#!/bin/bash
# This script is meant to be called automatically by dnsmasq's dhcp-script directive 
# but it can also be used to manage the manual insertion and deletion of nodes. 
# Make sure dnsmasq doesn't come an play against you though.

%%MODULESPATH
BEEPS=%%BEEPS

run_modules(){
	for I in ${MODULESPATH}/*-${COMMAND}
	do
		$I $@
	done
	eval \$BEEP_$COMMAND
}

# Yes, it's crude but we'll elaborate later on something more functionnal
# ...say something based on Avahi with live beakons
node_is_alive(){
	ping -c 1 -w 1 $HNAME
	return $?
}

# Nodes can either be added or removed. For a thorough description of the mechanism, see
# dnsmasq's manpage section concerning dhcp-script
old_node(){
	if [[ ! node_is_alive  ]]; then
		shift
		$0 del $*
	fi
}

usage(){
	echo "$0 is called as follows:"
	echo "$0 <add|del|old> <MAC address> <IP address> <hostname>"
}

(( $# != 3 )) && { usage; exit 1 };

##### Variables #######
COMMAND=$1
MACADDR=$2
IP=$3
HNAME=$4

### Beeps:
PAUSE=20
START=200
STOP=2000
STEP=200
BEEP_add="$(for I in `seq $START $STEP $STOP`; do echo -n " -f $I -l $PAUSE -r 1 -n"; done)"
BEEP_del="$(for I in `seq $STOP -$STEP $START`; do echo -n " -f $I -l $PAUSE -r 1 -n"; done)"
BEEP_add="beep ${BEEPS_add%%-n}"
BEEP_del="beep ${BEEPS_del%%-n}"

##### Variables END ###

if [[ $COMMAND == "old" ]]
then
	old_node $@
else
	run_modules $@
fi

exit 0