/*******************************************************************************
 * Copyright (c) 2000, 2015 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.ui.internal;

import static org.eclipse.swt.events.SelectionListener.widgetSelectedAdapter;

import org.eclipse.jface.action.ContributionItem;
import org.eclipse.swt.SWT;
import org.eclipse.swt.widgets.Menu;
import org.eclipse.swt.widgets.MenuItem;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.ui.IWorkbench;
import org.eclipse.ui.IWorkbenchWindow;

/**
 * A dynamic menu item to switch to other opened workbench windows.
 */
public class SwitchToWindowMenu extends ContributionItem {
	private static final int MAX_TEXT_LENGTH = 40;

	private IWorkbenchWindow workbenchWindow;

	private boolean showSeparator;

	/**
	 * Creates a new instance of this class.
	 *
	 * @param window        the workbench window this action applies to
	 * @param showSeparator whether to add a separator in the menu
	 */
	public SwitchToWindowMenu(IWorkbenchWindow window, String id, boolean showSeparator) {
		super(id);
		this.workbenchWindow = window;
		this.showSeparator = showSeparator;
	}

	/**
	 * Returns the text for a window. This may be truncated to fit within the
	 * MAX_TEXT_LENGTH.
	 */
	private String calcText(int number, IWorkbenchWindow window) {
		String suffix = window.getShell().getText();
		if (suffix == null) {
			return null;
		}

		StringBuilder sb = new StringBuilder();
		if (number < 10) {
			sb.append('&');
		}
		sb.append(number);
		sb.append(' ');
		if (suffix.length() <= MAX_TEXT_LENGTH) {
			sb.append(suffix);
		} else {
			sb.append(suffix.substring(0, MAX_TEXT_LENGTH));
			sb.append("..."); //$NON-NLS-1$
		}
		return sb.toString();
	}

	/**
	 * Fills the given menu with menu items for all opened workbench windows.
	 */
	@Override
	public void fill(Menu menu, int index) {

		// Get workbench windows.
		IWorkbench workbench = workbenchWindow.getWorkbench();
		IWorkbenchWindow[] array = workbench.getWorkbenchWindows();
		// avoid showing the separator and list for 0 or 1 items
		if (array.length < 2) {
			return;
		}

		// Add separator.
		if (showSeparator) {
			new MenuItem(menu, SWT.SEPARATOR, index);
			++index;
		}

		// Add one item for each window.
		int count = 1;
		for (IWorkbenchWindow window : array) {
			// can encounter disposed shells if this update is in response to a shell
			// closing
			if (!window.getShell().isDisposed()) {
				String name = calcText(count, window);
				if (name != null) {
					MenuItem mi = new MenuItem(menu, SWT.RADIO, index);
					index++;
					count++;
					mi.setText(name);
					mi.addSelectionListener(widgetSelectedAdapter(e -> {
						Shell windowShell = window.getShell();
						if (windowShell.getMinimized()) {
							windowShell.setMinimized(false);
						}
						windowShell.setActive();
						windowShell.moveAbove(null);
					}));
					mi.setSelection(window == workbenchWindow);
				}
			}
		}
	}

	/**
	 * Overridden to always return true and force dynamic menu building.
	 */
	@Override
	public boolean isDirty() {
		return true;
	}

	/**
	 * Overridden to always return true and force dynamic menu building.
	 */
	@Override
	public boolean isDynamic() {
		return true;
	}

	@Override
	public void dispose() {
		workbenchWindow = null;
		super.dispose();
	}
}