#!/usr/bin/env sh

# Copyright (c) 2020 Tailscale Inc & AUTHORS All rights reserved.
# Use of this source code is governed by a BSD-style
# license that can be found in the LICENSE file.

# Print the version tailscale repository corresponding
# to the version listed in go.mod.

set -euo pipefail

go_list=$(go list -m tailscale.com)
# go list outputs `tailscale.com <version>`. Extract the version.
mod_version=${go_list##* }

if [ -z "$mod_version" ]; then
	echo "no version reported by go list -m tailscale.com: $go_list"
	exit 1
fi

case "$mod_version" in
	*-*-*)
		# A pseudo-version such as "v1.1.1-0.20201030135043-eab6e9ea4e45"
		# includes the commit hash.
		mod_version=${mod_version##*-*-}
		;;
esac

tailscale_clone=/tmp/tailscale-clone

if [ ! -d "$tailscale_clone" ]; then
       git clone -q https://github.com/tailscale/tailscale.git "$tailscale_clone"
fi

cd $tailscale_clone
git reset --hard -q
git clean -d -x -f
git fetch -q --all --tags
git checkout -q "$mod_version"
echo $mod_version-`git describe --always --exclude "*" --dirty --abbrev=$1`