import java.net.*;
import java.io.*;
import java.awt.image.*;
import java.util.Hashtable;
import java.util.Enumeration;

public class fitsContentHandler extends ContentHandler {

  public Object getContent(URLConnection uc) {
  
    int width = -1;
    int height = -1;
    int bitpix = 16;
    int[] theData = null;
    int naxis = 2;
    Hashtable header = null;
    
    try {  
      DataInputStream dis = new DataInputStream(uc.getInputStream());
      header = readHeader(dis);

      bitpix = getIntFromHeader("BITPIX  ", -1, header);
      if (bitpix  <= 0) return null;
      naxis = getIntFromHeader("NAXIS   ", -1, header);
      if (naxis  < 1) return null;
      width = getIntFromHeader("NAXIS1  ", -1, header);
      if (width  <= 0) return null;
      if (naxis == 1) height = 1;
      else height = getIntFromHeader("NAXIS2  ", -1, header);
      if (height  <= 0) return null;
      
      if (bitpix == 16) {
          short[] theInput =  new short[height * width];  
          for (int i = 0; i < theInput.length; i++) {
            theInput[i] = dis.readShort();
          }
          theData = scaleArray(theInput);
      }
      else if (bitpix == 32) {
        int[] theInput =  new int[height * width];  
        for (int i = 0; i < theInput.length; i++) {
          theInput[i] = dis.readInt();
        }
        theData = scaleArray(theInput);
     }
     else if (bitpix == 64) { 
       long[] theInput =  new long[height * width];  
       for (int i = 0; i < theInput.length; i++) {
         theInput[i] = dis.readLong();
       }
      theData = scaleArray(theInput);
     }
     else if (bitpix == -32) { 
       float[] theInput =  new float[height * width];  
       for (int i = 0; i < theInput.length; i++) {
         theInput[i] = dis.readFloat();
       }
       theData = scaleArray(theInput);
     }
     else if (bitpix == -64) { 
       double[] theInput =  new double[height * width];  
       for (int i = 0; i < theInput.length; i++) {
         theInput[i] = dis.readDouble();
        }
        theData = scaleArray(theInput);          
     } 
     else {
       System.err.println("Invalid BITPIX");
       return null;
     } // end if-else-if
      
    }  // end try
    catch (IOException e) {
    
    }
 
    return new  MemoryImageSource(width,  height,  theData,  0,  width);

}  // end getContent
  
  Hashtable readHeader(DataInputStream dis) throws IOException {
  
    int blocksize = 2880;
    int fieldsize = 80;
    String key, value;
    int linesRead = 0;
    
    byte[] buffer = new byte[fieldsize];
    
    Hashtable h = new Hashtable();
    while (true) {
      dis.readFully(buffer);
      key =  new String(buffer, 0, 0, 8);
      linesRead++;
      if (key.substring(0, 3).equals("END")) break;
      if (buffer[8] != '=' || buffer[9] != ' ') continue;
      value = new String(buffer, 0, 10, 20);
      h.put(key, value);
    }
    int linesLeftToRead = (blocksize - ((linesRead * fieldsize) % blocksize))/fieldsize;
    for (int i = 0; i < linesLeftToRead; i++) dis.readFully(buffer);
    
    return h;

  }
  
  int getIntFromHeader(String name, int Default, Hashtable header) {
  
      String s = "";
      int result = Default;
      
      try {
        s = (String) header.get(name);
      }
      catch (NullPointerException e) {     
        return Default;
      }
      try {
        result = Integer.parseInt(s.trim());
      }
      catch (NumberFormatException e) {  
        System.err.println(e);
        System.err.println(s);
        return Default;
      }
      
      return result;
  
  }
  
  int[] scaleArray(short[] theInput) {
  
    int theData[] = new int[theInput.length];
    int max = 0;
    int min = 0;
    for (int i = 0; i < theInput.length; i++) {
      if (theInput[i] > max) max = theInput[i];
      if (theInput[i] < min) min = theInput[i];
    }
    long r = max - min;
    double a = 255.0/r;
    double b = -a * min;
    int opaque = 255;
    for (int i = 0; i < theData.length; i++) {
      int temp = (int) (theInput[i] * a + b);
      theData[i] =  (opaque << 24)  | (temp << 16)  | (temp << 8) | temp;
    }
    return theData;

  }  
  
  int[] scaleArray(int[] theInput) {
  
    int theData[] = new int[theInput.length];
    int max = 0;
    int min = 0;
    for (int i = 0; i < theInput.length; i++) {
      if (theInput[i] > max) max = theInput[i];
      if (theInput[i] < min) min = theInput[i];
    }
    long r = max - min;
    double a = 255.0/r;
    double b = -a * min;
    int opaque = 255;
    for (int i = 0; i < theData.length; i++) {
      int temp = (int) (theInput[i] * a + b);
      theData[i] =  (opaque << 24)  | (temp << 16)  | (temp << 8) | temp;
    }
    return theData;

  }  
  
  int[] scaleArray(long[] theInput) {
  
    int theData[] = new int[theInput.length];
    long max = 0;
    long min = 0;
    for (int i = 0; i < theInput.length; i++) {
      if (theInput[i] > max) max = theInput[i];
      if (theInput[i] < min) min = theInput[i];
    }
    long r = max - min;
    double a = 255.0/r;
    double b = -a * min;
    int opaque = 255;
    for (int i = 0; i < theData.length; i++) {
      int temp = (int) (theInput[i] * a + b);
      theData[i] =  (opaque << 24)  | (temp << 16)  | (temp << 8) | temp;
    }
    return theData;

  }  
  
  int[] scaleArray(double[] theInput) {
  
    int theData[] = new int[theInput.length];
    double max = 0;
    double min = 0;
    for (int i = 0; i < theInput.length; i++) {
      if (theInput[i] > max) max = theInput[i];
      if (theInput[i] < min) min = theInput[i];
    }
    double r = max - min;
    double a = 255.0/r;
    double b = -a * min;
    int opaque = 255;
    for (int i = 0; i < theData.length; i++) {
      int temp = (int) (theInput[i] * a + b);
      theData[i] =  (opaque << 24)  | (temp << 16)  | (temp << 8) | temp;
    }
    return theData;

  }
  
  int[] scaleArray(float[] theInput) {
  
    int theData[] = new int[theInput.length];
    float max = 0;
    float min = 0;
    for (int i = 0; i < theInput.length; i++) {
      if (theInput[i] > max) max = theInput[i];
      if (theInput[i] < min) min = theInput[i];
    }
    double r = max - min;
    double a = 255.0/r;
    double b = -a * min;
    int opaque = 255;
    for (int i = 0; i < theData.length; i++) {
      int temp = (int) (theInput[i] * a + b);
      theData[i] =  (opaque << 24)  | (temp << 16)  | (temp << 8) | temp;
    }
    return theData;

  }

}