import java.applet.*;
import java.awt.*;
import java.awt.image.*;
import java.lang.Math;
import java.awt.event.*;
import java.net.*;
import java.util.*;
import java.lang.*;

// use the old event model to be compatible with Java 1.1.5

public class SatWorks extends Applet implements Runnable,
  ActionListener, ItemListener, AdjustmentListener,
  KeyListener, MouseListener, MouseMotionListener {

  Button button;
  Checkbox checkbox;
  Checkbox leoCheck, geoCheck;
  Label label;
  Choice choice;
  Graphics gb;
  Scrollbar scrollbar;
  Image buffer;
  Image satImage, laloImage, worldImage;
  RotateGlobe rg;
  String param;
  int longi = 90;
  double Altitude = 5.;
  boolean isRotating = true;
  int R = 90;
  double satAng = 0.;
  double declination = 15. * .0174533;
  double swathWidth = 10.;
  int ratioMax = 23;  // ratio of sat orbits to earth rotations
  int spotSize = 3;
  int numSpots = 5;


  public void init() {

    laloImage = loadImage("latlon.gif");
    worldImage = loadImage("world.gif");
    satImage = loadImage("satellite.jpg");

    rg = new RotateGlobe(laloImage, worldImage,R);
    rg.setSwath(declination, swathWidth, spotSize, numSpots);
    buffer = createImage(500,500);
    gb = buffer.getGraphics();

    // defining widgets
    button = new Button("Button");
    button.addActionListener(this);

    checkbox = new Checkbox("checkbox");
    checkbox.addItemListener(this);

    choice = new Choice();
    choice.add("one");
    choice.add("two");
    choice.addItemListener(this);

    // orientation, initial value, size of bubble, minimum, maximum
    scrollbar = new Scrollbar(Scrollbar.HORIZONTAL, 50, 10, 0, 110);
    scrollbar.addAdjustmentListener(this);

    label = new Label("The Label",Label.CENTER);


    // parsing parameters
    param = getParameter("parameter");
    if (param != null) {
      StringTokenizer st = new StringTokenizer(param, ",");
      int n = st.countTokens();
      for (int i=0; i<n; i++) {
        System.out.println("####  Parsing parameter = "+st.nextToken().trim());
      }
    }

    add(button);
    //add(checkbox);
    //add(choice);
    //add(scrollbar);
    //add(label);

    //making numbers
    // int value = Integer.parseInt(param.trim());
    // int value = Integer.valueOf(param.trim()).intValue();
    // double value = Double.valueOf(param.trim()).doubleValue();


    //image = getImage(getDocumentBase(),"image.gif");
    //or use the loadImage("image.gif") below to load from JAR file or URL...

    //URL u = new URL(getDocumentBase(), "filename");
    //DataInputStream dis;
    //dis = new DataInputStream( new BufferedInputStream(u.openStream());
    //int val = dis.readInt();

  }

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

  public void paint(Graphics g) {
    gb.setColor(Color.black);
    gb.fillRect(0,0,500,500);

    int center = 100 + R;


    gb.drawImage(rg.getImage(longi),100,100,this);

    // increment the satellite position each time this is called
    satAng = satAng + 1.;

    if (satAng >= 180.) satAng = -satAng;

    int ysat = (int) Math.round((R+Altitude)*Math.cos(satAng*.0174533) * Math.cos(declination));
    int xsat = (int) Math.round(ysat*Math.tan(declination));
    double rr = Math.sqrt((double)ysat*ysat + (double)xsat*xsat);

    if ((Math.abs(rr) < R+4) && satAng < 0.0) {
    } else {
      gb.setColor(Color.black);
      gb.drawRect(center+xsat-2,center-ysat-2,5,5);
      gb.setColor(Color.white);
      gb.drawRect(center+xsat-1,center-ysat-1,3,3);
      if (Math.abs(rr) < R) rg.mapSatellite(xsat,ysat);

    }


    gb.setColor(Color.orange);

    g.drawImage(buffer,0,0,this);

  }

  // Listeners
  public void actionPerformed(ActionEvent e) {
    if (e.getSource() == button) {
      isRotating = !isRotating;
      System.out.println("####  The button was pressed");
    }
  }

  public void itemStateChanged(ItemEvent e) {
    if (e.getSource() == checkbox) {
      System.out.println("####  Checkbox set to "+checkbox.getState());
    }

    if (e.getSource() == choice) {
      System.out.println("####  Choice selected "+choice.getSelectedItem());
    }
  }

  public void adjustmentValueChanged(AdjustmentEvent e) {
    if (e.getSource() == scrollbar) {
      System.out.println("####  Scrollbar value = "+scrollbar.getValue());
    }
  }


  // for MouseListener
  public void mouseClicked(MouseEvent e) {
    int mx = e.getX();
    int my = e.getY();
  }
  public void mouseEntered(MouseEvent e) {}
  public void mouseExited(MouseEvent e) {}
  public void mousePressed(MouseEvent e) {}
  public void mouseReleased(MouseEvent e) {}

  //for MouseMotionListener
  public void mouseDragged(MouseEvent e) {}
  public void mouseMoved(MouseEvent e) {}

  //for KeyListener
  public void keyPressed(KeyEvent e) {
    int k = e.getKeyCode();
    char ck = e.getKeyChar();
  }
  public void keyReleased(KeyEvent e) {}
  public void keyTyped(KeyEvent e) {}



  // next, handle running a Thread to automatically repaint
  // the display every "refreshRate" milliseconds
  private Thread animator_thread = null;
  private boolean isRunning;
  int refreshRate = 20;
  int ratio = 0;
  public void start() {
    if (animator_thread == null) {
      isRunning = true;
      animator_thread = new Thread(this);
      animator_thread.start();
    }
  }

  public void stop() {
    if ((animator_thread != null) && animator_thread.isAlive()) {
      isRunning = false;
      animator_thread.stop();
    }
    animator_thread = null;
  }

  public void run () {

    while (isRunning) {
      try { Thread.sleep(refreshRate); 
        if (isRotating) {
          ratio = ratio + 1;
          if (ratio > ratioMax) {
            longi = longi - 1;
            if (longi < 0) longi = 360;
            ratio = 0;
          }
        }
        repaint();
      } catch (Exception re) {
        System.out.println("####  "+re);
      }
    }
  }


  // Utilities for getting images and audio clips from JAR or URL
  public Image loadImage(String name) {
    // first try the URL

    Image img = null;
    URL u = getClass().getResource( (String) name);
    if (u == null) {
      u = getDocumentBase();
      img = getImage(u,name);
    } else {
      img = getImage(u);
    }

		MediaTracker mt = new MediaTracker(this);
		mt.addImage(img, 0);
		try   { mt.waitForAll(); }
		catch ( Exception ex ) {img = null; }
    return img;

  }

}

class RotateGlobe extends Component {
  byte[] pixels, pixWorld;
  int LINES=181;
  int ELEMS=361;
  ColorModel cm;
  int centerlon = 0;
  double declination, swathWidth;
  int spotSize, preferredSpots;
  int R, N;
  int[] line2lat;
  int[][] ele2lon;
  int[] swathX, swathY;
  Image img;
  MemoryImageSource mis = null;
  byte[] pixs;

  // long domain of image 0:360
  public RotateGlobe(Image lalo, Image world, int size) {
    R = size;
    N = 2 * R + 1;
    line2lat = new int[R+1];
    ele2lon = new int[R+1][R+1];

    try {
      PixelGrabber pg = new PixelGrabber(lalo,0,0,ELEMS,LINES,false);
      pg.grabPixels();
      pixels = (byte[]) pg.getPixels();
      cm = pg.getColorModel();
      int stat = pg.status();

      PixelGrabber pgw = new PixelGrabber(world,0,0,ELEMS,LINES,false);
      pgw.grabPixels();
      pixWorld = (byte[]) pgw.getPixels();
      stat = pgw.status();
    } catch (Exception e) {
      System.out.println("####  grabbing:"+e);
    }

    pixs = new byte[N * N];

    // compute lats & lons for quadrant 1 only since others
    // can be derived from that...

    for (int y=0; y<R+1; y++) {
       double lat = Math.asin((double)(R-y)/R);
       line2lat[y] = (int)Math.round(lat/.0174533);
       for (int x=0; x<R+1; x++) {
         double lon = (double)x/(R*Math.cos(lat));
         if (Math.abs(lon) <= 1.0) {
           ele2lon[x][y] = (int) Math.round(Math.asin(lon)/.0174533);
         } else {
           ele2lon[x][y] = -999;
         }
       }
    }

  }

  public void setSwath(double dec, double sw, int spot, int num) {
    declination = dec;
    swathWidth = sw;
    spotSize = spot;
    preferredSpots = num;
  }



  // uncover the observed satellte data
  public void mapSatellite(int x, int y) {
    double xb = x - swathWidth * Math.cos(declination);
    double xe = x + swathWidth * Math.cos(declination);
    double yb = y + swathWidth * Math.sin(declination);
    double ye = y - swathWidth * Math.sin(declination);

    int n = (int) Math.abs(xe - xb);
    if ( Math.abs(ye - yb) > Math.abs(xe -xb) ) n = (int) Math.abs(ye - yb);
    if (n > preferredSpots) n = preferredSpots;

    double xstep = (xe - xb)/n;
    double ystep = (ye - yb)/n;
    double lat, lon;
    int z;

    for (int i=0; i<n+1; i++) {
      

      lat = Math.asin((yb + i*ystep)/(double)R);
      lon = (xb + i * xstep)/(R*Math.cos(lat));

      if (Math.abs(lon) > 1.0) continue;

      lon = Math.asin(lon)/.0174533 + centerlon;
      lat = lat/.0174533;
      if (lon < 0.) lon = 360.+lon;
      if (lon > 360.) lon = lon - 360.;
      z = ELEMS * (int)Math.round(90-lat) + (int)Math.round(lon);
      if (spotSize == 1) {
         pixWorld[z] = pixels[z];

      } else {
        
        int zz;
        for (int m=-spotSize/2; m<spotSize/2; m++) {
          for (int j=-spotSize/2; j<spotSize/2; j++) {
            zz = z + (m * ELEMS) + j;
            if (zz >= 0 && zz < (LINES*ELEMS)) pixWorld[zz] = pixels[zz];
          }
        }
      }

      //System.out.println("####  x="+x+"  y="+y+"  lat="+lat+" lon="+lon);
    }


    /*
    for (int i=z-3; i<z+7; i++) {
      pixWorld[i-ELEMS+1] = pixels[i-ELEMS+1];
      pixWorld[i] = pixels[i];
      pixWorld[i+ELEMS-1] = pixels[i+ELEMS-1];
    }
    */

  }

  public Image getImage(int longitude) {
    int yi, xi;
    int xp, yp;
    int z = 0;
    centerlon = longitude;
    for (int y=0; y<N; y++) {
      if (y > R) {
        yi = N - 1 -y;
        yp = -1;

      } else {
        yi = y;
        yp = +1;
      }

      for (int x=0; x<N; x++) {
        if (x > R) {
          xi = x - R;
          xp = 1;

        } else { 
          xi = R - x;
          xp = -1;
        }

        if (ele2lon[xi][yi] == -999) {
          pixs[z] = (byte)0;  // should be black

        } else {
          try {
          pixs[z] = pixWorld[
             ((longitude+xp*ele2lon[xi][yi]) % ELEMS) + 
               (ELEMS * (90 - yp*line2lat[yi])) ];

          } catch (Exception e2) {
            //System.out.println("####  yp, yi, l2l = "+yp+"  "+yi+" "+line2lat[yi]);
          }
        }

        z = z + 1;

      }
    }

    if (mis == null) {
      mis = new MemoryImageSource(N,N,cm,pixs,0,N);
      mis.setAnimated(true);
      img = createImage(mis);
    } else {
      mis.newPixels(0,0,N,N,false);
    }

    return img;

  }

}