const path = require('path');
const fs = require('fs');
const { chromium } = require('playwright');

const DASHBOARD_DIR = path.join(__dirname, '..', 'dashboards');

let browser = null;

const USER_AGENT =
  'Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/137.0.0.0 Safari/537.36';

/** DDG-Redirect-URLs (duckduckgo.com/l/?uddg=...) auf die echte URL auflösen. */
function realUrl(href) {
  try {
    const u = new URL(href);
    if (u.hostname === 'duckduckgo.com' && u.pathname.startsWith('/l/') && u.searchParams.get('uddg')) {
      return u.searchParams.get('uddg');
    }
  } catch {}
  return href;
}

async function getBrowser() {
  if (!browser || !browser.isConnected()) {
    browser = await chromium.launch({
      channel: 'chromium',
      headless: true,
      args: ['--disable-blink-features=AutomationControlled', '--no-sandbox'],
    });
  }
  return browser;
}

async function withPage(url, fn) {
  const b = await getBrowser();
  const page = await b.newPage({ userAgent: USER_AGENT, viewport: { width: 1280, height: 900 } });
  try {
    return await fn(page);
  } finally {
    await page.close();
  }
}

async function goto(page, url, timeout = 30000) {
  let resp;
  try {
    resp = await page.goto(url, { waitUntil: 'domcontentloaded', timeout });
  } catch (e) {
    return { ok: false, error: `Navigation fehlgeschlagen: ${e.message.slice(0, 200)}` };
  }
  await page.waitForTimeout(1200);
  return {
    ok: resp ? resp.status() < 400 : true,
    status: resp ? resp.status() : 0,
    finalUrl: page.url(),
  };
}

/** DuckDuckGo HTML-Suche: Ergebnisse parsen. */
async function search(query, log) {
  const url = `https://duckduckgo.com/html/?q=${encodeURIComponent(query)}`;
  const results = await withPage(url, async (page) => {
    const nav = await goto(page, url);
    if (!nav.ok) return { nav, results: [], note: 'Suchseite nicht erreichbar' };

    await page.waitForTimeout(2500);
    const links = await page
      .locator('a.result__a')
      .evaluateAll((els) =>
        els.slice(0, 10).map((a) => ({
          title: (a.textContent || '').trim(),
          url: a.href,
        }))
      );
    for (const l of links) l.url = realUrl(l.url);

    const snippets = await page
      .locator('.result__snippet')
      .evaluateAll((els) => els.slice(0, 10).map((e) => (e.textContent || '').trim()));

    const blocked =
      (await page.title().catch(() => '')) === 'CAPTCHA' ||
      (await page.locator('text=CAPTCHA').count().catch(() => 0)) > 0;

    return {
      nav,
      blocked,
      results: links.map((l, i) => ({ ...l, snippet: snippets[i] || '' })),
    };
  });
  log?.(`Suche "${query}" -> ${results.results.length} Ergebnisse`);
  return results;
}

/** Seite besuchen und lesbaren Text extrahieren. */
async function browse(url, log) {
  return withPage(url, async (page) => {
    const nav = await goto(page, url);
    if (!nav.ok) return { nav, error: 'Seite konnte nicht geladen werden' };

    const data = await page.evaluate(() => {
      const title = document.title || '';
      const text = (document.body ? document.body.innerText : '').replace(/\s+\n/g, '\n');
      return { title, text: text.slice(0, 15000) };
    });
    log?.(`Besuche ${url} -> ${data.title}`);
    return { nav, title: data.title, text: data.text };
  });
}

/** Link prüfen: lädt die Seite erfolgreich und hat sie echten Inhalt? */
async function verify(url, log) {
  return withPage(url, async (page) => {
    const nav = await goto(page, url, 25000);
    if (!nav.ok) {
      log?.(`Verifizierung FEHLGESCHLAGEN (${nav.status || 'Timeout'}): ${url}`);
      return { url, ok: false, reason: `Seite lädt nicht (${nav.status || 'Timeout'})` };
    }
    const title = await page.title().catch(() => '');
    const bodyLen = await page.evaluate(() => document.body?.innerText?.length || 0).catch(() => 0);
    const badTitle = /404|not found|seite nicht gefunden|page not found/i.test(title);
    const ok = !badTitle && bodyLen > 200;
    log?.(`${ok ? 'VERIFIZIERT' : 'FEHLGESCHLAGEN'}: ${url}`);
    return {
      url,
      ok,
      reason: ok ? '' : badTitle ? 'Fehlerseite' : 'Kein nennenswerter Inhalt',
      title,
    };
  });
}

/** Dashboard als HTML-Datei speichern. Gibt den URL-Pfad zurück. */
function saveDashboard(sessionId, filename, html, log) {
  fs.mkdirSync(DASHBOARD_DIR, { recursive: true });
  const safeName = (filename || 'dashboard')
    .toLowerCase()
    .replace(/[^a-z0-9äöü-]+/g, '-')
    .replace(/^-+|-+$/g, '')
    .slice(0, 80) || 'dashboard';
  const file = `${sessionId}-${safeName}.html`;
  fs.writeFileSync(path.join(DASHBOARD_DIR, file), html, 'utf8');
  log?.(`Dashboard gespeichert: ${file}`);
  return { file, url: `/dashboards/${file}` };
}

/** Screenshot einer Seite (JPEG, als Data-URL) – für Vision-Modelle. */
async function screenshot(url, fullPage = false, log) {
  return withPage(url, async (page) => {
    const nav = await goto(page, url);
    if (!nav.ok) return { error: `Seite konnte nicht geladen werden (${nav.status || 'Timeout'})` };
    const title = await page.title().catch(() => '');
    let useFull = !!fullPage;
    if (useFull) {
      const h = await page.evaluate(() => document.body?.scrollHeight || 0).catch(() => 0);
      if (h > 6000) useFull = false;
    }
    const buf = await page.screenshot({ fullPage: useFull, type: 'jpeg', quality: 70 });
    log?.(`Screenshot: ${url}${useFull ? ' (voll)' : ''} – ${title || ''}`);
    return {
      title: title || nav.finalUrl || url,
      url: nav.finalUrl || url,
      image: `data:image/jpeg;base64,${buf.toString('base64')}`,
    };
  });
}

// ---------------------------------------------------------------------------
// Tour-Feature: Geocoding (Nominatim) + Routing (OSRM) + GPX-Export
// ---------------------------------------------------------------------------

const NOMINATIM_UA = 'ResearchChat/1.0 (Kontakt: research@localhost)';
let lastGeocodeTime = 0;

/** Koordinaten-Paare in OSRM-Format: lon,lat (ACHTUNG Reihenfolge). */
const toOsrm = (stops) => stops.map((s) => `${s.lon},${s.lat}`).join(';');

/** GPX-/XML-sichere Zeichen escapen. */
function xmlEscape(s) {
  return String(s ?? '')
    .replace(/&/g, '&amp;')
    .replace(/</g, '&lt;')
    .replace(/>/g, '&gt;')
    .replace(/"/g, '&quot;')
    .replace(/'/g, '&apos;');
}

/** Koordinaten-Angabe erkennen: "52.5163, 13.3777" oder "52.5163 13.3777". */
function parseCoords(query) {
  const m = String(query).match(/(-?\d{1,3}(?:\.\d+)?)\s*[,;\s]\s*(-?\d{1,3}(?:\.\d+)?)/);
  if (!m) return null;
  const lat = parseFloat(m[1]);
  const lon = parseFloat(m[2]);
  if (Math.abs(lat) <= 90 && Math.abs(lon) <= 180) return { lat, lon };
  return null;
}

/**
 * Ort über Nominatim (OpenStreetMap) in Koordinaten umwandeln.
 * Kostenlos, Fair-Use: max. 1 Request/Sekunde.
 */
async function geocode(query, config, log) {
  const coords = parseCoords(query);
  if (coords) {
    log?.(`Geocode "${query}" -> Koordinaten direkt übernommen`);
    return { ...coords, name: query, displayName: query, direct: true };
  }

  const wait = Math.max(0, lastGeocodeTime + 1100 - Date.now());
  if (wait > 0) await new Promise((r) => setTimeout(r, wait));
  lastGeocodeTime = Date.now();

  const url = new URL('https://nominatim.openstreetmap.org/search');
  url.searchParams.set('q', query);
  url.searchParams.set('format', 'json');
  url.searchParams.set('limit', '1');
  url.searchParams.set('accept-language', 'de');
  const headers = {
    'User-Agent': config?.nominatimEmail ? `ResearchChat/1.0 (${config.nominatimEmail})` : NOMINATIM_UA,
  };

  try {
    const resp = await fetch(url, { headers, timeout: 15000 });
    if (!resp.ok) return { error: `Nominatim Fehler ${resp.status}` };
    const results = await resp.json();
    if (!results.length) return { error: `Kein Ort gefunden: "${query}"` };
    const r = results[0];
    log?.(`Geocode "${query}" -> ${r.lat}, ${r.lon}`);
    return {
      name: r.name || query,
      lat: parseFloat(r.lat),
      lon: parseFloat(r.lon),
      displayName: r.display_name,
    };
  } catch (e) {
    return { error: `Nominatim nicht erreichbar: ${e.message.slice(0, 120)}` };
  }
}

/** Geometrie entschlacken (max. 500 Punkte für das Dashboard). */
function decimate(coords, max = 500) {
  if (coords.length <= max) return coords;
  const step = coords.length / max;
  const out = [];
  for (let i = 0; i < coords.length; i += step) out.push(coords[Math.floor(i)]);
  out.push(coords[coords.length - 1]);
  return out;
}

/**
 * Tour speichern: OSRM-Fuß-Route durch alle Stopps, GPX-Datei für OsmAnd,
 * tour.json für die Dashboard-Karte, Google-Maps-URLs.
 */
async function saveTour({ stops, title, filename, sessionId }, config, log) {
  if (!Array.isArray(stops) || stops.length < 2) {
    return { error: 'Mindestens 2 Stopps nötig (Name, lat, lon)' };
  }
  const clean = stops
    .filter((s) => s && s.name && Number.isFinite(Number(s.lat)) && Number.isFinite(Number(s.lon)))
    .map((s) => ({
      name: String(s.name).slice(0, 100),
      lat: Number(s.lat),
      lon: Number(s.lon),
      description: String(s.description || '').slice(0, 300),
    }));
  if (clean.length < 2) return { error: 'Stopps ungültig (Name + lat + lon erforderlich)' };

  // OSRM-Fuß-Route (Fallback: Luftlinie)
  let route = { coordinates: clean.map((s) => [s.lon, s.lat]), distanceKm: 0, durationMin: 0, source: 'line' };
  if (clean.length <= 25) {
    try {
      const osrmUrl = `${config?.osrmUrl || 'https://router.project-osrm.org'}/route/v1/foot/${toOsrm(clean)}?overview=full&geometries=geojson`;
      const resp = await fetch(osrmUrl, { timeout: 20000 });
      if (resp.ok) {
        const data = await resp.json();
        const r = data.routes?.[0];
        if (r?.geometry?.coordinates?.length) {
          route = {
            coordinates: decimate(r.geometry.coordinates), // für die Karte im Dashboard
            fullCoordinates: r.geometry.coordinates, // für die GPX-Datei (OsmAnd)
            distanceKm: Math.round((r.distance / 1000) * 10) / 10,
            durationMin: Math.round(r.duration / 60),
            source: 'osrm',
          };
        }
      } else {
        log?.(`OSRM antwortet ${resp.status} – Fallback: Luftlinie`);
      }
    } catch (e) {
      log?.(`OSRM nicht erreichbar – Fallback: Luftlinie (${e.message.slice(0, 80)})`);
    }
  }

  // GPX 1.1 bauen
  const wpts = clean
    .map(
      (s, i) =>
        `  <wpt lat="${s.lat.toFixed(6)}" lon="${s.lon.toFixed(6)}">\n` +
        `    <name>${xmlEscape(i + 1)}. ${xmlEscape(s.name)}</name>\n` +
        (s.description ? `    <desc>${xmlEscape(s.description)}</desc>\n` : '') +
        `  </wpt>`
    )
    .join('\n');
  const rtepts = clean
    .map((s) => `    <rtept lat="${s.lat.toFixed(6)}" lon="${s.lon.toFixed(6)}"><name>${xmlEscape(s.name)}</name></rtept>`)
    .join('\n');
  const trkpts = (route.fullCoordinates || route.coordinates)
    .map(([lon, lat]) => `      <trkpt lat="${lat.toFixed(6)}" lon="${lon.toFixed(6)}"></trkpt>`)
    .join('\n');
  const gpx = `<?xml version="1.0" encoding="UTF-8"?>
<gpx version="1.1" creator="ResearchChat" xmlns="http://www.topografix.com/GPX/1/1">
  <metadata>
    <name>${xmlEscape(title || 'Tour')}</name>
  </metadata>
${wpts}
  <rte>
    <name>${xmlEscape(title || 'Tour')}</name>
${rtepts}
  </rte>
  <trk>
    <name>${xmlEscape(title || 'Tour')} (Route)</name>
    <trkseg>
${trkpts}
    </trkseg>
  </trk>
</gpx>
`;

  const safeName =
    (filename || title || 'tour').toLowerCase().replace(/[^a-z0-9äöü-]+/g, '-').replace(/^-+|-+$/g, '').slice(0, 60) ||
    'tour';
  const base = `${sessionId}-${safeName.replace(/-tour$/, '')}-tour`;
  fs.mkdirSync(DASHBOARD_DIR, { recursive: true });
  fs.writeFileSync(path.join(DASHBOARD_DIR, `${base}.gpx`), gpx, 'utf8');
  const { fullCoordinates, ...routeForJson } = route;
  fs.writeFileSync(
    path.join(DASHBOARD_DIR, `${base}.tour.json`),
    JSON.stringify({
      title: title || 'Tour',
      stops: clean,
      route: routeForJson,
    }),
    'utf8'
  );

  const fmt = (lat, lon) => `${lat.toFixed(6)},${lon.toFixed(6)}`;
  const googleMapsUrl = `https://www.google.com/maps/dir/${clean.map((s) => fmt(s.lat, s.lon)).join('/')}/`;
  const stopsWithNav = clean.map((s) => ({
    ...s,
    navUrl: `https://www.google.com/maps/dir/?api=1&destination=${fmt(s.lat, s.lon)}&travelmode=walking`,
  }));

  log?.(
    `Tour gespeichert: ${base} (${clean.length} Stopps, ${route.distanceKm} km, ${route.durationMin} min, ${route.source})`
  );
  return {
    ok: true,
    title: title || 'Tour',
    gpxUrl: `/dashboards/${base}.gpx`,
    tourJsonUrl: `/dashboards/${base}.tour.json`,
    googleMapsUrl,
    stops: stopsWithNav,
    distanceKm: route.distanceKm,
    durationMin: route.durationMin,
    routeSource: route.source,
    osmAndHint: 'GPX-Datei herunterladen und in OsmAnd importieren (Menü → Meine Orte → Importieren).',
  };
}

async function closeBrowser() {
  if (browser) {
    await browser.close().catch(() => {});
    browser = null;
  }
}

module.exports = { search, browse, verify, saveDashboard, screenshot, geocode, saveTour, closeBrowser };