const { google } = require('googleapis');
const fs = require('fs');
const readline = require('readline');

const SCOPES = ['https://www.googleapis.com/auth/youtube.force-ssl'];
const TOKEN_PATH = 'token.json';
const CREDENTIALS_PATH = 'client_secrets.json';

function authenticate() {
  const credentials = JSON.parse(fs.readFileSync(CREDENTIALS_PATH));
  const { client_secret, client_id, redirect_uris } = credentials.installed;
  const oAuth2Client = new google.auth.OAuth2(
    client_id,
    client_secret,
    redirect_uris[0]
  );

  // Check if we have previously stored a token.
  if (fs.existsSync(TOKEN_PATH)) {
    const token = fs.readFileSync(TOKEN_PATH);
    oAuth2Client.setCredentials(JSON.parse(token));
    return oAuth2Client;
  } else {
    return getNewToken(oAuth2Client);
  }
}

function getNewToken(oAuth2Client) {
  const authUrl = oAuth2Client.generateAuthUrl({
    access_type: 'offline',
    scope: SCOPES,
  });

  const rl = readline.createInterface({
    input: process.stdin,
    output: process.stdout,
  });

  console.log('Authorize this app by visiting this url:', authUrl);

  return new Promise((resolve, reject) => {
    rl.question('Enter the code from that page here: ', (code) => {
      rl.close();
      oAuth2Client.getToken(code, (err, token) => {
        if (err) {
          reject(err);
        } else {
          oAuth2Client.setCredentials(token);
          fs.writeFileSync(TOKEN_PATH, JSON.stringify(token));
          resolve(oAuth2Client);
        }
      });
    });
  });
}

async function getVideoId() {
  const videoUrl = await new Promise((resolve, reject) => {
    const rl = readline.createInterface({
      input: process.stdin,
      output: process.stdout,
    });
    rl.question('Enter YouTube video URL: ', (url) => {
      rl.close();
      resolve(url);
    });
  });
  const url = new URL(videoUrl);
  return url.searchParams.get('v');
}

async function getVideoViews(videoId) {
  const auth = await authenticate();
  const youtube = google.youtube({ version: 'v3', auth });
  const response = await youtube.videos.list({
    part: 'statistics',
    id: videoId,
  });
  const views = response.data.items[0].statistics.viewCount;
  return views;
}

async function updateVideoTitle(videoId, views) {
  const auth = await authenticate();
  const youtube = google.youtube({ version: 'v3', auth });
  const response = await youtube.videos.update({
    part: 'snippet',
    requestBody: {
      id: videoId,
      snippet: { title: views + ' просмотров' },
    },
  });
  console.log('Video title successfully updated!');
}

async function main() {
  const videoId = await getVideoId();
  const views = await getVideoViews(videoId);
  await updateVideoTitle(videoId, views);
}

main().catch(console.error);