#!/usr/bin/env bash
# Shows a diff between repo databases

. libremessages

usage() {
	print "Usage: %s arch/core/i686 parabola/core/i686" "${0##*/}"
	print "Compares two repo databases using distro/repo/architecture format."
	echo
	print 'Shortcuts:'
	flag 'arch'     'expands to Arch Linux repo url'
	flag 'parabola' 'expands to Parabola GNU/Linux-libre repo url'
}

if test $# -eq 0; then
	usage
	exit 0
fi

b() { bsdtar ztf $1 | cut -d "/" -f1 | sort -u ; }
n() { echo "$1".db | tr "/" "-"; }

# hopefully simple way to convert
# parabola/libre/i686
# to
# http://repo.parabolagnulinux.org/libre/os/i686/libre.db
# add more distros here
g() {
	echo "$1" | sed -e "s,^\([^/]\+\)/\([^/]\+\)/\([^/]\+\)$,\1/\2/os/\3/\2.db," \
	                -e "s,^parabola/,http://repo.parabolagnulinux.org/," \
	                -e "s,^arch\(linux\)\?/,http://mirrors.kernel.org/archlinux/,"
}

mkdir ${0##*/}.$$
pushd ${0##*/}.$$ >/dev/null

d=""
for i in $1 $2; do
	n=$(n "$i")

	test -z "$n" && exit 1

	wget -O "$n" -nv $(g "$i")
	b "$n" >${n}.orig

	d+=" ${n}.orig"
done

{
	printf "$(gettext "Difference between %s and %s")\n---\n" $1 $2
	which diffstat &>/dev/null && diff -auN "${d[@]}" | diffstat
	diff -auN "${d[@]}"
} >../${n}.diff

popd >/dev/null
rm -r ${0##*/}.$$

print "Difference save on %s" "${n}.diff"