const Benchmark = require('benchmark')
const suite = new Benchmark.Suite()

const headers = ['application/json', 'application/json; charset=utf-8']

function getContentType (header) {
  if (!header) return ''
  return header.split(/[ ;]/, 1)[0].trim().toLowerCase()
}
function getContentTypeLoop (header) {
  if (!header) return ''

  // The Content-Type header field indicates the media type of the resource
  // The media type format is:
  // media-type = type "/" subtype parameters
  // type       = token
  // subtype    = token
  // The type/subtype MAY be followed by semicolon-delimited parameters
  // https://datatracker.ietf.org/doc/html/rfc9110#section-8.3.1

  // Tokens are case-insensitive and consist of:
  // https://datatracker.ietf.org/doc/html/rfc9110#name-tokens

  //   tchar          = "!" / "#" / "$" / "%" / "&" / "'" / "*"
  //                  / "+" / "-" / "." / "^" / "_" / "`" / "|" / "~"
  //                  / DIGIT / ALPHA
  //                  ; any VCHAR, except delimiters
  // Many HTTP field values are defined using common syntax components, separated by whitespace or specific delimiting characters.
  // Delimiters are chosen from the set of US-ASCII visual characters not allowed in a token (DQUOTE and "(),/:;<=>?@[\]{}").

  header = header.trim().toLowerCase()
  let firstToken = true
  for (let i = 0; i < header.length; i++) {
    const char = header.codePointAt(i)
    const isDelimiterChar = isDelimiter(char)
    if (!isDelimiterChar) {
      continue
    }

    if (firstToken) {
      if (char !== 47) {
        // The first delimiter MUST be a slash
        throw new Error('Invalid Content-Type header')
      } else {
        firstToken = false
      }
    } else { // Look for the second delimiter
      if (char !== 59 && char !== 32) {
        // The second delimiter MUST be a semicolon or a space
        throw new Error('Invalid Content-Type header')
      }
      return header.slice(0, i)
    }
  }

  // If we reach here, it means we didn't find a semicolon
  return header
}

function isDelimiter (charCode) {
  // Delimiters are defined by the RFC 9110: (DQUOTE and "(),/:;<=>?@[\]{}")
  return charCode <= 32 || // NOT any VCHAR (visible char): these must be not included in token
    charCode === 34 || // DQUOTE
    charCode === 40 || // (
    charCode === 41 || // )
    charCode === 44 || // ,
    charCode === 47 || // /
    charCode === 58 || // :
    charCode === 59 || // ;
    charCode === 60 || // <
    charCode === 61 || // =
    charCode === 62 || // >
    charCode === 63 || // ?
    charCode === 64 || // @
    charCode === 91 || // [
    charCode === 92 || // \
    charCode === 93 || // ]
    charCode === 123 || // {
    charCode === 125 // }
}

for (const h of headers) {
  suite.add(`getContentType [${h}]`, getContentType.bind(null, h))
  suite.add(`getContentTypeLoop [${h}]`, getContentTypeLoop.bind(null, h))
}

suite.on('cycle', function (event) {
  console.log(String(event.target))
})
  .on('complete', function () {
    console.log('Fastest is ' + this.filter('fastest').map('name'))
  })
  .run()