import { useEffect, useState } from 'react';
import { api } from '../../api.js';
import { BY_CODE, countryName, num, people } from './laender.js';

// Info-Kasten unten links auf der Karte: Land oder Stadt mit Fakten und Wikipedia-Text

const languageName = new Intl.DisplayNames(['de'], { type: 'language' });
const currencyName = new Intl.DisplayNames(['de'], { type: 'currency' });
const safe = (fn, v) => { try { return fn(v); } catch { return v; } };

function localTime(timezone) {
  try {
    return new Intl.DateTimeFormat('de-DE', { timeZone: timezone, hour: '2-digit', minute: '2-digit' }).format(new Date());
  } catch {
    return null;
  }
}

const infoCache = new Map();

function useInfo(params) {
  const query = new URLSearchParams(params).toString();
  const [info, setInfo] = useState(() => infoCache.get(query) || null);
  useEffect(() => {
    if (infoCache.has(query)) { setInfo(infoCache.get(query)); return; }
    let alive = true;
    api('GET', `/api/reisen/info?${query}`)
      .then((d) => { if (!d.offline) infoCache.set(query, d); if (alive) setInfo(d); })
      .catch(() => alive && setInfo({ offline: true }));
    return () => { alive = false; };
  }, [query]);
  return info;
}

export default function InfoCard({ selected, city, cities, otherCities, manual, busy, onSelect, onClose, onMark, onRemoveCity }) {
  if (selected.type === 'city' && city) {
    // Wer war (sichtbar) noch in dieser Stadt?
    const same = [...cities, ...otherCities].filter((c) => c.geonameId === city.geonameId && c.id !== city.id);
    return <CityInfo city={city} same={same} onSelect={onSelect} onClose={onClose} onRemove={onRemoveCity} busy={busy} />;
  }
  if (selected.type === 'country') {
    return (
      <CountryInfo
        code={selected.key}
        cities={cities.filter((c) => c.country === selected.key)}
        otherCities={otherCities.filter((c) => c.country === selected.key)}
        manual={manual.includes(selected.key)}
        onSelect={onSelect}
        onClose={onClose}
        onMark={onMark}
        busy={busy}
      />
    );
  }
  return null;
}

function Extract({ info }) {
  if (!info) return <p className="hint">Lade Infos …</p>;
  if (info.offline) return <p className="hint">Infotext gerade nicht erreichbar.</p>;
  if (!info.extract) return null;
  return (
    <>
      <p className="info-extract">{info.extract}</p>
      {info.url && <a className="info-more" href={info.url} target="_blank" rel="noopener noreferrer">Mehr bei Wikipedia ↗</a>}
    </>
  );
}

function CountryInfo({ code, cities, otherCities, manual, onSelect, onClose, onMark, busy }) {
  const c = BY_CODE.get(code);
  const name = countryName(code);
  const info = useInfo({ kind: 'land', name: c?.name || name, code });
  const visited = manual || cities.length > 0;
  const facts = [
    (info?.capital || c?.capital?.length) && ['Hauptstadt', info?.capital || c.capital.join(', ')],
    info?.population && ['Einwohner', `${people(info.population)}${info.populationYear ? ` (${info.populationYear})` : ''}`],
    c?.area && ['Fläche', `${num(Math.round(c.area))} km²`],
    c?.subregion && ['Region', c.subregion],
    c?.languages?.length && ['Sprachen', c.languages.map((l) => safe((x) => languageName.of(x), l)).join(', ')],
    c?.currencies?.length && ['Währung', c.currencies.map((x) => safe((y) => currencyName.of(y), x)).join(', ')],
  ].filter(Boolean);

  return (
    <aside className="info-card" aria-label={`Infos zu ${name}`}>
      <header className="info-head">
        <h2>{c?.flag} {name}</h2>
        <button className="link-btn" type="button" onClick={onClose} aria-label="Infos schließen">✕</button>
      </header>
      {c?.official && c.official !== name && <p className="info-sub">{c.official}</p>}
      <dl className="info-facts">
        {facts.map(([k, v]) => <div key={k}><dt>{k}</dt><dd>{v}</dd></div>)}
      </dl>
      <Extract info={info} />
      <div className="info-visit">
        <span className={`badge ${visited ? 'ok' : 'muted'}`}>{visited ? 'Besucht' : 'Noch nicht besucht'}</span>
        {cities.length > 0 ? (
          <span className="info-cities">
            {cities.map((city) => (
              <button key={city.id} type="button" className="chip" onClick={() => onSelect({ type: 'city', key: city.id })}>{city.name}</button>
            ))}
          </span>
        ) : (
          <button className="btn small" type="button" disabled={busy} onClick={() => onMark(code, !manual)}>
            {manual ? 'Markierung entfernen' : 'Als besucht markieren'}
          </button>
        )}
      </div>
      {cities.length > 0 && manual && (
        <button className="link-btn" type="button" disabled={busy} onClick={() => onMark(code, false)}>Zusätzliche Markierung entfernen</button>
      )}
      {otherCities.length > 0 && (
        <div className="info-others">
          <span className="hint">Andere waren hier:</span>
          <span className="info-cities">
            {otherCities.map((c) => <OtherChip key={c.id} city={c} onSelect={onSelect} />)}
          </span>
        </div>
      )}
    </aside>
  );
}

function OtherChip({ city, onSelect, label = city.name }) {
  return (
    <button type="button" className="chip travel-person active" style={{ '--dot': `var(--other-${city.color})` }} onClick={() => onSelect({ type: 'city', key: city.id })}>
      <span className="legend-dot" aria-hidden="true" />
      {label}
    </button>
  );
}

function CityInfo({ city, same, onSelect, onClose, onRemove, busy }) {
  const c = BY_CODE.get(city.country);
  const info = useInfo({ kind: 'stadt', name: city.name, code: String(city.geonameId), lat: city.lat, lon: city.lon });
  const time = city.timezone && localTime(city.timezone);
  const facts = [
    city.admin1 && ['Region', city.admin1],
    city.population && ['Einwohner', people(city.population)],
    city.elevation != null && ['Höhe', `${num(Math.round(city.elevation))} m`],
    time && ['Ortszeit', `${time} Uhr`],
  ].filter(Boolean);

  return (
    <aside className="info-card" aria-label={`Infos zu ${city.name}`}>
      <header className="info-head">
        <h2>{city.name}</h2>
        <button className="link-btn" type="button" onClick={onClose} aria-label="Infos schließen">✕</button>
      </header>
      <p className="info-sub">
        <button type="button" className="chip" onClick={() => onSelect({ type: 'country', key: city.country })}>
          {c?.flag} {countryName(city.country)}
        </button>
      </p>
      <dl className="info-facts">
        {facts.map(([k, v]) => <div key={k}><dt>{k}</dt><dd>{v}</dd></div>)}
      </dl>
      <Extract info={info} />
      <div className="info-visit">
        {city.owner ? (
          <span className="badge travel-owner" style={{ '--dot': `var(--other-${city.color})` }}>Besucht von {city.owner.name}</span>
        ) : (
          <>
            <span className="badge ok">Besucht</span>
            <button className="link-btn danger" type="button" disabled={busy} onClick={() => onRemove(city)}>Stadt entfernen</button>
          </>
        )}
      </div>
      {same.length > 0 && (
        <div className="info-others">
          <span className="hint">Auch hier:</span>
          <span className="info-cities">
            {same.map((c) => (c.owner
              ? <OtherChip key={c.id} city={c} onSelect={onSelect} label={c.owner.name} />
              : <button key={c.id} type="button" className="chip" onClick={() => onSelect({ type: 'city', key: c.id })}>Du</button>))}
          </span>
        </div>
      )}
    </aside>
  );
}