class Mpich < Formula
  desc "Implementation of the MPI Message Passing Interface standard"
  homepage "https://www.mpich.org/"
  url "https://www.mpich.org/static/downloads/3.4.2/mpich-3.4.2.tar.gz"
  mirror "https://fossies.org/linux/misc/mpich-3.4.2.tar.gz"
  sha256 "5c19bea8b84e8d74cca5f047e82b147ff3fba096144270e3911ad623d6c587bf"
  license "mpich2"

  livecheck do
    url "https://www.mpich.org/static/downloads/"
    regex(%r{href=.*?v?(\d+(?:\.\d+)+)/?["' >]}i)
  end

  bottle do
    sha256 cellar: :any,                 arm64_big_sur: "8c79cf6b224e90fbe5fbe111cdafb03d1b54f8f4a88c32a157af6d3ea29de7c4"
    sha256 cellar: :any,                 big_sur:       "23d95423962812214194ca039fdd2d7dcca76626d291e02566989460b748a8df"
    sha256 cellar: :any,                 catalina:      "3d5324ae766872fb9c2d6229ea97f49930c6a8239e38cc89bf5fb6a8f71d88d4"
    sha256 cellar: :any,                 mojave:        "80d73225cb6e7242190049addb88898f920991a637f6dd7af07f13ffa28095fd"
    sha256 cellar: :any_skip_relocation, x86_64_linux:  "36cc3d6dc61cf19eeea37e07ce456200353b034c89952abc89e8999e2c198274"
  end

  head do
    url "https://github.com/pmodels/mpich.git"

    depends_on "autoconf" => :build
    depends_on "automake" => :build
    depends_on "libtool"  => :build
  end

  depends_on "gcc" # for gfortran
  depends_on "hwloc"

  on_macos do
    conflicts_with "libfabric", because: "both install `fabric.h`"
  end

  on_linux do
    # Can't be enabled on mac:
    # https://lists.mpich.org/pipermail/discuss/2021-May/006192.html
    depends_on "libfabric"
  end

  conflicts_with "open-mpi", because: "both install MPI compiler wrappers"

  if Hardware::CPU.arm?
    # gfortran from 10.2.0 on arm64 does not seem to know about real128 and complex128
    # the recommended solution by upstream is to comment out the declaration of
    # real128 and complex128 in the source code as they do not have the resources
    # to update the f08 binding generation script at the moment
    # https://lists.mpich.org/pipermail/discuss/2021-March/006167.html
    patch :DATA
  end

  def install
    if build.head?
      # ensure that the consistent set of autotools built by homebrew is used to
      # build MPICH, otherwise very bizarre build errors can occur
      ENV["MPICH_AUTOTOOLS_DIR"] = HOMEBREW_PREFIX + "bin"
      system "./autogen.sh"
    end

    args = %W[
      --disable-dependency-tracking
      --enable-fast=all,O3
      --enable-g=dbg
      --enable-romio
      --enable-shared
      --with-pm=hydra
      FC=gfortran-#{Formula["gcc"].any_installed_version.major}
      F77=gfortran-#{Formula["gcc"].any_installed_version.major}
      --disable-silent-rules
      --prefix=#{prefix}
      --mandir=#{man}
    ]

    # Flag for compatibility with GCC 10
    # https://lists.mpich.org/pipermail/discuss/2020-January/005863.html
    args << "FFLAGS=-fallow-argument-mismatch"
    args << "CXXFLAGS=-Wno-deprecated"
    args << "CFLAGS=-fgnu89-inline -Wno-deprecated"

    if OS.linux?
      # Use libfabric https://lists.mpich.org/pipermail/discuss/2021-January/006092.html
      args << "--with-device=ch4:ofi"
      args << "--with-libfabric=#{Formula["libfabric"].opt_prefix}"
    end

    system "./configure", *args

    system "make"
    system "make", "install"
  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", "-np", "4", "./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", "-np", "4", "./hellof"
  end
end

__END__
--- a/src/binding/fortran/use_mpi_f08/mpi_f08_types.f90
+++ b/src/binding/fortran/use_mpi_f08/mpi_f08_types.f90
@@ -248,10 +248,8 @@
     module procedure MPI_Sizeof_xint64
     module procedure MPI_Sizeof_xreal32
     module procedure MPI_Sizeof_xreal64
-    module procedure MPI_Sizeof_xreal128
     module procedure MPI_Sizeof_xcomplex32
     module procedure MPI_Sizeof_xcomplex64
-    module procedure MPI_Sizeof_xcomplex128
 end interface
 
 private :: MPI_Sizeof_character
@@ -263,10 +261,8 @@
 private :: MPI_Sizeof_xint64
 private :: MPI_Sizeof_xreal32
 private :: MPI_Sizeof_xreal64
-private :: MPI_Sizeof_xreal128
 private :: MPI_Sizeof_xcomplex32
 private :: MPI_Sizeof_xcomplex64
-private :: MPI_Sizeof_xcomplex128
 
 contains
 
@@ -350,16 +346,6 @@
     ierror = 0
 end subroutine MPI_Sizeof_xreal64
 
-subroutine MPI_Sizeof_xreal128 (x, size, ierror)
-    use,intrinsic :: iso_fortran_env, only: real128
-    real(real128),dimension(..) :: x
-    integer, intent(out) :: size
-    integer, optional,  intent(out) :: ierror
-
-    size = storage_size(x)/8
-    ierror = 0
-end subroutine MPI_Sizeof_xreal128
-
 subroutine MPI_Sizeof_xcomplex32 (x, size, ierror)
     use,intrinsic :: iso_fortran_env, only: real32
     complex(real32),dimension(..) :: x
@@ -380,16 +366,6 @@
     ierror = 0
 end subroutine MPI_Sizeof_xcomplex64
 
-subroutine MPI_Sizeof_xcomplex128 (x, size, ierror)
-    use,intrinsic :: iso_fortran_env, only: real128
-    complex(real128),dimension(..) :: x
-    integer, intent(out) :: size
-    integer, optional,  intent(out) :: ierror
-
-    size = storage_size(x)/8
-    ierror = 0
-end subroutine MPI_Sizeof_xcomplex128
-
 subroutine MPI_Status_f2f08(f_status, f08_status, ierror)
     integer, intent(in) :: f_status(MPI_STATUS_SIZE)
     type(MPI_Status), intent(out) :: f08_status