/*
 * 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.pulsar.broker.service.nonpersistent;

import java.util.List;
import lombok.Getter;
import lombok.extern.slf4j.Slf4j;
import org.apache.bookkeeper.mledger.Entry;
import org.apache.pulsar.broker.service.AbstractDispatcherSingleActiveConsumer;
import org.apache.pulsar.broker.service.Consumer;
import org.apache.pulsar.broker.service.EntryBatchSizes;
import org.apache.pulsar.broker.service.RedeliveryTracker;
import org.apache.pulsar.broker.service.RedeliveryTrackerDisabled;
import org.apache.pulsar.broker.service.SendMessageInfo;
import org.apache.pulsar.broker.service.Subscription;
import org.apache.pulsar.common.api.proto.CommandSubscribe.SubType;
import org.apache.pulsar.common.protocol.Commands;
import org.apache.pulsar.common.stats.Rate;

@Slf4j
public final class NonPersistentDispatcherSingleActiveConsumer extends AbstractDispatcherSingleActiveConsumer
        implements NonPersistentDispatcher {

    private final NonPersistentTopic topic;
    private final Rate msgDrop;
    @Getter
    protected final String name;
    private final Subscription subscription;
    private final RedeliveryTracker redeliveryTracker;

    public NonPersistentDispatcherSingleActiveConsumer(SubType subscriptionType, int partitionIndex,
                                                       NonPersistentTopic topic, Subscription subscription) {
        super(subscriptionType, partitionIndex, topic.getName(), subscription,
                topic.getBrokerService().pulsar().getConfiguration(), null);
        this.topic = topic;
        this.subscription = subscription;
        this.name = topic.getName() + " / " + subscription.getName();
        this.msgDrop = new Rate();
        this.redeliveryTracker = RedeliveryTrackerDisabled.REDELIVERY_TRACKER_DISABLED;
    }

    @Override
    public synchronized void sendMessages(List<Entry> entries) {
        Consumer currentConsumer = getActiveConsumer();
        if (currentConsumer != null && currentConsumer.getAvailablePermits() > 0 && currentConsumer.isWritable()) {
            SendMessageInfo sendMessageInfo = SendMessageInfo.getThreadLocal();
            EntryBatchSizes batchSizes = EntryBatchSizes.get(entries.size());
            filterEntriesForConsumer(entries, batchSizes, sendMessageInfo, null, null, false, currentConsumer);
            currentConsumer.sendMessages(entries, batchSizes, null, sendMessageInfo.getTotalMessages(),
                    sendMessageInfo.getTotalBytes(), sendMessageInfo.getTotalChunkedMessages(), getRedeliveryTracker());
        } else {
            entries.forEach(entry -> {
                int totalMsgs = Commands.getNumberOfMessagesInBatch(entry.getDataBuffer(), subscription.toString(), -1);
                if (totalMsgs > 0) {
                    msgDrop.recordEvent(totalMsgs);
                }
                entry.release();
            });
        }
    }

    @Override
    protected boolean isConsumersExceededOnSubscription() {
        return isConsumersExceededOnSubscription(topic, consumers.size());
    }

    @Override
    public Rate getMessageDropRate() {
        return msgDrop;
    }

    @Override
    public boolean hasPermits() {
        return getActiveConsumer() != null && getActiveConsumer().getAvailablePermits() > 0;
    }

    @Override
    public void consumerFlow(Consumer consumer, int additionalNumberOfMessages) {
        // No-op
    }

    @Override
    public RedeliveryTracker getRedeliveryTracker() {
        return redeliveryTracker;
    }

    @Override
    protected void scheduleReadOnActiveConsumer() {
        // No-op
    }

    @Override
    protected void cancelPendingRead() {
        // No-op
    }

    @Override
    protected void reScheduleRead() {
        // No-op
    }
}
