_bs_user=bs
_bs_group=bs

post_install() {
  _mkuser
  # disable Copy-On-Write (btrfs directories only)
  for _dir in /srv/bs /var/log/bs; do
    _is_btrfs "$_dir" && _disable_cow "$_dir"
  done
  chown -R $_bs_user:$_bs_group /etc/bs /srv/bs /var/log/bs
  printf "%b\n" "$obelisk"
}

post_upgrade() {
  _mkuser
  chown -R $_bs_user:$_bs_group /etc/bs /srv/bs /var/log/bs
  printf "%b\n" "$obelisk"
}

post_remove() {
  _rmuser
  rm -rf /etc/bs /srv/bs /var/log/bs
}


# ------------------------------------------------------------------------------
# helper functions for creating libbitcoin-server user / group
# ------------------------------------------------------------------------------

_mkuser() {
  getent passwd $_bs_user &>/dev/null || {
    echo -n "Creating libbitcoin-server user... "
    grep -E "^$_bs_group:" /etc/group >/dev/null || groupadd $_bs_group
    useradd -m -d /etc/bs -g $_bs_group -s /usr/bin/nologin $_bs_user
    echo "done"
  }
}

_rmuser() {
  echo -n "Removing libbitcoin-server user... "
  userdel -rf $_bs_user 2>/dev/null
  echo "done"
}


# ------------------------------------------------------------------------------
# helper functions for disabling btrfs Copy-On-Write (CoW)
# https://wiki.archlinux.org/index.php/Btrfs#Copy-On-Write_.28CoW.29
# ------------------------------------------------------------------------------

# check if dir is btrfs
_is_btrfs() {
  if [[ $(findmnt --target $1 --output FSTYPE --noheadings) == 'btrfs' ]]; then
    return 0
  else
    return 1
  fi
}

# disable btrfs CoW
_chattrify() {
  # original dir, with trailing slash stripped if it exists
  _orig_dir=$( echo "$1" | sed 's@/$@@' )

  # if original dir exists, back it up
  [[ -d "$1" ]] && mv "$1" "${_orig_dir}"_old

  # re-make original dir
  mkdir -p "$1"

  # set permissions on re-made dir
  chmod "$2" "$1"

  # disable btrfs CoW on re-made dir
  chattr +C "$1"

  # recursive copy to restore backed up dir while maintaining disabled CoW
  [[ -d "${_orig_dir}"_old ]] \
    && find "${_orig_dir}"_old -mindepth 1 -maxdepth 1 -exec cp -R '{}' "$1" \;

  # set ownership on re-made dir
  chown -R $3:$4 "$1"

  # purge backed up dir
  [[ -d "${_orig_dir}"_old ]] && rm -rf "${_orig_dir}"_old
}

_disable_cow() {
  _chattrify "$1" "755" "$_bs_user" "$_bs_group"
}


read -d '' obelisk <<'EOF'
########################################################################
########################################################################
##                                                                    ##
##  Libbitcoin Server                                                 ##
##  _________________                                                 ##
##                                                                    ##
##  To run:                                                           ##
##                                                                    ##
##      systemctl start bsinit # first run only                       ##
##      systemctl start bs                                            ##
##                                                                    ##
##                                                                    ##
##  Config:        /etc/bs/bs.cfg                                     ##
##  Blockchain:    /srv/bs                                            ##
##  Documentation: /usr/share/doc/libbitcoin-server                   ##
##  Logs:          /var/log/bs                                        ##
##                                                                    ##
########################################################################
########################################################################
EOF