Copyright (c) 2011, 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
/*******************************************************************************
 * Copyright (c) 2011, 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.core.internal.preferences;

import java.util.*;
import org.eclipse.core.runtime.ISafeRunnable;
import org.eclipse.core.runtime.SafeRunner;
import org.eclipse.core.runtime.preferences.AbstractPreferenceStorage;
import org.eclipse.core.runtime.preferences.IEclipsePreferences;
import org.eclipse.osgi.util.NLS;
import org.osgi.service.prefs.BackingStoreException;

public class ScopeDescriptor {

	String name;
	AbstractPreferenceStorage storage;
	Set<String> loadedNodes = Collections.synchronizedSet(new HashSet<String>());

	public ScopeDescriptor(AbstractPreferenceStorage storage) {
		super();
		this.storage = storage;
	}

	String getName() {
		return name;
	}

	/*
	 * For now the default behaviour is that we flush/load at the second level.
	 */
	IEclipsePreferences getLoadLevel(IEclipsePreferences node) {
		String path = node.absolutePath();
		int count = EclipsePreferences.getSegmentCount(path);
		// root or scope root
		if (count == 1 || count == 0)
			return null;
		// the load level we want
		if (count == 2)
			return node;
		for (int i = count; i > 2 && node.parent() != null; i--)
			node = (IEclipsePreferences) node.parent();
		return node;
	}

	String[] childrenNames(final String path) throws BackingStoreException {
		if (storage == null)
			return new String[0];
		final String[][] result = new String[1][];
		final BackingStoreException[] bse = new BackingStoreException[1];
		ISafeRunnable code = new ISafeRunnable() {
			@Override
			public void run() throws Exception {
				result[0] = storage.childrenNames(path);
			}

			@Override
			public void handleException(Throwable exception) {
				if (exception instanceof BackingStoreException)
					bse[0] = (BackingStoreException) exception;
				else
					bse[0] = new BackingStoreException(NLS.bind(PrefsMessages.childrenNames2, path), exception);
			}
		};
		SafeRunner.run(code);
		if (bse[0] != null)
			throw bse[0];
		return result[0] == null ? new String[0] : result[0];
	}

	Properties load(final String path) throws BackingStoreException {
		if (storage == null)
			return null;
		final Properties[] result = new Properties[1];
		final BackingStoreException[] bse = new BackingStoreException[1];
		ISafeRunnable code = new ISafeRunnable() {
			@Override
			public void run() throws Exception {
				result[0] = storage.load(path);
			}

			@Override
			public void handleException(Throwable exception) {
				if (exception instanceof BackingStoreException)
					bse[0] = (BackingStoreException) exception;
				else
					bse[0] = new BackingStoreException(NLS.bind(PrefsMessages.preferences_loadException, path), exception);
			}
		};
		SafeRunner.run(code);
		if (bse[0] != null)
			throw bse[0];
		return result[0] == null ? null : result[0];
	}

	void save(final String path, final Properties properties) throws BackingStoreException {
		if (storage == null)
			return;
		final BackingStoreException[] bse = new BackingStoreException[1];
		ISafeRunnable code = new ISafeRunnable() {
			@Override
			public void run() throws Exception {
				storage.save(path, properties);
			}

			@Override
			public void handleException(Throwable exception) {
				if (exception instanceof BackingStoreException)
					bse[0] = (BackingStoreException) exception;
				else
					bse[0] = new BackingStoreException(NLS.bind(PrefsMessages.preferences_saveException, path), exception);
			}
		};
		SafeRunner.run(code);
		if (bse[0] != null)
			throw bse[0];
	}

	boolean isAlreadyLoaded(String node) {
		return loadedNodes.contains(node);
	}

	void loaded(String node) {
		loadedNodes.add(node);
	}

	void removed(final String path) {
		if (storage == null)
			return;
		SafeRunner.run(new ISafeRunnable() {
			@Override
			public void run() throws Exception {
				storage.removed(path);
			}

			@Override
			public void handleException(Throwable exception) {
				// ignore here, error will be logged in saferunner
			}
		});
	}
}