Dynamic Island

// 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;

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

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

"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;
}

"use client";
// beui.dev/components/blocks/dynamic-island

import { AnimatePresence, motion, useReducedMotion } from "motion/react";
import {
  createContext,
  useContext,
  useEffect,
  useLayoutEffect,
  useMemo,
  useRef,
  useState,
  type ReactNode,
} from "react";
import { EASE_OUT } from "@/lib/ease";
import { cn } from "@/lib/utils";

type IslandContextValue = {
  view: string | null;
};

const IslandContext = createContext<IslandContextValue | null>(null);

// Shell physics in Apple's duration/bounce form one long perceptual glide with barely-there bounce, identical in
// both directions. The shell animates real width/height (not transforms), so
// slots are never scale-distorted.
const SHELL_SPRING = {
  type: "spring",
  duration: 0.8,
  bounce: 0.2,
} as const;

// Content gets a touch more life than the shell.
const CONTENT_SPRING = {
  type: "spring",
  duration: 0.8,
  bounce: 0.35,
} as const;

// Constant radius — never animated. The browser clamps it to half the shell
// height, so the pill-to-rounded-rect morph falls out of the resize for free
// with zero chance of corner glitches.
const RADIUS = 32;

// iPhone pill dimensions. Also the shell's pre-measure animate target: if the
// first commit already has a view active (e.g. a click replayed after
// hydration), the shell blooms from the pill instead of rendering expanded
// with no animation. Lives in `animate`, not `initial`, so server and client
// markup agree.
const PILL_WIDTH = 126;
const PILL_HEIGHT = 37;

/** Tracks the natural size of the content so the shell can spring to it. */
function useContentSize() {
  const ref = useRef<HTMLDivElement | null>(null);
  const [size, setSize] = useState<{ width: number; height: number } | null>(
    null,
  );

  // Synchronous mount measure: the shell must own explicit dimensions before
  // the first interaction. ResizeObserver fires async after mount — a quick
  // first press could beat it, leaving the shell auto-sized so the view
  // snapped open instead of springing.
  useLayoutEffect(() => {
    const el = ref.current;
    if (!el) return;
    setSize({ width: el.offsetWidth, height: el.offsetHeight });
  }, []);

  useEffect(() => {
    const el = ref.current;
    if (!el || typeof ResizeObserver === "undefined") return;
    const observer = new ResizeObserver(() => {
      setSize({ width: el.offsetWidth, height: el.offsetHeight });
    });
    observer.observe(el);
    return () => observer.disconnect();
  }, []);

  return [ref, size] as const;
}

function Slot({
  keyId,
  children,
  className,
}: {
  keyId: string;
  children: ReactNode;
  className?: string;
}) {
  const reduce = useReducedMotion();
  return (
    <motion.div
      key={keyId}
      initial={
        reduce
          ? { opacity: 0, filter: "blur(0px)" }
          : { opacity: 0, scale: 0.9, y: -8, filter: "blur(5px)" }
      }
      animate={
        reduce
          ? { opacity: 1, filter: "blur(0px)" }
          : { opacity: 1, scale: 1, y: 0, filter: "blur(0px)" }
      }
      // Exit gets sucked up into the pill — fast, blur-free, before the
      // shrinking shell can clip it.
      exit={
        reduce
          ? { opacity: 0, filter: "blur(0px)", transition: { duration: 0.1 } }
          : {
              opacity: 0,
              scale: 0.9,
              y: -6,
              filter: "blur(0px)",
              transition: { duration: 0.08, ease: EASE_OUT },
            }
      }
      // One spring drives transform, opacity and blur together — no per
      // property tweens, no delays. Content travels with the shell.
      transition={reduce ? { duration: 0.15 } : CONTENT_SPRING}
      // Anchored to the pill line: content unfurls downward out of it and is
      // sucked back up into it.
      style={{ transformOrigin: "top center" }}
      className={cn("flex items-center justify-center", className)}
    >
      {children}
    </motion.div>
  );
}

export interface DynamicIslandProps {
  /** Active view id. `null` shows the compact pill. */
  view: string | null;
  /** Compact pill content, shown when no view is active. */
  compact?: ReactNode;
  /** DynamicIslandView elements. */
  children?: ReactNode;
  className?: string;
}

export function DynamicIsland({
  view,
  compact,
  children,
  className,
}: DynamicIslandProps) {
  const reduce = useReducedMotion();
  const expanded = view !== null;
  const [sizerRef, size] = useContentSize();
  const contextValue = useMemo(() => ({ view }), [view]);

  return (
    <IslandContext.Provider value={contextValue}>
      <motion.div
        role="status"
        aria-live="polite"
        initial={false}
        animate={
          size
            ? { width: size.width, height: size.height }
            : { width: PILL_WIDTH, height: PILL_HEIGHT }
        }
        transition={reduce ? { duration: 0 } : SHELL_SPRING}
        style={{ borderRadius: RADIUS }}
        // items-start pins content to the top edge while the shell springs, so
        // expansion reads as unfurling downward out of the pill. Top-align the
        // island in its parent (like under a notch) to complete the effect.
        className={cn(
          "relative inline-flex items-start justify-center overflow-hidden",
          "bg-foreground text-background shadow-2xl",
          className,
        )}
      >
        {/* w-max keeps this at the natural size of the active content; the
            shell springs toward it. */}
        <div ref={sizerRef} className="w-max">
          <AnimatePresence mode="popLayout" initial={false}>
            {!expanded && compact ? (
              <Slot
                keyId="compact"
                // iPhone pill proportions: ~126 x 37.
                className="min-h-[37px] min-w-[126px] gap-2 px-4 py-1.5 text-xs font-medium"
              >
                {compact}
              </Slot>
            ) : null}
          </AnimatePresence>
          {children}
        </div>
      </motion.div>
    </IslandContext.Provider>
  );
}

export interface DynamicIslandViewProps {
  /** Matches the parent `view` prop when active. */
  id: string;
  children: ReactNode;
  className?: string;
}

export function DynamicIslandView({
  id,
  children,
  className,
}: DynamicIslandViewProps) {
  const ctx = useContext(IslandContext);
  if (!ctx)
    throw new Error("DynamicIslandView must be used inside <DynamicIsland>");
  const active = ctx.view === id;

  return (
    <AnimatePresence mode="popLayout" initial={false}>
      {active ? (
        <Slot keyId={id} className={cn("px-6 py-4", className)}>
          {children}
        </Slot>
      ) : null}
    </AnimatePresence>
  );
}

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 { animate, motion, useInView, useReducedMotion } from "motion/react";
import { useEffect, useMemo, useRef, useState } from "react";
import { EASE_OUT } from "@/lib/ease";
import { cn } from "@/lib/utils";

export interface NumberTickerProps {
  value: number;
  /** Digits to pad to (left). */
  pad?: number;
  /** Per-digit roll duration in seconds. */
  duration?: number;
  /** Stagger between digits. */
  stagger?: number;
  /** Render only after the element enters the viewport. */
  startOnView?: boolean;
  prefix?: string;
  suffix?: string;
  /** Add a small blur during digit rolls. */
  blur?: boolean;
  className?: string;
  digitClassName?: string;
  /** Insert locale group separators (commas). Server-component safe. */
  locale?: boolean;
  /** Custom formatter. Client-only — server components must use `locale` instead. */
  format?: (value: number) => string;
}

const DIGIT_HEIGHT_EM = 1.1;
const DIGITS = Array.from({ length: 10 }, (_, n) => n);

export function NumberTicker({
  value,
  pad,
  duration = 0.9,
  stagger = 0.04,
  startOnView = true,
  prefix,
  suffix,
  blur = false,
  className,
  digitClassName,
  locale,
  format,
}: NumberTickerProps) {
  const containerRef = useRef<HTMLSpanElement>(null);
  const inView = useInView(containerRef, { once: true, amount: 0.6 });
  const [armed, setArmed] = useState(!startOnView);

  useEffect(() => {
    if (startOnView && inView) setArmed(true);
  }, [startOnView, inView]);

  const text = useMemo(() => {
    const rounded = Math.round(value);
    const formatted = format
      ? format(rounded)
      : locale
        ? rounded.toLocaleString()
        : rounded.toString();
    return pad ? formatted.padStart(pad, "0") : formatted;
  }, [value, pad, format, locale]);
  const glyphs = useMemo(() => {
    const chars = text.split("");
    // Key by place value (position from the right): a changing digit keeps its
    // identity and rolls to the new value instead of remounting and replaying
    // from 0. Growing numbers add glyphs on the left without re-keying the
    // ones, tens, hundreds already on screen.
    return chars.map((char, i) => ({ char, id: `g-${chars.length - 1 - i}` }));
  }, [text]);
  const readableText = `${prefix ?? ""}${text}${suffix ?? ""}`;

  // Stagger is an entrance flourish. Once the reveal has played, value
  // changes roll every digit immediately — a per-digit delay on live updates
  // reads as lag.
  const [entered, setEntered] = useState(false);
  useEffect(() => {
    if (!armed || entered) return;
    const total = (duration + glyphs.length * stagger) * 1000;
    const t = window.setTimeout(() => setEntered(true), total);
    return () => window.clearTimeout(t);
  }, [armed, entered, duration, stagger, glyphs.length]);

  return (
    <span
      ref={containerRef}
      className={cn("inline-flex items-center tabular-nums", className)}
    >
      <span className="sr-only">{readableText}</span>
      <span aria-hidden="true" className="inline-flex items-center">
        {prefix ? <span>{prefix}</span> : null}
        {glyphs.map(({ char, id }, i) => {
          const isDigit = /\d/.test(char);
          if (!isDigit) {
            return (
              <span key={id} className="inline-block">
                {char}
              </span>
            );
          }
          const digit = Number(char);
          return (
            <Digit
              key={id}
              digit={armed ? digit : 0}
              delay={entered ? 0 : i * stagger}
              duration={duration}
              blur={blur}
              className={digitClassName}
            />
          );
        })}
        {suffix ? <span>{suffix}</span> : null}
      </span>
    </span>
  );
}

function Digit({
  digit,
  delay,
  duration,
  blur,
  className,
}: {
  digit: number;
  delay: number;
  duration: number;
  blur: boolean;
  className?: string;
}) {
  const reduce = useReducedMotion();
  const columnRef = useRef<HTMLSpanElement>(null);

  useEffect(() => {
    if (reduce || !blur || !columnRef.current || !Number.isFinite(digit)) {
      return;
    }

    const node = columnRef.current;
    const controls = animate(
      node,
      { filter: ["blur(10px)", "blur(0px)"] },
      {
        duration: Math.min(duration * 0.75, 0.32),
        delay,
        ease: EASE_OUT,
      },
    );

    return () => {
      controls.stop();
      node.style.filter = "blur(0px)";
    };
  }, [blur, delay, digit, duration, reduce]);

  return (
    <span
      className={cn("relative inline-block overflow-hidden", className)}
      style={{ height: `${DIGIT_HEIGHT_EM}em`, width: "1ch" }}
    >
      <motion.span
        ref={columnRef}
        initial={{ y: 0 }}
        animate={{ y: `-${digit * DIGIT_HEIGHT_EM}em` }}
        transition={
          reduce
            ? { duration: 0 }
            : { duration, delay, ease: EASE_OUT }
        }
        className="absolute inset-x-0 top-0 flex flex-col items-center will-change-[transform,filter]"
      >
        {DIGITS.map((n) => (
          <span
            key={n}
            className="flex h-[1.1em] items-center justify-center leading-none"
          >
            {n}
          </span>
        ))}
      </motion.span>
    </span>
  );
}

"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-${value}`}
              aria-hidden
              initial="initial"
              animate="animate"
              exit="exit"
              className="absolute left-0 top-0 inline-block whitespace-pre"
            >
              {label.split("").map((char, index) => (
                <motion.span
                  // biome-ignore lint/suspicious/noArrayIndexKey: position is the slot identity.
                  key={index}
                  custom={index * CASCADE_STAGGER}
                  variants={CASCADE_LETTER_VARIANTS}
                  className="inline-block whitespace-pre will-change-[opacity,filter,transform]"
                >
                  {char}
                </motion.span>
              ))}
            </motion.span>
          </AnimatePresence>
        </>
      ) : (
        <AnimatePresence initial={false}>
          <motion.span
            key={`text-${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>
  );
}