switches

function switch-tl-to ()
{
  new_target="$1"

  # I think that all other TL-related files symlink through here.
  # e.g.,
  # /opt/texbin: symbolic link to /usr/local/texlive/2022/bin/x86_64-linux
  #
  # To check for more such symlinks, can use the following command:
  # (https://unix.stackexchange.com/q/301717/197212)
  # find / -type l -exec readlink -nf {} ';' -exec echo " -> {}" ';' | grep "/usr/local/texlive"
  main_tl_dir_parent="/usr/local/texlive"
  main_tl_dir="${main_tl_dir_parent}/tl"

  if [ ! -L "${main_tl_dir}" ]; then
    echo "Error: Not a symbolic link. Needs setup." >&2
    return 1
  fi

  if [ ! -d "${main_tl_dir_parent}/${new_target}" ]; then
    echo "Error: the directory ${main_tl_dir_parent}/${new_target} does not exist."
    return 1
  fi

  # This is just an optimization to get an early return so we don't need to
  # rerun fc-cache.
  #
  current_target="$( readlink "${main_tl_dir}")"
  if [ "${current_target}" = "${new_target}" ]; then
    # nothing to be done
    return 0
  fi

  # sanity check that the target dir is a valid TL dir
  expected_tlmgr="${main_tl_dir_parent}/${new_target}/bin/x86_64-linux/tlmgr"
  # use '*' to match "x86_64-linux"
  if [ ! -e "${expected_tlmgr}"  ]; then
    echo "Error: In the new target, ${new_target}, tlmgr is not found in the expected location: ${expected_tlmgr}." >&2
    return 1
  fi

  sudo rm "${main_tl_dir}"
  sudo ln -s "${new_target}" "${main_tl_dir}"

  # TODO: tell users they can remove this file and run "sudo fc-cache -fsv"
  # and then this command won't be run anymore.
  if [ -e "/etc/fonts/conf.d/09-texlive.conf" ]; then
    # This is because we set up the *system* fonts to be able to use TeX Live fonts.
    # See this file: /etc/fonts/conf.d/09-texlive.conf
    # You can see that the fonts are being used by looking at "sudo lsof".
    # For example, search for NotoSans-Regular.ttf.
    #
    # Although in the file 09-texlive.conf it is a path through the 'tl' link, I
    # think when those paths are processed the *absolute* path is what is
    # stored/cached, so we have to update those paths when we change the symlink.
    echo "Running fc-cache to update system font reference..."
    sudo fc-cache -fsv >/dev/null 2>&1
    fc_cache_ret=$?
    if [ "${fc_cache_ret}" != "0" ]; then
      echo "ERROR: fc-cache -fsv exited with error." >&2
    fi
    echo "Running fc-cache to update system font reference...Done."
  fi

  \sudo -k
}
_switch_tl_to()
{
  local cur

  cur=${COMP_WORDS[COMP_CWORD]}

  if [ "$COMP_CWORD" == "1" ]; then
    # the "--hide=tl" hides the "tl" symlink.
    COMPREPLY=( $( compgen -W '`ls --hide=tl /usr/local/texlive/`' -- $cur ) )
  fi
}
complete -F _switch_tl_to ${filenames:-} switch-tl-to


function switch-sys-fonts-to-tl ()
{
  SYSFONT='/etc/fonts/conf.d/09-texlive.conf'
  if sudo cp "$(kpsewhich -var-value TEXMFSYSVAR)/fonts/conf/texlive-fontconfig.conf" "${SYSFONT}" \
    > /dev/null 2>&1; then
    echo "finished copying."
  else
    echo "Error: could not copy the font config to the system font directory."
  fi
  sudo fc-cache -fsv

  \sudo -k
}


function switch-sys-fonts-to-ubuntu ()
{
  # These LyX ctests are still expected to fail because of missing fonts.
  #         434 - export/export/latex/languages/en-th_utf8_pdf4_systemF (Failed)
  #         485 - DEFAULTOUTPUT_export/export/latex/languages/supported-languages_polyglossia-XeTeX_pdf4_systemF (Failed)

  SYSFONT='/etc/fonts/conf.d/09-texlive.conf'
  sudo rm "${SYSFONT}"
  sudo fc-cache -fsv

  \sudo -k
}