/**
 * TikTok Event Logger
 * This file fetches the frida event and eventv3 logs and outputs each event as JSON + \n to ./output.txt
 * It hookes com.ss.android.common.applog.g.insertEvent and sends it to the onMessage listener which does the actual I/O
 *
 * Prerequisites:
 * Have frida-server installed
 * Make sure you've run have setenforce 0 via adb shell
 * Run frida -U -n com.zhiliaoapp.musically -l ./index.js
 *
 */
'use strict'

const fs = require('fs')
const frida = require('frida')

const current = {
  device: null,
  pid: null,
  script: null
};

async function main() {
  process.on('SIGTERM', stop);
  process.on('SIGINT', stop);

  const device = await frida.getUsbDevice();
  current.device = device;
  device.output.connect(onOutput);
  console.log(device)

  const application = await device.getFrontmostApplication();
  console.log('[*] Frontmost application:', application);
  console.log('[*] spawn()');
  const pid = application.pid
  if (application.identifier !== 'com.zhiliaoapp.musically') {
    console.error('TikTok isnt the active app. Ending.')
    stop()
  }
  // let pid = 'com.zhiliaoapp.musically' // await device.spawn(['com.zhiliaoapp.musically'])
  console.log('PID is: ', pid)
  current.pid = pid;

  console.log(`[*] attach(${pid})`);
  const session = await device.attach(pid);
  session.detached.connect(onDetached);

  console.log(`[*] createScript()`);
  const script = await session.createScript(`
  if (Java.available) {
    Java.perform(function () {
        var EventLogger = Java.use('com.ss.android.common.applog.g');
        EventLogger.insertEvent.implementation = function (m) {
          var event = {
            category: m.category.value,
            ext_json: m.ext_json.value,
            ext_value: m.ext_value.value,
            id: m.id.value,
            instant_only: m.instant_only.value,
            label: m.label.value,
            mHasTimelySend: m.mHasTimelySend.value,
            session_id: m.session_id.value,
            tag: m.tag.value,
            teaEventIndex: m.teaEventIndex.value,
            timestamp: m.timestamp.value,
            user_id: m.user_id.value,
            value: m.value.value,
          }
          send(event)
          return this.insertEvent(m)
        }
    })
  }
`);
  current.script = script;
  script.message.connect(onMessage);
  await script.load();

}

function stop() {
  const { device, script } = current;

  if (script !== null) {
    script.unload();
    current.script = null;
  }

  if (device !== null) {
    device.output.disconnect(onOutput);
    current.device = null;
  }
}

function onOutput(pid, fd, data) {
  if (pid !== current.pid)
    return;

  let description;
  if (data.length > 0)
    description = '"' + data.toString().replace(/\n/g, '\\n') + '"';
  else
    description = '<EOF>';
  console.log(`[*] onOutput(pid=${pid}, fd=${fd}, data=${description})`);
}

function onDetached(reason) {
  console.log(`[*] onDetached(reason='${reason}')`);
  current.device.output.disconnect(onOutput);
}

function onMessage(message, data) {
  console.log('[*] onMessage() message:', message, 'data:', data);
  fs.appendFileSync('output-fresh.txt', `\n${JSON.stringify(message.payload)}`, 'utf8')
}

main()
  .catch(e => {
    console.error(e);
  });