MusicServer/sdk/kw/util.ts

import { handleKwDecodeLyric } from './lyricDecode.ts'
import { createCipheriv, createDecipheriv } from 'crypto'
import { toMD5 } from '../utils.ts'


export const objStr2JSON = (str: string): any => {
  return JSON.parse(str.replace(/('(?=(,\s*')))|('(?=:))|((?<=([:,]\s*))')|((?<={)')|('(?=}))/g, '"'))
}


export const formatSinger = (rawData: string): string => rawData.replace(/&/g, '、')

export const matchToken = (headers: Record<string, any>): string | null => {
  try {
    return headers['set-cookie'][0].match(/kw_token=(\w+)/)[1]
  } catch (err) {
    return null
  }
}


export const decodeLyric = handleKwDecodeLyric


interface LrcWordInfo {
  startTime: number
  endTime: number
  timeStr: string
  newTimeStr?: string
}

export const lrcTools = {
  rxps: {
    wordLine: /^(\[\d{1,2}:.*\d{1,4}\])\s*(\S+(?:\s+\S+)*)?\s*/,
    tagLine: /\[(ver|ti|ar|al|offset|by|kuwo):\s*(\S+(?:\s+\S+)*)\s*\]/,
    wordTimeAll: /<(-?\d+),(-?\d+)(?:,-?\d+)?>/g,
    wordTime: /<(-?\d+),(-?\d+)(?:,-?\d+)?>/,
  },
  offset: 1,
  offset2: 1,
  isOK: false,
  lines: [] as string[],
  tags: [] as string[],
  getWordInfo(str: string, str2: string, prevWord?: LrcWordInfo): LrcWordInfo {
    const offset = parseInt(str)
    const offset2 = parseInt(str2)
    let startTime = Math.abs((offset + offset2) / (this.offset * 2))
    let endTime = Math.abs((offset - offset2) / (this.offset2 * 2)) + startTime
    if (prevWord) {
      if (startTime < prevWord.endTime) {
        prevWord.endTime = startTime
        if (prevWord.startTime > prevWord.endTime) {
          prevWord.startTime = prevWord.endTime
        }

        prevWord.newTimeStr = `<${prevWord.startTime},${prevWord.endTime - prevWord.startTime}>`
      }
    }
    return {
      startTime,
      endTime,
      timeStr: `<${startTime},${endTime - startTime}>`,
    }
  },
  parseLine(line: string): void {
    if (line.length < 6) return
    let result = this.rxps.wordLine.exec(line)
    if (result) {
      const time = result[1]
      let words = result[2]
      if (words == null) {
        words = ''
      }
      const wordTimes = words.match(this.rxps.wordTimeAll)
      if (!wordTimes) return
      let preTimeInfo
      for (const timeStr of wordTimes) {
        const result = this.rxps.wordTime.exec(timeStr)
        const wordInfo = this.getWordInfo(result![1], result![2], preTimeInfo)
        words = words.replace(timeStr, wordInfo.timeStr)
        if (preTimeInfo?.newTimeStr) words = words.replace(preTimeInfo.timeStr, preTimeInfo.newTimeStr)
        preTimeInfo = wordInfo
      }
      this.lines.push(time + words)
      return
    }
    result = this.rxps.tagLine.exec(line)
    if (!result) return
    if (result[1] == 'kuwo') {
      let content = result[2]
      if (content != null && content.includes('][')) {
        content = content.substring(0, content.indexOf(']['))
      }
      const valueOf = parseInt(content, 8)
      this.offset = Math.trunc(valueOf / 10)
      this.offset2 = Math.trunc(valueOf % 10)
      if (this.offset == 0 || Number.isNaN(this.offset) || this.offset2 == 0 || Number.isNaN(this.offset2)) {
        this.isOK = false
      }
    } else {
      this.tags.push(line)
    }
  },
  parse(lrc: string): string {
    const lines = lrc.split(/\r\n|\r|\n/)
    const tools = Object.create(this)
    tools.isOK = true
    tools.offset = 1
    tools.offset2 = 1
    tools.lines = []
    tools.tags = []

    for (const line of lines) {
      if (!tools.isOK) throw new Error('failed')
      tools.parseLine(line)
    }
    if (!tools.lines.length) return ''
    let lrcs = tools.lines.join('\n')
    if (tools.tags.length) lrcs = `${tools.tags.join('\n')}\n${lrcs}`
    return lrcs
  },
}


const createAesEncrypt = (buffer: Buffer, mode: string, key: Buffer | string, iv: string | Buffer): Buffer => {
  const cipher = createCipheriv(mode, key, iv)
  return Buffer.concat([cipher.update(buffer), cipher.final()])
}

const createAesDecrypt = (buffer: Buffer, mode: string, key: Buffer | string, iv: string | Buffer): Buffer => {
  const cipher = createDecipheriv(mode, key, iv)
  return Buffer.concat([cipher.update(buffer), cipher.final()])
}

export const wbdCrypto = {
  aesMode: 'aes-128-ecb',
  aesKey: Buffer.from([112, 87, 39, 61, 199, 250, 41, 191, 57, 68, 45, 114, 221, 94, 140, 228] as any, 'binary'),
  aesIv: '',
  appId: 'y67sprxhhpws',
  decodeData(base64Result: string): any {
    const data = Buffer.from(decodeURIComponent(base64Result), 'base64')
    return JSON.parse(createAesDecrypt(data, this.aesMode, this.aesKey, this.aesIv).toString())
  },
  createSign(data: string, time: number): string {
    const str = `${this.appId}${data}${time}`
    return toMD5(str).toUpperCase()
  },
  buildParam(jsonData: unknown): string {
    const data = Buffer.from(JSON.stringify(jsonData))
    const time = Date.now()

    const encodeData = createAesEncrypt(data, this.aesMode, this.aesKey, this.aesIv).toString('base64')
    const sign = this.createSign(encodeData, time)

    return `data=${encodeURIComponent(encodeData)}&time=${time}&appId=${this.appId}&sign=${sign}`
  },
}