import java.awt.Point;
import java.util.ArrayList;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;

public class Model {
	private ArrayList<Point> points;
	private ArrayList<ModelListener> listeners;

	/**
	 * Constructor
	 */
	public Model() {
		points = new ArrayList<Point>();
		listeners = new ArrayList<ModelListener>();
		if (new java.io.File("points.bin").exists()) {
			// load points from file
			try {
				FileInputStream fi = new FileInputStream("points.bin");
				ObjectInputStream in = new ObjectInputStream(fi);
				points = (ArrayList<Point>) in.readObject();
				in.close();
				fi.close();
			} catch (IOException e) {
				System.err.println(e.getMessage());
				System.exit(1);
			} catch (ClassNotFoundException e) {
				System.err.println(e.getMessage());
				System.exit(1);
			}
		}
	}

	public void addListener(ModelListener l) {
		listeners.add(l);
	}

	public ArrayList<Point> getPoints() {
		return points;
	}

	public void addPoint(Point p) {
		points.add(p);
		notifyListeners();
	}

	public void clearAllPoints() {
		points.clear();
		notifyListeners();
	}

	public void deleteLastPoint() {
		if (points.size() > 0) {
			points.remove(points.size() - 1);
			notifyListeners();
		}
	}

	private void notifyListeners() {
		for (ModelListener l : listeners) {
			l.update();
		}
	}

	public int numberOfPoints() {
		return points.size();
	}

	public void saveData() {
		try {
			// save points to file
			FileOutputStream fo = new FileOutputStream("points.bin");
			ObjectOutputStream out = new ObjectOutputStream(fo);
			out.writeObject(points);
			out.close();
			fo.close();
		} catch (IOException e) {
			System.err.println(e.getMessage());
			System.exit(1);
		}
	}

	public static void testModel() {
		Model m = new Model();
		m.addListener(new ModelListener() {
			@Override
			public void update() {
				System.out.println(true + " (listener)");
			}
		});
		System.out.println(m.getPoints() == m.points);
		Point p1 = new Point(1, 2);
		Point p2 = new Point(3, 4);
		m.addPoint(p1);
		m.addPoint(p2);
		System.out.println(m.numberOfPoints() == 2);
		System.out.println(m.points.get(0) == p1);
		System.out.println(m.points.get(1) == p2);
		m.deleteLastPoint();
		System.out.println(m.numberOfPoints() == 1);
		System.out.println(m.points.get(0) == p1);
		m.clearAllPoints();
		System.out.println(m.numberOfPoints() == 0);
		m.notifyListeners();
	}
}