<?php
/**
 * Created by PhpStorm.
 * User: leanderschmedemann
 * Date: 27/03/2017
 * Time: 14:07
 */

require_once('includes.inc.php');
$data = '';
$error = 0;
$values = null;
$uid = isset($_GET['uid']) ? $_GET['uid'] : '';
$length = isset($_GET['length']) ? $_GET['length'] : '';
$length = (($length === '0') || ($length && gettype(+$length) == 'integer')) ? +$_GET['length'] : 10;
$db = new Database();
$questions_count = $db->query('SELECT COUNT(*) FROM "Questions"')['data'][0]['count'];

// Return $count random, non repeating numbers in range from $min to $max.
function random_numbers($min, $max, $count){
    $numbers = range($min, $max);
    shuffle($numbers);
    return array_slice($numbers, 0, $count);
}

if($uid == '') {
    $error = 12101;
} else if($length == 0) {
    $error = 12102;
} else if($length > $questions_count) {
    $error = 12103;
    $values = array($questions_count);
} else {
    // Delete existing game for user.
    if($db->query('SELECT EXISTS (SELECT 1 FROM "Games" WHERE "ID" = $1)', array($uid))['data'][0]['exists'] == 't') {
        $db->query('DELETE FROM "Games" WHERE "ID" = $1', array($uid));
    }
    // Create new game for user.
    $db->query('INSERT INTO "Games" ("ID") VALUES ($1)', array($uid));
    if(preg_match('/violates foreign key constraint "Games_ID_fkey"/', pg_last_error()) == 1) {
        $error = 12104;
    }
    // Find questions for new game and insert into table.
    $questions = random_numbers(0, $questions_count-1, $length);
    foreach($questions as $question) {
        $q = $db->query('SELECT "ID" FROM "Questions" OFFSET $1 LIMIT 1', array($question))['data'][0]['ID'];
        $db->query('INSERT INTO "GamesQuestions" ("Games_ID", "Questions_ID") VALUES ($1, $2)', array($uid, $q));
    }
}

$next_question = Question::get_next_question($db, $uid);
$data = array('next' => $next_question);

$response = Database::create_response($data, $error, $values);
print_r($response);
?>