<?php
final class DbHelper
{
    private const host = "localhost";
    private const user = "root";
    private const pass = "marcin";
    private const database = "ai_shop";
    private static $conn;
    public static function Instance()
    {
        static $instance = null;
        if ($instance === null) {
            $instance = new DbHelper;
        }
        return $instance;
    }
    public function getProducts()
    {
        return self::$conn->query("select * from product utf8");
    }
    private function __construct()
    {
        self::$conn = new mysqli(self::host, self::user, self::pass, self::database);
        self::$conn->set_charset("utf8");
        if (self::$conn->connect_error) {
            die("Connection failed: " . self::$conn->connect_error);
        }
    }
    public function __destruct()
    {
        self::$conn->close();
    }
}