import express from 'express';
import { mongoose } from 'mongoose';
import bcrypt from "bcrypt";
import jwt from "jsonwebtoken";
import {SECRET_KEY} from "../passport.js";
import {isValidEmail} from "../utils.js";

/**
 * Create an Express router instance.
 *
 * @type {Express.Router}
 */
const router = express.Router();

/**
 * Set the salt rounds for password hashing (10).
 *
 * @type {number}
 */
const saltRounds = 10;

/**
 * Define a Mongoose schema for users.
 *
 * @typedef {Object} UserSchema
 * @property {String} email - The user's email address.
 * @property {String} password - The user's password.
 */

/**
 * Create a new Mongoose model from the user schema.
 *
 * @type {Model<UserSchema>}
 */
const userSchema = new mongoose.Schema({
    /**
     * The user's email address.
     *
     * @type {String}
     * @required
     */
    email: {
        type: String,
        required: true
    },
    /**
     * The user's password.
     *
     * @type {String}
     * @required
     */
    password: {
        type: String,
        required: true
    }
})
const User = mongoose.model('User', userSchema, 'users');

/**
 * Generate a JWT token for the given user.
 *
 * @param {Object} user - The user object.
 * @returns {String} The generated JWT token.
 */
function generateToken(user) {
    const payload = { id: user._id };
    return jwt.sign(payload, SECRET_KEY, {expiresIn: '6h'});
}

/**
 * Handle a login request.
 */
router.post('/login', function (req, res) {
    const email = req.body.email;
    const password = req.body.password;

    if (!password || !email) {
        return res.status(400).json({ message: 'parameters invalid' });
    }

    if (!isValidEmail(email)) {
        return res.status(400).json({ message: 'email is invalid' });
    }

    User.findOne({ email: email })
        .then(user => {
            if (!user) {
                return res.status(422).json({ message: 'user not found' });
            }
            bcrypt.compare(password, user.password, function (err, result) {
                if (result) {
                    res.json({ token: generateToken(user) });
                } else {
                    res.status(401).json({ error: "Wrong password" });
                }
            });
        })
        .catch(err => {
            console.log(err);
            res.status(500).json({ error: err.message }); 
        });
});

/**
 * Handle a registration request.
 */
router.post('/register', async function (req, res) {
    const email = req.body.email;
    const password = req.body.password;

    if (!password || !email) {
        return res.status(400).json({ message: 'parameters invalid' });
    }

    if (!isValidEmail(email)) {
        return res.status(400).json({ message: 'email is invalid' });
    }

    try {
        const existingUser = await User.findOne({ email: email });
        if (existingUser) {
            return res.status(403).json({ message: 'user already exists' });
        }

        // Hash the password
        bcrypt.hash(password, saltRounds, async function (err, hash) {
            if (err) {
                return res.status(500).json({ error: err.message });
            } else if (hash) {
                await User.collection.insertOne({ email: email, password: hash });
                const user = await User.findOne({ email: email });
  
                return res.json({ token: generateToken(user) });
            }
        });
    } catch (err) {
        console.error(err);
        return res.status(500).json({ error: 'Internal Server Error' });
    }
});

export { router, User };