'use strict';

const axios     = require('axios');
const UAParser  = require('ua-parser-js');

const LOCALHOST = new Set(['::1', '127.0.0.1', '::ffff:127.0.0.1']);

const getIP = (req) => {
  const forwarded = req.headers['x-forwarded-for'];
  if (forwarded) return forwarded.split(',')[0].trim();
  return req.ip || req.connection?.remoteAddress || null;
};

const parseUA = (uaString) => {
  const p = new UAParser(uaString || '');
  return {
    ua:      uaString || 'unknown',
    browser: [p.getBrowser().name, p.getBrowser().version].filter(Boolean).join(' ') || 'unknown',
    os:      [p.getOS().name, p.getOS().version].filter(Boolean).join(' ') || 'unknown',
    device:  p.getDevice().type || 'desktop',
  };
};

const getGeo = async (ip) => {
  if (!ip || LOCALHOST.has(ip)) return { country: null, region: null, city: null, lat: null, lon: null };

  try {
    const { data } = await axios.get(
      `http://ip-api.com/json/${ip}?fields=status,country,regionName,city,lat,lon`,
      { timeout: 3000 }
    );
    if (data.status !== 'success') return { country: null, region: null, city: null, lat: null, lon: null };
    return { country: data.country, region: data.regionName, city: data.city, lat: data.lat, lon: data.lon };
  } catch {
    return { country: null, region: null, city: null, lat: null, lon: null };
  }
};

/**
 * Builds a rich session info object from the request.
 * Used for both login_info and logout_info.
 *
 * @param {import('express').Request} req
 * @param {Object} extras  — e.g. { forced_by: admin_user_id }
 * @returns {Promise<Object>}
 */
const buildSessionInfo = async (req, extras = {}) => {
  const ip  = getIP(req);
  const geo = await getGeo(ip);

  return {
    date:        new Date().toISOString(),
    ip_address:  ip,
    country:     geo.country,
    region:      geo.region,
    city:        geo.city,
    lat:         geo.lat,
    lon:         geo.lon,
    device_info: parseUA(req.headers['user-agent']),
    ...extras,
  };
};

module.exports = buildSessionInfo;
module.exports.parseUA = parseUA;
module.exports.getIP = getIP;