import java.io.Serializable;
import java.io.FileOutputStream;
import java.io.FileInputStream;
import java.io.ObjectOutputStream;
import java.io.ObjectInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;

public class Car implements Serializable {
  private String make;
  private int year;
  private static final long serialVersionUID = 1L;
  private Engine engine;

  public Car(String make, int year) {
    this.make = make;
    this.year = year;
    this.engine = new Engine(2.4, 6);
  }

 private void writeObject(ObjectOutputStream stream) throws IOException {
    stream.writeObject(this.make);
    stream.writeInt(this.year);
    stream.writeDouble(this.engine.getLiters());
    stream.writeInt(this.engine.getCylinders());   
  }
 
  private void readObject(ObjectInputStream stream) throws IOException, ClassNotFoundException {
    this.make = (String) stream.readObject();
    this.year = (int) stream.readInt();
    double liters = (double) stream.readDouble();
    int cylinders = (int) stream.readInt();
    this.engine = new Engine(liters, cylinders); 
  }    


  public String toString(){
    return String.format("Car make is: %s, Car year is: %d, %s", this.make, this.year, this.engine);
  }

  public static void main(String[] args) throws FileNotFoundException, IOException, ClassNotFoundException {
    Car toyota = new Car("Toyota", 2021);
    Car honda = new Car("Honda", 2020);
    FileOutputStream fileOutputStream = new FileOutputStream("cars.txt");
    ObjectOutputStream objectOutputStream = new ObjectOutputStream(fileOutputStream);
    objectOutputStream.writeObject(toyota);
    objectOutputStream.writeObject(honda);

    FileInputStream fileInputStream = new FileInputStream("cars.txt");
    ObjectInputStream objectInputStream = new ObjectInputStream(fileInputStream);

    Car toyotaCopy = (Car) objectInputStream.readObject();
    Car hondaCopy = (Car) objectInputStream.readObject();

    boolean isSameObject = toyotaCopy == toyota;
    System.out.println("Toyota (Copy) - "+toyotaCopy);
    System.out.println("Toyota (Original) - "+toyota);
    System.out.println("Is same object: "+ isSameObject);
  }
}