import type { ParsedDanmu, ParserReply, ParserRequest } from './parser-types'

export function getMode(key: number): number {
  switch (key) {
    case 1:
    case 2:
    case 3:
      return 0
    case 4:
      return 2
    case 5:
      return 1
    default:
      return 0
  }
}

export function bilibiliDanmuParseFromXml(xmlString: unknown): ParsedDanmu[] {
  if (typeof xmlString !== 'string')
    return []
  const reg = /<d[^>]*?p="(?<p>[^"]+)"[^>]*>(?<text>.*?)<\/d>/gs
  const matches = xmlString.matchAll(reg)
  return Array.from(matches)
    .map((match) => {
      const attr = match.groups!.p!.split(',')
      if (attr.length >= 8) {
        const text = match.groups!.text!
          .trim()
          .replaceAll('&quot;', '"')
          .replaceAll('&apos;', '\'')
          .replaceAll('&lt;', '<')
          .replaceAll('&gt;', '>')
          .replaceAll('&amp;', '&')

        return {
          text,
          time: Number(attr[0]),
          mode: getMode(Number(attr[1])),
          fontSize: Number(attr[2]),
          color: `#${Number(attr[3]).toString(16)}`,
          timestamp: Number(attr[4]),
          pool: Number(attr[5]),
          userID: attr[6]!,
          rowID: Number(attr[7]),
        }
      }
      else {
        return null
      }
    })
    .filter(Boolean) as ParsedDanmu[]
}

export function onmessage({ data }: MessageEvent<ParserRequest>) {
  const { xml, id } = data
  const danmus = bilibiliDanmuParseFromXml(xml)
  globalThis.postMessage({ danmus, id } satisfies ParserReply)
}