#!/bin/bash
#
# Name: ddnsedit
# Description: Edit a dynamic dns zone with an editor, then update it by
# calling "nsupdate"
#
# Copyright (C) 2008  Emmanuel Lacour <elacour@home-dn.net>
# 
#  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.



SERVER=$1
ZONE=$2


function usage {
    echo "Usage: `basename $0` SERVER ZONE_NAME"
    exit 0
}

if [ ! -n "$ZONE" ]
then
    echo "Missing zone name!"
    usage
fi

if [ ! -n "$SERVER" ]
then
    echo "Missing server!"
    usage
fi


# Cleanup zone name
if [ `echo "$ZONE" | grep -c '\.$'` -eq 0 ]
then
    ZONE="$ZONE."
fi

FILE_O=`mktemp /tmp/nsedit_o.XXXXXX`
FILE_N=`mktemp /tmp/nsedit_n.XXXXXX`
FILE_D=`mktemp /tmp/nsedit_d.XXXXXX`
FILE_U=`mktemp /tmp/nsedit_u.XXXXXX`
FILE_ERR=`mktemp /tmp/nsedit_err.XXXXXX`

# Get the current zone
# (skip SOA wich cannot be updated by nsupdate)
dig @$SERVER $ZONE AXFR | grep -Ev '^;|^$' | grep -v 'IN	SOA	' > $FILE_O

# Duplicate the zone
cat $FILE_O > $FILE_N

function main {
    # Edit the zone
    $EDITOR $FILE_N

    # Diff between old and new file
    diff -au $FILE_O $FILE_N | grep -E '^-|^\+' | grep -Ev '^--- |^\+\+\+ ' > $FILE_D

    if [ ! -s $FILE_D ]
    then
        echo "Empty changes, exiting!"
        exit 0
    fi

    # Prepare nsupdate file
    echo "server $SERVER" > $FILE_U
    # Diff between zones
    sed 's/^-/update delete /g;s/^+/update add /g' $FILE_D >> $FILE_U
    echo 'send' >> $FILE_U

    echo "Do you really wan't to send the following updates?"
    cat $FILE_U
    echo -n "Answer (y/n):"
    read a

    if [ "$a" == "y" ]
    then
        nsupdate $FILE_U > $FILE_ERR 2>&1
        if [ $? -ne 0 ]
        then
            echo "Update failed: "
            cat $FILE_ERR
            echo -n "Do you wan't to edit back you're file (y/n): "
            read a
            if [ "$a" == "y" ]
            then
                main
            else
                echo "Ok, exiting..."
            fi
        else
            echo "Update succeded!"
            cat $FILE_ERR
        fi
    else
        echo "Ok, exiting..."
    fi
}

main

rm -f $FILE_O $FILE_N $FILE_D $FILE_U $FILE_ERR