/*******************************************************************************
 * Copyright (c) 2008 Code 9 Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     Code 9 Corporation - initial API and implementation
 *     Chris Aniszczyk <caniszczyk@gmail.com>
 *     Rafael Oliveira Nobrega <rafael.oliveira@gmail.com> - bug 242028
 *******************************************************************************/
package org.eclipse.pde.internal.ds.ui;

import org.eclipse.core.runtime.Assert;
import org.eclipse.jface.dialogs.Dialog;
import org.eclipse.jface.dialogs.IDialogConstants;
import org.eclipse.jface.layout.PixelConverter;
import org.eclipse.jface.resource.JFaceResources;
import org.eclipse.swt.SWT;
import org.eclipse.swt.dnd.DragSource;
import org.eclipse.swt.dnd.DropTarget;
import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.layout.GridData;
import org.eclipse.swt.widgets.Button;
import org.eclipse.swt.widgets.Caret;
import org.eclipse.swt.widgets.Control;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Menu;
import org.eclipse.swt.widgets.ScrollBar;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.swt.widgets.Widget;

/**
 * Utility class to simplify access to some SWT resources. 
 */
public class SWTUtil {

    /**
     * Returns the standard display to be used. The method first checks, if
     * the thread calling this method has an associated disaply. If so, this
     * display is returned. Otherwise the method returns the default display.
     */
    public static Display getStandardDisplay() {
        Display display;
        display = Display.getCurrent();
        if (display == null)
            display = Display.getDefault();
        return display;
    }

    /**
     * Returns the shell for the given widget. If the widget doesn't represent
     * a SWT object that manage a shell, <code>null</code> is returned.
     * 
     * @return the shell for the given widget
     */
    public static Shell getShell(Widget widget) {
        if (widget instanceof Control)
            return ((Control) widget).getShell();
        if (widget instanceof Caret)
            return ((Caret) widget).getParent().getShell();
        if (widget instanceof DragSource)
            return ((DragSource) widget).getControl().getShell();
        if (widget instanceof DropTarget)
            return ((DropTarget) widget).getControl().getShell();
        if (widget instanceof Menu)
            return ((Menu) widget).getParent().getShell();
        if (widget instanceof ScrollBar)
            return ((ScrollBar) widget).getParent().getShell();

        return null;
    }

    /**
     * Returns a width hint for a button control.
     */
    public static int getButtonWidthHint(Button button) {
        if (button.getFont().equals(JFaceResources.getDefaultFont()))
            button.setFont(JFaceResources.getDialogFont());
        PixelConverter converter = new PixelConverter(button);
        int widthHint = converter.convertHorizontalDLUsToPixels(IDialogConstants.BUTTON_WIDTH);
        return Math.max(widthHint, button.computeSize(SWT.DEFAULT, SWT.DEFAULT, true).x);
    }

    /**
     * Sets width and height hint for the button control.
     * <b>Note:</b> This is a NOP if the button's layout data is not
     * an instance of <code>GridData</code>.
     * 
     * @param   the button for which to set the dimension hint
     */
    public static void setButtonDimensionHint(Button button) {
        Dialog.applyDialogFont(button);
        Assert.isNotNull(button);
        Object gd = button.getLayoutData();
        if (gd instanceof GridData) {
            ((GridData) gd).widthHint = getButtonWidthHint(button);
        }
    }

    public static void setDialogSize(Dialog dialog, int width, int height) {
        Point computedSize = dialog.getShell().computeSize(SWT.DEFAULT, SWT.DEFAULT);
        width = Math.max(computedSize.x, width);
        height = Math.max(computedSize.y, height);
        dialog.getShell().setSize(width, height);
    }
}