#!/bin/sh

# Configuration
DIR_SOURCE=""
DIR_DESTINATION=""
MAX_WAIT=60
RSYNC_OPTIONS="-q -aH --delete"
INOTIFYWAIT_OPTIONS="-qq -r -e close_write -e attrib -e move -e create -e delete -e unmount"
#RSYNC_OPTIONS="-v -aH --delete"
#INOTIFYWAIT_OPTIONS="-r -e close_write -e attrib -e move -e create -e delete -e unmount"

# On essaie de diminuer la priorité de la chose
# Aucune importance si les utilitaires ne sont pas dispos
renice 15 -p $$ >/dev/null 2>&1
ionice -c 3 -p $$ >/dev/null 2>&1

# Arrêt à la moindre erreur non-catchée
set -e

# Fonctions
# Little helper to centralize syslog calls
loglog() {
	LEVEL="$1"
	shift
	logger -s -t inotify-rsync -p user.$LEVEL $@
}

# affiche le message d'aide
usage() {
cat <<EOF
  $0 [-i inotifywait_options] [-r rsync_options] [-t max_wait] -s source_directory -d rsync_destination
  $0 -h

	-s :	specify the rsync source (needs to be a local directory)
	-d :	specify the rsync destination (can be anythin rsync accepts)
	-i :	inotifywait options (minus the -t option)
			(default : "$INOTIFYWAIT_OPTIONS")
	-r :	rsync options
			(default : "$RSYNC_OPTIONS")
	-t :	Even without event (or in case of missed event), rsync will be launched every "max_wait" seconds
			(0 = wait forever)  (default: $MAX_WAIT)

	-h :	this help screen
EOF
}

# Début du code
# gestion des options de lancement
while getopts s:d:r:w:h o; do
	case $o in
		's')
			DIR_SOURCE="$OPTARG"
			;;

		'd')
			DIR_DESTINATION="$OPTARG"
			;;

		'i')
			INOTIFYWAIT_OPTIONS="$OPTARG"
			;;

		'r')
			RSYNC_OPTIONS="$OPTARG"
			;;

		'w')
			MAX_WAIT="$OPTARG"
			;;

		'h')
			usage
			exit 0
			;;

		\?)
			usage >&2
			exit 1
			;;
	esac
done
#shift $( expr $OPTIND - 1 )
#REPDRUPAL="$1"

# Some checks
if [ -z "$DIR_SOURCE" ] || [ ! -d "$DIR_SOURCE" ]; then
	loglog err "ERROR: no source specified or directory inexistent." >&2
	exit 1
fi
if [ -z "$DIR_DESTINATION" ]; then
	loglog err "ERROR: no destination specified." >&2
	exit 1
fi

while true; do
	# rsync can send error code != 0, we'll have to check
	# what this code means before failing
	set +e
	rsync $RSYNC_OPTIONS "$DIR_SOURCE" "$DIR_DESTINATION"
	RSYNC_RETURN_CODE="$?"
	set -e
	while [ "$RSYNC_RETURN_CODE" -ne "0" ]; do
		for i in 24; do
			if [ "$RSYNC_RETURN_CODE" -eq "$i" ]; then
				# If the return code is "acceptable", we go on
				loglog debug "DEBUG: rsync returned code '$RSYNC_RETURN_CODE'"
				break 2
			fi
		done
		# The return code wasn't in the "acceptable" list => log + exit
		loglog err "ERROR: rsync returned unexpected error code : $RSYNC_RETURN_CODE. Script stopped."
		exit $RSYNC_RETURN_CODE
	done

	# Wait for another change
	# inotifywait can send error code != 0, we'll have to check
	# what this code means before failing
	set +e
	inotifywait $INOTIFYWAIT_OPTIONS -t "$MAX_WAIT" "$DIR_SOURCE"
	INOTIFYWAIT_RETURN_CODE="$?"
	set -e
	if [ "$INOTIFYWAIT_RETURN_CODE" -ne "0" ]; then
		if [ "$INOTIFYWAIT_RETURN_CODE" -ne "2" ]; then
			loglog err "ERROR: inotifywait returned unexpected error code : $INOTIFYWAIT_RETURN_CODE. Script stopped."
			exit $INOTIFYWAIT_RETURN_CODE
		fi
	fi
done