// @flow
import type { EmotionCache } from '@emotion/utils'
import through from 'through'
import tokenize from 'html-tokenize'
import pipe from 'multipipe'

const createRenderStylesToNodeStream =
  (cache: EmotionCache, nonceString: string) => () => {
    let insed = {}
    const tokenStream = tokenize()

    const inlineStream = through(
      function write(thing) {
        let [type, data] = thing
        if (type === 'open') {
          let css = ''
          let ids = {}

          let match
          let fragment = data.toString()
          let regex = new RegExp(`${cache.key}-([a-zA-Z0-9-_]+)`, 'gm')
          while ((match = regex.exec(fragment)) !== null) {
            if (match !== null && insed[match[1]] === undefined) {
              ids[match[1]] = true
            }
          }
          Object.keys(cache.inserted).forEach(id => {
            if (
              cache.inserted[id] !== true &&
              insed[id] === undefined &&
              (ids[id] === true ||
                (cache.registered[`${cache.key}-${id}`] === undefined &&
                  (ids[id] = true)))
            ) {
              insed[id] = true
              // $FlowFixMe flow thinks emotion.caches.inserted[id] can be true even though it's checked earlier
              css += cache.inserted[id]
            }
          })

          if (css !== '') {
            this.queue(
              `<style data-emotion="${cache.key} ${Object.keys(ids).join(
                ' '
              )}"${nonceString}>${css}</style>`
            )
          }
        }
        this.queue(data)
      },
      function end() {
        this.queue(null)
      }
    )

    return pipe(tokenStream, inlineStream)
  }

export default createRenderStylesToNodeStream