const database = require('./../database');
const passport = require('passport');
const localStrategy = require('passport-local').Strategy;
const bcrypt = require('bcrypt');

class User {
    constructor(id, email, isAdmin, name) {
        this.id = id;
        this.email = email;
        this.isAdmin = isAdmin;
        this.name = name;
    }
}


async function checkForAdminAccount() {

    const adminUsersQuery = `SELECT *
            FROM accounts.users
            WHERE admin = true;`;
    const adminUsers = await database.executeQuery(adminUsersQuery);

    if(adminUsers.length == 0) {
        const passwordHash = await generateHash('admin');
        const createTempAdminQuery = `INSERT INTO accounts.users(email, password, admin)
                VALUES('admin@example.com', $1, true);`;
        database.executeQuery(createTempAdminQuery, [passwordHash]);
        console.log("Created temp admin account 'admin@example.com' with password 'admin'.");
    }
}
database.initializationStatus.then(() => checkForAdminAccount());


passport.use(new localStrategy({
        usernameField: 'email',
        passwordField: 'password'},
    (username, password, cb) => {
    query = `SELECT user_id, email, password, admin
            FROM accounts.users
            WHERE email = $1`;
    database.executeQuery(query, [username])
        .then(result => {
            if(result.length > 0) {
                const first = result[0];
                const matches = bcrypt.compareSync(password, first[2]);
                if(matches) {
                    return cb(null, { id: first[0], email: first[1], admin: first[3] })
                }
                else
                {
                    return cb(null, false)
                }
            } else {
                return cb(null, false)
            }
        });
}));

passport.serializeUser((user, done) => {
    done(null, user.id)
})

passport.deserializeUser((id, cb) => {
    query = `SELECT user_id, email, admin
            FROM accounts.users
            WHERE user_id = $1`;
    database.executeQuery(query, [parseInt(id, 10)])
        .then(result => {
            cb(null, result[0]);
        });
});


async function generateHash(password) {
    const salt = bcrypt.genSaltSync();
    return bcrypt.hashSync(password, salt);
}

async function create(email, password, isAdmin, name) {
    const hash = await generateHash(password);

    const query = `INSERT INTO accounts.users(email, password, admin, full_name)
            VALUES($1, $2, $3, $4)`;
    await database.executeQuery(query, [email, hash, isAdmin, name]);
}

async function edit(id, email, password, isAdmin, name) {
    if(password) {
        const hash = await generateHash(password);

        const query = `UPDATE accounts.users
                SET email = $2,
                    password = $3,
                    admin = $4,
                    full_name = $5
                WHERE user_id = $1;`;
        await database.executeQuery(query, [id, email, hash, isAdmin, name]);
    } else {
        const query = `UPDATE accounts.users
                SET email = $2,
                    admin = $3,
                    full_name = $4
                WHERE user_id = $1;`;
        await database.executeQuery(query, [id, email, isAdmin, name]);
    }
    return new User(id, email, isAdmin, name);
}

async function remove(id) {
    const query = `DELETE FROM accounts.users
            WHERE user_id = $1
            RETURNING email, admin, full_name;`;
    const row = (await database.executeQuery(query, [id]))[0];
    return new User(id, row[0], row[1], row[2]);
}

async function retrieveAll() {
    const query = `SELECT user_id, email, admin, full_name
            FROM accounts.users
            ORDER BY full_name;`;
    const table = await database.executeQuery(query);

    const accountsList = [];
    table.forEach((row) => {
        accountsList.push(new User(row[0], row[1], row[2], row[3]));
    });
    return accountsList;
}

async function getFromID(id) {
    const query = `SELECT user_id, email, admin, full_name
            FROM accounts.users
            WHERE user_id = $1;`;
    const row = (await database.executeQuery(query, [id]))[0];

    return new User(id, row[1], row[2], row[3]);
}

exports.create = create;
exports.edit = edit;
exports.remove = remove;
exports.retrieveAll = retrieveAll;
exports.getFromID = getFromID;
exports.passport = passport;