/*
 * Copyright 2015-2024 MicroEJ Corp. All rights reserved.
 * This library is provided in source code for use, modification and test, subject to license terms.
 * Any modification of the source code will break MicroEJ Corp. warranties on the whole library.
 */
package ej.mwt.style.background;

import ej.annotation.Nullable;
import ej.microui.display.GraphicsContext;
import ej.microui.display.Image;
import ej.microui.display.Painter;
import ej.mwt.util.Alignment;

/**
 * Draws an image on the background.
 */
public class ImageBackground implements Background {

    /**
     * Creates an image background aligned on the top-left corner.
     *
     * @param image
     *            the background image.
     */
    public ImageBackground(Image image) {
        this(image, Alignment.LEFT, Alignment.TOP);
    }

    /**
     * Creates an image background specifying its alignment.
     *
     * @param image
     *            the background image.
     * @param horizontalAlignment
     *            the horizontal alignment.
     * @param verticalAlignment
     *            the vertical alignment.
     * @throws IllegalArgumentException
     *             if the horizontal or vertical alignment is not valid.
     * @see Alignment#validateHorizontalAlignment(int)
     * @see Alignment#validateVerticalAlignment(int)
     */
    public ImageBackground(Image image, int horizontalAlignment, int verticalAlignment) {
        Alignment.validateHorizontalAlignment(horizontalAlignment);
        Alignment.validateVerticalAlignment(verticalAlignment);
        this.image = image;
        this.horizontalAlignment = (byte) horizontalAlignment;
        this.verticalAlignment = (byte) verticalAlignment;
    }

    @Override
    public boolean isTransparent(int width, int height) {
        Image image = this.image;
        return (image.isTransparent() || image.getWidth() < width || image.getHeight() < height);
    }

    @Override
    public void apply(GraphicsContext g, int width, int height) {
        // draw image
        Image image = this.image;
        int x = Alignment.computeLeftX(image.getWidth(), 0, width, this.horizontalAlignment);
        int y = Alignment.computeTopY(image.getHeight(), 0, height, this.verticalAlignment);
        Painter.drawImage(g, image, x, y);
        // remove background color
        g.removeBackgroundColor();
    }

    @Override
    public boolean equals(@Nullable Object obj) {
        if (obj != null && getClass() == obj.getClass()) {
            ImageBackground background = (ImageBackground) obj;
            return this.image == background.image && this.horizontalAlignment == background.horizontalAlignment && this.verticalAlignment == background.verticalAlignment;
        }
        return false;
    }

    @Override
    public int hashCode() {
        // don't call this.image.hashCode() to avoid embedding the hashCode() method of every class (M0081MEJA-1240)
        return this.horizontalAlignment * this.verticalAlignment;
    }
}