<?php

declare(strict_types=1);

namespace DTS;

class Session
{
    private static ?self $instance = null;

    private array $session = [];

    public static function getInstance()
    {
        if (!self::$instance) {
            self::$instance = new self();
        }

        return self::$instance;
    }

    private function __construct()
    {
        session_start();

        foreach ($_SESSION as $key => $value) {
            $this->session[$key] = $value;
            unset($_SESSION[$key]);
        }
    }

    public function set(string $key, $value): void
    {
        $this->session[$key] = $_SESSION[$key] = $value;
    }

    public function get(string $key, $default = null)
    {
        return $this->session[$key] ?? $default;
    }
}