'use strict';

/* ── Instancias públicas SearXNG con JSON API (fallback si no hay Google CSE) ── */
const SEARX_INSTANCES = [
  'https://searx.be',
  'https://priv.au',
  'https://search.mdosch.de',
  'https://searxng.site',
];

async function searchSearX(instance, query) {
  const url = `${instance}/search?` + new URLSearchParams({
    q:          query,
    format:     'json',
    categories: 'general',
    language:   'es-ES',
  });

  const res = await fetch(url, {
    headers: {
      'User-Agent': 'resetea.net/1.0 (egosurfing privacy tool)',
      'Accept':     'application/json',
    },
    signal: AbortSignal.timeout(7000),
  });

  if (!res.ok) throw new Error(`HTTP ${res.status}`);
  const data = await res.json();
  return (data.results || []).map(r => ({
    title:   r.title   || '',
    url:     r.url     || '',
    snippet: r.content || '',
    engine:  r.engine  || 'web',
  }));
}

async function searchGoogle(query) {
  const url = 'https://www.googleapis.com/customsearch/v1?' + new URLSearchParams({
    key: process.env.GOOGLE_API_KEY,
    cx:  process.env.GOOGLE_CSE_ID,
    q:   query,
    num: 10,
    hl:  'es',
  });

  const res = await fetch(url, { signal: AbortSignal.timeout(7000) });
  if (!res.ok) {
    const err = await res.json().catch(() => ({}));
    throw new Error(err.error?.message || `HTTP ${res.status}`);
  }
  const data = await res.json();
  return (data.items || []).map(item => ({
    title:   item.title       || '',
    url:     item.link        || '',
    snippet: item.snippet     || '',
    engine:  'google',
  }));
}

function domainOf(rawUrl) {
  try { return new URL(rawUrl).hostname.replace(/^www\./, ''); }
  catch { return ''; }
}

module.exports = async (req, res) => {
  const { q } = req.query;

  if (!q || q.trim().length < 2)
    return res.status(400).json({ error: 'Introduce al menos 2 caracteres.' });

  if (q.trim().length > 300)
    return res.status(400).json({ error: 'Búsqueda demasiado larga.' });

  /* Si la query no tiene operadores especiales la ponemos entre comillas
     para forzar coincidencia exacta (ideal para nombre/email/alias). */
  const query = /[:"()]/.test(q) ? q.trim() : `"${q.trim()}"`;

  let raw = [];

  try {
    if (process.env.GOOGLE_API_KEY && process.env.GOOGLE_CSE_ID) {
      raw = await searchGoogle(query);
    } else {
      for (const inst of SEARX_INSTANCES) {
        try {
          raw = await searchSearX(inst, query);
          if (raw.length) break;
        } catch (e) {
          console.warn(`[egosearch] ${inst} falló:`, e.message);
        }
      }
    }
  } catch (e) {
    console.error('[egosearch] error final:', e.message);
    return res.status(502).json({ error: 'El servicio de búsqueda no está disponible ahora. Inténtalo de nuevo.' });
  }

  const results = raw.slice(0, 5).map(r => ({
    title:   r.title,
    url:     r.url,
    snippet: r.snippet,
    domain:  domainOf(r.url),
    engine:  r.engine,
  }));

  res.json({ results, query, total: raw.length });
};