Drawer

// 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 { type RefObject, useEffect, useLayoutEffect, useRef } from "react";

const FOCUSABLE =
  'button:not(:disabled), a[href], input:not(:disabled), select:not(:disabled), textarea:not(:disabled), [tabindex]:not([tabindex="-1"])';

/** Elements inside `container` that Tab can reach, in DOM order. */
export function focusablesIn(container: Element | null) {
  return Array.from(
    container?.querySelectorAll<HTMLElement>(FOCUSABLE) ?? [],
  ).filter((element) => element.tabIndex >= 0 && !element.closest("[inert]"));
}

/**
 * Open traps, innermost last. Only the innermost one answers Tab, Escape and
 * stray focus: a sheet opened from inside a drawer portals outside the drawer,
 * and a drawer that still pulled focus home would fight the sheet for it.
 */
const traps: object[] = [];

export interface FocusTrapOptions {
  /** Called on Escape while this is the innermost open trap. */
  onEscape?: () => void;
}

/**
 * Moves focus into `panel` when `open` turns true, keeps Tab cycling inside it,
 * pulls focus back if it lands outside, and returns focus to whatever held it
 * before opening once `open` turns false.
 *
 * For overlays rendered in place, where `useModalScope` cannot inert the rest
 * of the page. Pass `open` rather than presence: an exiting panel is already
 * inert through `PresenceGate`, so the trap releases with the same commit.
 * Give the panel `tabIndex={-1}` so it can take focus when it holds nothing
 * focusable.
 */
export function useFocusTrap(
  open: boolean,
  panel: RefObject<HTMLElement | null>,
  { onEscape }: FocusTrapOptions = {},
) {
  const escapeRef = useRef(onEscape);
  useLayoutEffect(() => {
    escapeRef.current = onEscape;
  });

  useEffect(() => {
    if (!open || !panel.current) return;
    const self = {};
    traps.push(self);
    const innermost = () => traps[traps.length - 1] === self;
    const returnFocus =
      document.activeElement instanceof HTMLElement
        ? document.activeElement
        : null;
    const focusables = () => focusablesIn(panel.current);    const focusFirst = () =>
      (focusables()[0] ?? panel.current)?.focus({ preventScroll: true });
    if (!panel.current.contains(document.activeElement)) focusFirst();

    const onFocus = (event: FocusEvent) => {
      if (!innermost() || !panel.current || panel.current.closest("[inert]"))
        return;
      if (event.target instanceof Node && !panel.current.contains(event.target))
        focusFirst();
    };
    const onKey = (event: KeyboardEvent) => {
      if (!innermost() || event.defaultPrevented) return;
      if (event.key === "Escape" && escapeRef.current) {
        event.preventDefault();
        escapeRef.current();
        return;
      }
      if (event.key !== "Tab") return;
      const elements = focusables();
      const first = elements[0];
      const last = elements[elements.length - 1];
      const active = document.activeElement;
      if (!first || !last) {
        event.preventDefault();
        panel.current?.focus({ preventScroll: true });
      } else if (event.shiftKey && (active === first || active === panel.current)) {
        event.preventDefault();
        last.focus();
      } else if (!event.shiftKey && active === last) {
        event.preventDefault();
        first.focus();
      }
    };
    document.addEventListener("focusin", onFocus);
    document.addEventListener("keydown", onKey);
    return () => {
      document.removeEventListener("focusin", onFocus);
      document.removeEventListener("keydown", onKey);
      traps.splice(traps.indexOf(self), 1);
      if (returnFocus?.isConnected && !returnFocus.closest("[inert]"))
        returnFocus.focus({ preventScroll: true });
    };
  }, [open, panel]);
}

"use client";

import { useIsPresent } from "motion/react";
import type { ReactNode } from "react";

export interface PresenceGateRenderProps {
  /**
   * False from the render that starts the exit animation onward. An overlay
   * kept in the tree by `AnimatePresence` is still the topmost thing on the
   * page, so anything it decides from `open` alone stays true for the whole
   * exit — this is the boolean that already knows the overlay is leaving.
   */
  isPresent: boolean;
  /**
   * Spread onto every layer that takes pointer events while the overlay is
   * open. Interaction releases in the same commit that starts the exit while
   * the visual exit keeps playing: pointer events stop landing, and `inert`
   * drops the subtree from focus order, from tab order and from the
   * accessibility tree — an exiting dialog is not a dialog you can still type
   * into. A layer that never takes pointer events (a wrapper that only centres
   * the panel) takes `inert={!isPresent}` alone, so its own
   * `pointer-events-none` is not overwritten.
   */
  gate: {
    inert: boolean;
    style: { pointerEvents: "auto" | "none" };
  };
}

export interface PresenceGateProps {
  children: (props: PresenceGateRenderProps) => ReactNode;
}

/**
 * Reads the presence of the subtree it renders and hands it down.
 *
 * `useIsPresent` only answers inside the `AnimatePresence` subtree, and the
 * components that own an overlay render the `AnimatePresence` themselves, so
 * the boolean has to be read one component further down: this is that
 * component, and the render prop is how it reaches the layers.
 */
export function PresenceGate({ children }: PresenceGateProps) {
  const isPresent = useIsPresent();

  return children({
    isPresent,
    gate: {
      inert: !isPresent,
      style: { pointerEvents: isPresent ? "auto" : "none" },
    },
  });
}

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/motion/drawer

import { AnimatePresence, motion, useReducedMotion } from "motion/react";
import { useEffect, useRef, type ReactNode } from "react";
import { EASE_OUT, SPRING_PANEL } from "@/lib/ease";
import { useFocusTrap } from "@/lib/hooks/use-focus-trap";
import { PresenceGate } from "@/lib/presence-gate";
import { cn } from "@/lib/utils";

export interface DrawerProps {
  open: boolean;
  onOpenChange: (open: boolean) => void;
  side?: "left" | "right";
  children: ReactNode;
  /** Class for the panel surface. */
  className?: string;
  /** Class for the backdrop. */
  backdropClassName?: string;
  ariaLabel?: string;
  /** Close when the backdrop is clicked or Escape is pressed. Default true. */
  dismissable?: boolean;
}

export function Drawer({
  open,
  onOpenChange,
  side = "right",
  children,
  className,
  backdropClassName,
  ariaLabel,
  dismissable = true,
}: DrawerProps) {
  const reduce = useReducedMotion();
  const panelRef = useRef<HTMLDivElement>(null);

  // Focus moves into the panel on open, Tab stays inside it, and focus returns
  // to the opener on close.
  useFocusTrap(open, panelRef, {
    onEscape: dismissable ? () => onOpenChange(false) : undefined,
  });

  useEffect(() => {
    if (!open) return;
    const prevOverflow = document.body.style.overflow;
    document.body.style.overflow = "hidden";
    return () => {
      document.body.style.overflow = prevOverflow;
    };
  }, [open]);

  const offscreen = side === "right" ? "100%" : "-100%";

  // Two fixed siblings, no wrapper: the backdrop spans the viewport edges but
  // paints the scrim, and the panel is inset off one side and paints its own
  // surface, so neither is a transparent edge-spanning layer. Both hang off
  // `PresenceGate`, so interaction releases in the same commit that starts the
  // exit rather than when it ends.
  return (
    <AnimatePresence>
      {open ? (
        <PresenceGate key="backdrop">
          {({ gate }) => (
            <motion.button
              type="button"
              aria-label="Close"
              // Outside the panel, so the focus trap never lands on it; it is
              // a pointer target only.
              tabIndex={-1}
              onClick={() => dismissable && onOpenChange(false)}
              initial={{ opacity: 0 }}
              animate={{ opacity: 1 }}
              exit={{ opacity: 0 }}
              transition={{ duration: 0.25, ease: EASE_OUT }}
              {...gate}
              className={cn(
                "fixed inset-0 z-50 h-full w-full cursor-default bg-black/40 backdrop-blur-sm",
                backdropClassName,
              )}
            />
          )}
        </PresenceGate>
      ) : null}
      {open ? (
        <PresenceGate key="panel">
          {({ gate }) => (
            <motion.div
              ref={panelRef}
              tabIndex={-1}
              role="dialog"
              aria-modal="true"
              aria-label={ariaLabel}
              initial={reduce ? { opacity: 0 } : { x: offscreen }}
              animate={reduce ? { opacity: 1 } : { x: 0 }}
              exit={reduce ? { opacity: 0 } : { x: offscreen }}
              transition={
                reduce ? { duration: 0.2, ease: EASE_OUT } : SPRING_PANEL
              }
              {...gate}
              className={cn(
                "fixed inset-y-0 z-50 flex w-80 max-w-[85vw] flex-col bg-background shadow-2xl outline-none",
                side === "right"
                  ? "right-0 border-l border-border"
                  : "left-0 border-r border-border",
                className,
              )}
            >
              {children}
            </motion.div>
          )}
        </PresenceGate>
      ) : null}
    </AnimatePresence>
  );
}