cmake_minimum_required(VERSION 3.8)
project(TestFindMPI NONE)
include(CTest)

macro(source_code_mapper_helper LANG_NAME)
  if("${LANG_NAME}" STREQUAL "C")
    set(MPITEST_SOURCE_FILE "main.c")
  elseif("${LANG_NAME}" STREQUAL "CXX")
    configure_file("main.c" "main.cxx" COPYONLY)
    set(MPITEST_SOURCE_FILE "main.cxx")
  elseif("${LANG_NAME}" STREQUAL "Fortran")
    set(MPITEST_SOURCE_FILE "main.f90")
  endif()
endmacro()

foreach(c C CXX Fortran)
  if("${MPI_TEST_${c}}")
    message("Testing ${c}")
    enable_language(${c})
  endif()
endforeach()

set(MPI_CXX_SKIP_MPICXX TRUE)
set(MPI_CXX_VALIDATE_SKIP_MPICXX TRUE)
find_package(MPI REQUIRED)

foreach(c C CXX Fortran)
  if(NOT "${MPI_TEST_${c}}")
    continue()
  endif()
  if(${c} STREQUAL CXX AND MPI_MPICXX_FOUND)
    message(FATAL_ERROR "Could not suppress MPI-2 C++ bindings for this MPI.")
  endif()
  source_code_mapper_helper(${c})
  add_executable(test_tgt_${c} ${MPITEST_SOURCE_FILE})
  target_link_libraries(test_tgt_${c} MPI::MPI_${c})
  add_test(NAME test_tgt_${c} COMMAND test_tgt_${c})

  add_executable(test_var_${c} ${MPITEST_SOURCE_FILE})
  target_include_directories(test_var_${c} PRIVATE "${MPI_${c}_INCLUDE_PATH}")
  target_link_libraries(test_var_${c} PRIVATE "${MPI_${c}_LINK_FLAGS}" "${MPI_${c}_LIBRARIES}")
  set(copied_MPI_${c}_OPTIONS "${MPI_${c}_COMPILE_FLAGS}")
  separate_arguments(copied_MPI_${c}_OPTIONS)
  target_compile_options(test_var_${c} PRIVATE "${copied_MPI_${c}_OPTIONS}")
  add_test(NAME test_var_${c} COMMAND test_var_${c})
endforeach()