import { createHash, pbkdf2Sync, randomBytes } from "node:crypto";

let db;
let users;

export function initAuth(app, db) {
    users = db.collection('users');
    app.post('/auth/login', loginUser);
}

async function loginUser(req, res) {
    const username = req.body.username;
    const password = req.body.password;

    let userCount = await users.estimatedDocumentCount();
    let sessiontoken = null;
    if (userCount <= 0) {
        // create first user
        sessiontoken = await createUser(username, password, 'admin');
    } else {
        // authenticate user
        sessiontoken = await authenticateUser(username, password);
    }

    if (sessiontoken !== null) {
        const expires = new Date();
        expires.setDate(expires.getDate() + 1);

        res.cookie('jeopardytoken', sessiontoken, {
            maxAge: 1e3 * 60 * 60 * 24
        })

        res.sendStatus(200);
    } else {
        res.sendStatus(403);
    }
}

async function createUser(username, password, role) {
    const salt = randomBytes(128).toString('base64');
    const iterations = Math.floor(Math.random() * 5000) + 5000;
    const hash = generateHash(password, salt, iterations);

    const sessiontoken = generateSessionToken();

    await users.insertOne({
        username,
        role,
        salt,
        iterations,
        hash,
        sessiontoken
    });

    return sessiontoken;
}

async function authenticateUser(username, password) {
    let foundUser = await users.findOne({username});
    if (foundUser === null) return null;

    const hash = generateHash(password, foundUser.salt, foundUser.iterations);

    if (hash === foundUser.hash) {
        const sessiontoken = generateSessionToken();
        await users.updateOne({_id: foundUser._id}, {$set: {
            sessiontoken
        }});
        return sessiontoken;
    }

    return null;
}

function generateSessionToken() {
    return randomBytes(128).toString('base64');
}

function generateHash(password, salt, iterations) {
    return pbkdf2Sync(password, salt, iterations, 128, 'sha512').toString('hex');
}