#!/bin/bash
# -------
# File:        lliurex-dmrc
# Description: LliureX /etc/skel/.dmrc manager
# Author:      Luis Garcia Gisbert <garcia_luigis@gva.es>
# 
# This program 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 2 of the License, or
# (at your option) any later version.
#
# This program 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 this program; if not, write to the Free Software Foundation, Inc., 
# 51 Franklin St, Fifth Floor, Boston MA 02110-1301 USA
# --------

set -e

PATH="/usr/sbin:/usr/bin:/sbin:/bin"

TARGET_FILE="/etc/skel/.dmrc"
TEMPLATE_FILE="/usr/share/lliurex-base-files/skel/.dmrc"
REG_EXP="^\([[:alnum:]_]\+\)/\([[:alnum:]_]\+\)=\([-[:alnum:]_]\+\)$"
REG_EXP_NOVALUE="^\([[:alnum:]_]\+\)/\([[:alnum:]_]\+\)$"
# functions
usage() {
  VERBOSE="Y"
  CMD_NAME="$(basename "$0")"
  echo "Usage: $CMD_NAME {create|remove}" >&2
  echo "       $CMD_NAME add SECTION/VAR=VALUE" >&2
  echo "       $CMD_NAME del SECTION/VAR" >&2
  exit 1
}

create_target(){
   [ -w "$TARGET_FILE" ] || cat "$TEMPLATE_FILE" |install_target
   return 0
}

install_target(){
   mkdir -p "$(dirname "$TARGET_FILE")"
   TMP_FILE="$(tempfile)"
   cat - > "$TMP_FILE"
   chmod 644 "$TMP_FILE"
   mv -f "$TMP_FILE" "$TARGET_FILE"
}

change_var(){
   SEC_NAME="$1"
   VAR_NAME="$2"
   VAR_VALUE="$3"
   sed -e "/^\[$SEC_NAME\]/,/^\[/{/^$VAR_NAME=/s%=.*$%=$VAR_VALUE%}" "$TARGET_FILE"
}

add_var(){
   SEC_NAME="$1"
   VAR_NAME="$2"
   VAR_VALUE="$3"
   sed -e "/^\[$SEC_NAME\]/a$VAR_NAME=$VAR_VALUE" "$TARGET_FILE"
}

del_var(){
   SEC_NAME="$1"
   VAR_NAME="$2"
   sed -e "/^\[$SEC_NAME\]/,/^\[/{/^$VAR_NAME=/d}" "$TARGET_FILE"
}

add_section(){
   SEC_NAME="$1"
   sed -e "\$a[$SEC_NAME]" "$TARGET_FILE" 
}

test_section(){
   SEC_NAME="$1"
   grep -q "^\[$SEC_NAME\]" "$TARGET_FILE" || return 1
   return 0
}

test_var(){
   SEC_NAME="$1"
   VAR_NAME="$2"
   sed -ne "/^\[$SEC_NAME\]/,/^\[/p" "$TARGET_FILE" |grep -q "^$VAR_NAME=" "$TARGET_FILE" || return 1
   return 0
}

# ----
# main
# ----

ACTION="$1"
[ "$ACTION" ] || usage
echo " add del create remove " |grep -q " $ACTION " || usage
shift
case "$ACTION" in
   add)
      echo "$1" |grep -q "$REG_EXP" || usage
      SEC_NAME="$(echo "$1" |sed -ne "s%$REG_EXP%\1%p")"
      VAR_NAME="$(echo "$1" |sed -ne "s%$REG_EXP%\2%p")"
      VAR_VALUE="$(echo "$1" |sed -ne "s%$REG_EXP%\3%p")"
      [ "$SEC_NAME"  -a "$VAR_NAME" -a "$VAR_VALUE" ] || usage
      create_target
      test_section "$SEC_NAME" || add_section "$SEC_NAME" |install_target
      if ! test_var "$SEC_NAME" "$VAR_NAME" ; then
         add_var "$SEC_NAME" "$VAR_NAME"  "$VAR_VALUE" |install_target
      else
         change_var "$SEC_NAME" "$VAR_NAME"  "$VAR_VALUE" |install_target
      fi
      ;;
   create)
      create_target
      ;;
   remove)
      rm -f "$TARGET_FILE"
      ;;
   del)
      echo "$1" |grep -q "$REG_EXP_NOVALUE" || usage
      SEC_NAME="$(echo "$1" |sed -ne "s%$REG_EXP_NOVALUE%\1%p")"
      VAR_NAME="$(echo "$1" |sed -ne "s%$REG_EXP_NOVALUE%\2%p")"
      if test_section "$SEC_NAME" ; then
         del_var "$SEC_NAME" "$VAR_NAME" |install_target
      fi
      ;;
   esac
exit 0