<?php
if (!defined('SVRJS_MOD_DIRECTORY')) die;

$requiredExtensions = ['mysqli'];

if (HCAPTCHA_ENABLED || STOPFORUMSPAM_ENABLED) array_push($requiredExtensions, 'json', 'curl');
if (COMPRESSION_ENABLED) array_push($requiredExtensions, 'zlib');

foreach ($requiredExtensions as $requiredExtension) {
    if (!extension_loaded($requiredExtension)) {
        die("The required PHP extension isn't loaded - " . htmlspecialchars($requiredExtension));
    }
}

include 'utils.php';

$mysqlDriver = new mysqli_driver();
$mysqlDriver->report_mode = MYSQLI_REPORT_OFF;

$connection = new mysqli(
    MYSQL_HOST,
    MYSQL_USERNAME,
    MYSQL_PASSWORD,
    MYSQL_DATABASE,
    MYSQL_PORT
);

if ($connection->connect_error) die("Error connecting to a database.");

// Custom session handler functions
class MySQLSessionHandler
{
    private $mysqli;

    public function __construct($mysqli)
    {
        $this->mysqli = $mysqli;
    }

    public function open($savePath, $sessionName)
    {
        return true;
    }

    public function close()
    {
        return true;
    }

    public function read($id)
    {
        $data = null;
        $stmt = $this->mysqli->prepare("SELECT data FROM sessions WHERE id = ?");
        if (!$stmt) return '';
        $stmt->bind_param('s', $id);
        $stmt->execute();
        $stmt->bind_result($data);
        $stmt->fetch();
        $stmt->close();
        return isset($data) && $data ? $data : '';
    }

    public function write($id, $data)
    {
        $stmt = $this->mysqli->prepare("REPLACE INTO sessions (id, data) VALUES (?, ?)");
        if (!$stmt) return false;
        $stmt->bind_param('ss', $id, $data);
        return $stmt->execute();
    }

    public function destroy($id)
    {
        $stmt = $this->mysqli->prepare("DELETE FROM sessions WHERE id = ?");
        if (!$stmt) return false;
        $stmt->bind_param('s', $id);
        return $stmt->execute();
    }

    public function gc($maxlifetime)
    {
        return true;
    }

    public function create_sid()
    {
        if (function_exists('random_bytes')) {
            $sid = bin2hex(random_bytes(32));
        } else {
            $sid = '';
            for ($i = 0; $i < 32; $i++) {
                $sid = $sid . bin2hex(rand(0, 255));
            }
        }
        return $sid;
    }

    public function validate_sid($key)
    {
        $stmt = $this->mysqli->prepare("SELECT data FROM sessions WHERE id = ?");
        if (!$stmt) return false;
        $stmt->bind_param('s', $key);
        $stmt->execute();
        $result = $stmt->get_result();
        if (!$result) {
            $stmt->close();
            return false;
        } else {
            $valid = boolval($result->fetch_assoc());
            $stmt->close();
            return $valid;
        }
    }
}