module.exports = function utf8_decode(strData) {
  //  discuss at: https://locutus.io/php/utf8_decode/
  // original by: Webtoolkit.info (https://www.webtoolkit.info/)
  //    input by: Aman Gupta
  //    input by: Brett Zamir (https://brett-zamir.me)
  // improved by: Kevin van Zonneveld (https://kvz.io)
  // improved by: Norman "zEh" Fuchs
  // bugfixed by: hitwork
  // bugfixed by: Onno Marsman (https://twitter.com/onnomarsman)
  // bugfixed by: Kevin van Zonneveld (https://kvz.io)
  // bugfixed by: kirilloid
  // bugfixed by: w35l3y (https://www.wesley.eti.br)
  //   example 1: utf8_decode('Kevin van Zonneveld')
  //   returns 1: 'Kevin van Zonneveld'

  const tmpArr = []
  let i = 0
  let c1 = 0
  let seqlen = 0

  strData += ''

  while (i < strData.length) {
    c1 = strData.charCodeAt(i) & 0xff
    seqlen = 0

    // https://en.wikipedia.org/wiki/UTF-8#Codepage_layout
    if (c1 <= 0xbf) {
      c1 = c1 & 0x7f
      seqlen = 1
    } else if (c1 <= 0xdf) {
      c1 = c1 & 0x1f
      seqlen = 2
    } else if (c1 <= 0xef) {
      c1 = c1 & 0x0f
      seqlen = 3
    } else {
      c1 = c1 & 0x07
      seqlen = 4
    }

    for (let ai = 1; ai < seqlen; ++ai) {
      c1 = (c1 << 0x06) | (strData.charCodeAt(ai + i) & 0x3f)
    }

    if (seqlen === 4) {
      c1 -= 0x10000
      tmpArr.push(String.fromCharCode(0xd800 | ((c1 >> 10) & 0x3ff)))
      tmpArr.push(String.fromCharCode(0xdc00 | (c1 & 0x3ff)))
    } else {
      tmpArr.push(String.fromCharCode(c1))
    }

    i += seqlen
  }

  return tmpArr.join('')
}