/*
 * Copyright (C) 2005-2020 Centre National d'Etudes Spatiales (CNES)
 *
 * This file is part of Orfeo Toolbox
 *
 *     https://www.orfeo-toolbox.org/
 *
 * Licensed 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.
 */

#include "otbMPIConfig.h"

#include <exception>
#include <cstdlib>
#include <iostream>
#include <sstream>
#include <string>
#include <cassert>

#if defined(__GNUC__) || defined(__clang__)
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wunused-parameter"
#pragma GCC diagnostic ignored "-Wcast-align"
#include <mpi.h>
#pragma GCC diagnostic pop
#else
#include <mpi.h>
#endif


/**
  * Call the MPI routine MPIFunc with arguments Args (surrounded by
  * parentheses). If the result is not MPI_SUCCESS, throw an exception.
  */
#define OTB_MPI_CHECK_RESULT(MPIFunc, Args)                                 \
  {                                                                         \
    int _result = MPIFunc Args;                                             \
    if (_result != MPI_SUCCESS)                                             \
    {                                                                       \
      std::stringstream message;                                            \
      message << "otb::ERROR: " << #MPIFunc << " (Code = " << _result;      \
      ::itk::ExceptionObject _e(__FILE__, __LINE__, message.str().c_str()); \
      throw _e;                                                             \
    }                                                                       \
  }


namespace otb
{

/** Initialize the singleton */
MPIConfig::Pointer MPIConfig::m_Singleton = NULL;

MPIConfig::Pointer MPIConfig::Instance()
{
  if (m_Singleton.GetPointer() == NULL)
  {
    m_Singleton = itk::ObjectFactory<Self>::Create();

    if (m_Singleton.GetPointer() == NULL)
    {
      m_Singleton = new MPIConfig;
    }
    m_Singleton->UnRegister();
  }

  return m_Singleton;
}


/** CreateInitialize MPI environment */
MPIConfig::MPIConfig() : m_MyRank(-1), m_NbProcs(0), m_abortOnException(true), m_initialized(false), m_terminated(false)
{
}

/** Shuts down the MPI environment. */
MPIConfig::~MPIConfig()
{
  terminate();
}

/** Initialize MPI environment */
void MPIConfig::Init(int& argc, char**& argv, bool abortOnException)
{
  if (!m_terminated)
  {
    // Abort on exception
    m_abortOnException = abortOnException;
    // Initialize
    int initialized;
    OTB_MPI_CHECK_RESULT(MPI_Initialized, (&initialized));
    m_initialized = (initialized == 1);
    if (!m_initialized)
    {
      OTB_MPI_CHECK_RESULT(MPI_Init, (&argc, &argv));
      m_initialized = true;
    }
    // Get MPI rank
    int irank = 0;
    OTB_MPI_CHECK_RESULT(MPI_Comm_rank, (MPI_COMM_WORLD, &irank));

    if (irank < 0)
    {
      logError("Negative MPI rank");
      abort(EXIT_FAILURE);
    }

    m_MyRank = static_cast<unsigned int>(irank);

    // Get MPI NbProocs

    int inbprocs = 0;

    OTB_MPI_CHECK_RESULT(MPI_Comm_size, (MPI_COMM_WORLD, &inbprocs));

    if (inbprocs < 1)
    {
      logError("Negative or null number of processes");
      abort(EXIT_FAILURE);
    }

    m_NbProcs = static_cast<unsigned int>(inbprocs);
  }
}

/** Shuts down the MPI environment. */
void MPIConfig::terminate()
{
  if (m_initialized && !m_terminated)
  {
    if (std::uncaught_exception() && m_abortOnException)
    {
      abort(EXIT_FAILURE);
    }
    else
    {
      int finalized;
      OTB_MPI_CHECK_RESULT(MPI_Finalized, (&finalized));
      if (!finalized)
      {
        OTB_MPI_CHECK_RESULT(MPI_Finalize, ());
      }
    }
    m_terminated = true;
  }
}

void MPIConfig::abort(int errCode)
{
  OTB_MPI_CHECK_RESULT(MPI_Abort, (MPI_COMM_WORLD, errCode));
}

void MPIConfig::barrier()
{
  OTB_MPI_CHECK_RESULT(MPI_Barrier, (MPI_COMM_WORLD));
}

void MPIConfig::logError(const std::string message)
{
  if (m_MyRank == 0)
  {
    std::cerr << message << std::endl;
  }
}

void MPIConfig::logInfo(const std::string message)
{
  if (m_MyRank == 0)
  {
    std::cout << message << std::endl;
  }
}

} // End namespace otb
