/*
    *  Licensed under the Apache License, Version 2.0 (the "License");
    *  you may not use this file except in compliance with the License.
    *  You may obtain a copy of the License at
    *
    *       http://www.apache.org/licenses/LICENSE-2.0
    *
    *  Unless required by applicable law or agreed to in writing, software
    *  distributed under the License is distributed on an "AS IS" BASIS,
   *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   *  See the License for the specific language governing permissions and
   *  limitations under the License.
   *  under the License.
   */
  
  package org.apache.commons.imaging.formats.pcx;
  
  import java.awt.image.BufferedImage;
  import java.io.IOException;
  import java.io.OutputStream;
  import java.util.Arrays;
  
  import org.apache.commons.imaging.PixelDensity;
  import org.apache.commons.imaging.common.AbstractBinaryOutputStream;
  import org.apache.commons.imaging.common.Allocator;
  import org.apache.commons.imaging.palette.PaletteFactory;
  import org.apache.commons.imaging.palette.SimplePalette;
  
  final class PcxWriter {
      private final int encoding;
      private final int bitDepthWanted;
      private final int planesWanted;
      private final PixelDensity pixelDensity;
      private final RleWriter rleWriter;
  
      PcxWriter(PcxImagingParameters params) {
          // uncompressed PCX files are not even documented in ZSoft's spec,
          // let alone supported by most image viewers
          if (params == null) {
              params = new PcxImagingParameters();
          }
          encoding = params.getCompression() == PcxConstants.PCX_COMPRESSION_UNCOMPRESSED ? PcxImageParser.PcxHeader.ENCODING_UNCOMPRESSED
                  : PcxImageParser.PcxHeader.ENCODING_RLE;
          rleWriter = new RleWriter(encoding != PcxImageParser.PcxHeader.ENCODING_UNCOMPRESSED);
          bitDepthWanted = params.getBitDepth();
          planesWanted = params.getPlanes();
          final PixelDensity pixelDensityParam = params.getPixelDensity();
          // DPI is mandatory, so we have to invent something
          pixelDensity = pixelDensityParam != null ? pixelDensityParam : PixelDensity.createFromPixelsPerInch(72, 72);
      }
  
      public void writeImage(final BufferedImage src, final OutputStream os) throws IOException {
          final PaletteFactory paletteFactory = new PaletteFactory();
          final SimplePalette palette = paletteFactory.makeExactRgbPaletteSimple(src, 256);
          @SuppressWarnings("resource") // Caller closes 'os'.
          final AbstractBinaryOutputStream bos = AbstractBinaryOutputStream.littleEndian(os);
          final int bitDepth;
          final int planes;
          if (palette == null || bitDepthWanted == 24 || bitDepthWanted == 32) {
              if (bitDepthWanted == 32) {
                  bitDepth = 32;
                  planes = 1;
              } else {
                  bitDepth = 8;
                  planes = 3;
              }
          } else if (palette.length() > 16 || bitDepthWanted == 8) {
              bitDepth = 8;
              planes = 1;
          } else if (palette.length() > 8 || bitDepthWanted == 4) {
              if (planesWanted == 1) {
                  bitDepth = 4;
                  planes = 1;
              } else {
                  bitDepth = 1;
                  planes = 4;
              }
          } else if (palette.length() > 4 || bitDepthWanted == 3) {
              bitDepth = 1;
              planes = 3;
          } else if (palette.length() > 2 || bitDepthWanted == 2) {
              if (planesWanted == 2) {
                  bitDepth = 1;
                  planes = 2;
              } else {
                  bitDepth = 2;
                  planes = 1;
              }
          } else {
              boolean onlyBlackAndWhite = true;
              if (palette.length() >= 1) {
                  final int rgb = palette.getEntry(0);
                  if (rgb != 0 && rgb != 0xffffff) {
                      onlyBlackAndWhite = false;
                  }
              }
              if (palette.length() == 2) {
                  final int rgb = palette.getEntry(1);
                  if (rgb != 0 && rgb != 0xffffff) {
                     onlyBlackAndWhite = false;
                 }
             }
             if (onlyBlackAndWhite) {
                 bitDepth = 1;
                 planes = 1;
             } else {
                 bitDepth = 1;
                 planes = 2;
             }
         }
 
         int bytesPerLine = (bitDepth * src.getWidth() + 7) / 8;
         if (bytesPerLine % 2 != 0) {
             // must be even:
             bytesPerLine++;
         }
 
         final byte[] palette16 = new byte[16 * 3];
         // TODO What's the right thing to do here for a null palette?
         final int paletteLen = palette != null ? palette.length() : 0;
         for (int i = 0; i < 16; i++) {
             final int rgb;
             if (i < paletteLen) {
                 rgb = palette.getEntry(i);
             } else {
                 rgb = 0;
             }
             palette16[3 * i + 0] = (byte) (0xff & rgb >> 16);
             palette16[3 * i + 1] = (byte) (0xff & rgb >> 8);
             palette16[3 * i + 2] = (byte) (0xff & rgb);
         }
 
         // PCX header
         bos.write(10); // manufacturer
         bos.write(bitDepth == 1 && planes == 1 ? 3 : 5); // version. Some apps only open black and white PCX with version=3.
         bos.write(encoding); // encoding
         bos.write(bitDepth); // bits per pixel
         bos.write2Bytes(0); // xMin
         bos.write2Bytes(0); // yMin
         bos.write2Bytes(src.getWidth() - 1); // xMax
         bos.write2Bytes(src.getHeight() - 1); // yMax
         bos.write2Bytes((short) Math.round(pixelDensity.horizontalDensityInches())); // hDpi
         bos.write2Bytes((short) Math.round(pixelDensity.verticalDensityInches())); // vDpi
         bos.write(palette16); // 16 color palette
         bos.write(0); // reserved
         bos.write(planes); // planes
         bos.write2Bytes(bytesPerLine); // bytes per line
         bos.write2Bytes(1); // palette info
         bos.write2Bytes(0); // hScreenSize
         bos.write2Bytes(0); // vScreenSize
         bos.write(new byte[54]);
 
         if (bitDepth == 32) {
             writePixels32(src, bytesPerLine, bos);
         } else {
             writePixels(src, bitDepth, planes, bytesPerLine, palette, bos);
         }
 
         if (bitDepth == 8 && planes == 1) {
             // 256 color palette
             bos.write(12);
             for (int i = 0; i < 256; i++) {
                 final int rgb;
                 if (i < palette.length()) {
                     rgb = palette.getEntry(i);
                 } else {
                     rgb = 0;
                 }
                 bos.write(rgb >> 16 & 0xff);
                 bos.write(rgb >> 8 & 0xff);
                 bos.write(rgb & 0xff);
             }
         }
     }
 
     private void writePixels(final BufferedImage src, final int bitDepth, final int planes, final int bytesPerLine, final SimplePalette palette,
             final AbstractBinaryOutputStream bos) throws IOException {
         final byte[] plane0 = Allocator.byteArray(bytesPerLine);
         final byte[] plane1 = Allocator.byteArray(bytesPerLine);
         final byte[] plane2 = Allocator.byteArray(bytesPerLine);
         final byte[] plane3 = Allocator.byteArray(bytesPerLine);
         final byte[][] allPlanes = { plane0, plane1, plane2, plane3 };
 
         for (int y = 0; y < src.getHeight(); y++) {
             for (int i = 0; i < planes; i++) {
                 Arrays.fill(allPlanes[i], (byte) 0);
             }
 
             if (bitDepth == 1 && planes == 1) {
                 for (int x = 0; x < src.getWidth(); x++) {
                     final int rgb = 0xffffff & src.getRGB(x, y);
                     final int bit;
                     if (rgb == 0x000000) {
                         bit = 0;
                     } else {
                         bit = 1;
                     }
                     plane0[x >>> 3] |= bit << 7 - (x & 7);
                 }
             } else if (bitDepth == 1 && planes == 2) {
                 for (int x = 0; x < src.getWidth(); x++) {
                     final int argb = src.getRGB(x, y);
                     final int index = palette.getPaletteIndex(0xffffff & argb);
                     plane0[x >>> 3] |= (index & 1) << 7 - (x & 7);
                     plane1[x >>> 3] |= (index & 2) >> 1 << 7 - (x & 7);
                 }
             } else if (bitDepth == 1 && planes == 3) {
                 for (int x = 0; x < src.getWidth(); x++) {
                     final int argb = src.getRGB(x, y);
                     final int index = palette.getPaletteIndex(0xffffff & argb);
                     plane0[x >>> 3] |= (index & 1) << 7 - (x & 7);
                     plane1[x >>> 3] |= (index & 2) >> 1 << 7 - (x & 7);
                     plane2[x >>> 3] |= (index & 4) >> 2 << 7 - (x & 7);
                 }
             } else if (bitDepth == 1 && planes == 4) {
                 for (int x = 0; x < src.getWidth(); x++) {
                     final int argb = src.getRGB(x, y);
                     final int index = palette.getPaletteIndex(0xffffff & argb);
                     plane0[x >>> 3] |= (index & 1) << 7 - (x & 7);
                     plane1[x >>> 3] |= (index & 2) >> 1 << 7 - (x & 7);
                     plane2[x >>> 3] |= (index & 4) >> 2 << 7 - (x & 7);
                     plane3[x >>> 3] |= (index & 8) >> 3 << 7 - (x & 7);
                 }
             } else if (bitDepth == 2 && planes == 1) {
                 for (int x = 0; x < src.getWidth(); x++) {
                     final int argb = src.getRGB(x, y);
                     final int index = palette.getPaletteIndex(0xffffff & argb);
                     plane0[x >>> 2] |= index << 2 * (3 - (x & 3));
                 }
             } else if (bitDepth == 4 && planes == 1) {
                 for (int x = 0; x < src.getWidth(); x++) {
                     final int argb = src.getRGB(x, y);
                     final int index = palette.getPaletteIndex(0xffffff & argb);
                     plane0[x >>> 1] |= index << 4 * (1 - (x & 1));
                 }
             } else if (bitDepth == 8 && planes == 1) {
                 for (int x = 0; x < src.getWidth(); x++) {
                     final int argb = src.getRGB(x, y);
                     final int index = palette.getPaletteIndex(0xffffff & argb);
                     plane0[x] = (byte) index;
                 }
             } else if (bitDepth == 8 && planes == 3) {
                 for (int x = 0; x < src.getWidth(); x++) {
                     final int argb = src.getRGB(x, y);
                     plane0[x] = (byte) (argb >>> 16);
                     plane1[x] = (byte) (argb >>> 8);
                     plane2[x] = (byte) argb;
                 }
             }
 
             for (int i = 0; i < planes; i++) {
                 rleWriter.write(bos, allPlanes[i]);
             }
         }
         rleWriter.flush(bos);
     }
 
     private void writePixels32(final BufferedImage src, final int bytesPerLine, final AbstractBinaryOutputStream bos) throws IOException {
 
         final int[] rgbs = Allocator.intArray(src.getWidth());
         final byte[] plane = Allocator.byteArray(4 * bytesPerLine);
         for (int y = 0; y < src.getHeight(); y++) {
             src.getRGB(0, y, src.getWidth(), 1, rgbs, 0, src.getWidth());
             for (int x = 0; x < rgbs.length; x++) {
                 plane[4 * x + 0] = (byte) rgbs[x];
                 plane[4 * x + 1] = (byte) (rgbs[x] >> 8);
                 plane[4 * x + 2] = (byte) (rgbs[x] >> 16);
                 plane[4 * x + 3] = 0;
             }
             rleWriter.write(bos, plane);
         }
         rleWriter.flush(bos);
     }
 }