package org.exoplatform.services.document.impl.image;

import java.awt.Color;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.RenderingHints;
import java.awt.image.BufferedImage;

import org.exoplatform.services.document.image.ImageProcessingService;

public class ImageProcessingServiceImpl implements ImageProcessingService {

  public BufferedImage createCroppedImage(BufferedImage img, int chosenWidth, int chosenHeight) {
    int topX = 0; // X coordinate of the top left corner
    int topY = 0; // Y coordinate of the top left corner
    int newWidth = 0; // width of the scaled image before cropping
    int newHeight = 0; // height of the scaled image before cropping
    double factor = 0;
    double scaleHorizontalFactor = getScaleFactor(chosenWidth, img.getWidth());
    double scaleVerticalFactor = getScaleFactor(chosenHeight, img.getHeight());
    if (scaleVerticalFactor > scaleHorizontalFactor) {
      factor = scaleVerticalFactor;
      newWidth = (int) Math.round(img.getWidth() * factor);
      newHeight = (int) Math.round(img.getHeight() * factor);
      topX = (int) Math.round((newWidth - chosenWidth) / 2);
    } else {
      factor = scaleHorizontalFactor;
      newWidth = (int) Math.round(img.getWidth() * factor);
      newHeight = (int) Math.round(img.getHeight() * factor);
      topY = (int) Math.round((newHeight - chosenHeight) / 2);
    }

    // Scale the image: BufferedImage needed for "subImaging"
    BufferedImage scaledImage = new BufferedImage(newWidth, newHeight, BufferedImage.TYPE_INT_RGB);
    Graphics2D aImage = scaledImage.createGraphics();
    aImage.setRenderingHint(RenderingHints.KEY_INTERPOLATION,
                            RenderingHints.VALUE_INTERPOLATION_BICUBIC);
    aImage.drawImage(img, 0, 0, newWidth, newHeight, null);

    // Crop the image
    BufferedImage croppedImage = scaledImage.getSubimage(topX, topY, chosenWidth, chosenHeight);

    // Create the new image
    BufferedImage imageBuf = new BufferedImage(chosenWidth,
                                               chosenHeight,
                                               BufferedImage.TYPE_INT_RGB);
    Graphics2D newImage = imageBuf.createGraphics();
    newImage.setRenderingHint(RenderingHints.KEY_INTERPOLATION,
                              RenderingHints.VALUE_INTERPOLATION_BICUBIC);
    newImage.drawImage(croppedImage, 0, 0, chosenWidth, chosenHeight, null);

    return imageBuf;
  }

  public BufferedImage createBoundImage(BufferedImage img,
                                        int chosenWidth,
                                        int chosenHeight,
                                        String bgColor) {
    // Calculate the scale factor according to bounds
    double factor = 0;
    double scaleHorizontalFactor = getScaleFactor(chosenWidth, img.getWidth());
    double scaleVerticalFactor = getScaleFactor(chosenHeight, img.getHeight());
    if (scaleVerticalFactor > scaleHorizontalFactor) {
      factor = scaleHorizontalFactor;
    } else {
      factor = scaleVerticalFactor;
    }

    int newWidth = (int) Math.round(img.getWidth() * factor);
    int newHeight = (int) Math.round(img.getHeight() * factor);

    // Scale the image
    Image imgScaled = img.getScaledInstance(newWidth, newHeight, Image.SCALE_DEFAULT);

    // Copy the scaled image into the new one
    BufferedImage imageBuf = new BufferedImage(chosenWidth,
                                               chosenHeight,
                                               BufferedImage.TYPE_INT_RGB);
    Graphics2D newImage = imageBuf.createGraphics();
    newImage.setRenderingHint(RenderingHints.KEY_INTERPOLATION,
                              RenderingHints.VALUE_INTERPOLATION_BICUBIC);
    newImage.setBackground(hexToColor(bgColor)); // Set the background color
    newImage.clearRect(0, 0, chosenWidth, chosenHeight);
    newImage.drawImage(imgScaled,
                       getImageOffset(chosenWidth, newWidth),
                       getImageOffset(chosenHeight, newHeight),
                       newWidth,
                       newHeight,
                       null);

    return imageBuf;
  }

  public BufferedImage createScaledImage(BufferedImage img, double factor) {
    // The original size
    int imgWidth = img.getWidth();
    int imgHeight = img.getHeight();
    // The scaled size
    int newWidth = (new Double(imgWidth * factor)).intValue();
    int newHeight = (new Double(imgHeight * factor)).intValue();

    // Scale the image
    Image imgScaled = img.getScaledInstance(newWidth, newHeight, Image.SCALE_DEFAULT);
    BufferedImage scaledImage = new BufferedImage(newWidth, newHeight, BufferedImage.TYPE_INT_RGB);
    Graphics2D aImage = scaledImage.createGraphics();
    aImage.setRenderingHint(RenderingHints.KEY_INTERPOLATION,
                            RenderingHints.VALUE_INTERPOLATION_BICUBIC);
    aImage.drawImage(imgScaled, 0, 0, newWidth, newHeight, null);

    return scaledImage;
  }

  private double getScaleFactor(int chosenDim, int imgDim) {
    return (double) chosenDim / (double) imgDim;
  }

  private int getImageOffset(int newDim, int oldDim) {
    int offset = 0;
    if (newDim >= oldDim) {
      offset = Math.round((newDim - oldDim) / 2);
    }
    return offset;
  }

  private Color hexToColor(final String rrggbb) {
    Color color = Color.WHITE; // Default value: white

    String hexColor = "";
    if (rrggbb.startsWith("#")) {
      hexColor = rrggbb.substring(1);
    } else {
      hexColor = rrggbb;
    }

    int length = hexColor.length();
    if (length == 3 || length == 6) {
      try {
        if (length == 3) { // Short syntax
          char c1, c2, c3;
          c1 = hexColor.charAt(0);
          c2 = hexColor.charAt(1);
          c3 = hexColor.charAt(2);
          color = Color.decode("0x" + c1 + c1 + c2 + c2 + c3 + c3);
        } else {
          color = Color.decode("0x" + hexColor);
        }
      } catch (NumberFormatException nfe) {
      }
    }

    return color;
  }

}