include(FindPkgConfig)

macro(enable_mpi _FLAGS_ _INC_DIRS_ _LIBS_)
    if (${ARGC} GREATER 3)
      set(LINK_EXECUTABLE ON)
    else ()
      set(LINK_EXECUTABLE OFF)
    endif ()

    find_package(MPI REQUIRED)
    list(APPEND ${_INC_DIRS_} ${MPI_CXX_INCLUDE_PATH})
    list(APPEND ${_FLAGS_}    ${MPI_CXX_COMPILE_FLAGS})

    if (LINK_EXECUTABLE)
      string(STRIP " ${MPI_CXX_LINK_FLAGS} " MPI_CXX_LINK_FLAGS_)
      list(APPEND ${_FLAGS_} ${MPI_CXX_LINK_FLAGS_})
      list(APPEND ${_LIBS_}  ${MPI_CXX_LIBRARIES})
    endif (LINK_EXECUTABLE)
endmacro(enable_mpi)


macro(enable_petsc _FLAGS_ _INC_DIRS_ _LIBS_)
    if (${ARGC} GREATER 3)
      set(LINK_EXECUTABLE ON)
    else ()
      set(LINK_EXECUTABLE OFF)
    endif ()

    # PETSc library is required
    find_file(PETSC_PKG_CONFIG "PETSc.pc"
      HINTS ${PETSC_DIR}/lib/pkgconfig
            $ENV{PETSC_DIR}/lib/pkgconfig
            ${PETSC_ROOT}/lib/pkgconfig
            $ENV{PETSC_ROOT}/lib/pkgconfig
            /usr/lib/petsc/lib/pkgconfig
            /usr/lib/petsc/linux-gnu-cxx-opt/lib/pkgconfig
            /usr/lib/petsc/linux-gnu-c-opt/lib/pkgconfig)
    if (PETSC_PKG_CONFIG)
      get_filename_component(PETSC_PKG_CONFIG_PATH "${PETSC_PKG_CONFIG}" PATH CACHE)
      set(ENV{PKG_CONFIG_PATH} ${PETSC_PKG_CONFIG_PATH})
      pkg_check_modules(PETSC REQUIRED PETSc>=3.3)
      set(PETSC_DEFINITIONS ${PETSC_CFLAGS} ${PETSC_CFLAGS_OTHER})
    endif (PETSC_PKG_CONFIG)

    # check whether PETSc installation and configuration is valid
    if (NOT PETSC_INCLUDE_DIRS)
      set(PETSC_VALID ON)
    else ()
      find_file(PETSC_HEADER_FILE "petsc.h" PATHS ${PETSC_INCLUDE_DIRS} NO_DEFAULT_PATH)
      if (PETSC_HEADER_FILE)
        set(PETSC_VALID ON)
      else ()
        set(PETSC_VALID OFF)
      endif ()
    endif (NOT PETSC_INCLUDE_DIRS)

    # if not valid, search again
    if (NOT PETSC_VALID)
      find_package(PETSc REQUIRED)
      set(PETSC_INCLUDE_DIRS ${PETSC_INCLUDES})
      set(PETSC_LIBRARY_DIRS ${PETSC_LIB_DIR})
      message(STATUS "  Found PETSc, version ${PETSC_VERSION}")
    endif (NOT PETSC_VALID)

    list(APPEND ${_INC_DIRS_} ${PETSC_INCLUDE_DIRS})
    list(APPEND ${_FLAGS_} "-DHAVE_PARALLEL_PETSC=1" "-DPETSC_VERSION=${PETSC_VERSION}" ${PETSC_DEFINITIONS})

    if (LINK_EXECUTABLE)
      link_directories(${PETSC_LIBRARY_DIRS})
      list(APPEND ${_LIBS_} ${PETSC_LIBRARIES})
    endif (LINK_EXECUTABLE)


    # parmetis is required
    find_file(PARMETIS_HEADER_FILE "parmetis.h"
      HINTS ${PARMETIS_DIR}/include ${PETSC_INCLUDE_DIRS} /usr/include/parmetis)
    if (PARMETIS_HEADER_FILE)
      get_filename_component(PARMETIS_INCLUDE_PATH "${PARMETIS_HEADER_FILE}" PATH CACHE)
      list(APPEND ${_INC_DIRS_} ${PARMETIS_INCLUDE_PATH})
    else()
      message(FATAL_ERROR "Could not find ParMetis header file 'parmetis.h'!")
    endif (PARMETIS_HEADER_FILE)

    if (LINK_EXECUTABLE)
      find_library(PARMETIS_LIB parmetis
        HINTS ${PARMETIS_DIR}/lib ${PETSC_LIBRARY_DIRS})
      if (NOT PARMETIS_LIB)
        message(FATAL_ERROR "Could not find the ParMetis libraries needed by amdis")
      endif (NOT PARMETIS_LIB)
      message(STATUS "  Found ParMetis library ${PARMETIS_LIB}")
      list(APPEND ${_LIBS_} ${PARMETIS_LIB})
    endif (LINK_EXECUTABLE)


    # metis is required
    find_file(METIS_HEADER_FILE "metis.h"
      HINTS ${METIS_DIR}/include ${PETSC_INCLUDE_DIRS} /usr/include/metis)
    if (METIS_HEADER_FILE)
      get_filename_component(METIS_INCLUDE_PATH "${METIS_HEADER_FILE}" PATH CACHE)
      list(APPEND ${_INC_DIRS_} ${METIS_INCLUDE_PATH})
    else()
      message(FATAL_ERROR "Could not find Metis header file 'metis.h'!")
    endif (METIS_HEADER_FILE)

    if (LINK_EXECUTABLE)
      find_library(METIS_LIB metis
        HINTS ${METIS_DIR}/lib ${PETSC_LIBRARY_DIRS})
      if (NOT METIS_LIB)
        message(FATAL_ERROR "Could not find the Metis libraries needed by amdis")
      endif (NOT METIS_LIB)
      message(STATUS "  Found Metis library ${METIS_LIB}")
      list(APPEND ${_LIBS_} ${METIS_LIB})
    endif (LINK_EXECUTABLE)


    # blas library is required
    if (LINK_EXECUTABLE)
      find_library(BLAS_LIB
        NAMES blas fblas openblas
        HINTS ${BLAS_DIR}/lib ${PETSC_LIBRARY_DIRS} /usr/lib/openblas-base /usr/lib/atlas-base)
      if (BLAS_LIB)
        set(BLAS_LIBRARIES ${BLAS_LIB})
      else (BLAS_LIB)
        find_package(BLAS REQUIRED)
      endif (BLAS_LIB)
      list(APPEND ${_LIBS_} ${BLAS_LIBRARIES})
    endif (LINK_EXECUTABLE)


    # lapack library is required
    if (LINK_EXECUTABLE)
      find_library(LAPACK_LIB
        NAMES lapack flapack
        HINTS ${LAPACK_DIR}/lib ${PETSC_LIBRARY_DIRS} ${PETSC_DIR}/lib)
      if (LAPACK_LIB)
        set(LAPACK_LIBRARIES ${LAPACK_LIB})
      else (LAPACK_LIB)
        find_package(LAPACK REQUIRED)
      endif (LAPACK_LIB)
      list(APPEND ${_LIBS_} ${LAPACK_LIBRARIES})
    endif (LINK_EXECUTABLE)
endmacro(enable_petsc)