Todo List

// 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";
// beui.dev/components/agents/todo-list

import { ChevronDown, ListTodo } from "lucide-react";
import { AnimatePresence, motion, useReducedMotion } from "motion/react";
import {
  type ReactNode,
  useCallback,
  useEffect,
  useId,
  useLayoutEffect,
  useRef,
  useState,
} from "react";
import { ActionSwapRollText } from "@/components/motion/action-swap-roll";
import { AgentDisclosure } from "@/components/agents/agent-disclosure";
import {
  EASE_OUT,
  SPRING_LAYOUT,
  SPRING_SWAP,
} from "@/lib/ease";
import { cn } from "@/lib/utils";

export type TodoItemStatus =
  | "pending"
  | "in-progress"
  | "completed"
  | "cancelled";

export interface TodoItem {
  id: string;
  title: ReactNode;
  status?: TodoItemStatus;
  progress?: number;
  detail?: ReactNode;
}

export interface TodoListProps {
  items: TodoItem[];
  title?: ReactNode;
  open?: boolean;
  defaultOpen?: boolean;
  onOpenChange?: (open: boolean) => void;
  collapseOnComplete?: boolean;
  maxHeight?: number;
  className?: string;
}

function statusLabel(status: TodoItemStatus) {
  if (status === "in-progress") return "In progress";
  if (status === "completed") return "Completed";
  if (status === "cancelled") return "Cancelled";
  return "Pending";
}

function TodoHeaderIcon({ complete }: { complete: boolean }) {
  const reduce = useReducedMotion() ?? false;

  return (
    <span
      aria-hidden="true"
      className="relative grid size-6 shrink-0 place-items-center"
    >
      <AnimatePresence initial={false} mode="popLayout">
        {complete ? (
          <motion.svg
            key="complete"
            viewBox="0 0 24 24"
            initial={reduce ? { opacity: 1 } : { opacity: 0, scale: 0.72 }}
            animate={{ opacity: 1, scale: 1 }}
            exit={{ opacity: 0 }}
            transition={reduce ? { duration: 0 } : SPRING_SWAP}
            className="absolute size-5.5 overflow-visible text-emerald-500"
          >
            <circle cx="12" cy="12" r="9" fill="currentColor" />
            <motion.path
              d="M7.5 12.25 10.5 15.25 16.75 8.75"
              fill="none"
              stroke="white"
              strokeWidth="2.25"
              strokeLinecap="round"
              strokeLinejoin="round"
              initial={reduce ? { pathLength: 1 } : { pathLength: 0 }}
              animate={{ pathLength: 1 }}
              transition={
                reduce ? { duration: 0 } : { duration: 0.24, ease: EASE_OUT }
              }
            />
          </motion.svg>
        ) : (
          <motion.span
            key="todo"
            initial={reduce ? { opacity: 1 } : { opacity: 0, scale: 0.8 }}
            animate={{ opacity: 1, scale: 1 }}
            exit={reduce ? { opacity: 0 } : { opacity: 0, scale: 0.72 }}
            transition={reduce ? { duration: 0 } : SPRING_SWAP}
            className="absolute grid place-items-center text-muted-foreground"
          >
            <ListTodo className="size-4" />
          </motion.span>
        )}
      </AnimatePresence>
    </span>
  );
}

function TodoStatusIcon({
  status,
  progress,
}: {
  status: TodoItemStatus;
  progress?: number;
}) {
  const reduce = useReducedMotion() ?? false;
  const normalizedProgress =
    progress === undefined ? 0.68 : Math.min(100, Math.max(0, progress)) / 100;

  return (
    <motion.svg
      aria-hidden="true"
      viewBox="0 0 24 24"
      initial={false}
      className={cn(
        "mx-0.5 size-5 shrink-0 overflow-visible text-muted-foreground",
        status === "in-progress" && "text-foreground",
        status === "cancelled" && "text-rose-600 dark:text-rose-400",
      )}
    >
      <motion.circle
        cx="12"
        cy="12"
        r="9"
        fill="currentColor"
        stroke="currentColor"
        strokeWidth="1.5"
        strokeDasharray={status === "pending" ? "2 3" : undefined}
        strokeLinecap="round"
        initial={false}
        animate={{ fillOpacity: status === "completed" ? 0.06 : 0 }}
        transition={reduce ? { duration: 0 } : { duration: 0.18, ease: EASE_OUT }}
        className={cn(status === "in-progress" && "opacity-20")}
      />
      <motion.circle
        cx="12"
        cy="12"
        r="9"
        pathLength="1"
        fill="none"
        stroke="currentColor"
        strokeWidth="2"
        strokeLinecap="round"
        initial={false}
        animate={{
          pathLength: status === "in-progress" ? normalizedProgress : 0,
          opacity: status === "in-progress" ? 1 : 0,
          rotate:
            status === "in-progress" && progress === undefined && !reduce
              ? 360
              : -90,
        }}
        transition={
          status === "in-progress" && progress === undefined && !reduce
            ? { rotate: { duration: 1.1, repeat: Infinity, ease: "linear" } }
            : reduce
              ? { duration: 0 }
              : SPRING_LAYOUT
        }
        style={{ transformOrigin: "12px 12px" }}
      />
      <motion.path
        d="M7.5 12.25 10.5 15.25 16.75 8.75"
        fill="none"
        stroke="currentColor"
        strokeWidth="2"
        strokeLinecap="round"
        strokeLinejoin="round"
        initial={false}
        animate={{
          pathLength: status === "completed" ? 1 : 0,
          opacity: status === "completed" ? 1 : 0,
        }}
        transition={reduce ? { duration: 0 } : { duration: 0.24, ease: EASE_OUT }}
      />
      <motion.path
        d="M8.5 8.5 15.5 15.5M15.5 8.5 8.5 15.5"
        fill="none"
        stroke="currentColor"
        strokeWidth="2"
        strokeLinecap="round"
        initial={false}
        animate={{
          pathLength: status === "cancelled" ? 1 : 0,
          opacity: status === "cancelled" ? 1 : 0,
        }}
        transition={reduce ? { duration: 0 } : { duration: 0.2, ease: EASE_OUT }}
      />
    </motion.svg>
  );
}

export function TodoList({
  items,
  title = "To-dos",
  open,
  defaultOpen = true,
  onOpenChange,
  collapseOnComplete = true,
  maxHeight = 248,
  className,
}: TodoListProps) {
  const reduce = useReducedMotion() ?? false;
  const baseId = useId();
  const triggerId = `${baseId}-trigger`;
  const contentId = `${baseId}-content`;
  const viewportRef = useRef<HTMLDivElement>(null);
  const previousComplete = useRef(false);
  const [internalOpen, setInternalOpen] = useState(defaultOpen);
  const currentOpen = open ?? internalOpen;
  const completed = items.filter((item) => item.status === "completed").length;
  const allComplete = items.length > 0 && completed === items.length;
  const itemCount = items.length;

  const setOpen = useCallback(
    (next: boolean) => {
      if (open === undefined) setInternalOpen(next);
      onOpenChange?.(next);
    },
    [onOpenChange, open],
  );

  useEffect(() => {
    if (previousComplete.current && !allComplete) {
      setOpen(true);
    }
    if (!previousComplete.current && allComplete && collapseOnComplete) {
      setOpen(false);
    }
    previousComplete.current = allComplete;
  }, [allComplete, collapseOnComplete, setOpen]);

  useLayoutEffect(() => {
    const viewport = viewportRef.current;
    if (!viewport || itemCount === 0) return;

    const frame = requestAnimationFrame(() => {
      if (viewport.scrollHeight <= viewport.clientHeight) return;
      if (typeof viewport.scrollTo === "function") {
        viewport.scrollTo({
          top: viewport.scrollHeight,
          behavior: reduce ? "auto" : "smooth",
        });
      } else {
        viewport.scrollTop = viewport.scrollHeight;
      }
    });
    return () => cancelAnimationFrame(frame);
  }, [itemCount, reduce]);

  return (
    <section
      aria-label="Agent task list"
      className={cn(
        "w-full overflow-hidden rounded-2xl border border-border/70",
        className,
      )}
    >
      <button
        id={triggerId}
        type="button"
        aria-expanded={currentOpen}
        aria-controls={contentId}
        onClick={() => setOpen(!currentOpen)}
        className="group flex h-11 w-full items-center gap-2.5 rounded-2xl px-3.5 text-left outline-none focus-visible:ring-2 focus-visible:ring-ring"
      >
        <TodoHeaderIcon complete={allComplete} />
        <h3 className="min-w-0 flex-1 truncate text-sm font-medium text-foreground/90">
          {title}
        </h3>
        <span
          className={cn(
            "shrink-0 text-xs font-medium tabular-nums text-muted-foreground",
            allComplete && "text-emerald-600 dark:text-emerald-400",
          )}
        >
          <span className="sr-only">
            {completed} of {items.length} tasks completed
          </span>
          <span aria-hidden="true" className="inline-flex">
            <ActionSwapRollText value={String(completed)}>
              {completed}
            </ActionSwapRollText>
            <span>/</span>
            <span>{items.length}</span>
          </span>
        </span>
        <motion.span
          aria-hidden="true"
          animate={{ rotate: currentOpen ? 180 : 0 }}
          transition={reduce ? { duration: 0 } : SPRING_SWAP}
          className="text-muted-foreground/50 transition-colors group-hover:text-muted-foreground"
        >
          <ChevronDown className="size-3.5" />
        </motion.span>
      </button>

      <AgentDisclosure
        id={contentId}
        role="region"
        aria-labelledby={triggerId}
        open={currentOpen}
      >
        <div
          ref={viewportRef}
          className="scrollbar-hide overflow-y-auto px-2 pb-2"
          style={{ maxHeight }}
        >
          {items.length ? (
            <ol aria-live="polite" className="space-y-0">
            <AnimatePresence initial={false} mode="popLayout">
              {items.map((item) => {
                const status = item.status ?? "pending";
                return (
                  <motion.li
                    layout="position"
                    key={item.id}
                    initial={reduce ? { opacity: 1 } : { opacity: 0, y: 6 }}
                    animate={{ opacity: 1, y: 0 }}
                    exit={reduce ? { opacity: 0 } : { opacity: 0, y: -3 }}
                    transition={
                      reduce
                        ? { duration: 0 }
                        : {
                            opacity: { duration: 0.18, ease: EASE_OUT },
                            y: SPRING_LAYOUT,
                            layout: SPRING_LAYOUT,
                          }
                    }
                    className="flex min-h-9 items-center gap-2.5 rounded-xl px-1.5 py-1"
                  >
                    <TodoStatusIcon status={status} progress={item.progress} />
                    <span className="sr-only">{statusLabel(status)}: </span>
                    <span
                      className={cn(
                        "min-w-0 flex-1 truncate text-sm leading-5",
                        status === "pending" && "text-muted-foreground/65",
                        status === "in-progress" && "text-foreground",
                        status === "completed" && "text-muted-foreground/60",
                        status === "cancelled" && "text-muted-foreground/55",
                      )}
                    >
                      <span className="relative inline-block max-w-full">
                        {item.title}
                        <motion.span
                          aria-hidden="true"
                          initial={false}
                          animate={{
                            scaleX: status === "completed" ? 1 : 0,
                            opacity: status === "completed" ? 1 : 0,
                          }}
                          transition={
                            reduce
                              ? { duration: 0 }
                              : { duration: 0.28, ease: EASE_OUT, delay: 0.06 }
                          }
                          className="absolute inset-x-0 top-1/2 h-px origin-left bg-current"
                        />
                      </span>
                    </span>
                    {item.detail ? (
                      <span className="shrink-0 text-sm text-muted-foreground/55">
                        {item.detail}
                      </span>
                    ) : null}
                  </motion.li>
                );
              })}
            </AnimatePresence>
            </ol>
          ) : (
            <p className="px-1.5 py-2 text-sm text-muted-foreground">
              No tasks yet
            </p>
          )}
        </div>
      </AgentDisclosure>
    </section>
  );
}

"use client";

import { motion, type HTMLMotionProps, useReducedMotion } from "motion/react";
import type { CSSProperties } from "react";
import { EASE_OUT } from "@/lib/ease";
import { cn } from "@/lib/utils";

export interface AgentDisclosureProps
  extends Omit<HTMLMotionProps<"div">, "animate" | "initial"> {
  open: boolean;
  openHeight?: CSSProperties["height"];
}

/** Shared transform-only reveal for collapsible agent content. */
export function AgentDisclosure({
  open,
  openHeight = "auto",
  className,
  style,
  transition,
  ...props
}: AgentDisclosureProps) {
  const reduce = useReducedMotion() ?? false;

  return (
    <motion.div
      {...props}
      aria-hidden={!open}
      inert={!open}
      initial={false}
      animate={
        reduce
          ? { opacity: open ? 1 : 0 }
          : {
              opacity: open ? 1 : 0,
              clipPath: open ? "inset(0 0 0% 0)" : "inset(0 0 100% 0)",
              y: open ? 0 : -4,
            }
      }
      transition={
        transition ?? {
          duration: reduce ? 0 : open ? 0.22 : 0.14,
          ease: EASE_OUT,
        }
      }
      className={cn("overflow-hidden", className)}
      style={{
        ...style,
        height: open ? openHeight : 0,
        pointerEvents: open ? undefined : "none",
        transformOrigin: "top",
      }}
    />
  );
}

"use client";

import {
  ActionSwapButton,
  ActionSwapIcon,
  ActionSwapText,
  type ActionSwapButtonProps,
  type ActionSwapIconProps,
  type ActionSwapTextProps,
} from "./action-swap";

export type {
  ActionSwapButtonSize,
  ActionSwapButtonVariant,
  ActionSwapItem,
} from "./action-swap";

export type ActionSwapRollButtonProps = Omit<ActionSwapButtonProps, "animation">;
export type ActionSwapRollTextProps = Omit<ActionSwapTextProps, "animation">;
export type ActionSwapRollIconProps = Omit<ActionSwapIconProps, "animation">;

export function ActionSwapRollButton(props: ActionSwapRollButtonProps) {
  return <ActionSwapButton {...props} animation="roll" />;
}

export function ActionSwapRollText(props: ActionSwapRollTextProps) {
  return <ActionSwapText {...props} animation="roll" />;
}

export function ActionSwapRollIcon(props: ActionSwapRollIconProps) {
  return <ActionSwapIcon {...props} animation="roll" />;
}

"use client";

import { AnimatePresence, type HTMLMotionProps, motion, useReducedMotion, type Variants } from "motion/react";
import type { ReactNode } from "react";
import { useState } from "react";
import { EASE_OUT, SPRING_LAYOUT, SPRING_PRESS, SPRING_SWAP } from "@/lib/ease";
import { cn } from "@/lib/utils";

export type ActionSwapItem = {
  id: string;
  label: ReactNode;
  icon?: ReactNode;
  ariaLabel?: string;
};

export type ActionSwapButtonVariant = "primary" | "secondary" | "outline" | "ghost";
export type ActionSwapButtonSize = "sm" | "md" | "lg" | "icon";
export type ActionSwapAnimation = "blur" | "roll" | "cascade";

/** Animations with a single-element variant set (cascade animates per letter). */
type CoreAnimation = "blur" | "roll";

export interface ActionSwapButtonProps extends Omit<
  HTMLMotionProps<"button">,
  "children" | "onChange"
> {
  items: ActionSwapItem[];
  value?: string;
  defaultValue?: string;
  onValueChange?: (value: string, item: ActionSwapItem) => void;
  variant?: ActionSwapButtonVariant;
  size?: ActionSwapButtonSize;
  animation?: ActionSwapAnimation;
  iconOnly?: boolean;
  cycle?: boolean;
}

export interface ActionSwapTextProps {
  value: string;
  children: ReactNode;
  animation?: ActionSwapAnimation;
  className?: string;
}

export interface ActionSwapIconProps {
  value: string;
  children: ReactNode;
  animation?: ActionSwapAnimation;
  className?: string;
}

// The arriving layer springs in, so a second press mid-swap bends it toward
// the new target instead of restarting. The leaving layer is a little quicker,
// still long enough to cross the arrival so the swap reads as one morph.
const BLUR_TRANSITION = SPRING_SWAP;
const BLUR_EXIT_TRANSITION = { duration: 0.16, ease: EASE_OUT } as const;
const ROLL_TRANSITION = SPRING_SWAP;
const ROLL_EXIT_TRANSITION = { duration: 0.14, ease: EASE_OUT } as const;
// A light blur softens the crossing without smearing small glyphs.
const SWAP_BLUR = "blur(2px)";
const ROLL_BLUR = "blur(3px)";

// Cascade rolls the label one letter at a time, left to right. The leaving
// and landing strings overlap as independent layers (no shared cells), so
// proportional glyph widths never jitter. Exits cascade at half the enter
// stagger so the tail of the old label lingers briefly.
const CASCADE_STAGGER = 0.025;

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 TEXT_VARIANTS: Record<CoreAnimation, Variants> = {
  blur: {
    initial: { opacity: 0, scale: 0.9, filter: SWAP_BLUR },
    animate: {
      opacity: 1,
      scale: 1,
      filter: "blur(0px)",
      transition: BLUR_TRANSITION,
    },
    exit: {
      opacity: 0,
      scale: 0.96,
      filter: SWAP_BLUR,
      transition: BLUR_EXIT_TRANSITION,
    },
  },
  roll: {
    initial: { opacity: 0, y: "90%", filter: ROLL_BLUR },
    animate: {
      opacity: 1,
      y: "0%",
      filter: "blur(0px)",
      transition: ROLL_TRANSITION,
    },
    exit: {
      opacity: 0,
      y: "-90%",
      filter: ROLL_BLUR,
      transition: ROLL_EXIT_TRANSITION,
    },
  },
};

const ICON_VARIANTS: Record<CoreAnimation, Variants> = {
  blur: {
    initial: { opacity: 0, scale: 0.25, filter: SWAP_BLUR },
    animate: {
      opacity: 1,
      scale: 1,
      filter: "blur(0px)",
      transition: BLUR_TRANSITION,
    },
    exit: {
      opacity: 0,
      scale: 0.25,
      filter: SWAP_BLUR,
      transition: BLUR_EXIT_TRANSITION,
    },
  },
  roll: {
    initial: { opacity: 0, y: 12, filter: ROLL_BLUR },
    animate: {
      opacity: 1,
      y: 0,
      filter: "blur(0px)",
      transition: ROLL_TRANSITION,
    },
    exit: {
      opacity: 0,
      y: -12,
      filter: ROLL_BLUR,
      transition: ROLL_EXIT_TRANSITION,
    },
  },
};

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

const SIZE_CLASS: Record<ActionSwapButtonSize, string> = {
  sm: "h-8 gap-1.5 rounded-full px-3 text-xs",
  md: "h-10 gap-2 rounded-full px-4 text-sm",
  lg: "h-12 gap-2.5 rounded-full px-5 text-base",
  icon: "h-10 w-10 rounded-full",
};

export function ActionSwapText({
  value,
  children,
  animation = "blur",
  className,
}: ActionSwapTextProps) {
  const reduce = useReducedMotion();

  // Cascade needs a plain string to split into letters; non-string content
  // and reduced motion fall back to the closest single-element animation.
  const label = typeof children === "string" ? children : null;
  const cascade = animation === "cascade" && label !== null && !reduce;
  const coreAnimation: CoreAnimation =
    animation === "cascade" ? "roll" : animation;

  return (
    <span
      className={cn(
        "relative -my-[0.08em] inline-block max-w-full whitespace-nowrap py-[0.08em] align-bottom",
        className,
      )}
      style={{
        clipPath: "inset(0 -999px)",
        WebkitClipPath: "inset(0 -999px)",
      }}
    >
      <span
        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 ? (
        <>
          {/* Letters are decorative fragments; readers get the whole label. */}
          <span className="sr-only">{label}</span>
          <AnimatePresence initial={false}>
            <motion.span
              key={`cascade-${value}`}
              aria-hidden
              initial="initial"
              animate="animate"
              exit="exit"
              className="absolute left-0 top-[0.08em] inline-block whitespace-pre"
            >
              {label.split("").map((char, i) => (
                <motion.span
                  // biome-ignore lint/suspicious/noArrayIndexKey: position is the slot identity — the letter at a position is exactly what rolls.
                  key={i}
                  custom={i * CASCADE_STAGGER}
                  variants={CASCADE_LETTER_VARIANTS}
                  // Own states: a label that swaps away and straight back
                  // re-enters mid-exit, and only owned targets are restored.
                  initial="initial"
                  animate="animate"
                  exit="exit"
                  className="inline-block whitespace-pre will-change-[opacity,filter,transform]"
                >
                  {char}
                </motion.span>
              ))}
            </motion.span>
          </AnimatePresence>
        </>
      ) : (
        <AnimatePresence initial={false}>
          <motion.span
            key={`${animation}-${value}`}
            variants={TEXT_VARIANTS[coreAnimation]}
            initial={reduce ? false : "initial"}
            animate={reduce ? { opacity: 1, filter: "blur(0px)", scale: 1, y: 0 } : "animate"}
            exit={reduce ? undefined : "exit"}
            // Truncation lives on the layer that holds the text — the layer
            // moves as a whole, so clipping it never eats the roll.
            className="absolute left-0 top-[0.08em] inline-block max-w-full truncate will-change-[opacity,filter,transform]"
          >
            {children}
          </motion.span>
        </AnimatePresence>
      )}
    </span>
  );
}

export function ActionSwapIcon({
  value,
  children,
  animation = "blur",
  className,
}: ActionSwapIconProps) {
  const reduce = useReducedMotion();
  // Icons are single elements — cascade maps to its closest motion, roll.
  const coreAnimation: CoreAnimation =
    animation === "cascade" ? "roll" : animation;

  return (
    <span className={cn("relative inline-grid shrink-0 place-items-center overflow-hidden", className)}>
      <AnimatePresence mode="popLayout" initial={false}>
        <motion.span
          key={`${animation}-${value}`}
          aria-hidden
          variants={ICON_VARIANTS[coreAnimation]}
          initial={reduce ? false : "initial"}
          animate={reduce ? { opacity: 1, filter: "blur(0px)", scale: 1, y: 0 } : "animate"}
          exit={reduce ? undefined : "exit"}
          className="col-start-1 row-start-1 inline-flex items-center justify-center will-change-[opacity,filter,transform]"
        >
          {children}
        </motion.span>
      </AnimatePresence>
    </span>
  );
}

export function ActionSwapButton({
  items,
  value,
  defaultValue,
  onValueChange,
  variant = "secondary",
  size = "md",
  animation = "blur",
  iconOnly = size === "icon",
  cycle = true,
  className,
  disabled,
  onClick,
  style,
  ...rest
}: ActionSwapButtonProps) {
  const reduce = useReducedMotion();
  const [internalValue, setInternalValue] = useState(defaultValue ?? items[0]?.id);
  const currentValue = value ?? internalValue;
  const activeIndex = Math.max(0, items.findIndex((item) => item.id === currentValue));
  const activeItem = items[activeIndex] ?? items[0];
  const hasIcon = items.some((item) => item.icon);
  const nextItem = cycle && items.length > 0 ? items[(activeIndex + 1) % items.length] : undefined;

  if (!activeItem) return null;

  const accessibleLabel = activeItem.ariaLabel ?? (iconOnly && typeof activeItem.label === "string" ? activeItem.label : undefined);
  const layoutTransition = reduce ? { duration: 0 } : SPRING_LAYOUT;

  return (
    <motion.button
      type="button"
      disabled={disabled}
      // A label of a different length resizes the button: glide the width on
      // the soft layout spring, and only when the value changes, so unrelated
      // page reflow never animates the button.
      layout
      layoutDependency={activeItem.id}
      whileTap={reduce || disabled ? undefined : { scale: 0.97 }}
      transition={{ ...SPRING_PRESS, layout: layoutTransition }}
      // Layout animations only correct a radius set inline.
      style={{ borderRadius: 9999, ...style }}
      className={cn(
        "inline-flex items-center justify-center overflow-hidden font-medium transition-colors",
        "disabled:pointer-events-none disabled:opacity-50",
        VARIANT_CLASS[variant],
        SIZE_CLASS[size],
        className,
      )}
      aria-label={accessibleLabel}
      onClick={(event) => {
        onClick?.(event);
        if (event.defaultPrevented || disabled || !cycle || !nextItem) return;
        if (value === undefined) setInternalValue(nextItem.id);
        onValueChange?.(nextItem.id, nextItem);
      }}
      {...rest}
    >
      {/* Position-only layout keeps the contents from stretching with the
          button while its width glides. */}
      {hasIcon ? (
        <motion.span
          layout="position"
          layoutDependency={activeItem.id}
          transition={layoutTransition}
          className="inline-flex shrink-0"
        >
          <ActionSwapIcon value={activeItem.id} animation={animation} className="h-4 w-4">
            {activeItem.icon ?? null}
          </ActionSwapIcon>
        </motion.span>
      ) : null}
      {!iconOnly ? (
        <motion.span
          layout="position"
          layoutDependency={activeItem.id}
          transition={layoutTransition}
          className="inline-flex min-w-0 max-w-full"
        >
          <ActionSwapText value={activeItem.id} animation={animation}>
            {activeItem.label}
          </ActionSwapText>
        </motion.span>
      ) : null}
    </motion.button>
  );
}