/*
 * Licensed to STRATIO (C) under one or more contributor license agreements.
 * See the NOTICE file distributed with this work for additional information
 * regarding copyright ownership.  The STRATIO (C) 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 com.stratio.cassandra.lucene;

import com.stratio.cassandra.lucene.cache.SearchCacheUpdater;
import com.stratio.cassandra.lucene.index.DocumentIterator;
import org.apache.cassandra.db.ColumnFamilyStore;
import org.apache.cassandra.db.DecoratedKey;
import org.apache.cassandra.db.ReadCommand;
import org.apache.cassandra.db.ReadOrderGroup;
import org.apache.cassandra.db.filter.ClusteringIndexFilter;
import org.apache.cassandra.db.rows.UnfilteredRowIterator;
import org.apache.cassandra.utils.Pair;
import org.apache.lucene.document.Document;
import org.apache.lucene.search.ScoreDoc;

/**
 * {@link IndexReader} for skinny rows.
 *
 * @author Andres de la Pena {@literal <adelapena@stratio.com>}
 */
public class IndexReaderSkinny extends IndexReader {

    private final IndexServiceSkinny service;
    private final SearchCacheUpdater cacheUpdater;

    /**
     * Constructor taking the Cassandra read data and the Lucene results iterator.
     *
     * @param service the index service
     * @param command the read command
     * @param table the base table
     * @param orderGroup the order group of the read operation
     * @param documents the documents iterator
     * @param cacheUpdater the search cache updater
     */
    public IndexReaderSkinny(IndexServiceSkinny service,
                             ReadCommand command,
                             ColumnFamilyStore table,
                             ReadOrderGroup orderGroup,
                             DocumentIterator documents,
                             SearchCacheUpdater cacheUpdater) {
        super(command, table, orderGroup, documents);
        this.service = service;
        this.cacheUpdater = cacheUpdater;
    }

    @Override
    protected boolean prepareNext() {
        while (next == null && documents.hasNext()) {
            Pair<Document, ScoreDoc> nextDoc = documents.next();
            DecoratedKey key = service.decoratedKey(nextDoc.left);
            ClusteringIndexFilter filter = command.clusteringIndexFilter(key);
            UnfilteredRowIterator data = read(key, filter);
            if (data != null) {
                if (data.isEmpty()) {
                    data.close();
                } else {
                    next = data;
                    cacheUpdater.put(key, nextDoc.right);
                }
            }
        }
        return next != null;
    }
}