server.js

const express = require('express');
const sqlite3 = require('sqlite3').verbose();
const bcrypt = require('bcrypt');
const path = require('path');

const app = express();
const port = 3000;

app.use(express.json());
app.use(express.static(path.join(__dirname, 'public')));

// Initialize SQLite database
const db = new sqlite3.Database('./users.db', (err) => {
    if (err) {
        console.error(err.message);
    }
    console.log('Connected to the users database.');
});

// Create users table if it doesn't exist
db.run(`CREATE TABLE IF NOT EXISTS users (
    id INTEGER PRIMARY KEY AUTOINCREMENT,
    username TEXT UNIQUE,
    email TEXT UNIQUE,
    password TEXT
)`);

// Register endpoint
app.post('/api/register', (req, res) => {
    const { username, email, password } = req.body;

    bcrypt.hash(password, 10, (err, hash) => {
        if (err) {
            return res.status(500).json({ message: 'Error hashing password' });
        }

        const sql = 'INSERT INTO users (username, email, password) VALUES (?, ?, ?)';
        db.run(sql, [username, email, hash], (err) => {
            if (err) {
                return res.status(400).json({ message: 'Username or email already exists' });
            }
            res.status(201).json({ message: 'User registered successfully' });
        });
    });
});

// Login endpoint
app.post('/api/login', (req, res) => {
    const { email, password } = req.body;

    const sql = 'SELECT * FROM users WHERE email = ?';
    db.get(sql, [email], (err, user) => {
        if (err) {
            return res.status(500).json({ message: 'Error querying database' });
        }
        if (!user) {
            return res.status(401).json({ message: 'Invalid email or password' });
        }

        bcrypt.compare(password, user.password, (err, result) => {
            if (err) {
                return res.status(500).json({ message: 'Error comparing passwords' });
            }
            if (!result) {
                return res.status(401).json({ message: 'Invalid email or password' });
            }
            res.status(200).json({ message: 'Login successful' });
        });
    });
});

app.listen(port, () => {
    console.log(`Server running at http://localhost:${port}`);
});