const express = require('express');
const sha256 = require("sha256");
const jwt = require('jsonwebtoken');
const { getConnection, getUserByUsername, addUser, setUserPfp, setUserUsername, setUserPassword, setUserDescription } = require('../libs/mysql');
const { checkAuth } = require('../libs/middlewares');
const multer  = require('multer')
const rateLimit = require("express-rate-limit");
const slowDown = require("express-slow-down");
const fs = require('node:fs');

const upload = multer({ dest: 'data/pfps/' })
upload.limits = {
    fileSize: 1024 * 1024 * 5,
    files: 1,
};

const limiter = rateLimit({
    windowMs: 3 * 1000,
    max: 2,
});
  
const speedLimiter = slowDown({
    windowMs: 1 * 1000,
    delayAfter: 2,
    delayMs: () => 5000,
});

const router = express.Router();

router.post('/login', speedLimiter, limiter, async (req, res) => {
    const { username, password } = req.body;

    if (!username || !password) {
        return res.status(400).send({ error: 'Invalid username or password' });
    }

    const connection = await getConnection();
    const user = await getUserByUsername(connection, username);
    connection.end();
    if (user[0]) {
        if (user[0].password === sha256(password)) {
            const token = jwt.sign({ id: user[0].id }, process.env.JWT_SECRET, {
                expiresIn: 1000 * 60 * 60 * 24 * 7,
            });
            return res.send({ token: token });
        }
    }
    res.status(401).send({ error: 'Invalid username or password' });
});

router.post('/register', speedLimiter, limiter, async (req, res) => {
    const { username, password } = req.body;
    const connection = await getConnection();

    if (!username || !password) {
        connection.end();
        return res.status(400).send({ error: 'Invalid username or password' });
    }

    const user = await getUserByUsername(connection, username);
    if (user[0]) {
        connection.end();
        return res.status(401).send({ error: 'Username already exists' });
    }

    if (!/^[a-zA-Z0-9-_]+$/.test(username)) {
        connection.end();
        return res.status(400).send({ error: 'Invalid username' });
    }

    const hash = sha256(password);
    await addUser(connection, username, hash);
    connection.end();

    req.sockets.emit({
        type: 'new_user',
        username: username,
    });

    res.send({ message: 'User added' });
});

router.post('/me', checkAuth, async (req, res) => {
    const user = req.user;
    res.send({ id: user.id, username: user.username, admin: user.admin , description: user.description });  
});

router.post('/me/uploadpfp', upload.single('pfp'), checkAuth, async (req, res) => {
    const fileName = req.file.filename;
    const user = req.user;

    if (user.pfp && fs.existsSync(`data/pfps/${user.pfp}`)) {
        fs.unlinkSync(`data/pfps/${user.pfp}`);
    }

    const connection = await getConnection();
    await setUserPfp(connection, user.id, fileName);
    connection.end();
    res.send({ message: 'Profile picture uploaded.' });  
});

router.post('/me/deletepfp', checkAuth, async (req, res) => {
    const user = req.user;

    if (user.pfp && fs.existsSync(`data/pfps/${user.pfp}`)) {
        fs.unlinkSync(`data/pfps/${user.pfp}`);
    }

    const connection = await getConnection();
    await setUserPfp(connection, user.id, null);
    connection.end();
    res.send({ message: 'Profile picture deleted.' });  
});

router.post('/me/setusername', checkAuth, async (req, res) => {
    const { username } = req.body;
    const user = req.user;

    if (!username) {
        return res.status(400).send({ error: 'Invalid username' });
    }

    if (!/^[a-zA-Z0-9-_]+$/.test(username)) {
        return res.status(400).send({ error: 'Invalid username' });
    }

    const connection = await getConnection();
    const userExists = await getUserByUsername(connection, username);
    if (userExists[0]) {
        connection.end();
        return res.status(401).send({ error: 'Username already exists' });
    }

    await setUserUsername(connection, user.id, username);
    connection.end();
    res.send({ message: 'Username changed.' });  
});


router.post('/me/setpassword', checkAuth, async (req, res) => {
    const { oldPassword, password } = req.body;
    const user = req.user;

    if (!password || !oldPassword || sha256(oldPassword) !== user.password) {
        return res.status(400).send({ error: 'Invalid password' });
    }

    const connection = await getConnection();
    await setUserPassword(connection, user.id, sha256(password));
    connection.end();
    res.send({ message: 'Password changed.' });  
});

router.post('/me/setdescription', checkAuth, async (req, res) => {
    const { description } = req.body;
    const user = req.user;

    if (!description) {
        return res.status(400).send({ error: 'Invalid description' });
    }

    const connection = await getConnection();
    await setUserDescription(connection, user.id, description);
    connection.end();
    res.send({ message: 'Description changed.' });  
});

module.exports = router;