/*
    * 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 static org.junit.jupiter.api.Assertions.assertArrayEquals;
  
  import java.awt.image.BufferedImage;
  import java.io.ByteArrayInputStream;
  import java.io.ByteArrayOutputStream;
  import java.io.IOException;
  
  import javax.imageio.ImageIO;
  
  import org.junit.jupiter.api.BeforeAll;
  import org.junit.jupiter.api.BeforeEach;
  import org.junit.jupiter.api.Test;
  
  /**
   * Provides a test for the PngWriter using predictors
   */
  public class PngWritePredictorTest {
  
      @BeforeAll
      public static void setUpClass() {
      }
  
      public PngWritePredictorTest() {
      }
  
      /**
       * Populate an integer pixel array for a 256-by-256 image with varied colors across the image area and a white and black line down the main diagonal.
       *
       * @return a valid array of integers.
       */
      private int[] populateARGB() {
          // populate array with a blend of color components
          final int[] argb = new int[256 * 256];
          for (int i = 0; i < 256; i++) {
              for (int j = 0; j < 256; j++) {
                  final int red = i;
                  final int green = 255 - i;
                  final int blue = j;
                  argb[i * 256 + j] = ((0xff00 | red) << 8 | green) << 8 | blue;
              }
          }
  
          // also draw a black and white strip down main diagonal
          for (int i = 0; i < 256; i++) {
              argb[i * 256 + i] = 0xff000000;
              if (i < 255) {
                  argb[i * 256 + i + 1] = 0xffffffff;
              }
          }
          return argb;
      }
  
      @BeforeEach
      public void setUp() {
      }
  
      @Test
      void testWriteWithPredictor() throws IOException {
          final int[] argb = populateARGB();
  
          // Test the RGB (no alpha) case
          BufferedImage bImage = new BufferedImage(256, 256, BufferedImage.TYPE_INT_RGB);
          bImage.setRGB(0, 0, 256, 256, argb, 0, 256);
  
          byte[] tempFile = null;
  
          final PngImagingParameters params = new PngImagingParameters();
          params.setPredictorEnabled(true);
          final PngImageParser parser = new PngImageParser();
          try (ByteArrayOutputStream bos = new ByteArrayOutputStream()) {
              parser.writeImage(bImage, bos, params);
              tempFile = bos.toByteArray();
          }
  
          int[] brgb = new int[256 * 256];
          bImage = ImageIO.read(new ByteArrayInputStream(tempFile));
          bImage.getRGB(0, 0, 256, 256, brgb, 0, 256);
          assertArrayEquals(argb, brgb, "Round trip for RGB failed");
  
          // Test the ARGB (some semi-transparent alpha) case
         for (int i = 0; i < 256; i++) {
             argb[i * 256 + i] &= 0x88ffffff;
         }
         bImage = new BufferedImage(256, 256, BufferedImage.TYPE_INT_ARGB);
         bImage.setRGB(0, 0, 256, 256, argb, 0, 256);
         try (ByteArrayOutputStream bos = new ByteArrayOutputStream()) {
             parser.writeImage(bImage, bos, params);
             tempFile = bos.toByteArray();
         }
         brgb = new int[256 * 256];
         bImage = ImageIO.read(new ByteArrayInputStream(tempFile));
         bImage.getRGB(0, 0, 256, 256, brgb, 0, 256);
         assertArrayEquals(argb, brgb, "Round trip for ARGB failed");
 
     }
 }