/**
 * This work was created by participants in the DataONE project, and is
 * jointly copyrighted by participating institutions in DataONE. For 
 * more information on DataONE, see our web site at http://dataone.org.
 *
 *   Copyright ${year}
 *
 * 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.
 * 
 * $Id$
 */

package org.dataone.cn.batch.logging.listener;

import java.io.IOException;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;
import java.util.concurrent.BlockingQueue;

import org.apache.commons.codec.net.URLCodec;
import org.apache.log4j.Logger;
import org.apache.solr.client.solrj.SolrQuery;
import org.apache.solr.client.solrj.SolrServerException;
import org.apache.solr.client.solrj.impl.HttpSolrClient;
import org.apache.solr.client.solrj.response.QueryResponse;
import org.apache.solr.client.solrj.util.ClientUtils;
import org.dataone.cn.batch.logging.type.LogEntrySolrItem;
import org.dataone.cn.hazelcast.HazelcastClientFactory;
import org.dataone.configuration.Settings;
import org.dataone.service.types.v1.Identifier;
import org.dataone.service.types.v2.SystemMetadata;
import org.dataone.solr.client.solrj.impl.CommonsHttpClientProtocolRegistry;

import com.hazelcast.client.HazelcastClient;
import com.hazelcast.core.EntryEvent;
import com.hazelcast.core.EntryListener;
import com.hazelcast.core.IMap;
import org.dataone.cn.batch.logging.SolrClientManager;

/**
 * Access to Objects may change
 * Listen to the systemMetadata maps and if the accessibility of the object
 * has changed, then all log records associated with the object
 * must also change
 * 
 * All log records will need to be periodically swept for inconsistency
 * should this listener go down
 * 
 * @author waltz
 */
public class SystemMetadataEntryListener implements EntryListener<Identifier, SystemMetadata> {

    private static Logger logger = Logger.getLogger(SystemMetadataEntryListener.class.getName());
    private static HazelcastClient hzclient;
    private static final String HZ_SYSTEM_METADATA = Settings.getConfiguration().getString(
            "dataone.hazelcast.systemMetadata");
    private static final String HZ_LOGENTRY_TOPICNAME = Settings.getConfiguration().getString(
            "dataone.hazelcast.logEntryTopic");
    private IMap<Identifier, SystemMetadata> systemMetadata;
    private BlockingQueue<List<LogEntrySolrItem>> indexLogEntryQueue;
    private HttpSolrClient localhostSolrServer;
    //private LogAccessRestriction logAccessRestriction;
    private URLCodec urlCodec = new URLCodec("UTF-8");
    SolrClientManager solrClientManager = null;
    public SystemMetadataEntryListener() {
        //String cnURL = Settings.getConfiguration().getString("D1Client.CN_URL");
        //String localhostCNURL = cnURL.substring(0, cnURL.lastIndexOf("/cn"));
        //localhostCNURL += Settings.getConfiguration().getString("LogAggregator.solrUrlPath");

        String localhostCNURL = Settings.getConfiguration().getString("LogAggregator.solrUrl");

        localhostSolrServer = new HttpSolrClient(localhostCNURL);
        try {
            CommonsHttpClientProtocolRegistry.createInstance();
        } catch (Exception ex) {
            ex.printStackTrace();
            logger.error(ex.getMessage());
            throw new RuntimeException();
        }
        solrClientManager = SolrClientManager.getInstance();
    }

    public void start() {
        logger.info("starting systemMetadata entry listener...");
        logger.info("System Metadata value: " + HZ_SYSTEM_METADATA);

        hzclient = HazelcastClientFactory.getStorageClient();
        this.systemMetadata = hzclient.getMap(HZ_SYSTEM_METADATA);
        this.systemMetadata.addEntryListener(this, true);
        logger.info("System Metadata size: " + this.systemMetadata.size());
    }

    public void stop() {
        logger.info("stopping index task generator entry listener...");
        this.systemMetadata.removeEntryListener(this);
    }

    @Override
    public void entryUpdated(EntryEvent<Identifier, SystemMetadata> event) {
        boolean activateJob = Boolean.parseBoolean(Settings.getConfiguration().getString(
                "LogAggregator.active"));
        if (event.getKey() != null && event.getValue() != null && activateJob) {
            SystemMetadata systemMetadata = event.getValue();
            logger.trace("UPDATE EVENT - index task generator - system metadata callback invoked on pid: "
                    + event.getKey().getValue());
            List<LogEntrySolrItem> publishLogEntryList = retrieveLogEntries(event.getKey()
                    .getValue());
            if (!publishLogEntryList.isEmpty()) {
                processLogEntries(publishLogEntryList, systemMetadata);
            }
        }
    }

    @Override
    public void entryAdded(EntryEvent<Identifier, SystemMetadata> event) {
        boolean activateJob = Boolean.parseBoolean(Settings.getConfiguration().getString(
                "LogAggregator.active"));
        if (event.getKey() != null && event.getValue() != null & activateJob) {
            SystemMetadata systemMetadata = event.getValue();
            if (systemMetadata.getSerialVersion().longValue() == 1) {
                logger.trace("ADD EVENT - index task generator - system metadata callback invoked on pid: "
                        + event.getKey().getValue());
                List<LogEntrySolrItem> publishLogEntryList = retrieveLogEntries(event.getKey()
                        .getValue());
                if (!publishLogEntryList.isEmpty()) {
                    processLogEntries(publishLogEntryList, systemMetadata);
                }
            }
        }
    }

    private List<LogEntrySolrItem> retrieveLogEntries(String pid) {
        List<LogEntrySolrItem> completeLogEntrySolrItemList = new ArrayList<LogEntrySolrItem>();

        String escapedPID = ClientUtils.escapeQueryChars(pid);

        SolrQuery queryParams = new SolrQuery();
        queryParams.setQuery("pid:" + escapedPID);
        queryParams.setStart(0);
        queryParams.setRows(1000);

        QueryResponse queryResponse;
        try {

            queryResponse = localhostSolrServer.query(queryParams);

            List<LogEntrySolrItem> logEntrySolrItemList = queryResponse
                    .getBeans(LogEntrySolrItem.class);
            completeLogEntrySolrItemList.addAll(logEntrySolrItemList);
            int currentTotal = logEntrySolrItemList.size();
            long totalResults = queryResponse.getResults().getNumFound();
            if (currentTotal < totalResults) {
                do {
                    queryParams.setStart(currentTotal);
                    queryResponse = localhostSolrServer.query(queryParams);
                    logEntrySolrItemList = queryResponse.getBeans(LogEntrySolrItem.class);
                    completeLogEntrySolrItemList.addAll(logEntrySolrItemList);
                    currentTotal += logEntrySolrItemList.size();

                } while (currentTotal < totalResults);
            }
        } catch (IOException | SolrServerException ex) {
            logger.error(ex.getMessage(), ex);
        } 
//        logger.debug("returning # log entries to modify: " + completeLogEntrySolrItemList.size());
        return completeLogEntrySolrItemList;
    }

    private void processLogEntries(List<LogEntrySolrItem> logEntrySolrItemList,
            SystemMetadata systemMetadata) {

        String dbFilename = Settings.getConfiguration().getString("LogAggregator.geoIPdbName");
        Date now = new Date();

        //List<String> subjectsAllowedRead = logAccessRestriction.subjectsAllowedRead(systemMetadata);

        for (LogEntrySolrItem solrItem : logEntrySolrItemList) {
            /*
             * Fill in the solrItem fields for fields that are either obtained
             * from systemMetadata.
             */
            solrItem.updateSysmetaFields(systemMetadata);
            solrItem.setDateUpdated(now);
        }

        // publish 100 at a time, do not overwhelm the
        // network with massive packets, or too many small packets
        int startIndex = 0;
        int endIndex = 0;
        do {
            endIndex += 100;
            if (logEntrySolrItemList.size() < endIndex) {
                endIndex = logEntrySolrItemList.size();
            }
            List<LogEntrySolrItem> publishEntrySolrItemList = new ArrayList<LogEntrySolrItem>(100);
            publishEntrySolrItemList.addAll(logEntrySolrItemList.subList(startIndex, endIndex));

            try {
                localhostSolrServer.addBeans(publishEntrySolrItemList);
                localhostSolrServer.commit();
            } catch (IOException | SolrServerException ex) {
                logger.error("SystemMetadataEntryListener- "  + ex.getMessage(), ex);

            } 
            startIndex = endIndex;
        } while (endIndex < logEntrySolrItemList.size());
    }

    @Override
    public void entryEvicted(EntryEvent<Identifier, SystemMetadata> arg0) {
    }

    @Override
    public void entryRemoved(EntryEvent<Identifier, SystemMetadata> arg0) {
    }

}