/*

 * Copyright (c) 2005, 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

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package sun.swing;

import java.awt.Container;

import java.awt.Insets;

import javax.swing.*;

import javax.swing.LayoutStyle.ComponentPlacement;

import javax.swing.border.Border;

import javax.swing.plaf.UIResource;

/**

 * An implementation of <code>LayoutStyle</code> that returns 6 for related

 * components, otherwise 12.  This class also provides helper methods for

 * subclasses.

 *

 */

public class DefaultLayoutStyle extends LayoutStyle {

    private static final DefaultLayoutStyle INSTANCE =

            new DefaultLayoutStyle();

    public static LayoutStyle getInstance() {

        return INSTANCE;

    }

    @Override

    public int getPreferredGap(JComponent component1, JComponent component2,

            ComponentPlacement type, int position, Container parent) {

        if (component1 == null || component2 == null || type == null) {

            throw new NullPointerException();

        }

        checkPosition(position);

        if (type == ComponentPlacement.INDENT &&

                (position == SwingConstants.EAST ||

                 position == SwingConstants.WEST)) {

            int indent = getIndent(component1, position);

            if (indent > 0) {

                return indent;

            }

        }

        return (type == ComponentPlacement.UNRELATED) ? 12 : 6;

    }

    @Override

    public int getContainerGap(JComponent component, int position,

                               Container parent) {

        if (component == null) {

            throw new NullPointerException();

        }

        checkPosition(position);

        return 6;

    }

    /**

     * Returns true if the classes identify a JLabel and a non-JLabel

     * along the horizontal axis.

     */

    protected boolean isLabelAndNonlabel(JComponent c1, JComponent c2,

                                         int position) {

        if (position == SwingConstants.EAST ||

                position == SwingConstants.WEST) {

            boolean c1Label = (c1 instanceof JLabel);

            boolean c2Label = (c2 instanceof JLabel);

            return ((c1Label || c2Label) && (c1Label != c2Label));

        }

        return false;

    }

    /**

     * For some look and feels check boxs and radio buttons typically

     * don't paint the border, yet they have padding for a border.  Look

     * and feel guidelines generally don't include this space.  Use

     * this method to subtract this space from the specified

     * components.

     *

     * @param source First component

     * @param target Second component

     * @param position Position doing layout along.

     * @param offset Ideal offset, not including border/margin

     * @return offset - border/margin around the component.

     */

    protected int getButtonGap(JComponent source, JComponent target,

                               int position, int offset) {

        offset -= getButtonGap(source, position);

        if (offset > 0) {

            offset -= getButtonGap(target, flipDirection(position));

        }

        if (offset < 0) {

            return 0;

        }

        return offset;

    }

    /**

     * For some look and feels check boxs and radio buttons typically

     * don't paint the border, yet they have padding for a border.  Look

     * and feel guidelines generally don't include this space.  Use

     * this method to subtract this space from the specified

     * components.

     *

     * @param source Component

     * @param position Position doing layout along.

     * @param offset Ideal offset, not including border/margin

     * @return offset - border/margin around the component.

     */

    protected int getButtonGap(JComponent source, int position, int offset) {

        offset -= getButtonGap(source, position);

        return Math.max(offset, 0);

    }

    /**

     * If <code>c</code> is a check box or radio button, and the border is

     * not painted this returns the inset along the specified axis.

     */

    public int getButtonGap(JComponent c, int position) {

        String classID = c.getUIClassID();

        if ((classID == "CheckBoxUI" || classID == "RadioButtonUI") &&

                !((AbstractButton)c).isBorderPainted()) {

            Border border = c.getBorder();

            if (border instanceof UIResource) {

                return getInset(c, position);

            }

        }

        return 0;

    }

    private void checkPosition(int position) {

        if (position != SwingConstants.NORTH &&

                position != SwingConstants.SOUTH &&

                position != SwingConstants.WEST &&

                position != SwingConstants.EAST) {

            throw new IllegalArgumentException();

        }

    }

    protected int flipDirection(int position) {

        switch(position) {

        case SwingConstants.NORTH:

            return SwingConstants.SOUTH;

        case SwingConstants.SOUTH:

            return SwingConstants.NORTH;

        case SwingConstants.EAST:

            return SwingConstants.WEST;

        case SwingConstants.WEST:

            return SwingConstants.EAST;

        }

        assert false;

        return 0;

    }

    /**

     * Returns the amount to indent the specified component if it's

     * a JCheckBox or JRadioButton.  If the component is not a JCheckBox or

     * JRadioButton, 0 will be returned.

     */

    protected int getIndent(JComponent c, int position) {

        String classID = c.getUIClassID();

        if (classID == "CheckBoxUI" || classID == "RadioButtonUI") {

            AbstractButton button = (AbstractButton)c;

            Insets insets = c.getInsets();

            Icon icon = getIcon(button);

            int gap = button.getIconTextGap();

            if (isLeftAligned(button, position)) {

                return insets.left + icon.getIconWidth() + gap;

            } else if (isRightAligned(button, position)) {

                return insets.right + icon.getIconWidth() + gap;

            }

        }

        return 0;

    }

    private Icon getIcon(AbstractButton button) {

        Icon icon = button.getIcon();

        if (icon != null) {

            return icon;

        }

        String key = null;

        if (button instanceof JCheckBox) {

            key = "CheckBox.icon";

        } else if (button instanceof JRadioButton) {

            key = "RadioButton.icon";

        }

        if (key != null) {

            Object oIcon = UIManager.get(key);

            if (oIcon instanceof Icon) {

                return (Icon)oIcon;

            }

        }

        return null;

    }

    private boolean isLeftAligned(AbstractButton button, int position) {

        if (position == SwingConstants.WEST) {

            boolean ltr = button.getComponentOrientation().isLeftToRight();

            int hAlign = button.getHorizontalAlignment();

            return ((ltr && (hAlign == SwingConstants.LEFT ||

                             hAlign == SwingConstants.LEADING)) ||

                    (!ltr && (hAlign == SwingConstants.TRAILING)));

        }

        return false;

    }

    private boolean isRightAligned(AbstractButton button, int position) {

        if (position == SwingConstants.EAST) {

            boolean ltr = button.getComponentOrientation().isLeftToRight();

            int hAlign = button.getHorizontalAlignment();

            return ((ltr && (hAlign == SwingConstants.RIGHT ||

                             hAlign == SwingConstants.TRAILING)) ||

                    (!ltr && (hAlign == SwingConstants.LEADING)));

        }

        return false;

    }

    private int getInset(JComponent c, int position) {

        return getInset(c.getInsets(), position);

    }

    private int getInset(Insets insets, int position) {

        if (insets == null) {

            return 0;

        }

        switch(position) {

        case SwingConstants.NORTH:

            return insets.top;

        case SwingConstants.SOUTH:

            return insets.bottom;

        case SwingConstants.EAST:

            return insets.right;

        case SwingConstants.WEST:

            return insets.left;

        }

        assert false;

        return 0;

    }

}