<?php

declare(strict_types=1);


class Car {
    private $brandName = "";
    private $doorsCount = 0;
    private $fuelType = "";

    private static $instance = null;

    public function __construct() {
        if (self::$instance === null) {
            self::$instance = $this;
        }
    }

    private static function getInstance() : Car { // Car or self instead (?) -> Both just works fine, but i don't know about its scope.
        return self::$instance;
    }

    public function getBrandName() : string {
        return $this->brandName;
    }

    public function setBrandName(string $brandName) : Car {
        $this->brandName = $brandName;
        return Car::getInstance();
    }

    public function getDoorsCount() : int {
        return $this->doorsCount;
    }

    public function setDoorsCount(int $count) : Car {
        $this->doorsCount = $count;
        return Car::getInstance();
    }

    public function getFuelType() : string {
        return $this->fuelType;
    }

    public function setFuelType(string $fuelType) : Car {
        $this->fuelType = $fuelType;
        return Car::getInstance();
    }

    public function __toString() : string {
        return "Car{brandName:'$this->brandName',doorsCount:'$this->doorsCount',fuelType:'$this->fuelType'}";
    }
}

$car = (new Car())
        ->setBrandName("Ferrari")
        ->setDoorsCount(2)
        ->setFuelType("Shell V-Performance");

echo $car . PHP_EOL;