#!/bin/bash

function lookup() {  # lookup where_var res_var what to lookup ...
	local all what found rv localres where_var res_var
	where_var="$1" ; shift
	res_var="$1" ; shift
	all="${*}"
	what=${all// /|}
	found=""
	localres=$(egrep -i "$what" $SRVFILE_CUSTOM)
	if [[ ! -z $localres ]]; then
		found="custom"
        else
		localres=$(egrep -i "$what" $SRVFILE_BASE)
		[[ ! -z $localres ]] && found="system"
	fi
	eval "$where_var=${found}"
	eval "$res_var='${localres}'"
	if [[ -z $found ]]; then
		rv=1
	else
		rv=0
	fi
	return $rv
	echo "$found"
}

function usage() {
	echo "usage:  $0 [OPTIONS] command [command_args]"
	echo
	echo "Manage custom /etc/services entries."
	echo
	echo "  Valid commands are:   $VALIDMODES"
	echo
	echo "   -f   Force removal of service even if multiple match."
	echo "   -w   Update system services file ($SRVFILE_ACTIVE)" 
	echo "   -y   Same as -w"
	echo
}

function getalt() {
	local newmode
	newmode="$1"
	case $1 in
		a)
			newmode="add";
			;;
		q)
			newmode="query";
			;;
		rm)
			newmode="del";
			;;
	esac
	echo "$newmode"

}

function makeboth() {
	local n p both
	n="$1"
	p="$2"
	both="$n"
	if [[ ! -z $p ]]; then
		if [[ ! -z $n ]]; then
			both="$both ("
		fi
		both="$both$p"
		if [[ ! -z $n ]]; then
			both="$both)"
		fi
	fi
	echo "$both"
}

function stageforsync() {
	cp -fp "$SRVFILE_BASE" "$SRVFILE_STAGE"
	echo >> "$SRVFILE_STAGE"
	echo "# custom services from serv.sh" >> "$SRVFILE_STAGE"
	cat "$SRVFILE_CUSTOM" >> "$SRVFILE_STAGE"
}

function synctoactive() {
	local perm dres 

	stageforsync
	dres=$(diff "$SRVFILE_ACTIVE" "$SRVFILE_STAGE")

	echo
	if [[ $DOIT -eq 1 ]]; then
		perm=$(stat -f "%p" "$SRVFILE_ACTIVE")
		if [[ $UID -ne 0 && $EUID -ne 0 ]]; then
			echo "(using sudo - you may be prompted for your password)"
			sudo cp -fp "$SRVFILE_ACTIVE" "$SRVFILE_ACTIVE.orig"
			sudo cp -fp "$SRVFILE_STAGE" "$SRVFILE_ACTIVE"
			sudo chmod $perm "$SRVFILE_ACTIVE"
		else
			cp -fp "$SRVFILE_ACTIVE" "$SRVFILE_ACTIVE.orig"
			cp -fp "$SRVFILE_STAGE" "$SRVFILE_ACTIVE"
			chmod $perm "$SRVFILE_ACTIVE"
		fi

		if [[ -z $dres ]]; then
			echo "No changes required to $SRVFILE_ACTIVE."
		else
			echo "$SRVFILE_ACTIVE updated:"
			echo "$dres" | sed -e 's/^/   /'
		fi
	else
		echo "NOTE: $SRVFILE_ACTIVE not touched - use -w to update it."
		echo "The following changes were NOT made:"
		if [[ -z $dres ]]; then
			echo "   (none)"
		else
			echo "$dres" | sed -e 's/^/   /'
		fi
	fi
}

# Handle args
VALIDPROTOS="tcp udp"
VALIDMODES="diff sync init add del query cat"
MODE=""
SRVFILE_ACTIVE="/etc/services"
SRVDIR="${HOME}/.serv"
SRVFILE_BASE="${SRVDIR}/base"
SRVFILE_CUSTOM="${SRVDIR}/custom"
SRVFILE_STAGE="${SRVDIR}/stage"
PROTOFILE=/etc/protocols
FORCE=0
DOIT=0

ARGS="fhwy"
while getopts "$ARGS" i; do
	case "$i" in
		f)
			FORCE=1
			;;
		h)
			usage;
                        exit 1
			;;
		w)
			DOIT=1;
			;;
		y)
			DOIT=1;
			;;
		*)
			echo "ERROR: invalid argument:  $i";
			usage;
			;;
	esac
done
shift $((OPTIND - 1))

if [[ $# -eq 0 ]]; then
	echo "Error - no mode provided."
	usage
	exit 1
fi

MODE="$1"
shift 1
MODE=$(getalt $MODE)

if [[ $VALIDMODES != *$MODE* ]]; then
	echo "Error - invalid mode '$MODE'"
	echo "Valid modes are:   $VALIDMODES"
	exit 1
fi


if [[ $MODE == "cat" ]]; then
	echo "Current custom services (from $SRVFILE_CUSTOM):"
	cat "$SRVFILE_CUSTOM" | sed -e 's/^/   /'
	exit 0
elif [[ $MODE == "diff" ]]; then
	stageforsync
	dres=$(diff "$SRVFILE_ACTIVE" "$SRVFILE_STAGE")
	echo "Changes to be synced into $SRVFILE_ACTIVE:"
	if [[ -z $dres ]]; then
		echo "   (none)"
	else
		echo "$dres" | sed -e 's/^/   /'
	fi
	exit 0
elif [[ $MODE == "sync" ]]; then
	# just update /etc/services
	synctoactive
	exit 0
elif [[ $MODE == "init" ]]; then
	wantargs=0
elif [[ $MODE == "add" ]]; then
	wantargs=2
else
	wantargs=1
fi

if [[ $# -lt $wantargs ]]; then
	echo "Bad arguments - want $wantargs, got $#"
	echo
	usage
	exit 1
fi

name="$1"
protoport="$2"
if [[ -z $protoport ]]; then
	proto=""
	port=""
else
	if [[ $protoport != */* ]]; then
		echo "Error - bad service specification '$protoport'"
		echo "Must use the format:   port/protocol"
		exit 1
	fi
	proto="${protoport#*/}"
	port="${protoport%/*}"
	re='^[0-9]+$'
	if [[ ! $port =~ $re ]]; then
		echo "Error - port '$port' is not a number."
		echo "Must use the format:   port/protocol"
		exit 1
	fi
	if [[ $port -lt 0 || $port -gt 65535 ]]; then
		echo "Error - port '$port' must be in the range 0-65535."
		exit 1
	fi
	if [[ $VALIDPROTOS != *$proto* ]]; then
		echo "Error - invalid protocol '$proto'."
		echo "Valid protocols are:  $VALIDPROTOS"
		exit 1
	fi
	shift 2
	comment="$*"
fi
both=$(makeboth $name $protoport)

if [[ $MODE == "init" ]]; then
	if [[ -d $SRVDIR ]]; then
		echo "error -i $SRVDIR already exists."
		exit 1
	fi
	mkdir -p "$SRVDIR"
	cp -p "$SRVFILE_ACTIVE" "$SRVFILE_BASE"
	cp /dev/null "$SRVFILE_CUSTOM"
	echo "Initialisation of $SRVDIR complete."
	exit 0
elif [[ ! -d $SRVDIR ]]; then
	echo "Error - $SRVDIR is missing."
	echo "Use -i to initialise it."
	exit 1
fi


if [[ $MODE == "query" ]]; then
	lookup whichfile res $name $protoport
	if [[ ! -z $whichfile ]]; then
		echo "Found in $whichfile services file:"
		echo "$res" | sed -e 's/^/   /'
		exit 0
	else
		echo "'$both' not found."
		exit 1
	fi
elif [[ $MODE == "add" ]]; then
	lookup whichfile res $name $protoport
	if [[ ! -z $whichfile ]]; then
		echo "Error - this already exists in $whichfile services file:"
		echo "$res" | sed -e 's/^/   /'
		exit 1
	fi
	if [[ ${#name} -gt 15 ]]; then
		echo "Error - service name '$name' exceeds 15 characters."
		exit 1
	fi
	if [[ -z $comment ]]; then
		printf "%-16s%s\n" "$name" "$protoport" >> $SRVFILE_CUSTOM 
	else
		printf "%-16s%s # %s\n" "$name" "$protoport" "$comment" >> $SRVFILE_CUSTOM 
	fi
	echo "Added '$name' ($protoport) to custom services file."
	synctoactive
elif [[ $MODE == "del" ]]; then
	lookup whichfile res $name $protoport
	if [[ $whichfile != "custom"  ]]; then
		echo "Error - can't find service '$both' in custom file."
		exit 1
	fi
	re="$name"
	if [[ ! -z $protoport ]]; then
		if [[ ! -z $re ]]; then
			re="$re|"
		fi
		re="$re${protoport}"
	fi
	re="${re/\//\\\/}" # escape the slash
	count=$(egrep -c "$re" $SRVFILE_CUSTOM)
	[[ $count -eq 1 ]] && ess="" || ess="s"
	if [[ $count -gt 1 && $FORCE -ne 1 ]]; then
		echo "Error:  '$both' matches multiple lines for removal, use -f to confirm:"
		echo "$res" | sed -e 's/^/   /'
		exit 1
	fi
	sed -ibak "/$re/d" $SRVFILE_CUSTOM
	sedrv=$?
	if [[ $sedrv -eq 0 ]]; then
		echo "Removed '$both' from custom services file ($count line$ess)."
		rv=0
	else
		echo "Error failed to remove '$both' from custom services file using sed."
		rv=1
	fi
	synctoactive
	exit $rv
fi

	# TODO: sync to real serviceafile
exit 0