import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;

public class DisplayFrame extends JFrame
		implements ActionListener, ChangeListener, Runnable {

	// Action commands

	final static String CMD_STOP = "stop";
	final static String CMD_FWD = "fwd";
	final static String CMD_REV = "rev";

	// GUI components

	JPanel displayPanel;
	JButton revButton;
	JButton stopButton;
	JButton fwdButton;
	JLabel stateLabel;
	JSlider ndtSlider;

	// Thread sync components

	Lock runLock = new Lock();
	Lock displayLock = new Lock();
	Thread thread;

	// Simulation components

	sim s;
	int ndt;
	boolean direction;

	public DisplayFrame(sim sim_s) {
		s = sim_s;
		ndt = 50;
		direction = true;

		setTitle("Schroedinger Simulation");
		setDefaultCloseOperation(DISPOSE_ON_CLOSE);
		addWindowListener(new WindowAdapter () {
			public void windowClosed(WindowEvent e) {
				thread.interrupt();
			}
		});

		// Create GUI components

		displayPanel = new JPanel() {
			public void paintComponent(Graphics g) {
				super.paintComponent(g);
				Dimension d = getSize();
				s.render(g, d);
				displayLock.enable();
			}
		};
		displayPanel.setPreferredSize(new Dimension(640, 480));

		ndtSlider = new JSlider(0, 1000, ndt);
		ndtSlider.setMinorTickSpacing(50);
		ndtSlider.setMajorTickSpacing(200);
		ndtSlider.createStandardLabels(200);
		ndtSlider.setPaintTicks(true);
		ndtSlider.setPaintLabels(true);
		ndtSlider.addChangeListener(this);

		revButton = new JButton("<<");
		revButton.setActionCommand(CMD_REV);
		revButton.addActionListener(this);

		stopButton = new JButton("Stop");
		stopButton.setActionCommand(CMD_STOP);
		stopButton.addActionListener(this);

		fwdButton = new JButton(">>");
		fwdButton.setActionCommand(CMD_FWD);
		fwdButton.addActionListener(this);

		stateLabel = new JLabel("state: Stopped");

		// Put it all together

		Container contents = getContentPane();
		contents.add(displayPanel, BorderLayout.NORTH);
		JPanel p = new JPanel();
		p.add(revButton);
		p.add(stopButton);
		p.add(fwdButton);
		contents.add(p, BorderLayout.WEST);
		contents.add(stateLabel, BorderLayout.CENTER);
		contents.add(ndtSlider, BorderLayout.SOUTH);

		thread = new Thread(this);
		thread.start();
	}

	public void run() {
		try {
			while (true) {
				runLock.grab();
				displayLock.grab();
				displayLock.disable();
				s.step(direction, ndt);
				displayPanel.repaint();
			}
		} catch (Exception e) {
			System.out.print("run(): ");
			System.out.println(e);
		}
	}

	public void actionPerformed(ActionEvent e) {
		String cmd = e.getActionCommand();
		if (cmd.equals(CMD_STOP)) {
			runLock.disable();
			stateLabel.setText("Stopped");
		}
		else if (cmd.equals(CMD_FWD)) {
			direction = true;
			runLock.enable();
			stateLabel.setText("Running forwards");
		}
		else if (cmd.equals(CMD_REV)) {
			direction = false;
			runLock.enable();
			stateLabel.setText("Running in reverse");
		}
	}

	public void stateChanged(ChangeEvent e) {
		ndt = ndtSlider.getValue();
	}

	class Lock extends Object {
		boolean enabled = false;
		synchronized public void grab() throws InterruptedException {
			while (!enabled) {
				wait();
			}
		}
		synchronized public void enable() {
			enabled = true;
			notifyAll();
		}
		public void disable() {
			enabled = false;
		}
	}
}