#!/bin/bash
#
# usage: ipkg-revision <some.ipk> 
#                      [new upstream revision or - for no # change]
#                      [new packet revision or + for increment]
#
# Output: 
#

TMPDIR=`mktemp -d /tmp/ptxdist.XXXXXX`
IPKG=$1
IPKG_DIR=`dirname $IPKG`
NEW_REV_PART=$2
NEW_PKG_PART=$3

PREFIX=`basename $0`

usage() {
        echo 
        [ -n "$1" ] && echo -e "${PREFIX} error: $1\n"
        echo "usage: $0 <some.ipk> [upstream revision] [packet revision]"
	echo
	echo "upstream revision: '-': no change"
	echo "packet revision:   '+': increment"
        echo
        exit 0
}

#
# Sanity checks
#
[ -z "$IPKG" ]        && usage "${PREFIX} error: specify ipkg packet dir as first argument"

if [ ! -f "$IPKG" ]; then
	echo -e "\nError: couldn't find $IPKG\n"
	exit 1
fi

mkdir -p ${TMPDIR}/control
pushd ${TMPDIR} 2>&1 > /dev/null

#
# Extract control.tar.gz and find out 
# upstream version and packet version
#

ar x $IPKG
cd control 
tar -zxf ../control.tar.gz
REVISION=`grep -e "^Version[\t ]*:.*" control | sed -e "s/Version[\t ]*:[\t ]*//g" `
PACKAGE=`grep -e "^Package[\t ]*:.*" control | sed -e "s/Package[\t ]*:[\t ]*//g"`
ARCH=`grep -e "^Architecture[\t ]*:.*" control | sed -e "s/Architecture[\t ]*:[\t ]*//g"`

# REVISION contains no "-"? -> we have only an upstream revision, no
# packet revision
if [ "`echo $REVISION | grep '-'`" = "" ]; then
	REV_PART="$REVISION"
	PKG_PART=""
else
	REV_PART=`echo $REVISION | sed -e "s/-.*$//g"`
	PKG_PART=`echo $REVISION | sed -e "s/^.*-//g"`
fi

#
# No new revisions? Print out info only
#
if [ "$NEW_REV_PART" = "" ] && [ "$NEW_PKG_PART" = "" ]; then
	echo "$REV_PART $PKG_PART"
	exit 1
fi

if [ "$NEW_REV_PART" = "-" ] && [ "$NEW_PKG_PART" = "" ]; then
	echo "$REV_PART $PKG_PART"
	exit 1
fi

#
# We have found out the revisions now; construct the new ones according
# to what the user has specified on the command line. 
#

[ "$PKG_PART" = "" ] && PKG_PART=0

[ "$NEW_REV_PART" = "-" ] && NEW_REV_PART=$REV_PART

if [ "$NEW_PKG_PART" = "+" ]; then
	NEW_PKG_PART=$((++PKG_PART))
else if [ "$NEW_PKG_PART" = "" ]; then
	NEW_PKG_PART=$PKG_PART
fi
fi

[ "$NEW_PKG_PART" != "" ] && NEW_PKG_PART="-$NEW_PKG_PART"

#
# Now we have the new values
#

if [ -e "${IPKG_DIR}/${PACKAGE}_${NEW_REV_PART}${NEW_PKG_PART}_${ARCH}.ipk" ]; then
	echo "${PREFIX} error: ${IPKG_DIR}/${PACKAGE}_${NEW_REV_PART}${NEW_PKG_PART}_${ARCH}.ipk already exists" >&2
	echo ${IPKG_DIR}/${PACKAGE}_${NEW_REV_PART}${NEW_PKG_PART}_${ARCH}.ipk
	rm -fr ${TMPDIR}
	exit 1
fi

sed -i -e "s/^Version.*/Version:        ${NEW_REV_PART}${NEW_PKG_PART}/g" control

#
# re-package the package
#

tar -zcf ../control-new.tar.gz .

cd ..
rm -fr control
mv control-new.tar.gz control.tar.gz

ar r ${IPKG_DIR}/${PACKAGE}_${NEW_REV_PART}${NEW_PKG_PART}_${ARCH}.ipk `find .  -type f` > /dev/null

#
# ok, finished, cleanup
#

popd 2>&1 > /dev/null

echo ${PACKAGE}_${NEW_REV_PART}${NEW_PKG_PART}_${ARCH}.ipk

rm -fr ${TMPDIR}