#!/bin/sh
set -e

# Copyright (C) 2006,2007,2008,2009,2010  Free Software Foundation, Inc.
#
# GRUB is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# GRUB is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with GRUB.  If not, see <http://www.gnu.org/licenses/>.

grub_mkconfig="/usr/sbin/grub2-mkconfig"
grub_mkrelpath="/usr/bin/grub2-mkrelpath"
grub_setting="/etc/default/grub"
grub_cfg="/boot/grub2/grub.cfg"
grub_snapshot_cfg="/boot/grub2/snapshot_submenu.cfg"

snapshot_submenu_name="snapshot_submenu.cfg"
snapshot_menuentry_name="snapshot_menuentry.cfg"
snapshot_menuentry_cfg="boot/grub2/${snapshot_menuentry_name}"

rel_root=`"$grub_mkrelpath" /`

snapshot_submenu_refresh () {

for s_dir in /.snapshots/*; do

  snapshot="${s_dir}/snapshot"
  snapper_cfg="${s_dir}/${snapshot_submenu_name}"
  
  if [ ! -d "$snapshot" ]; then
    rm -f "${snapper_cfg}"
    rm -f "${s_dir}/${snapshot_menuentry_name}"
    continue
  fi

  cfgs="${s_dir}/${snapshot_menuentry_name} ${snapshot}/${snapshot_menuentry_cfg}"
  date=`xmllint --xpath '/snapshot/date/text()' "${s_dir}/info.xml" || echo ""`

  cat <<EOF > "${snapper_cfg}.new"
  
  for x in $cfgs; do
    snap="${rel_root}${snapshot}"
    snap_cfg="${rel_root}\$x"

    if [ -f "\$snap_cfg" ]; then
      snapshot_found=true
	submenu "$date" "\$snap" "\$snap_cfg" {
		set subvol="\$2"
		export subvol
		source "\$3"
	}
      break
    fi
  done

EOF
 
  if grub2-script-check "${snapper_cfg}.new"; then
    mv -f "${snapper_cfg}.new" "${snapper_cfg}"
  fi

done

}

grub_snapshot_cfg_refresh () {

: > "${grub_snapshot_cfg}.tmp"
for s_dir in /.snapshots/*; do

  snapshot="${s_dir}/snapshot"
  snapper_cfg="${s_dir}/${snapshot_submenu_name}"

  if [ -f "${snapper_cfg}" ]; then
    echo "source ${rel_root}${snapper_cfg}" >>"${grub_snapshot_cfg}.tmp"
    continue
  fi

done

cat <<EOF >"${grub_snapshot_cfg}.new"
submenu "Bootable snapshots" { 
`sort -V "${grub_snapshot_cfg}.tmp"` 
  if [ x\$snapshot_found != xtrue ]; then
	submenu "Not Found" {true}
  fi
}
EOF

if grub2-script-check "${grub_snapshot_cfg}.new"; then
  mv -f "${grub_snapshot_cfg}.new" "${grub_snapshot_cfg}"
fi

}


snapshot_submenu_clean () {

  for s_dir in /.snapshots/*; do

    snapshot="${s_dir}/snapshot"
    snapper_cfg="${s_dir}/${snapshot_submenu_name}"

    if [ -f "$snapper_cfg" ]; then
      rm -f "$snapper_cfg"
    fi

  done
}

set_grub_setting () {

  name=$1
  val=$2

  if grep -q "$name" "$grub_setting"; then
    sed -i -e "s/.*\($name\)=.*/\1=$val/" "$grub_setting"
  else
    echo "$name=$val" >> "$grub_setting"
  fi
}

update_grub_cfg () {

  "$grub_mkconfig" -o "$grub_cfg"
}

# Check the arguments.
while test $# -gt 0
do
  option=$1
  shift

  case "$option" in
  -e | --enable)
  opt_enable=true
  ;;
  -d | --disable)
  opt_enable=false
  ;;
  -r | --refresh)
  opt_refresh=true
  ;;
  -c | --clean)
  opt_clean=true
  ;;
  -*)
  ;;
  esac
done

if [ "x${opt_enable}" = "xtrue" ]; then

  set_grub_setting SUSE_DISABLE_BOOTING_SNAPSHOT false
  set_grub_setting SUSE_ENABLE_CUSTOM_SNAPSHOT_SUBMENU true
  update_grub_cfg
  snapshot_submenu_refresh
  grub_snapshot_cfg_refresh

elif [ "x${opt_enable}" = "xfalse" ]; then

  snapshot_submenu_clean
  set_grub_setting SUSE_DISABLE_BOOTING_SNAPSHOT true
  set_grub_setting SUSE_ENABLE_CUSTOM_SNAPSHOT_SUBMENU false 
  update_grub_cfg

fi

if [ x${opt_refresh} = "xtrue" ]; then

  snapshot_submenu_refresh
  grub_snapshot_cfg_refresh

fi

if [ x${opt_clean} = "xtrue" ]; then

  snapshot_submenu_clean
  grub_snapshot_cfg_refresh

fi