefulButtonProps } from "./stateful";
export { StatefulButton } from "./stateful";

"use client";

import {
  AnimatePresence,
  type HTMLMotionProps,
  motion,
  useReducedMotion,
} from "motion/react";
import {
  forwardRef,
  type PointerEvent,
  type ReactNode,
  useCallback,
  useRef,
  useState,
} from "react";
import { EASE_OUT, SPRING_PRESS } from "@/lib/ease";
import { useHoverCapable } from "@/lib/hooks/use-hover-capable";
import { cn } from "@/lib/utils";

export type ButtonVariant = "primary" | "secondary" | "ghost" | "outline";
export type ButtonSize = "sm" | "md" | "lg" | "icon";

export interface ButtonProps extends Omit<
  HTMLMotionProps<"button">,
  "children"
> {
  variant?: ButtonVariant;
  size?: ButtonSize;
  pressScale?: number;
  /** Spawn a Material-style ripple from the press point. Off by default. */
  ripple?: boolean;
  children?: ReactNode;
}

export interface ButtonLinkProps extends Omit<
  HTMLMotionProps<"a">,
  "children"
> {
  variant?: ButtonVariant;
  size?: ButtonSize;
  pressScale?: number;
  children?: ReactNode;
}

type Ripple = { id: number; x: number; y: number; size: number };

const VARIANT_CLASS: Record<ButtonVariant, string> = {
  primary: "bg-primary text-primary-foreground hover:bg-primary/90",
  secondary: "border border-border bg-card text-foreground hover:border-border",
  ghost: "text-muted-foreground hover:text-foreground hover:bg-muted/60",
  outline:
    "border border-border bg-transparent text-foreground hover:bg-muted/60",
};

const SIZE_CLASS: Record<ButtonSize, string> = {
  sm: "h-8 px-3 text-xs gap-1.5 rounded-full",
  md: "h-10 px-5 text-sm gap-2 rounded-full",
  lg: "h-12 px-6 text-base gap-2 rounded-full",
  icon: "h-8 w-8 rounded-lg",
};

export const Button = forwardRef<HTMLButtonElement, ButtonProps>(
  function Button(
    {
      variant = "primary",
      size = "md",
      pressScale = 0.93,
      ripple = false,
      className,
      children,
      onPointerDown,
      ...rest
    },
    ref,
  ) {
    const reduce = useReducedMotion();
    const canHover = useHoverCapable();
    const [ripples, setRipples] = useState<Ripple[]>([]);
    const nextId = useRef(0);

    const handlePointerDown = useCallback(
      (event: PointerEvent<HTMLButtonElement>) => {
        if (ripple && !reduce) {
          const rect = event.currentTarget.getBoundingClientRect();
          const size = Math.max(rect.width, rect.height) * 2;
          const id = nextId.current++;
          setRipples((prev) => [
            ...prev,
            {
              id,
              x: event.clientX - rect.left,
              y: event.clientY - rect.top,
              size,
            },
          ]);
        }
        onPointerDown?.(event);
      },
      [ripple, reduce, onPointerDown],
    );

    return (
      <motion.button
        ref={ref}
        type="button"
        whileTap={reduce ? undefined : { scale: pressScale }}
        whileHover={reduce || !canHover ? undefined : { scale: 1.02 }}
        transition={SPRING_PRESS}
        onPointerDown={handlePointerDown}
        className={cn(
          "inline-flex items-center justify-center font-medium select-none",
          "transition-colors",
          "disabled:pointer-events-none disabled:opacity-50",
          ripple && "relative overflow-hidden",
          VARIANT_CLASS[variant],
          SIZE_CLASS[size],
          className,
        )}
        {...rest}
      >
        {ripple && !reduce ? (
          <span className="pointer-events-none absolute inset-0 overflow-hidden rounded-[inherit]">
            <AnimatePresence>
              {ripples.map((r) => (
                <motion.span
                  key={r.id}
                  className="absolute rounded-full bg-current"
                  style={{
                    left: r.x,
                    top: r.y,
                    width: r.size,
                    height: r.size,
                    x: "-50%",
                    y: "-50%",
                  }}
                  initial={{ scale: 0.05, opacity: 0.3 }}
                  animate={{ scale: 1, opacity: 0 }}
                  exit={{ opacity: 0 }}
                  transition={{ duration: 1.6, ease: EASE_OUT }}
                  onAnimationComplete={() =>
                    setRipples((prev) => prev.filter((x) => x.id !== r.id))
                  }
                />
              ))}
            </AnimatePresence>
          </span>
        ) : null}
        {children}
      </motion.button>
    );
  },
);

export const ButtonLink = forwardRef<HTMLAnchorElement, ButtonLinkProps>(
  function ButtonLink(
    {
      variant = "primary",
      size = "md",
      pressScale = 0.93,
      className,
      children,
      ...rest
    },
    ref,
  ) {
    const reduce = useReducedMotion();
    const canHover = useHoverCapable();

    return (
      <motion.a
        ref={ref}
        whileTap={reduce ? undefined : { scale: pressScale }}
        whileHover={reduce || !canHover ? undefined : { scale: 1.02 }}
        transition={SPRING_PRESS}
        className={cn(
          "inline-flex items-center justify-center font-medium select-none",
          "transition-colors",
          VARIANT_CLASS[variant],
          SIZE_CLASS[size],
          className,
        )}
        {...rest}
      >
        {children}
      </motion.a>
    );
  },
);

"use client";

import { forwardRef } from "react";
import { Magnetic } from "../magnetic";
import { Button, type ButtonProps } from "./base";

export interface MagneticButtonProps extends ButtonProps {
  /** Magnetic pull strength. Default 0.25. */
  strength?: number;
  /** Class applied to the magnetic wrapper. */
  magneticClassName?: string;
}

export const MagneticButton = forwardRef<HTMLButtonElement, MagneticButtonProps>(function MagneticButton(
  { strength = 0.25, magneticClassName, children, ...rest },
  ref,
) {
  return (
    <Magnetic strength={strength} className={magneticClassName}>
      <Button ref={ref} {...rest}>
        {children}
      </Button>
    </Magnetic>
  );
});

"use client";

import { motion, useReducedMotion } from "motion/react";
import { forwardRef, useState } from "react";
import { EASE_IN_OUT } from "@/lib/ease";
import { cn } from "@/lib/utils";
import { Button, type ButtonProps } from "./base";

export interface MetallicButtonProps extends Omit<
  ButtonProps,
  "ripple" | "variant"
> {
  /** Stops the traveling reflection while preserving the chrome rim. */
  paused?: boolean;
}

// The rim and highlight drift separately so the material stays quiet and reflective.
const SILVER_DRIFT = {
  duration: 8,
  ease: EASE_IN_OUT,
  repeat: Infinity,
};

const CHROME_SHIMMER = {
  duration: 2.4,
  ease: EASE_IN_OUT,
};

export const MetallicButton = forwardRef<
  HTMLButtonElement,
  MetallicButtonProps
>(function MetallicButton(
  {
    size = "md",
    paused = false,
    className,
    children,
    onHoverStart,
    onHoverEnd,
    ...rest
  },
  ref,
) {
  const reduce = useReducedMotion();
  const still = paused || Boolean(reduce);
  const [hovered, setHovered] = useState(false);

  return (
    <Button
      ref={ref}
      variant="ghost"
      size={size}
      onHoverStart={(event, info) => {
        setHovered(true);
        onHoverStart?.(event, info);
      }}
      onHoverEnd={(event, info) => {
        setHovered(false);
        onHoverEnd?.(event, info);
      }}
      className={cn(
        "group relative isolate overflow-hidden border-0 bg-transparent text-foreground",
        "hover:bg-transparent hover:text-foreground",
        "focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-ring focus-visible:ring-offset-2",
        "shadow-[0_8px_22px_rgba(0,0,0,0.16)]",
        size === "icon" && "rounded-full",
        className,
      )}
      {...rest}
    >
      <motion.span
        aria-hidden="true"
        className="pointer-events-none absolute inset-y-0 left-[-18%] z-0 w-[136%] rounded-[inherit] bg-[linear-gradient(105deg,#111_0%,#737373_14%,#fafafa_26%,#525252_38%,#0a0a0a_50%,#a3a3a3_64%,#fff_75%,#404040_87%,#111_100%)]"
        animate={still ? undefined : { x: ["0%", "13%", "0%"] }}
        transition={still ? undefined : SILVER_DRIFT}
      />

      <motion.span
        aria-hidden="true"
        className="pointer-events-none absolute inset-y-0 left-[-58%] z-[1] w-[52%] -skew-x-12 bg-[linear-gradient(90deg,transparent,rgba(255,255,255,0.5)_48%,transparent)] opacity-50 blur-[3px] mix-blend-screen"
        animate={still ? undefined : { x: hovered ? "310%" : "0%" }}
        transition={still ? undefined : CHROME_SHIMMER}
      />

      <span
        aria-hidden="true"
        className="pointer-events-none absolute inset-[2px] z-[2] rounded-[inherit] bg-background transition-colors group-hover:bg-muted/40"
      />

      <span
        aria-hidden="true"
        className="pointer-events-none absolute inset-[2px] z-[3] rounded-[inherit] shadow-[inset_0_1px_0_rgba(255,255,255,0.28),inset_0_-1px_0_rgba(0,0,0,0.16)]"
      />

      <span className="relative z-10 inline-flex items-center justify-center gap-2">
        {children}
      </span>
    </Button>
  );
});

"use client";

import { Check, Loader2, X } from "lucide-react";
import {
  AnimatePresence,
  motion,
  useReducedMotion,
  type Variants,
} from "motion/react";
import {
  forwardRef,
  type ReactNode,
  useLayoutEffect,
  useRef,
  useState,
} from "react";
import { EASE_OUT, SPRING_SWAP } from "@/lib/ease";
import { Button, type ButtonProps } from "./base";

export type ButtonState = "idle" | "loading" | "success" | "error";

export interface StatefulButtonProps extends Omit<ButtonProps, "children"> {
  state?: ButtonState;
  children: ReactNode;
  loadingText?: ReactNode;
  successText?: ReactNode;
  errorText?: ReactNode;
  icon?: ReactNode;
}

const CASCADE_STAGGER = 0.025;
const ROLL_BLUR = "blur(6px)";

const CASCADE_LETTER_VARIANTS: Variants = {
  initial: { opacity: 0, y: "105%", filter: ROLL_BLUR },
  animate: (delay: number = 0) => ({
    opacity: 1,
    y: "0%",
    filter: "blur(0px)",
    transition: { ...SPRING_SWAP, delay },
  }),
  exit: (delay: number = 0) => ({
    opacity: 0,
    y: "-105%",
    filter: ROLL_BLUR,
    transition: { duration: 0.16, ease: EASE_OUT, delay: delay * 0.5 },
  }),
};

const ICON_VARIANTS: Variants = {
  // Width collapses too, so the icon adds/removes its own space smoothly
  // instead of popping the row width in a single frame.
  initial: { opacity: 0, width: 0, scale: 0.7, filter: ROLL_BLUR },
  animate: {
    opacity: 1,
    width: "1.5rem",
    scale: 1,
    filter: "blur(0px)",
    transition: SPRING_SWAP,
  },
  exit: {
    opacity: 0,
    width: 0,
    scale: 0.7,
    filter: ROLL_BLUR,
    transition: { duration: 0.16, ease: EASE_OUT },
  },
};

function IconSlot({ keyId, children }: { keyId: string; children: ReactNode }) {
  const reduce = useReducedMotion();
  return (
    <motion.span
      key={keyId}
      variants={ICON_VARIANTS}
      initial={reduce ? { opacity: 0 } : "initial"}
      animate={reduce ? { opacity: 1 } : "animate"}
      exit={reduce ? { opacity: 0 } : "exit"}
      transition={reduce ? { duration: 0.15 } : undefined}
      className="inline-grid shrink-0 place-items-center overflow-hidden"
    >
      {children}
    </motion.span>
  );
}

function TextSlot({
  value,
  children,
}: {
  value: string;
  children: ReactNode;
}) {
  const reduce = useReducedMotion();
  const measureRef = useRef<HTMLSpanElement>(null);
  const [width, setWidth] = useState<number>();
  const label = typeof children === "string" ? children : null;
  const cascade = label !== null && !reduce;

  // Measure strings with the same per-letter layout as the cascade. Measuring
  // the whole string preserves kerning, which can make it narrower than the
  // inline-block letters and clip the final glyph during the width animation.
  useLayoutEffect(() => {
    const nextWidth = measureRef.current?.offsetWidth;
    if (!nextWidth) return;
    setWidth((current) => (current === nextWidth ? current : nextWidth));
  });

  return (
    <motion.span
      initial={false}
      animate={{ width }}
      transition={reduce ? { duration: 0 } : SPRING_SWAP}
      className="relative inline-block overflow-hidden whitespace-nowrap align-bottom"
    >
      <span
        ref={measureRef}
        aria-hidden
        className="invisible inline-block whitespace-nowrap"
      >
        {cascade
          ? label.split("").map((char, index) => (
              <span
                // biome-ignore lint/suspicious/noArrayIndexKey: position is the slot identity.
                key={index}
                className="inline-block whitespace-pre"
              >
                {char}
              </span>
            ))
          : children}
      </span>

      {cascade ? (
        <>
          <span className="sr-only">{label}</span>
          <AnimatePresence initial={false}>
            <motion.span
              key={`cascade-${value}`}
              aria-hidden
              initial="initial"
              animate="animate"
              exit="exit"
              className="absolute left-0 top-0 inline-block whitespace-pre"
            >
              {label.split("").map((char, index) => (
                <motion.span
                  // biome-ignore lint/suspicious/noArrayIndexKey: position is the slot identity.
                  key={index}
                  custom={index * CASCADE_STAGGER}
                  variants={CASCADE_LETTER_VARIANTS}
                  // Own states: a label that swaps away and straight back
                  // re-enters mid-exit, and only owned targets are restored.
                  initial="initial"
                  animate="animate"
                  exit="exit"
                  className="inline-block whitespace-pre will-change-[opacity,filter,transform]"
                >
                  {char}
                </motion.span>
              ))}
            </motion.span>
          </AnimatePresence>
        </>
      ) : (
        <AnimatePresence initial={false}>
          <motion.span
            key={`text-${value}`}
            initial={reduce ? { opacity: 0 } : { opacity: 0, y: 14, filter: ROLL_BLUR }}
            animate={reduce ? { opacity: 1 } : { opacity: 1, y: 0, filter: "blur(0px)" }}
            exit={reduce ? { opacity: 0 } : { opacity: 0, y: -14, filter: ROLL_BLUR }}
            transition={reduce ? { duration: 0.15 } : SPRING_SWAP}
            className="absolute left-0 top-0 inline-block will-change-[opacity,filter,transform]"
          >
            {children}
          </motion.span>
        </AnimatePresence>
      )}
    </motion.span>
  );
}

export const StatefulButton = forwardRef<HTMLButtonElement, StatefulButtonProps>(function StatefulButton(
  {
    state = "idle",
    children,
    loadingText = "Loading",
    successText = "Done",
    errorText = "Try again",
    icon,
    disabled,
    ...rest
  },
  ref,
) {
  const isBusy = state === "loading";
  const stateText =
    state === "loading"
      ? loadingText
      : state === "success"
        ? successText
        : state === "error"
        ? errorText
        : children;
  const textKey =
    typeof stateText === "string" ? `${state}-${stateText}` : state;

  return (
    <Button ref={ref} disabled={disabled || isBusy} aria-busy={isBusy} whileHover={undefined} {...rest}>
      <span
        aria-live="polite"
        className="relative inline-flex items-center justify-center overflow-hidden"
      >
        <AnimatePresence initial={false}>
          {state === "loading" ? (
            <IconSlot keyId="loading-icon">
              <Loader2 className="h-4 w-4 animate-spin" />
            </IconSlot>
          ) : null}
          {state === "success" ? (
            <IconSlot keyId="success-icon">
              <Check className="h-4 w-4" />
            </IconSlot>
          ) : null}
          {state === "error" ? (
            <IconSlot keyId="error-icon">
              <X className="h-4 w-4" />
            </IconSlot>
          ) : null}
        </AnimatePresence>

        <TextSlot value={textKey}>{stateText}</TextSlot>

        <AnimatePresence initial={false}>
          {state === "idle" && icon ? (
            <IconSlot keyId="idle-icon">{icon}</IconSlot>
          ) : null}
        </AnimatePresence>
      </span>
    </Button>
  );
});

"use client";

import { motion, useMotionValue, useReducedMotion, useSpring } from "motion/react";
import { useRef, type ReactNode } from "react";
import { SPRING_MOUSE } from "@/lib/ease";
import { useHoverCapable } from "@/lib/hooks/use-hover-capable";
import { cn } from "@/lib/utils";

export interface MagneticProps {
  children: ReactNode;
  strength?: number;
  className?: string;
}

export function Magnetic({ children, strength = 0.35, className }: MagneticProps) {
  const ref = useRef<HTMLDivElement>(null);
  const reduce = useReducedMotion();
  const canHover = useHoverCapable();
  // Decorative cursor-follow: skip on touch (phantom hover) and reduced motion.
  const enabled = !reduce && canHover;
  const x = useMotionValue(0);
  const y = useMotionValue(0);
  const sx = useSpring(x, SPRING_MOUSE);
  const sy = useSpring(y, SPRING_MOUSE);

  const onMove = (e: React.MouseEvent<HTMLDivElement>) => {
    const el = ref.current;
    if (!el || !enabled) return;
    const rect = el.getBoundingClientRect();
    x.set((e.clientX - rect.left - rect.width / 2) * strength);
    y.set((e.clientY - rect.top - rect.height / 2) * strength);
  };

  const onLeave = () => {
    x.set(0);
    y.set(0);
  };

  return (
    <motion.div
      ref={ref}
      onMouseMove={onMove}
      onMouseLeave={onLeave}
      style={{ x: sx, y: sy }}
      className={cn("inline-block", className)}
    >
      {children}
    </motion.div>
  );
}