// Database pool setup and lifecycle maintenance for persisted onboarding devices.

const mysql = require('mysql2/promise');

function createPool() {
  return mysql.createPool({
    host: process.env.DB_HOST || '127.0.0.1',
    port: Number(process.env.DB_PORT || 3306),
    user: process.env.DB_USER || 'signage_user',
    password: process.env.DB_PASSWORD || 'signage_password',
    database: process.env.DB_NAME || 'signage',
    timezone: 'Z',
    waitForConnections: true,
    connectionLimit: 10,
    namedPlaceholders: true
  });
}

async function pruneStaleOnboardingDevices(pool) {
  // Uncompleted pairings expire quickly; completed bindings use their persisted heartbeat instead.
  await pool.query(
    `DELETE FROM d_onboarding_devices
     WHERE (screen_id IS NULL
           AND modified_at < (CURRENT_TIMESTAMP - INTERVAL 15 MINUTE))
        OR (last_seen_at IS NOT NULL
            AND last_seen_at < (CURRENT_TIMESTAMP - INTERVAL 24 HOUR))`
  );
}

async function touchOnboardingDeviceLastSeen(pool, deviceId) {
  const deviceIds = (Array.isArray(deviceId) ? deviceId : [deviceId])
    .map(function (value) { return String(value || '').trim(); })
    .filter(Boolean);
  if (!deviceIds.length) {
    return;
  }

  await pool.query(
    `UPDATE d_onboarding_devices
        SET last_seen_at = CURRENT_TIMESTAMP
      WHERE device_id IN (${deviceIds.map(function () { return '?'; }).join(', ')})`,
    deviceIds
  );
}

module.exports = {
  createPool,
  pruneStaleOnboardingDevices,
  touchOnboardingDeviceLastSeen
};