const express = require('express');
const bodyParser = require('body-parser');
const jwt = require('jsonwebtoken');
const app = express();

const accessTokenSecret = 'somerandomaccesstoken';
const refreshTokenSecret = 'somerandomstringforrefreshtoken';

const users = [
    {
        username: 'john',
        password: 'password123admin',
        role: 'admin'
    }, {
        username: 'anna',
        password: 'password123member',
        role: 'member'
    }
]

const authenticateJWT = (req, res, next) => {
    const authHeader = req.headers.authorization;

    if (authHeader) {
        const token = authHeader.split(' ')[1];
        //const token = authHeader;
        //console.log(`${authHeader} \n`);
        //console.log(`${token} \n`);
        //console.log(`${accessTokenSecret} \n`);
        //console.log(jwt.verify(token, accessTokenSecret));
        jwt.verify(token, accessTokenSecret, (err, user) => {
            if (err) {
                console.log('Bledny token');
                return res.sendStatus(403);
            }
            console.log('Poprawny token');
            req.user = user;
            next();
        });
    } else {
        res.sendStatus(401);
    }
}

const books = [
    {
        "author": "Chinua Achebe",
        "country": "Nigeria",
        "language": "English",
        "pages": 209,
        "title": "Things Fall Apart",
        "year": 1958
    },
    {
        "author": "Hans Christian Andersen",
        "country": "Denmark",
        "language": "Danish",
        "pages": 784,
        "title": "Fairy tales",
        "year": 1836
    },
    {
        "author": "Dante Alighieri",
        "country": "Italy",
        "language": "Italian",
        "pages": 928,
        "title": "The Divine Comedy",
        "year": 1315
    },
]

var refreshTokens = [];

app.use(bodyParser.json());

app.post('/login', (req, res) => {
    // read username and password from request body
    const { username, password } = req.body;

    // filter user from the users array by username and password
    const user = users.find(u => { return u.username === username && u.password === password });
    console.log(`${user.username} \n`);
    if (user) {
        // generate an access token
        const accessToken = jwt.sign({ username: user.username, role: user.role }, accessTokenSecret, { expiresIn: '3m' });
        const refreshToken = jwt.sign({ username: user.username, role: user.role }, refreshTokenSecret);

        refreshTokens.push(refreshToken);

        res.json({
            accessToken,
            refreshToken
        });
    } else {
        res.send('Username or password incorrect');
    }
});

app.post('/token', (req, res) => {
    const { token } = req.body;

    if (!token) {
        return res.sendStatus(401);
    }

    if (!refreshTokens.includes(token)) {
        return res.sendStatus(403);
    }

    jwt.verify(token, refreshTokenSecret, (err, user) => {
        if (err) {
            return res.sendStatus(403);
        }

        const accessToken = jwt.sign({ username: user.username, role: user.role }, accessTokenSecret, { expiresIn: '3m' });

        res.json({
            accessToken
        });
    });
});

app.post('/logout', (req, res) => {
    const { token } = req.body;
    refreshTokens = refreshTokens.filter(t => t !== token);

    res.send("Logout successful");
});

app.get('/books', authenticateJWT, (req, res) => {
    res.json(books);
});

app.post('/books', authenticateJWT, (req, res) => {
    const { role } = req.user;

    if (role !== 'admin') {
        return res.sendStatus(403);
    }


    const book = req.body;
    books.push(book);

    res.send('book added successfully');
});

app.listen(<port>, () => {
    console.log('Books service started on port <port>');
});