"use strict"

const anyDataURLRegexp = /^data:text\/css(?:;(base64|plain))?,/i
const base64DataURLRegexp = /^data:text\/css;base64,/i
const plainDataURLRegexp = /^data:text\/css;plain,/i

function isValid(url) {
  return anyDataURLRegexp.test(url)
}

function contents(url) {
  if (base64DataURLRegexp.test(url)) {
    // "data:text/css;base64,".length === 21
    return Buffer.from(url.slice(21), "base64").toString()
  }

  if (plainDataURLRegexp.test(url)) {
    // "data:text/css;plain,".length === 20
    return decodeURIComponent(url.slice(20))
  }

  // "data:text/css,".length === 14
  return decodeURIComponent(url.slice(14))
}

module.exports = {
  isValid,
  contents,
}