Animated Breadcrumb

// 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;
/** Accelerating curve for things that fall (a dropped ball, a toppled block). Not for UI entrances. */
export const EASE_IN = [0.55, 0, 1, 0.45] 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";

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";

import {
  createContext,
  type ReactNode,
  useCallback,
  useContext,
  useMemo,
} from "react";

/**
 * A component's messages. Plain strings with `{name}` placeholders, so a
 * dictionary stays JSON-serializable and can be passed from a server layout.
 * There are no plural forms: write messages that read correctly for any count.
 */
export type Messages = Record<string, string>;

/** A language file: component namespace → any subset of that component's messages. */
export type LocaleMessages = Record<string, Partial<Messages>>;

type LocaleContextValue = {
  locale?: string;
  messages: LocaleMessages;
};

const NO_MESSAGES: LocaleMessages = {};

const LocaleContext = createContext<LocaleContextValue>({ messages: NO_MESSAGES });

/** Without a locale, digits stay plain so server and client render the same text. */
export function formatNumber(value: number, locale?: string) {
  return locale ? new Intl.NumberFormat(locale).format(value) : String(value);
}

export interface LocaleProviderProps {
  /** BCP 47 tag, e.g. `de`, `pt-BR`. Drives `Intl` number formatting. */
  locale: string;
  /**
   * Component namespace → translated strings. Missing keys fall back to English.
   * Pass a stable object (a module constant, imported JSON or a memoized value):
   * a new object each render gives every translated component a new `t`.
   */
  messages?: LocaleMessages;
  children: ReactNode;
}

export function LocaleProvider({ locale, messages = NO_MESSAGES, children }: LocaleProviderProps) {
  const value = useMemo(() => ({ locale, messages }), [locale, messages]);
  return <LocaleContext.Provider value={value}>{children}</LocaleContext.Provider>;
}

export function useLocale(): { locale?: string } {
  return { locale: useContext(LocaleContext).locale };
}

/**
 * Resolves a component's strings: `labels` prop, then the provider's
 * messages for `namespace`, then the component's English `defaults`.
 * Numbers passed as values are formatted for the provider's locale.
 */
export function useMessages<T extends Messages>(
  namespace: string,
  defaults: T,
  labels?: Partial<T>,
) {
  const { locale, messages } = useContext(LocaleContext);
  const provided = messages[namespace];
  // Inline `labels={{ … }}` is a new object every render. Keying it by content
  // keeps `t` one identity until a label changes, so effects and memos that
  // depend on `t` don't re-run per render, and render-time reads never lag.
  const labelsKey = labels ? JSON.stringify(labels) : "";
  const stableLabels = useMemo(
    () => (labelsKey ? (JSON.parse(labelsKey) as Partial<T>) : undefined),
    [labelsKey],
  );

  return useCallback(
    (key: keyof T & string, values?: Record<string, string | number>) => {
      const template = stableLabels?.[key] ?? provided?.[key] ?? defaults[key];
      if (!values) return template;
      return template.replace(/\{(\w+)\}/g, (match, name: string) => {
        const value = values[name];
        if (value === undefined) return match;
        return typeof value === "number" ? formatNumber(value, locale) : value;
      });
    },
    [defaults, stableLabels, locale, provided],
  );
}

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

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

/**
 * Elements that can usually take keyboard focus. The selector cannot see
 * everything focus() checks (an element under `display: none`, say), so a
 * caller that needs certainty tries focus() and checks where it landed.
 */
export const FOCUSABLE_SELECTOR = [
  "a[href]",
  "button:not(:disabled)",
  "input:not(:disabled):not([type='hidden'])",
  "select:not(:disabled)",
  "textarea:not(:disabled)",
  "[tabindex]:not([tabindex='-1'])",
].join(",");

"use client";
// beui.dev/components/motion/breadcrumb

import { ChevronRight, Ellipsis } from "lucide-react";
import {
  AnimatePresence,
  LayoutGroup,
  motion,
  useIsPresent,
  useReducedMotion,
  type HTMLMotionProps,
} from "motion/react";
import {
  Children,
  createContext,
  useContext,
  forwardRef,
  useEffect,
  useLayoutEffect,
  useRef,
  useState,
  type ReactNode,
  useId,
  type ComponentPropsWithRef,
  type ReactElement,
} from "react";
import { MorphPopover, MorphPopoverContent, MorphPopoverTrigger } from "@/components/motion/popover-morph";
import { useHoverCapable } from "@/lib/hooks/use-hover-capable";
import { EASE_OUT, SPRING_LAYOUT } from "@/lib/ease";
import { useMessages } from "@/lib/i18n";
import { cn } from "@/lib/utils";

/** English defaults. Override per instance with `labels`, or app-wide with `LocaleProvider`. */
export const breadcrumbMessages = {
  label: "Breadcrumb",
  showHidden: "Show hidden paths",
};

export type BreadcrumbMessages = typeof breadcrumbMessages;

const BreadcrumbLabels = createContext<Partial<BreadcrumbMessages> | undefined>(undefined);

function useBreadcrumbMessages() {
  return useMessages("breadcrumb", breadcrumbMessages, useContext(BreadcrumbLabels));
}

export type BreadcrumbProps = ComponentPropsWithRef<"nav"> & {
  /** Override any built-in string. */
  labels?: Partial<BreadcrumbMessages>;
};

/** A navigation landmark. Keep it mounted while the route changes. */
export function Breadcrumb({ className, children, labels, ...props }: BreadcrumbProps) {
  const id = useId();
  const t = useMessages("breadcrumb", breadcrumbMessages, labels);
  return (
    <nav aria-label={t("label")} {...props} className={cn("min-w-0", className)}>
      <BreadcrumbLabels.Provider value={labels}>
        <LayoutGroup id={id}>{children}</LayoutGroup>
      </BreadcrumbLabels.Provider>
    </nav>
  );
}

export type BreadcrumbListProps = ComponentPropsWithRef<"ol"> & {
  /** Maximum visible slots, including the ellipsis. Minimum 3; Infinity disables collapsing. */
  maxItems?: number;
  /** Accessible label for the hidden ancestor disclosure. */
  overflowLabel?: string;
};

/** Pass keyed BreadcrumbItems directly so entering and leaving routes animate. */
export function BreadcrumbList({ className, children, maxItems = 4, overflowLabel, ...props }: BreadcrumbListProps) {
  const items = Children.toArray(children);
  const limit = Number.isFinite(maxItems) ? Math.max(3, Math.floor(maxItems)) : 4;
  const collapse = maxItems !== Infinity && items.length > limit;
  const tailCount = limit - 2;
  const visible = collapse ? [
    items[0],
    <BreadcrumbItem key="breadcrumb-overflow">
      <BreadcrumbSeparator />
      <BreadcrumbEllipsis label={overflowLabel}>
        {items.slice(1, -tailCount)}
      </BreadcrumbEllipsis>
    </BreadcrumbItem>,
    ...items.slice(-tailCount),
  ] : items;
  return (
    <ol
      {...props}
      className={cn("relative flex flex-wrap items-center gap-x-1 gap-y-1 text-sm", className)}
    >
      <AnimatePresence initial={false} mode="popLayout">{visible}</AnimatePresence>
    </ol>
  );
}

export type BreadcrumbItemProps = HTMLMotionProps<"li">;

/** Use a stable route key; put its optional separator inside this item. */
export const BreadcrumbItem = forwardRef<HTMLLIElement, BreadcrumbItemProps>(
  function BreadcrumbItem({ className, style, children, ...props }, ref) {
    const reduce = useReducedMotion();
    const present = useIsPresent();
    const itemRef = useRef<HTMLLIElement>(null);
    useLayoutEffect(() => {
      const item = itemRef.current;
      if (!item || !present) return;
      const measure = () => {
        // popLayout snapshots offsetWidth (integer pixels). Retain the exact
        // width so a fractional-pixel loss cannot wrap the final character.
        item.style.setProperty("--breadcrumb-exit-width", `${item.getBoundingClientRect().width}px`);
      };
      measure();
      const observer = new ResizeObserver(measure);
      observer.observe(item);
      return () => observer.disconnect();
    }, [present]);
    const hidden = { opacity: 0, y: reduce ? 0 : 6 };
    return (
      <motion.li
        ref={(node) => {
          itemRef.current = node;
          if (typeof ref === "function") return ref(node);
          if (ref) ref.current = node;
        }}
        layout={reduce ? false : "position"}
        initial={hidden}
        animate={{ opacity: 1, y: 0 }}
        exit={hidden}
        transition={{ duration: 0.2, ease: EASE_OUT, layout: SPRING_LAYOUT }}
        {...props}
        inert={!present}
        aria-hidden={!present || undefined}
        style={{
          ...style,
          minWidth: present ? style?.minWidth : "var(--breadcrumb-exit-width)",
          pointerEvents: present ? style?.pointerEvents : "none",
        }}
        className={cn("relative inline-flex min-w-0 max-w-full items-center gap-1", className)}
      >
        {children}
      </motion.li>
    );
  },
);

export type BreadcrumbLinkProps = ComponentPropsWithRef<"a"> & {
  /** Render your router's Link, spreading these props onto it. */
  render?: (props: ComponentPropsWithRef<"a">) => ReactElement;
};

export function BreadcrumbLink({ className, render, ...props }: BreadcrumbLinkProps) {
  const linkProps = {
    ...props,
    className: cn(
      "inline-flex min-h-8 min-w-0 items-center gap-1.5 rounded-md px-2 font-medium text-muted-foreground transition-colors duration-150 hover:bg-muted/60 hover:text-foreground focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-ring focus-visible:ring-offset-2 [&>svg]:size-3.5 [&>svg]:shrink-0",
      className,
    ),
  };
  return render ? render(linkProps) : <a {...linkProps} />;
}

export type BreadcrumbPageProps = ComponentPropsWithRef<"span">;

export function BreadcrumbPage({ className, children, ...props }: BreadcrumbPageProps) {
  return (
    <span
      {...props}
      aria-current="page"
      className={cn(
        "relative isolate inline-flex min-h-8 min-w-0 items-center gap-1.5 rounded-md px-2 font-medium text-foreground [overflow-wrap:anywhere] focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-ring [&>svg]:size-3.5 [&>svg]:shrink-0",
        className,
      )}
    >
      {children}
    </span>
  );
}

export type BreadcrumbSeparatorProps = ComponentPropsWithRef<"span">;

/** Decorative separator, placed inside the following BreadcrumbItem. */
export function BreadcrumbSeparator({ className, children, ...props }: BreadcrumbSeparatorProps) {
  return (
    <span
      {...props}
      aria-hidden="true"
      data-breadcrumb-separator=""
      className={cn("inline-flex shrink-0 items-center text-muted-foreground/50 [&>svg]:size-3.5 rtl:rotate-180", className)}
    >
      {children ?? <ChevronRight />}
    </span>
  );
}


export interface BreadcrumbEllipsisProps {
  /** Hidden BreadcrumbItems, in path order. */
  children: ReactNode;
  className?: string;
  label?: string;
}

/** Hover disclosure with click/touch toggle and keyboard access to ancestor links. */
export function BreadcrumbEllipsis({ children, className, label }: BreadcrumbEllipsisProps) {
  const t = useBreadcrumbMessages();
  const [open, setOpen] = useState(false);
  const [placement, setPlacement] = useState<{ align: "start" | "end"; side: "top" | "bottom"; width: number }>({ align: "start", side: "bottom", width: 224 });
  const canHover = useHoverCapable();
  const present = useIsPresent();
  const trigger = useRef<HTMLButtonElement>(null);
  const panel = useRef<HTMLOListElement>(null);
  const focusOnOpen = useRef(false);
  const closeTimer = useRef<ReturnType<typeof setTimeout> | null>(null);

  useLayoutEffect(() => {
    if (!open) return;
    const update = () => {
      const rect = trigger.current?.getBoundingClientRect();
      if (!rect) return;
      const right = window.innerWidth - rect.left - 8;
      const left = rect.right - 8;
      const align = right < 224 && left > right ? "end" : "start";
      const below = window.innerHeight - rect.bottom;
      setPlacement({
        align,
        side: below < 280 && rect.top > below ? "top" : "bottom",
        width: Math.max(32, Math.min(224, align === "start" ? right : left)),
      });
    };
    update();
    window.addEventListener("resize", update);
    return () => window.removeEventListener("resize", update);
  }, [open]);

  const cancelClose = () => {
    if (closeTimer.current !== null) clearTimeout(closeTimer.current);
    closeTimer.current = null;
  };
  const leave = () => {
    cancelClose();
    // Allow the pointer to cross the gap between the trigger and portal.
    closeTimer.current = setTimeout(() => {
      if (!panel.current?.contains(document.activeElement) && document.activeElement !== trigger.current) setOpen(false);
    }, 160);
  };
  useEffect(() => () => {
    if (closeTimer.current !== null) clearTimeout(closeTimer.current);
  }, []);

  useEffect(() => {
    if (!open) return;
    const onFocus = (event: FocusEvent) => {
      if (event.target instanceof Node && event.target !== trigger.current && !panel.current?.contains(event.target)) setOpen(false);
    };
    document.addEventListener("focusin", onFocus);
    return () => document.removeEventListener("focusin", onFocus);
  }, [open]);

  return (
    <MorphPopover open={open && present} onOpenChange={setOpen} className={cn(className)}>
      <span
        onPointerEnter={(event) => {
          cancelClose();
          if (canHover && event.pointerType === "mouse") {
            focusOnOpen.current = false;
            setOpen(true);
          }
        }}
        onPointerLeave={leave}
      >
        <MorphPopoverTrigger>
          <button
            ref={trigger}
            type="button"
            aria-label={label ?? t("showHidden")}
            className="inline-flex size-8 items-center justify-center rounded-md text-muted-foreground transition-colors hover:bg-muted/60 hover:text-foreground focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-ring"
            // Enter and Space open through MorphPopoverTrigger, which moves
            // focus to the first path itself. ArrowDown opens without a click.
            onKeyDown={(event) => {
              if (event.key === "ArrowDown") {
                event.preventDefault();
                focusOnOpen.current = true;
                setOpen(true);
                panel.current?.querySelector<HTMLElement>("a[href],button")?.focus();
              }
            }}
          >
            <Ellipsis aria-hidden="true" className="size-4" />
          </button>
        </MorphPopoverTrigger>
        <MorphPopoverContent align={placement.align} side={placement.side} radius={10} sideOffset={6} className="p-1.5">
          <BreadcrumbOverflowPaths
            ref={panel}
            style={{ width: placement.width - 14 }}
            focusOnOpen={focusOnOpen}
            onPointerEnter={() => { cancelClose(); setOpen(true); }}
            onPointerLeave={leave}
            onClick={(event) => {
              if ((event.target as Element).closest("a[href]")) setOpen(false);
            }}
          >
            {children}
          </BreadcrumbOverflowPaths>
        </MorphPopoverContent>
      </span>
    </MorphPopover>
  );
}

function BreadcrumbOverflowPaths({ focusOnOpen, ref, ...props }: ComponentPropsWithRef<"ol"> & { focusOnOpen: { current: boolean } }) {
  const localRef = useRef<HTMLOListElement>(null);
  useLayoutEffect(() => {
    if (!focusOnOpen.current) return;
    const focus = () => localRef.current?.querySelector<HTMLElement>("a[href],button")?.focus();
    focus();
    // The portal becomes visible after its parent's layout measurement.
    const frame = requestAnimationFrame(() => {
      focus();
      focusOnOpen.current = false;
    });
    return () => cancelAnimationFrame(frame);
  }, [focusOnOpen]);
  return (
    <ol
      {...props}
      ref={(node) => {
        localRef.current = node;
        if (typeof ref === "function") return ref(node);
        if (ref) ref.current = node;
      }}
      className="flex max-h-64 flex-col gap-0.5 overflow-y-auto [&>li]:w-full [&_a]:w-full [&_a]:py-1 [&_a]:[overflow-wrap:anywhere] [&_[data-breadcrumb-separator]]:hidden"
    />
  );
}

"use client";

import {
  AnimatePresence,
  animate,
  motion,
  useMotionValue,
  usePresence,
  useReducedMotion,
  useTransform,
} from "motion/react";
import {
  cloneElement,
  createContext,
  isValidElement,
  type ReactElement,
  type ReactNode,
  type Ref,
  type RefObject,
  useCallback,
  useContext,
  useEffect,
  useId,
  useLayoutEffect,
  useMemo,
  useRef,
  useState,
} from "react";
import { createPortal } from "react-dom";
import { usePopoverPortalPosition } from "@/components/motion/popover-position";
import { EASE_OUT } from "@/lib/ease";
import { FOCUSABLE_SELECTOR } from "@/lib/focusable";
import { cn } from "@/lib/utils";

type Side = "top" | "bottom";
type Align = "start" | "end";

type MorphContextValue = {
  open: boolean;
  setOpen: (open: boolean) => void;
  toggle: () => void;
  triggerId: string;
  contentId: string;
  /** The element the panel measures against — see `registerTrigger`. */
  triggerRef: React.MutableRefObject<HTMLElement | null>;
  registerTrigger: (node: HTMLElement | null) => void;
  contentRef: React.MutableRefObject<HTMLDivElement | null>;
  /** Arms or disarms moving focus into the panel as it next appears. */
  armFocusOnOpen: (armed: boolean) => void;
  /** Reads and disarms the flag set by `armFocusOnOpen`. */
  takeFocusOnOpen: () => boolean;
};

const MorphContext = createContext<MorphContextValue | null>(null);

function useMorphContext(component: string) {
  const ctx = useContext(MorphContext);
  if (!ctx) throw new Error(`${component} must be used within <MorphPopover>`);
  return ctx;
}

export interface MorphPopoverProps {
  children: ReactNode;
  /** Controlled open state. */
  open?: boolean;
  /** Uncontrolled initial open state. */
  defaultOpen?: boolean;
  onOpenChange?: (open: boolean) => void;
  className?: string;
}

/**
 * A popover whose full-size panel reveals from the corner nearest the trigger
 * on one spring, then retraces the same clip on close. Content and surface
 * edges keep their size throughout. Closes on outside pointer / Escape.
 * Controlled or uncontrolled.
 */
export function MorphPopover({
  children,
  open: controlledOpen,
  defaultOpen = false,
  onOpenChange,
  className,
}: MorphPopoverProps) {
  const baseId = useId();
  const [root, setRoot] = useState<HTMLDivElement | null>(null);
  const [trigger, setTrigger] = useState<HTMLElement | null>(null);
  const contentRef = useRef<HTMLDivElement | null>(null);
  const [internalOpen, setInternalOpen] = useState(defaultOpen);
  const controlled = controlledOpen !== undefined;
  const open = controlled ? controlledOpen : internalOpen;

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

  // A keyboard open arms focus for the panel to take as it appears. Any later
  // key or pointer press disarms it, so an open the parent declined cannot
  // leave it armed for a later open that nobody asked to focus.
  const focusOnOpenRef = useRef(false);
  const disarmRef = useRef<AbortController | null>(null);
  const armFocusOnOpen = useCallback((armed: boolean) => {
    disarmRef.current?.abort();
    disarmRef.current = null;
    focusOnOpenRef.current = armed;
    if (!armed) return;
    const controller = new AbortController();
    const disarm = () => {
      focusOnOpenRef.current = false;
      controller.abort();
    };
    const options = { capture: true, signal: controller.signal };
    document.addEventListener("keydown", disarm, options);
    document.addEventListener("pointerdown", disarm, options);
    disarmRef.current = controller;
  }, []);
  const takeFocusOnOpen = useCallback(() => {
    const armed = focusOnOpenRef.current;
    armFocusOnOpen(false);
    return armed;
  }, [armFocusOnOpen]);
  useEffect(() => () => disarmRef.current?.abort(), []);

  // A trigger normally registers itself through MorphPopoverTrigger. It can't
  // when something else already clones the element — a Tooltip wrapping the
  // button, say — and an unregistered trigger leaves the panel with nothing to
  // measure against, so it renders permanently invisible. The root boxes the
  // trigger exactly (the content portals out of it), so it stands in until a
  // real trigger registers, and stands in again if that one unmounts. Both are
  // state, so a trigger arriving while the panel is open re-anchors it.
  const anchorRef = useMemo<React.MutableRefObject<HTMLElement | null>>(
    () => ({ current: trigger ?? root }),
    [root, trigger],
  );

  // The panel is a `role="dialog"` and goes inert the moment it closes, so
  // focus cannot be left sitting inside it: a dismissal hands it back to the
  // trigger, the way the ARIA dialog pattern asks. A pointer dismissal takes
  // the focus onward itself when it lands on something focusable — this only
  // catches the case where it would otherwise be stranded. When no trigger has
  // registered, the root anchor stands in only if it can actually hold focus;
  // there is nowhere better than where the keyboard already is, so leave it.
  const close = useCallback(() => {
    setOpen(false);
    const focused = document.activeElement;
    const inPanel =
      focused instanceof HTMLElement && contentRef.current?.contains(focused);
    if (!inPanel) return;
    const restore = trigger ?? (root && root.tabIndex >= 0 ? root : null);
    restore?.focus();
  }, [root, setOpen, trigger]);

  useEffect(() => {
    if (!open) return;
    const onKey = (e: KeyboardEvent) => e.key === "Escape" && close();
    const onPointer = (e: PointerEvent) => {
      const target = e.target as Node;
      if (
        root &&
        !root.contains(target) &&
        !contentRef.current?.contains(target)
      )
        close();
    };
    window.addEventListener("keydown", onKey);
    window.addEventListener("pointerdown", onPointer);
    return () => {
      window.removeEventListener("keydown", onKey);
      window.removeEventListener("pointerdown", onPointer);
    };
  }, [open, root, close]);

  const ctx = useMemo<MorphContextValue>(
    () => ({
      open,
      setOpen,
      toggle,
      triggerId: `${baseId}-trigger`,
      contentId: `${baseId}-content`,
      triggerRef: anchorRef,
      registerTrigger: setTrigger,
      contentRef,
      armFocusOnOpen,
      takeFocusOnOpen,
    }),
    [open, setOpen, toggle, baseId, anchorRef, armFocusOnOpen, takeFocusOnOpen],
  );

  return (
    <MorphContext.Provider value={ctx}>
      <div ref={setRoot} className={cn("relative inline-flex", className)}>
        {children}
      </div>
    </MorphContext.Provider>
  );
}

export interface MorphPopoverTriggerProps {
  children: ReactElement;
}

function mergeRefs<T>(...refs: Array<Ref<T> | undefined>) {
  return (node: T | null) => {
    for (const ref of refs) {
      if (typeof ref === "function") ref(node);
      else if (ref && typeof ref === "object")
        (ref as React.MutableRefObject<T | null>).current = node;
    }
  };
}

/** Wraps a single element, toggling the popover on click. */
export function MorphPopoverTrigger({ children }: MorphPopoverTriggerProps) {
  const ctx = useMorphContext("MorphPopoverTrigger");
  const child = children as ReactElement<Record<string, unknown>>;
  const childOnClick = child?.props?.onClick as
    | ((e: unknown) => void)
    | undefined;
  const childOnKeyDown = child?.props?.onKeyDown as
    | ((e: unknown) => void)
    | undefined;
  const childOnPointerDown = child?.props?.onPointerDown as
    | ((e: unknown) => void)
    | undefined;
  // Set by an Enter or Space keydown on the trigger, cleared by a pointer
  // press, read by the click that follows.
  const keyboardRef = useRef(false);
  const childRef = (child?.props as { ref?: Ref<HTMLElement> } | undefined)
    ?.ref;
  // Register once per actual ref change, not once per open-state render.
  const mergedRef = useMemo(
    () => mergeRefs(childRef, ctx.registerTrigger),
    [childRef, ctx.registerTrigger],
  );
  if (!isValidElement(children)) return children;

  return cloneElement(child, {
    id: ctx.triggerId,
    ref: mergedRef,
    onKeyDown: (e: unknown) => {
      childOnKeyDown?.(e);
      const key = (e as { key?: string } | undefined)?.key;
      keyboardRef.current = key === "Enter" || key === " ";
    },
    onPointerDown: (e: unknown) => {
      childOnPointerDown?.(e);
      keyboardRef.current = false;
    },
    onClick: (e: unknown) => {
      childOnClick?.(e);
      // Enter and Space reach here as a click with `detail` 0 after their
      // keydown on this element. A pointer click counts at least 1, and a
      // scripted click() has no keydown before it. Only a keyboard open
      // moves focus into the panel.
      const keyboard =
        keyboardRef.current &&
        (e as { detail?: number } | undefined)?.detail === 0;
      keyboardRef.current = false;
      ctx.armFocusOnOpen(!ctx.open && keyboard);
      ctx.toggle();
    },
    "aria-haspopup": "dialog",
    "aria-expanded": ctx.open,
    "aria-controls": ctx.open ? ctx.contentId : undefined,
  });
}

// Full-distance clip travel needs a shorter curve than SPRING_PANEL's slow
// overdamped tail. A non-bouncing spring reaches its rest within 260 ms.
const MORPH_ENTER = { type: "spring", duration: 0.26, bounce: 0 } as const;
const MORPH_EXIT = { duration: 0.2, ease: EASE_OUT } as const;

// Keep the panel and content at their final size. An inset clip reveals the
// nearest corner without scaling borders, shadows or keyboard-focus geometry.
// A full-size clip keeps content at its final coordinates without box-to-box
// scale correction. One progress value keeps clip and opacity synchronized;
// clip-path and the shadow may paint, so this is not a compositor-only morph.
function clipAt(side: Side, align: Align, radius: number, inset: number) {
  return `inset(${side === "top" ? inset : 0}% ${align === "start" ? inset : 0}% ${side === "bottom" ? inset : 0}% ${align === "end" ? inset : 0}% round ${radius}px)`;
}

export interface MorphPopoverContentProps {
  children: ReactNode;
  side?: Side;
  align?: Align;
  /** Gap between trigger and panel, in px. Default 8. */
  sideOffset?: number;
  /** Panel corner radius, in px. Default 16. */
  radius?: number;
  /** Draw the surface shadow. Default true. */
  shadow?: boolean;
  /**
   * Runs after the portalled surface is positioned and visible. Passing it
   * hands focus to the caller: the panel then moves no focus on its own.
   */
  onOpenAutoFocus?: (content: HTMLDivElement) => void;
  /**
   * Element to focus when the trigger opens the panel by keyboard. Defaults
   * to the first focusable element in the panel, or the panel itself. A
   * pointer open does not move focus. Ignored with `onOpenAutoFocus`.
   */
  initialFocus?: RefObject<HTMLElement | null>;
  className?: string;
}

export function MorphPopoverContent(props: MorphPopoverContentProps) {
  const ctx = useMorphContext("MorphPopoverContent");
  const [portalReady, setPortalReady] = useState(false);
  useEffect(() => setPortalReady(true), []);
  if (!portalReady) return null;
  return createPortal(
    <AnimatePresence>
      {ctx.open && <MorphPopoverSurface {...props} />}
    </AnimatePresence>,
    document.body,
  );
}

// Measurement belongs to the mounted portal session: reopening must not start
// an entrance at the previous session's coordinates before measuring this one.
function MorphPopoverSurface({
  children,
  side = "bottom",
  align = "end",
  sideOffset = 8,
  radius = 16,
  shadow = true,
  onOpenAutoFocus,
  initialFocus,
  className,
}: MorphPopoverContentProps) {
  const ctx = useMorphContext("MorphPopoverContent");
  const reduce = useReducedMotion() ?? false;
  const [isPresent, safeToRemove] = usePresence();
  const layout = usePopoverPortalPosition(
    ctx.triggerRef,
    ctx.contentRef,
    isPresent,
  );

  const preferredLeft = layout
    ? align === "end"
      ? layout.trigger.left + layout.trigger.width - layout.content.width
      : layout.trigger.left
    : 0;
  // Keep larger compositions, such as calendars, inside the viewport. Prefer
  // the requested side, then use the roomier side when it cannot fit there.
  const gutter = 12;
  const below = layout
    ? Math.max(
        0,
        window.innerHeight -
          layout.trigger.top -
          layout.trigger.height -
          sideOffset -
          gutter,
      )
    : 0;
  const above = layout
    ? Math.max(0, layout.trigger.top - sideOffset - gutter)
    : 0;
  const requestedSpace = side === "bottom" ? below : above;
  const otherSpace = side === "bottom" ? above : below;
  const resolvedSide =
    layout &&
    layout.content.height > requestedSpace &&
    otherSpace > requestedSpace
      ? side === "bottom"
        ? "top"
        : "bottom"
      : side;
  const availableHeight = resolvedSide === "bottom" ? below : above;
  const left = layout
    ? Math.max(
        gutter,
        Math.min(
          preferredLeft,
          window.innerWidth - layout.content.width - gutter,
        ),
      )
    : 0;
  const top = layout
    ? resolvedSide === "bottom"
      ? layout.trigger.top + layout.trigger.height + sideOffset
      : Math.max(
          gutter,
          layout.trigger.top - layout.content.height - sideOffset,
        )
    : 0;

  const progress = useMotionValue(0);
  const clipPath = useTransform(progress, (p) =>
    clipAt(resolvedSide, align, radius, 92 * (1 - p)),
  );
  const surfaceOpacity = useTransform(progress, [0, 0.15], [0, 1]);
  // Reduced motion has no travel, so a short fade carries the whole entrance
  // and exit on its own.
  const fade = useMotionValue(reduce ? 0 : 1);
  const ready = layout !== null;
  const focusedOnOpen = useRef(false);
  useEffect(() => {
    if (
      !ready ||
      !isPresent ||
      focusedOnOpen.current ||
      !ctx.contentRef.current
    )
      return;
    focusedOnOpen.current = true;
    onOpenAutoFocus?.(ctx.contentRef.current);
  }, [ready, isPresent, ctx.contentRef, onOpenAutoFocus]);
  // `safeToRemove` is a new function on every render: AnimatePresence
  // rebuilds its context each time its parent renders. Read it through a ref
  // so a render during the exit (a consumer's state change, a list streaming
  // in) does not restart the exit from where it got to — restarted every
  // render, it would close in ever smaller steps and never report completion,
  // leaving an inert, invisible panel mounted for good.
  const safeToRemoveRef = useRef(safeToRemove);
  useLayoutEffect(() => {
    safeToRemoveRef.current = safeToRemove;
  });
  useEffect(() => {
    if (!ready) {
      if (!isPresent) safeToRemoveRef.current?.();
      return;
    }
    const settle = () => {
      if (!isPresent) safeToRemoveRef.current?.();
    };
    if (reduce) {
      progress.jump(1);
      const animation = animate(fade, isPresent ? 1 : 0, {
        duration: 0.12,
        onComplete: settle,
      });
      return () => animation.stop();
    }
    const animation = animate(progress, isPresent ? 1 : 0, {
      ...(isPresent ? MORPH_ENTER : MORPH_EXIT),
      onComplete: settle,
    });
    return () => animation.stop();
  }, [fade, progress, ready, isPresent, reduce]);

  // The wrapper stays `visibility: hidden` until the first measurement, and
  // focus() inside a hidden subtree is silently ignored. So move focus in the
  // commit that makes the panel visible, not when it mounts. A CSS transition
  // on `visibility` can still hold the controls hidden for a moment after
  // that commit (a reduced-motion reset that gives every element a short
  // transition-duration does), so while focus rests on the panel or has not
  // moved, each such transition that ends tries the candidates again, until
  // the user presses a key or pointer. The effect runs once per open, so it
  // reads the caller's props through refs: a new ref or callback passed
  // mid-open must not tear down a pending retry.
  const initialFocusRef = useRef(initialFocus);
  const callerFocusesRef = useRef(onOpenAutoFocus !== undefined);
  useLayoutEffect(() => {
    initialFocusRef.current = initialFocus;
    callerFocusesRef.current = onOpenAutoFocus !== undefined;
  });
  const { contentRef, takeFocusOnOpen } = ctx;
  useLayoutEffect(() => {
    if (!ready || !isPresent) return;
    if (!takeFocusOnOpen() || callerFocusesRef.current) return;
    const panel = contentRef.current;
    const wrapper = panel?.parentElement;
    if (!panel || !wrapper) return;
    const from = document.activeElement;
    const unmoved = () =>
      document.activeElement === from || document.activeElement === panel;
    // The selector also matches elements focus() refuses: a hidden input, a
    // disabled button that carries a tabindex, anything under display: none.
    // Keep the first candidate that takes focus, else hold it on the panel.
    const focusFirst = () => {
      const candidates = [
        initialFocusRef.current?.current,
        ...panel.querySelectorAll<HTMLElement>(FOCUSABLE_SELECTOR),
      ];
      for (const candidate of candidates) {
        if (!candidate) continue;
        candidate.focus({ preventScroll: true });
        if (unmoved()) continue;
        // preventScroll keeps the page still, but it also stops the panel's
        // own scroll area from bringing a row below the fold into view.
        candidate.scrollIntoView?.({ block: "nearest" });
        return true;
      }
      panel.focus({ preventScroll: true });
      return false;
    };
    if (focusFirst()) return;
    const retry = (event: TransitionEvent) => {
      if (event.propertyName !== "visibility") return;
      if (!unmoved() || focusFirst()) stop();
    };
    const stop = () => {
      wrapper.removeEventListener("transitionend", retry);
      document.removeEventListener("keydown", stop, true);
      document.removeEventListener("pointerdown", stop, true);
    };
    wrapper.addEventListener("transitionend", retry);
    document.addEventListener("keydown", stop, true);
    document.addEventListener("pointerdown", stop, true);
    return stop;
  }, [ready, isPresent, contentRef, takeFocusOnOpen]);

  return (
    <motion.div
      data-morph-popover-portal=""
      inert={!isPresent}
      style={{
        left,
        top,
        opacity: reduce ? fade : surfaceOpacity,
        pointerEvents: isPresent ? "auto" : "none",
        visibility: layout ? "visible" : "hidden",
      }}
      // A drop-shadow follows the clipped surface; box-shadow would be cut
      // off by its own clip. Caller surface classes retain their old target.
      className={cn(
        "fixed z-[9999]",
        shadow && "[filter:drop-shadow(0_10px_18px_rgba(0,0,0,0.14))]",
      )}
    >
      <motion.div
        ref={ctx.contentRef}
        id={ctx.contentId}
        role="dialog"
        aria-labelledby={ctx.triggerId}
        tabIndex={-1}
        style={{
          clipPath: reduce ? undefined : clipPath,
          borderRadius: radius,
          maxHeight: layout ? availableHeight : undefined,
          overflowX: "hidden",
          overflowY: "auto",
        }}
        className={cn(
          // The panel holds focus when nothing inside it can. An inset ring
          // stays inside the clip that would cut off an outline.
          "border border-border bg-background outline-none focus-visible:ring-2 focus-visible:ring-inset focus-visible:ring-ring",
          className,
        )}
      >
        {children}
      </motion.div>
    </motion.div>
  );
}

"use client";

import {
  type MutableRefObject,
  useCallback,
  useLayoutEffect,
  useState,
} from "react";

export type PortalLayout = {
  trigger: {
    left: number;
    top: number;
    width: number;
    height: number;
  };
  content: {
    width: number;
    height: number;
  };
};

function sameLayout(a: PortalLayout | null, b: PortalLayout) {
  return (
    a?.trigger.left === b.trigger.left &&
    a.trigger.top === b.trigger.top &&
    a.trigger.width === b.trigger.width &&
    a.trigger.height === b.trigger.height &&
    a.content.width === b.content.width &&
    a.content.height === b.content.height
  );
}

/** Measures a trigger and portalled panel in viewport coordinates. */
export function usePopoverPortalPosition<
  TriggerElement extends HTMLElement,
  ContentElement extends HTMLElement,
>(
  triggerRef: MutableRefObject<TriggerElement | null>,
  contentRef: MutableRefObject<ContentElement | null>,
  active: boolean,
) {
  const [layout, setLayout] = useState<PortalLayout | null>(null);

  const update = useCallback(() => {
    const trigger = triggerRef.current;
    const content = contentRef.current;
    if (!trigger || !content) return;

    const rect = trigger.getBoundingClientRect();
    const next: PortalLayout = {
      trigger: {
        left: rect.left,
        top: rect.top,
        width: rect.width,
        height: rect.height,
      },
      content: {
        width: content.offsetWidth,
        height: content.offsetHeight,
      },
    };
    setLayout((current) => (sameLayout(current, next) ? current : next));
  }, [contentRef, triggerRef]);

  useLayoutEffect(() => {
    update();
    if (!active) return;

    const trigger = triggerRef.current;
    const content = contentRef.current;
    const observer = new ResizeObserver(update);
    if (trigger) observer.observe(trigger);
    if (content) observer.observe(content);

    window.addEventListener("scroll", update, true);
    window.addEventListener("resize", update);
    return () => {
      observer.disconnect();
      window.removeEventListener("scroll", update, true);
      window.removeEventListener("resize", update);
    };
  }, [active, contentRef, triggerRef, update]);

  return layout;
}