// copied directly from https://github.com/bvaughn/react-virtualized/blob/master/playground/helper.js

function loadStyle (source, callback) {
  var link = document.createElement('link')
  link.setAttribute('rel', 'stylesheet')
  link.setAttribute('href', source)
  link.onload = callback
  document.head.appendChild(link)
}

function loadScript (source) {
  var script = document.createElement('script')
  script.setAttribute('src', source)
  script.async = false
  document.head.appendChild(script)
}

function loadScriptsAndStyles (source) {
  var baseDir = 'https://unpkg.com/react-virtualized/'
  var sourceParam = getUrlParam('source')

  if (sourceParam) {
    baseDir = sourceParam === 'local'
      ? '../'
      : `https://unpkg.com/react-virtualized@${sourceParam}/`
  }

  var styleSource = baseDir + 'styles.css'
  var scriptSource = baseDir + 'dist/umd/react-virtualized.js'
  var appSource = source

  loadStyle(styleSource, function() {
    loadScript(scriptSource)
    loadScript(appSource)
  })
}

function loadReact () {
  var baseDir = 'https://cdnjs.cloudflare.com/ajax/libs/react/15.2.0'
  var reactParam = getUrlParam('react')

  if (reactParam) {
    baseDir = reactParam === 'latest'
      ? 'http://react.zpao.com/builds/master/latest'
      : `https://cdnjs.cloudflare.com/ajax/libs/react/${reactParam}`
  }

  loadScript(`${baseDir}/react-with-addons.min.js`)
  loadScript(`${baseDir}/react-dom.min.js`)
}