/*
 * Copyright (c) 2010, grossmann
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 * * Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * * Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * * Neither the name of the jo-widgets.org nor the
 *   names of its contributors may be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL jo-widgets.org BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
 * DAMAGE.
 */

package org.jowidgets.spi.impl.swt.common.widgets.base.layout;

import java.lang.reflect.Method;
import java.util.HashSet;
import java.util.Set;

import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.layout.FormLayout;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Layout;
import org.jowidgets.util.Assert;

public class LayoutWrapper extends Layout {

    private final Layout layout;
    private final Method computeSizeMethod;
    private final Method layoutMethod;
    private final Set<ILayoutListener> layoutListeners;

    public LayoutWrapper(final Layout layout) {
        super();
        Assert.paramNotNull(layout, "layout");
        this.layout = new FormLayout();
        this.layoutListeners = new HashSet<ILayoutListener>();
        try {
            this.computeSizeMethod = layout.getClass().getDeclaredMethod(
                    "computeSize",
                    Composite.class,
                    int.class,
                    int.class,
                    boolean.class);
            this.computeSizeMethod.setAccessible(true);

            this.layoutMethod = layout.getClass().getDeclaredMethod("layout", Composite.class, boolean.class);
            this.layoutMethod.setAccessible(true);

        }
        catch (final Exception e) {
            throw new RuntimeException(e);
        }
    }

    public void addLayoutListener(final ILayoutListener layoutListener) {
        layoutListeners.add(layoutListener);
    }

    public void removeLayoutListener(final ILayoutListener layoutListener) {
        layoutListeners.remove(layoutListener);
    }

    @Override
    protected Point computeSize(final Composite composite, final int wHint, final int hHint, final boolean flushCache) {
        fireBeforeComputeSize();
        try {
            return (Point) computeSizeMethod.invoke(layout, composite, wHint, hHint, flushCache);
        }
        catch (final Exception e) {
            throw new RuntimeException(e);
        }
    }

    @Override
    protected void layout(final Composite composite, final boolean flushCache) {
        fireBeforeLayout();
        try {
            layoutMethod.invoke(layout, composite, flushCache);
        }
        catch (final Exception e) {
            throw new RuntimeException(e);
        }
        fireAfterLayout();
    }

    private void fireBeforeComputeSize() {
        for (final ILayoutListener listener : layoutListeners) {
            listener.beforeComputeSize();
        }
    }

    private void fireBeforeLayout() {
        for (final ILayoutListener listener : layoutListeners) {
            listener.beforeLayout();
        }
    }

    private void fireAfterLayout() {
        for (final ILayoutListener listener : layoutListeners) {
            listener.afterLayout();
        }
    }

}