const flat = arr => [].concat.apply([], arr.map(a => Array.isArray(a) ? flat(a) : a));
// Or
const flat = arr => arr.reduce((a, b) => Array.isArray(b) ? [...a, ...flat(b)] : [...a, b], []);

// Or
// See the browser compatibility at https://caniuse.com/#feat=array-flat
const flat = arr => arr.flat();

// Example
flat(['cat', ['lion', 'tiger']]);   // ['cat', 'lion', 'tiger']

router.post("/", async (req, res) => {
	const { email, password } = req.body;

	try {
	if (!email) return res.status(400).json({ msg: "An email is required" });

	if (!password)
	return res.status(400).json({ msg: "A password is required" });

	const user = await User.findOne({ email }).select("_id password");

	if (!user) return res.status(400).json({ msg: "Invalid credentials" });

	const match = await bcrypt.compare(password, user.password);

	if (!match) return res.status(400).json({ msg: "Invalid credentials" });

	const accessToken = genAccessToken({ id: user._id });
	const refreshToken = genRefreshToken({ id: user._id });

	res.cookie("token", refreshToken, {
	expires: new Date(Date.now() + 604800),
	httpOnly: true,
	});

	res.json({ accessToken });
	} catch (err) {
	console.log(err.message);
	res.status(500).json({ msg: "Error logging in user" });
	}
});

var invertTree = function(root) {
    const reverseNode = node => {
        if (node == null) {
            return null
        }
        reverseNode(node.left);
        reverseNode(node.right);
        let holdLeft = node.left;
        node.left = node.right;
        node.right = holdLeft;
        return node;
    }

    return reverseNode(root);
};

const Discord = require('discord.js');
const client = new Discord.Client();
const token = 'YOUR_BOT_TOKEN';

// When the bot is ready, log a message to the console
client.on('ready', () => {
  console.log(`Logged in as ${client.user.tag}!`);
});

// When a user sends a message, check if they are authenticated
client.on('message', async (msg) => {
  if (!msg.author.bot && !msg.author.authenticated) {
    const filter = (m) => m.author.id === msg.author.id;
    const collector = msg.channel.createMessageCollector(filter, { time: 15000 });

    // Send an authentication message to the user
    msg.author.send('Please authenticate yourself by clicking this link: ' + generateAuthURL(msg.author.id));

    collector.on('collect', async (m) => {
      // Check if the message contains the authentication code
      if (m.content.startsWith('!auth ')) {
        const code = m.content.slice(6);
        const { access_token } = await getAccessToken(code);

        // Set the user's authenticated status and access token
        msg.author.authenticated = true;
        msg.author.access_token = access_token;
        collector.stop();
      }
    });

    collector.on('end', () => {
      if (!msg.author.authenticated) {
        msg.author.send('Authentication timed out.');
      }
    });
  }
});

// Generate an authentication URL for the user
function generateAuthURL(userId) {
  const redirectURI = encodeURIComponent('YOUR_REDIRECT_URL');
  const scopes = 'identify';
  const clientID = 'YOUR_CLIENT_ID';

  return `https://discord.com/api/oauth2/authorize?client_id=${clientID}&redirect_uri=${redirectURI}&response_type=code&scope=${scopes}&state=${userId}`;
}

// Exchange the authorization code for an access token
async function getAccessToken(code) {
  const redirectURI = encodeURIComponent('YOUR_REDIRECT_URL');
  const clientID = 'YOUR_CLIENT_ID';
  const clientSecret = 'YOUR_CLIENT_SECRET';

  const res = await fetch('https://discord.com/api/oauth2/token', {
    method: 'POST',
    headers: {
      'Content-Type': 'application/x-www-form-urlencoded',
    },
    body: `grant_type=authorization_code&code=${code}&redirect_uri=${redirectURI}&client_id=${clientID}&client_secret=${clientSecret}`,
  });

  return await res.json();
}

client.login(token);

// There are n rings and each ring is either red, green, or blue. The rings are distributed across ten rods labeled from 0 to 9.

// You are given a string rings of length 2n that describes the n rings that are placed onto the rods. Every two characters in rings forms a color-position pair that is used to describe each ring where:

// The first character of the ith pair denotes the ith ring's color ('R', 'G', 'B').
// The second character of the ith pair denotes the rod that the ith ring is placed on ('0' to '9').
// For example, "R3G2B1" describes n == 3 rings: a red ring placed onto the rod labeled 3, a green ring placed onto the rod labeled 2, and a blue ring placed onto the rod labeled 1.

// Return the number of rods that have all three colors of rings on them.


let rings = "B0B6G0R6R0R6G9";
var countPoints = function(rings) {
    
    let sum = 0;
    
	// Always 10 Rods
    for (let i = 0; i < 10; i++) {
        if (rings.includes(`B${i}`) && rings.includes(`G${i}`) && rings.includes(`R${i}`)) {
            sum+=1;
        }
    }
    
    return sum;
    
};

console.log(countPoints(rings));

//JavaScript program to swap two variables

//take input from the users
let a = prompt('Enter the first variable: ');
let b = prompt('Enter the second variable: ');

// XOR operator
a = a ^ b
b = a ^ b
a = a ^ b

console.log(`The value of a after swapping: ${a}`);
console.log(`The value of b after swapping: ${b}`);