/*
 * Copyright (c) 2013, 2014, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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package sun.awt.image;

import java.awt.Image;
import java.awt.image.ImageObserver;
import java.awt.image.MultiResolutionImage;
import java.util.List;
import java.util.function.Function;
import java.util.stream.Collectors;
import sun.awt.SoftCache;

public class MultiResolutionToolkitImage extends ToolkitImage implements MultiResolutionImage {

    final List<ResolutionVariantItem> resolutionVariants;

    public MultiResolutionToolkitImage(Image baseImage,
            List<ResolutionVariantItem> resolutionVariants) {
        super(baseImage.getSource());
        this.resolutionVariants = resolutionVariants;
    }

    @Override
    public Image getResolutionVariant(double destWidth, double destHeight) {
        return getResolutionVariantItem(destWidth, destHeight).getImage();
    }

    public ResolutionVariantItem getResolutionVariantItem(
            double destWidth, double destHeight) {
        checkSize(destWidth, destHeight);
        int baseWidth = getWidth();
        int baseHeight = getHeight();

        for (ResolutionVariantItem rvItem : resolutionVariants) {
            double sx = rvItem.getScaleX();
            double sy = rvItem.getScaleY();
            if (destWidth <= baseWidth * sx && destHeight <= baseHeight * sy) {
                return rvItem;
            }
        }

        return resolutionVariants.get(resolutionVariants.size() - 1);
    }

    public static Image map(MultiResolutionToolkitImage mrImage,
                            Function<Image, Image> mapper) {
        Image baseImage = mapper.apply(mrImage);
        List<ResolutionVariantItem> rvItems = mrImage.resolutionVariants.stream()
                .map(new RVItemMapper(mapper))
                .collect(Collectors.toList());

        return new MultiResolutionToolkitImage(baseImage, rvItems);
    }

    private static void checkSize(double width, double height) {
        if (width <= 0 || height <= 0) {
            throw new IllegalArgumentException(String.format(
                    "Width (%s) or height (%s) cannot be <= 0", width, height));
        }

        if (!Double.isFinite(width) || !Double.isFinite(height)) {
            throw new IllegalArgumentException(String.format(
                    "Width (%s) or height (%s) is not finite", width, height));
        }
    }

    @Override
    public List<Image> getResolutionVariants() {
        return resolutionVariants.stream()
                .map(rvItem -> rvItem.getImage())
                .collect(Collectors.toList());
    }

    public List<ResolutionVariantItem> getResolutionVariantItems() {
        return resolutionVariants;
    }

    private static final int BITS_INFO = ImageObserver.SOMEBITS
            | ImageObserver.FRAMEBITS | ImageObserver.ALLBITS;

    private static class ObserverCache {

        @SuppressWarnings("deprecation")
        static final SoftCache INSTANCE = new SoftCache();
    }

    public static ImageObserver getResolutionVariantObserver(
            final Image image, final ImageObserver observer,
            final double scaleX, final double scaleY,
            boolean concatenateInfo) {

        if (observer == null) {
            return null;
        }

        synchronized (ObserverCache.INSTANCE) {

            Object key = new ObserverKey(observer, scaleX, scaleY);
            ImageObserver o = (ImageObserver) ObserverCache.INSTANCE.get(key);

            if (o == null) {

                o = (Image resolutionVariant, int flags,
                        int x, int y, int width, int height) -> {

                            if ((flags & (ImageObserver.WIDTH | BITS_INFO)) != 0) {
                                width = (int) Math.ceil(width / scaleX);
                            }

                            if ((flags & (ImageObserver.HEIGHT | BITS_INFO)) != 0) {
                                height = (int) Math.ceil(height / scaleY);
                            }

                            if ((flags & BITS_INFO) != 0) {
                                x = (int) Math.floor(x / scaleX);
                                y = (int) Math.floor(y / scaleY);
                            }

                            if(concatenateInfo){
                                flags &= ((ToolkitImage) image).
                                        getImageRep().check(null);
                            }

                            return observer.imageUpdate(
                                    image, flags, x, y, width, height);
                        };

                ObserverCache.INSTANCE.put(key, o);
            }
            return o;
        }
    }

    public static class ResolutionVariantItem {

        final Image image;
        final double scaleX;
        final double scaleY;

        public ResolutionVariantItem(Image image, double scaleX, double scaleY) {
            this.image = image;
            this.scaleX = scaleX;
            this.scaleY = scaleY;
        }

        public Image getImage() {
            return image;
        }

        public double getScaleX() {
            return scaleX;
        }

        public double getScaleY() {
            return scaleY;
        }

        public ResolutionVariantItem map(Function<Image, Image> mapper) {
            return new ResolutionVariantItem(mapper.apply(image), scaleX, scaleY);
        }
    }

    static class RVItemMapper
            implements Function<ResolutionVariantItem, ResolutionVariantItem> {

        final Function<Image, Image> mapper;

        public RVItemMapper(Function<Image, Image> mapper) {
            this.mapper = mapper;
        }

        @Override
        public ResolutionVariantItem apply(ResolutionVariantItem rvItem) {
            return new ResolutionVariantItem(mapper.apply(rvItem.getImage()),
                    rvItem.getScaleX(), rvItem.getScaleY());
        }
    }

    static class ObserverKey {

        final ImageObserver observer;
        final double scaleX;
        final double scaleY;

        public ObserverKey(ImageObserver observer, double scaleX, double scaleY) {
            this.observer = observer;
            this.scaleX = scaleX;
            this.scaleY = scaleY;
        }

        @Override
        public boolean equals(Object obj) {
            if (this == obj) {
                return true;
            }

            if (!(obj instanceof ObserverKey)) {
                return false;
            }

            ObserverKey observerKey = (ObserverKey) obj;
            return scaleX == observerKey.scaleX
                    && scaleY == observerKey.scaleY
                    && observer.equals(observerKey.observer);
        }

        @Override
        public int hashCode() {
            int hash = observer.hashCode();
            hash = 31 * hash + Double.hashCode(scaleX);
            hash = 31 * hash + Double.hashCode(scaleY);
            return hash;
        }
    }
}