import java.awt.Dimension;
import java.awt.FlowLayout;
import java.awt.Toolkit;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.ArrayList;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JTextField;


public class Sarmiento_Josephus {
    JFrame frame;
    JButton solveButton;
    JTextField numTF, intervTF;
    JLabel numLabel, intervLabel;


    public static void main(String[] args) {
        Sarmiento_Josephus app = new Sarmiento_Josephus();

        app.initialize();
    }

    public void buttonActionPerformed(ActionEvent evt) {
        int num, interv, survivor;
        num = Integer.parseInt(numTF.getText());
        interv = Integer.parseInt(intervTF.getText());
        survivor = findSurvivor(num, interv);


        JOptionPane.showMessageDialog(frame, "The survivor is: " + survivor, "Survivor", JOptionPane.PLAIN_MESSAGE);
    }

    public int findSurvivor(int num, int interv) {
        ArrayList<Integer> list = new ArrayList<Integer>();
        int current1 = interv, current2;

        for(int i = 1; i <= num; i++)
            list.add(i);

        while(list.size() > 0) {
            int burier;
            current1 = checkCurrent(current1, list.size(), interv);
            list.remove(current1-1);
            current2 = current1;
            current2 += interv;
            current2 = checkCurrent(current2, list.size(), interv);
            burier = list.get(current2-1);
            list.add(current1-1, burier);
            current1 += interv;
        }

        return list.get(0);
    }

    public int checkCurrent(int current, int size, int interv) {
        while(current > size) {
            current -= size;
        }

        return current;
    }

    public void initialize() {
        //initialize the components
        frame = new JFrame("Franz Sarmiento's Endterm Project");
        solveButton = new JButton("Solve!");
        numLabel = new JLabel("Enter the number of people:");
        numTF = new JTextField();
        intervLabel = new JLabel("Enter the interval:");
        intervTF = new JTextField();

        //set attributes of the GUI
        frame.setPreferredSize(new Dimension(640, 480));
        frame.setResizable(false);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.getContentPane().setLayout(new FlowLayout());
        numTF.setPreferredSize(new Dimension(50, 20));
        intervTF.setPreferredSize(new Dimension(50, 20));

        //add the event listener
        solveButton.addActionListener(
                new ActionListener() {
                    public void actionPerformed(ActionEvent evt) {
                        buttonActionPerformed(evt);
                    }
                }
        );

        //set frame to start in the center
        Dimension dim = Toolkit.getDefaultToolkit().getScreenSize();
        int w = frame.getSize().width;
        int h = frame.getSize().height;
        int x = (dim.width-w)/4;
        int y = (dim.height-h)/4;
        frame.setLocation(x, y);

        //add the components to the pane

        frame.getContentPane().add(numLabel);
        frame.getContentPane().add(numTF);
        frame.getContentPane().add(intervLabel);
        frame.getContentPane().add(intervTF);
        frame.getContentPane().add(solveButton);

        //finalize the GUI
        frame.pack();
        frame.setVisible(true);
    }
}