/*******************************************************************************
 * Copyright (c) 2000, 2009 IBM Corporation and others.
 *
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.search.internal.ui.util;

import org.eclipse.swt.SWT;
import org.eclipse.swt.dnd.DragSource;
import org.eclipse.swt.dnd.DropTarget;
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.Table;
import org.eclipse.swt.widgets.Widget;

import org.eclipse.core.runtime.Assert;

import org.eclipse.jface.dialogs.IDialogConstants;
import org.eclipse.jface.layout.PixelConverter;
import org.eclipse.jface.resource.JFaceResources;


/**
 * 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.
	 * @return Returns the standard display to be used.
	 */
	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.
	 *
	 * @param widget The widget to get the shell for
	 * @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.
	 * @param button The button to calculate the width for
	 * @return The width of the button
	 */
	public static int getButtonWidthHint(Button button) {
		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 button	the button for which to set the dimension hint
	 */
	public static void setButtonDimensionHint(Button button) {
		Assert.isNotNull(button);
		Object gd= button.getLayoutData();
		if (gd instanceof GridData) {
			((GridData)gd).widthHint= getButtonWidthHint(button);
			((GridData)gd).horizontalAlignment = GridData.FILL;
		}
	}

	public static int getTableHeightHint(Table table, int rows) {
		if (table.getFont().equals(JFaceResources.getDefaultFont()))
			table.setFont(JFaceResources.getDialogFont());
		int result= table.getItemHeight() * rows + table.getHeaderHeight();
		if (table.getLinesVisible())
			result+= table.getGridLineWidth() * (rows - 1);
		return result;
	}


}
