/*=========================================================================

  Program:   Visualization Toolkit
  Module:    vtkSocketCommunicator.h

  Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
  All rights reserved.
  See Copyright.txt or http://www.kitware.com/Copyright.htm for details.

     This software is distributed WITHOUT ANY WARRANTY; without even
     the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
     PURPOSE.  See the above copyright notice for more information.

=========================================================================*/
/**
 * @class   vtkSocketCommunicator
 * @brief   Process communication using Sockets
 *
 * This is a concrete implementation of vtkCommunicator which supports
 * interprocess communication using BSD style sockets.
 * It supports byte swapping for the communication of  machines
 * with different endianness.
 *
 * @warning
 * Communication between 32 bit and 64 bit systems is not fully
 * supported. If a type does not have the same length on both
 * systems, this communicator can not be used to transfer data
 * of that type.
 *
 * @sa
 * vtkCommunicator vtkSocketController
*/

#ifndef vtkSocketCommunicator_h
#define vtkSocketCommunicator_h

#include "vtkParallelCoreModule.h" // For export macro
#include "vtkCommunicator.h"

#include "vtkByteSwap.h" // Needed for vtkSwap macros

#ifdef VTK_WORDS_BIGENDIAN
# define vtkSwap4 vtkByteSwap::Swap4LE
# define vtkSwap4Range vtkByteSwap::Swap4LERange
# define vtkSwap8 vtkByteSwap::Swap8LE
# define vtkSwap8Range vtkByteSwap::Swap8LERange
#else
# define vtkSwap4 vtkByteSwap::Swap4BE
# define vtkSwap4Range vtkByteSwap::Swap4BERange
# define vtkSwap8 vtkByteSwap::Swap8BE
# define vtkSwap8Range vtkByteSwap::Swap8BERange
#endif

class vtkClientSocket;
class vtkServerSocket;

class VTKPARALLELCORE_EXPORT vtkSocketCommunicator : public vtkCommunicator
{
public:
  static vtkSocketCommunicator *New();
  vtkTypeMacro(vtkSocketCommunicator,vtkCommunicator);
  void PrintSelf(ostream& os, vtkIndent indent) override;

  //@{
  /**
   * Wait for connection on a given port.
   * These methods return 1 on success, 0 on error.
   */
  virtual int WaitForConnection(int port);
  virtual int WaitForConnection(vtkServerSocket* socket,
    unsigned  long msec = 0);
  //@}

  /**
   * Close a connection.
   */
  virtual void CloseConnection();

  /**
   * Open a connection to host.
   */
  virtual int ConnectTo(const char* hostName, int port);

  //@{
  /**
   * Returns 1 if bytes must be swapped in received ints, floats, etc
   */
  vtkGetMacro(SwapBytesInReceivedData, int);
  //@}

  /**
   * Is the communicator connected?.
   */
  int GetIsConnected();

  /**
   * Set the number of processes you will be using.
   */
  void SetNumberOfProcesses(int num) override;

  //------------------ Communication --------------------

  //@{
  /**
   * Performs the actual communication.  You will usually use the convenience
   * Send functions defined in the superclass.
   */
  int SendVoidArray(const void *data, vtkIdType length, int type,
                            int remoteHandle, int tag) override;
  int ReceiveVoidArray(void *data, vtkIdType length, int type,
                               int remoteHandle, int tag) override;
  //@}

  /**
   * This class foolishly breaks the conventions of the superclass, so this
   * overload fixes the method.
   */
  void Barrier() override;

  //@{
  /**
   * This class foolishly breaks the conventions of the superclass, so the
   * default implementations of these methods do not work.  These just give
   * errors instead.
   */
  int BroadcastVoidArray(void *data, vtkIdType length, int type,
                                 int srcProcessId) override;
  int GatherVoidArray(const void *sendBuffer, void *recvBuffer,
                              vtkIdType length, int type, int destProcessId) override;
  int GatherVVoidArray(const void *sendBuffer, void *recvBuffer,
                               vtkIdType sendLength, vtkIdType *recvLengths,
                               vtkIdType *offsets, int type, int destProcessId) override;
  int ScatterVoidArray(const void *sendBuffer, void *recvBuffer,
                               vtkIdType length, int type, int srcProcessId) override;
  int ScatterVVoidArray(const void *sendBuffer, void *recvBuffer,
                                vtkIdType *sendLengths, vtkIdType *offsets,
                                vtkIdType recvLength, int type,
                                int srcProcessId) override;
  int AllGatherVoidArray(const void *sendBuffer, void *recvBuffer,
                                 vtkIdType length, int type) override;
  int AllGatherVVoidArray(const void *sendBuffer, void *recvBuffer,
                                  vtkIdType sendLength, vtkIdType *recvLengths,
                                  vtkIdType *offsets, int type) override;
  int ReduceVoidArray(const void *sendBuffer, void *recvBuffer,
                              vtkIdType length, int type,
                              int operation, int destProcessId) override;
  int ReduceVoidArray(const void *sendBuffer, void *recvBuffer,
                              vtkIdType length, int type,
                              Operation *operation, int destProcessId) override;
  int AllReduceVoidArray(const void *sendBuffer, void *recvBuffer,
                                 vtkIdType length, int type,
                                 int operation) override;
  int AllReduceVoidArray(const void *sendBuffer, void *recvBuffer,
                                 vtkIdType length, int type,
                                 Operation *operation) override;
  //@}

  //@{
  /**
   * Set or get the PerformHandshake ivar. If it is on, the communicator
   * will try to perform a handshake when connected.
   * It is on by default.
   */
  vtkSetClampMacro(PerformHandshake, int, 0, 1);
  vtkBooleanMacro(PerformHandshake, int);
  vtkGetMacro(PerformHandshake, int);
  //@}

  //@{
  /**
   * Get/Set the output stream to which communications should be
   * logged.  This is intended as a debugging feature.
   */
  virtual void SetLogStream(ostream* stream);
  virtual ostream* GetLogStream();
  //@}

  //@{
  /**
   * Log messages to the given file.  The file is truncated unless the
   * second argument is non-zero (default is to truncate).  If the
   * file name is empty or nullptr, logging is disabled.  Returns 0 if
   * the file failed to open, and 1 otherwise.
   */
  virtual int LogToFile(const char* name);
  virtual int LogToFile(const char* name, int append);
  //@}

  //@{
  /**
   * If ReportErrors if false, all vtkErrorMacros are suppressed.
   */
  vtkSetMacro(ReportErrors, int);
  vtkGetMacro(ReportErrors, int);
  //@}

  //@{
  /**
   * Get/Set the actual socket used for communication.
   */
  vtkGetObjectMacro(Socket, vtkClientSocket);
  void SetSocket(vtkClientSocket*);
  //@}

  /**
   * Performs handshake. This uses vtkClientSocket::ConnectingSide to decide
   * whether to perform ServerSideHandshake or ClientSideHandshake.
   */
  int Handshake();

  /**
   * Performs ServerSide handshake.
   * One should preferably use Handshake() which calls ServerSideHandshake or
   * ClientSideHandshake as required.
   */
  int ServerSideHandshake();

  /**
   * Performs ClientSide handshake.
   * One should preferably use Handshake() which calls ServerSideHandshake or
   * ClientSideHandshake as required.
   */
  int ClientSideHandshake();

  //@{
  /**
   * Returns true if this side of the socket is the server.  The result
   * is invalid if the socket is not connected.
   */
  vtkGetMacro(IsServer, int);
  //@}

  /**
   * Uniquely identifies the version of this class.  If the versions match,
   * then the socket communicators should be compatible.
   */
  static int GetVersion();

  /**
   * This flag is cleared before vtkCommand::WrongTagEvent is fired when ever a
   * message with mismatched tag is received. If the handler wants the message
   * to be buffered for later use, it should set this flag to true. In which
   * case the vtkSocketCommunicator will buffer the message and it will be
   * automatically processed the next time one does a ReceiveTagged() with a
   * matching tag.
   */
  void BufferCurrentMessage()
    { this->BufferMessage = true; }

  /**
   * Returns true if there are any messages in the receive buffer.
   */
  bool HasBufferredMessages();

protected:

  vtkClientSocket* Socket;
  int SwapBytesInReceivedData;
  int RemoteHas64BitIds;
  int PerformHandshake;
  int IsServer;

  int ReportErrors;

  ofstream* LogFile;
  ostream* LogStream;

  vtkSocketCommunicator();
  ~vtkSocketCommunicator() override;

  // Wrappers around send/recv calls to implement loops.  Return 1 for
  // success, and 0 for failure.
  int SendTagged(const void* data, int wordSize, int numWords, int tag,
                 const char* logName);
  int ReceiveTagged(void* data, int wordSize, int numWords, int tag,
                    const char* logName);
  int ReceivePartialTagged(void* data, int wordSize, int numWords, int tag,
                    const char* logName);

  int ReceivedTaggedFromBuffer(
    void* data, int wordSize, int numWords, int tag, const char* logName);

  /**
   * Fix byte order for received data.
   */
  void FixByteOrder(void* data, int wordSize, int numWords);

  // Internal utility methods.
  void LogTagged(const char* name, const void* data, int wordSize, int numWords,
                 int tag, const char* logName);
  int CheckForErrorInternal(int id);
  bool BufferMessage;
private:
  vtkSocketCommunicator(const vtkSocketCommunicator&) = delete;
  void operator=(const vtkSocketCommunicator&) = delete;

  int SelectSocket(int socket, unsigned long msec);

  // SwapBytesInReceiveData needs an invalid / not set.
  // This avoids checking length of endian handshake.
  enum ErrorIds {
    SwapOff = 0,
    SwapOn,
    SwapNotSet
  };

  // One may be tempted to change this to a vtkIdType, but really an int is
  // enough since we split messages > VTK_INT_MAX.
  int TagMessageLength;

  //  Buffer to save messages received with different tag than requested.
  class vtkMessageBuffer;
  vtkMessageBuffer* ReceivedMessageBuffer;

};

#endif
