const faker = require('faker');
const mysql = require('mysql');

const connection = mysql.createConnection({
    host     : 'localhost',
    user     : 'root',
    database : 'db_books'
});

const firstName = 'Bill';
const lastName = 'Reinger';

connection.connect();


function getQuery(sql, params){
    return new Promise((resolve, reject) => {
        connection.query(sql,params,function (error, results, fields){
            if (error) {
                reject(error);
            }
            resolve(results);

        });
    });
}

let sql = 'SELECT * FROM `authors` WHERE first_name=? and last_name=? limit 1;';

getQuery(sql,[firstName, lastName])

    .then(authors=>{
        sql = 'SELECT * FROM `books_authors` WHERE author_id=?;';
        return getQuery(sql,[authors[0].id]);
    })
    .then(books_authors=>{
        sql = 'SELECT * FROM `books` WHERE id IN (?);';
        const args = books_authors.map(b_a => b_a.book_id);
        return getQuery(sql,[args]);
    })
    .then(books => {
        console.log(books);
    })
    .catch(error => {
        console.log(error);
    })
    .finally(()=>{
        connection.end();
    });


// let sql = 'SELECT * FROM `authors` WHERE first_name=? and last_name=? limit 1;';
// connection.query(sql,[firstName, lastName], function (error, results, fields) {
//     if (error) throw error;
//     let authorId = results[0].id;
//         sql = 'SELECT * FROM `books_authors` WHERE author_id=?;';
//         connection.query(sql,[authorId], function (error, books_authors, fields) {
//             console.log(books_authors);
//             sql = 'SELECT * FROM `books` WHERE id IN (?);';
//             const args = books_authors.map(b_a => b_a.book_id);
//             connection.query(sql,[args],function (error, books, fields)            {
//                 if (error) throw error;
//                 console.log(books);
//                 connection.end();
//             });
//         });
//
//
//     console.log(authorId);
// });