/*******************************************************************************
 * Copyright (c) 2007, 2010 Intel 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:
 * Intel Corporation - Initial API and implementation
 *******************************************************************************/
package org.eclipse.cdt.managedbuilder.internal.core;

import java.util.List;
import java.util.concurrent.CopyOnWriteArrayList;

import org.eclipse.cdt.managedbuilder.core.IHoldsOptions;
import org.eclipse.cdt.managedbuilder.core.IOption;
import org.eclipse.cdt.managedbuilder.core.IResourceInfo;

public class NotificationManager /*implements ISettingsChangeListener */ {
	private static NotificationManager fInstance;
	private List<ISettingsChangeListener> fListeners;

	private NotificationManager() {
		fListeners = new CopyOnWriteArrayList<ISettingsChangeListener>();
	}

	public static NotificationManager getInstance() {
		if (fInstance == null)
			fInstance = new NotificationManager();
		return fInstance;
	}

	public void optionRemoved(IResourceInfo rcInfo, IHoldsOptions holder, IOption option) {
		SettingsChangeEvent event = createOptionRemovedEvent(rcInfo, holder, option);
		notifyListeners(event);
	}

	public void optionChanged(IResourceInfo rcInfo, IHoldsOptions holder, IOption option, Object oldValue) {
		SettingsChangeEvent event = createOptionChangedEvent(rcInfo, holder, option, oldValue);
		notifyListeners(event);
	}

	private void notifyListeners(SettingsChangeEvent event) {
		for (ISettingsChangeListener listener : fListeners)
			listener.settingsChanged(event);
	}

	private static SettingsChangeEvent createOptionChangedEvent(IResourceInfo rcInfo, IHoldsOptions holder,
			IOption option, Object oldValue) {
		return new SettingsChangeEvent(SettingsChangeEvent.CHANGED, rcInfo, holder, option, oldValue);
	}

	private static SettingsChangeEvent createOptionRemovedEvent(IResourceInfo rcInfo, IHoldsOptions holder,
			IOption option) {
		return new SettingsChangeEvent(SettingsChangeEvent.REMOVED, rcInfo, holder, option, null);
	}

	public void subscribe(ISettingsChangeListener listener) {
		fListeners.add(listener);
	}

	public void unsubscribe(ISettingsChangeListener listener) {
		fListeners.remove(listener);
	}

}