// This is the towers of Hanoi problem
// using recursion

import java.awt.Toolkit;
import java.awt.Graphics;
import java.awt.Color;
import java.awt.FlowLayout;
import java.awt.Container;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.Stack;
import java.util.EmptyStackException;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextField;

/**
 * A helper class to hold the disks
 */
class TowerStack extends Stack<Integer> {
    
    public void display(int x, int y, Graphics g) {
        for(int i = 0; i < size(); i++) {
            int width = 20*((Integer)get(i)).intValue();
            g.setColor(Color.red);
            g.fillRoundRect(x-width/2,y-10*(i+1),width+1,10,10,10);
            g.setColor(Color.black);
            g.drawRoundRect(x-width/2,y-10*(i+1),width+1,10,10,10);
        } // end for
    } // end display
    
} // end TowerStack


/**
 * This program show the moves of the Towers of Hanoi puzzle
 * @author Bill Kraynek
 */
public class TowersOfHanoi {
    JFrame theFrame;
    JLabel promptN;
    int n;
    int moves;
    JTextField inputN;
    JPanel one;
    JScrollPane inputPane;
    final int WIDTH = 650;
    final int HEIGHT = 500;
    final int XLEFT = 110;
    final int XMIDDLE = 320;
    final int XRIGHT = 520;
    final int YDOWN = 280;
    final int YUP = 170;
    final int WIDTHINC = 110;
    final int HEIGHTINC = 220;
    Graphics g;
    TowerStack peg1 = new TowerStack();
    TowerStack peg2 = new TowerStack();
    TowerStack peg3 = new TowerStack();
    
    public TowersOfHanoi() {
        theFrame = new JFrame("Towers of Hanoi");
        Toolkit tk = Toolkit.getDefaultToolkit();
        theFrame.setSize(WIDTH,HEIGHT);
        theFrame.setLocation(tk.getScreenSize().width/4,tk.getScreenSize().height/4);
        theFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        Container content = theFrame.getContentPane();
        content.setBackground(Color.white);
        content.setLayout(new FlowLayout(FlowLayout.CENTER,10,10));
        one = new JPanel();
        promptN= new JLabel("Enter the number of disks (1-10) > ");
        one.add(promptN);
        inputN= new JTextField(5);
        inputN.addActionListener(new inputNAction());
        one.add(inputN);
        one.setBackground(Color.orange);
        inputPane = new JScrollPane(one);
        content.add(inputPane);
        theFrame.setVisible(true);
    }// end constructor
    
    public static void main(String[] args) {
        new TowersOfHanoi();
    } // end main
    
    public void moveDisks(int n, TowerStack start, TowerStack finish, TowerStack aux){
        if ( n == 0 ) return;
        moveDisks(n-1,start,aux,finish);
        finish.push(start.pop());
        moves++;
        drawTowers(g);
        moveDisks(n-1,aux,finish,start);
    } // end moveDisks
    
    public void drawLines(Graphics g) {
        g.drawLine(XLEFT,YDOWN,XLEFT,YUP);
        g.drawLine(XMIDDLE,YDOWN,XMIDDLE,YUP);
        g.drawLine(XRIGHT,YDOWN,XRIGHT,YUP);
        g.drawLine(10,YDOWN,HEIGHTINC,YDOWN);
        g.drawLine(10+WIDTHINC,YDOWN,2*HEIGHTINC,YDOWN);
        g.drawLine(10+2*WIDTHINC,YDOWN,3*HEIGHTINC,YDOWN);
    }
    
    public void drawTowers(Graphics g) {
        g.setColor(Color.white);
        g.fillRect(0,75,WIDTH,HEIGHT-75);
        g.setColor(Color.red);
        drawLines(g);
        peg1.display(XLEFT,YDOWN,g);
        peg2.display(XMIDDLE,YDOWN,g);
        peg3.display(XRIGHT,YDOWN,g);
        try{Thread.sleep(500);}catch(Exception e){}
    } // end drawTowers
    
    class inputNAction implements ActionListener {
        
        public void actionPerformed(ActionEvent A){
            try{
                n=Integer.parseInt(inputN.getText());
            } catch(NumberFormatException e){
                inputN.setText("1 to 10");
                inputN.selectAll();
                return;
            } // end try/catch
            if( n < 1 || n > 10 ){
                inputN.setText("1 to 10");
                inputN.selectAll();
                return;
            }
            inputN.setText("");
            moves = 0;
            peg1.setSize(0);
            for(int i = n; i > 0; i--) {
                peg1.push(i);
            }
            peg2.setSize(0);
            peg3.setSize(0);
            g = theFrame.getGraphics();
            drawTowers(g);
            moveDisks(n,peg1,peg2,peg3);
            g.drawString("___________________________"+n+" disks took "+moves+" move"+(moves>1?"s":"")+"___________________________",100,100);
        } // end actionPerformed
        
    } // end inputNAction
    
    
} // end TowersOfHanoi