/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.apache.sling.jcr.oak.server.it;

import java.util.Collections;
import java.util.HashSet;
import java.util.Hashtable;
import java.util.Set;

import org.osgi.framework.BundleContext;
import org.osgi.framework.ServiceRegistration;
import org.osgi.service.event.Event;
import org.osgi.service.event.EventConstants;
import org.osgi.service.event.EventHandler;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/** Keep track of OSGi events received on a given topic */
public class ResourceEventListener implements EventHandler {

    private final Logger log = LoggerFactory.getLogger(getClass());
    private final Set<String> paths = new HashSet<String>();

    ServiceRegistration register(BundleContext ctx, String osgiEventTopic) {
        final Hashtable<String, Object> props = new Hashtable<String, Object>();
        props.put(EventConstants.EVENT_TOPIC, osgiEventTopic);
        return ctx.registerService(EventHandler.class.getName(), this, props);
    }

    @Override
    public void handleEvent(Event event) {
        final String path = (String) event.getProperty("path");
        if(path != null) {
            final int n = paths.size();
            synchronized (paths) {
                if(n % 1000 == 0) {
                    log.info("Got events for {} paths so far, last path={}", n, path);
                }
                paths.add(path);
            }
        }
    }

    void clear() {
        synchronized (paths) {
            paths.clear();
        }
    }

    Set<String> getPaths() {
        synchronized (paths) {
            return Collections.unmodifiableSet(paths);
        }
    }
}