import java.io.Serializable;
import java.util.ArrayList;
import java.util.List;

/** Una lista de canciones que se puede serializar. */
public class Playlist implements Serializable {
    private static final long serialVersionUID = 1L;

    private final String name;
    private final ArrayList<Song> songs = new ArrayList<>();
    private transient int totalSeconds;      // se recalcula; no se guarda

    public Playlist(String name) {
        this.name = name;
    }

    public void add(Song song) {
        songs.add(song);
        totalSeconds += song.seconds();
    }

    public String name() {
        return name;
    }

    public List<Song> songs() {
        return List.copyOf(songs);
    }

    public int totalSeconds() {
        return totalSeconds;
    }
}