/**
 * 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.rya.indexing.geotemporal.mongo;

import static com.google.common.base.Preconditions.checkArgument;
import static com.google.common.base.Preconditions.checkState;
import static java.util.Objects.requireNonNull;

import java.io.IOException;
import java.util.Optional;
import java.util.concurrent.atomic.AtomicReference;
import java.util.regex.Matcher;

import org.apache.hadoop.conf.Configuration;
import org.apache.log4j.Logger;
import org.apache.rya.api.domain.RyaStatement;
import org.apache.rya.api.domain.RyaURI;
import org.apache.rya.api.resolver.RyaToRdfConversions;
import org.apache.rya.indexing.GeoConstants;
import org.apache.rya.indexing.TemporalInstant;
import org.apache.rya.indexing.TemporalInstantRfc3339;
import org.apache.rya.indexing.TemporalInterval;
import org.apache.rya.indexing.accumulo.ConfigUtils;
import org.apache.rya.indexing.accumulo.geo.GeoParseUtils;
import org.apache.rya.indexing.geotemporal.GeoTemporalIndexer;
import org.apache.rya.indexing.geotemporal.model.Event;
import org.apache.rya.indexing.geotemporal.storage.EventStorage;
import org.apache.rya.indexing.mongodb.AbstractMongoIndexer;
import org.apache.rya.indexing.mongodb.IndexingException;
import org.apache.rya.indexing.mongodb.geo.GmlParser;
import org.apache.rya.mongodb.StatefulMongoDBRdfConfiguration;
import org.joda.time.DateTime;
import org.openrdf.model.Statement;
import org.openrdf.model.URI;

import com.vividsolutions.jts.geom.Geometry;
import com.vividsolutions.jts.io.ParseException;

/**
 * Indexer that stores 2 separate statements as one 'Event' entity.
 * <p>
 * The statements are required to have the same subject, one must be
 * a Geo based statement and the other a temporal based statement.
 * <p>
 * This indexer is later used when querying for geo/temporal statements
 * in the format of:
 * <pre>
 * {@code
 * QUERY PARAMS
 *   ?SomeSubject geo:predicate ?Location
 *   ?SomeSubject time:predicate ?Time
 *   Filter(?Location, geoFunction())
 *   Filter(?Time, temporalFunction())
 * }
 *
 * The number of filters is not strict, but there must be at least one
 * query pattern for geo and one for temporal as well as at least one
 * filter for each type.
 */
public class MongoGeoTemporalIndexer extends AbstractMongoIndexer<GeoTemporalMongoDBStorageStrategy> implements GeoTemporalIndexer {
    private static final Logger LOG = Logger.getLogger(MongoGeoTemporalIndexer.class);
    public static final String GEO_TEMPORAL_COLLECTION = "geo_temporal";

    private final AtomicReference<EventStorage> events = new AtomicReference<>();

    @Override
    public void init() {
        initCore();
        events.set(getEventStorage());

        predicates = ConfigUtils.getGeoPredicates(conf);
        predicates.addAll(ConfigUtils.getTemporalPredicates(conf));
        storageStrategy = new GeoTemporalMongoDBStorageStrategy();
    }

    @Override
    public void setConf(final Configuration conf) {
        requireNonNull(conf);
        checkArgument(conf instanceof StatefulMongoDBRdfConfiguration,
                "The configuration must be of type StatefulMongoDBRdfConfiguration but you provided: "
                        + conf.getClass().getSimpleName());
        super.conf = (StatefulMongoDBRdfConfiguration) conf;
    }

    @Override
    public void storeStatement(final RyaStatement ryaStatement) throws IOException {
        requireNonNull(ryaStatement);

        try {
            updateEvent(ryaStatement.getSubject(), ryaStatement);
        } catch (IndexingException | ParseException e) {
            throw new IOException("Failed to update the Entity index.", e);
        }
    }

    @Override
    public void deleteStatement(final RyaStatement statement) throws IOException {
        requireNonNull(statement);
        final RyaURI subject = statement.getSubject();
        try {
            final EventStorage eventStore = events.get();
            checkState(events != null, "Must set this indexers configuration before storing statements.");

            new EventUpdater(eventStore).update(subject, old -> {
                final Event.Builder updated;
                if(!old.isPresent()) {
                    return Optional.empty();
                } else {
                    updated = Event.builder(old.get());
                }

                final Event currentEvent = updated.build();
                final URI pred = statement.getObject().getDataType();
                if((pred.equals(GeoConstants.GEO_AS_WKT) || pred.equals(GeoConstants.GEO_AS_GML) ||
                   pred.equals(GeoConstants.XMLSCHEMA_OGC_WKT) || pred.equals(GeoConstants.XMLSCHEMA_OGC_GML))
                   && currentEvent.getGeometry().isPresent()) {
                    //is geo and needs to be removed.
                    try {
                        if(currentEvent.getGeometry().get().equals(GeoParseUtils.getGeometry(RyaToRdfConversions.convertStatement(statement), new GmlParser()))) {
                            updated.setGeometry(null);
                        }
                    } catch (final Exception e) {
                        LOG.debug("Unable to parse the stored geometry.");
                    }
                } else {
                    //is time
                    final String dateTime = statement.getObject().getData();
                    final Matcher matcher = TemporalInstantRfc3339.PATTERN.matcher(dateTime);
                    if (matcher.find()) {
                        final TemporalInterval interval = TemporalInstantRfc3339.parseInterval(dateTime);
                        if(currentEvent.getInterval().get().equals(interval)) {
                            updated.setTemporalInterval(null);
                        }
                    } else {
                        final TemporalInstant instant = new TemporalInstantRfc3339(DateTime.parse(dateTime));
                        if(currentEvent.getInstant().get().equals(instant)) {
                            updated.setTemporalInstant(null);
                        }
                    }
                }
                return Optional.of(updated.build());
            });
        } catch (final IndexingException e) {
            throw new IOException("Failed to update the Entity index.", e);
        }
    }

    private void updateEvent(final RyaURI subject, final RyaStatement statement) throws IndexingException, ParseException {
        final EventStorage eventStore = events.get();
        checkState(events != null, "Must set this indexers configuration before storing statements.");

        new EventUpdater(eventStore).update(subject, old -> {
            final Event.Builder updated;
            if(!old.isPresent()) {
                updated = Event.builder()
                    .setSubject(subject);
            } else {
                updated = Event.builder(old.get());
            }

            final URI pred = statement.getObject().getDataType();
            if(pred.equals(GeoConstants.GEO_AS_WKT) || pred.equals(GeoConstants.GEO_AS_GML) ||
               pred.equals(GeoConstants.XMLSCHEMA_OGC_WKT) || pred.equals(GeoConstants.XMLSCHEMA_OGC_GML)) {
                //is geo
                try {
                    final Statement geoStatement = RyaToRdfConversions.convertStatement(statement);
                    final Geometry geometry = GeoParseUtils.getGeometry(geoStatement, new GmlParser());
                    updated.setGeometry(geometry);
                } catch (final ParseException e) {
                    LOG.error(e.getMessage(), e);
                }
            } else {
                //is time
                final String dateTime = statement.getObject().getData();
                final Matcher matcher = TemporalInstantRfc3339.PATTERN.matcher(dateTime);
                if (matcher.find()) {
                    final TemporalInterval interval = TemporalInstantRfc3339.parseInterval(dateTime);
                    updated.setTemporalInterval(interval);
                } else {
                    final TemporalInstant instant = new TemporalInstantRfc3339(DateTime.parse(dateTime));
                    updated.setTemporalInstant(instant);
                }
            }
            return Optional.of(updated.build());
        });
    }

    @Override
    public String getCollectionName() {
        return ConfigUtils.getTablePrefix(conf)  + GEO_TEMPORAL_COLLECTION;
    }

    @Override
    public EventStorage getEventStorage() {
        requireNonNull(conf);

        if(events.get() != null) {
            return events.get();
        }

        events.set(new MongoEventStorage(conf.getMongoClient(), conf.getRyaInstanceName()));
        return events.get();
    }
}