const express = require('express');
const db = require('./db');
const bodyParser = require('body-parser');

const app = express();
const jsonParser = bodyParser.json({ extended: false });
const PORT = 4000;

//Generate a key within stupid&simple algorithm
function keyGen() {
    return Math.floor(Math.random() * (4 - 1)) + 1; //returning a random (расширить генерацию с применением MD5)
                                                    // value from 1 to 3
}

//killing a key after 1 minute pass(setting it to NULL)
function killKey() {
    return db.models.users.findAll().then((rows) => {
        let promises = [];
        for (let i in rows) {
            console.log('hello');

            let difference = new Date().getTime() - rows[i].dataValues.updatedAt.getTime(); // unixtime

            if(difference > 60 * 1000) { //if diff more than 1 min setting key to NULL
                promises.push(rows[i].update({
                    key: null
                }));
            }
        }

        return Promise.all(promises); //  ждём завершения всех промисов
    });
}

app.use('/auth',jsonParser,function (req, res, next) {
    killKey(); // killing a keys

    let clientKey;

    if (!req.headers.cookie) {
        clientKey = null;
    } else {
        clientKey = req.headers.cookie; // TODO: fix it (parse cookies)
    }

    return db.models.users.findOne({
        where: {
            login: req.body.login,
            password: req.body.password,
            key: clientKey
        }
    }).then(row => {
        if (row === null) {
            res.send('session expired relog in please');
        } else {
            next();
        }
    });
});

app.route('/auth')
    .post(jsonParser, (req,res) => {
        return db.models.users.findUser(req.body.login, req.body.password)
            .then(user => {
                if (user !== null) { // logged correct
                    if (!req.headers.cookie) { // if the req has no key server send it within the object
                        let key;
                        key = keyGen();
                        return user.update({
                            key // fixed (shorter)
                        });
                    } else {
                        throw new Error('key is valid, u re authorized')
                    }
                } else { //no comb like this
                    throw new Error('No such user with login and password');
                }
            }).then(() => {
                return db.models.users.findUser(req.body.login, req.body.password);
            }).then(user => {
                res.json(user.dataValues);//sending the obj with the new key to the client
            }).catch(e => res.status(500).send(e.msg));
    });

app.route('/reg')
    .post(jsonParser, (req,res) => {
        return db.models.users.findUser(req.body.login, req.body.password).then(user => {
            if (user === null) {
                return db.models.users.regUser(req.body.login, req.body.login).then(() => { // fix promise chaining
                   res.send('registred successfully');
                });
            } else {
                res.send('this log&pass combination is already exist');
            }
        });
    });

app.listen(PORT, '127.0.0.1', (err) => {
    if(err) {
        console.error(err.message);
    } else {
        console.log('listening to port ' + PORT);
    }
});