//------------
// Introduction to Programming Using Java: An Object-Oriented Approach
//Arnow/Weiss
//------------
import java.util.*;
import java.awt.*;
import java.awt.event.*;
import java.applet.*;

class TowerDisplay extends Canvas {
    public TowerDisplay() {
        c = new Color[10];
        c[0] = new Color(255,0,0);
        c[1] = new Color(0,255,0);
        c[2] = new Color(0,0,255);
        c[3] = new Color(255,255,0);
        c[4] = new Color(255,0,255);
        c[5] = new Color(0,255,255);
        c[6] = new Color(44,150,44);
        c[7] = new Color(44,44,150);
        c[8] = new Color(150,150,44);
        c[9] = new Color(150,44,150);
    }
    public void setup(int nDisks, int source) {
        if (nDisks>9)
           nDisks = 9;
        tower = new String[4];
        tower[1] = "123456789".substring(0,nDisks);
        tower[2] = "";
        tower[3] = "";
        this.nDisks = nDisks;
        myWidth = this.getSize().width - 2*borderSize;
        myHeight = this.getSize().height - 2*borderSize;
        smallestDiskWidth = (myWidth/4) / nDisks;
        diskWidth = nDisks*smallestDiskWidth;
        interDiskWidth = diskWidth/4;
               diskHeight = 10;
               towerHeight = (nDisks+1) * diskHeight;
               lineLeft = borderSize + interDiskWidth;
               lineBot  = myHeight - (myHeight-
                                      towerHeight)/2;
               lineWidth = 3*diskWidth + 2*interDiskWidth;
               lineRight = lineLeft+lineWidth;
               towerLeft = new int[4];
               towerLeft[1] = lineLeft + diskWidth/2;
               towerLeft[2] = towerLeft[1] + diskWidth/2
                            + interDiskWidth + diskWidth/2;
               towerLeft[3] = towerLeft[2] + diskWidth/2
                            + interDiskWidth + diskWidth/2;
               paint(this.getGraphics());
               delay(1000);
           }
           public void setDelay(int d) {
               sdelay = d;
           }
           public void displayMove(int from, int to) {
               Graphics g = this.getGraphics();
               int fromLast = tower[from].length()-1;
               Color   c = getDiskColor(from,fromLast);
               tower[to] = tower[to].concat(tower[from].
                                      substring(fromLast));
               tower[from] = tower[from].
                                     substring(0,fromLast);
               paintLowerBackground(g);
               g.setColor(c);
               g.setFont(new 
                           Font("Helvetica",Font.BOLD,18));
               g.drawString("Move from "+from+" to "+to, 
                             lineLeft,myHeight - (myHeight-
                             towerHeight)/4);
        delay(sdelay);
        paint(g);
        delay(sdelay/3);
    }
    public void update(Graphics g) {
        paint(g);
    }
    public void paint(Graphics g) {
        paintBackground(g);
        paintBorder(g);
        g.setColor(new Color(0,0,0));
        if (tower==null)
           return;
        g.drawLine(lineLeft,lineBot,lineRight,lineBot);
        paintTower(g,1);
        paintTower(g,2);
        paintTower(g,3);
    }
    private void paintTower(Graphics g, int whichTower) {
        int j;
        String s = tower[whichTower];
        g.setColor(new Color(0,0,0));
        g.drawLine(towerLeft[whichTower],lineBot,
                towerLeft[whichTower],lineBot-towerHeight);
        for (int i=0;i<s.length();i++) {
           j = nDisks - Integer.parseInt(s.substring(i, 
                                         i+1));
                   g.setColor(getDiskColor(whichTower,i));
                   int  jWidth = (1+j)*smallestDiskWidth;
                   int  jLeft = towerLeft[whichTower] - 
                                                  jWidth/2;
                   int  jBot = lineBot - diskHeight - 
                                              i*diskHeight;
                   g.fill3DRect(jLeft, jBot, jWidth, 
                                         diskHeight, true);
           }
        }
           private void paintLowerBackground(Graphics g) {
               g.setColor(new Color(255,255,255));
               g.fillRect(lineLeft-2, lineBot+4, 
                     lineWidth+4,(myHeight-towerHeight)/4);
           }
           private void paintBackground(Graphics g) {
               g.setColor(new Color(255,255,255));
               g.fillRect(5,5,this.getSize().width-
                            10,this.getSize().height - 10);
           }
           private void paintBorder(Graphics g) {
               g.setColor(new Color(0,0,0));
               g.fillRect(0,0,this.getSize().
                          width,borderSize);
               g.fillRect(0,this.getSize().height-
                          borderSize,
                          this.getSize().width,borderSize);
               g.fillRect(0,0,borderSize,this.
                          getSize().height);
               g.fillRect(this.getSize().width-
                          borderSize,0, borderSize,this.
                          getSize().height);
           }
           private Color getDiskColor(int whichTower, 
                                                   int n) {
           String s = tower[whichTower];
           int j = nDisks - 
                      Integer.parseInt(s.substring(n,n+1));
           return c[j%10];
    }
    private void delay(int n) {
        try {
           Thread.sleep(n);
        } catch(Exception e) {}
    }
    private final   int    borderSize = 5;
    private    int         sdelay=100;
    private    int         nDisks;
    private    String[]    tower = null;
    private    Color[]     c;
    private    int         myHeight;
    private    int         myWidth;
    private    int         diskWidth;
    private    int         smallestDiskWidth;
    private    int         interDiskWidth;
    private    int         diskHeight;
    private    int         towerHeight;
    private    int         lineBot;
    private    int         lineLeft;
    private    int         lineRight;
    private    int         lineWidth;
    private int[ ] towerLeft;
}