const express = require('express');
const https   = require('https');
const http    = require('http');
const db      = require('../db');
const { authenticate } = require('../middleware/auth');
const router  = express.Router();

const safe    = fn => { try { return fn(); } catch { return []; } };
const safeGet = fn => { try { return fn(); } catch { return null; } };

// ── iCal Fetch + Parse ────────────────────────────────────────────────────────
function fetchIcal(url) {
  return new Promise(resolve => {
    try {
      const parsed = new URL(url);
      const lib = parsed.protocol === 'https:' ? https : http;
      const req = lib.get(url, {
        headers: { 'User-Agent': 'Mozilla/5.0 DickenDock/1.0', 'Accept': 'text/calendar,*/*' }
      }, res => {
        // Redirects verfolgen
        if ([301,302,303,307,308].includes(res.statusCode) && res.headers.location) {
          res.destroy();
          const next = res.headers.location.startsWith('http')
            ? res.headers.location : new URL(res.headers.location, url).href;
          fetchIcal(next).then(resolve);
          return;
        }
        let data = '';
        res.on('data', d => { data += d; if (data.length > 1e6) { res.destroy(); resolve(null); } });
        res.on('end', () => resolve(data.includes('BEGIN:VCALENDAR') ? data : null));
      });
      req.on('error', () => resolve(null));
      req.setTimeout(10000, () => { req.destroy(); resolve(null); });
    } catch { resolve(null); }
  });
}

function parseIcal(raw) {
  const events = [];
  const parts = raw.split('BEGIN:VEVENT');
  for (let i = 1; i < parts.length; i++) {
    const b = parts[i];
    const get = key => {
      // Handle folded lines and key variants like DTSTART;TZID=...
      const m = b.match(new RegExp(key + '[^:]*:([^\\r\\n]+)'));
      return m ? m[1].replace(/\\n/g,' ').replace(/\\,/g,',').replace(/\\;/g,';').trim() : '';
    };
    const summary = get('SUMMARY');
    if (!summary) continue;
    events.push({ summary, description:get('DESCRIPTION'), location:get('LOCATION'), start:get('DTSTART'), end:get('DTEND') });
  }
  return events;
}

// ── Kalender-Sync Endpoint (POST /api/search/sync-calendar) ──────────────────
// Frontend ruft das beim Dashboard-Laden auf — kein Sync beim Suchen selbst
router.post('/sync-calendar', authenticate, async (req, res) => {
  const uid = req.user.id;
  const force = req.body?.force === true;

  const feeds = safeGet(() => db.prepare('SELECT * FROM calendar_feeds WHERE user_id=?').all(uid)) || [];
  if (!feeds.length) return res.json({ ok: true, synced: 0, message: 'Keine Kalender-Abos vorhanden' });

  // Alter des Caches prüfen
  // Alte Cache-Prüfung: Wenn noch historische Events drin (start_dt < 2000), force-sync
  const hasOldData = safeGet(() =>
    db.prepare("SELECT 1 FROM calendar_event_cache WHERE user_id=? AND start_dt < '20200101' LIMIT 1").get(uid)
  );
  if (!force && !hasOldData) {
    const lastSync = safeGet(() =>
      db.prepare("SELECT MAX(synced_at) as s FROM calendar_event_cache WHERE user_id=?").get(uid)?.s
    );
    if (lastSync && (Date.now() - new Date(lastSync).getTime()) < 10 * 60 * 1000) {
      return res.json({ ok: true, synced: 0, message: 'Cache noch frisch' });
    }
  }

  let totalSynced = 0;
  const errors = [];

  for (const feed of feeds) {
    try {
      const raw = await fetchIcal(feed.url);
      if (!raw) { errors.push(`${feed.name}: kein gültiger iCal-Feed`); continue; }
      const events = parseIcal(raw);
      if (!events.length) { errors.push(`${feed.name}: 0 Events geparst`); continue; }

      // Nur zukünftige Events speichern (ab gestern rückwärts 1 Tag für Tagesevents)
      // start_dt Format: YYYYMMDD oder YYYYMMDDTHHmmssZ → string-vergleichbar
      const yesterday = new Date();
      yesterday.setDate(yesterday.getDate() - 1);
      const minDt = yesterday.toISOString().replace(/-/g,'').slice(0,8); // '20260604'
      const futureEvents = events.filter(ev => !ev.start || ev.start >= minDt);

      // prepare INSIDE try-catch – wirft wenn Tabelle nicht existiert
      const ins = db.prepare(`
        INSERT INTO calendar_event_cache
        (feed_id, user_id, summary, description, location, start_dt, end_dt, synced_at)
        VALUES (?,?,?,?,?,?,?,datetime('now','localtime'))
      `);
      db.transaction(() => {
        db.prepare('DELETE FROM calendar_event_cache WHERE feed_id=?').run(feed.id);
        futureEvents.slice(0, 500).forEach(ev =>
          ins.run(feed.id, uid, ev.summary||'', ev.description||'', ev.location||'', ev.start||'', ev.end||'')
        );
      })();
      totalSynced += futureEvents.length;
    } catch(e) {
      console.error(`[CalendarSync] Feed "${feed.name}" (${feed.url}): ${e.message}`);
      errors.push(`${feed.name}: ${e.message}`);
    }
  }

  console.log(`[CalendarSync] uid=${uid} synced=${totalSynced} feeds=${feeds.length} errors=${errors.length}`);
  res.json({ ok: true, synced: totalSynced, feeds: feeds.length, errors });
});

// ── Suche ─────────────────────────────────────────────────────────────────────
router.get('/', authenticate, (req, res) => {
  const q   = (req.query.q || '').trim();
  const uid = req.user.id;

  if (q.length < 2) return res.json({
    links:[], folders:[], snippets:[], calculations:[], orders:[],
    todos:[], notes:[], board_items:[], changelog:[],
    files:[], file_folders:[], push_schedules:[],
    calendar_feeds:[], calendar_events:[], qr_codes:[]
  });

  const like = `%${q.toLowerCase()}%`;

  const links = safe(() => db.prepare(`
    SELECT id, title, url, icon, description FROM link_list
    WHERE user_id=? AND (LOWER(title) LIKE ? OR LOWER(url) LIKE ? OR LOWER(description) LIKE ?)
    ORDER BY title LIMIT 8
  `).all(uid, like, like, like));

  const folders = safe(() => db.prepare(`
    SELECT id, name, icon FROM link_list_folders
    WHERE user_id=? AND LOWER(name) LIKE ? ORDER BY name LIMIT 5
  `).all(uid, like));

  const snippets = safe(() => db.prepare(`
    SELECT id, title, description, language FROM snippets
    WHERE user_id=? AND (LOWER(title) LIKE ? OR LOWER(description) LIKE ?)
    ORDER BY title LIMIT 6
  `).all(uid, like, like));

  const calculations = safe(() => db.prepare(`
    SELECT id, name FROM calculations
    WHERE user_id=? AND LOWER(name) LIKE ? ORDER BY name LIMIT 5
  `).all(uid, like));

  const orders = safe(() => db.prepare(`
    SELECT id, name, status FROM orders
    WHERE user_id=? AND LOWER(name) LIKE ? ORDER BY name LIMIT 5
  `).all(uid, like));

  const todos = safe(() => db.prepare(`
    SELECT id, text, done FROM todos
    WHERE user_id=? AND LOWER(text) LIKE ?
    ORDER BY done, created_at DESC LIMIT 6
  `).all(uid, like));

  const noteRow = safeGet(() => db.prepare(
    'SELECT content FROM notes WHERE user_id=? AND LOWER(content) LIKE ?'
  ).get(uid, like));
  const notes = noteRow ? [(() => {
    const idx = noteRow.content.toLowerCase().indexOf(q.toLowerCase());
    const s = Math.max(0, idx - 30);
    return { id:'note', preview: (s>0?'…':'') + noteRow.content.slice(s, idx+60) + '…' };
  })()] : [];

  const board_items = safe(() => db.prepare(`
    SELECT id, title, description, type FROM board_items
    WHERE user_id=? AND (LOWER(title) LIKE ? OR LOWER(description) LIKE ?)
    ORDER BY created_at DESC LIMIT 5
  `).all(uid, like, like));

  const changelog = safe(() => db.prepare(`
    SELECT id, version, title, body FROM changelog
    WHERE LOWER(title) LIKE ? OR LOWER(body) LIKE ?
    ORDER BY created_at DESC LIMIT 4
  `).all(like, like));

  const files = safe(() => db.prepare(`
    SELECT id, originalname, mimetype, size FROM files
    WHERE user_id=? AND (LOWER(originalname) LIKE ? OR LOWER(filename) LIKE ?)
    ORDER BY originalname LIMIT 6
  `).all(uid, like, like));

  const file_folders = safe(() => db.prepare(`
    SELECT id, name FROM folders
    WHERE user_id=? AND LOWER(name) LIKE ? ORDER BY name LIMIT 5
  `).all(uid, like));

  const push_schedules = safe(() => db.prepare(`
    SELECT id, message, scheduled_at FROM push_schedules
    WHERE user_id=? AND LOWER(message) LIKE ? AND sent=0
    ORDER BY scheduled_at LIMIT 5
  `).all(uid, like));

  const calendar_feeds = safe(() => db.prepare(`
    SELECT id, name, url FROM calendar_feeds
    WHERE user_id=? AND (LOWER(name) LIKE ? OR LOWER(url) LIKE ?)
    ORDER BY name LIMIT 4
  `).all(uid, like, like));

  const calendar_events = safe(() => db.prepare(`
    SELECT c.id, c.summary, c.description, c.location, c.start_dt, f.name as feed_name
    FROM calendar_event_cache c
    JOIN calendar_feeds f ON f.id=c.feed_id
    WHERE c.user_id=? AND f.user_id=?
      AND (LOWER(c.summary) LIKE ? OR LOWER(c.description) LIKE ? OR LOWER(c.location) LIKE ?)
      AND c.start_dt >= strftime('%Y%m%d', 'now')
    ORDER BY c.start_dt LIMIT 8
  `).all(uid, uid, like, like, like));

  const qr_codes = safe(() => db.prepare(`
    SELECT id, label, url FROM qr_codes
    WHERE user_id=? AND (LOWER(label) LIKE ? OR LOWER(url) LIKE ?)
    ORDER BY created_at DESC LIMIT 5
  `).all(uid, like, like));

  // Gebietseroberung-Spiele
  const geo_games = safe(() => db.prepare(`
    SELECT g.id, u1.username as owner_name, u2.username as opp_name, g.status, g.current_turn
    FROM geo_games g
    JOIN users u1 ON u1.id=g.owner_id
    JOIN users u2 ON u2.id=g.opponent_id
    WHERE (g.owner_id=? OR g.opponent_id=?)
      AND (LOWER(u1.username) LIKE ? OR LOWER(u2.username) LIKE ?)
    ORDER BY g.updated_at DESC LIMIT 5
  `).all(uid, uid, like, like));

  // Andere Benutzer – für Chat-Navigation (nur Benutzernamen, keine sensiblen Daten)
  const users = safe(() => db.prepare(`
    SELECT id, username FROM users
    WHERE id != ? AND LOWER(username) LIKE ?
    ORDER BY username LIMIT 5
  `).all(uid, like));

  res.json({ links, folders, snippets, calculations, orders, todos, notes,
    board_items, changelog, files, file_folders, push_schedules,
    calendar_feeds, calendar_events, qr_codes, users, geo_games });
});

// Debug-Endpoint: Kalender-Cache inspizieren
router.get('/calendar-debug', authenticate, (req, res) => {
  const uid = req.user.id;
  const count   = db.prepare('SELECT COUNT(*) as n FROM calendar_event_cache WHERE user_id=?').get(uid);
  const samples = db.prepare('SELECT summary, start_dt FROM calendar_event_cache WHERE user_id=? ORDER BY start_dt LIMIT 10').all(uid);
  const today   = db.prepare("SELECT strftime('%Y%m%d','now') as d").get();
  const future  = db.prepare("SELECT COUNT(*) as n FROM calendar_event_cache WHERE user_id=? AND start_dt >= strftime('%Y%m%d','now')").get(uid);
  const search  = db.prepare("SELECT summary, start_dt FROM calendar_event_cache WHERE user_id=? AND LOWER(summary) LIKE '%arzt%'").all(uid);
  res.json({ count: count.n, today: today.d, future_count: future.n, samples, arzt_matches: search });
});


module.exports = router;