const { authenticate, createSession, validateSession } = require('../acl');
const cookie = require('cookie');
const users = require('../users'); // Hardcoded users
const { User, Achievement } = require('../models'); // Sequelize models
const { getLearningContent } = require('../openai');
const bcrypt = require('bcrypt');

// Function to handle user login
const loginUser = async (req, res) => {
    let body = '';
    req.on('data', chunk => {
        body += chunk.toString();
    });
    req.on('end', async () => {
        try {
            const { username, password } = JSON.parse(body);
            let user = await User.findOne({ where: { username } });
            if (!user && users[username]) {
                user = { username, password: users[username].password, role: users[username].role };
            }

            if (user && bcrypt.compareSync(password, user.password)) {
                const token = await createSession(username);
                res.setHeader('Set-Cookie', cookie.serialize('token', token, {
                    httpOnly: true,
                    maxAge: 3600 // 1 hour
                }));
                res.writeHead(200, { 'Content-Type': 'application/json' });
                res.end(JSON.stringify({ message: 'Login successful', token }));
            } else {
                res.writeHead(401, { 'Content-Type': 'application/json' });
                res.end(JSON.stringify({ error: 'Invalid username or password' }));
            }
        } catch (err) {
            res.writeHead(400, { 'Content-Type': 'application/json' });
            res.end(JSON.stringify({ error: 'Invalid request format - ' + err }));
        }
    });
};

// Function to handle user registration
const registerUser = async (req, res) => {
    let body = '';
    req.on('data', chunk => {
        body += chunk.toString();
    });
    req.on('end', async () => {
        try {
            const { username, password, role } = JSON.parse(body);
            if (!username || !password || !role) {
                res.writeHead(400, { 'Content-Type': 'application/json' });
                res.end(JSON.stringify({ error: 'Missing required fields' }));
                return;
            }

            const existingUser = await User.findOne({ where: { username } });
            if (existingUser || users[username]) {
                res.writeHead(409, { 'Content-Type': 'application/json' });
                res.end(JSON.stringify({ error: 'User already exists' }));
                return;
            }

            // Save user to the database
            await User.create({ username, password, role });

            // Save user to the hardcoded users list
            users[username] = { password, role };

            res.writeHead(200, { 'Content-Type': 'application/json' });
            res.end(JSON.stringify({ message: 'User registered successfully' }));
        } catch (err) {
            res.writeHead(400, { 'Content-Type': 'application/json' });
            res.end(JSON.stringify({ error: 'Invalid request format' }));
        }
    });
};

// Function to fetch user achievements
const fetchAchievements = async (req, res) => {
    try {
        const session = await validateSession(req.cookies.token);
        if (session && session.data.user) {
            const achievements = await Achievement.findAll({ where: { userId: session.data.user.id } });
            res.writeHead(200, { 'Content-Type': 'application/json' });
            res.end(JSON.stringify(achievements));
        } else {
            res.writeHead(401, { 'Content-Type': 'application/json' });
            res.end(JSON.stringify({ error: 'Unauthorized' }));
        }
    } catch (err) {
        res.writeHead(500, { 'Content-Type': 'application/json' });
        res.end(JSON.stringify({ error: 'Failed to fetch achievements' }));
    }
};

// Function to fetch learning content from OpenAI
const fetchLearningContent = async (req, res) => {
    let body = '';
    req.on('data', chunk => {
        body += chunk.toString();
    });
    req.on('end', async () => {
        try {
            const { prompt } = JSON.parse(body);
            const content = await getLearningContent(prompt);
            res.writeHead(200, { 'Content-Type': 'application/json' });
            res.end(JSON.stringify({ content }));
        } catch (err) {
            res.writeHead(500, { 'Content-Type': 'application/json' });
            res.end(JSON.stringify({ error: 'Failed to fetch learning content' }));
        }
    });
};

// Function to handle adding achievements
const addAchievement = async (req, res) => {
    let body = '';
    req.on('data', chunk => {
        body += chunk.toString();
    });
    req.on('end', async () => {
        try {
            const { userId, badge } = JSON.parse(body);
            if (!userId || !badge) {
                res.writeHead(400, { 'Content-Type': 'application/json' });
                res.end(JSON.stringify({ error: 'Missing required fields' }));
                return;
            }

            await Achievement.create({ userId, badge });
            res.writeHead(200, { 'Content-Type': 'application/json' });
            res.end(JSON.stringify({ message: 'Achievement added successfully' }));
        } catch (err) {
            res.writeHead(500, { 'Content-Type': 'application/json' });
            res.end(JSON.stringify({ error: 'Failed to add achievement' }));
        }
    });
};

// Export the API request handler
const handleApiRequest = (req, res) => {
    if (req.url === '/api/login' && req.method === 'POST') {
        loginUser(req, res);
    } else if (req.url === '/api/register' && req.method === 'POST') {
        registerUser(req, res);
    } else if (req.url === '/api/achievements' && req.method === 'GET') {
        fetchAchievements(req, res);
    } else if (req.url === '/api/achievements' && req.method === 'POST') {
        addAchievement(req, res);
    } else if (req.url === '/api/learning-content' && req.method === 'POST') {
        fetchLearningContent(req, res);
    } else {
        res.writeHead(404, { 'Content-Type': 'application/json' });
        res.end(JSON.stringify({ error: 'Not Found' }));
    }
};

module.exports = { handleApiRequest };