AI search

'use client';

import { Fragment, useEffect, useId, useRef, useState } from 'react';
import { cn, prefersReducedMotion, useInView, useTexts } from '@/lib/kit';
import { Icon, type IconName } from '@/components/ui/icon';
import { Reveal } from '@/components/ui/reveal';
import { Stagger } from '@/components/ui/motion';

export type AiSearchVariant = 'overview' | 'research-report' | 'structured-answer' | 'follow-up-thread';

export interface SearchResult {
  id: number;
  title: string;
  site: string;
  /** Shown as the visible address, e.g. "stadtwerke-nordheim.de › tarife" */
  path?: string;
  snippet: string;
  href?: string;
  date?: string;
}

export interface ResearchQuery {
  id: string;
  query: string;
  /** Sources found for it */
  found: number;
}

export interface ReportSection {
  id: string;
  heading: string;
  /** Text with [n] citations */
  text: string;
}

export interface AnswerTable {
  columns: string[];
  /** Each row: label and one cell per column, cells may end with [n] */
  rows: { label: string; cells: string[] }[];
  /** Index of the column that is the recommendation */
  pick?: number;
}

export interface ThreadTurn {
  id: string;
  question: string;
  /** Text with [n] citations, **bold** works */
  answer: string;
  sources?: number[];
}

export interface AiSearchProps {
  variant?: AiSearchVariant;
  title?: string;
  query?: string;
  /** overview and follow-up-thread: the AI summary, [n] cites a result */
  summary?: string;
  results?: SearchResult[];
  /** overview, research-report and structured-answer: how sure the answer is */
  confidence?: 'high' | 'medium' | 'low';
  /** research-report */
  queries?: ResearchQuery[];
  sections?: ReportSection[];
  /** research-report: sources read in total */
  read?: number;
  /** structured-answer */
  table?: AnswerTable;
  /** structured-answer: things to keep in mind, shown under the table */
  caveats?: string[];
  /** follow-up-thread */
  turns?: ThreadTurn[];
  related?: string[];
  /** overview and structured-answer: called with the query when the search is submitted */
  onSearch?: (query: string) => void;
  labels?: Partial<(typeof TEXTS)['en']>;
  className?: string;
}

const TEXTS = {
  en: {
    search: 'Search',
    overview: 'AI overview',
    more: 'Show more',
    less: 'Show less',
    results: 'Results',
    source: 'Source {n}',
    confidence_high: 'Sources agree',
    confidence_medium: 'Sources partly disagree',
    confidence_low: 'Few sources, check carefully',
    aiNote: 'Generated from the results below. It can be wrong.',
    helpful: 'Helpful',
    notHelpful: 'Not helpful',
    planning: 'Planning searches',
    reading: 'Reading sources',
    writing: 'Writing the report',
    
    readLabel: 'sources read',
    
    contents: 'Contents',
    
    report: 'Report',
    
    recommended: 'Fits best',
    caveats: 'Keep in mind',
    sources: 'Sources',
    sourceCount: '{n} sources',
    follow: 'Ask a follow-up',
    ask: 'Ask',
    related: 'People also ask',
    thinking: 'Searching',
    collapse: 'Collapse answer',
    expand: 'Expand answer',
    fallback: 'I looked through the same sources again. The short answer is that it depends on your tariff and how much hot water you use. Open the sources for the details.',
  },
  de: {
    search: 'Suchen',
    overview: 'KI-Übersicht',
    more: 'Mehr zeigen',
    less: 'Weniger zeigen',
    results: 'Ergebnisse',
    source: 'Quelle {n}',
    confidence_high: 'Quellen sind sich einig',
    confidence_medium: 'Quellen sind sich teils uneinig',
    confidence_low: 'Wenige Quellen, genau prüfen',
    aiNote: 'Aus den Ergebnissen unten erstellt. Kann falsch sein.',
    helpful: 'Hilfreich',
    notHelpful: 'Nicht hilfreich',
    planning: 'Plant die Suchen',
    reading: 'Liest Quellen',
    writing: 'Schreibt den Bericht',
    
    readLabel: 'Quellen gelesen',
    
    contents: 'Inhalt',
    
    report: 'Bericht',
    
    recommended: 'Passt am besten',
    caveats: 'Gut zu wissen',
    sources: 'Quellen',
    sourceCount: '{n} Quellen',
    follow: 'Nachfrage stellen',
    ask: 'Fragen',
    related: 'Andere fragen auch',
    thinking: 'Sucht',
    collapse: 'Antwort einklappen',
    expand: 'Antwort aufklappen',
    fallback: 'Ich habe dieselben Quellen noch einmal durchgesehen. Kurz gesagt hängt es von deinem Tarif und deinem Warmwasser ab. Die Details stehen in den Quellen.',
  },
};

type Texts = (typeof TEXTS)['en'];
type P = AiSearchProps & { t: Texts };
const fill = (s: string, v: Record<string, string | number>) => s.replace(/\{(\w+)\}/g, (_, k) => String(v[k] ?? ''));

const CSS =
  '@keyframes asr-up{from{opacity:0;transform:translateY(8px)}}@keyframes asr-pop{from{opacity:0;transform:scale(.9)}}@keyframes asr-dot{0%,80%,100%{opacity:.25}40%{opacity:1}}' +
  '@media (prefers-reduced-motion:no-preference){.asr-up{animation:asr-up .45s var(--ease-kit) var(--asr-d,0ms) both}.asr-pop{animation:asr-pop .35s var(--ease-kit) var(--asr-d,0ms) both}.asr-dot{animation:asr-dot 1.2s ease-in-out infinite}}';

function Style() {
  return (
    <style href="kit-ai-search" precedence="default">
      {CSS}
    </style>
  );
}

/* ------------------------------------------------------------------ */
/* Shared parts                                                        */
/* ------------------------------------------------------------------ */

function Stage({ title, children, className, wide }: { title?: string; children: React.ReactNode; className?: string; wide?: boolean }) {
  return (
    <section className={cn('kit-glow relative overflow-clip bg-surface py-12 sm:py-16 lg:py-20', className)}>
      <div className="kit-container">
        <div className={cn('mx-auto w-full', wide ? 'max-w-[68rem]' : 'max-w-[46rem]')}>
          {title && (
            <Reveal className="mb-5 sm:mb-6">
              <h2 className="text-balance text-[22px] font-semibold leading-tight tracking-[-0.02em] text-foreground sm:text-[26px]">{title}</h2>
            </Reveal>
          )}
          {children}
        </div>
      </div>
    </section>
  );
}

function SearchBar({ value, t, onSubmit }: { value?: string; t: Texts; onSubmit?: (q: string) => void }) {
  const [q, setQ] = useState(value ?? '');
  return (
    <form
      role="search"
      onSubmit={(e) => {
        e.preventDefault();
        onSubmit?.(q);
      }}
      className="flex items-center gap-2 rounded-2xl border border-border bg-card p-1.5 pl-4 shadow-[var(--highlight),var(--shadow-md)] focus-within:border-[color-mix(in_oklab,var(--primary)_50%,var(--border))] focus-within:shadow-[var(--highlight),var(--shadow-md),0_0_0_3px_color-mix(in_oklab,var(--primary)_16%,transparent)]"
    >
      <Icon name="search" size={18} className="shrink-0 text-muted-foreground" />
      <label className="min-w-0 flex-1">
        <span className="sr-only">{t.search}</span>
        <input type="search" value={q} onChange={(e) => setQ(e.target.value)} className="h-11 w-full bg-transparent text-[15px] text-foreground outline-none placeholder:text-subtle-foreground focus-visible:outline-none" />
      </label>
      <button type="submit" aria-label={t.search} className="grid size-11 shrink-0 place-items-center rounded-xl bg-primary text-primary-foreground hover:bg-[color-mix(in_oklab,var(--primary)_88%,var(--background))]">
        <Icon name="arrow-right" size={18} />
      </button>
    </form>
  );
}

const CONF: Record<'high' | 'medium' | 'low', { icon: IconName; cls: string }> = {
  high: { icon: 'check-circle', cls: 'text-success-foreground' },
  medium: { icon: 'alert-circle', cls: 'text-warning-foreground' },
  low: { icon: 'help-circle', cls: 'text-destructive' },
};

function Confidence({ level, t }: { level: 'high' | 'medium' | 'low'; t: Texts }) {
  const c = CONF[level];
  return (
    <span className={cn('inline-flex items-center gap-1.5 text-[12.5px] font-medium', c.cls)}>
      <Icon name={c.icon} size={14} />
      {t[`confidence_${level}`]}
    </span>
  );
}

const cite = 'inline-flex h-[1.3em] min-w-[1.3em] items-center justify-center rounded-[5px] px-1 align-[0.1em] text-[11px] font-semibold tabular-nums leading-none transition-colors';

/** Text with **bold** and [n] markers, the marker stays with the word before it */
function Cited({ text, onCite, active, t }: { text: string; onCite?: (n: number) => void; active?: number | null; t: Texts }) {
  const out: React.ReactNode[] = [];
  const re = /(\S*)\s?\[(\d+(?:\s*,\s*\d+)*)\]([.,;:!?]?)/g;
  let last = 0;
  let k = 0;
  const bold = (s: string) => s.split(/(\*\*[^*]+\*\*)/g).map((x, i) => (x.startsWith('**') ? <strong key={i} className="font-semibold text-foreground">{x.slice(2, -2)}</strong> : <Fragment key={i}>{x}</Fragment>));
  for (const m of text.matchAll(re)) {
    out.push(<Fragment key={k++}>{bold(text.slice(last, m.index))}</Fragment>);
    out.push(
      <span key={k++} className="whitespace-nowrap">
        {bold(m[1])}
        {m[3]}
        {m[2].split(',').map((n) => {
          const id = Number(n.trim());
          if (!onCite)
            return (
              <span key={id} aria-label={fill(t.source, { n: id })} className={cn(cite, 'ml-0.5 bg-[color-mix(in_oklab,var(--primary)_14%,var(--card))] text-[color-mix(in_oklab,var(--primary)_75%,var(--foreground))]')}>
                {id}
              </span>
            );
          return (
            <button key={id} type="button" aria-label={fill(t.source, { n: id })} onClick={() => onCite?.(id)} className={cn(cite, "relative ml-0.5 after:absolute after:-inset-x-1 after:-inset-y-4 after:content-['']", active === id ? 'bg-primary text-primary-foreground' : 'bg-[color-mix(in_oklab,var(--primary)_14%,var(--card))] text-[color-mix(in_oklab,var(--primary)_75%,var(--foreground))] hover:bg-[color-mix(in_oklab,var(--primary)_24%,var(--card))]')}>
              {id}
            </button>
          );
        })}
      </span>,
    );
    last = m.index! + m[0].length;
  }
  out.push(<Fragment key={k++}>{bold(text.slice(last))}</Fragment>);
  return <>{out}</>;
}

function Favicon({ site, id }: { site: string; id: number }) {
  const tone = ['--primary', '--info', '--success', '--warning', '--destructive'][(id - 1) % 5];
  return (
    <span aria-hidden className="grid size-6 shrink-0 place-items-center rounded-full text-[11px] font-semibold uppercase" style={{ background: `color-mix(in oklab, var(${tone}) 16%, var(--card))`, color: `color-mix(in oklab, var(${tone}) 72%, var(--foreground))` }}>
      {site.charAt(0)}
    </span>
  );
}

/* ------------------------------------------------------------------ */
/* overview                                                            */
/* ------------------------------------------------------------------ */

function Overview({ t, title, query, summary = '', results = [], confidence = 'high', onSearch, className }: P) {
  const [open, setOpen] = useState(false);
  const [active, setActive] = useState<number | null>(null);
  const [vote, setVote] = useState<'up' | 'down' | null>(null);
  // A search plays the overview in again, the results come from onSearch
  const [run, setRun] = useState(0);
  const go = (n: number) => {
    setActive(n);
    document.getElementById(`asr-r-${n}`)?.scrollIntoView({ behavior: prefersReducedMotion() ? 'auto' : 'smooth', block: 'center' });
  };
  const paras = summary.split(/\n{2,}/);
  return (
    <Stage title={title} className={className}>
      <Reveal>
        <SearchBar value={query} t={t} onSubmit={(q) => (onSearch?.(q), setRun((r) => r + 1), setVote(null))} />
      </Reveal>
      <Reveal delay={100}>
        <section key={run} aria-label={t.overview} className="asr-up relative mt-5 overflow-hidden rounded-2xl border border-[color-mix(in_oklab,var(--primary)_30%,var(--border))] bg-[linear-gradient(180deg,color-mix(in_oklab,var(--primary)_7%,var(--card)),var(--card)_40%)] shadow-[var(--highlight),var(--shadow-sm)]">
          <div className="flex flex-wrap items-center justify-between gap-2 px-4 pt-4 sm:px-5">
            <p className="flex items-center gap-1.5 text-[13px] font-semibold text-foreground">
              <Icon name="sparkle" size={15} className="text-primary" />
              {t.overview}
            </p>
            <Confidence level={confidence} t={t} />
          </div>
          <div className={cn('relative px-4 pt-3 sm:px-5', !open && 'max-h-[9.5rem] overflow-hidden')}>
            <div className="space-y-3 text-pretty text-[15px] leading-relaxed text-muted-foreground">
              {paras.map((p, i) => (
                <p key={i}>
                  <Cited text={p} t={t} onCite={go} active={active} />
                </p>
              ))}
            </div>
            {!open && <div aria-hidden className="pointer-events-none absolute inset-x-0 bottom-0 h-16 bg-[linear-gradient(to_top,var(--card),transparent)]" />}
          </div>
          <div className="flex flex-wrap items-center justify-between gap-2 px-4 pb-3 pt-2 sm:px-5">
            <button type="button" aria-expanded={open} onClick={() => setOpen((o) => !o)} className="inline-flex h-11 items-center gap-1 rounded-lg px-2 text-[13px] font-medium text-foreground hover:bg-accent sm:h-8">
              {open ? t.less : t.more}
              <Icon name="chevron-down" size={15} className={cn('transition-transform duration-300', open && 'rotate-180')} />
            </button>
            <span className="flex items-center gap-1">
              <span className="mr-1 text-[12px] text-subtle-foreground max-sm:hidden">{t.aiNote}</span>
              {(['up', 'down'] as const).map((v) => (
                <button key={v} type="button" aria-pressed={vote === v} aria-label={v === 'up' ? t.helpful : t.notHelpful} onClick={() => setVote(vote === v ? null : v)} className={cn('grid size-11 place-items-center rounded-lg transition-colors sm:size-8', vote === v ? 'bg-accent text-foreground' : 'text-muted-foreground hover:bg-accent hover:text-foreground')}>
                  <Icon name={v === 'up' ? 'thumbs-up' : 'thumbs-down'} size={15} />
                </button>
              ))}
            </span>
          </div>
          <p className="border-t border-border px-4 py-2 text-[12px] text-subtle-foreground sm:hidden">{t.aiNote}</p>
        </section>
      </Reveal>
      <h3 className="mb-2 mt-7 px-1 text-[12.5px] font-medium text-subtle-foreground">{t.results}</h3>
      <Stagger as="ol" step={60} className="space-y-1">
        {results.map((r) => (
          <li key={r.id} id={`asr-r-${r.id}`} className={cn('scroll-mt-24 rounded-xl px-3 py-3 transition-colors duration-500 sm:px-4', active === r.id ? 'bg-[color-mix(in_oklab,var(--primary)_8%,var(--card))] shadow-[0_0_0_1px_color-mix(in_oklab,var(--primary)_35%,transparent)]' : 'hover:bg-card/70')}>
            <div className="flex items-center gap-2">
              <Favicon site={r.site} id={r.id} />
              <span className="min-w-0">
                <span className="block truncate text-[13px] text-foreground">{r.site}</span>
                {r.path && <span className="block truncate text-[12px] text-muted-foreground">{r.path}</span>}
              </span>
              <span className={cn(cite, 'ml-auto shrink-0', active === r.id ? 'bg-primary text-primary-foreground' : 'bg-[color-mix(in_oklab,var(--foreground)_8%,transparent)] text-muted-foreground')}>{r.id}</span>
            </div>
            <a href={r.href ?? '#'} className="-mb-3 -mt-1.5 block py-3 text-[16.5px] font-medium leading-snug text-[color-mix(in_oklab,var(--primary)_80%,var(--foreground))] underline-offset-4 hover:underline">
              {r.title}
            </a>
            <p className="mt-1 text-pretty text-[14px] leading-relaxed text-muted-foreground">
              {r.date && <span className="text-subtle-foreground">{r.date} · </span>}
              {r.snippet}
            </p>
          </li>
        ))}
      </Stagger>
    </Stage>
  );
}

/* ------------------------------------------------------------------ */
/* research-report                                                     */
/* ------------------------------------------------------------------ */

function ResearchReport({ t, title, query, queries = [], sections = [], results = [], read = 0, confidence = 'medium', className }: P) {
  // phase 0 planning, 1 reading, 2 writing, 3 done. The server renders the finished report.
  const [phase, setPhase] = useState(3);
  const [count, setCount] = useState(read);
  const [ref, inView] = useInView<HTMLDivElement>('0px 0px -20% 0px');
  const started = useRef(false);
  const timers = useRef<number[]>([]);
  // Once started the run plays to the end, even when it scrolls out of view, and is only cleared on unmount
  useEffect(() => () => timers.current.forEach((x) => (window.clearTimeout(x), window.clearInterval(x))), []);
  useEffect(() => {
    if (!inView || started.current || prefersReducedMotion()) return;
    // The lock is set when the timer fires: strict mode clears the first timer and starts a second one
    const go = window.setTimeout(() => {
      started.current = true;
      setPhase(0);
      setCount(0);
      const id = window.setInterval(() => setCount((c) => (c >= read ? (window.clearInterval(id), c) : c + Math.max(1, Math.round(read / 12)))), 100);
      timers.current.push(window.setTimeout(() => setPhase(1), 500), window.setTimeout(() => setPhase(2), 1600), window.setTimeout(() => setPhase(3), 2200), id);
    }, 0);
    return () => window.clearTimeout(go);
  }, [inView, read]);
  const steps = [t.planning, t.reading, t.writing];
  const [src, setSrc] = useState<number | null>(null);
  const uid = useId();
  const toSource = (n: number) => {
    setSrc(n);
    document.getElementById(`${uid}-src-${n}`)?.scrollIntoView({ behavior: prefersReducedMotion() ? 'auto' : 'smooth', block: 'center' });
  };
  return (
    <Stage title={title} className={className} wide>
      <div ref={ref}>
        <Reveal>
          <p className="mb-4 flex items-start gap-2 rounded-xl border border-border bg-card px-4 py-3 text-[15px] text-foreground shadow-[var(--shadow-sm)]">
            <Icon name="search" size={17} className="mt-0.5 shrink-0 text-muted-foreground" />
            {query}
          </p>
        </Reveal>
        <div className="grid grid-cols-1 gap-4 lg:grid-cols-[19rem_minmax(0,1fr)] lg:items-start lg:gap-6">
          {/* The process: steps, sources counted and the searches it ran */}
          <Reveal delay={80} className="lg:sticky lg:top-6">
            <div className="rounded-2xl border border-border bg-card p-4 shadow-[var(--highlight),var(--shadow-sm)]">
              <ol className="space-y-2.5" aria-live="polite">
                {steps.map((s, i) => {
                  const st = phase > i ? 'done' : phase === i ? 'now' : 'next';
                  return (
                    <li key={s} className="flex items-center gap-2.5 text-[13.5px]">
                      <span className={cn('grid size-6 shrink-0 place-items-center rounded-full', st === 'done' ? 'bg-[color-mix(in_oklab,var(--success)_16%,var(--card))] text-success-foreground' : st === 'now' ? 'bg-[color-mix(in_oklab,var(--primary)_16%,var(--card))] text-primary' : 'border border-border text-subtle-foreground')}>
                        <Icon name={st === 'done' ? 'check' : st === 'now' ? 'loader' : 'circle'} size={13} className={cn(st === 'now' && 'animate-spin', st === 'next' && 'scale-50')} />
                      </span>
                      <span className={st === 'next' ? 'text-muted-foreground' : 'text-foreground'}>{s}</span>
                    </li>
                  );
                })}
              </ol>
              <p className="mt-4 border-t border-border pt-3 text-[13px] tabular-nums text-muted-foreground">
                <span className="text-[20px] font-semibold text-foreground">{Math.min(count, read)}</span> {t.readLabel}
              </p>
              <ul className="mt-3 space-y-1.5">
                {queries.map((q, i) => (
                  <li key={q.id} className="flex items-center gap-2 text-[12.5px]">
                    <Icon name="search" size={12} className="shrink-0 text-subtle-foreground" />
                    <span className="min-w-0 flex-1 truncate text-muted-foreground">{q.query}</span>
                    <span className={cn('shrink-0 tabular-nums text-subtle-foreground transition-opacity duration-300', phase < 1 && 'opacity-0')} style={{ transitionDelay: `${i * 250}ms` }}>
                      {q.found}
                    </span>
                  </li>
                ))}
              </ul>
            </div>
          </Reveal>
          <Reveal delay={160}>
            <article className="rounded-2xl border border-border bg-card p-5 shadow-[var(--highlight),var(--shadow-sm)] sm:p-7" aria-busy={phase < 3}>
              <div className="mb-5 flex flex-wrap items-center justify-between gap-2 border-b border-border pb-4">
                <p className="flex items-center gap-1.5 text-[13px] font-semibold text-foreground">
                  <Icon name="file-check" size={15} className="text-primary" />
                  {t.report}
                </p>
                {phase >= 3 ? (
                  <span className="asr-up">
                    <Confidence level={confidence} t={t} />
                  </span>
                ) : (
                  <span className="text-[12.5px] text-muted-foreground">{steps[Math.min(phase, 2)]}</span>
                )}
              </div>
              <nav aria-label={t.contents} className="mb-6 flex flex-wrap gap-1.5">
                {sections.map((s) => (
                  <a key={s.id} href={`#asr-s-${s.id}`} className="inline-flex min-h-9 items-center rounded-lg border border-border px-2.5 text-[12.5px] text-muted-foreground transition-colors hover:bg-accent hover:text-foreground max-sm:min-h-11">
                    {s.heading}
                  </a>
                ))}
              </nav>
              <div className="space-y-7">
                {sections.map((s, i) => (
                  <section key={s.id} id={`asr-s-${s.id}`} className={cn('scroll-mt-24 transition-[opacity,filter] duration-700 ease-[var(--ease-kit)]', phase < 3 && 'opacity-25 blur-[2px]')} style={{ transitionDelay: phase >= 3 ? `${i * 140}ms` : '0ms' }}>
                    <h3 className="text-[17px] font-semibold tracking-[-0.01em] text-foreground">{s.heading}</h3>
                    <p className="mt-2 text-pretty text-[15px] leading-relaxed text-muted-foreground">
                      <Cited text={s.text} t={t} onCite={toSource} active={src} />
                    </p>
                  </section>
                ))}
              </div>
              <div className="mt-7 border-t border-border pt-4">
                <p className="mb-2 text-[12.5px] font-medium text-subtle-foreground">{t.sources}</p>
                <ol className="grid grid-cols-1 gap-1.5 sm:grid-cols-2">
                  {results.map((r) => (
                    <li key={r.id} id={`${uid}-src-${r.id}`} className="scroll-mt-24">
                      <a href={r.href ?? '#'} className={cn('flex min-h-11 items-center gap-2 rounded-lg px-2 py-1.5 text-[13px] transition-colors duration-500 hover:bg-accent', src === r.id && 'bg-[color-mix(in_oklab,var(--primary)_8%,var(--card))]')}>
                        <span className={cn(cite, src === r.id ? 'bg-primary text-primary-foreground' : 'bg-[color-mix(in_oklab,var(--foreground)_8%,transparent)] text-muted-foreground')}>{r.id}</span>
                        <span className="min-w-0 flex-1 text-pretty leading-snug text-foreground line-clamp-2">{r.title}</span>
                      </a>
                    </li>
                  ))}
                </ol>
              </div>
            </article>
          </Reveal>
        </div>
      </div>
    </Stage>
  );
}

/* ------------------------------------------------------------------ */

function StructuredAnswer({ t, title, query, summary, table, caveats = [], results = [], confidence = 'medium', onSearch, className }: P) {
  const [active, setActive] = useState<number | null>(null);
  const [phone, setPhone] = useState(table?.pick ?? 0);
  const [run, setRun] = useState(0);
  const cols = table?.columns ?? [];
  const src = results.find((r) => r.id === active);
  return (
    <Stage title={title} className={className} wide>
      <Reveal>
        <SearchBar value={query} t={t} onSubmit={(q) => (onSearch?.(q), setRun((r) => r + 1))} />
      </Reveal>
      <Reveal delay={100}>
        <div key={run} className="asr-up mt-5 rounded-2xl border border-border bg-card shadow-[var(--highlight),var(--shadow-sm)]">
          <div className="flex flex-wrap items-center justify-between gap-2 border-b border-border px-4 py-3 sm:px-5">
            <p className="flex items-center gap-1.5 text-[13px] font-semibold text-foreground">
              <Icon name="sparkle" size={15} className="text-primary" />
              {t.overview}
            </p>
            <Confidence level={confidence} t={t} />
          </div>
          {summary && (
            <p className="px-4 pt-4 text-pretty text-[15px] leading-relaxed text-muted-foreground sm:px-5">
              <Cited text={summary} t={t} onCite={setActive} active={active} />
            </p>
          )}
          {/* Phones: one option at a time */}
          <div className="p-4 md:hidden">
            <div role="tablist" aria-label={t.overview} className="flex gap-1 rounded-xl bg-[color-mix(in_oklab,var(--foreground)_5%,transparent)] p-1">
              {cols.map((c, i) => (
                <button
                  key={c}
                  type="button"
                  role="tab"
                  aria-selected={phone === i}
                  tabIndex={phone === i ? 0 : -1}
                  onClick={() => setPhone(i)}
                  onKeyDown={(e) => {
                    const d = e.key === 'ArrowRight' ? 1 : e.key === 'ArrowLeft' ? -1 : 0;
                    if (!d) return;
                    e.preventDefault();
                    const n = (i + d + cols.length) % cols.length;
                    setPhone(n);
                    (e.currentTarget.parentElement?.children[n] as HTMLElement | undefined)?.focus();
                  }} className={cn('min-h-11 flex-1 truncate rounded-lg px-1.5 text-[12.5px] font-medium', phone === i ? 'bg-card text-foreground shadow-[var(--highlight),var(--shadow-sm)]' : 'text-muted-foreground')}>
                  {c}
                </button>
              ))}
            </div>
            <dl key={phone} role="tabpanel" className="asr-up mt-3 divide-y divide-border rounded-xl border border-border">
              {table?.pick === phone && (
                <div className="flex items-center gap-1.5 bg-[color-mix(in_oklab,var(--primary)_8%,var(--card))] px-3.5 py-2 text-[12.5px] font-medium text-[color-mix(in_oklab,var(--primary)_75%,var(--foreground))]">
                  <Icon name="star" size={13} />
                  {t.recommended}
                </div>
              )}
              {table?.rows.map((r) => (
                <div key={r.label} className="flex items-start justify-between gap-3 px-3.5 py-2.5 text-[13.5px]">
                  <dt className="shrink-0 text-muted-foreground">{r.label}</dt>
                  <dd className="text-right text-foreground">
                    <Cited text={r.cells[phone] ?? ''} t={t} onCite={setActive} active={active} />
                  </dd>
                </div>
              ))}
            </dl>
          </div>
          <div className="hidden p-5 md:block">
            <table className="w-full table-fixed border-separate border-spacing-0 text-left text-[14px]">
              <thead>
                <tr>
                  <th className="w-[24%] pb-2" />
                  {cols.map((c, i) => (
                    <th key={c} scope="col" className={cn('rounded-t-xl px-4 pb-2 pt-3 align-bottom font-semibold text-foreground', table?.pick === i && 'bg-[color-mix(in_oklab,var(--primary)_8%,var(--card))]')}>
                      {table?.pick === i && (
                        <span className="mb-1 flex items-center gap-1 text-[11.5px] font-medium text-[color-mix(in_oklab,var(--primary)_75%,var(--foreground))]">
                          <Icon name="star" size={12} />
                          {t.recommended}
                        </span>
                      )}
                      {c}
                    </th>
                  ))}
                </tr>
              </thead>
              <tbody>
                {table?.rows.map((r, ri) => (
                  <tr key={r.label} className="asr-up" style={{ '--asr-d': `${200 + ri * 70}ms` } as React.CSSProperties}>
                    <th scope="row" className="border-t border-border py-3 pr-3 align-top text-[13px] font-normal text-muted-foreground">
                      {r.label}
                    </th>
                    {r.cells.map((cell, ci) => (
                      <td key={ci} className={cn('border-t border-border px-4 py-3 align-top text-foreground', table?.pick === ci && 'bg-[color-mix(in_oklab,var(--primary)_8%,var(--card))]', table?.pick === ci && ri === (table?.rows.length ?? 0) - 1 && 'rounded-b-xl')}>
                        <Cited text={cell} t={t} onCite={setActive} active={active} />
                      </td>
                    ))}
                  </tr>
                ))}
              </tbody>
            </table>
          </div>
          {src && (
            <div key={src.id} className="asr-up mx-4 mb-4 flex items-start gap-3 rounded-xl border border-border bg-background/60 p-3.5 sm:mx-5" aria-live="polite">
              <Favicon site={src.site} id={src.id} />
              <div className="min-w-0">
                <a href={src.href ?? '#'} className="text-[13.5px] font-medium text-foreground underline-offset-4 hover:underline">
                  {src.title}
                </a>
                <p className="mt-0.5 text-[12.5px] leading-relaxed text-muted-foreground">
                  {src.site} · {src.snippet}
                </p>
              </div>
            </div>
          )}
          {caveats.length > 0 && (
            <div className="border-t border-border px-4 py-4 sm:px-5">
              <p className="mb-2 flex items-center gap-1.5 text-[13px] font-medium text-foreground">
                <Icon name="info" size={14} className="text-warning-foreground" />
                {t.caveats}
              </p>
              <ul className="space-y-1.5">
                {caveats.map((c) => (
                  <li key={c} className="relative pl-4 text-pretty text-[13.5px] leading-relaxed text-muted-foreground before:absolute before:left-1 before:top-[0.6em] before:size-1.5 before:rounded-full before:bg-warning">
                    {c}
                  </li>
                ))}
              </ul>
            </div>
          )}
        </div>
      </Reveal>
    </Stage>
  );
}

/* ------------------------------------------------------------------ */
/* follow-up-thread                                                    */
/* ------------------------------------------------------------------ */

function FollowUpThread({ t, title, turns: initial = [], results = [], related = [], className }: P) {
  const [turns, setTurns] = useState(initial);
  const [collapsed, setCollapsed] = useState<string[]>(initial.slice(0, -1).map((x) => x.id));
  const [q, setQ] = useState('');
  const [busy, setBusy] = useState(false);
  const seq = useRef(0);
  const ask = (question: string) => {
    if (!question.trim() || busy) return;
    setBusy(true);
    setQ('');
    const id = `f${++seq.current}`;
    setCollapsed(turns.map((x) => x.id));
    window.setTimeout(
      () => {
        setTurns((s) => [...s, { id, question, answer: t.fallback, sources: results.slice(0, 2).map((r) => r.id) }]);
        setBusy(false);
      },
      prefersReducedMotion() ? 0 : 1200,
    );
  };
  return (
    <Stage title={title} className={className}>
      <ol className="space-y-3">
        {turns.map((x, i) => {
          const shut = collapsed.includes(x.id);
          return (
            <li key={x.id} className={cn('rounded-2xl border border-border bg-card shadow-[var(--highlight),var(--shadow-sm)]', i === turns.length - 1 && 'asr-up')}>
              <button type="button" aria-expanded={!shut} aria-label={shut ? t.expand : t.collapse} onClick={() => setCollapsed((c) => (shut ? c.filter((y) => y !== x.id) : [...c, x.id]))} className="flex w-full items-start gap-3 px-4 py-3.5 text-left sm:px-5">
                <h3 className="min-w-0 flex-1 text-pretty text-[16px] font-semibold leading-snug text-foreground">{x.question}</h3>
                {shut && !!x.sources?.length && <span className="mt-0.5 shrink-0 text-[12px] tabular-nums text-muted-foreground">{fill(t.sourceCount, { n: x.sources.length })}</span>}
                <Icon name="chevron-down" size={17} className={cn('mt-0.5 shrink-0 text-muted-foreground transition-transform duration-300', !shut && 'rotate-180')} />
              </button>
              <div className={cn('grid transition-[grid-template-rows] duration-500 ease-[var(--ease-kit)] motion-reduce:transition-none', shut ? 'grid-rows-[0fr]' : 'grid-rows-[1fr]')}>
                <div className="overflow-hidden" inert={shut || undefined}>
                  <div className="px-4 pb-4 sm:px-5">
                    <p className="text-pretty text-[15px] leading-relaxed text-muted-foreground">
                      <Cited text={x.answer} t={t} />
                    </p>
                    {!!x.sources?.length && (
                      <div className="mt-3 flex flex-wrap gap-1.5">
                        {x.sources.map((n) => {
                          const r = results.find((y) => y.id === n);
                          return r ? (
                            <a key={n} href={r.href ?? '#'} className="inline-flex h-8 max-w-full items-center gap-1.5 rounded-full border border-border bg-background pl-0.5 pr-2.5 text-[12px] text-muted-foreground hover:text-foreground max-sm:h-11">
                              <Favicon site={r.site} id={r.id} />
                              <span className="truncate">{r.site}</span>
                            </a>
                          ) : null;
                        })}
                      </div>
                    )}
                  </div>
                </div>
              </div>
            </li>
          );
        })}
        {busy && (
          <li className="asr-up flex items-center gap-2 rounded-2xl border border-dashed border-border-strong px-5 py-4 text-[13.5px] text-muted-foreground" role="status">
            <Icon name="loader" size={15} className="animate-spin" />
            {t.thinking}
          </li>
        )}
      </ol>
      {related.length > 0 && (
        <Reveal delay={100}>
          <p className="mb-2 mt-6 px-1 text-[12.5px] font-medium text-subtle-foreground">{t.related}</p>
          <ul className="divide-y divide-border rounded-2xl border border-border bg-card">
            {related.map((r) => (
              <li key={r}>
                <button type="button" disabled={busy} onClick={() => ask(r)} className="flex min-h-12 w-full items-center gap-3 px-4 py-2.5 text-left text-[14px] text-foreground transition-colors hover:bg-accent/60 disabled:opacity-50 sm:px-5">
                  <Icon name="corner-down-left" size={15} className="shrink-0 rotate-180 text-muted-foreground" />
                  <span className="flex-1">{r}</span>
                  <Icon name="plus" size={15} className="shrink-0 text-muted-foreground" />
                </button>
              </li>
            ))}
          </ul>
        </Reveal>
      )}
      <form
        onSubmit={(e) => {
          e.preventDefault();
          ask(q);
        }}
        className="sticky bottom-4 mt-5 flex items-center gap-2 rounded-2xl border border-border bg-card/95 p-1.5 pl-4 shadow-[var(--highlight),var(--shadow-lg)] backdrop-blur focus-within:border-[color-mix(in_oklab,var(--primary)_50%,var(--border))] focus-within:shadow-[var(--highlight),var(--shadow-lg),0_0_0_3px_color-mix(in_oklab,var(--primary)_16%,transparent)]"
      >
        <label className="min-w-0 flex-1">
          <span className="sr-only">{t.follow}</span>
          <input value={q} onChange={(e) => setQ(e.target.value)} placeholder={t.follow} className="h-11 w-full bg-transparent text-[15px] text-foreground outline-none placeholder:text-subtle-foreground focus-visible:outline-none" />
        </label>
        <button type="submit" disabled={!q.trim() || busy} className="inline-flex h-11 shrink-0 items-center gap-1.5 rounded-xl bg-primary px-4 text-[13.5px] font-medium text-primary-foreground disabled:bg-[color-mix(in_oklab,var(--foreground)_8%,var(--card))] disabled:text-subtle-foreground">
          {t.ask}
        </button>
      </form>
    </Stage>
  );
}

/* ------------------------------------------------------------------ */

/**
 * AI search: results with an AI overview on top and citations that jump to
 * their result, a research run that turns into a report, an answer as a
 * comparison table with a recommendation and caveats, and a thread of
 * follow-up questions with related ones to tap.
 */
export function AiSearch({ variant = 'overview', labels, ...props }: AiSearchProps) {
  const t = useTexts(TEXTS, labels);
  const p: P = { ...props, t };
  const body = (() => {
    switch (variant) {
      case 'research-report':
        return <ResearchReport {...p} />;
      case 'structured-answer':
        return <StructuredAnswer {...p} />;
      case 'follow-up-thread':
        return <FollowUpThread key={JSON.stringify(props.turns)} {...p} />;
      default:
        return <Overview {...p} />;
    }
  })();
  return (
    <>
      <Style />
      {body}
    </>
  );
}