import * as uuidv4 from 'uuid/v4'
import * as crypto from 'crypto-browserify'

export const VISITOR_ID = 'vstr_id'
export const DEVICE_ID = 'tracker_device_id'
export const SESSION_STAMP = 'tracker_session_stamp'

import { addMonthToDate } from './helpers'

export const generateValueFor = name => {
  switch (name) {
    case VISITOR_ID:
      return crypto.randomBytes(16).toString('base64')

    case SESSION_STAMP:
      return Number(new Date().getTime())

    case DEVICE_ID:
      return `w_${uuidv4()}`

    default:
      return uuidv4()
  }
}

export const getExpirationFor = name => {
  switch (name) {
    case VISITOR_ID:
      return addMonthToDate(13)

    case DEVICE_ID:
      return addMonthToDate(1)

    default:
      return null
  }
}

/**
 * Split hostname to get domain, subdomain, and extension
 * @param {String} hostname
 * @return {Object}
 */
const splitHostname = hostname => {
  if (!hostname.includes('.')) {
    return { domain: hostname }
  }

  const regexParse = new RegExp('([a-z-0-9]{2,63}).([a-z.]{2,6})$')
  const [, domain, extension] = regexParse.exec(hostname)

  return {
    domain,
    extension,
    subdomain: hostname.replace(`${domain}.${extension}`, '').slice(0, -1),
  }
}

/**
 * Test hostname to know if it's an IP address
 * @param {String} hostname
 * @return {Boolean}
 */
const isIpAddress = (hostname: string): boolean => {
  const regexIpAddress = new RegExp(
    '^(([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5]).){3}([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])$',
  )
  return regexIpAddress.test(hostname)
}

/**
 * Test hostname to know if it's a private IP address
 * @see https://stackoverflow.com/questions/2814002/private-ip-address-identifier-in-regular-expression
 * @param {String} hostname
 * @return {Boolean}
 */
const isPrivateIpAddress = (hostname: string): boolean => {
  const privateIpRegexp = new RegExp('(^127\.)|(^10\.)|(^172\.1[6-9]\.)|(^172\.2[0-9]\.)|(^172\.3[0-1]\.)|(^192\.168\.)')
  return isIpAddress(hostname) && privateIpRegexp.test(hostname)
}

export const getCookieDomain = hostname => {
  if (hostname === 'localhost' || hostname === '127.0.0.1' || isPrivateIpAddress(hostname)) {
    return 'localhost'
  }

  const { domain, extension } = splitHostname(hostname)
  if (extension) {
    return `.${domain}.${extension}`
  }
  return domain
}