/**
 * 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.activemq.broker.region.cursors;

import java.io.IOException;

import org.apache.activemq.broker.Broker;
import org.apache.activemq.broker.BrokerService;
import org.apache.activemq.broker.region.Queue;
import org.apache.activemq.command.Message;
import org.apache.activemq.command.MessageId;
import org.apache.activemq.store.MessageStore;
import org.apache.activemq.store.memory.MemoryMessageStore;
import org.apache.activemq.store.memory.MemoryTransactionStore;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * persist pending messages pending message (messages awaiting dispatch to a
 * consumer) cursor
 *
 *
 */
class QueueStorePrefetch extends AbstractStoreCursor {
    private static final Logger LOG = LoggerFactory.getLogger(QueueStorePrefetch.class);
    private final MessageStore store;
    private final Queue queue;
    private final Broker broker;

    /**
     * Construct it
     * @param queue
     */
    public QueueStorePrefetch(Queue queue, Broker broker) {
        super(queue);
        this.queue = queue;
        this.store = queue.getMessageStore();
        this.broker = broker;

    }

    @Override
    public boolean recoverMessageReference(MessageId messageReference) throws Exception {
        Message msg = this.store.getMessage(messageReference);
        if (msg != null) {
            return recoverMessage(msg);
        } else {
            String err = "Failed to retrieve message for id: " + messageReference;
            LOG.error(err);
            throw new IOException(err);
        }
    }



    @Override
    protected synchronized int getStoreSize() {
        try {
            int result = this.store.getMessageCount();
            return result;

        } catch (IOException e) {
            LOG.error("Failed to get message count", e);
            throw new RuntimeException(e);
        }
    }

    @Override
    protected synchronized long getStoreMessageSize() {
        try {
            return this.store.getMessageSize();
        } catch (IOException e) {
            LOG.error("Failed to get message size", e);
            throw new RuntimeException(e);
        }
    }

    @Override
    protected boolean canEnableCash() {
        return super.canEnableCash() && queue.singlePendingSend();
    }

    @Override
    protected synchronized boolean isStoreEmpty() {
        try {
            return this.store.isEmpty();

        } catch (Exception e) {
            LOG.error("Failed to get message count", e);
            throw new RuntimeException(e);
        }
    }

    @Override
    protected void resetBatch() {
        this.store.resetBatching();
    }

    @Override
    protected void setBatch(MessageId messageId) throws Exception {
        if (LOG.isTraceEnabled()) {
            LOG.trace("{}  setBatch {} seq: {}, loc: {}", this, messageId, messageId.getFutureOrSequenceLong(), messageId.getEntryLocator());
        }
        store.setBatch(messageId);
        batchResetNeeded = false;
    }


    @Override
    protected void doFillBatch() throws Exception {
        hadSpace = this.hasSpace();
        if (!broker.getBrokerService().isPersistent() || hadSpace) {
            this.store.recoverNextMessages(this.maxBatchSize, this);
            dealWithDuplicates(); // without the index lock
        }
    }

    @Override
    public String toString(){
        return super.toString() + ",store=" + store;
    }
}