#!/bin/bash
THIS=`basename $0`
COLUMNS=$(stty size 2>/dev/null||echo 80); COLUMNS=${COLUMNS##* }
while getopts ":qfh" optname; do
  case "$optname" in
    "f")	FORCE="y";;
    "q")	QUIET="y"; RDIFFBACKUPOPTIONS="--terminal-verbosity 0";;
    "h")	HELP="y";;
    "?")	echo "Unknown option $OPTARG"; exit 1;;
    ":")	echo "No argument value for option $OPTARG"; exit 1;;
    *)		# Should not occur
		echo "Unknown error while processing options"; exit 1;;
  esac
done
shift $(($OPTIND-1))
if [ -z "$QUIET" -o -n "$HELP" -o -z "$1" ]; then
	echo -en "\n$THIS v0.1216 by Dominic address@hidden"
	[ -z "$HELP" -a -n "$1" ] && echo -n " (-h for help)"
	echo -e "\n${THIS//?/=}\n"
fi
if [ -n "$HELP" -o -z "$1" ]; then
	echo -e "Forces regression of an rdiff-backup archive even if natural regression does not occur. Can be useful if a repository is corrupted and regression is neither automatic nor can be initiated with --check-destination-dir.\n\nUsage:  \t$THIS [options] archive-path\nExample: \t$THIS -f /home/fred/backup\nOptions:\tf - Force, proceed with no prompt\n\t\th - Help, this help text\n\t\tq - Quiet, no output unless error\n"|fold -s -w $COLUMNS
	exit
fi
if [ ! -d "$1" ]; then
	echo "Cannot find directory \"$1\", aborting..."
	exit 1
fi
ARCHIVE=$1
if [ ! -d "$ARCHIVE/rdiff-backup-data" ]; then
	echo "$ARCHIVE does not appear to be a valid rdiff-backup repository, aborting..."
	exit 1
fi
[ -z "$QUIET" ] && echo "Using repository: $ARCHIVE"
WHENLAST=`ls $ARCHIVE/rdiff-backup-data/current_mirror*|sed 's/.*current_mirror\.\([^.]*\).*/\1/'`
NUMCURRENT=`echo $WHENLAST|awk '{print NF}'`
if [ $NUMCURRENT -ne 2 ]; then
	if [ $NUMCURRENT -ne 1 ]; then
		echo "$NUMCURRENT current_mirror files, aborting..."
		exit 1
	else
		[ -z "$QUIET" ] && echo "rdiff-backup does not recognise this repository as damaged"
	fi
else
	[ -z "$QUIET" ] && echo "rdiff-backup recognises this repository as damaged"
fi
PREVRUN=`ls $ARCHIVE/rdiff-backup-data/mirror_metadata*|tail -n2|head -n1|sed 's/.*mirror_metadata\.\([^.]*\).*/\1/'`
if [ -z "$FORCE" ]; then
	read -n 1 -t 30 -p "About to regress $ARCHIVE repository from $WHENLAST to $PREVRUN: ok (y/-)? "
	[ "$REPLY" != "y" ] && echo " - aborting..." && exit 1
fi
[ -z "$QUIET" ] && echo -e "\nStarted `date`"
if [ $NUMCURRENT -eq 1 ]; then
	cp -a "$ARCHIVE/rdiff-backup-data/current_mirror.$WHENLAST.data" "$ARCHIVE/rdiff-backup-data/current_mirror.$PREVRUN.data"
	[ -z "$QUIET" ] && echo "Copied current_mirror"
fi
[ -z "$QUIET" ] && echo "Regressing, this may take a long time, please be patient..."
rdiff-backup $RDIFFBACKUPOPTIONS --check-destination-dir $ARCHIVE
[ -z "$QUIET" ] && echo "Ended `date`"
[ -z "$QUIET" ] && [ $? -eq 0 ] && echo "Regression completed successfully, current mirror is now $PREVRUN" || echo "There was an error while attempting to regress repository..."
REQOWNER=`ls -dl "$ARCHIVE/rdiff-backup-data/increments"|awk '{print $3":"$4}'`
THISOWNER=`ls -l "$ARCHIVE/rdiff-backup-data/mirror_metadata.$PREVRUN.snapshot.gz"|awk '{print $3":"$4}'`
if [ "$THISOWNERS" != "$REQOWNER" ]; then
	chown $REQOWNER "$ARCHIVE/rdiff-backup-data/mirror_metadata.$PREVRUN.snapshot.gz"
	chown $REQOWNER "$ARCHIVE/rdiff-backup-data/current_mirror.$PREVRUN.data"
fi