/********************************************************************************
 *    Copyright (C) 2014 GSI Helmholtzzentrum fuer Schwerionenforschung GmbH    *
 *                                                                              *
 *              This software is distributed under the terms of the             *
 *         GNU Lesser General Public Licence version 3 (LGPL) version 3,        *
 *                  copied verbatim in the file "LICENSE"                       *
 ********************************************************************************/
/**
 * FairMQChannel.h
 *
 * @since 2015-06-02
 * @author A. Rybalchenko
 */

#ifndef FAIRMQCHANNEL_H_
#define FAIRMQCHANNEL_H_

#include <string>
#include <memory> // unique_ptr
#include <vector>
#include <atomic>
#include <mutex>

#include "FairMQTransportFactory.h"
#include "FairMQSocket.h"
#include "FairMQPoller.h"
#include "FairMQTransports.h"
#include "FairMQLogger.h"

class FairMQPoller;
class FairMQTransportFactory;

class FairMQChannel
{
    friend class FairMQDevice;

  public:
    /// Default constructor
    FairMQChannel();

    /// Constructor
    /// @param type Socket type (push/pull/pub/sub/spub/xsub/pair/req/rep/dealer/router/)
    /// @param method Socket method (bind/connect)
    /// @param address Network address to bind/connect to (e.g. "tcp://127.0.0.1:5555" or "ipc://abc")
    FairMQChannel(const std::string& type, const std::string& method, const std::string& address);

    /// Copy Constructor
    FairMQChannel(const FairMQChannel&);

    /// Assignment operator
    FairMQChannel& operator=(const FairMQChannel&);

    /// Default destructor
    virtual ~FairMQChannel();

    FairMQSocket const & GetSocket() const;

    /// Get channel name
    /// @return Returns full channel name (e.g. "data[0]")
    std::string GetChannelName() const;

    /// Get channel prefix
    /// @return Returns channel prefix (e.g. "data")
    std::string GetChannelPrefix() const;

    /// Get socket type
    /// @return Returns socket type (push/pull/pub/sub/spub/xsub/pair/req/rep/dealer/router/)
    std::string GetType() const;

    /// Get socket method
    /// @return Returns socket method (bind/connect)
    std::string GetMethod() const;

    /// Get socket address (e.g. "tcp://127.0.0.1:5555" or "ipc://abc")
    /// @return Returns socket address (e.g. "tcp://127.0.0.1:5555" or "ipc://abc")
    std::string GetAddress() const;

    /// Get channel transport ("default", "zeromq", "nanomsg" or "shmem")
    /// @return Returns channel transport (e.g. "default", "zeromq", "nanomsg" or "shmem")
    std::string GetTransport() const;

    /// Get socket send buffer size (in number of messages)
    /// @return Returns socket send buffer size (in number of messages)
    int GetSndBufSize() const;

    /// Get socket receive buffer size (in number of messages)
    /// @return Returns socket receive buffer size (in number of messages)
    int GetRcvBufSize() const;

    /// Get socket kernel transmit send buffer size (in bytes)
    /// @return Returns socket kernel transmit send buffer size (in bytes)
    int GetSndKernelSize() const;

    /// Get socket kernel transmit receive buffer size (in bytes)
    /// @return Returns socket kernel transmit receive buffer size (in bytes)
    int GetRcvKernelSize() const;

    /// Get socket rate logging interval (in seconds)
    /// @return Returns socket rate logging interval (in seconds)
    int GetRateLogging() const;

    /// Set socket type
    /// @param type Socket type (push/pull/pub/sub/spub/xsub/pair/req/rep/dealer/router/)
    void UpdateType(const std::string& type);

    /// Set socket method
    /// @param method Socket method (bind/connect)
    void UpdateMethod(const std::string& method);

    /// Set socket address
    /// @param Socket address (e.g. "tcp://127.0.0.1:5555" or "ipc://abc")
    void UpdateAddress(const std::string& address);

    /// Set channel transport
    /// @param transport transport string ("default", "zeromq", "nanomsg" or "shmem")
    void UpdateTransport(const std::string& transport);

    /// Set socket send buffer size
    /// @param sndBufSize Socket send buffer size (in number of messages)
    void UpdateSndBufSize(const int sndBufSize);

    /// Set socket receive buffer size
    /// @param rcvBufSize Socket receive buffer size (in number of messages)
    void UpdateRcvBufSize(const int rcvBufSize);

    /// Set socket kernel transmit send buffer size (in bytes)
    /// @param sndKernelSize Socket send buffer size (in bytes)
    void UpdateSndKernelSize(const int sndKernelSize);

    /// Set socket kernel transmit receive buffer size (in bytes)
    /// @param rcvKernelSize Socket receive buffer size (in bytes)
    void UpdateRcvKernelSize(const int rcvKernelSize);

    /// Set socket rate logging interval (in seconds)
    /// @param rateLogging Socket rate logging interval (in seconds)
    void UpdateRateLogging(const int rateLogging);

    /// Checks if the configured channel settings are valid (checks the validity parameter, without running full validation (as oposed to ValidateChannel()))
    /// @return true if channel settings are valid, false otherwise.
    bool IsValid() const;

    /// Validates channel configuration
    /// @return true if channel settings are valid, false otherwise.
    bool ValidateChannel();

    /// Resets the channel (requires validation to be used again).
    void ResetChannel();

    int Send(std::unique_ptr<FairMQMessage>& msg) const;
    int Receive(std::unique_ptr<FairMQMessage>& msg) const;

    /// Sends a message to the socket queue.
    /// @details Send method attempts to send a message by
    /// putting it in the output queue. If the queue is full or queueing is not possible
    /// for some other reason (e.g. no peers connected for a binding socket), the method blocks.
    ///
    /// @param msg Constant reference of unique_ptr to a FairMQMessage
    /// @return Number of bytes that have been queued. -2 If queueing was not possible or timed out.
    /// In case of errors, returns -1.
    int Send(std::unique_ptr<FairMQMessage>& msg, int sndTimeoutInMs) const;

    /// Receives a message from the socket queue.
    /// @details Receive method attempts to receive a message from the input queue.
    /// If the queue is empty the method blocks.
    ///
    /// @param msg Constant reference of unique_ptr to a FairMQMessage
    /// @return Number of bytes that have been received. -2 If reading from the queue was not possible or timed out.
    /// In case of errors, returns -1.
    int Receive(std::unique_ptr<FairMQMessage>& msg, int rcvTimeoutInMs) const;

    /// Sends a message in non-blocking mode.
    /// @details SendAsync method attempts to send a message without blocking by
    /// putting it in the queue.
    ///
    /// @param msg Constant reference of unique_ptr to a FairMQMessage
    /// @return Number of bytes that have been queued. If queueing failed due to
    /// full queue or no connected peers (when binding), returns -2.
    /// In case of errors, returns -1.
    int SendAsync(std::unique_ptr<FairMQMessage>& msg) const;

    /// Receives a message in non-blocking mode.
    ///
    /// @param msg Constant reference of unique_ptr to a FairMQMessage
    /// @return Number of bytes that have been received. If queue is empty, returns -2.
    /// In case of errors, returns -1.
    int ReceiveAsync(std::unique_ptr<FairMQMessage>& msg) const;

    int64_t Send(std::vector<std::unique_ptr<FairMQMessage>>& msgVec) const;
    int64_t Receive(std::vector<std::unique_ptr<FairMQMessage>>& msgVec) const;

    /// Send a vector of messages
    ///
    /// @param msgVec message vector reference
    /// @return Number of bytes that have been queued. -2 If queueing was not possible or timed out.
    /// In case of errors, returns -1.
    int64_t Send(std::vector<std::unique_ptr<FairMQMessage>>& msgVec, int sndTimeoutInMs) const;

    /// Receive a vector of messages
    ///
    /// @param msgVec message vector reference
    /// @return Number of bytes that have been received. -2 If reading from the queue was not possible or timed out.
    /// In case of errors, returns -1.
    int64_t Receive(std::vector<std::unique_ptr<FairMQMessage>>& msgVec, int rcvTimeoutInMs) const;

    /// Sends a vector of message in non-blocking mode.
    /// @details SendAsync method attempts to send a vector of messages without blocking by
    /// putting it them the queue.
    ///
    /// @param msgVec message vector reference
    /// @return Number of bytes that have been queued. If queueing failed due to
    /// full queue or no connected peers (when binding), returns -2. In case of errors, returns -1.
    int64_t SendAsync(std::vector<std::unique_ptr<FairMQMessage>>& msgVec) const;

    /// Receives a vector of messages in non-blocking mode.
    ///
    /// @param msgVec message vector reference
    /// @return Number of bytes that have been received. If queue is empty, returns -2.
    /// In case of errors, returns -1.
    int64_t ReceiveAsync(std::vector<std::unique_ptr<FairMQMessage>>& msgVec) const;

    // TODO: this might go to some base utility library
    static void Tokenize(std::vector<std::string>& output, const std::string& input, const std::string delimiters = ",");

    unsigned long GetBytesTx() const;
    unsigned long GetBytesRx() const;
    unsigned long GetMessagesTx() const;
    unsigned long GetMessagesRx() const;

    FairMQTransportFactory* Transport();

  private:
    std::unique_ptr<FairMQSocket> fSocket;

    std::string fType;
    std::string fMethod;
    std::string fAddress;
    std::string fTransport;
    int fSndBufSize;
    int fRcvBufSize;
    int fSndKernelSize;
    int fRcvKernelSize;
    int fRateLogging;

    std::string fName;
    std::atomic<bool> fIsValid;


    FairMQPollerPtr fPoller;
    FairMQSocketPtr fChannelCmdSocket;

    FairMQ::Transport fTransportType;
    std::shared_ptr<FairMQTransportFactory> fTransportFactory;

    int fNoBlockFlag;
    int fSndMoreFlag;

    bool CheckCompatibility(std::unique_ptr<FairMQMessage>& msg) const;
    bool CheckCompatibility(std::vector<std::unique_ptr<FairMQMessage>>& msgVec) const;

    void InitTransport(std::shared_ptr<FairMQTransportFactory> factory);
    bool InitCommandInterface();

    bool HandleUnblock() const;

    // use static mutex to make the class easily copyable
    // implication: same mutex is used for all instances of the class
    // this does not hurt much, because mutex is used only during initialization with very low contention
    // possible TODO: improve this
    static std::mutex fChannelMutex;

    static std::atomic<bool> fInterrupted;
    bool fMultipart;
};

#endif /* FAIRMQCHANNEL_H_ */