#!/bin/bash

set -e

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 [ "$1" != "upgrade" ]; then
  if [ "mpich" != "serial" ]; then
    update-alternatives \
	--remove h5pcc /usr/bin/h5pcc.mpich
  fi
  update-alternatives \
	--remove hdf5.pc /usr/lib/x86_64-linux-gnu/pkgconfig/hdf5-mpich.pc

  # Remove the slave hdf5-mpi.pc from the related 'mpi' flavor alternative
  # See #953021
  # There is no way to simply remove slave. We must parse the existing
  # mpi alternatives, then reinstall the whole related alternative minus
  # the unwanted --slave part
  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 "$mpi_alt_impl"
    # At this point:
    # * slave_links holds all the slaves name,link pairs
    # * slave_targets holds all the slaves name,target pairs for our mpi flavor
    # Construct the slaves related part of the update-alternatives command
    current_slaves=
    for key in "${!slave_targets[@]}"; do
      # Do not keep the 'hdf5-mpi.pc' slave (we want it removed)
      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 minus our 'hdf5-mpi.pc' slave
    update-alternatives --install /usr/bin/mpicc mpi /usr/bin/mpicc.mpich "$mpi_impl_priority" $current_slaves

    # Finally, re-parse the mpi alternatives
    # If there is no 'hdf5-mpi.pc' slave left we have to remove this choice from
    # the hdf5.pc alternatives
    mpi_alt=$(update-alternatives --query mpi)
    mpi_alt_sig=$(echo "$mpi_alt" | sed '/^$/q')
    declare -A slave_links_left
    read_alt_slaves slave_links_left "$mpi_alt_sig"
    if [ -z "${slave_links_left[hdf5-mpi.pc]}" ]; then
      update-alternatives --remove hdf5.pc /usr/lib/x86_64-linux-gnu/pkgconfig/hdf5-mpi.pc
    fi
  fi
fi



exit 0