package version

import "runtime/debug"

// VERSION contains version information. It is set at build time via
// -ldflags "-X github.com/oauth2-proxy/oauth2-proxy/v7/pkg/version.VERSION=<version>".
// When the binary is built without those flags (for example via
// `go install github.com/oauth2-proxy/oauth2-proxy/v7@latest`), it falls back
// to the module version recorded in the build info so that `--version` still
// reports a meaningful value instead of "undefined".
var VERSION = "undefined"

func init() {
	VERSION = resolveVersion(VERSION, debug.ReadBuildInfo)
}

// resolveVersion returns ldflagsVersion when it has been explicitly set at
// build time. Otherwise it derives the version from the module build info,
// allowing `go install`-ed binaries to report a meaningful version.
func resolveVersion(ldflagsVersion string, readBuildInfo func() (*debug.BuildInfo, bool)) string {
	if ldflagsVersion != "" && ldflagsVersion != "undefined" {
		return ldflagsVersion
	}
	if info, ok := readBuildInfo(); ok && info != nil {
		// info.Main.Version is populated by the Go toolchain only for
		// module-aware builds: it is the clean tag for an exact
		// `@vX.Y.Z` install, or a synthesized pseudo-version
		// (e.g. v7.15.4-0.20240115123456-abcdef123456) carrying the
		// base version, commit timestamp and hash when built from
		// commits on top of a release. A plain `go build` from a source
		// checkout reports "(devel)", which we skip so release builds
		// keep deferring to the ldflags value below.
		if v := info.Main.Version; v != "" && v != "(devel)" {
			return v
		}
	}
	return ldflagsVersion
}