class OpenMpi < Formula
  desc "High performance message passing library"
  homepage "https://www.open-mpi.org/"
  url "https://download.open-mpi.org/release/open-mpi/v4.0/openmpi-4.0.0.tar.bz2"
  sha256 "2f0b8a36cfeb7354b45dda3c5425ef8393c9b04115570b615213faaa3f97366b"

  bottle do
    sha256 "144bf979a8e13639714b4d0b55a4f7a49b74f4942fc655b29c8cc56879d3e95e" => :mojave
    sha256 "ba0dbe6719d413637ad2fa1557126c88bc0ac49191e4efefea75508de568311a" => :high_sierra
    sha256 "b862fdf7f2c21dddc9e7e1f180622f9a398cb76091cb84fb2181cead9073eb6f" => :sierra
  end

  head do
    url "https://github.com/open-mpi/ompi.git"
    depends_on "autoconf" => :build
    depends_on "automake" => :build
    depends_on "libtool" => :build
  end

  option "with-cxx-bindings", "Enable C++ MPI bindings (deprecated as of MPI-3.0)"

  depends_on "gcc"
  depends_on "libevent"

  conflicts_with "mpich", :because => "both install MPI compiler wrappers"

  needs :cxx11

  def install
    # otherwise libmpi_usempi_ignore_tkr gets built as a static library
    ENV["MACOSX_DEPLOYMENT_TARGET"] = MacOS.version

    ENV.cxx11

    args = %W[
      --prefix=#{prefix}
      --disable-dependency-tracking
      --disable-silent-rules
      --enable-ipv6
      --with-libevent=#{Formula["libevent"].opt_prefix}
      --with-sge
    ]
    args << "--with-platform-optimized" if build.head?
    args << "--enable-mpi-cxx" if build.with? "cxx-bindings"
    # fixes an issue in 4.0.0, should be fixed in 4.0.1
    args << "--enable-mpi1-compatibility"

    system "./autogen.pl" if build.head?
    system "./configure", *args
    system "make", "all"
    system "make", "check"
    system "make", "install"

    # Fortran bindings install stray `.mod` files (Fortran modules) in `lib`
    # that need to be moved to `include`.
    include.install Dir["#{lib}/*.mod"]
  end

  test do
    (testpath/"hello.c").write <<~EOS
      #include <mpi.h>
      #include <stdio.h>

      int main()
      {
        int size, rank, nameLen;
        char name[MPI_MAX_PROCESSOR_NAME];
        MPI_Init(NULL, NULL);
        MPI_Comm_size(MPI_COMM_WORLD, &size);
        MPI_Comm_rank(MPI_COMM_WORLD, &rank);
        MPI_Get_processor_name(name, &nameLen);
        printf("[%d/%d] Hello, world! My name is %s.\\n", rank, size, name);
        MPI_Finalize();
        return 0;
      }
    EOS
    system bin/"mpicc", "hello.c", "-o", "hello"
    system "./hello"
    system bin/"mpirun", "./hello"
    (testpath/"hellof.f90").write <<~EOS
      program hello
      include 'mpif.h'
      integer rank, size, ierror, tag, status(MPI_STATUS_SIZE)
      call MPI_INIT(ierror)
      call MPI_COMM_SIZE(MPI_COMM_WORLD, size, ierror)
      call MPI_COMM_RANK(MPI_COMM_WORLD, rank, ierror)
      print*, 'node', rank, ': Hello Fortran world'
      call MPI_FINALIZE(ierror)
      end
    EOS
    system bin/"mpif90", "hellof.f90", "-o", "hellof"
    system "./hellof"
    system bin/"mpirun", "./hellof"
  end
end