/*
 *
 * 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.qpid.server.protocol.v0_8;

import org.apache.qpid.server.filter.AMQPFilterTypes;
import org.apache.qpid.server.consumer.AbstractConsumerTarget;
import org.apache.qpid.server.flow.FlowCreditManager;
import org.apache.qpid.server.message.InstanceProperties;
import org.apache.qpid.server.message.MessageInstance;
import org.apache.qpid.server.message.MessageInstance.EntryState;
import org.apache.qpid.server.message.MessageInstanceConsumer;
import org.apache.qpid.server.message.MessageReference;
import org.apache.qpid.server.message.ServerMessage;
import org.apache.qpid.server.plugin.MessageConverter;
import org.apache.qpid.server.protocol.MessageConverterRegistry;
import org.apache.qpid.server.txn.AutoCommitTransaction;
import org.apache.qpid.server.txn.ServerTransaction;
import org.apache.qpid.server.util.StateChangeListener;

/**
 * Encapsulation of a subscription to a queue.
 * <p>
 * Ties together the protocol session of a subscriber, the consumer tag
 * that was given out by the broker and the channel id.
 */
public abstract class ConsumerTarget_0_8 extends AbstractConsumerTarget<ConsumerTarget_0_8>
{

    private final ClientDeliveryMethod _deliveryMethod;

    private final String _targetAddress;


    public static ConsumerTarget_0_8 createBrowserTarget(AMQChannel channel,
                                                         AMQShortString consumerTag, FieldTable filters,
                                                         FlowCreditManager_0_8 creditManager, final boolean multiQueue)
    {
        return new BrowserConsumer(channel, consumerTag, filters, creditManager, channel.getClientDeliveryMethod(),
                                   multiQueue);
    }

    public static ConsumerTarget_0_8 createGetNoAckTarget(final AMQChannel channel,
                                                          final AMQShortString consumerTag,
                                                          final FieldTable filters,
                                                          final FlowCreditManager_0_8 creditManager,
                                                          final ClientDeliveryMethod deliveryMethod)
    {
        return new GetNoAckConsumer(channel, consumerTag, filters, creditManager, deliveryMethod);
    }

    static final class BrowserConsumer extends ConsumerTarget_0_8
    {
        public BrowserConsumer(AMQChannel channel,
                               AMQShortString consumerTag,
                               FieldTable filters,
                               FlowCreditManager_0_8 creditManager,
                               ClientDeliveryMethod deliveryMethod,
                               boolean multiQueue)
        {
            super(channel, consumerTag,
                  filters, creditManager, deliveryMethod, multiQueue);
        }

        @Override
        protected void doSendInternal(final MessageInstanceConsumer consumer,
                                      final MessageInstance entry,
                                      final AMQMessage message,
                                      final boolean batch)
        {
            // We don't decrement the reference here as we don't want to consume the message
            // but we do want to send it to the client.

            long deliveryTag = getChannel().getNextDeliveryTag();
            sendToClient(consumer, message, entry.getInstanceProperties(), deliveryTag);
        }
    }

    public static ConsumerTarget_0_8 createNoAckTarget(AMQChannel channel,
                                                       AMQShortString consumerTag, FieldTable filters,
                                                       FlowCreditManager_0_8 creditManager,
                                                       boolean multiQueue)
    {
        return new NoAckConsumer(channel, consumerTag, filters, creditManager, channel.getClientDeliveryMethod(),
                                 multiQueue);
    }

    public static class NoAckConsumer extends ConsumerTarget_0_8
    {
        private final AutoCommitTransaction _txn;

        public NoAckConsumer(AMQChannel channel,
                             AMQShortString consumerTag,
                             FieldTable filters,
                             FlowCreditManager_0_8 creditManager,
                             ClientDeliveryMethod deliveryMethod,
                             boolean multiQueue)
        {
            super(channel, consumerTag, filters, creditManager, deliveryMethod, multiQueue);

            _txn = new AutoCommitTransaction(channel.getAddressSpace().getMessageStore());
        }

        @Override
        protected void doSendInternal(final MessageInstanceConsumer consumer,
                                      final MessageInstance entry,
                                      final AMQMessage message,
                                      final boolean batch)
        {
            // if we do not need to wait for client acknowledgements
            // we can decrement the reference count immediately.

            // By doing this _before_ the send we ensure that it
            // doesn't get sent if it can't be dequeued, preventing
            // duplicate delivery on recovery.

            // The send may of course still fail, in which case, as
            // the message is unacked, it will be lost.
            _txn.dequeue(entry.getEnqueueRecord(), NOOP);

            try( MessageReference ref = entry.getMessage().newReference())
            {
                InstanceProperties props = entry.getInstanceProperties();
                entry.delete();
                getChannel().getConnection().setDeferFlush(batch);
                long deliveryTag = getChannel().getNextDeliveryTag();

                sendToClient(consumer, message, props, deliveryTag);
            }
        }

        private static final ServerTransaction.Action NOOP =
                new ServerTransaction.Action()
                {
                    @Override
                    public void postCommit()
                    {
                    }

                    @Override
                    public void onRollback()
                    {
                    }
                };
    }

    /**
     * NoAck Subscription for use with BasicGet method.
     */
    public static final class GetNoAckConsumer extends NoAckConsumer
    {
        public GetNoAckConsumer(AMQChannel channel,
                                AMQShortString consumerTag, FieldTable filters,
                                FlowCreditManager_0_8 creditManager,
                                ClientDeliveryMethod deliveryMethod)
        {
            super(channel, consumerTag, filters, creditManager, deliveryMethod, false);
        }

    }


    public static ConsumerTarget_0_8 createAckTarget(AMQChannel channel,
                                                     AMQShortString consumerTag,
                                                     FieldTable filters,
                                                     FlowCreditManager_0_8 creditManager,
                                                     boolean multiQueue)
    {
        return new AckConsumer(channel,
                               consumerTag,
                               filters, creditManager,
                               channel.getClientDeliveryMethod(),
                               multiQueue, true);
    }


    public static ConsumerTarget_0_8 createGetAckTarget(AMQChannel channel,
                                                        AMQShortString consumerTag, FieldTable filters,
                                                        FlowCreditManager_0_8 creditManager,
                                                        ClientDeliveryMethod deliveryMethod)
    {
        return new AckConsumer(channel, consumerTag, filters, creditManager, deliveryMethod, false, false);
    }

    static final class AckConsumer extends ConsumerTarget_0_8
    {
        private final boolean _usesCredit;

        public AckConsumer(AMQChannel channel,
                           AMQShortString consumerTag, FieldTable filters,
                           FlowCreditManager_0_8 creditManager,
                           ClientDeliveryMethod deliveryMethod,
                           boolean multiQueue,
                           final boolean usesCredit)
        {
            super(channel, consumerTag, filters, creditManager, deliveryMethod, multiQueue);
            _usesCredit = usesCredit;
        }

        @Override
        protected void doSendInternal(final MessageInstanceConsumer consumer,
                                      final MessageInstance entry,
                                      final AMQMessage message,
                                      final boolean batch)
        {
            // put queue entry on a list and then notify the connection to read list.
            synchronized (getChannel())
            {
                getChannel().getConnection().setDeferFlush(batch);
                long deliveryTag = getChannel().getNextDeliveryTag();

                addUnacknowledgedMessage(entry);
                getChannel().addUnacknowledgedMessage(entry, deliveryTag, consumer, _usesCredit);
                sendToClient(consumer, message, entry.getInstanceProperties(), deliveryTag);
                entry.incrementDeliveryCount();
            }
        }
    }

    private final AMQChannel _channel;

    private final AMQShortString _consumerTag;

    private final FlowCreditManager_0_8 _creditManager;

    private final Boolean _autoClose;

    public ConsumerTarget_0_8(AMQChannel channel,
                              AMQShortString consumerTag,
                              FieldTable arguments,
                              FlowCreditManager_0_8 creditManager,
                              ClientDeliveryMethod deliveryMethod,
                              boolean multiQueue)
    {
        super(multiQueue, channel.getAMQPConnection());

        _channel = channel;
        _consumerTag = consumerTag;

        _creditManager = creditManager;

        _deliveryMethod = deliveryMethod;

        if (arguments != null)
        {
            Object autoClose = arguments.get(AMQPFilterTypes.AUTO_CLOSE.getValue());
            if (autoClose != null)
            {
                _autoClose = (Boolean) autoClose;
            }
            else
            {
                _autoClose = false;
            }
            if(arguments.containsKey("local-address"))
            {
                _targetAddress = String.valueOf(arguments.get("local-address"));
            }
            else
            {
                _targetAddress = consumerTag.toString();
            }
        }
        else
        {
            _autoClose = false;
            _targetAddress = consumerTag.toString();

        }
    }

    @Override
    public String getTargetAddress()
    {
        return _targetAddress;
    }

    @Override
    public AMQChannel getSession()
    {
        return _channel;
    }

    @Override
    public String toString()
    {

        return "ConsumerTarget_0_8[channel=" + _channel +
                            ", consumerTag=" + _consumerTag +
                            ", session=" + getConnection().getRemoteAddressString() + "]";
    }

    @Override
    public void updateNotifyWorkDesired()
    {
        final AMQPConnection_0_8 amqpConnection = (AMQPConnection_0_8) _channel.getAMQPConnection();

        boolean state = _channel.isChannelFlow()
                        && !amqpConnection.isTransportBlockedForWriting()
                        // this last condition does not need to exist for browsers and no ack
                        && getCreditManager().hasCredit();

        setNotifyWorkDesired(state);
    }

    public boolean isAutoClose()
    {
        return _autoClose;
    }

    public FlowCreditManager getCreditManager()
    {
        return _creditManager;
    }

    @Override
    public boolean allocateCredit(ServerMessage msg)
    {
        boolean hasCredit = _creditManager.hasCredit();
        boolean allocated = _creditManager.useCreditForMessage(msg.getSize());
        if(hasCredit != _creditManager.hasCredit())
        {
            _channel.updateAllConsumerNotifyWorkDesired();
        }
        return allocated;
    }

    public AMQChannel getChannel()
    {
        return _channel;
    }

    public AMQShortString getConsumerTag()
    {
        return _consumerTag;
    }

    private AMQPConnection_0_8 getConnection()
    {
        return _channel.getConnection();
    }

    @Override
    public void restoreCredit(final ServerMessage message)
    {
        // This method is only called when the queue is restoring credit it allocated and then could not use
        _creditManager.restoreCredit(1, message.getSize());
        updateNotifyWorkDesired();
    }

    protected long sendToClient(final MessageInstanceConsumer consumer, final AMQMessage message,
                                final InstanceProperties props,
                                final long deliveryTag)
    {
        return _deliveryMethod.deliverToClient(this, message, props, deliveryTag);

    }


    public void confirmAutoClose()
    {
        ProtocolOutputConverter converter = getChannel().getConnection().getProtocolOutputConverter();
        converter.confirmConsumerAutoClose(getChannel().getChannelId(), getConsumerTag());
    }

    @Override
    public void noMessagesAvailable()
    {
        if(isAutoClose() && getState() != State.CLOSED)
        {
            close();
            confirmAutoClose();
        }
    }

    @Override
    final protected void doSend(final MessageInstanceConsumer consumer, final MessageInstance entry, final boolean batch)
    {
        ServerMessage serverMessage = entry.getMessage();
        MessageConverter<ServerMessage<?>, AMQMessage> messageConverter = null;
        final AMQMessage msg;
        if(serverMessage instanceof AMQMessage)
        {
            msg = (AMQMessage) serverMessage;
        }
        else
        {
            messageConverter = MessageConverterRegistry.getConverter((Class<ServerMessage<?>>) serverMessage.getClass(), AMQMessage.class);
            msg = messageConverter.convert(serverMessage, getConnection().getAddressSpace());
        }

        try
        {
            doSendInternal(consumer, entry, msg, batch);
        }
        finally
        {
            if(messageConverter != null)
            {
                messageConverter.dispose(msg);
            }
        }
    }

    protected abstract void doSendInternal(final MessageInstanceConsumer consumer,
                                           final MessageInstance entry,
                                           final AMQMessage message,
                                           final boolean batch);


    @Override
    public void flushBatched()
    {
        _channel.getConnection().setDeferFlush(false);
    }

    protected void addUnacknowledgedMessage(MessageInstance entry)
    {
        _unacknowledgedBytes.addAndGet(entry.getMessage().getSizeIncludingHeader());
        _unacknowledgedCount.incrementAndGet();
        entry.addStateChangeListener(_unacknowledgedMessageListener);
    }

    private void removeUnacknowledgedMessage(MessageInstance entry)
    {
        _unacknowledgedBytes.addAndGet(-entry.getMessage().getSizeIncludingHeader());
        _unacknowledgedCount.decrementAndGet();
    }

    private final StateChangeListener<MessageInstance, EntryState> _unacknowledgedMessageListener = new StateChangeListener<MessageInstance, EntryState>()
    {
        @Override
        public void stateChanged(MessageInstance entry, EntryState oldState, EntryState newState)
        {
            if (isConsumerAcquiredStateForThis(oldState) && !isConsumerAcquiredStateForThis(newState))
            {
                removeUnacknowledgedMessage(entry);
                entry.removeStateChangeListener(this);
            }
        }

        private boolean isConsumerAcquiredStateForThis(EntryState state)
        {
            return state instanceof MessageInstance.ConsumerAcquiredState
                   && ((MessageInstance.ConsumerAcquiredState) state).getConsumer().getTarget() == ConsumerTarget_0_8.this;
        }
    };
}