/*
 * Copyright (c) 2003-2005 Sun Microsystems, Inc. All Rights Reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 * 
 * - Redistribution of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * 
 * - Redistribution in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * 
 * Neither the name of Sun Microsystems, Inc. or the names of
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 * 
 * This software is provided "AS IS," without a warranty of any kind. ALL
 * EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES,
 * INCLUDING ANY IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A
 * PARTICULAR PURPOSE OR NON-INFRINGEMENT, ARE HEREBY EXCLUDED. SUN
 * MICROSYSTEMS, INC. ("SUN") AND ITS LICENSORS SHALL NOT BE LIABLE FOR
 * ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING OR
 * DISTRIBUTING THIS SOFTWARE OR ITS DERIVATIVES. IN NO EVENT WILL SUN OR
 * ITS LICENSORS BE LIABLE FOR ANY LOST REVENUE, PROFIT OR DATA, OR FOR
 * DIRECT, INDIRECT, SPECIAL, CONSEQUENTIAL, INCIDENTAL OR PUNITIVE
 * DAMAGES, HOWEVER CAUSED AND REGARDLESS OF THE THEORY OF LIABILITY,
 * ARISING OUT OF THE USE OF OR INABILITY TO USE THIS SOFTWARE, EVEN IF
 * SUN HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
 * 
 * You acknowledge that this software is not designed or intended for use
 * in the design, construction, operation or maintenance of any nuclear
 * facility.
 * 
 * Sun gratefully acknowledges that this software was originally authored
 * and developed by Kenneth Bradley Russell and Christopher John Kline.
 */

package com.sun.opengl.util.texture.spi;

import java.io.*;
import java.nio.*;
import java.nio.channels.*;
import javax.media.opengl.*;
import com.sun.opengl.util.*;

/**
 * Targa image reader and writer adapted from sources of the <a href =
 * "http://java.sun.com/products/jimi/">Jimi</a> image I/O class library.
 *
 * <P>
 *
 * Image decoder for image data stored in TGA file format.
 * Currently only the original TGA file format is supported. This is
 * because the new TGA format has data at the end of the file, getting
 * to the end of a file in an InputStream orient environment presents
 * several difficulties which are avoided at the moment.
 *
 * <P>
 *
 * This is a simple decoder and is only setup to load a single image
 * from the input stream
 *
 * <P>
 *
 * @author    Robin Luiten
 * @author    Kenneth Russell
 * @version    $Revision$
 */

public class TGAImage {
  private Header header;
  private int    format;
  private ByteBuffer data;

  private TGAImage(Header header) {
    this.header = header;
  }

  /**
   * This class reads in all of the TGA image header in addition it also
   * reads in the imageID field as it is convenient to handle that here.
   *
   * @author    Robin Luiten
   * @version   1.1
   */
  public static class Header {
    /** Set of possible file format TGA types */
    public final static int TYPE_NEW = 0;
    public final static int TYPE_OLD = 1;
    public final static int TYPE_UNK = 2;               // cant rewind stream so unknown for now.

    /**  Set of possible image types in TGA file */
    public final static int NO_IMAGE = 0;               // no image data
    public final static int UCOLORMAPPED = 1;           // uncompressed color mapped image
    public final static int UTRUECOLOR = 2;             // uncompressed true color image
    public final static int UBLACKWHITE = 3;            // uncompressed black and white image
    public final static int COLORMAPPED = 9;            // compressed color mapped image
    public final static int TRUECOLOR = 10;             // compressed true color image
    public final static int BLACKWHITE = 11;            // compressed black and white image

    /** Field image descriptor bitfield values definitions */
    public final static int ID_ATTRIBPERPIXEL = 0xF;
    public final static int ID_RIGHTTOLEFT = 0x10;
    public final static int ID_TOPTOBOTTOM = 0x20;
    public final static int ID_INTERLEAVE  = 0xC0;

    /** Field image descriptor / interleave values */
    public final static int I_NOTINTERLEAVED = 0;
    public final static int I_TWOWAY = 1;
    public final static int I_FOURWAY = 2;

    /** Type of this TGA file format */
    private int tgaType;

    /** initial TGA image data fields */
    private int idLength;         // byte value
    private int colorMapType;     // byte value
    private int imageType;        // byte value

    /** TGA image colour map fields */
    private int firstEntryIndex;
    private int colorMapLength;
    private byte colorMapEntrySize;

    /** TGA image specification fields */
    private int xOrigin;
    private int yOrigin;
    private int width;
    private int height;
    private byte pixelDepth;
    private byte imageDescriptor;

    private byte[] imageIDbuf;
    private String imageID;

    // For construction from user data
    Header() {
      tgaType = TYPE_OLD; // dont try and get footer.
    }

    Header(LEDataInputStream in) throws IOException {
      int ret;

      tgaType = TYPE_OLD; // dont try and get footer.

      // initial header fields
      idLength = in.readUnsignedByte();    
      colorMapType = in.readUnsignedByte();
      imageType = in.readUnsignedByte();    

      // color map header fields
      firstEntryIndex = in.readUnsignedShort();
      colorMapLength = in.readUnsignedShort();
      colorMapEntrySize = in.readByte();

      // TGA image specification fields
      xOrigin = in.readUnsignedShort();
      yOrigin = in.readUnsignedShort();
      width = in.readUnsignedShort();
      height = in.readUnsignedShort();
      pixelDepth = in.readByte();
      imageDescriptor = in.readByte();

      if (idLength > 0) {
        imageIDbuf = new byte[idLength];
        in.read(imageIDbuf, 0, idLength);
        imageID = new String(imageIDbuf, "US-ASCII");
      }
    }

    public int tgaType()                 { return tgaType; }

    /** initial TGA image data fields */
    public int idLength()                { return idLength; }
    public int colorMapType()            { return colorMapType; }
    public int imageType()               { return imageType; }

    /** TGA image colour map fields */
    public int firstEntryIndex()         { return firstEntryIndex; }
    public int colorMapLength()          { return colorMapLength; }
    public byte colorMapEntrySize()      { return colorMapEntrySize; }

    /** TGA image specification fields */
    public int xOrigin()                 { return xOrigin; }
    public int yOrigin()                 { return yOrigin; }
    public int width()                   { return width; }
    public int height()                  { return height; }
    public byte pixelDepth()             { return pixelDepth; }
    public byte imageDescriptor()        { return imageDescriptor; }

    /** bitfields in imageDescriptor */
    public byte attribPerPixel()         { return (byte)(imageDescriptor & ID_ATTRIBPERPIXEL); }
    public boolean rightToLeft()         { return ((imageDescriptor & ID_RIGHTTOLEFT) != 0); }
    public boolean topToBottom()         { return ((imageDescriptor & ID_TOPTOBOTTOM) != 0); }
    public byte interleave()             { return (byte)((imageDescriptor & ID_INTERLEAVE) >> 6); }

    public byte[] imageIDbuf()           { return imageIDbuf; }
    public String imageID()              { return imageID; }

    public String toString() {
      return "TGA Header " +
        " id length: " + idLength +
        " color map type: "+ colorMapType +
        " image type: "+ imageType +
        " first entry index: " + firstEntryIndex +
        " color map length: " + colorMapLength +
        " color map entry size: " + colorMapEntrySize +
        " x Origin: " + xOrigin +
        " y Origin: " + yOrigin +
        " width: "+ width +
        " height: "+ height +
        " pixel depth: "+ pixelDepth +
        " image descriptor: "+ imageDescriptor +
        (imageIDbuf == null ? "" : (" ID String: " + imageID));
    }

    public int size() { return 18 + idLength; }

    // buf must be in little-endian byte order
    private void write(ByteBuffer buf) {
      buf.put((byte) idLength);
      buf.put((byte) colorMapType);
      buf.put((byte) imageType);
      buf.putShort((short) firstEntryIndex);
      buf.putShort((short) colorMapLength);
      buf.put((byte) colorMapEntrySize);
      buf.putShort((short) xOrigin);
      buf.putShort((short) yOrigin);
      buf.putShort((short) width);
      buf.putShort((short) height);
      buf.put((byte) pixelDepth);
      buf.put((byte) imageDescriptor);
      if (idLength > 0) {
        try {
          byte[] chars = imageID.getBytes("US-ASCII");
          buf.put(chars);
        } catch (UnsupportedEncodingException e) {
          throw new RuntimeException(e);
        }
      }
    }
  }


  /**
   * Identifies the image type of the tga image data and loads
   * it into the JimiImage structure. This was taken from the
   * prototype and modified for the new Jimi structure
   */
  private void decodeImage(LEDataInputStream dIn) throws IOException {
    switch (header.imageType()) {
    case Header.UCOLORMAPPED:
      throw new IOException("TGADecoder Uncompressed Colormapped images not supported");

    case Header.UTRUECOLOR:    // pixelDepth 15, 16, 24 and 32
      switch (header.pixelDepth) {
      case 16:
        throw new IOException("TGADecoder Compressed 16-bit True Color images not supported");

      case 24:
      case 32:
        decodeRGBImageU24_32(dIn);
        break;
      }
      break;

    case Header.UBLACKWHITE:
      throw new IOException("TGADecoder Uncompressed Grayscale images not supported");

    case Header.COLORMAPPED:
      throw new IOException("TGADecoder Compressed Colormapped images not supported");

    case Header.TRUECOLOR:
      throw new IOException("TGADecoder Compressed True Color images not supported");

    case Header.BLACKWHITE:
      throw new IOException("TGADecoder Compressed Grayscale images not supported");
    }
  }
  
  /**
   * This assumes that the body is for a 24 bit or 32 bit for a
   * RGB or ARGB image respectively.
   */
  private void decodeRGBImageU24_32(LEDataInputStream dIn) throws IOException {
    int i;    // row index
    int j;    // column index
    int y;    // output row index
    int raw;  // index through the raw input buffer
    int rawWidth = header.width() * (header.pixelDepth() / 8);
    byte[] rawBuf = new byte[rawWidth];
    byte[] tmpData = new byte[rawWidth * header.height()];

    if (header.pixelDepth() == 24) {
      format = GL.GL_BGR;
    } else {
      assert header.pixelDepth() == 32;
      format = GL.GL_BGRA;
    }

    for (i = 0; i < header.height(); ++i) {
      dIn.readFully(rawBuf, 0, rawWidth);

      if (header.topToBottom())
        y = header.height - i - 1; // range 0 to (header.height - 1)
      else
        y = i;

      System.arraycopy(rawBuf, 0, tmpData, y * rawWidth, rawBuf.length);
    }

    data = ByteBuffer.wrap(tmpData);
  }

  /** Returns the width of the image. */
  public int getWidth()    { return header.width(); }

  /** Returns the height of the image. */
  public int getHeight()   { return header.height(); }

  /** Returns the OpenGL format for this texture; e.g. GL.GL_BGR or GL.GL_BGRA. */
  public int getGLFormat() { return format; }

  /** Returns the raw data for this texture in the correct
      (bottom-to-top) order for calls to glTexImage2D. */
  public ByteBuffer getData()  { return data; }

  /** Reads a Targa image from the specified file. */
  public static TGAImage read(String filename) throws IOException {
    return read(new FileInputStream(filename));
  }

  /** Reads a Targa image from the specified InputStream. */
  public static TGAImage read(InputStream in) throws IOException {
    LEDataInputStream dIn = new LEDataInputStream(new BufferedInputStream(in));

    Header header = new Header(dIn);
    TGAImage res = new TGAImage(header);
    res.decodeImage(dIn);
    return res;
  }

  /** Writes the image in Targa format to the specified file name. */
  public void write(String filename) throws IOException {
    write(new File(filename));
  }

  /** Writes the image in Targa format to the specified file. */
  public void write(File file) throws IOException {
    FileOutputStream stream = new FileOutputStream(file);
    FileChannel chan = stream.getChannel();
    ByteBuffer buf = ByteBuffer.allocate(header.size());
    buf.order(ByteOrder.LITTLE_ENDIAN);
    header.write(buf);
    buf.rewind();
    chan.write(buf);
    chan.write(data);
    data.rewind();
    chan.force(true);
    chan.close();
    stream.close();
  }

  /** Creates a TGAImage from data supplied by the end user. Shares
      data with the passed ByteBuffer. Assumes the data is already in
      the correct byte order for writing to disk, i.e., BGR or
      BGRA. */
  public static TGAImage createFromData(int width,
                                        int height,
                                        boolean hasAlpha,
                                        boolean topToBottom,
                                        ByteBuffer data) {
    Header header = new Header();
    header.imageType = Header.UTRUECOLOR;
    header.width = width;
    header.height = height;
    header.pixelDepth = (byte) (hasAlpha ? 32 : 24);
    header.imageDescriptor = (byte) (topToBottom ? Header.ID_TOPTOBOTTOM : 0);
    // Note ID not supported
    TGAImage ret = new TGAImage(header);
    ret.data = data;
    return ret;
  }
}