Combobox for React

'use client';

import { useCallback, useEffect, useId, useMemo, useRef, useState } from 'react';
import { cn, useTexts } from '@/lib/kit';
import { Icon, type IconName } from '@/components/ui/icon';
import { CONTROL_HEIGHT, controlBox, useControl, useShake, withField, type ControlSize, type FieldOwnProps } from '@/components/ui/input';
import { ActiveMarker, LIST_STYLE, ListboxGroups, revealOption, unfold, type SelectOption } from '@/components/ui/select';
import { Floating, panelSurface, useDismiss, useMounted } from '@/components/ui/popover';

const TEXTS = {
  en: { empty: 'No match. Try another word.', clear: 'Clear', toggle: 'Show options', results: 'results', create: 'Create' },
  de: { empty: 'Kein Treffer. Versuch ein anderes Wort.', clear: 'Leeren', toggle: 'Optionen zeigen', results: 'Treffer', create: 'Anlegen' },
};

export interface ComboboxProps extends FieldOwnProps {
  options: SelectOption[];
  value?: string;
  defaultValue?: string;
  onValueChange?: (value: string) => void;
  /** Offer to create the typed text when nothing matches */
  onCreate?: (text: string) => void;
  placeholder?: string;
  size?: ControlSize;
  icon?: IconName;
  name?: string;
  id?: string;
  disabled?: boolean;
  required?: boolean;
  invalid?: boolean;
  /** Custom matching. Default: every word of the query appears in label or description. */
  filter?: (option: SelectOption, query: string) => boolean;
  /** Open on first render with this query, for demos */
  defaultQuery?: string;
  defaultOpen?: boolean;
  labels?: Partial<(typeof TEXTS)['en']>;
  className?: string;
}

const norm = (s: string) => s.toLowerCase().normalize('NFD').replace(/\p{Diacritic}/gu, '');
const defaultFilter = (o: SelectOption, q: string) => {
  const hay = norm(`${o.label} ${o.description ?? ''}`);
  return norm(q).split(/\s+/).filter(Boolean).every((w) => hay.includes(w));
};

/** Marks the typed part in a label */
function Highlight({ text, query }: { text: string; query: string }) {
  const q = norm(query.trim());
  if (!q) return <>{text}</>;
  const i = norm(text).indexOf(q.split(/\s+/)[0]);
  if (i < 0) return <>{text}</>;
  const len = q.split(/\s+/)[0].length;
  return (
    <>
      {text.slice(0, i)}
      <mark className="rounded-[3px] bg-[color-mix(in_oklab,var(--primary)_16%,transparent)] text-inherit">{text.slice(i, i + len)}</mark>
      {text.slice(i + len)}
    </>
  );
}

function ComboboxBox({ options, value: valueProp, defaultValue, onValueChange, onCreate, placeholder, size = 'md', icon = 'search', name, id, disabled, required, invalid, filter = defaultFilter, defaultQuery, defaultOpen, labels, className }: Omit<ComboboxProps, keyof FieldOwnProps>) {
  const t = useTexts(TEXTS, labels);
  const c = useControl({ id, invalid, disabled, required });
  const [inner, setInner] = useState(defaultValue);
  const value = valueProp ?? inner;
  const selected = options.find((o) => o.value === value);
  const [query, setQuery] = useState(defaultQuery ?? selected?.label ?? '');
  const [typing, setTyping] = useState(defaultQuery !== undefined);
  const [open, setOpen] = useState(Boolean(defaultOpen));
  const [active, setActive] = useState(0);
  const mounted = useMounted();
  const boxRef = useRef<HTMLDivElement>(null);
  const inputRef = useRef<HTMLInputElement>(null);
  const listRef = useRef<HTMLDivElement>(null);
  const baseId = useId();
  const listId = `${baseId}-list`;

  const shown = useMemo(() => (typing && query.trim() ? options.filter((o) => filter(o, query)) : options), [options, query, typing, filter]);
  const canCreate = Boolean(onCreate && typing && query.trim() && !options.some((o) => norm(o.label) === norm(query.trim())));
  const count = shown.length + (canCreate ? 1 : 0);

  const close = useCallback(() => {
    setOpen(false);
    setTyping(false);
    setQuery((q) => (selected ? selected.label : q));
  }, [selected]);
  const refs = useRef([boxRef, listRef]).current;
  useDismiss(open, close, refs);
  useShake(boxRef, c.invalid);

  useEffect(() => {
    if (open) revealOption(active < shown.length ? `${baseId}-opt-${active}` : `${baseId}-create`);
  }, [open, active, baseId, shown.length]);

  const pick = (o: SelectOption) => {
    if (o.disabled) return;
    setInner(o.value);
    onValueChange?.(o.value);
    setQuery(o.label);
    setTyping(false);
    setOpen(false);
  };
  const create = () => {
    onCreate?.(query.trim());
    setTyping(false);
    setOpen(false);
  };

  const onKeyDown = (e: React.KeyboardEvent) => {
    if (e.key === 'ArrowDown' || e.key === 'ArrowUp') {
      e.preventDefault();
      if (!open) {
        setOpen(true);
        setActive(Math.max(0, shown.findIndex((o) => o.value === value)));
        return;
      }
      setActive((a) => (a + (e.key === 'ArrowDown' ? 1 : -1) + count) % Math.max(count, 1));
    } else if (e.key === 'Enter' && open) {
      e.preventDefault();
      if (active < shown.length && shown[active]) pick(shown[active]);
      else if (canCreate) create();
    } else if (e.key === 'Escape') {
      if (open) close();
      else if (query) {
        setQuery('');
        setTyping(true);
      }
    } else if (e.key === 'Tab' && open) close();
  };

  const activeId = open && count ? (active < shown.length ? `${baseId}-opt-${active}` : `${baseId}-create`) : undefined;

  return (
    <>
      <div ref={boxRef} data-invalid={c.invalid || undefined} data-disabled={c.disabled || undefined} className={cn('group/combo relative flex w-full items-center', CONTROL_HEIGHT[size], controlBox, className)}>
        <Icon name={icon} size={16} className="pointer-events-none ms-3.5 shrink-0 text-subtle-foreground transition-colors duration-300 group-focus-within/combo:text-muted-foreground" />
        <input
          ref={inputRef}
          id={c.id}
          role="combobox"
          aria-autocomplete="list"
          aria-expanded={open}
          aria-controls={open ? listId : undefined}
          aria-activedescendant={activeId}
          aria-invalid={c['aria-invalid']}
          aria-describedby={c['aria-describedby']}
          disabled={c.disabled}
          required={c.required}
          autoComplete="off"
          spellCheck={false}
          placeholder={placeholder}
          value={query}
          onChange={(e) => {
            setQuery(e.target.value);
            setTyping(true);
            setActive(0);
            setOpen(true);
          }}
          onClick={() => setOpen(true)}
          onKeyDown={onKeyDown}
          className="h-full w-0 min-w-0 flex-1 bg-transparent ps-2.5 text-inherit outline-none placeholder:text-subtle-foreground"
        />
        {query && !c.disabled && (
          <button
            type="button"
            aria-label={t.clear}
            onClick={() => {
              setQuery('');
              setTyping(true);
              setOpen(true);
              inputRef.current?.focus();
            }}
            className="relative grid size-7 place-items-center rounded-md text-subtle-foreground transition-[background-color,color,scale] duration-200 after:absolute after:-inset-2 after:content-[''] hover:bg-accent hover:text-foreground active:scale-90 starting:scale-50 starting:opacity-0 motion-reduce:transition-none"
          >
            <Icon name="x" size={14} />
          </button>
        )}
        <button
          type="button"
          tabIndex={-1}
          aria-label={t.toggle}
          onClick={() => {
            setOpen(!open);
            inputRef.current?.focus();
          }}
          className="me-1.5 grid size-7 place-items-center rounded-md text-subtle-foreground transition-colors hover:bg-accent hover:text-foreground"
        >
          <Icon name="chevrons-up-down" size={15} className={cn('transition-[scale] duration-300 ease-[var(--ease-kit)]', open && 'scale-110')} />
        </button>
      </div>
      {name && <input type="hidden" name={name} value={value ?? ''} />}
      <span aria-live="polite" className="sr-only">
        {open && typing ? `${shown.length} ${t.results}` : ''}
      </span>
      {mounted && open && (
        <Floating anchor={boxRef} side="bottom" align="start" offset={6} matchWidth ref={listRef}>
          {(pos) => (
            <div
              id={listId}
              role="listbox"
              aria-labelledby={c.id}
              className={cn('kit-scrollbar relative max-h-72 overflow-y-auto overscroll-contain p-1.5', panelSurface, unfold(pos?.side).className)}
            >
              <style dangerouslySetInnerHTML={{ __html: LIST_STYLE }} />
              <ActiveMarker id={activeId} version={`${query}|${shown.length}`} />
              {shown.length > 0 && (
                <ListboxGroups
                  options={shown}
                  baseId={`${baseId}-opt`}
                  activeIndex={active}
                  isSelected={(o) => o.value === value}
                  onPick={pick}
                  onHover={(i) => setActive(i)}
                  render={(o) => <Highlight text={o.label} query={typing ? query : ''} />}
                />
              )}
              {canCreate && (
                <div
                  id={`${baseId}-create`}
                  role="option"
                  aria-selected={false}
                  data-active={active === shown.length || undefined}
                  onPointerMove={() => setActive(shown.length)}
                  onPointerDown={(e) => e.preventDefault()}
                  onClick={create}
                  style={{ '--i': shown.length } as React.CSSProperties}
                  className="kitfx-select-row relative flex min-h-9 cursor-pointer items-center gap-2.5 rounded-md px-2.5 text-sm text-foreground max-sm:min-h-11"
                >
                  <Icon name="plus" size={16} className="text-muted-foreground" />
                  <span className="truncate">
                    {t.create} <span className="font-medium">{query.trim()}</span>
                  </span>
                </div>
              )}
              {count === 0 && <p className="px-3 py-6 text-center text-sm text-muted-foreground">{t.empty}</p>}
            </div>
          )}
        </Floating>
      )}
    </>
  );
}

/**
 * A text field that filters a list as you type. Arrows move, Enter picks, Escape closes then clears.
 * Ignores accents and word order, highlights the match, can offer to create a new entry.
 *   <Combobox label="Country" options={countries} placeholder="Search a country" />
 */
export function Combobox({ label, hint, error, optional, labelAction, className, ...rest }: ComboboxProps) {
  const wrapped = Boolean(label || hint || error);
  return withField({ label, hint, error, optional, labelAction, id: rest.id, required: rest.required, disabled: rest.disabled, className }, <ComboboxBox {...rest} className={wrapped ? undefined : className} />);
}