React chips

'use client';

import { useEffect, useId, useRef, useState } from 'react';
import { cn, useLocale, useTexts } from '@/lib/kit';
import { Icon, type IconName } from '@/components/ui/icon';
import { Avatar } from '@/components/ui/avatar';
import { shrinkAway } from '@/components/ui/tag';

/*
 * Chips: compact, interactive tokens in four jobs, each with its own semantics.
 *
 *   input       things already chosen (recipients, applied filters). Every chip is
 *               a stop for the arrow keys, Delete or Backspace removes it, focus
 *               moves on to the neighbour and the removal is announced.
 *   filter      switch several on and off (aria-pressed), with counts.
 *   choice      exactly one of a set, as a listbox (aria-selected).
 *   suggestion  one press acts and the chip leaves (prompts, quick replies).
 *
 * Tags only label, a multi select picks from a long list in a field. Chips are
 * what a person presses right where they read.
 */

export type ChipsVariant = 'input' | 'filter' | 'choice' | 'suggestion';

export interface ChipItem {
  value: string;
  label: string;
  icon?: IconName;
  /** A person: initials from the name, or a drawn image */
  avatar?: { name: string; image?: React.ReactNode };
  /** Quiet number after the label */
  count?: number;
  disabled?: boolean;
}

const TEXTS = {
  en: { remove: 'Remove', removed: 'Removed', clearAll: 'Clear all', cleared: 'All removed', hint: 'Delete or Backspace removes it, the arrow keys move', selected: 'selected' },
  de: { remove: 'Entfernen', removed: 'Entfernt', clearAll: 'Alle entfernen', cleared: 'Alle entfernt', hint: 'Entf oder Rücktaste entfernt, Pfeiltasten wechseln', selected: 'ausgewählt' },
};
type ChipsTexts = (typeof TEXTS)['en'];

export interface ChipsProps {
  variant?: ChipsVariant;
  items: ChipItem[];
  /** Accessible name of the set, e.g. "Recipients" */
  label: string;
  /** filter: the pressed values. choice: the first entry is the chosen one. */
  value?: string[];
  defaultValue?: string[];
  onValueChange?: (value: string[]) => void;
  /** input: runs after a chip shrank away. Without it the chips keep their own list. */
  onRemove?: (value: string) => void;
  /** input: show a button that removes every chip */
  clearable?: boolean;
  onClear?: () => void;
  /** suggestion: runs with the value of the pressed chip */
  onSelect?: (value: string) => void;
  /** suggestion: the pressed chip leaves the row */
  dismissOnSelect?: boolean;
  size?: 'sm' | 'md';
  /** wrap: several lines. scroll: one line that scrolls sideways on narrow screens. */
  layout?: 'wrap' | 'scroll';
  /** scroll: on phones the row reaches into the padding of its surface by --chips-bleed (default 1rem), set it to that padding */
  /** filter and choice: the pressed chip in the accent color or quietly raised */
  tone?: 'accent' | 'neutral';
  labels?: Partial<ChipsTexts>;
  className?: string;
}

const SIZE = {
  sm: { chip: 'h-7 gap-1.5 px-2.5 text-[12px] after:-inset-y-2', icon: 13, avatar: '-ms-1.5', x: 'size-5 after:-inset-3', xi: 11 },
  md: { chip: 'h-8 gap-1.5 px-3 text-[13px]', icon: 14, avatar: '-ms-2', x: 'size-6 after:-inset-2.5', xi: 12 },
};

const BASE =
  'relative inline-flex shrink-0 cursor-pointer select-none items-center whitespace-nowrap rounded-full border font-medium leading-none outline-none transition-[background-color,border-color,color,box-shadow,scale,opacity] duration-200 ease-[var(--ease-kit)] focus-visible:outline-2 focus-visible:outline-offset-2 focus-visible:outline-solid focus-visible:outline-ring active:scale-[0.96] active:duration-100 motion-reduce:active:scale-100 aria-disabled:pointer-events-none aria-disabled:opacity-45 disabled:pointer-events-none disabled:opacity-45 ' +
  // The finger target reaches 44 px without making the chip itself taller
  'after:absolute after:inset-x-0 after:-inset-y-1.5 after:content-[""] after:rounded-full';

const IDLE = 'border-border-strong bg-background text-foreground shadow-[var(--shadow-sm)] hover:bg-accent';
const ON: Record<'accent' | 'neutral', string> = {
  accent: 'border-transparent bg-primary text-primary-foreground shadow-[inset_0_1px_0_rgb(255_255_255/0.16),var(--shadow-sm)]',
  neutral:
    'border-[color-mix(in_oklab,var(--foreground)_32%,var(--border-strong))] bg-[color-mix(in_oklab,var(--foreground)_9%,var(--background))] text-foreground shadow-[var(--shadow-sm)]',
};

/** A check that draws itself when a chip gets pressed */
function Check({ size }: { size: number }) {
  return (
    <svg viewBox="0 0 24 24" width={size} height={size} fill="none" aria-hidden className="shrink-0">
      <path
        d="m5 12.5 4.5 4.5L19 7.5"
        pathLength={1}
        stroke="currentColor"
        strokeWidth="2.4"
        strokeLinecap="round"
        strokeLinejoin="round"
        className="[stroke-dasharray:1] [stroke-dashoffset:0] transition-[stroke-dashoffset] duration-300 ease-[var(--ease-kit)] starting:[stroke-dashoffset:1] motion-reduce:transition-none"
      />
    </svg>
  );
}

function Lead({ item, size, pressed }: { item: ChipItem; size: 'sm' | 'md'; pressed?: boolean }) {
  const s = SIZE[size];
  if (item.avatar)
    return <Avatar name={item.avatar.name} image={item.avatar.image} alt="" size="xs" className={cn(s.avatar, size === 'sm' && 'size-5 text-[8px]')} />;
  if (pressed) return <Check size={s.icon} />;
  if (item.icon) return <Icon name={item.icon} size={s.icon} className="shrink-0 opacity-75" />;
  return null;
}

function Count({ n, on }: { n: number; on?: boolean }) {
  const locale = useLocale();
  return <span className={cn('tabular-nums', on ? 'opacity-80' : 'text-subtle-foreground')}>{new Intl.NumberFormat(locale === 'de' ? 'de-DE' : 'en-US').format(n)}</span>;
}

/** Moves focus between the chips of a row with the arrow keys, Home and End */
function roving(e: React.KeyboardEvent<HTMLElement>, selector: string) {
  const keys = ['ArrowRight', 'ArrowLeft', 'ArrowDown', 'ArrowUp', 'Home', 'End'];
  if (!keys.includes(e.key)) return false;
  const all = [...e.currentTarget.querySelectorAll<HTMLElement>(selector)].filter((el) => el.getAttribute('aria-disabled') !== 'true' && !(el as HTMLButtonElement).disabled);
  const i = all.indexOf(document.activeElement as HTMLElement);
  if (i < 0) return false;
  e.preventDefault();
  const fwd = e.key === 'ArrowRight' || e.key === 'ArrowDown';
  const next = e.key === 'Home' ? 0 : e.key === 'End' ? all.length - 1 : (i + (fwd ? 1 : -1) + all.length) % all.length;
  all[next]?.focus();
  all[next]?.scrollIntoView({ block: 'nearest', inline: 'nearest' });
  return true;
}

/** Compact interactive tokens: input chips to remove, filter chips to toggle, choice chips to pick one, suggestion chips to act. */
export function Chips({
  variant = 'filter',
  items,
  label,
  value,
  defaultValue,
  onValueChange,
  onRemove,
  clearable,
  onClear,
  onSelect,
  dismissOnSelect,
  size = 'md',
  layout = 'wrap',
  tone = 'accent',
  labels,
  className,
}: ChipsProps) {
  const t = useTexts(TEXTS, labels);
  const hintId = useId();
  const s = SIZE[size];

  // Own list for input and suggestion chips, refreshed when the items change from outside
  const signature = items.map((i) => `${i.value}\u0001${i.label}`).join('\u0002');
  const [list, setList] = useState(items);
  useEffect(() => setList(items), [signature]); // eslint-disable-line react-hooks/exhaustive-deps

  const [inner, setInner] = useState<string[]>(defaultValue ?? (variant === 'choice' && items[0] ? [items[0].value] : []));
  const selected = value ?? inner;
  const set = (next: string[]) => {
    if (value === undefined) setInner(next);
    onValueChange?.(next);
  };

  const [announce, setAnnounce] = useState('');
  const [focusIdx, setFocusIdx] = useState(0);
  const rowRef = useRef<HTMLDivElement>(null);
  const scroll = layout === 'scroll';
  const rowClass = cn(
    'flex items-center gap-2',
    scroll ? 'kit-no-scrollbar -my-3 flex-nowrap overflow-x-auto py-3 max-sm:-mx-[var(--chips-bleed,1rem)] max-sm:px-[var(--chips-bleed,1rem)] max-sm:kit-fade-end sm:flex-wrap sm:overflow-visible' : 'flex-wrap gap-y-2.5',
    className,
  );

  /* ---------- input ---------- */
  if (variant === 'input') {
    const remove = (v: string, el: HTMLElement | null, moveFocus: boolean) => {
      const idx = list.findIndex((x) => x.value === v);
      const item = list[idx];
      const chips = [...(rowRef.current?.querySelectorAll<HTMLElement>('[data-chip]') ?? [])];
      const neighbour = chips[idx + 1] ?? chips[idx - 1];
      shrinkAway(el, () => {
        setList((l) => l.filter((x) => x.value !== v));
        setAnnounce(`${t.removed}: ${item?.label ?? ''}`);
        onRemove?.(v);
        if (moveFocus) requestAnimationFrame(() => (neighbour?.isConnected ? neighbour : rowRef.current?.querySelector<HTMLElement>('[data-chip], [data-clear]'))?.focus());
        setFocusIdx(Math.max(0, Math.min(idx, list.length - 2)));
      });
    };
    return (
      <div className={cn(scroll ? '' : 'w-full')}>
        <div
          ref={rowRef}
          role="list"
          aria-label={label}
          onKeyDown={(e) => {
            if (roving(e, '[data-chip], [data-clear]')) return;
          }}
          className={rowClass}
        >
          {list.map((item, i) => (
            <div role="listitem" key={item.value} className="flex shrink-0">
              <span
                data-chip
                tabIndex={i === Math.min(focusIdx, list.length - 1) ? 0 : -1}
                aria-describedby={hintId}
                aria-disabled={item.disabled || undefined}
                onFocus={() => setFocusIdx(i)}
                onKeyDown={(e) => {
                  if ((e.key === 'Delete' || e.key === 'Backspace') && !item.disabled) {
                    e.preventDefault();
                    remove(item.value, e.currentTarget, true);
                  }
                }}
                className={cn(BASE, 'cursor-default pe-1', s.chip, IDLE, 'hover:bg-background focus-visible:bg-accent')}
              >
                <Lead item={item} size={size} />
                <span className="max-w-[14rem] truncate">{item.label}</span>
                {item.count !== undefined && <Count n={item.count} />}
                <button
                  type="button"
                  tabIndex={-1}
                  aria-label={`${t.remove}: ${item.label}`}
                  disabled={item.disabled}
                  onClick={(e) => remove(item.value, e.currentTarget.parentElement, false)}
                  className={cn(
                    // Above the finger target of the chip itself, which is drawn after it
                    'relative z-10 grid shrink-0 cursor-pointer place-items-center rounded-full text-muted-foreground transition-[background-color,color] hover:bg-[color-mix(in_oklab,var(--foreground)_12%,transparent)] hover:text-foreground after:absolute after:content-[""]',
                    s.x,
                  )}
                >
                  <Icon name="x" size={s.xi} strokeWidth={2.2} />
                </button>
              </span>
            </div>
          ))}
          {clearable && list.length > 1 && (
            <div role="listitem" className="flex shrink-0">
              <button
                type="button"
                data-clear
                onClick={() => {
                  setList([]);
                  setAnnounce(t.cleared);
                  onClear?.();
                }}
                className={cn(BASE, s.chip, 'border-transparent bg-transparent px-1.5 text-muted-foreground underline-offset-4 shadow-none hover:text-foreground hover:underline')}
              >
                {t.clearAll}
              </button>
            </div>
          )}
        </div>
        <span id={hintId} className="sr-only">
          {t.hint}
        </span>
        <span className="sr-only" aria-live="polite">
          {announce}
        </span>
      </div>
    );
  }

  /* ---------- choice: a listbox, one chosen ---------- */
  if (variant === 'choice') {
    const chosen = selected[0];
    const activeIdx = Math.max(0, list.findIndex((x) => x.value === chosen));
    return (
      <div
        ref={rowRef}
        role="listbox"
        aria-label={label}
        aria-orientation="horizontal"
        onKeyDown={(e) => roving(e, '[role="option"]')}
        className={rowClass}
      >
        {list.map((item, i) => {
          const on = item.value === chosen;
          const pick = () => !item.disabled && set([item.value]);
          return (
            <div
              key={item.value}
              role="option"
              aria-selected={on}
              aria-disabled={item.disabled || undefined}
              tabIndex={i === activeIdx ? 0 : -1}
              onClick={pick}
              onKeyDown={(e) => {
                if (e.key === ' ' || e.key === 'Enter') {
                  e.preventDefault();
                  pick();
                }
              }}
              className={cn(BASE, s.chip, on ? ON[tone] : IDLE)}
            >
              <Lead item={item} size={size} />
              {item.label}
              {item.count !== undefined && <Count n={item.count} on={on && tone === 'accent'} />}
            </div>
          );
        })}
      </div>
    );
  }

  /* ---------- suggestion: press acts, the chip may leave ---------- */
  if (variant === 'suggestion') {
    return (
      <div ref={rowRef} role="group" aria-label={label} onKeyDown={(e) => roving(e, 'button')} className={rowClass}>
        {list.map((item) => (
          <button
            key={item.value}
            type="button"
            disabled={item.disabled}
            onClick={(e) => {
              onSelect?.(item.value);
              if (!dismissOnSelect) return;
              const el = e.currentTarget;
              const next = (el.nextElementSibling ?? el.previousElementSibling) as HTMLElement | null;
              shrinkAway(el, () => {
                setList((l) => l.filter((x) => x.value !== item.value));
                requestAnimationFrame(() => next?.focus());
              });
            }}
            className={cn(
              BASE,
              s.chip,
              'border-[color-mix(in_oklab,var(--primary)_28%,var(--border))] bg-[color-mix(in_oklab,var(--primary)_6%,var(--background))] text-foreground hover:border-[color-mix(in_oklab,var(--primary)_50%,var(--border))] hover:bg-[color-mix(in_oklab,var(--primary)_11%,var(--background))]',
            )}
          >
            <Icon name={item.icon ?? 'sparkle'} size={s.icon} className="shrink-0 text-primary" />
            {item.label}
          </button>
        ))}
      </div>
    );
  }

  /* ---------- filter: toggle buttons ---------- */
  return (
    <div ref={rowRef} role="group" aria-label={label} onKeyDown={(e) => roving(e, 'button')} className={rowClass}>
      {list.map((item) => {
        const on = selected.includes(item.value);
        return (
          <button
            key={item.value}
            type="button"
            aria-pressed={on}
            disabled={item.disabled}
            onClick={() => set(on ? selected.filter((v) => v !== item.value) : [...selected, item.value])}
            className={cn(BASE, s.chip, on ? ON[tone] : IDLE)}
          >
            <Lead item={item} size={size} pressed={on && !item.avatar} />
            {item.label}
            {item.count !== undefined && <Count n={item.count} on={on && tone === 'accent'} />}
          </button>
        );
      })}
    </div>
  );
}