#!/usr/bin/env zsh

scriptname=${0##*/}

usage() {
	cat <<EOF
usage: $scriptname [mac] [ip]

$scriptname assign ip to specified mac-address
EOF
}
if [[ -z $1 ]]; then
	usage
	exit 0
fi

zmodload zsh/mapfile

dhosts_name=/etc/dnsmasq-dhcp_hosts.conf
dhosts=$mapfile[$dhosts_name]

valid_mac="^([[:xdigit:]][[:xdigit:]]:?){6}$"

if ! [[ $1 =~ $valid_mac ]] ; then
	print >&2 "Invalid mac address.\n"
	exit 1
fi

if print $dhosts | grep -q $1; then
	printf >&2 "An entry with MAC-address %s already exists.\n" $1
	exit 1
fi

if print $dhosts | grep -q $2; then
	printf >&2 "An entry with IP-address %s already exist.\n" $2
	exit 1
fi

print "$1,$2" >> $dhosts_name
pkill -x -HUP dnsmasq