// Copyright 2022 The Prometheus Authors
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

//go:build go1.18
// +build go1.18

package version

import "runtime/debug"

var computedRevision string

func getRevision() string {
	if Revision != "" {
		return Revision
	}
	return computedRevision
}

func init() {
	computedRevision = computeRevision()
}

func computeRevision() string {
	var (
		rev      = "unknown"
		modified bool
	)

	buildInfo, ok := debug.ReadBuildInfo()
	if !ok {
		return rev
	}
	for _, v := range buildInfo.Settings {
		if v.Key == "vcs.revision" {
			rev = v.Value
		}
		if v.Key == "vcs.modified" {
			if v.Value == "true" {
				modified = true
			}
		}
	}
	if modified {
		return rev + "-modified"
	}
	return rev
}