/**
 * IP2Location Service
 *
 * Uses local IP2Location LITE DB3 database for IP geolocation.
 * No external API calls, no rate limits.
 *
 * Database: IP2Location LITE DB3 (free, monthly updates)
 * Fields: country, region, city, latitude, longitude
 */

import path from 'path';
import fs from 'fs';

// @ts-ignore - no types for ip2location-nodejs
const { IP2Location } = require('ip2location-nodejs');

const DB_PATH = process.env.IP2LOCATION_DB_PATH ||
  path.join(__dirname, '../../data/ip2location/IP2LOCATION-LITE-DB5.BIN');

let ip2location: any = null;
let dbLoaded = false;

/**
 * Initialize IP2Location database
 */
export function initIP2Location(): boolean {
  if (dbLoaded) return true;

  try {
    if (!fs.existsSync(DB_PATH)) {
      console.warn(`IP2Location database not found at: ${DB_PATH}`);
      console.warn('Run: ./scripts/download-ip2location.sh to download');
      return false;
    }

    ip2location = new IP2Location();
    ip2location.open(DB_PATH);
    dbLoaded = true;
    console.log('IP2Location database loaded successfully');
    return true;
  } catch (err) {
    console.error('Failed to load IP2Location database:', err);
    return false;
  }
}

/**
 * Close IP2Location database
 */
export function closeIP2Location(): void {
  if (ip2location) {
    ip2location.close();
    ip2location = null;
    dbLoaded = false;
  }
}

export interface GeoLocation {
  city: string | null;
  state: string | null;
  stateCode: string | null;
  country: string | null;
  countryCode: string | null;
  lat: number | null;
  lng: number | null;
}

/**
 * Lookup IP address location
 *
 * @param ip - IPv4 or IPv6 address
 * @returns Location data or null if not found
 */
export function lookupIP(ip: string): GeoLocation | null {
  // Skip private/localhost IPs
  if (!ip || ip === '127.0.0.1' || ip === '::1' ||
      ip.startsWith('192.168.') || ip.startsWith('10.') ||
      ip.startsWith('172.16.') || ip.startsWith('172.17.') ||
      ip.startsWith('::ffff:127.') || ip.startsWith('::ffff:192.168.') ||
      ip.startsWith('::ffff:10.')) {
    return null;
  }

  // Strip IPv6 prefix if present
  const cleanIP = ip.replace(/^::ffff:/, '');

  // Initialize on first use if not already loaded
  if (!dbLoaded) {
    if (!initIP2Location()) {
      return null;
    }
  }

  try {
    const result = ip2location.getAll(cleanIP);

    if (!result || result.ip === '?' || result.countryShort === '-') {
      return null;
    }

    // DB3 LITE doesn't include lat/lng - would need DB5+ for that
    const lat = typeof result.latitude === 'number' && result.latitude !== 0 ? result.latitude : null;
    const lng = typeof result.longitude === 'number' && result.longitude !== 0 ? result.longitude : null;

    return {
      city: result.city !== '-' ? result.city : null,
      state: result.region !== '-' ? result.region : null,
      stateCode: null, // DB3 doesn't include state codes
      country: result.countryLong !== '-' ? result.countryLong : null,
      countryCode: result.countryShort !== '-' ? result.countryShort : null,
      lat,
      lng,
    };
  } catch (err) {
    console.error('IP2Location lookup error:', err);
    return null;
  }
}

/**
 * Check if IP2Location database is available
 */
export function isIP2LocationAvailable(): boolean {
  if (dbLoaded) return true;
  return fs.existsSync(DB_PATH);
}

// Export singleton-style interface
export default {
  init: initIP2Location,
  close: closeIP2Location,
  lookup: lookupIP,
  isAvailable: isIP2LocationAvailable,
};