/*
 * Copyright (C) 2007-2012 Argeo GmbH
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *         http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.argeo.slc.repo;

import java.util.ArrayList;
import java.util.List;

import javax.jcr.Node;
import javax.jcr.Repository;
import javax.jcr.RepositoryException;
import javax.jcr.Session;
import javax.jcr.observation.Event;
import javax.jcr.observation.EventIterator;
import javax.jcr.observation.EventListener;

import org.argeo.jcr.JcrUtils;
import org.argeo.slc.SlcException;

/** Repository backend, maintain the JCR repository, mainly through listeners */
public class RepoIndexer {

	private Repository jcrRepository;
	private String workspace = null;

	// Internal
	private Session adminSession;
	private FilesListener artifactListener;

	/** order may be important */
	private List<NodeIndexer> nodeIndexers = new ArrayList<NodeIndexer>();

	public void init() {
		try {
			adminSession = jcrRepository.login(workspace);
			artifactListener = new FilesListener();
			adminSession
					.getWorkspace()
					.getObservationManager()
					.addEventListener(artifactListener, Event.NODE_ADDED, "/",
							true, null, null, true);
		} catch (RepositoryException e) {
			throw new SlcException("Cannot initialize repository backend", e);
		}
	}

	public void destroy() {
		JcrUtils.logoutQuietly(adminSession);
	}

	public void setJcrRepository(Repository jcrRepository) {
		this.jcrRepository = jcrRepository;
	}

	public void setNodeIndexers(List<NodeIndexer> nodeIndexers) {
		this.nodeIndexers = nodeIndexers;
	}

	public void setWorkspace(String workspace) {
		this.workspace = workspace;
	}

	class FilesListener implements EventListener {

		public void onEvent(EventIterator events) {
			while (events.hasNext()) {
				Event event = events.nextEvent();
				try {
					String newNodePath = event.getPath();
					Node newNode = null;
					for (NodeIndexer nodeIndexer : nodeIndexers) {
						try {
							if (nodeIndexer.support(newNodePath)) {
								if (newNode == null)
									newNode = adminSession.getNode(newNodePath);
								nodeIndexer.index(newNode);
							}
						} catch (RuntimeException e) {
							e.printStackTrace();
							throw e;
						}
					}
					if (newNode != null)
						adminSession.save();
				} catch (RepositoryException e) {
					throw new SlcException("Cannot process event " + event, e);
				} finally {
					JcrUtils.discardQuietly(adminSession);
				}
			}

		}

	}

}