const { promisify } = require('util')
const dns = require('dns')
const lookup = promisify(dns.lookup)
const request = require('request')

const { DEV, SERVER_IP } = require('../config')

// https://www.torproject.org/projects/tordnsel.html.en
// check if request comes from tor
const fromTor = async (req, res, next) => {
  if (DEV) {
    req.fromTor = req.query.fromTor || false
    return next()
  }
  const sourceIp = req.headers['x-forwarded-for'] || req.connection.remoteAddress
  const ip = sourceIp.split('.').reverse().join('.')
  const reversedServerIp = SERVER_IP.split('.').reverse().join('.')
  const domain = `${ip}.80.${reversedServerIp}.ip-port.exitlist.torproject.org`
  try {
    const ret = await lookup(domain, {})
    req.fromTor = (ret.address === '127.0.0.2')
  } catch(e) {
    req.fromTor = false
  }
  next()
}

// check if request comes from proxy/VPN/tor
const fromVpn = async (req, res, next) => {
  if (DEV) {
    req.fromVpn = req.query.fromVpn || false
    return next()
  }
  const sourceIp = req.headers['x-forwarded-for'] || req.connection.remoteAddress
  const baseUrl = 'https://check.getipintel.net/check.php?ip='
  const url = `${baseUrl}${sourceIp}&contact=anna@fugadalcontrollo.org`
  request(url, 
    (err, res, body) => {
      if (!err && res.statusCode === 200) {
        req.fromVpn = parseFloat(body)>0.5
      } else {
        req.fromVpn = false
      }
      next()
    })
}

const checkCountry = (req, res, next) => {
  if (DEV) {
    return next()
  }
  const sourceIp = req.headers['x-forwarded-for'] || req.connection.remoteAddress
  request(`http://ip-api.com/json/${sourceIp}`, (err, res, body) => {
    if (!err && res.statusCode === 200) {
      try {
        req.geoinfo = JSON.parse(body)
      } catch (e) {}
    }
    next()
  })
}

module.exports = { fromTor, fromVpn, checkCountry }