/**
 * MIT License
 * Copyright (c) 2017 Apollo Zhu (朱智语).
 * <p>
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 * <p>
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 * <p>
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */
package io.github.apollozhu.swing;

import javax.swing.*;
import java.awt.*;
import java.beans.ConstructorProperties;

/**
 * A subclass of JButton with {@link #setBackground(Color)} working on macOS/OS X.
 *
 * @author Apollo Zhu
 *
 * @version 1.0
 */
@SuppressWarnings("serial")
public class AZJButton extends JButton {

    /**
     * Creates a button with no set text or icon.
     */
    public AZJButton() {
        super();
    }

    /**
     * Creates a button where properties are taken from the <code>Action</code>
     * supplied.
     *
     * @param a the <code>Action</code> used to specify the new button
     */
    public AZJButton(Action a) {
        super(a);
    }

    /**
     * Creates a button with an icon.
     *
     * @param icon the Icon image to display on the button
     */
    public AZJButton(Icon icon) {
        super(icon);
    }

    /**
     * Creates a button with text.
     *
     * @param text the text of the button
     */
    @ConstructorProperties({"text"})
    public AZJButton(String text) {
        super(text);
    }

    /**
     * Creates a button with initial text and an icon.
     *
     * @param text the text of the button
     * @param icon the Icon image to display on the button
     */
    public AZJButton(String text, Icon icon) {
        super(text, icon);
    }

    /** Selected menu item color from Apple's Developer Swatch. */
    protected static final Color SELECTED_MENU_ITEM_COLOR = new Color(3, 100, 236);

    /** Header color from Apple's Developer Swatch. */
    protected static final Color HEADER_COLOR = new Color(174, 174, 174);

    /** Keyboard focus indicator color from Apple's Developer Swatch. */
    protected static final Color KEYBOARD_FOCUS_INDICATOR_COLOR = new Color(76, 149, 255);

    /** Selected control color from Apple's Developer Swatch. */
    protected static final Color SELECTED_CONTROL_COLOR = new Color(164, 205, 255);

    /**
     * Check if UIManager is using Apple Aqua Look and Feel.
     *
     * @return true if current look and feel is aqua.
     */
    private boolean isAquaUI() {
        try {
            return getBorder().getClass().getName().contains("Aqua");
        } catch (Exception e) {
            return false;
        }
    }

    /**
     * Calls the super implementation, unless UIManager is using Apple Aqua Look
     * and Feel.
     *
     * If it is, and if border is required, and has a different background than
     * the default one, the button will be drawn differently to match the actual
     * look and feel for a button with background color on OS X Yosemite (10.10)
     * and other macOSs above.
     *
     * @param g the <code>Graphics</code> object to protect
     *
     * @see #setBackground(Color)
     */
    @Override
    public void paintComponent(Graphics g) {
        if (!isAquaUI()) {
            super.paintComponent(g);
            return;
        }

        final Color backgroundColor = getBackground(), foregroundColor = getForeground();
        final boolean hasCustomBackground = !backgroundColor.equals(UIManager.getColor("Button.background"));
        final boolean isBorderPainted = isBorderPainted();
        final boolean isOpaque = isOpaque();

        if (isBorderPainted && hasCustomBackground) {
            final boolean isPressed = getModel().isPressed();
            Insets i = getBorder().getBorderInsets(this);
            int r = 8, offset = i.top, x = offset, y = offset, w = getWidth() - 2 * offset,
                    h = getHeight() - offset - i.bottom;

            Graphics2D g2 = (Graphics2D) g;

            if (isPressed) {
                int midX = getWidth() / 2;
                g2.setPaint(new GradientPaint(midX, 0, KEYBOARD_FOCUS_INDICATOR_COLOR, midX, getHeight(), SELECTED_MENU_ITEM_COLOR));
                setForeground(Color.white);
            } else {
                g2.setColor(backgroundColor);
            }
            g2.fillRoundRect(x, y, w, h, r, r);

            g2.setColor(HEADER_COLOR);
            g2.drawRoundRect(x, y, w, h, r, r);

            if (isPressed || isFocusOwner()) {
                g2.setColor(SELECTED_CONTROL_COLOR);
                g2.setStroke(new BasicStroke(2));
                g2.drawRoundRect(x, y, w, h, r, r);
            }

            super.setBorderPainted(false);
            super.setOpaque(false);
        }

        super.paintComponent(g);
        super.setBorderPainted(isBorderPainted);
        super.setOpaque(isOpaque);
        super.setForeground(foregroundColor);
    }
}