#!/bin/sh
# SPDX-FileCopyrightText: (C) 2024 Oswald Buddenhagen <ossi@users.sf.net>
# SPDX-License-Identifier: GPL-2.0-or-later

cd $(dirname $0)

test -e .git || exit

mb=$(git merge-base HEAD "@{upstream}" 2> /dev/null)
if test -z "$mb"; then
	# we presume that a failure to find a merge base means no upstream.
	# and no upstream may mean detached head in the middle of a rebase
	br=$(git branch | sed -n -e 's/^\* (no branch, rebasing \([^\)]*\))$/\1/p')
	if test -n "$br"; then
		mb=$(git merge-base HEAD "$br@{upstream}" 2> /dev/null)
	fi
fi
if test -z "$mb"; then
	# still no upstream, so just describe HEAD as-is.
	gver=$(git describe --always --tags HEAD)
else
	# find out whether we have local work, and if so, collapse it into
	# a single suffix. otherwise, we'd cause pointless rebuilds during
	# development.
	gver=$(git describe --always --tags $mb)
	lcl=$(git rev-list -n 1 $mb..HEAD)
	if test -n "$lcl"; then
		gver="$gver-plus"
	fi
fi
gver=${gver#v}
pgver=$(cat VERSION 2> /dev/null)
if [ "x$gver" != "x$pgver" ]; then
	echo "$gver" > VERSION
fi