# these functions are useful for switching between dev versions
# and stable versions of certain components.

# running a function when the state is already the version
# the function switches to should be a no-op (with a diagnostic
# message)

function switch-polyglossia-to-dev ()
{

  # Udi pointed out a potential problem:
  #
  #   Note that for example you don't watch the files from polyglossia installed in
  #   "fonts/misc/xetex/fontmapping/polyglossia/"
  #   but they rarely get updated.
  #
  # todo: In these functions we could at least check whether those files in the
  #       repo are different so we are notified when we need to update them.


  # where to archive the TL version
  polyglossia_dev_d="/home/$(logname)/polyglossia"

  # location of TL version
  polyglossia_tl_f="$(/opt/texbin/kpsewhich polyglossia.sty)"
  polyglossia_tl_d="$(dirname "${polyglossia_tl_f}")"
  # check whether link or not link to see whether current is tl or dev.
  if [ -L "${polyglossia_tl_d}" ]; then
    echo "Link exists, so you are already using polyglossia-dev."
    return 0
  else
    # overwrite polyglossia_tl since newer stable version
    sudo mv "${polyglossia_tl_d}" "/home/$(logname)/polyglossia_tl"
    # Use a link to poly-dev. That is, do not copy the directory. That way, we
    # can just do a git pull.
    sudo ln -s "${polyglossia_dev_d}/tex" "${polyglossia_tl_d}"
    # we need to check for possibly new/removed files
    sudo /opt/texbin/mktexlsr

    \sudo -k
  fi
}


function switch-polyglossia-to-stable ()
{
  polyglossia_stable_d="/home/$(logname)/polyglossia_tl"
  polyglossia_tl_f="$(/opt/texbin/kpsewhich polyglossia.sty)"
  polyglossia_tl_d="$(dirname "${polyglossia_tl_f}")"
  if [ -L "${polyglossia_tl_d}" ]; then
    sudo rm "${polyglossia_tl_d}"
    sudo mv "${polyglossia_stable_d}" "${polyglossia_tl_d}"
    sudo /opt/texbin/mktexlsr

    \sudo -k
  else
    echo "Link does not exist, so you are already using polyglossia-stable."
    return 0
  fi
}


# useful to see what the initial state is to know whether to switch back, e.g.,
# in a script that updates the TeX Live installation.
function polyglossia-is-stable ()
{
  polyglossia_stable_d="/home/$(logname)/polyglossia_tl"
  polyglossia_tl_f="$(/opt/texbin/kpsewhich polyglossia.sty)"
  polyglossia_tl_d="$(dirname "${polyglossia_tl_f}")"
  if [ -L "${polyglossia_tl_d}" ]; then
    # 0 = no, not stable
    echo "0"
  else
    # 1 = yes, stable
    echo "1"
  fi
  return 0
}


tl_stable_bu_d="/home/$(logname)/tl-stable-binaries"
tl_texbin_d="/opt/texbin/"
function switch-latex-to-tl-dev ()
{
  if [ ! -e "${tl_stable_bu_d}" ]; then
    mkdir "${tl_stable_bu_d}"
  fi

  # todo: how to find this more generally? could take dir of 'which pdflatex'
  # todo: use the "real" link instead? shouldn't make a difference right?
  # $ readlink -f /opt/texbin
  # /usr/local/texlive/2021/bin/x86_64-linux
  for i in "${tl_texbin_d}"/*-dev; do
    devname="$( basename "${i}")"
    stablename="${devname%-*}"
    if [ $(cat "${tl_texbin_d}/${stablename}" | wc -l) = "2" ]; then
      echo "${stablename} already points to dev"
    else
      echo "${stablename} was calling stable."
      sudo mv "${tl_texbin_d}/${stablename}" "${tl_stable_bu_d}"
      # todo: confirm this?
      # doesn't work. Maybe pdflatex (or pdftex rather) checks the binary name calling it (?)
      # sudo ln -s "${tl_texbin_d}/${devname}" "${tl_texbin_d}/${stablename}"
      echo "#!/usr/bin/bash" | sudo tee "${tl_texbin_d}/${stablename}" > /dev/null
      # need to escape " and $ but not @.
      echo "/opt/texbin/${devname} \"\$@\"" | sudo tee -a "${tl_texbin_d}/${stablename}" > /dev/null
      sudo chmod +x "${tl_texbin_d}/${stablename}"
      echo "  ${stablename} now pointing to dev."

      \sudo -k
    fi
  done
}


function switch-latex-to-tl-stable ()
{
  for i in "${tl_texbin_d}"/*-dev; do
    devname="$( basename "${i}")"
    stablename="${devname%-*}"
    # The file should contain just a shebang line and one line if it
    # is pointing to dev. Otherwise should be a link.
    if [ $(cat "${tl_texbin_d}/${stablename}" | wc -l) = "2" ]; then
      echo "${stablename} was calling dev."
      if [ ! -e "${tl_stable_bu_d}/${stablename}" ]; then
        echo "  restoring stable."
        sudo rm "${tl_texbin_d}/${stablename}"
        sudo cp -d "${tl_stable_bu_d}/${stablename}" "${tl_texbin_d}/${stablename}"

        \sudo -k
      else
        echo "ERROR: the stable backup file does not exist: ${tl_stable_bu_d}/${stablename}"
      fi
    else
      echo "${stablename} is already stable version."
    fi
  done
}


function switch-gcc-to ()
{
  sudo update-alternatives --set gcc "/usr/bin/gcc-$1"
  sudo update-alternatives --set g++ "/usr/bin/g++-$1"
  sudo update-alternatives --set gfortran "/usr/bin/gfortran-$1"

  \sudo -k
}
_switch_gcc_to()
{
  local cur

  cur=${COMP_WORDS[COMP_CWORD]}

  if [ "$COMP_CWORD" == "1" ]; then
    gcc_vers="$(ls /usr/bin/gcc-* | grep -o -P '(?<=gcc-)\d+(?=$)')"
    COMPREPLY=( $( compgen -W '${gcc_vers}' -- $cur ) )
  fi
}
complete -F _switch_gcc_to ${filenames:-} switch-gcc-to


function switch-clang-to ()
{
  sudo update-alternatives --set clang "/usr/bin/clang-$1"
  sudo update-alternatives --set clang++ "/usr/bin/clang++-$1"
  # I don't think Clang has a (built-in) fortran

  \sudo -k
}
_switch_clang_to()
{
  local cur

  cur=${COMP_WORDS[COMP_CWORD]}

  if [ "$COMP_CWORD" == "1" ]; then
    clang_vers="$(ls /usr/bin/clang-* | grep -o -P '(?<=clang-)\d+(?=$)')"
    COMPREPLY=( $( compgen -W '${clang_vers}' -- $cur ) )
  fi
}
complete -F _switch_clang_to ${filenames:-} switch-clang-to


function gcc-apt-get-install ()
{
  # todo: completion?

  # approximate size taken up by installing:
  # gcc:      ~423 MB
  # g++:      ~220 MB
  # gfortran: ~200 MB
  #
  sudo apt-get install \
  "gcc-$1" \
  "g++-$1" \
  "gfortran-$1"

  \sudo -k
}


function clang-apt-get-install ()
{
  # don't need to separately install "clang++-$1".
  # approximate size taken up by installing: # 722 MB
  sudo apt-get install "clang-$1"

  \sudo -k
}