'use strict'

const continents = require('./continents.json')
const countries = require('./countries.emoji.json')
const languages = require('./languages.json')
const languagesAll = require('./languages.all.json')

// See: https://github.com/bestiejs/punycode.js#installation
const {
  ucs2: { decode, encode },
} = require('punycode/punycode')

const // "Regional Indicator Symbol Letter A" - "Latin Capital Letter A"
  UNICODE_BASE = 127462 - 'A'.charCodeAt(0),
  // Country code should contain exactly 2 uppercase characters from A..Z
  COUNTRY_CODE_REGEX = /^[A-Z]{2}$/

const getEmojiFlag = (countryCode) => {
  if (!COUNTRY_CODE_REGEX.test(countryCode)) {
    return ''
  }

  return encode(countryCode.split('').map((letter) => UNICODE_BASE + letter.charCodeAt(0)))
}

const getUnicode = (emoji) => {
  return decode(emoji)
    .map((code) => 'U+' + Number(code).toString(16).toUpperCase())
    .join(' ')
}

module.exports = {
  continents,
  countries,
  languages,
  languagesAll,

  getEmojiFlag,
  getUnicode,
}