const CDP = require('chrome-remote-interface');
const findProcess = require('find-process');

const processCmdRegex = /Slack\.app\/Contents\/MacOS\/Slack( .*)?$/;
const browserViewJs = `
  alert('hi');
`;
const mainProcessJs = `(() => {
  // Although require() is not exposed in global scope, you can find some interesting modules
  // by traversing from process.mainModule
  function findModule(rootModule, pattern) {
    let queue = [rootModule];
    const visited = new WeakSet(queue);

    while (queue.length > 0) {
      const module = queue.shift();
      if (module.filename && module.filename.match(pattern)) {
        return module;
      }

      if (module.children) {
        const uniqueChildren = module.children.filter(child => !visited.has(child));
        uniqueChildren.forEach(child => visited.add(child));
        queue = queue.concat(uniqueChildren);
      }
    }

    return null;
  }
  function req(pattern) {
    const root = global.process.mainModule;
    const module = findModule(root, pattern);
    return module && module.exports;
  }

  /////////////////////////

  const electron = req(/electron\.js$/);
  const BrowserView = electron.BrowserView;

  // We don't know what the id of the browserview will be, but it's usually small.
  // For the sake of this demo just take the first one we find.
  let bv = null;
  for (let i = 1; i < 10; i++) {
    try {
      bv = BrowserView.fromId(i);
      if (bv) {
        break;
      }
    } catch (err) {}
  }

  // Execute JS in the browserview
  const browserViewJs = ${JSON.stringify(browserViewJs)};
  bv.webContents.executeJavaScript(browserViewJs);

  bv.webContents.openDevTools();

  console.log('hi');
  global.xxx = true;
})();`;
const defaultPort = 9229;

async function main() {
  // Find process
  const processes = await findProcess('name', '');
  const proc = processes.filter(p => p.cmd.match(processCmdRegex))[0];
  if (!proc) {
    throw new Error('cant find process');
  }
  const pid = proc.pid;
  console.log('found process', pid, proc.cmd);

  // Enable debugger
  process.kill(pid, 'SIGUSR1');

  // Connect debugger
  const client = await CDP({port: defaultPort, host: 'localhost'});

  // Inject code
  const result = await client.Runtime.evaluate({expression: mainProcessJs});
}

main().then(() => process.exit(0));