/*******************************************************************************
 * <copyright> Copyright 2014 by E-Government Innovation Center EGIZ, Graz, Austria </copyright>
 * PDF-AS has been contracted by the E-Government Innovation Center EGIZ, a
 * joint initiative of the Federal Chancellery Austria and Graz University of
 * Technology.
 * 
 * Licensed under the EUPL, Version 1.1 or - as soon they will be approved by
 * the European Commission - subsequent versions of the EUPL (the "Licence");
 * You may not use this work except in compliance with the Licence.
 * You may obtain a copy of the Licence at:
 * http://www.osor.eu/eupl/
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the Licence is distributed on an "AS IS" basis,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the Licence for the specific language governing permissions and
 * limitations under the Licence.
 * 
 * This product combines work with different licenses. See the "NOTICE" text
 * file for details on the various modules and licenses.
 * The "NOTICE" text file is part of the distribution. Any derivative works
 * that you distribute must include a readable copy of the "NOTICE" text file.
 ******************************************************************************/
package at.gv.egiz.pdfas.common.utils;

import java.awt.AlphaComposite;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.awt.image.ColorModel;
import java.awt.image.IndexColorModel;
import java.awt.image.WritableRaster;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.util.Iterator;

import javax.imageio.ImageIO;
import javax.imageio.ImageReader;
import javax.imageio.stream.ImageInputStream;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import at.gv.egiz.pdfas.common.exceptions.PdfAsException;
import at.gv.egiz.pdfas.common.settings.ISettings;

public class ImageUtils {
	
	private static final Logger logger = LoggerFactory
			.getLogger(ImageUtils.class);
	
	public static BufferedImage removeAlphaChannel(BufferedImage src) {
		if (src.getColorModel().hasAlpha())
        {
            // extract the alpha information
           // WritableRaster alphaRaster = src.
            //ColorModel cm = new ComponentColorModel(ColorSpace.getInstance(ColorSpace.CS_GRAY), 
            //        false, false, Transparency.OPAQUE, DataBuffer.TYPE_BYTE);
            //alpha = new BufferedImage(cm, alphaRaster, false, null);
            // create a RGB image without alpha
            
            BufferedImage image = new BufferedImage(src.getWidth(), src.getHeight(), BufferedImage.TYPE_INT_RGB);
            Graphics2D g = image.createGraphics();
            g.setComposite(AlphaComposite.Src);
            g.drawImage(src, 0, 0, null);
            g.dispose();
            return image;
        }
		return src;
	}
	
	public static BufferedImage convertRGBAToIndexed(BufferedImage src) {
		BufferedImage dest = new BufferedImage(src.getWidth(), src.getHeight(),
				BufferedImage.TYPE_BYTE_INDEXED);
		Graphics g = dest.getGraphics();
		g.setColor(new Color(231, 20, 189));
		g.fillRect(0, 0, dest.getWidth(), dest.getHeight()); // fill with a
																// hideous color
																// and make it
																// transparent
		dest = makeTransparent(dest, 0, 0);
		dest.createGraphics().drawImage(src, 0, 0, null);
		return dest;
	}

	public static BufferedImage makeTransparent(BufferedImage image, int x,
			int y) {
		ColorModel cm = image.getColorModel();
		if (!(cm instanceof IndexColorModel))
			return image; // sorry...
		IndexColorModel icm = (IndexColorModel) cm;
		WritableRaster raster = image.getRaster();
		int pixel = raster.getSample(x, y, 0); // pixel is offset in ICM's
												// palette
		int size = icm.getMapSize();
		byte[] reds = new byte[size];
		byte[] greens = new byte[size];
		byte[] blues = new byte[size];
		icm.getReds(reds);
		icm.getGreens(greens);
		icm.getBlues(blues);
		IndexColorModel icm2 = new IndexColorModel(8, size, reds, greens,
				blues, pixel);
		return new BufferedImage(icm2, raster, image.isAlphaPremultiplied(),
				null);
	}
	
	public static Dimension getImageDimensions(InputStream is) throws IOException {
		ImageInputStream in = ImageIO.createImageInputStream(is);
		try {
		    final Iterator<ImageReader> readers = ImageIO.getImageReaders(in);
		    if (readers.hasNext()) {
		        ImageReader reader = readers.next();
		        try {
		            reader.setInput(in);
		            return new Dimension(reader.getWidth(0), reader.getHeight(0));
		        } finally {
		            reader.dispose();
		        }
		    }
		    throw new IOException("Failed to read Image file");
		} finally {
		    if (in != null) in.close();
		}
	}
	
	public static File getImageFile(String imageFile, ISettings settings) throws PdfAsException, IOException {
		File img_file = new File(imageFile);
		if (!img_file.isAbsolute()) {
			logger.debug("Image file declaration is relative. Prepending path of resources directory.");
			logger.debug("Image Location: "
					+ settings.getWorkingDirectory()
					+ File.separator + imageFile);
			img_file = new File(settings.getWorkingDirectory()
					+ File.separator + imageFile);
		} else {
			logger.debug("Image file declaration is absolute. Skipping file relocation.");
		}

		if (!img_file.exists()) {
			logger.debug("Image file \""
					+ img_file.getCanonicalPath()
					+ "\" doesn't exist.");
			throw new PdfAsException("error.pdf.stamp.04");
		}
		
		return img_file;
	}
}