// Package version exposes build metadata injected at link time.
package version

import (
	"fmt"
	"runtime"
	"runtime/debug"
	"sync"
)

// Injected via -ldflags "-X github.com/iceBear67/simplepages/internal/version.Version=...".
var (
	Version = "dev"
	Commit  = ""
	Date    = ""
)

var once sync.Once

// vcsFromBuildInfo fills Commit/Date from the embedded build info when the
// linker flags were not supplied (the usual case for `go run` and `go install`).
func vcsFromBuildInfo() {
	info, ok := debug.ReadBuildInfo()
	if !ok {
		return
	}
	for _, s := range info.Settings {
		switch s.Key {
		case "vcs.revision":
			if Commit == "" {
				Commit = s.Value
			}
		case "vcs.time":
			if Date == "" {
				Date = s.Value
			}
		}
	}
}

// String renders a one-line human-readable version banner.
func String() string {
	once.Do(vcsFromBuildInfo)
	s := Version
	if Commit != "" {
		short := Commit
		if len(short) > 12 {
			short = short[:12]
		}
		s += "+" + short
	}
	if Date != "" {
		s += " (" + Date + ")"
	}
	return fmt.Sprintf("%s %s/%s %s", s, runtime.GOOS, runtime.GOARCH, runtime.Version())
}

// Short returns just the version string, for API responses.
func Short() string {
	once.Do(vcsFromBuildInfo)
	if Commit == "" {
		return Version
	}
	short := Commit
	if len(short) > 12 {
		short = short[:12]
	}
	return Version + "+" + short
}