DDD Car entity

car

<?php

namespace CoreDomain\Car;

class Car
{
    private $id;
    private $make;
    private $model;
    private $registrationNumber;
    private $color;
    private $engineSize;
    private $category;
    private $dateOwned;
    
    public function __construct($make, $model, RegistrationNumber $registrationNumber, AvailableColor $color, $engineSize, AvailableCategory $category)
    {
        $this->make = $make;
        $this->model = $model;
        $this->registrationNumber = $registrationNumber;
        $this->color = $color;
        $this->engineSize = $engineSize;
        $this->category = $category;
        // stamp the time that we owned the car
        $this->dateOwned = new \DateTime;
    }
    
    public static function register($make, $model, RegistrationNumber $registrationNumber, AvailableColor $color, $engineSize, AvailableCategory $category)
    {
        return new self($make, $model, $registrationNumber, $color, $engineSize, $category);
    }
    
    public function changeRegistrationNumber(RegistrationNumber $registrationNumber)
    {
        $this->registrationNumber = $registrationNumber;
    }
    
    public function repaint(AvailableColor $color)
    {
        $this->color = $color;
    }
    
    public function engineTune($engineSize)
    {
        $this->engineSize = $engineSize;
    }
    
    /**
     * If we have owned the car for over 3 years, then we need to sell this car as we dont want to a fleet of old cars
     *
     * @return boolean
     */
    public function isReadyForSale()
    {
        $today = new \DateTime;
        
        return $today->diff($this->dateOwned)->format('y') >= 3;
    }
    
    
}