/**
 * 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.transport.stomp;

import java.io.IOException;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.LinkedList;
import java.util.Map;
import java.util.Map.Entry;

import javax.jms.JMSException;

import org.apache.activemq.command.ActiveMQBytesMessage;
import org.apache.activemq.command.ActiveMQDestination;
import org.apache.activemq.command.ActiveMQMessage;
import org.apache.activemq.command.ConsumerInfo;
import org.apache.activemq.command.MessageAck;
import org.apache.activemq.command.MessageDispatch;
import org.apache.activemq.command.MessageId;
import org.apache.activemq.command.TransactionId;

/**
 * Keeps track of the STOMP subscription so that acking is correctly done.
 *
 * @author <a href="http://hiramchirino.com">chirino</a>
 */
public class StompSubscription {

    public static final String AUTO_ACK = Stomp.Headers.Subscribe.AckModeValues.AUTO;
    public static final String CLIENT_ACK = Stomp.Headers.Subscribe.AckModeValues.CLIENT;
    public static final String INDIVIDUAL_ACK = Stomp.Headers.Subscribe.AckModeValues.INDIVIDUAL;

    protected final ProtocolConverter protocolConverter;
    protected final String subscriptionId;
    protected final ConsumerInfo consumerInfo;

    protected final LinkedHashMap<MessageId, MessageDispatch> dispatchedMessage = new LinkedHashMap<MessageId, MessageDispatch>();
    protected final LinkedList<MessageDispatch> unconsumedMessage = new LinkedList<MessageDispatch>();

    protected String ackMode = AUTO_ACK;
    protected ActiveMQDestination destination;
    protected String transformation;

    public StompSubscription(ProtocolConverter stompTransport, String subscriptionId, ConsumerInfo consumerInfo, String transformation) {
        this.protocolConverter = stompTransport;
        this.subscriptionId = subscriptionId;
        this.consumerInfo = consumerInfo;
        this.transformation = transformation;
    }

    void onMessageDispatch(MessageDispatch md, String ackId) throws IOException, JMSException {
        ActiveMQMessage message = (ActiveMQMessage)md.getMessage();
        if (ackMode == CLIENT_ACK) {
            synchronized (this) {
                dispatchedMessage.put(message.getMessageId(), md);
            }
        } else if (ackMode == INDIVIDUAL_ACK) {
            synchronized (this) {
                dispatchedMessage.put(message.getMessageId(), md);
            }
        } else if (ackMode == AUTO_ACK) {
            MessageAck ack = new MessageAck(md, MessageAck.STANDARD_ACK_TYPE, 1);
            protocolConverter.getStompTransport().sendToActiveMQ(ack);
        }

        boolean ignoreTransformation = false;

        if (transformation != null && !( message instanceof ActiveMQBytesMessage ) ) {
            message.setReadOnlyProperties(false);
            message.setStringProperty(Stomp.Headers.TRANSFORMATION, transformation);
        } else {
            if (message.getStringProperty(Stomp.Headers.TRANSFORMATION) != null) {
                ignoreTransformation = true;
            }
        }

        StompFrame command = protocolConverter.convertMessage(message, ignoreTransformation);

        command.setAction(Stomp.Responses.MESSAGE);
        if (subscriptionId != null) {
            command.getHeaders().put(Stomp.Headers.Message.SUBSCRIPTION, subscriptionId);
        }

        if (ackId != null) {
            command.getHeaders().put(Stomp.Headers.Message.ACK_ID, ackId);
        }

        protocolConverter.getStompTransport().sendToStomp(command);
    }

    synchronized void onStompAbort(TransactionId transactionId) {
        unconsumedMessage.clear();
    }

    void onStompCommit(TransactionId transactionId) {
        MessageAck ack = null;
        synchronized (this) {
            for (Iterator<?> iter = dispatchedMessage.entrySet().iterator(); iter.hasNext();) {
                @SuppressWarnings("rawtypes")
                Map.Entry entry = (Entry)iter.next();
                MessageDispatch msg = (MessageDispatch)entry.getValue();
                if (unconsumedMessage.contains(msg)) {
                    iter.remove();
                }
            }

            if (!unconsumedMessage.isEmpty()) {
                ack = new MessageAck(unconsumedMessage.getLast(), MessageAck.STANDARD_ACK_TYPE, unconsumedMessage.size());
                unconsumedMessage.clear();
            }
        }
        // avoid contention with onMessageDispatch
        if (ack != null) {
            protocolConverter.getStompTransport().sendToActiveMQ(ack);
        }
    }

    synchronized MessageAck onStompMessageAck(String messageId, TransactionId transactionId) {

        MessageId msgId = new MessageId(messageId);

        if (!dispatchedMessage.containsKey(msgId)) {
            return null;
        }

        MessageAck ack = new MessageAck();
        ack.setDestination(consumerInfo.getDestination());
        ack.setConsumerId(consumerInfo.getConsumerId());

        if (ackMode == CLIENT_ACK) {
            if (transactionId == null) {
                ack.setAckType(MessageAck.STANDARD_ACK_TYPE);
            } else {
                ack.setAckType(MessageAck.DELIVERED_ACK_TYPE);
            }
            int count = 0;
            for (Iterator<?> iter = dispatchedMessage.entrySet().iterator(); iter.hasNext();) {

                @SuppressWarnings("rawtypes")
                Map.Entry entry = (Entry)iter.next();
                MessageId id = (MessageId)entry.getKey();
                MessageDispatch msg = (MessageDispatch)entry.getValue();

                if (transactionId != null) {
                    if (!unconsumedMessage.contains(msg)) {
                        unconsumedMessage.add(msg);
                        count++;
                    }
                } else {
                    iter.remove();
                    count++;
                }

                if (id.equals(msgId)) {
                    ack.setLastMessageId(id);
                    break;
                }
            }
            ack.setMessageCount(count);
            if (transactionId != null) {
                ack.setTransactionId(transactionId);
            }

        } else if (ackMode == INDIVIDUAL_ACK) {
            ack.setAckType(MessageAck.INDIVIDUAL_ACK_TYPE);
            ack.setMessageID(msgId);
            if (transactionId != null) {
                unconsumedMessage.add(dispatchedMessage.get(msgId));
                ack.setTransactionId(transactionId);
            }
            dispatchedMessage.remove(msgId);
        }
        return ack;
    }

    public MessageAck onStompMessageNack(String messageId, TransactionId transactionId) throws ProtocolException {

        MessageId msgId = new MessageId(messageId);

        if (!dispatchedMessage.containsKey(msgId)) {
            return null;
        }

        MessageAck ack = new MessageAck();
        ack.setDestination(consumerInfo.getDestination());
        ack.setConsumerId(consumerInfo.getConsumerId());
        ack.setAckType(MessageAck.POSION_ACK_TYPE);
        ack.setMessageID(msgId);
        if (transactionId != null) {
            unconsumedMessage.add(dispatchedMessage.get(msgId));
            ack.setTransactionId(transactionId);
        }
        dispatchedMessage.remove(msgId);

        return ack;
    }

    public String getAckMode() {
        return ackMode;
    }

    public void setAckMode(String ackMode) {
        this.ackMode = ackMode;
    }

    public String getSubscriptionId() {
        return subscriptionId;
    }

    public void setDestination(ActiveMQDestination destination) {
        this.destination = destination;
    }

    public ActiveMQDestination getDestination() {
        return destination;
    }

    public ConsumerInfo getConsumerInfo() {
        return consumerInfo;
    }
}
