const { RIR_DELEGATION_URLS } = require("./data/rir-delegation-urls");

// FEATURE 4: IPv6 Adoption per RIR

// In-memory cache: { data, ts }
let ipv6StatsCache = null;
const IPV6_STATS_TTL = 24 * 60 * 60 * 1000; // 24h

// Fetch and parse one RIR delegation file.
// Returns { ipv4, ipv6, asns } count objects.
function fetchRirDelegation(rir, url) {
  return new Promise((resolve) => {
    const result = { rir, ipv4: 0, ipv6: 0, asns: 0, ipv4_countries: new Set(), ipv6_countries: new Set() };
    const mod = url.startsWith('https') ? require('https') : require('http');
    const req = mod.get(url, { headers: { 'User-Agent': 'PeerCortex/1.0 (+https://peercortex.org)' }, timeout: 20000 }, res => {
      if (res.statusCode !== 200) { resolve(result); return; }
      let buf = '';
      res.on('data', d => { buf += d; });
      res.on('end', () => {
        for (const line of buf.split('\n')) {
          if (line.startsWith('#') || line.startsWith(rir.toLowerCase() + '|*') || !line.includes('|')) continue;
          const parts = line.split('|');
          if (parts.length < 7) continue;
          const type   = parts[2];
          const status = parts[6].trim();
          const cc     = parts[1];
          if (status !== 'allocated' && status !== 'assigned') continue;
          if (type === 'ipv4') { result.ipv4++; result.ipv4_countries.add(cc); }
          else if (type === 'ipv6') { result.ipv6++; result.ipv6_countries.add(cc); }
          else if (type === 'asn') { result.asns++; }
        }
        resolve(result);
      });
    });
    req.on('error', () => resolve(result));
    req.on('timeout', () => { req.destroy(); resolve(result); });
  });
}

// Fetch all 5 RIR delegation files and aggregate IPv6 stats.
// Cached for 24 hours.
async function fetchIpv6AdoptionStats(force) {
  if (!force && ipv6StatsCache && (Date.now() - ipv6StatsCache.ts) < IPV6_STATS_TTL) {
    return ipv6StatsCache.data;
  }
  console.log('[IPv6] Fetching RIR delegation stats...');
  const results = await Promise.all(
    Object.entries(RIR_DELEGATION_URLS).map(([rir, url]) => fetchRirDelegation(rir, url))
  );
  const rirs = results.map(r => ({
    rir: r.rir,
    ipv4_records: r.ipv4,
    ipv6_records: r.ipv6,
    asn_records:  r.asns,
    ipv6_pct:     (r.ipv4 + r.ipv6) > 0
      ? Math.round((r.ipv6 / (r.ipv4 + r.ipv6)) * 10000) / 100
      : 0,
    countries_with_ipv6: r.ipv6_countries.size,
    countries_with_ipv4: r.ipv4_countries.size,
  }));
  const total_ipv4 = rirs.reduce((s, r) => s + r.ipv4_records, 0);
  const total_ipv6 = rirs.reduce((s, r) => s + r.ipv6_records, 0);
  const data = {
    fetched_at: new Date().toISOString(),
    global_ipv6_pct: total_ipv4 + total_ipv6 > 0
      ? Math.round((total_ipv6 / (total_ipv4 + total_ipv6)) * 10000) / 100
      : 0,
    total_ipv4_records: total_ipv4,
    total_ipv6_records: total_ipv6,
    by_rir: rirs,
  };
  ipv6StatsCache = { data, ts: Date.now() };
  console.log(`[IPv6] Done. Global IPv6%: ${data.global_ipv6_pct}% across ${rirs.length} RIRs`);
  return data;
}

// Pre-fetch on startup (non-blocking)
fetchIpv6AdoptionStats().catch(() => {});

module.exports = { fetchRirDelegation, fetchIpv6AdoptionStats };