// Harness for doing the various random applets for MAS964 ps9

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

public class RandomApplet extends DoubleBufferApplet implements Runnable {
  protected Thread animThread;
  int frameDelay = 25;
  int frameNumber = 0;

  FixedNumberFont font;
  int fontY;
  
  boolean redrawLeft, redrawRight;
  int leftNumber, rightNumber;
  ACG rightGen, leftGen;

  static final int maxUpdateFrequency = 400;
  int leftUpdateFrequency = 50;
  int rightUpdateFrequency = 50;

  public void init() {
    this.setBackground(Color.white);
    this.setForeground(Color.black);
    update(getGraphics());
    super.init();

    String frameDelayString = getParameter("frameDelay");
    try {
      if (frameDelayString != null)
        frameDelay = Integer.parseInt(frameDelayString);
    } catch (Exception e) {}

    font = new FixedNumberFont(this);
    redrawLeft = false;
    redrawRight = false;

    // create two random number generators
    int rightSeed, leftSeed;
    int t = (int)System.currentTimeMillis();
    rightSeed = Math.abs(t*t);
    leftSeed = Math.abs(t*t*t);
    rightGen = new ACG(24, 55, rightSeed);
    leftGen = new ACG(11, 37, leftSeed);
  }

  // redraw left and right sides.
  // synchronized with keyDown()
  public synchronized void redrawImage() {
    fontY = (imageBufferSize.height - font.getHeight()) / 2;
    if (redrawLeft)
      drawLeft();
    if (redrawRight)
      drawRight();
    repaint();
  }

  // draw the left side font
  public void drawLeft() {
    Graphics g = imageBuffer.getGraphics();
    font.drawNumber(g, leftNumber, 0, fontY);
  }

  // draw the right side font
  public void drawRight() {
    Graphics g = imageBuffer.getGraphics();
    font.drawNumber(g, rightNumber, imageBufferSize.width - font.getWidth(), fontY);
  }

  // update left and right as appropriate
  public void run() {
    while (Thread.currentThread() == animThread) {
      doFrame();
      frameNumber++;
      try {
        Thread.sleep(frameDelay);
      } catch (InterruptedException ex) {
        System.out.println("Sleep Interrupted??");
      }
    }
  }

  public void start() {
    super.start();
    animThread = new Thread(this);
    animThread.start();
  }

  public void stop() {
    animThread = null;
    super.stop();
  }

  public void doFrame() {
    if (frameNumber % leftUpdateFrequency == 0)
      updateLeft();
    if (frameNumber % rightUpdateFrequency == 0)
      updateRight();
    
    if (redrawLeft || redrawRight)
      redrawImage();
  }
      
  // generate a new number for left
  public void updateLeft() {
    redrawLeft = true;
    leftNumber = leftGen.next() & 0xff;
  }

  // generate a new number for right
  public void updateRight() {
    redrawRight = true;
    rightNumber = rightGen.next() & 0xff;
  }

  // start/stop threads. Synchronized with redrawImage(), to prevent
  // this thread from killing the redraw while it's happening
  public synchronized boolean keyDown(Event e, int key) {
    if ((char)key == ' ') {
      if (animThread == null) {
        animThread = new Thread(this);
        animThread.start();
      } else {
        animThread = null;
      }
    }
    return true;
  }

  // mouse events reset the frequency of left and right
  // on mouse down, we also muck with the generators a bit
  public boolean mouseDown(Event e, int x, int y) {
    recalcFrequency(x, y);

    if (x < imageBufferSize.width / 2)
      leftGen.push((int)(e.when * y));
    else
      rightGen.push((int)(e.when * y));

    return true;
  }

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

  public boolean mouseUp(Event e, int x, int y) {
    recalcFrequency(x, y);
    return true;
  }

  // frequency varies as the square of the distance from the
  // mouse click to the center row.
  public void recalcFrequency(int x, int y) {
    float where = (float)y / imageBufferSize.height;
    if (where < 0.5)
      where = (1 - where);
    where = 1 - where * 2;
    int newFreq = (int)(where * where * maxUpdateFrequency) + 1;
    if (x < imageBufferSize.width / 2)
      leftUpdateFrequency = newFreq;
    else
      rightUpdateFrequency = newFreq;
  }
}