#! /bin/sh
# patchview, Copyright (C) 2005 Randy Dunlap <rdunlap@xenotime.net>
# License:  GPL v2.
#
# uses patchutils (lsdiff) and tkdiff

PROG=patchview
VERSION=002

# usage: help message and exit
function usage()
{
	echo "usage: $PROG [-f] patchfile srctree {ver. $VERSION}"
	echo "  -f : force tkdiff even if 'patch' has errors"
	echo "  -s : single tkdiff even if patchfile contains multiple files"
	exit 1
}

# strip_filename:
# input: filename being patched
# returns 'base', which is directory level(s) (path) without filename
function strip_filename()
{
	fn=$1
	len=${#fn}
	fx=$((len - 1))
	base=""
	while [ 1 -eq 1 ]; do
		if [ ${fn:$fx:1} == "/" ]; then
			##fx=$((fx - 1))
			base=${fn:0:$fx}
			break
		fi
		fx=$((fx - 1))
		if [ $fx -eq 0 ]; then
			break
		fi
	done
}

force=0
single=0
VIEWER="tkdiff"
# or maybe "sh -c colordiff" would work

while [ -n "$1" ]
do
	case $1 in
	-f)
		force=1
	;;

	-s)
		single=1
	;;
    	-*)
		if [ "${1#-}" = '?' ]; then
			usage
		fi
	;;
	
    	*)
		# Accept filename or report a warning
		if [ -z "${patchfile}" ]; then
			patchfile=$1
			srctree=$2
			break
		else
			usage
		fi
	;;
    	esac

    	# Shift argument 2 into argument 1's slot.  Loop to check the argument.
    	shift
done

if [ "$patchfile" = "" -o "$srctree" = "" ]; then
	usage
fi

# setup temp working directory
if [ -d ~/tmp ]; then
	TMPDIR=~/tmp
else
	TMPDIR=/tmp
fi
if [ ! -d ${TMPDIR} ]; then
	mkdir ${TMPDIR} || echo "failed mktemp for patch files dir."
fi

WORKDIR=`mktemp -d -p ${TMPDIR} src.XXXXXX` || \
	{ echo "failed mktemp for patch files dir."; exit 1; }

pfiles=`lsdiff --strip 1 $patchfile`

for pf in $pfiles ; do
	strip_filename $pf	# sets 'base'
	##echo pf: $pf + basename: $base
	if [ "$base" != "" ]; then
		if [ ! -e $WORKDIR/$base ]; then
			mkdir -p $WORKDIR/$base
		fi
	fi
	if [ -e $srctree/$pf ]; then
		cp -a $srctree/$pf $WORKDIR/$pf
	fi
done

patch -p1 -bs -d $WORKDIR < $patchfile
sts=$?
if [ $sts -ne 0 ] && [ $force -eq 0 ]; then
	echo "patch errors, use '$PROG -f' to force continuation"
	rm -rf $WORKDIR
	exit 1
fi

for pf in $pfiles ; do
	$VIEWER $WORKDIR/$pf.orig $WORKDIR/$pf &
	if [ ${single} -eq 1 ]; then
		wait # for viewer to exit
	fi
done

if [ ${single} -eq 0 ]; then
	wait # for all viewers to exit
fi

rm -rf $WORKDIR