// proxy/dataRetention.js
// ─────────────────────────────────────────────────────────────────────────────
// Pruning process for BackOne MongoDB data retention.
// Removes telemetry records older than 30 days to conserve database space.
// Also removes device/flow records that are outside the agent's configured subnet.
// ─────────────────────────────────────────────────────────────────────────────

const mongoose = require('mongoose');
const Schemas = require('./models/Schemas');

/**
 * Prune all time-series documents older than 30 days.
 */
async function pruneOldData() {
  const thirtyDaysAgo = new Date(Date.now() - 30 * 24 * 60 * 60 * 1000);
  const timeString = thirtyDaysAgo.toLocaleString('id-ID', { timeZone: 'Asia/Jakarta' }) + ' WIB';
  console.log(`[Collector] [Retention] Checking for telemetry data older than 30 days (before ${timeString})...`);

  // Prune from all collections in Schemas except CustomDeviceLabel
  const collections = Object.keys(Schemas).filter(name => name !== 'CustomDeviceLabel');

  for (const name of collections) {
    try {
      const Model = Schemas[name];
      if (typeof Model.deleteMany === 'function') {
        const res = await Model.deleteMany({ timestamp: { $lt: thirtyDaysAgo } });
        if (res.deletedCount > 0) {
          console.log(`[Collector] [Retention]   ✓ Cleaned up ${res.deletedCount} old records from ${name}`);
        }
      }
    } catch (err) {
      console.error(`[Collector] [Retention]   ✗ Failed to prune ${name}: ${err.message}`);
    }
  }

  // Also prune out-of-subnet data
  await pruneOutOfSubnetData();
}

// ─────────────────────────────────────────────────────────────────────────────
// Subnet-based cleanup: remove devices/flows that are outside the agent's
// configured allowed_subnets. Runs after every collection cycle automatically.
// ─────────────────────────────────────────────────────────────────────────────

function _ipToLong(ip) {
  return ip.split('.').reduce((acc, o) => (acc << 8) + parseInt(o, 10), 0) >>> 0;
}

function _ipMatchesSubnets(ip, subnets) {
  if (!ip || ip.includes(':')) return false; // skip IPv6
  if (!subnets || subnets.length === 0) return true; // no restriction
  return subnets.some(s => {
    if (s.includes('/')) {
      try {
        const [r, b] = s.split('/');
        const bits = parseInt(b, 10);
        if (isNaN(bits) || bits < 0 || bits > 32) return false;
        const mask = bits === 0 ? 0 : (~0 << (32 - bits)) >>> 0;
        return (_ipToLong(ip) & mask) === (_ipToLong(r) & mask);
      } catch { return false; }
    }
    return ip.startsWith(s + '.') || ip === s;
  });
}

async function pruneOutOfSubnetData() {
  try {
    const db = mongoose.connection.db;
    const agents = await db.collection('agent_registry')
      .find({ allowed_subnets: { $exists: true, $not: { $size: 0 } } })
      .toArray();

    for (const agent of agents) {
      const uuid = agent.uuid;
      const subnets = (agent.allowed_subnets || []).map(s => s.trim()).filter(Boolean);
      if (subnets.length === 0) continue;

      // devicestats
      const devIps = await db.collection('devicestats').distinct('ip_address', { agent_uuid: uuid });
      const badDevIps = devIps.filter(ip => !_ipMatchesSubnets(ip, subnets));
      if (badDevIps.length > 0) {
        const r1 = await db.collection('devicestats').deleteMany({ agent_uuid: uuid, ip_address: { $in: badDevIps } });
        const r2 = await db.collection('deviceappstats').deleteMany({ agent_uuid: uuid, ip_address: { $in: badDevIps } });
        if (r1.deletedCount + r2.deletedCount > 0) {
          console.log(`[Collector] [Subnet] ${uuid}: removed ${r1.deletedCount} device + ${r2.deletedCount} deviceapp records (${badDevIps.length} bad IPs)`);
        }
      }

      // flows
      const flowIps = await db.collection('flows').distinct('src_ip', { agent_uuid: uuid });
      const badFlowIps = flowIps.filter(ip => !_ipMatchesSubnets(ip, subnets));
      if (badFlowIps.length > 0) {
        const r = await db.collection('flows').deleteMany({ agent_uuid: uuid, src_ip: { $in: badFlowIps } });
        if (r.deletedCount > 0) {
          console.log(`[Collector] [Subnet] ${uuid}: removed ${r.deletedCount} flow records (${badFlowIps.length} bad IPs)`);
        }
      }
    }
  } catch (err) {
    console.error('[Collector] [Subnet] pruneOutOfSubnetData error:', err.message);
  }
}

module.exports = { pruneOldData, pruneOutOfSubnetData };