React context menu

'use client';

import { useCallback, useEffect, useId, useLayoutEffect, useRef, useState } from 'react';
import { createPortal } from 'react-dom';
import { cn, useTexts } from '@/lib/kit';
import { Icon, type IconName } from '@/components/ui/icon';

/*
 * Name note: dropdown-menu.tsx also exports a small ContextMenu (right click only, flat MenuItem list).
 * The CLI installs each component into its own file and neither imports the other, so both live
 * side by side in one project. To use both in one file, rename on import:
 *   import { ContextMenu as RichContextMenu } from '@/components/ui/context-menu';
 * This one adds long press, Shift F10, submenus and checkbox and radio items.
 */
const useIsoLayoutEffect = typeof window === 'undefined' ? useEffect : useLayoutEffect;

const TEXTS = {
  en: { menu: 'Actions', hint: 'Right click, long press, or press Shift F10 for actions.', back: 'Back' },
  de: { menu: 'Aktionen', hint: 'Rechtsklick, lange drücken oder Umschalt F10 für Aktionen.', back: 'Zurück' },
};

export type ContextMenuItem =
  | {
      type?: 'item';
      /** Passed to onAction */
      id?: string;
      label: string;
      icon?: IconName;
      /** Shown on the right and set as aria-keyshortcuts, e.g. ⌘C */
      shortcut?: string;
      description?: string;
      disabled?: boolean;
      destructive?: boolean;
      /** A destructive action asks once more in place: the label turns into this text, a second press confirms */
      confirm?: string;
    }
  | { type: 'checkbox'; id: string; label: string; checked?: boolean; icon?: IconName; shortcut?: string; disabled?: boolean }
  | { type: 'radio'; group: string; value: string; label: string; checked?: boolean; disabled?: boolean }
  | { type: 'submenu'; label: string; icon?: IconName; items: ContextMenuItem[]; disabled?: boolean }
  | { type: 'label'; label: string }
  | { type: 'separator' };

export interface ContextMenuProps {
  items: ContextMenuItem[];
  /**
   * Called with the id of a chosen item (checkbox: id and the new state, radio: group and value) and the
   * `data-context` value of the element that was right clicked, so one menu serves a whole list.
   */
  onAction?: (id: string, context: string | null, detail?: boolean | string) => void;
  /** A heading inside the menu, e.g. the name of the file. A function gets the data-context value. */
  title?: string | ((context: string | null) => string | undefined);
  /** Show a small line under the area that tells how to open the menu */
  showHint?: boolean;
  /** Open right away, at this point inside the area (px from its top left), for previews */
  defaultOpen?: boolean;
  defaultPosition?: { x: number; y: number };
  /** Open after a long press on touch screens, on by default */
  longPress?: boolean;
  labels?: Partial<(typeof TEXTS)['en']>;
  className?: string;
  /** The area. Elements inside with data-context="…" tell onAction what was clicked. */
  children: React.ReactNode;
}

type Point = { x: number; y: number };
const MARGIN = 8;

/* Items arrive one after another from the pointer */
const CSS =
  '.kitfx-cm{transform-origin:var(--origin,top left);animation:kitfx-cm-in .2s cubic-bezier(.34,1.3,.64,1) both}' +
  '.kitfx-cm-item{animation:kitfx-cm-item .28s var(--ease-kit) both;animation-delay:calc(var(--i,0) * 18ms + 20ms)}' +
  '@keyframes kitfx-cm-in{from{opacity:0;transform:scale(.94)}}@keyframes kitfx-cm-item{from{opacity:0;transform:translateY(-3px)}}' +
  '@media (prefers-reduced-motion:reduce){.kitfx-cm,.kitfx-cm-item{animation:none}}';

function initialState(items: ContextMenuItem[], checks: Record<string, boolean> = {}, radios: Record<string, string> = {}) {
  for (const it of items) {
    if (it.type === 'checkbox') checks[it.id] = Boolean(it.checked);
    if (it.type === 'radio' && it.checked) radios[it.group] = it.value;
    if (it.type === 'submenu') initialState(it.items, checks, radios);
  }
  return { checks, radios };
}

const isAction = (it: ContextMenuItem) => it.type !== 'label' && it.type !== 'separator';

/**
 * A context menu after the APG menu pattern, opened by right click, long press, the context menu key or
 * Shift F10. Arrows, Home, End and typeahead, submenus with Right and Left, checkbox and radio items,
 * shortcuts, a destructive action that asks once more, kept inside the window, focus back on close.
 *   <ContextMenu items={[{ id: 'copy', label: 'Copy', shortcut: '⌘C' }, …]} onAction={(id, ctx) => …}><FileList /></ContextMenu>
 */
export function ContextMenu({ items, onAction, title, showHint, defaultOpen, defaultPosition, longPress = true, labels, className, children }: ContextMenuProps) {
  const t = useTexts(TEXTS, labels);
  const id = useId();
  const areaRef = useRef<HTMLDivElement>(null);
  // Where it opened, relative to the area, so the menu stays put while the page scrolls
  const [at, setAt] = useState<(Point & { context: string | null; keyboard: boolean; preview?: boolean }) | null>(null);
  const [mounted, setMounted] = useState(false);
  const returnTo = useRef<HTMLElement | null>(null);
  const [state, setState] = useState(() => initialState(items));

  useEffect(() => {
    setMounted(true);
    if (!defaultOpen || !areaRef.current) return;
    const pos = defaultPosition ?? { x: 24, y: 24 };
    const r = areaRef.current.getBoundingClientRect();
    const under = document.elementFromPoint(r.left + pos.x, r.top + pos.y)?.closest('[data-context]') ?? areaRef.current.querySelector('[data-context]');
    setAt({ ...pos, context: under?.getAttribute('data-context') ?? null, keyboard: false, preview: true });
  }, [defaultOpen, defaultPosition?.x, defaultPosition?.y]);

  const openAt = (clientX: number, clientY: number, target: EventTarget | null, keyboard: boolean) => {
    const area = areaRef.current;
    if (!area) return;
    const r = area.getBoundingClientRect();
    const ctxEl = (target as HTMLElement | null)?.closest?.('[data-context]');
    returnTo.current = (document.activeElement as HTMLElement) ?? area;
    setAt({ x: clientX - r.left, y: clientY - r.top, context: ctxEl?.getAttribute('data-context') ?? null, keyboard });
  };

  const close = useCallback((focusBack: boolean) => {
    setAt(null);
    if (focusBack) (returnTo.current && document.contains(returnTo.current) ? returnTo.current : areaRef.current)?.focus({ preventScroll: true });
  }, []);

  /* ---------- long press on touch ---------- */
  const press = useRef<{ timer: number; x: number; y: number } | null>(null);
  const cancelPress = () => {
    if (press.current) window.clearTimeout(press.current.timer);
    press.current = null;
  };

  const choose = (it: ContextMenuItem, context: string | null) => {
    if (it.type === 'checkbox') {
      const next = !state.checks[it.id];
      setState((s) => ({ ...s, checks: { ...s.checks, [it.id]: next } }));
      onAction?.(it.id, context, next);
      return false;
    }
    if (it.type === 'radio') {
      setState((s) => ({ ...s, radios: { ...s.radios, [it.group]: it.value } }));
      onAction?.(it.group, context, it.value);
      return true;
    }
    if (it.type === undefined || it.type === 'item') onAction?.(it.id ?? it.label, context);
    return true;
  };

  const heading = at ? (typeof title === 'function' ? title(at.context) : title) : undefined;

  return (
    <>
    <div
      ref={areaRef}
      tabIndex={0}
      aria-describedby={`${id}-hint`}
      aria-haspopup="menu"
      onContextMenu={(e) => {
        e.preventDefault();
        cancelPress();
        if ((e.target as HTMLElement).closest?.('[data-cm-panel]')) return;
        // A context menu key press reports 0,0: open at the focused element instead
        if (e.clientX === 0 && e.clientY === 0) {
          const el = (document.activeElement as HTMLElement) ?? e.currentTarget;
          const r = el.getBoundingClientRect();
          openAt(r.left + Math.min(24, r.width / 2), r.top + Math.min(r.height, 32), el, true);
        } else openAt(e.clientX, e.clientY, e.target, false);
      }}
      onKeyDown={(e) => {
        if (((e.key === 'F10' && e.shiftKey) || e.key === 'ContextMenu') && !(e.target as HTMLElement).closest?.('[data-cm-panel]')) {
          e.preventDefault();
          const el = e.target as HTMLElement;
          const r = el.getBoundingClientRect();
          openAt(r.left + Math.min(24, r.width / 2), r.top + Math.min(r.height, 32), el, true);
        }
      }}
      onPointerDown={(e) => {
        if (!longPress || e.pointerType !== 'touch' || (e.target as HTMLElement).closest?.('[data-cm-panel]')) return;
        const { clientX: x, clientY: y, target } = e;
        cancelPress();
        press.current = { x, y, timer: window.setTimeout(() => openAt(x, y, target, false), 520) };
      }}
      onPointerMove={(e) => press.current && Math.hypot(e.clientX - press.current.x, e.clientY - press.current.y) > 10 && cancelPress()}
      onPointerUp={cancelPress}
      onPointerCancel={cancelPress}
      className={cn('relative rounded-xl outline-none [-webkit-touch-callout:none] focus-visible:outline-2 focus-visible:outline-offset-2 focus-visible:outline-solid focus-visible:outline-ring', className)}
    >
      {children}
      {mounted && at && (
        <MenuPanel
          items={items}
          area={areaRef}
          point={at}
          depth={0}
          label={heading ?? t.menu}
          title={heading}
          autoFocus={at.keyboard ? 'first' : at.preview ? 'skip' : 'none'}
          state={state}
          onChoose={(it) => choose(it, at.context)}
          onCloseAll={close}
          labels={t}
        />
      )}
    </div>
    <p id={`${id}-hint`} className={cn(showHint ? 'mt-3 flex items-start gap-1.5 text-[13px] text-pretty text-muted-foreground' : 'sr-only')}>
      {showHint && <Icon name="mouse" size={14} className="mt-0.5" />}
      {t.hint}
    </p>
    </>
  );
}

interface PanelProps {
  items: ContextMenuItem[];
  area?: React.RefObject<HTMLDivElement | null>;
  point?: Point;
  /** For a submenu: the item it belongs to */
  parent?: HTMLElement;
  depth: number;
  label: string;
  title?: string;
  autoFocus: 'first' | 'none' | 'skip';
  state: { checks: Record<string, boolean>; radios: Record<string, string> };
  /** true closes the whole menu */
  onChoose: (it: ContextMenuItem) => boolean;
  onCloseAll: (focusBack: boolean) => void;
  onBack?: () => void;
  labels: (typeof TEXTS)['en'];
}

function MenuPanel({ items, area, point, parent, depth, label, title, autoFocus, state, onChoose, onCloseAll, onBack, labels }: PanelProps) {
  const ref = useRef<HTMLDivElement>(null);
  const [pos, setPos] = useState<{ x: number; y: number; origin: string } | null>(null);
  const [sub, setSub] = useState<{ index: number; el: HTMLElement; focus: 'first' | 'none' } | null>(null);
  const [armed, setArmed] = useState<number | null>(null);
  const typed = useRef({ text: '', at: 0 });
  const hoverTimer = useRef<number | undefined>(undefined);

  const nodes = () => Array.from(ref.current?.querySelectorAll<HTMLElement>(':scope > [data-cm-item]:not([aria-disabled="true"])') ?? []);

  // Place it at the pointer or beside its parent item, flipped and clamped into the window
  useIsoLayoutEffect(() => {
    const place = () => {
      const el = ref.current;
      if (!el) return;
      const vw = document.documentElement.clientWidth;
      const vh = window.innerHeight;
      const w = el.offsetWidth;
      const h = el.offsetHeight;
      let x: number;
      let y: number;
      let ox = 'left';
      let oy = 'top';
      if (parent) {
        const r = parent.getBoundingClientRect();
        x = r.right + 2;
        y = r.top - 6;
        if (x + w > vw - MARGIN) {
          x = r.left - w - 2;
          ox = 'right';
        }
        // A narrow screen has no room on either side: the submenu covers its parent instead, a bit lower
        if (x < MARGIN) {
          x = Math.min(Math.max(r.left + 12, MARGIN), vw - MARGIN - w);
          y = r.bottom - 4;
          ox = 'left';
        }
      } else {
        const a = area?.current?.getBoundingClientRect();
        x = (a?.left ?? 0) + (point?.x ?? 0);
        y = (a?.top ?? 0) + (point?.y ?? 0);
        if (x + w > vw - MARGIN) {
          x = Math.max(MARGIN, x - w);
          ox = 'right';
        }
        if (y + h > vh - MARGIN && y - h >= MARGIN) {
          y -= h;
          oy = 'bottom';
        }
      }
      x = Math.min(Math.max(x, MARGIN), Math.max(MARGIN, vw - MARGIN - w));
      y = Math.min(Math.max(y, MARGIN), Math.max(MARGIN, vh - MARGIN - h));
      setPos({ x: Math.round(x), y: Math.round(y), origin: `${oy} ${ox}` });
    };
    place();
    window.addEventListener('scroll', place, true);
    window.addEventListener('resize', place);
    return () => {
      window.removeEventListener('scroll', place, true);
      window.removeEventListener('resize', place);
    };
  }, [parent, point?.x, point?.y]);

  useEffect(() => {
    const id = requestAnimationFrame(() => {
      if (autoFocus === 'first') nodes()[0]?.focus({ preventScroll: true });
      else if (autoFocus === 'none' && depth === 0) ref.current?.focus({ preventScroll: true });
    });
    return () => cancelAnimationFrame(id);
  }, []);

  // The root panel closes on Escape anywhere and on a press outside every panel
  useEffect(() => {
    if (depth !== 0) return;
    const onDown = (e: PointerEvent) => {
      if ((e.target as HTMLElement).closest?.('[data-cm-panel]')) return;
      onCloseAll(false);
    };
    const onBlurWindow = () => onCloseAll(false);
    // A menu opened for a preview has no focus yet, Escape still closes it
    const onKey = (e: KeyboardEvent) => e.key === 'Escape' && !ref.current?.contains(document.activeElement) && onCloseAll(false);
    document.addEventListener('keydown', onKey);
    document.addEventListener('pointerdown', onDown, true);
    window.addEventListener('blur', onBlurWindow);
    return () => {
      document.removeEventListener('pointerdown', onDown, true);
      document.removeEventListener('keydown', onKey);
      window.removeEventListener('blur', onBlurWindow);
    };
  }, [depth, onCloseAll]);

  useEffect(() => () => window.clearTimeout(hoverTimer.current), []);

  const move = (to: number | 'first' | 'last') => {
    const list = nodes();
    if (!list.length) return;
    const i = list.indexOf(document.activeElement as HTMLElement);
    if (i < 0 && typeof to === 'number') to = to > 0 ? 'first' : 'last';
    const n = to === 'first' ? 0 : to === 'last' ? list.length - 1 : (i + to + list.length) % list.length;
    list[n].focus({ preventScroll: true });
  };

  const activate = (it: ContextMenuItem, i: number, el: HTMLElement, keyboard: boolean) => {
    if (!isAction(it) || ('disabled' in it && it.disabled)) return;
    if (it.type === 'submenu') {
      setSub({ index: i, el, focus: keyboard ? 'first' : 'none' });
      return;
    }
    if ((it.type === undefined || it.type === 'item') && it.confirm && armed !== i) {
      setArmed(i);
      return;
    }
    if (onChoose(it)) onCloseAll(true);
  };

  const onKeyDown = (e: React.KeyboardEvent) => {
    e.stopPropagation();
    const list = nodes();
    const current = document.activeElement as HTMLElement;
    const index = Number(current?.dataset.index);
    const it = Number.isFinite(index) ? items[index] : undefined;
    if (e.key === 'ArrowDown') (e.preventDefault(), move(1));
    else if (e.key === 'ArrowUp') (e.preventDefault(), move(-1));
    else if (e.key === 'Home' || e.key === 'PageUp') (e.preventDefault(), move('first'));
    else if (e.key === 'End' || e.key === 'PageDown') (e.preventDefault(), move('last'));
    else if (e.key === 'ArrowRight' && it?.type === 'submenu') (e.preventDefault(), activate(it, index, current, true));
    else if (e.key === 'ArrowLeft' && onBack) (e.preventDefault(), onBack());
    else if (e.key === 'Escape') {
      e.preventDefault();
      if (onBack) onBack();
      else onCloseAll(true);
    } else if (e.key === 'Tab') {
      e.preventDefault();
      onCloseAll(true);
    } else if ((e.key === 'Enter' || e.key === ' ') && it) {
      e.preventDefault();
      activate(it, index, current, true);
    } else if (e.key.length === 1 && !e.ctrlKey && !e.metaKey && !e.altKey) {
      const now = Date.now();
      typed.current = { text: (now - typed.current.at > 600 ? '' : typed.current.text) + e.key.toLowerCase(), at: now };
      const start = list.indexOf(current);
      const ordered = [...list.slice(start + 1), ...list.slice(0, start + 1)];
      const hit = typed.current.text.length > 1 ? list.find((n) => n.dataset.label?.startsWith(typed.current.text)) : ordered.find((n) => n.dataset.label?.startsWith(typed.current.text));
      hit?.focus({ preventScroll: true });
    }
  };

  return createPortal(
    <div
      ref={ref}
      data-cm-panel=""
      role="menu"
      aria-label={label}
      aria-orientation="vertical"
      tabIndex={-1}
      onKeyDown={onKeyDown}
      onContextMenu={(e) => {
        e.preventDefault();
        e.stopPropagation();
      }}
      className={cn(
        'kitfx-cm fixed left-0 top-0 z-50 max-h-[calc(100dvh-16px)] min-w-56 max-w-[calc(100vw-16px)] overflow-y-auto overscroll-contain rounded-xl border border-border bg-popover p-1.5 text-popover-foreground shadow-[var(--highlight),var(--shadow-lg)] outline-none kit-no-scrollbar',
        depth > 0 && 'min-w-48',
      )}
      style={{ transform: `translate(${pos?.x ?? 0}px, ${pos?.y ?? 0}px)`, visibility: pos ? undefined : 'hidden', '--origin': pos?.origin } as React.CSSProperties}
    >
      <style href="kitfx-cm" precedence="default">
        {CSS}
      </style>
      {title && depth === 0 && (
        <div role="presentation" className="kitfx-cm-item -mx-1.5 -mt-1.5 mb-1.5 truncate border-b border-border px-4 py-2.5 text-[13px] font-medium text-foreground">
          {title}
        </div>
      )}
      {items.map((it, i) => {
        const order = { '--i': i } as React.CSSProperties;
        if (it.type === 'separator') return <div key={i} role="separator" className="kitfx-cm-item -mx-1.5 my-1.5 h-px bg-border" style={order} />;
        if (it.type === 'label')
          return (
            <div key={i} role="presentation" style={order} className="kitfx-cm-item px-2.5 pb-1 pt-2 text-[11px] font-medium uppercase tracking-[0.08em] text-subtle-foreground">
              {it.label}
            </div>
          );
        const isItem = it.type === undefined || it.type === 'item';
        const destructive = isItem && it.destructive;
        const isArmed = isItem && armed === i;
        const checked = it.type === 'checkbox' ? Boolean(state.checks[it.id]) : it.type === 'radio' ? state.radios[it.group] === it.value : undefined;
        const role = it.type === 'checkbox' ? 'menuitemcheckbox' : it.type === 'radio' ? 'menuitemradio' : 'menuitem';
        const icon = it.type === 'radio' ? undefined : it.icon;
        const shortcut = isItem || it.type === 'checkbox' ? it.shortcut : undefined;
        const open = sub?.index === i;
        const text = isArmed && isItem ? it.confirm! : it.label;
        return (
          <div
            key={i}
            role={role}
            tabIndex={-1}
            data-cm-item=""
            data-index={i}
            data-label={it.label.toLowerCase()}
            aria-disabled={it.disabled || undefined}
            aria-checked={checked}
            aria-haspopup={it.type === 'submenu' ? 'menu' : undefined}
            aria-expanded={it.type === 'submenu' ? open : undefined}
            aria-keyshortcuts={shortcut}
            style={order}
            onClick={(e) => activate(it, i, e.currentTarget, e.detail === 0)}
            onPointerMove={(e) => {
              if (e.pointerType !== 'mouse' || it.disabled) return;
              if (document.activeElement !== e.currentTarget) e.currentTarget.focus({ preventScroll: true });
              window.clearTimeout(hoverTimer.current);
              const el = e.currentTarget;
              if (it.type === 'submenu' && !open) hoverTimer.current = window.setTimeout(() => setSub({ index: i, el, focus: 'none' }), 140);
              else if (it.type !== 'submenu' && sub) hoverTimer.current = window.setTimeout(() => setSub(null), 220);
            }}
            onBlur={() => isArmed && setArmed(null)}
            className={cn(
              'kitfx-cm-item group/cm relative flex min-h-9 w-full cursor-pointer select-none items-center gap-2.5 rounded-md px-2.5 py-1.5 text-left text-sm text-foreground outline-none transition-colors max-sm:min-h-11',
              'focus:bg-accent aria-disabled:cursor-not-allowed aria-disabled:opacity-45',
              open && 'bg-accent',
              destructive && 'text-destructive focus:bg-[color-mix(in_oklab,var(--destructive)_10%,transparent)]',
              isArmed && 'bg-[color-mix(in_oklab,var(--destructive)_14%,transparent)] font-medium focus:bg-[color-mix(in_oklab,var(--destructive)_18%,transparent)]',
            )}
          >
            {(it.type === 'checkbox' || it.type === 'radio') && (
              <span aria-hidden className="grid size-4 shrink-0 place-items-center">
                <span className={cn('grid place-items-center transition-[scale,opacity] duration-200 ease-[cubic-bezier(0.34,1.56,0.64,1)] motion-reduce:transition-none', checked ? 'scale-100 opacity-100' : 'scale-50 opacity-0')}>
                  {it.type === 'checkbox' ? <Icon name="check" size={15} strokeWidth={2} /> : <span className="size-[7px] rounded-full bg-current" />}
                </span>
              </span>
            )}
            {icon && <Icon name={isArmed ? 'alert-circle' : icon} size={16} className={cn('shrink-0', destructive ? 'text-destructive' : 'text-muted-foreground group-focus/cm:text-foreground')} />}
            <span className="min-w-0 flex-1">
              <span className="block truncate">{text}</span>
              {isItem && it.description && !isArmed && <span className="block truncate text-xs text-muted-foreground">{it.description}</span>}
            </span>
            {shortcut && !isArmed && <span className="ms-4 shrink-0 text-xs tracking-wide text-subtle-foreground">{shortcut}</span>}
            {it.type === 'submenu' && <Icon name="chevron-right" size={15} className="ms-3 shrink-0 text-muted-foreground" />}
          </div>
        );
      })}
      {sub && items[sub.index]?.type === 'submenu' && (
        <MenuPanel
          items={(items[sub.index] as Extract<ContextMenuItem, { type: 'submenu' }>).items}
          parent={sub.el}
          depth={depth + 1}
          label={items[sub.index].type === 'submenu' ? (items[sub.index] as { label: string }).label : labels.menu}
          autoFocus={sub.focus}
          state={state}
          onChoose={onChoose}
          onCloseAll={onCloseAll}
          onBack={() => {
            const el = sub.el;
            setSub(null);
            el.focus({ preventScroll: true });
          }}
          labels={labels}
        />
      )}
    </div>,
    document.body,
  );
}