var fs = require('fs');
var mysql = require('mysql');
var after = require('lodash.after');
var mkdirp = require('mkdirp');

if(process.argv.length <= 2) {
    process.exit();
}

var challenge_id = process.argv[2];

var connection = mysql.createConnection({
    host: '127.0.0.1',
    user: 'cheatTest',
    password: 'che@tTest',
    database: 'judge'
});

connection.connect();

connection.query(
     'SELECT challenge_prob.problem_id' +
    ' FROM challenge_prob' +
    ' INNER JOIN problem' +
    ' ON problem.problem_id = challenge_prob.problem_id' +
    ' WHERE challenge_prob.challenge_id = ' + challenge_id,
    (err, rows) => {
        if(err) {
            console.log(err);
            return;
        }
        var done = after(rows.length, () => {
            process.exit();
        });
        rows.forEach( row => {
            prob_process(challenge_id, row.problem_id, done);
        });
    }
);

function prob_process(chal_id, prob_id, done) {
    connection.query(
         'SELECT s.submission_id, s.challenge_id, s.problem_id, s.submission_date, s.submission_code,' +
        ' u.student_id, u.user_level' +
        ' FROM user as u' +
        ' INNER JOIN (' +
        '   SELECT s1.submission_id, s1.challenge_id, s1.problem_id,' +
        '   s1.user_id, s1.submission_date, s1.submission_code' +
        '   FROM submission as s1' +
        '   INNER JOIN (' +
        '     SELECT MAX(submission_id) as id' +
        '     FROM submission' +
        '     WHERE challenge_id = ' + chal_id +
        '     AND problem_id = ' + prob_id +
        '     GROUP BY user_id' +
        '   ) as s2 ON s1.submission_id = s2.id' +
        ' ) as s ON s.user_id = u.user_id' +
        ' WHERE u.user_level = 1',
        (err, rows) => {
            if(err) {
                console.log(err);
                done();
                return;
            }
            mkdirp('./' + prob_id, (err) => {
                if(err) {
                    console.log(err);
                    done();
                    return;
                }
                rows.forEach( item => {
                    fs.writeFileSync(prob_id + '/' + item.student_id + '.cpp', item.submission_code);
                    console.log(prob_id + '/' + item.student_id + '.cpp ' + item.submission_id + ' done!');
                });
                done();
            });
        }
    );
}