#!/bin/bash
# vi: ts=4 noexpandtab

# these urls are for lucid release version of grub
i386_url="https://launchpad.net/ubuntu/+archive/primary/+files/grub_0.97-29ubuntu60_i386.deb"
x86_64_url="https://launchpad.net/ubuntu/+archive/primary/+files/grub_0.97-29ubuntu60_amd64.deb"
TEMP_D=""

Usage() {
	cat <<EOF
Usage: ${0##*/} out_d
	prepare out_d for grub
	creates 'bootgrub.tar' and 'grub' binary
EOF
}
cleanup() {
	[ -z "${TEMP_D}" -o ! -d "${TEMP_D}" ] || rm -Rf "${TEMP_D}"
}
error() { echo "$@" 1>&2; }
fail() { [ $# -eq 0 ] || error "$@"; exit 1; }

[ "$1" = "-h" -o "$1" = "--help" ] && { Usage; exit 0; }
[ $# -eq 1 ] || { Usage 1>&2; error "must give out_d"; exit 1; }
out_d_in=$1

mkdir -p "$out_d_in" || fail "failed to make $out_d"
out_d=$(cd "$out_d_in" && pwd)
mkdir -p "$out_d/dl"

case "$(uname -m)" in
	x86_64) url="${x86_64_url}";;
	i?86) url="${i386_url}";;
esac

TEMP_D=$(mktemp -d "${TMPDIR:-/tmp}/.${0##*/}.XXXXXX") ||
	fail "failed to make tempd"
trap cleanup EXIT

deb="${out_d}/dl/${url##*/}"
if [ ! -e "${deb}" ]; then
	wget "${url}" -O "${TEMP_D}/deb" &&
		mv "${TEMP_D}/deb" "$deb" || fail "failed download of ${url}"
fi

cd "${TEMP_D}"
dpkg -x "$deb" . &&
	cp usr/sbin/grub "$out_d/grub" &&
	mkdir -p boot/grub &&
	cp usr/lib/grub/*/{stage1,stage2,e2fs_stage1_5} boot/grub &&
	tar cf "${out_d}/bootgrub.tar" boot/ ||
	fail "failed to create $out_d"
exit 0