/*
 * 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.pdfbox.pdmodel.graphics.color;

import java.util.Arrays;

import org.apache.pdfbox.cos.COSName;

import java.awt.color.ColorSpace;
import java.awt.color.ICC_ColorSpace;
import java.awt.color.ICC_Profile;
import java.awt.image.BufferedImage;
import java.awt.image.WritableRaster;
import java.io.BufferedInputStream;
import java.io.IOException;

import java.io.InputStream;

/**
 * Allows colors to be specified according to the subtractive CMYK (cyan, magenta, yellow, black)
 * model typical of printers and other paper-based output devices.
 *
 * @author John Hewson
 * @author Ben Litchfield
 */
public class PDDeviceCMYK extends PDDeviceColorSpace
{
    /**  The single instance of this class. */
    public static PDDeviceCMYK INSTANCE;
    static
    {
        INSTANCE = new PDDeviceCMYK();
    }

    private final PDColor initialColor = new PDColor(new float[] { 0, 0, 0, 1 }, this);
    private ICC_ColorSpace awtColorSpace;
    private volatile boolean initDone = false;
    private boolean usePureJavaCMYKConversion = false;

    protected PDDeviceCMYK()
    {
    }

    /**
     * Lazy load the ICC profile, because it's slow.
     * 
     * @throws IOException if the ICC profile could not be initialized
     */
    protected void init() throws IOException
    {
        // no need to synchronize this check as it is atomic
        if (initDone)
        {
            return;
        }
        synchronized (this)
        {
            // we might have been waiting for another thread, so check again
            if (initDone)
            {
                return;
            }
            // loads the ICC color profile for CMYK
            ICC_Profile iccProfile = getICCProfile();
            if (iccProfile == null)
            {
                throw new IOException("Default CMYK color profile could not be loaded");
            }
            awtColorSpace = new ICC_ColorSpace(iccProfile);

            // there is a JVM bug which results in a CMMException which appears to be a race
            // condition caused by lazy initialization of the color transform, so we perform
            // an initial color conversion while we're still in a static context, see PDFBOX-2184
            awtColorSpace.toRGB(new float[] { 0, 0, 0, 0 });
            usePureJavaCMYKConversion = System
                    .getProperty("org.apache.pdfbox.rendering.UsePureJavaCMYKConversion") != null;

            // Assignment to volatile must be the LAST statement in this block!
            initDone = true;
        }
    }

    protected ICC_Profile getICCProfile() throws IOException
    {
        // Adobe Acrobat uses "U.S. Web Coated (SWOP) v2" as the default
        // CMYK profile, however it is not available under an open license.
        // Instead, the "CGATS001Compat-v2-micro" is used, which is an open
        // alternative to the "U.S. Web Coated (SWOP) v2" profile.
        // https://github.com/saucecontrol/Compact-ICC-Profiles#cmyk
        String resourceName = "/org/apache/pdfbox/resources/icc/CGATS001Compat-v2-micro.icc";
        InputStream resourceAsStream = PDDeviceCMYK.class.getResourceAsStream(resourceName);
        if (resourceAsStream == null)
        {
            throw new IOException("resource '" + resourceName + "' not found");
        }    
        try (InputStream is = new BufferedInputStream(resourceAsStream))
        {
            return ICC_Profile.getInstance(is);
        }
    }

    @Override
    public String getName()
    {
        return COSName.DEVICECMYK.getName();
    }

    @Override
    public int getNumberOfComponents()
    {
        return 4;
    }

    @Override
    public float[] getDefaultDecode(int bitsPerComponent)
    {
        return new float[] { 0, 1, 0, 1, 0, 1, 0, 1 };
    }

    @Override
    public PDColor getInitialColor()
    {
        return initialColor;
    }

    @Override
    public float[] toRGB(float[] value) throws IOException
    {
        init();
        return awtColorSpace.toRGB(value);
    }

    @Override
    public BufferedImage toRawImage(WritableRaster raster) throws IOException
    {
        // Device CMYK is not specified, as its the colors of whatever device you use.
        // The user should fallback to the RGB image
        return null;
    }

    @Override
    public BufferedImage toRGBImage(WritableRaster raster) throws IOException
    {
        init();
        return toRGBImageAWT(raster, awtColorSpace);
    }

    @Override
    protected BufferedImage toRGBImageAWT(WritableRaster raster, ColorSpace colorSpace)
    {
        if (usePureJavaCMYKConversion)
        {
            BufferedImage dest = new BufferedImage(raster.getWidth(), raster.getHeight(),
                    BufferedImage.TYPE_INT_RGB);
            ColorSpace destCS = dest.getColorModel().getColorSpace();
            WritableRaster destRaster = dest.getRaster();
            float[] srcValues = new float[4];
            float[] lastValues = new float[] { -1.0f, -1.0f, -1.0f, -1.0f };
            float[] destValues = new float[3];
            int startX = raster.getMinX();
            int startY = raster.getMinY();
            int endX = raster.getWidth() + startX;
            int endY = raster.getHeight() + startY;
            for (int x = startX; x < endX; x++)
            {
                for (int y = startY; y < endY; y++)
                {
                    raster.getPixel(x, y, srcValues);
                    // check if the last value can be reused
                    if (!Arrays.equals(lastValues, srcValues))
                    {
                        lastValues[0] = srcValues[0];
                        srcValues[0] = srcValues[0] / 255f;

                        lastValues[1] = srcValues[1];
                        srcValues[1] = srcValues[1] / 255f;

                        lastValues[2] = srcValues[2];
                        srcValues[2] = srcValues[2] / 255f;

                        lastValues[3] = srcValues[3];
                        srcValues[3] = srcValues[3] / 255f;

                        // use CIEXYZ as intermediate format to optimize the color conversion
                        destValues = destCS.fromCIEXYZ(colorSpace.toCIEXYZ(srcValues));
                        for (int k = 0; k < destValues.length; k++)
                        {
                            destValues[k] = destValues[k] * 255f;
                        }
                    }
                    destRaster.setPixel(x, y, destValues);
                }
            }
            return dest;
        }
        else
        {
            return super.toRGBImageAWT(raster, colorSpace);
        }
    }
}
