#!/bin/sh
######################################################################
# dpkg-unpack-build                                      December 2005
# Horms                                             horms@verge.net.au
#
# dpkg-unpack-build
# Unpack a tarball or dsc file and build a debian package using 
# debuild(1)
# Copyright (C) 2005  Horms <horms@verge.net.au>
# 
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License as
# published by the Free Software Foundation; either version 2 of the
# License, or (at your option) any later version.
# 
# This program is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
# General Public License for more details.
# 
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
# 02111-1307  USA
#
######################################################################

set -e

NAME="`basename $0`"

usage ()
{
	echo "Usage: $NAME TARBALL|DSC [DEBBUILD_ARGS]" >&2
	exit 1
}

unpack_tar ()
{
	local TAR TARDIR TARFLAGS UNPACKDIR BUILDDIR
	TAR="$1"

	case $TAR in
		*gz)
			TARFLAGS="--gzip" ;;
		*bz2)
			TARFLAGS="--bzip2" ;;
		*)
			TARFLAGS="" ;;
	esac

	TARDIR=`tar "$TARFLAGS" -stf "$TAR" | head -1`
	if [ "$TARDIR" = "./" ]; then
		UNPACKDIR="$PWD/t"
		BUILDDIR="$PWD/t"
	else
		UNPACKDIR="$PWD"
		BUILDDIR="$PWD/$TARDIR"
	fi
	
	if ! tar "$TARFLAGS" -tf "$TAR" "${TARDIR}debian/" >& /dev/null; then
		echo "No debian/ directory in tarball" >&2
		exit 1
	fi
	
	if [ -e "$BUILDDIR" ]; then
		echo -n "$NAME: $BUILDDIR already exists, please move it " >&2
		echo "out of the way or build by debuild in that directory" >&2
		exit 1
	fi
	
	tar "$TARFLAGS" -C "$UNPACKDIR" -xf "$TAR"

	echo "$BUILDDIR"
}


unpack_dsc ()
{
	local DSC BUILDDIR NAME_VERSION VERSION NAME
	DSC="$1"

	NAME_VERSION="${DSC%-*}"
	VERSION="${NAME_VERSION##*_}"
	NAME="${NAME_VERSION%_*}"
	BUILDDIR="$PWD/$NAME-$VERSION"
	
	if [ -e "$BUILDDIR" ]; then
		echo -n "$NAME: $BUILDDIR already exists, please move it " >&2
		echo "out of the way or build by debuild in that directory" >&2
		exit 1
	fi
	
	dpkg-source -x "$DSC" > /dev/null
	echo "$BUILDDIR"
}

if [ $# == 0 ]; then
	usage
fi

FILE="$1"
shift

case $FILE in
	*dsc)
		BUILDDIR="`unpack_dsc $FILE`" ;;
	*)
		BUILDDIR="`unpack_tar $FILE`" ;;
esac

echo "Building in $BUILDDIR"
(cd "$BUILDDIR" && debuild $@; )
rm -r "$BUILDDIR"