package com.atlassian.selenium.visualcomparison.utils;
   
   import org.apache.commons.lang.StringEscapeUtils;
   import org.apache.velocity.VelocityContext;
   
   import javax.imageio.ImageIO;
   import java.awt.*;
   import java.util.Collection;
   import java.util.Iterator;
  import java.util.List;
  import java.awt.image.BufferedImage;
  import java.io.File;
  import java.io.FileOutputStream;
  import java.io.IOException;
  import java.io.OutputStreamWriter;
  import java.util.ArrayList;
  
  public class ScreenshotDiff
  {
      private Screenshot oldScreenshot;
      private Screenshot newScreenshot;
      private String id;
      private ScreenResolution resolution;
      private BufferedImage diffImage;
      private List<BoundingBox> ignoreAreas;
      private Collection<PageDifference> differences;
  
      public ScreenshotDiff(Screenshot oldScreenshot, Screenshot newScreenshot,
              String id, ScreenResolution resolution,
              BufferedImage diffImage, ArrayList<BoundingBox> boxes, List<BoundingBox> ignoreAreas)
      {
          this.oldScreenshot = oldScreenshot;
          this.newScreenshot = newScreenshot;
          this.id = id;
          this.resolution = resolution;
          this.diffImage = diffImage;
          this.ignoreAreas = ignoreAreas;
          this.differences = new ArrayList<PageDifference>();
          for(BoundingBox box : boxes)
          {
              differences.add(new PageDifference(box));
          }
      }
      
      public Collection<PageDifference> getDifferences()
      {
          return differences;
      }
  
      /**
       * For tests.
       * @return a list of {@link BoundingBox} elements.
       */
      List<BoundingBox> getDiffAreas()
      {
          List<BoundingBox> boxes = new ArrayList<BoundingBox>();
          for (PageDifference difference : getDifferences())
          {
              boxes.add(difference.getBoundingBox());
          }
          return boxes;
      }
  
      public boolean hasDifferences()
      {
          return getDifferences().size() > 0;
      }
  
      public static String getImageOutputDir(String outputDir, String imageSubDir)
      {
          String imageOutputDir = outputDir + "/";
          if (imageSubDir != null && !imageSubDir.equals(""))
          {
              imageOutputDir = imageOutputDir + imageSubDir + "/";
          }
          return imageOutputDir;
      }
  
      public static String relativePath(final File file, final String relativeRoot)
      {
          final String fullPath = file.getAbsolutePath();
          String relativePath = fullPath.substring(fullPath.indexOf(relativeRoot)+relativeRoot.length());
          if (relativePath.startsWith("/")) relativePath = "." + relativePath;
          return relativePath;
      }
  
      public void writeDiffReport(String outputDir, String imageSubDir) throws Exception
      {
          if (!hasDifferences())
          {
              return;
          }
  
          String imageOutputDir = getImageOutputDir(outputDir, imageSubDir);
  
          int i = 0;
          for (PageDifference difference : getDifferences())
          {
              final BoundingBox box = difference.getBoundingBox();
             Graphics2D graphics = diffImage.createGraphics();
 
             String oldImagePath = imageOutputDir + "boxold" + i + "-" + id + "." + resolution + ".png";
             String newImagePath = imageOutputDir + "boxnew" + i + "-" + id + "." + resolution + ".png";
             String diffImagePath = imageOutputDir + "boxdiff" + i + "-" + id + "." + resolution + ".png";
 
             File oldImageFile = writeSubImage(oldScreenshot.getImage(), box, oldImagePath);
             File newImageFile = writeSubImage(newScreenshot.getImage(), box, newImagePath);
             File diffImageFile = writeSubImage(diffImage, box, diffImagePath);
             i++;
 
             // Once we've written the sub-images, draw a black box around each of the bounding boxes on the diff.
             graphics.setColor(Color.BLACK);
             BasicStroke stroke = new BasicStroke(2.0f,
                     BasicStroke.CAP_SQUARE,
                     BasicStroke.JOIN_MITER,
                     10.0f, new float[] { 10.0f }, 0.0f);
             graphics.setStroke(stroke);
             graphics.drawRect(box.getMarginLeft(), box.getMarginTop(), box.getMarginWidth(diffImage.getWidth() - 1), box.getMarginHeight(diffImage.getHeight() - 1));
 
             difference.setImages(
                 new PageDifferenceImages(oldImageFile,
                     newImageFile,
                     diffImageFile,
                     outputDir)
             );
         }
         if (ignoreAreas != null)
         {
             for (BoundingBox ignoreArea : ignoreAreas)
             {
                 Graphics2D graphics = diffImage.createGraphics();
                 // Draw an orange box around each of the ignored areas on the diff.
                 graphics.setColor(Color.ORANGE);
                 BasicStroke stroke = new BasicStroke(2.0f,
                         BasicStroke.CAP_SQUARE,
                         BasicStroke.JOIN_MITER,
                         10.0f, new float[] { 10.0f }, 0.0f);
                 graphics.setStroke(stroke);
                 graphics.drawRect(ignoreArea.getLeft(), ignoreArea.getTop(), ignoreArea.getWidth(), ignoreArea.getHeight());
             }
         }
 
         // Write the full diff image to the output directory.
         File diffImageFile = new File(imageOutputDir + "diff-" + id + "." + resolution + ".png");
         ImageIO.write(diffImage, "png", diffImageFile);
         diffImage.flush();
 
         // Copy the full baseline image to the output directory.
         File oldImageFile = new File(imageOutputDir + "old-" + oldScreenshot.getFileName());
         ImageIO.write(oldScreenshot.getImage(), "png", oldImageFile);
 
         // Copy the new image to the output directory.
         final File newImageFile = new File(imageOutputDir + newScreenshot.getFileName());
         ImageIO.write(newScreenshot.getImage(), "png", newImageFile);
 
         VelocityContext context = ReportRenderer.createContext();
         context.put("id", id);
         context.put("resolution", resolution);
         context.put("differences", differences);
         context.put("oldImageFile", relativePath(oldImageFile, outputDir));
         context.put("newImageFile", relativePath(newImageFile, outputDir));
         context.put("diffImageFile", relativePath(diffImageFile, outputDir));
         String report = ReportRenderer.render(context, "visual-regression-report-single.vm");
 
         OutputStreamWriter writer = new OutputStreamWriter(new FileOutputStream(new File(outputDir + "/report-" + id + "-" + resolution + ".html")));
         writer.append(report);
         writer.close();
     }
 
     private File writeSubImage(BufferedImage image, BoundingBox box, String outputPath) throws IOException
     {
         BufferedImage boxImage = image.getSubimage(box.getMarginLeft(), box.getMarginTop(), box.getMarginWidth(image.getWidth() - 1), box.getMarginHeight(image.getHeight() - 1));
         File outputFile = new File(outputPath);
         ImageIO.write(boxImage, "png", outputFile);
         return outputFile;
     }
 
 }