/*

 * Copyright (c) 2015, 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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 * questions.

 */

package java.awt.image;

import java.awt.Image;

import java.util.List;

import java.util.Arrays;

import java.util.Collections;

import java.util.Objects;

/**

 * This class is an array-based implementation of

 * the {@code AbstractMultiResolutionImage} class.

 *

 * This class will implement the

 * {@code getResolutionVariant(double destImageWidth, double destImageHeight)}

 * method using a simple algorithm which will return the first image variant

 * in the array that is large enough to satisfy the rendering request. The

 * last image in the array will be returned if no suitable image is found

 * that is as large as the rendering request.

 * <p>

 * For best effect the array of images should be sorted with each image being

 * both wider and taller than the previous image.  The base image need not be

 * the first image in the array. No exception will be thrown if the images

 * are not sorted as suggested.

 *

 * @see java.awt.Image

 * @see java.awt.image.MultiResolutionImage

 * @see java.awt.image.AbstractMultiResolutionImage

 *

 * @since 9

 */

public class BaseMultiResolutionImage extends AbstractMultiResolutionImage {

    private final int baseImageIndex;

    private final Image[] resolutionVariants;

    /**

     * Creates a multi-resolution image with the given resolution variants.

     * The first resolution variant is used as the base image.

     *

     * @param resolutionVariants array of resolution variants sorted by image size

     * @throws IllegalArgumentException if null or zero-length array is passed

     * @throws NullPointerException if the specified {@code resolutionVariants}

     *          contains one or more null elements

     *

     * @since 9

     */

    public BaseMultiResolutionImage(Image... resolutionVariants) {

        this(0, resolutionVariants);

    }

    /**

     * Creates a multi-resolution image with the given base image index and

     * resolution variants.

     *

     * @param baseImageIndex the index of base image in the resolution variants

     *        array

     * @param resolutionVariants array of resolution variants sorted by image size

     * @throws IllegalArgumentException if null or zero-length array is passed

     * @throws NullPointerException if the specified {@code resolutionVariants}

     *          contains one or more null elements

     * @throws IndexOutOfBoundsException if {@code baseImageIndex} is

     *          negative or greater than or equal to {@code resolutionVariants}

     *          length.

     *

     * @since 9

     */

    public BaseMultiResolutionImage(int baseImageIndex,

                                    Image... resolutionVariants) {

        if (resolutionVariants == null || resolutionVariants.length == 0) {

            throw new IllegalArgumentException(

                    "Null or zero-length array is passed");

        }

        if (baseImageIndex < 0 || baseImageIndex >= resolutionVariants.length) {

            throw new IndexOutOfBoundsException("Invalid base image index: "

                    + baseImageIndex);

        }

        this.baseImageIndex = baseImageIndex;

        this.resolutionVariants = Arrays.copyOf(resolutionVariants,

                                                resolutionVariants.length);

        for (Image resolutionVariant : this.resolutionVariants) {

            Objects.requireNonNull(resolutionVariant,

                                   "Resolution variant can't be null");

        }

    }

    @Override

    public Image getResolutionVariant(double destImageWidth,

                                      double destImageHeight) {

        checkSize(destImageWidth, destImageHeight);

        for (Image rvImage : resolutionVariants) {

            if (destImageWidth <= rvImage.getWidth(null)

                    && destImageHeight <= rvImage.getHeight(null)) {

                return rvImage;

            }

        }

        return resolutionVariants[resolutionVariants.length - 1];

    }

    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 Collections.unmodifiableList(Arrays.asList(resolutionVariants));

    }

    @Override

    protected Image getBaseImage() {

        return resolutionVariants[baseImageIndex];

    }

}