#!/bin/bash -
USAGE="Usage: $0 [-v] [ -k keyfile | -y keyname:secret] domainname"
TEMP=`getopt -o k:y:v -n 'dnsvi' -- "$@"`

if [ $? != 0 ] ; then echo $USAGE >&2 ; exit 1 ; fi

eval set -- "$TEMP"
NSUARGS=""

while true ; do
	case "$1" in
		-k)
			NSUARGS="-k $2"
			shift 2
			;;
		-y)
			NSUARGS="-y $2"
			shift 2
			;;
		-v)
			NSUARGS="-v"
			shift
			;;
		--)
			shift
			break
			;;
	esac
done

if [ $# -ne 1 ]
then
	echo $USAGE >&2
	exit 1
fi

DOMAIN="$(echo $1 | sed -e 's/\.$//g' )"


ORIG=`mktemp -t dnsvi.XXXXXX`
NEW=`mktemp -t dnsvi.XXXXXX`
DIFF=`mktemp -t dnsvi.XXXXXX`

trap "rm -f $ORIG $NEW $DIFF" EXIT SIGTERM SIGINT

[ -z "$EDITOR" ] && export EDITOR=vi

DNSSORT='{ split ($1, fragments, "."); name=""; for (fragment in fragments) name=fragments[fragment](name?"." name:"") ; printf name; for (i = 2; i <= NF; i++) printf OFS $i; printf ORS; delete fragments }'

dig -t axfr $DOMAIN | sed -e  '/^;/d;s/@/\\@/g;/^[ \t]*$/d;s/'$(echo $DOMAIN | sed -e 's/\./\\./g' )'\.\([ \t]\)/@\1/g;s/'$(echo $DOMAIN | sed -e 's/\./\\./g' )'\.$/@/g' | awk "${DNSSORT}" | sort | uniq | awk "${DNSSORT}" > $ORIG

if [ $(wc -l $ORIG | cut -f 1 -d " ") -eq 0 ]
then
	echo I got nothing when looking for $DOMAIN. I give up.
	exit 1
fi

cat $ORIG > $NEW

$EDITOR $NEW

diff --unchanged-line-format="" --new-line-format="update add %L" --old-line-format="update delete %L" -bB $ORIG $NEW | sed -e 's/\\@/@/g;s/@/'$DOMAIN'./g'  > $DIFF

if [ $(wc -l $DIFF | cut -f 1 -d " ") -gt 0 ]
then
	echo In zone $DOMAIN
	echo
	cat $DIFF 
	echo
	echo 'Press enter to do it or ^C to abort.'
	read
	( echo zone $DOMAIN ; cat $DIFF ; echo send)  | nsupdate $NSUARGS
else
	echo No changes found.
fi
exit 0