/**
 * Josephus -- 
 * A class to graphically depict a Josephus selection
 * 
 * @author rpj
 * @version 28ii08
 */



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

public class Josephus extends Applet {
    // defaults
     private static final int SIZE = 8;  // how many people
     private static final int NTH = 3;   // eliminate every Nth person
     // instance variables
     int size = SIZE;
     int nth = NTH;
     TextField setSize = new TextField("Enter number of soldiers here");
     TextField setNth = new TextField("I will kill every nth soldier.  Enter n here");
     TextField person;
     CircularList<TextField> people;
     /** button to control the applet: */
     Button pickSurvivorBtn = new Button("pickSurvivor");
     public void init() {
         people = new CircularList<TextField>();
         setLayout(new FlowLayout());
         add(pickSurvivorBtn);
         setSize.setEditable(true);
         setNth.setEditable(true);
         add(setSize);
         add(setNth);
         pickSurvivorBtn.addActionListener(new ActionListener() {
             public void actionPerformed(ActionEvent buttonPress) {  
                 try {
                     size = new Integer(setSize.getText());
                     nth = new Integer(setNth.getText());
                 }
                 catch (NumberFormatException nfe) {
                 // revert to defaults
                 }
                 for (int i=0; i<size; i++) {
                     person  = new TextField("Number "+i);
                     person.setFont(new Font("TimesRoman", Font.BOLD, 24));
                     person.setBackground(Color.cyan);
                     add(person);
                     people.add(person);
                 }
                 validate();
                 SwingUtilities.invokeLater(new Runnable() {
                         public void run() {
                             doIt();
                         }
                     });
             }
        });
     }
    public void doIt() {
        pickSurvivorBtn.setEnabled(false);
        for (int i=0; i<size-1; i++) {
            for (int j=1; j<nth; j++) {
                (people.peek()).setBackground(Color.white);
                pause(500);
                (people.peek()).setBackground(Color.cyan);
                people.rotate();
            }
            (people.peek()).setBackground(Color.red);
            pause(2000);
            remove(people.peek());
            people.removeFromHead();
        }
        setNth.setText("Survivor is "+people.peek().getText());
        pause(10000);
        setSize.setText("Enter number of soldiers here");
        setNth.setText("I will kill every nth soldier.  Enter n here"); 
        remove(people.peek());
        people = new CircularList<TextField>();
        pickSurvivorBtn.setEnabled(true); 
    }
    public void pause(int time) {
        try { Thread.sleep(time); }
        catch(InterruptedException ignored) {}
    }
}