package main

import (
	"runtime/debug"
	"strings"
)

var (
	version   = "dev"
	gitCommit = "unknown"
	buildTime = "unknown"
)

type binaryBuildInfo struct {
	Version   string `json:"version"`
	GitCommit string `json:"git_commit"`
	BuildTime string `json:"build_time"`
}

func currentBuildInfo() binaryBuildInfo {
	out := binaryBuildInfo{
		Version:   version,
		GitCommit: gitCommit,
		BuildTime: buildTime,
	}

	if bi, ok := debug.ReadBuildInfo(); ok {
		if out.Version == "" || out.Version == "dev" {
			if bi.Main.Version != "" && bi.Main.Version != "(devel)" {
				out.Version = bi.Main.Version
			}
		}
		for _, s := range bi.Settings {
			if s.Key == "vcs.revision" && (out.GitCommit == "" || out.GitCommit == "unknown") {
				if len(s.Value) > 12 {
					out.GitCommit = s.Value[:12]
				} else {
					out.GitCommit = s.Value
				}
			}
			if s.Key == "vcs.time" && (out.BuildTime == "" || out.BuildTime == "unknown") {
				out.BuildTime = s.Value
			}
		}
	}

	out.Version = normalizeBuildField(out.Version, "dev")
	out.GitCommit = normalizeBuildField(out.GitCommit, "unknown")
	out.BuildTime = normalizeBuildField(out.BuildTime, "unknown")
	return out
}

func normalizeBuildField(v string, fallback string) string {
	v = strings.TrimSpace(v)
	if v == "" {
		return fallback
	}
	return v
}