#!/bin/sh

# Copyright (c) 2013 Stefan Huber <shuber@sthu.org>
#
# Permission is hereby granted, free of charge, to any person
# obtaining a copy of this software and associated documentation
# files (the "Software"), to deal in the Software without
# restriction, including without limitation the rights to use,
# copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the
# Software is furnished to do so, subject to the following
# conditions:
#
# The above copyright notice and this permission notice shall be
# included in all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
# OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
# HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
# WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
# FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
# OTHER DEALINGS IN THE SOFTWARE.

set -e

PROGNAME=$(basename $0)

usage() {
    cat <<EOF
Increments serial in zonefile by one.

Usage: $PROGNAME zonefile [OPTIONS]

Options:
    -h, --help      Print this text.
EOF
}

TEMP=`getopt -o "h" --long "help" -n "$PROGNAME" -- "$@"`
eval set - "$TEMP"

while true; do
    case "$1" in
        -h | --help )
            usage
            exit $STATE_OK ;;
        -- )
            shift
            break ;;
        * )
            break ;;
    esac
done

if [ "$#" = "0" ]; then
    echo "Not enough arguments."
    usage
    exit 1
fi

zonefile=$1
if ! [ -r "${zonefile}" ]; then
    echo "Zone file does not exist: '${zonefile}'"
    exit 2
fi

getSerialFromZonefile() # <zonefile>
{
	awk '/; serial/{print$1}' "$1"
}

setSerialInZonefile() # <zonefile> <serial>
{
	sed -i -e "s_^\\(.*\\s\\)[0-9]\+\\(\\s\\+; serial.*\\)_\\1$2\\2_g" "$1"
}


serial=`getSerialFromZonefile "${zonefile}"`
serial=$(( $serial + 1))

if [ -z "$serial" ]; then
    echo "Internal error, serial is empty."
    exit 1
fi

setSerialInZonefile "${zonefile}" "${serial}"