// Package sdkversion says which mesh-sdk version a program was built with (novox/hq ADR 0446 clause 4: a composition
// check names its mesh-sdk version, so the controller and the assigner can be compared; ADR 0453 clause 1).
//
// The version is read from the build info, never kept by hand: a constant nobody bumps would report two different
// SDKs as one. A program that imports the SDK reports the module's pinned (pseudo-)version, or its replacement's;
// the SDK's own binaries and tests report "(devel)" with the stamped vcs.revision.
package sdkversion

import (
	"runtime/debug"
)

// Module is the SDK's Go module path.
const Module = "git.novox.be/novox/mesh-sdk/go"

// Version is the mesh-sdk version this binary was built with: "unknown" when the build carries no build info.
func Version() string {
	bi, ok := debug.ReadBuildInfo()
	if !ok {
		return "unknown"
	}
	return FromBuildInfo(bi)
}

// FromBuildInfo reads the SDK's version out of a build info. A dependency replaced by another module version is that
// version; replaced by a local path it is the path, never empty. When the SDK is the main module it is "(devel)",
// followed by a space and the vcs.revision when the build stamped one. Without the SDK in the build it is "unknown".
func FromBuildInfo(bi *debug.BuildInfo) string {
	if bi == nil {
		return "unknown"
	}
	if bi.Main.Path == Module {
		for _, s := range bi.Settings {
			if s.Key == "vcs.revision" && s.Value != "" {
				return "(devel) " + s.Value
			}
		}
		return "(devel)"
	}
	for _, d := range bi.Deps {
		if d == nil || d.Path != Module {
			continue
		}
		if r := d.Replace; r != nil {
			if r.Version != "" {
				return r.Version
			}
			if r.Path != "" {
				return r.Path
			}
		}
		if d.Version != "" {
			return d.Version
		}
	}
	return "unknown"
}