import java.applet.*;
import java.awt.*;
import java.awt.event.*;
import java.util.*;

/* When the user clicks on the Go button, any text in the
  textarea is processed.
  Each line of text is assumed to represent a command to
  draw a line on the LineCanvas component of the applet.

  Example input:
  LINE (100,100) (500,150)
  LINE (100,300) (500,250)
  LINE 100 100 100 300
*/

public class LineApplet extends Applet
    implements ActionListener {

    TextArea ta;
    LineCanvas theLineCanvas;
    Button goButton;

    int x1, y1, x2, y2;

    public void init() {
	setLayout(new BorderLayout());
	ta = new TextArea(5,20);
	theLineCanvas = new LineCanvas();
	goButton = new Button("Go");
	theLineCanvas.setSize(300,200);
	theLineCanvas.setBackground(Color.yellow);
	add(ta, BorderLayout.NORTH);
	add(theLineCanvas, BorderLayout.CENTER);
	add(goButton, BorderLayout.SOUTH);
	goButton.addActionListener(this);
    }

    public void actionPerformed(ActionEvent e) {
	if (e.getSource() == goButton)  {
	    theLineCanvas.clear();
	    StringTokenizer lines = new StringTokenizer(ta.getText(), "\n");
	    while (lines.hasMoreTokens()) {
		String line = lines.nextToken();

		try {
		    StringTokenizer lt = new StringTokenizer(line, "() ,;");
		    String command = lt.nextToken();
		    if (command.equals("CLEAR")) {
			theLineCanvas.clear();
			continue;
		    }
		    if (! (command.equals("LINE"))) {
			error("Unknown command: " + command);
			continue;
		    }
		    if (isInt(lt.nextToken())) { x1 = inputInt; }
		    else continue;
		    if (isInt(lt.nextToken())) { y1 = inputInt; }
		    else continue;
		    if (isInt(lt.nextToken())) { x2 = inputInt; }
		    else continue;
		    if (isInt(lt.nextToken())) { y2 = inputInt; }
		    else continue;
		    theLineCanvas.addLine(x1, y1, x2, y2);
		}
		catch (Exception exc) {
		    error("LineApplet expected a proper LINE command but got: " + line);
		}
	    }
	}

    }

    int inputInt;
    boolean isInt(String token) {
	boolean returnVal = true;
	try {
	    inputInt = (new Integer(token)).intValue();
	}
	catch(NumberFormatException nfe) {
	    error("LineApplet expected an integer but found: " + token);
	    returnVal = false;
	}
	return returnVal;
    }

    void error(String msg) {
	theLineCanvas.setString(msg);
	System.out.println(msg);
    }
}