#!/bin/bash

set -e

if [ "mpich" != "serial" ]; then
  update-alternatives \
	--install /usr/bin/h5pcc h5pcc /usr/bin/h5pcc.mpich 10 \
	--slave /usr/bin/h5pfc h5pfc /usr/bin/h5pfc.mpich \
	--slave /usr/share/man/man1/h5pcc.1.gz h5pcc.1.gz /usr/share/man/man1/h5pcc.mpich.1.gz \
	--slave /usr/share/man/man1/h5pfc.1.gz h5pfc.1.gz /usr/share/man/man1/h5pfc.mpich.1.gz
fi
update-alternatives \
	--install /usr/lib/x86_64-linux-gnu/pkgconfig/hdf5.pc hdf5.pc /usr/lib/x86_64-linux-gnu/pkgconfig/hdf5_mpich.pc 10 \
	--slave /usr/lib/x86_64-linux-gnu/pkgconfig/hdf5_hl.pc hdf5_hl.pc /usr/lib/x86_64-linux-gnu/pkgconfig/hdf5_mpich_hl.pc \
	--slave /usr/lib/x86_64-linux-gnu/pkgconfig/hdf5_hl_fortran.pc hdf5_hl_fortran.pc /usr/lib/x86_64-linux-gnu/pkgconfig/hdf5_mpich_hl_fortran.pc \
	--slave /usr/lib/x86_64-linux-gnu/pkgconfig/hdf5_fortran.pc hdf5_fortran.pc /usr/lib/x86_64-linux-gnu/pkgconfig/hdf5_mpich_fortran.pc \
	--slave /usr/lib/x86_64-linux-gnu/pkgconfig/hdf5_cpp.pc hdf5_cpp.pc /usr/lib/x86_64-linux-gnu/pkgconfig/hdf5_mpich_cpp.pc \
	--slave /usr/lib/x86_64-linux-gnu/pkgconfig/hdf5_hl_cpp.pc hdf5_hl_cpp.pc /usr/lib/x86_64-linux-gnu/pkgconfig/hdf5_mpich_hl_cpp.pc
update-alternatives \
	--install /usr/lib/x86_64-linux-gnu/cmake/hdf5 hdf5.cmake /usr/lib/x86_64-linux-gnu/cmake/hdf5_mpich 10

# Transitionning from hdf5-mpich.pc to hdf5_mpich.pc
if update-alternatives --list hdf5.pc | grep -q '/hdf5-mpich\.pc'; then
  current_status=$(update-alternatives --query hdf5.pc | grep '^Status: ' | cut -d ' '  -f 2)
  current_value=$(update-alternatives --query hdf5.pc | grep '^Value: ' | cut -d ' '  -f 2)
  if [ "$current_status" != auto ] && [ "${current_value##*/}" = hdf5-mpich.pc ]; then
    update-alternatives --set hdf5.pc /usr/lib/x86_64-linux-gnu/pkgconfig/hdf5_mpich.pc
  fi
  update-alternatives --remove hdf5.pc /usr/lib/x86_64-linux-gnu/pkgconfig/hdf5-mpich.pc
fi

# We drop support for hdf5-mpi.pc as a slave of the 'mpi' alternatives
# This is too complex and faulty
# See #953021 and #968559 for references
#
# There is no way to simply add a new slave. We must parse the existing
# mpi alternatives, then reinstall the whole related alternative plus the
# wanted --slave part
function read_alt_slaves () {
  # See #973261
  local -n slaves=$1
  set -- $(echo "$2" | sed -n '/Slaves:/{: while;n;s/^ //;T end;p;b while;: end;q}')
  while [ -n "$1" ]; do
    slaves["$1"]="$2"
    shift 2
  done
}

if [ "mpich" != "serial" ]; then
  # Parse existing mpi alternatives
  mpi_alt=$(update-alternatives --query mpi)
  mpi_alt_sig=$(echo "$mpi_alt" | sed '/^$/q')
  mpi_alt_impl=$(echo "$mpi_alt" | sed -n -e '\!^Alternative: /usr/bin/mpicc.mpich!p' -e '0,\!^Alternative: /usr/bin/mpicc.mpich!d' -e '/^$/q' -e 'p')
  mpi_impl_priority=$(echo "$mpi_alt_impl" | sed -n '/^Priority: /{s/Priority: \(.*\)$/\1/;p}')
  declare -A slave_links slave_targets
  read_alt_slaves slave_links "$mpi_alt_sig"
  read_alt_slaves slave_targets "$mpi_alt_impl"
  # At this point:
  # * slave_links holds all the slaves name,link pairs
  # * slave_targets holds all the slaves name,target pairs for our mpi flavor
  #
  # If there is a 'hdf5-mpi.pc' key, the slave need to be removed
  if grep -E '(^| )hdf5-mpi\.pc( |$)' <<<"${!slave_targets[@]}"; then
    # Construct the slaves related part of the update-alternatives command
    current_slaves=
    for key in "${!slave_targets[@]}"; do
      # Do not keep the 'hdf5-mpi.pc' slave
      if [ "$key" = "hdf5-mpi.pc" ]; then
        continue
      fi
      current_slaves="$current_slaves --slave ${slave_links[$key]} $key ${slave_targets[$key]}"
    done
    # Re-install the whole alternative without our 'hdf5-*.pc' slave
    update-alternatives --install /usr/bin/mpicc mpi /usr/bin/mpicc.mpich "$mpi_impl_priority" $current_slaves
  fi

  # Drop the hdf5-mpi.pc choice from the hdf5.pc alternatives if present
  if update-alternatives --list hdf5.pc | grep '/hdf5-mpi.pc$'; then
    update-alternatives --remove hdf5.pc /usr/lib/x86_64-linux-gnu/pkgconfig/hdf5-mpi.pc
  fi
fi



exit 0