// file:    DESCapplet.java
// author:  Robert Keller
// purpose: Applet for drawing a Double-Ended Spam-Cruncher in action.

/**  
 * DESCapplet.java
 * @version 1
 * @author  Robert M. Keller
 * $Id: DESCapplet.java,v 1.16 2002/11/12 03:35:50 keller Exp $
 */

import java.applet.*;           // applet classes
import java.awt.*;              // Abstract Window Toolkit classes

/**
 * Applet for drawing DESC
 */ 

public class DESCapplet extends Applet implements Runnable
  {
  Label banner = new Label("DESC Applet ");

  Color backgroundColor = Color.white,
        foregroundColor = Color.black;

  Font mainBold = new Font("Helvetica", Font.BOLD, 18);

  static int delay[] = {25, 50, 100, 200, 400, 800, 1600};	// delay values

  static int currentDelay = 50;					// delay

  int xGridOffset = 70;		// offset for the grid from upper left corner
  int yGridOffset = 70;	
  int gridSize = 20;		// size of one square of the grid
  int xString = 50;		// location of String indicating no. of steps
  int yString = 50;

  String stepsTakenString = " steps taken"; // suffix of string for steps
  int stepsTaken;		// number of steps taken by the DESC

  DESC desc = null;

  Thread myThread;

  Image image;
  
  Graphics graphics;            // graphics buffer

  Choice sampleChoice;          // choice menu for samples

  Choice delayChoice;           // choice menu for delay

  Sample sample[];		// array of samples

  AppletGrid grid;		// Grid extended for this applet

  /**
   *   Initialize the applet.
   */

  public void init()
    {
    setBackground(backgroundColor);             // set the background color
    image = createImage(size().width, size().height);   
    graphics = image.getGraphics();             // make a graphics buffer
    graphics.setFont(mainBold);

    banner.setFont(mainBold);
    add(banner);

    // Make Choice menu for selecting example.

    sampleChoice = new Choice();
    sampleChoice.setFont(mainBold);
    add(sampleChoice);
    sample = Sample.makeSamples();
    setSamples(sampleChoice, sample);

    // Make Choice menu for selecting delay.

    delayChoice = new Choice();
    delayChoice.setFont(mainBold);
    add(delayChoice);
    setDelays(delayChoice, delay);
    }


  /**
   * Act on a choice from a menu.
   */

  public boolean action(Event event, Object arg)
    {
    if( event.target == sampleChoice )
      {
      // choose the input sample based on its index in the menu
      int index = sampleChoice.getSelectedIndex();
      if( index > 0 )
        {
        setInput(index-1);
        stepsTaken = 0;
        }
      }
    else if( event.target == delayChoice )
      {
      // choose a delay value based on its index in the menu
      int index = delayChoice.getSelectedIndex();
      if( index > 0 )
        {
        currentDelay = delay[index-1];
        }
      }
    return super.action(event, arg);
    }


  /**
   * Act on a mouseDown event.
   */

  public boolean mouseDown(Event e, int x, int y)
    {
    int row = (y-yGridOffset)/gridSize;
    int col = (x-xGridOffset)/gridSize;
    if( grid.inRange(row, col) )
      {
      if( grid.hasSpam(row, col) )
	{
	grid.setBlank(row, col);
	}
      else if( grid.isBlank(row, col) )
	{
	grid.setSpam(row, col);
	}
      }
    return true;
    }


  /**
   * Act on a mouseDrag event.
   */

  public boolean mouseDrag(Event e, int x, int y)
    {
    return mouseDown(e, x, y);
    }


  /**
   * Set the sample titles in a choice menu.
   */

  void setSamples(Choice sampleChoice, Sample sample[])
    {
    sampleChoice.addItem("Choose Sample");

    int n = sample.length;

    for( int j = 1; j <= n; j++ )
      {
      sampleChoice.addItem(sample[j-1].getTitle());
      }
    }


  /**
   * Set the delay values in a choice menu.
   */

  void setDelays(Choice delayChoice, int delay[])
    {
    delayChoice.addItem("Choose Delay (ms)");

    for( int j = 1; j <= delay.length; j++ )
      {
      delayChoice.addItem("" + delay[j-1]);
      }
    }


  /**
   *   start the applet
   */
  public void start()
    {
    if( myThread == null )
      {
      myThread = new Thread(this);
      myThread.start();
      }
    }

  /**
   *   stop the applet
   */
  public void stop()
    {
    myThread.stop();
    }

  void drawSteps(int steps)
    {
    graphics.setColor(Color.black);
    graphics.drawString(stepsTaken + stepsTakenString, xString, yString);
    }


  /**
   *   run the applet
   */

  public void run()
    {
    while( true )
      {
      if( desc != null )
        {
	drawGrid();
        if( desc.moveTowardSpam() )
          {
          stepsTaken++;
          }
        }
      try
	{
	myThread.sleep(currentDelay);
	}
      catch( Exception e )
	{
	}
      }
    }


  /**
   *   update is implicitly called by repaint()
   *   It calls paint(Graphics)
   */

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


  /**
   *   paint(Graphics) is is called by update(Graphics)
   */

  public void paint(Graphics g)
    {
    g.drawImage(image, 0, 0, null);
    }

  void drawGrid()
    {
    graphics.setColor(backgroundColor);
    graphics.fillRect(0, 0, size().width, size().height);
    graphics.setColor(foregroundColor);

    grid.draw(graphics, xGridOffset, yGridOffset, gridSize);
    drawSteps(stepsTaken);
    repaint();
    }


  void setInput(int index)
    {
    grid = new AppletGrid(sample[index]);
    desc = new DESC(grid, DESC.start0, DESC.start1);
    }


  } // DESCapplet