/*
    * Licensed to the Apache Software Foundation (ASF) under one or more
    * contributor license agreements.  See the NOTICE file distributed with
    * this work for additional information regarding copyright ownership.
    * The ASF licenses this file to You 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.
   */
  package org.apache.commons.imaging.formats.png;
  
  import java.awt.image.BufferedImage;
  import java.io.IOException;
  import java.io.InputStream;
  
  import org.apache.commons.imaging.ImagingException;
  import org.apache.commons.imaging.formats.png.chunks.PngChunkPlte;
  import org.apache.commons.imaging.formats.png.transparencyfilters.AbstractTransparencyFilter;
  
  final class ScanExpediterInterlaced extends AbstractScanExpediter {
      private static final int[] STARTING_ROW = { 0, 0, 4, 0, 2, 0, 1 };
      private static final int[] STARTING_COL = { 0, 4, 0, 2, 0, 1, 0 };
      private static final int[] ROW_INCREMENT = { 8, 8, 8, 4, 4, 2, 2 };
      private static final int[] COL_INCREMENT = { 8, 8, 4, 4, 2, 2, 1 };
  //    private static final int[] Block_Height = { 8, 8, 4, 4, 2, 2, 1 };
  //    private static final int[] Block_Width = { 8, 4, 4, 2, 2, 1, 1 };
  
      ScanExpediterInterlaced(final int width, final int height, final InputStream is, final BufferedImage bi, final PngColorType pngColorType,
              final int bitDepth, final int bitsPerPixel, final PngChunkPlte pngChunkPLTE, final GammaCorrection gammaCorrection,
              final AbstractTransparencyFilter abstractTransparencyFilter) {
          super(width, height, is, bi, pngColorType, bitDepth, bitsPerPixel, pngChunkPLTE, gammaCorrection, abstractTransparencyFilter);
      }
  
      @Override
      public void drive() throws ImagingException, IOException {
  
          int pass = 1;
          while (pass <= 7) {
              byte[] prev = null;
  
              int y = STARTING_ROW[pass - 1];
              // int y_stride = ROW_INCREMENT[pass - 1];
              // final boolean rows_in_pass = (y < height);
              while (y < height) {
                  int x = STARTING_COL[pass - 1];
                  int pixelIndexInScanline = 0;
  
                  if (x < width) {
                      // only get data if there are pixels in this scanline/pass
                      final int columnsInRow = 1 + (width - STARTING_COL[pass - 1] - 1) / COL_INCREMENT[pass - 1];
                      final int bitsPerScanLine = bitsPerPixel * columnsInRow;
                      final int pixelBytesPerScanLine = getBitsToBytesRoundingUp(bitsPerScanLine);
  
                      final byte[] unfiltered = getNextScanline(is, pixelBytesPerScanLine, prev, bytesPerPixel);
  
                      prev = unfiltered;
  
                      final BitParser fBitParser = new BitParser(unfiltered, bitsPerPixel, bitDepth);
  
                      while (x < width) {
                          visit(x, y, bi, fBitParser, pixelIndexInScanline);
  
                          x += COL_INCREMENT[pass - 1];
                          pixelIndexInScanline++;
                      }
                  }
                  y += ROW_INCREMENT[pass - 1];
              }
              pass += 1;
          }
      }
  
      private void visit(final int x, final int y, final BufferedImage bi, final BitParser fBitParser, final int pixelIndexInScanline)
              throws ImagingException, IOException {
          final int rgb = getRgb(fBitParser, pixelIndexInScanline);
          bi.setRGB(x, y, rgb);
      }
  }