/*
 * 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.
 */

#ifndef _ACTIVEMQ_CORE_KERNELS_ACTIVEMQSESSIONKERNEL_H_
#define _ACTIVEMQ_CORE_KERNELS_ACTIVEMQSESSIONKERNEL_H_

#include <cms/Session.h>
#include <cms/ExceptionListener.h>

#include <activemq/util/Config.h>
#include <activemq/util/Usage.h>
#include <activemq/exceptions/ActiveMQException.h>
#include <activemq/core/ActiveMQTransactionContext.h>
#include <activemq/core/kernels/ActiveMQConsumerKernel.h>
#include <activemq/core/kernels/ActiveMQProducerKernel.h>
#include <activemq/commands/ActiveMQTempDestination.h>
#include <activemq/commands/Response.h>
#include <activemq/commands/MessageAck.h>
#include <activemq/commands/SessionInfo.h>
#include <activemq/commands/ConsumerInfo.h>
#include <activemq/commands/ConsumerId.h>
#include <activemq/commands/ProducerId.h>
#include <activemq/commands/TransactionId.h>
#include <activemq/core/Dispatcher.h>
#include <activemq/core/MessageDispatchChannel.h>
#include <activemq/util/LongSequenceGenerator.h>
#include <activemq/threads/Scheduler.h>

#include <decaf/lang/Pointer.h>
#include <decaf/util/Properties.h>
#include <decaf/util/concurrent/atomic/AtomicBoolean.h>

#include <string>
#include <memory>

namespace activemq {
namespace core {

    class ActiveMQConnection;
    class ActiveMQConsumer;
    class ActiveMQProducer;
    class ActiveMQSessionExecutor;

namespace kernels {

    using decaf::lang::Pointer;
    using decaf::util::concurrent::atomic::AtomicBoolean;

    class SessionConfig;

    class AMQCPP_API ActiveMQSessionKernel : public virtual cms::Session, public Dispatcher {
    private:

        friend class activemq::core::ActiveMQSessionExecutor;

    protected:

        SessionConfig* config;

        /**
         * SessionInfo for this Session
         */
        Pointer<commands::SessionInfo> sessionInfo;

        /**
         * Transaction Management object
         */
        Pointer<ActiveMQTransactionContext> transaction;

        /**
         * Connection
         */
        ActiveMQConnection* connection;

        /**
         * Indicates that this connection has been closed, it is no longer
         * usable after this becomes true
         */
        AtomicBoolean closed;

        /**
         * Sends incoming messages to the registered consumers.
         */
        std::auto_ptr<ActiveMQSessionExecutor> executor;

        /**
         * This Sessions Acknowledgment mode.
         */
        cms::Session::AcknowledgeMode ackMode;

        /**
         * Next available Producer Id
         */
        util::LongSequenceGenerator producerIds;

        /**
         * Next available Producer Sequence Id
         */
        util::LongSequenceGenerator producerSequenceIds;

        /**
         * Next available Consumer Id
         */
        util::LongSequenceGenerator consumerIds;

        /**
         * Last Delivered Sequence Id
         */
        long long lastDeliveredSequenceId;

    private:

        ActiveMQSessionKernel(const ActiveMQSessionKernel&);
        ActiveMQSessionKernel& operator=(const ActiveMQSessionKernel&);

    public:

        ActiveMQSessionKernel(ActiveMQConnection* connection,
                              const Pointer<commands::SessionId>& id,
                              cms::Session::AcknowledgeMode ackMode,
                              const decaf::util::Properties& properties);

        virtual ~ActiveMQSessionKernel();

        /**
         * Redispatches the given set of unconsumed messages to the consumers.
         * @param unconsumedMessages - unconsumed messages to be redelivered.
         */
        virtual void redispatch(MessageDispatchChannel& unconsumedMessages);

        /**
         * Stops asynchronous message delivery.
         */
        virtual void start();

        /**
         * Starts asynchronous message delivery.
         */
        virtual void stop();

        /**
         * Indicates whether or not the session is currently in the started
         * state.
         */
        bool isStarted() const;

        virtual bool isAutoAcknowledge() const {
            return this->ackMode == cms::Session::AUTO_ACKNOWLEDGE;
        }

        virtual bool isDupsOkAcknowledge() const {
            return this->ackMode == cms::Session::DUPS_OK_ACKNOWLEDGE;
        }

        virtual bool isClientAcknowledge() const {
            return this->ackMode == cms::Session::CLIENT_ACKNOWLEDGE;
        }

        virtual bool isIndividualAcknowledge() const {
            return this->ackMode == cms::Session::INDIVIDUAL_ACKNOWLEDGE;
        }

        /**
         * Fires the given exception to the exception listener of the connection
         */
        void fire(const exceptions::ActiveMQException& ex);

    public:  // Methods from ActiveMQMessageDispatcher

        /**
         * Dispatches a message to a particular consumer.
         * @param message - the message to be dispatched
         */
        virtual void dispatch(const Pointer<MessageDispatch>& message);

    public:   // Implements Methods

        virtual void close();

        virtual void commit();

        virtual void rollback();

        virtual void recover();

        virtual cms::MessageConsumer* createConsumer(const cms::Destination* destination);

        virtual cms::MessageConsumer* createConsumer(const cms::Destination* destination,
                                                     const std::string& selector);

        virtual cms::MessageConsumer* createConsumer(const cms::Destination* destination,
                                                     const std::string& selector,
                                                     bool noLocal);

        virtual cms::MessageConsumer* createDurableConsumer(const cms::Topic* destination,
                                                            const std::string& name,
                                                            const std::string& selector,
                                                            bool noLocal = false);

        virtual cms::MessageProducer* createProducer(const cms::Destination* destination);

        virtual cms::QueueBrowser* createBrowser(const cms::Queue* queue);

        virtual cms::QueueBrowser* createBrowser(const cms::Queue* queue, const std::string& selector);

        virtual cms::Queue* createQueue(const std::string& queueName);

        virtual cms::Topic* createTopic(const std::string& topicName);

        virtual cms::TemporaryQueue* createTemporaryQueue();

        virtual cms::TemporaryTopic* createTemporaryTopic();

        virtual cms::Message* createMessage();

        virtual cms::BytesMessage* createBytesMessage();

        virtual cms::BytesMessage* createBytesMessage(const unsigned char* bytes, int bytesSize);

        virtual cms::StreamMessage* createStreamMessage();

        virtual cms::TextMessage* createTextMessage();

        virtual cms::TextMessage* createTextMessage( const std::string& text );

        virtual cms::MapMessage* createMapMessage();

        virtual cms::Session::AcknowledgeMode getAcknowledgeMode() const;

        virtual bool isTransacted() const;

        virtual void unsubscribe(const std::string& name);

   public:   // ActiveMQSessionKernel specific Methods

        /**
         * Sends a message from the Producer specified using this session's connection
         * the message will be sent using the best available means depending on the
         * configuration of the connection.
         * <p>
         * Asynchronous sends will be chosen if at all possible.
         *
         * @param producer
         *      The sending Producer
         * @param destination
         *      The target destination for the Message.
         * @param message
         *      The message to send to the broker.
         * @param deliveryMode
         *      The delivery mode to assign to the outgoing message.
         * @param priority
         *      The priority value to assign to the outgoing message.
         * @param timeToLive
         *      The time to live for the outgoing message.
         * @param usage
         *      Pointer to a Usage tracker which if set will be increased by the size
         *      of the given message.
         * @param sendTimeout
         *      The amount of time to block during send before failing, or 0 to wait forever.
         *
         * @throws CMSException if an error occurs while sending the message.
         */
        void send(kernels::ActiveMQProducerKernel* producer, Pointer<commands::ActiveMQDestination> destination,
                  cms::Message* message, int deliveryMode, int priority, long long timeToLive,
                  util::MemoryUsage* producerWindow, long long sendTimeout, cms::AsyncCallback* onComplete);

        /**
         * This method gets any registered exception listener of this sessions
         * connection and returns it.  Mainly intended for use by the objects
         * that this session creates so that they can notify the client of
         * exceptions that occur in the context of another thread.
         *
         * @returns the registered cms::ExceptionListener pointer or NULL
         */
        cms::ExceptionListener* getExceptionListener();

        /**
         * Set an MessageTransformer instance that is passed on to all MessageProducer and MessageConsumer
         * objects created from this Session.
         *
         * @param transformer
         *      Pointer to the cms::MessageTransformer to set on all MessageConsumers and MessageProducers.
         */
        virtual void setMessageTransformer(cms::MessageTransformer* transformer);

        /**
         * Gets the currently configured MessageTransformer for this Session.
         *
         * @returns the pointer to the currently set cms::MessageTransformer.
         */
        virtual cms::MessageTransformer* getMessageTransformer() const;

        /**
         * Gets the Session Information object for this session, if the
         * session is closed than this method throws an exception.
         * @return SessionInfo Reference
         */
        const commands::SessionInfo& getSessionInfo() const {
            this->checkClosed();
            return *( this->sessionInfo );
        }

        /**
         * Gets the Session Id object for this session, if the session
         * is closed than this method throws an exception.
         * @return SessionId Reference
         */
        const commands::SessionId& getSessionId() const {
            this->checkClosed();
            return *( this->sessionInfo->getSessionId() );
        }

        /**
         * Gets the ActiveMQConnection that is associated with this session.
         */
        ActiveMQConnection* getConnection() const {
            return this->connection;
        }

        /**
         * Gets a Pointer to this Session's Scheduler instance
         */
        Pointer<threads::Scheduler> getScheduler() const;

        /**
         * Gets the currently set Last Delivered Sequence Id
         *
         * @returns long long containing the sequence id of the last delivered Message.
         */
        long long getLastDeliveredSequenceId() const {
            return this->lastDeliveredSequenceId;
        }

        /**
         * Sets the value of the Last Delivered Sequence Id
         *
         * @param value
         *      The new value to assign to the Last Delivered Sequence Id property.
         */
        void setLastDeliveredSequenceId(long long value) {
            this->lastDeliveredSequenceId = value;
        }

        /**
         * Sends a Command to the broker without requesting any Response be returned.
         * .
         * @param command
         *      The message to send to the Broker.
         *
         * @throws ActiveMQException if not currently connected, or if the
         *         operation fails for any reason.
         */
        void oneway(Pointer<commands::Command> command);

        /**
         * Sends a synchronous request and returns the response from the broker.
         * Converts any error responses into an exception.
         *
         * @param command
         *      The command to send to the broker.
         * @param timeout
         *      The time to wait for a response, default is zero or infinite.
         *
         * @returns Pointer to a Response object that the broker has returned for the Command sent.
         *
         * @throws ActiveMQException thrown if an error response was received
         *         from the broker, or if any other error occurred.
         */
        Pointer<commands::Response> syncRequest(Pointer<commands::Command> command, unsigned int timeout = 0);

        /**
         * Adds a MessageConsumerKernel to this session registering it with the Connection and
         * store a reference to it so the session can ensure that all resources are closed when
         * the session is closed.
         *
         * @param consumer
         *      The ActiveMQConsumerKernel instance to add to this session.
         *
         * @throw ActiveMQException if an internal error occurs.
         */
        void addConsumer(Pointer<ActiveMQConsumerKernel> consumer);

        /**
         * Dispose of a MessageConsumer from this session.  Removes it from the Connection
         * and clean up any resources associated with it.
         *
         * @param consumer
         *      The ActiveMQConsumerKernel instance to remove from this session.
         *
         * @throw ActiveMQException if an internal error occurs.
         */
        void removeConsumer(Pointer<ActiveMQConsumerKernel> consumer);

        /**
         * Adds a MessageProducer to this session registering it with the Connection and store
         * a reference to it so the session can ensure that all resources are closed when
         * the session is closed.
         *
         * @param producer
         *      The ActiveMQProducerKernel instance to add to this session.
         *
         * @throw ActiveMQException if an internal error occurs.
         */
        void addProducer(Pointer<ActiveMQProducerKernel> producer);

        /**
         * Dispose of a MessageProducer from this session.  Removes it from the Connection
         * and clean up any resources associated with it.
         *
         * @param producer
         *      The Producer kernel instance to remove from this session.
         *
         * @throw ActiveMQException if an internal error occurs.
         */
        void removeProducer(Pointer<ActiveMQProducerKernel> producer);

        /**
         * Starts if not already start a Transaction for this Session.  If the session
         * is not a Transacted Session then an exception is thrown.  If a transaction is
         * already in progress then this method has no effect.
         *
         * @throw ActiveMQException if this is not a Transacted Session.
         */
        virtual void doStartTransaction();

        /**
         * Gets the Pointer to this Session's TransactionContext
         *
         * @return a Pointer to this Session's TransactionContext
         */
        Pointer<ActiveMQTransactionContext> getTransactionContext() {
            return this->transaction;
        }

        /**
         * Request that the Session inform all its consumers to Acknowledge all Message's
         * that have been received so far.
         */
        void acknowledge();

        /**
         * Request that this Session inform all of its consumers to deliver their pending
         * acks.
         */
        void deliverAcks();

        /**
         * Request that this Session inform all of its consumers to clear all messages that
         * are currently in progress.
         */
        void clearMessagesInProgress();

        /**
         * Causes the Session to wakeup its executer and ensure all messages are dispatched.
         */
        void wakeup();

        /**
         * Get the Next available Consumer Id
         * @return the next id in the sequence.
         */
        Pointer<commands::ConsumerId> getNextConsumerId();

        /**
         * Get the Next available Producer Id
         * @return the next id in the sequence.
         */
        Pointer<commands::ProducerId> getNextProducerId();

        /**
         * Performs the actual Session close operations.  This method is meant for use
         * by ActiveMQConnection, the connection object calls this when it has been
         * closed to skip some of the extraneous processing done by the client level
         * close method.
         */
        void doClose();

        /**
         * Cleans up the Session object's resources without attempting to send the
         * Remove command to the broker, this can be called from ActiveMQConnection when
         * it knows that the transport is down and the doClose method would throw an
         * exception when it attempt to send the Remove Command.
         */
        void dispose();

        /**
         * Set the prefetch level for the given consumer if it exists in this Session to
         * the value specified.
         *
         * @param id
         *      The consumer Id to search for and set prefetch level.
         * @param prefetch
         *      The new prefetch value.
         */
        void setPrefetchSize(Pointer<commands::ConsumerId> id, int prefetch);

        /**
         * Close the specified consumer if present in this Session.
         *
         * @param id
         *      The consumer Id to close.
         */
        void close(Pointer<commands::ConsumerId> id);

        /**
         * Checks if the given destination is currently in use by any consumers in this Session.
         *
         * @return true if there is a consumer of this destination in this Session.
         */
        bool isInUse(Pointer<commands::ActiveMQDestination> destination);

        /**
         * @returns a Pointer to an ActiveMQProducerKernel using its ProducerId, or NULL.
         */
        Pointer<ActiveMQProducerKernel> lookupProducerKernel(Pointer<commands::ProducerId> id);

        /**
         * @returns a Pointer to an ActiveMQProducerKernel using its ProducerId, or NULL.
         */
        Pointer<ActiveMQConsumerKernel> lookupConsumerKernel(Pointer<commands::ConsumerId> id);

        /**
         * Gives each consumer a chance to dispatch messages that have been enqueued by calling
         * each consumers iterate method.  Returns true if this method needs to be called again
         * because a consumer requires further processing time to complete its dispatching.  Once
         * all consumers are done this method returns false.
         *
         * @returns true if more iterations are needed false otherwise.
         */
        bool iterateConsumers();

        /**
         * Checks if any MessageConsumer owned by this Session has a set MessageListener
         * and throws an exception if so.  This enforces the rule that the MessageConsumers
         * belonging to a Session either operate in sync or async receive as a group.
         */
        void checkMessageListener() const;

        /**
         * Returns a Hash Code for this Session based on its SessionId.
         *
         * @returns an int hash code based on the string balue of SessionId.
         */
        virtual int getHashCode() const;

        /**
         * Sends the given MessageAck command to the Broker either via Synchronous call or
         * an Asynchronous call depending on the value of the async parameter.
         *
         * @param ack
         *      The MessageAck command to send.
         * @param async
         *      True if the command can be sent asynchronously.
         */
        void sendAck(decaf::lang::Pointer<commands::MessageAck> ack, bool async = false);

   private:

       /**
        * Get the Next available Producer Sequence Id
        * @return the next id in the sequence.
        */
       long long getNextProducerSequenceId() {
           return this->producerSequenceIds.getNextSequenceId();
       }

       // Checks for the closed state and throws if so.
       void checkClosed() const;

       // Send the Destination Creation Request to the Broker, alerting it
       // that we've created a new Temporary Destination.
       // @param tempDestination - The new Temporary Destination
       void createTemporaryDestination(commands::ActiveMQTempDestination* tempDestination);

       // Send the Destination Destruction Request to the Broker, alerting
       // it that we've removed an existing Temporary Destination.
       // @param tempDestination - The Temporary Destination to remove
       void destroyTemporaryDestination(commands::ActiveMQTempDestination* tempDestination);

       // Creates a new Temporary Destination name using the connection id
       // and a rolling count.
       // @returns a unique Temporary Destination name
       std::string createTemporaryDestinationName();

    };

}}}

#endif /* _ACTIVEMQ_CORE_KERNELS_ACTIVEMQSESSIONKERNEL_H_ */