import java.applet.*;
import java.awt.*;

public class CliffSolution extends Applet 
{

    int wins = 0;
    int losses = 0;
    int position = 0;
    int numRuns = 0;
    int total = 0;
    int runCount = -1;
    String numer, denom;
    int num = 0, den = 0;
    boolean wait = false;
    int[] arrPositionCount = new int[30];
    int[] arrPositionSmallCount = new int[30];
    Image back, offscreenImage;
    Graphics offscreenGraphics;
    Font f;
    Thread runner;

    Button start100;
    Button start10000;
    Button start1000000;

    TextField numerator;
    TextField denominator;

    public void init()
    {
	add(new Label("Homer will step toward the edge"));
	numerator = new TextField("1", 3);
	add(numerator);
	add(new Label("out of"));
	denominator = new TextField("3", 3);
	add(denominator);
	add(new Label("times."));
	start100 = new Button("100 Runs");
	add(start100);
	start10000 = new Button("10,000 Runs");
	add(start10000);
	start1000000 = new Button("1,000,000 Runs");
	add(start1000000);

        back = getImage(getCodeBase(), "back.gif");
        offscreenImage = createImage(size().width, size().height);
        offscreenGraphics = offscreenImage.getGraphics();
        repaint();
    }

    public void paint(Graphics g)
    {
	  offscreenGraphics.drawImage(back, 0, 0, this);
        offscreenGraphics.setFont(new Font("TimesRoman", 1, 12));
        offscreenGraphics.drawString("Wins: " + wins, 5, 70);
	  offscreenGraphics.drawString("Losses: " + losses, 5, 85);
	if (runCount < 0)
	{
	  for (int i = 0; i < 30; i++)
	  {
	     if (wins == 0 && losses == 0)
			total = 1;			//so we have no division by zero below
	     else
			total = wins + losses;
	     offscreenGraphics.drawString(i + "", 30, 120 + 15*i);
	     offscreenGraphics.drawString("" + arrPositionCount[i], 70, 120 + 15*i);
	     offscreenGraphics.drawString("" + (double)arrPositionCount[i]/(total), 150, 120 + 15*i);
	     offscreenGraphics.drawString("" + arrPositionSmallCount[i], 230, 120 + 15*i); 
	     offscreenGraphics.drawString("" + (double)arrPositionSmallCount[i]/(total), 310, 120 + 15*i); 
	  }
	}
	  else
	  {
	     f = new Font("TimesRoman", 1, 20);
	     offscreenGraphics.setFont(f);
	     offscreenGraphics.setColor(Color.red);
	     offscreenGraphics.drawString("Please Wait - Runs Calculated: " + runCount, 40, 103);
	     offscreenGraphics.setColor(Color.black);
	     wait = false;
	  }
	g.drawImage(offscreenImage,0,0,this);
    }

    public void update(Graphics g) 
    {
	paint(g); 
    }

    public boolean action(Event event, Object obj)
    {

        if(event.target == start100)
	  {

		setProbability();

		for (int i = 0; i < 30; i++)
		{
		    arrPositionSmallCount[i] = 0;
		    arrPositionCount[i] = 0;
		}
		wins = 0;
		losses = 0;
		numRuns = 100;
		run100();
	  }
        if(event.target == start10000)
	  {
		setProbability();

		for (int i = 0; i < 30; i++)
		{
		    arrPositionSmallCount[i] = 0;
		    arrPositionCount[i] = 0;
		}
		wins = 0;
		losses = 0;
		numRuns = 10000;
		run100();
	    }	
        if(event.target == start1000000)
	  {
		setProbability();

		for (int i = 0; i < 30; i++)  //change to 30 steps
		{
		    arrPositionSmallCount[i] = 0;
		    arrPositionCount[i] = 0;
		}
		wins = 0;
		losses = 0;
		numRuns = 1000000;
		wait = true;
		update(this.getGraphics());
		System.out.println("Before run100 call");
		run100();
		System.out.println("After run100 call");
	    }	

        return true;
    }

    public void setProbability()
    {
	  	numer = numerator.getText();
		denom = denominator.getText();
      	try {
         	num = Integer.parseInt(numer.trim());
      	} catch (NumberFormatException nfe) {
         	System.out.println("NumberFormatException: " + nfe.getMessage());
      	}
      	try {
         	den = Integer.parseInt(denom.trim());
      	} catch (NumberFormatException nfe) {
         	System.out.println("NumberFormatException: " + nfe.getMessage());
      	}
    }

    public void run100()
    {
	position = 0;
	boolean moveForward;
	boolean[] arrOfPosition = new boolean[30];
	arrOfPosition[0] = true;
	wins = 0;

	update(this.getGraphics());
	for (int i = 0; i < numRuns; i++)
	{
	    boolean keepGoing = true;
	    position = 0;
	    for (int k = 1; k < 30; k++)
	        arrOfPosition[k] = false;

	    do 
	    {
		  if (i % 50000 == 0)
		  {
			runCount = i;
			update(this.getGraphics());
		  }
	        moveForward = move();
	        if (moveForward)
		    position--;
		  else
		    position++;
		  
		  if (position >= 0 && position <= 29)
		    arrOfPosition[position] = true;

		  if (position < 0)
		  {
		    losses++;
		    for (int j = 0; j < 30; j++)
			 if (arrOfPosition[j])
				arrPositionCount[j]++;
		    for (int j = 29; keepGoing; j--)
			 if (arrOfPosition[j])
			 {
				arrPositionSmallCount[j]++;
				keepGoing = false;
			 }
		  }
		  if (position > 29)
		    wins++;
	    }
	    while (position >= 0 && position <=29);
	}
	wait = false;
	runCount = -1;
	repaint();
    }

    public boolean move()
    {
	boolean moveForward;
      int i = (int)(Math.random() * den);
            
	if (i < num)
          moveForward = true;
	else
          moveForward = false;
	return moveForward;
    }


}