/*
 * Licensed to Elasticsearch under one or more contributor
 * license agreements. See the NOTICE file distributed with
 * this work for additional information regarding copyright
 * ownership. Elasticsearch 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.elasticsearch.search;

import org.elasticsearch.common.io.stream.StreamInput;
import org.elasticsearch.common.io.stream.StreamOutput;
import org.elasticsearch.common.io.stream.Streamable;
import org.elasticsearch.common.unit.TimeValue;

import java.io.IOException;

import static org.elasticsearch.common.unit.TimeValue.readTimeValue;

/**
 * A scroll enables scrolling of search request. It holds a {@link #keepAlive()} time that
 * will control how long to keep the scrolling resources open.
 *
 *
 */
public class Scroll implements Streamable {

    private TimeValue keepAlive;

    private Scroll() {

    }

    /**
     * Constructs a new scroll of the provided keep alive.
     */
    public Scroll(TimeValue keepAlive) {
        this.keepAlive = keepAlive;
    }

    /**
     * How long the resources will be kept open to support the scroll request.
     */
    public TimeValue keepAlive() {
        return keepAlive;
    }

    public static Scroll readScroll(StreamInput in) throws IOException {
        Scroll scroll = new Scroll();
        scroll.readFrom(in);
        return scroll;
    }

    @Override
    public void readFrom(StreamInput in) throws IOException {
        if (in.readBoolean()) {
            keepAlive = readTimeValue(in);
        }
    }

    @Override
    public void writeTo(StreamOutput out) throws IOException {
        if (keepAlive == null) {
            out.writeBoolean(false);
        } else {
            out.writeBoolean(true);
            keepAlive.writeTo(out);
        }
    }
}