Chat App

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

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

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

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

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

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

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

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

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

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

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

"use client";

import { useEffect, useState } from "react";

/**
 * Returns true on devices that can be touched, whatever else they claim.
 *
 * This is not the inverse of `useHoverCapable`: iPadOS Safari browses
 * desktop-class and answers `(hover: hover) and (pointer: fine)` with true
 * while a finger is the only input there is, so anything that treats
 * hover-capable as "no touch here" strands every iPad. Gate the *touch path*
 * of an interaction on this hook and leave hover-only polish on
 * `useHoverCapable`, so a component that opens on hover also opens on tap.
 */
export function useTouchCapable() {
  const [canTouch, setCanTouch] = useState(false);

  useEffect(() => {
    if (typeof window === "undefined") return;
    const mq = window.matchMedia?.("(any-pointer: coarse)");
    // iPadOS disguises its pointer media queries; maxTouchPoints it reports
    // honestly, which is what makes it the standard iPad tell.
    const update = () =>
      setCanTouch(Boolean(mq?.matches) || navigator.maxTouchPoints > 0);
    update();
    mq?.addEventListener?.("change", update);
    return () => mq?.removeEventListener?.("change", update);
  }, []);

  return canTouch;
}

"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;
}

/**
 * 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(",");

import type { CSSProperties } from "react";

// The reduced-motion rule travels with the component. app/globals.css calms CSS
// animation globally, but the registry bundles imports only, so an installed
// copy never receives that reset.
//
// `!important` because the sweep is an inline style, which outranks a plain rule
// in a media query. It selects a marker class carried by TEXT_SHIMMER_CLASS_NAME
// so it also reaches consumers that build their own span out of these exports.
export const TEXT_SHIMMER_KEYFRAMES =
  "@keyframes beui-text-shimmer{from{background-position:200% 0}to{background-position:-200% 0}}" +
  "@media (prefers-reduced-motion: reduce){.beui-text-shimmer{animation:none !important}}";

export const TEXT_SHIMMER_CLASS_NAME =
  "beui-text-shimmer bg-[length:200%_100%] bg-clip-text text-transparent bg-[linear-gradient(110deg,var(--muted-foreground)_30%,var(--foreground)_50%,var(--muted-foreground)_70%)]";

export function textShimmerStyle(duration: number): CSSProperties {
  return {
    animation: `beui-text-shimmer ${duration}s linear infinite`,
  };
}

"use client";

import { type RefObject, useEffect } from "react";

/**
 * What the dismissing gesture does to the control it landed on.
 *
 * `"pass-through"` is the platform norm (native popover light-dismiss): the
 * tap closes the overlay *and* activates whatever was under it. Use
 * `"consume"` where the open overlay sits over or beside controls that would
 * be costly to trigger by accident — the dismissal then swallows the
 * activation too, so the gesture only closes.
 */
export type DismissBehavior = "pass-through" | "consume";

export interface DismissOptions {
  /** Default `"pass-through"`. */
  behavior?: DismissBehavior;
  /** Dismiss on Escape as well. Default true. */
  escape?: boolean;
  /** Return true for an outside target that should *not* dismiss. Must be stable. */
  ignore?: (target: Element) => boolean;
}

/**
 * What every currently open dismiss scope counts as inside itself. A consumed
 * dismissal reads this to tell a stray gesture from one that belongs to an
 * overlay in front of it: overlays have no shared z-order to consult, but the
 * one the gesture landed in has said as much by registering it.
 */
const openScopes = new Set<(target: Element) => boolean>();

function claimedByAnotherScope(
  self: (target: Element) => boolean,
  target: Element,
) {
  for (const scope of openScopes) {
    if (scope !== self && scope(target)) return true;
  }
  return false;
}

// preventDefault on pointerdown does not suppress the click that follows, so
// consuming a gesture means swallowing that click itself. The swallower
// deliberately outlives the effect that installed it — the dismissal it
// belongs to has already unmounted or re-rendered by the time the click lands.
// It releases on that click, or on the next gesture if the pointer is dragged
// away and no click ever arrives, so it can never eat a later one. A keydown
// releases it too: a gesture that ends with neither a click nor a cancel would
// otherwise leave it armed, and the click Enter synthesizes on some focused
// control is not the one this dismissal was owed.
function consumeActivation(source: Event) {
  const swallow = (event: MouseEvent) => {
    event.preventDefault();
    event.stopPropagation();
    release();
  };
  const restart = (event: Event) => {
    if (event !== source) release();
  };
  const release = () => {
    window.removeEventListener("click", swallow, true);
    window.removeEventListener("pointerdown", restart, true);
    window.removeEventListener("pointercancel", restart, true);
    window.removeEventListener("keydown", release, true);
  };
  window.addEventListener("click", swallow, true);
  window.addEventListener("pointerdown", restart, true);
  window.addEventListener("pointercancel", restart, true);
  window.addEventListener("keydown", release, true);
}

/**
 * Close an open overlay on Escape or a pointerdown outside `ref`. Pass `null`
 * for `ref` when what counts as inside isn't one element, and say so with
 * `ignore` instead.
 *
 * The pointerdown listener is capture-phase: a bubble-phase one is blinded by
 * any handler in between that stops propagation, and an overlay cannot know
 * what it is layered over. `onDismiss` and `ignore` must be stable (wrap in
 * useCallback) so the listeners aren't re-bound every render while open.
 */
export function useDismiss(
  open: boolean,
  onDismiss: () => void,
  ref: RefObject<HTMLElement | SVGElement | null> | null,
  {
    behavior = "pass-through",
    escape: dismissOnEscape = true,
    ignore,
  }: DismissOptions = {},
) {
  useEffect(() => {
    if (!open) return;
    const inside = (target: Element) =>
      Boolean(ref?.current?.contains(target)) || Boolean(ignore?.(target));
    const onKey = (event: KeyboardEvent) => {
      if (dismissOnEscape && event.key === "Escape") onDismiss();
    };
    const onPointer = (event: PointerEvent) => {
      const target = event.target as Element | null;
      if (!target || inside(target)) return;
      // Outside this overlay, but inside one that is also open: the gesture is
      // that overlay's to answer, and swallowing its click from behind would
      // cost the user the control they actually aimed at.
      if (behavior === "consume" && !claimedByAnotherScope(inside, target)) {
        consumeActivation(event);
      }
      onDismiss();
    };
    openScopes.add(inside);
    window.addEventListener("keydown", onKey);
    window.addEventListener("pointerdown", onPointer, true);
    return () => {
      openScopes.delete(inside);
      window.removeEventListener("keydown", onKey);
      window.removeEventListener("pointerdown", onPointer, true);
    };
  }, [open, onDismiss, ref, behavior, dismissOnEscape, ignore]);
}

"use client";

import { useMemo, useRef } from "react";
import { isHoveringPointer } from "@/lib/touch";

interface BoundaryEvent {
  pointerId: number;
  pointerType: string;
  buttons: number;
}

export interface HoverGesture {
  /** True when this enter starts a hover: the pointer arrived resting, not pressing. */
  enter: (event: BoundaryEvent) => boolean;
  /** True when this leave ends a hover that entered as one. */
  leave: (event: BoundaryEvent) => boolean;
}

/**
 * Pairs a surface's enter with its leave, per pointer.
 *
 * `isHoveringPointer` answers the question the *enter* asks — is this pointer
 * resting on the surface or pressing it — and both boundary cases go wrong if
 * the leave is asked the same question again:
 *
 * - A pen with no hover never rests. It arrives in contact, taps, and the spec
 *   then requires its boundary events after `pointerup`, so the leave carries
 *   `buttons: 0` and reads as a mouse gliding off. Hover teardown then undid
 *   the tap — the panel the pen had just opened closed under it.
 * - A mouse pressed on the surface and dragged off leaves with `buttons: 1`.
 *   Skipping teardown there strands the surface open: the release happens
 *   outside, and no second leave ever comes.
 *
 * So the state a hover holds is released by the pointer that took it, whatever
 * the buttons say at the boundary, and a pointer that arrived in contact never
 * took it in the first place. Contact is the exception tracked here, not
 * hover: a leave from a pointer this surface never saw enter — mounted under
 * the cursor, say — still counts, since the alternative is state with no way
 * out.
 */
export function useHoverGesture(): HoverGesture {
  const contact = useRef(new Set<number>());

  return useMemo(
    () => ({
      enter: (event) => {
        if (isHoveringPointer(event)) {
          contact.current.delete(event.pointerId);
          return true;
        }
        contact.current.add(event.pointerId);
        return false;
      },
      leave: (event) => {
        const arrivedInContact = contact.current.delete(event.pointerId);
        return !arrivedInContact && event.pointerType !== "touch";
      },
    }),
    [],
  );
}

"use client";

import { useMemo, useRef } from "react";

/** What a pointerdown recorded, read back by the click that ends its gesture. */
export interface TapRecord<S> {
  /** Which input started the gesture. */
  pointerType: string;
  /** What the surface was showing when it started. */
  state: S;
}

export interface TapGesture<S> {
  /** Record the gesture a pointerdown starts, with the state it starts in. */
  start: (event: { pointerType: string }, state: S) => void;
  /** Read the record and clear it. `null` when no pointer is behind this click. */
  take: () => TapRecord<S> | null;
  /** Drop the record: this gesture will never spend it on a click. */
  drop: () => void;
}

/**
 * The pointer gesture behind a click, recorded where the click cannot report
 * it. A `click` carries no `pointerType` in the engines that matter, so the
 * `pointerdown` before it is the only thing that says which input activated
 * the control — and whether one did at all, since keyboard activation
 * synthesizes a click with no pointer behind it.
 *
 * State goes in with the record because a click reports that no better: a
 * browser that focuses a control on contact can open the very panel the tap
 * was meant to open, and reading "is it open" at click time then undoes it.
 * What the gesture started against is what it acts on.
 *
 * The record is spent by one click and dropped by everything else, because a
 * record that outlives its gesture is worse than none:
 *
 * - A scroll or an OS gesture takes the touch away — `pointercancel`, no click
 *   ever — and the finger would sit in the record until some later click.
 * - That later click is often `Enter` on a keyboard, which arrives with no
 *   pointerdown of its own and would inherit the abandoned finger. A keydown
 *   is the start of a keyboard activation and never part of a tap, so it drops
 *   the record too.
 *
 * Both ends have to be wired by the surface: `drop` on `onPointerCancel` and
 * on `onKeyDown`.
 */
export function useTapGesture<S>(): TapGesture<S> {
  const record = useRef<TapRecord<S> | null>(null);

  return useMemo(
    () => ({
      start: (event, state) => {
        record.current = { pointerType: event.pointerType, state };
      },
      take: () => {
        const spent = record.current;
        record.current = null;
        return spent;
      },
      drop: () => {
        record.current = null;
      },
    }),
    [],
  );
}

"use client";

import {
  type KeyboardEvent,
  type RefObject,
  useEffect,
  useMemo,
  useRef,
} from "react";
import { useOnOpen } from "@/lib/hooks/use-on-open";
import { useRowCursor } from "@/lib/hooks/use-row-cursor";

export interface ListboxRow {
  id: string;
  label: string;
  disabled?: boolean;
}

// How long typed characters keep building one typeahead query.
const TYPEAHEAD_MS = 500;

/**
 * Keyboard model for a popup listbox whose options are focusable buttons.
 *
 * The active option is resolved during render through `useRowCursor`, so the
 * roving `tabIndex` and the next key press always agree with what is on
 * screen. Opening starts on the selected option, or the first enabled one.
 * Arrow keys, Home and End move between enabled options, and printable
 * characters jump to the next option whose label starts with what was typed.
 * DOM focus follows the active option while the list is open; each option
 * carries its id in `data-listbox-id` so the list can find it.
 */
export function useListbox({
  open,
  rows,
  selected,
  list,
}: {
  open: boolean;
  rows: readonly ListboxRow[];
  selected: string | undefined;
  list: RefObject<HTMLElement | null>;
}) {
  const enabled = useMemo(() => rows.filter((row) => !row.disabled), [rows]);
  const { activeIndex, moveTo, moveActive } = useRowCursor(enabled, "");
  useOnOpen(open, () =>
    moveTo(enabled.some((row) => row.id === selected) ? (selected ?? null) : null),
  );
  const activeId = enabled[activeIndex]?.id;
  const typed = useRef({ text: "", at: 0 });
  // A list rendered open does not take focus from the page on mount; focus
  // follows only once it has been opened, or once focus is already inside.
  const openedOnMount = useRef(open);
  useEffect(() => {
    if (!open) openedOnMount.current = false;
  }, [open]);

  useEffect(() => {
    if (!open || activeId === undefined) return;
    if (
      openedOnMount.current &&
      !list.current?.contains(document.activeElement)
    )
      return;
    const option = Array.from(
      list.current?.querySelectorAll<HTMLElement>("[data-listbox-id]") ?? [],
    ).find((element) => element.dataset.listboxId === activeId);
    option?.focus({ preventScroll: false });
  }, [open, activeId, list]);

  const onKeyDown = (event: KeyboardEvent) => {
    const { key } = event;
    if (key === "ArrowDown" || key === "ArrowUp") {
      event.preventDefault();
      moveActive(key === "ArrowDown" ? 1 : -1);
    } else if (key === "Home" || key === "End") {
      event.preventDefault();
      const row = key === "Home" ? enabled[0] : enabled[enabled.length - 1];
      if (row) moveTo(row.id);
    } else if (
      key.length === 1 &&
      key !== " " &&
      !event.ctrlKey &&
      !event.metaKey &&
      !event.altKey
    ) {
      const now = Date.now();
      const char = key.toLowerCase();
      const text =
        now - typed.current.at < TYPEAHEAD_MS ? typed.current.text + char : char;
      typed.current = { text, at: now };
      // A repeated single letter cycles through the options that start with it.
      const from = text.length === 1 ? activeIndex + 1 : activeIndex;
      for (let step = 0; step < enabled.length; step++) {
        const row = enabled[(from + step) % enabled.length];
        if (row.label.toLowerCase().startsWith(text)) {
          moveTo(row.id);
          break;
        }
      }
    }
  };

  return { activeId, onKeyDown };
}

"use client";

import { useCallback, useState } from "react";
import { getFaviconUrl } from "@/lib/favicon";

/**
 * Resolves a site favicon and drops it once it is known to be unusable, so
 * callers can draw their own glyph instead of a broken image. Plenty of sites
 * answer `/favicon.ico` with a 403 or 404, and `onError` is not enough to catch
 * it: an image the browser starts loading from server-rendered HTML usually
 * fails before React attaches a handler, and that event is never replayed.
 * `decode()` settles on the image's final state instead of relying on an event
 * firing at the right moment.
 */
export function useFavicon(url?: string) {
  const resolved = url ? getFaviconUrl(url) : null;
  const [failedSrc, setFailedSrc] = useState<string | null>(null);
  const src = resolved && resolved !== failedSrc ? resolved : null;

  const ref = useCallback(
    (img: HTMLImageElement | null) => {
      if (!img || !src) return;

      let released = false;
      img.decode().catch(() => {
        if (!released) setFailedSrc(src);
      });

      // The node is going away or the source changed; a late rejection then
      // describes an image we are no longer showing.
      return () => {
        released = true;
      };
    },
    [src],
  );

  return { src, ref };
}

// Shared touch primitives. iOS and iPadOS run their own gestures on top of the
// page — the long-press selection callout and the selection it drags in with
// it — and they win: once the platform claims a touch it cancels ours
// mid-gesture, so a press-and-hold or a drag simply dies. Surfaces that own
// their gesture have to opt out.
//
// What the two classes below cover, precisely:
// - `-webkit-touch-callout: none` stops iOS's long-press callout. WebKit-only:
//   it is not a property other engines have, so it is inert everywhere else.
// - `user-select: none` stops the long-press selection on every engine,
//   Android included, and stops a drag from painting a selection under the
//   cursor. It is inherited, so it reaches every descendant — which is why the
//   two classes differ only in whether they apply it unconditionally.
// What neither covers:
// - Chrome for Android's long-press menu on a link or an image. No CSS
//   suppresses it; a gesture surface that wraps one needs its own
//   `onContextMenu` with `preventDefault()`.
// - The native drag of an `<img>` or `<a>` descendant. `-webkit-user-drag` is
//   not inherited and plain divs and buttons are not drag sources, so setting
//   it on the surface does nothing — the child itself needs `draggable={false}`.

/**
 * Classes for a surface that *is* the control: a thumb, a drum, a stage, a
 * handle, a hold button. Selection is suppressed on every input, because a
 * drag that highlights the control's own label is wrong on a mouse too.
 * Compose with `touch-none` when the surface also owns the scroll axis — leave
 * it off when the page must still scroll from there.
 */
export const TOUCH_GESTURE_CLASS = "select-none [-webkit-touch-callout:none]";

/**
 * The same opt-out for a gesture surface that wraps content the consumer owns:
 * a scroller, a context-menu trigger, a sheet header, a list row. Selection is
 * suppressed only where the platform runs its own press gestures — a coarse
 * pointer — so a mouse user can still select and copy that content. If the
 * gesture itself would paint a selection under the cursor, add `select-none`
 * for the duration of the gesture rather than reaching for
 * `TOUCH_GESTURE_CLASS`.
 *
 * `pointer: coarse` describes the *primary* pointer and nothing else, so a
 * hybrid machine reads it wrong in both directions: a tablet with a mouse
 * plugged in keeps touch as primary and loses mouse selection, and a laptop
 * with a touchscreen keeps the mouse as primary and leaves selection live
 * under a finger. No media query can answer per interaction — the query is
 * about the device, and the question is about the gesture in progress. The
 * default stays here because it is right on the machines that are one thing or
 * the other, and losing a selection is a nuisance; where the miss costs a
 * *gesture* instead, the surface pairs it with `holdSelection` on the press.
 */
export const TOUCH_GESTURE_CONTENT_CLASS =
  "[-webkit-touch-callout:none] pointer-coarse:select-none";

/**
 * Suppress selection on `element` for as long as a gesture is running on it,
 * whatever the primary pointer of the machine happens to be. Returns the
 * release. Inline, so it wins over the class above and is gone again the
 * moment the gesture ends.
 *
 * For the press gestures a native selection would otherwise steal — a
 * long-press that opens a menu. Elsewhere prefer the classes: a surface that
 * takes selection away for the whole session is a surface whose text nobody
 * can copy.
 */
export function holdSelection(element: HTMLElement) {
  element.style.setProperty("user-select", "none");
  element.style.setProperty("-webkit-user-select", "none");
  return () => {
    element.style.removeProperty("user-select");
    element.style.removeProperty("-webkit-user-select");
  };
}

/**
 * Pointer capture, best effort. WebKit throws `NotFoundError` when the pointer
 * is already gone by the time the handler runs — routine on iOS, where the
 * system can claim the touch first — and an uncaught throw takes the rest of
 * the handler, the gesture included, down with it. Touch pointers carry
 * implicit capture anyway, so losing it is never fatal.
 */
export function capturePointer(element: Element, pointerId: number) {
  try {
    element.setPointerCapture(pointerId);
  } catch {
    // Pointer is no longer active — implicit capture still applies on touch.
  }
}

/** Release a capture taken with `capturePointer`, ignoring a stale pointer. */
export function releasePointer(element: Element, pointerId: number) {
  try {
    if (element.hasPointerCapture(pointerId)) {
      element.releasePointerCapture(pointerId);
    }
  } catch {
    // Capture was already dropped by the browser.
  }
}

/**
 * Whether this event came from a pointer that is *hovering*: not a touch, and
 * not currently pressed. Which input the user is holding right now is not
 * something a device capability can answer — a touchscreen laptop hovers and
 * taps, and iPadOS reports a fine hovering pointer for a finger — so both
 * paths stay live and each handler branches on the event it was given.
 *
 * A pen resting on the glass is making contact, not hovering: `buttons` is the
 * tell, and it sends a pen tap down the same route a finger takes.
 *
 * This answers what an *enter* asks. A leave is the other half of a pair and
 * has to be read against the enter that started it — `useHoverGesture` in
 * `lib/hooks/use-hover-gesture` does that, and hover surfaces should use it
 * rather than asking this question twice.
 */
export const isHoveringPointer = (event: {
  pointerType: string;
  buttons: number;
}) => event.pointerType !== "touch" && event.buttons === 0;

"use client";

import { useState } from "react";

/**
 * Runs `start` during the render in which `open` becomes true.
 *
 * Opening a list starts a fresh session — an empty query, the highlight back at
 * the top — and that is a resolution, not a side effect: a passive effect runs
 * after the commit, so the new session would carry the last one's state for a
 * window in which a key press can land.
 *
 * `start` may only set state belonging to the calling component. Anything that
 * reaches outside it — a consumer's callback, a DOM write, moving focus — is a
 * side effect, and React rejects a callback that sets another component's state
 * during this one's render. Put those in an effect keyed to `open`.
 */
export function useOnOpen(open: boolean, start: () => void) {
  const [wasOpen, setWasOpen] = useState(open);
  if (open !== wasOpen) {
    setWasOpen(open);
    if (open) start();
  }
}

"use client";

import { useCallback, useLayoutEffect, useRef, useState } from "react";

/**
 * Where the keyboard or the pointer last moved to: the row's id, stamped with
 * the query it was placed under.
 */
type RowCursor = { id: string; query: string };

/** The cursor's row, or -1 once the query has moved on or the row has left. */
function indexOfCursor(
  rows: readonly { id: string }[],
  query: string,
  cursor: RowCursor | null,
) {
  if (cursor === null || cursor.query !== query) return -1;
  return rows.findIndex((row) => row.id === cursor.id);
}

/**
 * The highlighted row of a list whose rows can change under it.
 *
 * Which row is highlighted is resolved during render, never in a passive
 * effect: a passive effect runs after the commit, so a list that had just
 * changed would carry an `aria-activedescendant` naming a row that has left it,
 * and a key pressed in that window would commit the wrong row or nothing at
 * all.
 *
 * The cursor holds the row's id, not its position. A position alone cannot tell
 * a list that shrank from one that swapped its rows for a different set of the
 * same length, and the second case is the one that silently hands Enter to a
 * row the user never chose. A cursor whose row has left the list returns the
 * highlight to the first row rather than to the nearest surviving one: the row
 * the user aimed at is gone, and the first row is where a new query already
 * puts the highlight.
 *
 * Pass the query the list is filtered by. The cursor is stamped with it and
 * dropped when it changes, so a caller cannot forget to clear it — including a
 * caller whose query arrives as a prop and so never runs its own handler. Rows
 * that come back under a query that has moved on cannot revive it either.
 * `moveTo(null)` is for deliberate resets, such as reopening the list.
 *
 * Both callbacks keep one identity for the life of the component, and read the
 * rows and the query through a ref to do it. A caller will put them in an
 * effect's dependencies — the exhaustive-deps rule makes it — and a `moveTo`
 * rebuilt on every keystroke would re-run that effect on every keystroke.
 */
export function useRowCursor(rows: readonly { id: string }[], query: string) {
  const [cursor, setCursor] = useState<RowCursor | null>(null);
  // Written after commit, not during render: a render React discards or has not
  // finished still runs the component body, and an event handler that read this
  // in that window would stamp the cursor with a query the committed tree does
  // not have.
  const latest = useRef({ rows, query });
  useLayoutEffect(() => {
    latest.current = { rows, query };
  });

  const cursorRow = indexOfCursor(rows, query, cursor);
  // Cleared rather than ignored: React re-runs this render with the cursor
  // already gone, so rows that come back cannot revive a highlight the user has
  // stopped aiming at.
  if (cursor !== null && cursorRow < 0) setCursor(null);

  const moveTo = useCallback(
    (id: string | null) =>
      setCursor(id === null ? null : { id, query: latest.current.query }),
    [],
  );

  const moveActive = useCallback((direction: 1 | -1) => {
    const { rows: live, query: liveQuery } = latest.current;
    const last = live.length - 1;
    if (last < 0) return;
    // Steps from the row the cursor is really on, inside the update, so that
    // two keys landing in one batch move two rows rather than one.
    setCursor((current) => {
      const at = Math.max(indexOfCursor(live, liveQuery, current), 0);
      const next = Math.min(Math.max(at + direction, 0), last);
      return { id: live[next].id, query: liveQuery };
    });
  }, []);

  return { activeIndex: cursorRow < 0 ? 0 : cursorRow, moveTo, moveActive };
}

/** Resolve a website URL to its conventional root favicon location. */
export function getFaviconUrl(value: string) {
  try {
    return new URL("/favicon.ico", value).toString();
  } catch {
    return null;
  }
}

"use client";
// beui.dev/components/agents/chat-app

import { useEffect, useRef } from "react";
import {
  AnimatedSidebarProvider,
  type AnimatedSidebarProviderProps,
  useAnimatedSidebar,
} from "@/components/motion/animated-sidebar";
import { cn } from "@/lib/utils";

/**
 * Shell width below which a docked sidebar leaves too little room for the
 * conversation: the default sidebar is 17rem, so under 600px the conversation
 * pane is left with barely 330px — narrower than a phone.
 *
 * Deliberately not AnimatedSidebar's own 767px mobile query: that one asks
 * whether the *viewport* is a phone (and swaps the sidebar for an off-canvas
 * sheet), this one asks whether the *shell's own box* — which may be a column,
 * a split view or a panel inside a much wider page — still fits both panes.
 */
const MIN_DOCKED_WIDTH = 600;

export interface ChatAppProps extends AnimatedSidebarProviderProps {
  /** Docked sidebar width as a CSS length. Default `17rem`. */
  sidebarWidth?: string;
  /**
   * Shell width in px under which the sidebar folds off-canvas. Ignored while
   * `open` is controlled — the consumer owns the state then.
   */
  collapseSidebarBelow?: number;
}

/**
 * Folds the sidebar away while the shell is too narrow to carry both panes,
 * and brings it back when it isn't. Only crossings are acted on, so a manual
 * toggle at either size stays put until the shell actually changes shape.
 *
 * Mount is not a crossing in the opening direction: a shell that merely has
 * room says nothing about whether the caller wanted the sidebar open, so the
 * first measurement leaves `defaultOpen` alone. Too narrow at mount *is* the
 * fold condition itself, so that half applies immediately.
 */
function ShellFit({ minWidth }: { minWidth: number }) {
  const { open, setOpen } = useAnimatedSidebar();
  const markerRef = useRef<HTMLDivElement>(null);
  const narrowRef = useRef<boolean | null>(null);
  const openRef = useRef(open);
  openRef.current = open;

  useEffect(() => {
    const shell = markerRef.current?.parentElement;
    if (!shell) return;
    const observer = new ResizeObserver(([entry]) => {
      const narrow = entry.contentRect.width < minWidth;
      if (narrowRef.current === narrow) return;
      const first = narrowRef.current === null;
      narrowRef.current = narrow;
      if (first && !narrow) return;
      const wanted = !narrow;
      // Already where the shell wants it — saying so again would only be an
      // onOpenChange the caller never asked for.
      if (openRef.current === wanted) return;
      setOpen(wanted);
    });
    observer.observe(shell);
    return () => observer.disconnect();
  }, [minWidth, setOpen]);

  return <div ref={markerRef} className="hidden" />;
}

export function ChatApp({
  children,
  className,
  sidebarWidth = "17rem",
  collapseSidebarBelow = MIN_DOCKED_WIDTH,
  style,
  ...props
}: ChatAppProps) {
  return (
    <AnimatedSidebarProvider
      {...props}
      style={{ ...style, "--sidebar-width": sidebarWidth }}
      className={cn(
        "min-h-0 w-full overflow-hidden rounded-2xl border border-border bg-background",
        className,
      )}
    >
      {/* A controlled `open` is the consumer's to change; fitting the shell
          would fire an onOpenChange they never asked for. */}
      {props.open === undefined ? (
        <ShellFit minWidth={collapseSidebarBelow} />
      ) : null}
      {children}
    </AnimatedSidebarProvider>
  );
}

"use client";
// beui.dev/components/agents/chat-app

import { ChevronDown } from "lucide-react";
import { AnimatePresence, motion, useReducedMotion } from "motion/react";
import {
  type ReactNode,
  useCallback,
  useEffect,
  useId,
  useLayoutEffect,
  useRef,
  useState,
} from "react";
import { ThinkingShimmer } from "@/components/agents/loading-states/thinking-shimmer";
import { AgentDisclosure } from "@/components/agents/agent-disclosure";
import {
  EASE_OUT,
  SPRING_LAYOUT,
  SPRING_SWAP,
} from "@/lib/ease";
import { cn } from "@/lib/utils";
import { ActivityRow } from "./activity-row";
import type {
  AgentActivityContentType,
  AgentActivityItem,
  AgentActivityProps,
} from "./types";

export type {
  AgentActivityContentType,
  AgentActivityItem,
  AgentActivityProps,
  AgentActivitySearch,
  AgentActivityStatus,
  AgentActivityStep,
  AgentActivityText,
  AgentActivityTool,
  AgentActivityTrace,
  AgentSearchResult,
  AgentStepStatus,
  AgentTraceKind,
} from "./types";

function formatDuration(duration: number) {
  const seconds = Math.max(0, Math.round(duration));
  if (seconds < 60) return `${seconds}s`;

  const minutes = Math.floor(seconds / 60);
  const remainder = seconds % 60;
  return remainder === 0 ? `${minutes}m` : `${minutes}m ${remainder}s`;
}

function useControllableOpen({
  open,
  defaultOpen,
  onOpenChange,
}: {
  open?: boolean;
  defaultOpen: boolean;
  onOpenChange?: (open: boolean) => void;
}) {
  const [internalOpen, setInternalOpen] = useState(defaultOpen);
  const controlled = open !== undefined;
  const currentOpen = open ?? internalOpen;

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

  return [currentOpen, setOpen] as const;
}

function getContentType(items: AgentActivityItem[]): AgentActivityContentType {
  const first = items[0]?.type;
  return first && items.every((item) => item.type === first) ? first : "mixed";
}

function getActiveLabel(type: AgentActivityContentType) {
  if (type === "search") return "Searching the web…";
  if (type === "tool") return "Running tools…";
  if (type === "trace") return "Working through the run…";
  if (type === "mixed") return "Working through it…";
  return "Thinking…";
}

function getSummary(
  type: AgentActivityContentType,
  items: AgentActivityItem[],
  duration: number,
): ReactNode {
  if (type === "step" || type === "text") {
    return (
      <>
        Thought for <span className="tabular-nums">{formatDuration(duration)}</span>
      </>
    );
  }
  if (type === "search") return "Searched the web";
  if (type === "tool") {
    return `Ran ${items.length} ${items.length === 1 ? "tool" : "tools"}`;
  }
  if (type === "trace") {
    const messages = items.filter(
      (item) =>
        item.type === "trace" &&
        (item.kind === "thinking" || item.kind === "message"),
    ).length;
    const tools = items.length - messages;
    return `${tools} ${tools === 1 ? "tool call" : "tool calls"}, ${messages} ${messages === 1 ? "message" : "messages"}`;
  }
  return `Completed ${items.length} ${items.length === 1 ? "step" : "steps"}`;
}

export function AgentActivity({
  items,
  contentType: initialContentType,
  status = "working",
  duration = 0,
  open,
  defaultOpen = false,
  onOpenChange,
  collapseOnComplete = true,
  activeLabel,
  summary,
  renderWorkingStatus,
  renderCompletedStatus,
  maxHeight = 208,
  className,
  contentClassName,
}: AgentActivityProps) {
  const reduce = useReducedMotion() ?? false;
  const baseId = useId();
  const triggerId = `${baseId}-trigger`;
  const contentId = `${baseId}-content`;
  const contentRef = useRef<HTMLDivElement>(null);
  const viewportRef = useRef<HTMLDivElement>(null);
  const previousStatus = useRef(status);
  const [contentHeight, setContentHeight] = useState(0);
  const [currentOpen, setOpen] = useControllableOpen({
    open,
    defaultOpen,
    onOpenChange,
  });
  const working = status === "working";
  const expanded = working || currentOpen;
  const contentType = items.length
    ? getContentType(items)
    : (initialContentType ?? "mixed");
  const cappedHeight = Math.min(contentHeight, Math.max(0, maxHeight));
  const viewportHeight = working ? Math.max(0, maxHeight) : cappedHeight;
  const capped = contentHeight > maxHeight;
  const streamOffset = working
    ? Math.min(0, viewportHeight - contentHeight)
    : 0;

  useLayoutEffect(() => {
    const node = contentRef.current;
    if (!node) return;

    const measure = () => setContentHeight(node.offsetHeight);
    measure();

    if (typeof ResizeObserver === "undefined") return;
    const observer = new ResizeObserver(measure);
    observer.observe(node);
    return () => observer.disconnect();
  }, []);

  useEffect(() => {
    if (previousStatus.current === "working" && status === "complete") {
      setOpen(!collapseOnComplete);
    }
    previousStatus.current = status;
  }, [collapseOnComplete, setOpen, status]);

  const toggle = () => {
    const next = !currentOpen;
    setOpen(next);
    if (next) requestAnimationFrame(() => viewportRef.current?.scrollTo({ top: 0 }));
  };

  const liveLabel = activeLabel ?? getActiveLabel(contentType);
  const completedSummary = summary ?? getSummary(contentType, items, duration);
  const maskImage = capped
    ? working
      ? "linear-gradient(to bottom, transparent, black 12px)"
      : "linear-gradient(to bottom, transparent, black 12px, black calc(100% - 12px), transparent)"
    : undefined;

  return (
    <div
      data-state={working ? "working" : expanded ? "open" : "closed"}
      data-content={contentType}
      aria-busy={working}
      className={cn("w-full text-sm", className)}
    >
      {working ? (
        <div
          id={triggerId}
          role="status"
          className="flex h-7 min-w-0 items-center text-muted-foreground"
        >
          {renderWorkingStatus
            ? renderWorkingStatus({ label: liveLabel, duration })
            : <ThinkingShimmer>{liveLabel}</ThinkingShimmer>}
        </div>
      ) : (
        <button
          id={triggerId}
          type="button"
          aria-expanded={expanded}
          aria-controls={contentId}
          onClick={toggle}
          className="group flex h-7 min-w-0 items-center gap-1.5 rounded-md text-left font-medium text-muted-foreground outline-none transition-colors hover:text-foreground focus-visible:ring-2 focus-visible:ring-ring focus-visible:ring-offset-2 focus-visible:ring-offset-background"
        >
          <span className="truncate">
            {renderCompletedStatus
              ? renderCompletedStatus({ summary: completedSummary, duration })
              : completedSummary}
          </span>
          <motion.span
            aria-hidden="true"
            animate={{ rotate: expanded ? 180 : 0 }}
            transition={reduce ? { duration: 0 } : SPRING_SWAP}
            className="inline-flex shrink-0 text-muted-foreground/70 group-hover:text-foreground"
          >
            <ChevronDown className="size-3.5" />
          </motion.span>
        </button>
      )}

      <AgentDisclosure
        id={contentId}
        role="region"
        aria-labelledby={triggerId}
        open={expanded}
        openHeight={viewportHeight}
      >
        <div
          ref={viewportRef}
          className={cn(
            "scrollbar-hide pr-1",
            capped && expanded && !working ? "overflow-y-auto" : "overflow-y-hidden",
          )}
          style={{ height: viewportHeight, maskImage, WebkitMaskImage: maskImage }}
        >
          <motion.div
            ref={contentRef}
            role="list"
            initial={false}
            animate={{ y: streamOffset }}
            transition={reduce ? { duration: 0 } : SPRING_LAYOUT}
            className={cn("space-y-0.5 py-2", contentClassName)}
          >
            <AnimatePresence mode="popLayout">
              {items.map((item) => (
                <motion.div
                  layout="position"
                  key={item.id}
                  role="listitem"
                  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,
                        }
                  }
                >
                  <ActivityRow item={item} />
                </motion.div>
              ))}
            </AnimatePresence>
          </motion.div>
        </div>
      </AgentDisclosure>
    </div>
  );
}