feat(i18n): enrich service state snapshot

Co-Authored-By: Virgil <virgil@lethean.io>

i18n.go

@@ -182,6 +182,8 @@ func CurrentDebug() bool {
 func State() ServiceState {
 	return defaultServiceValue(ServiceState{
 		Language:           "en",
+		RequestedLanguage:  "",
+		LanguageExplicit:   false,
 		AvailableLanguages: []string{},
 		Mode:               ModeNormal,
 		Fallback:           "en",

service_test.go

@@ -193,6 +193,12 @@ func TestServiceCurrentStateAliases(t *testing.T) {
 	if got, want := svc.CurrentState(), svc.State(); len(got.AvailableLanguages) != len(want.AvailableLanguages) || len(got.Handlers) != len(want.Handlers) {
 		t.Fatalf("CurrentState() = %+v, want %+v", got, want)
 	}
+	if got, want := svc.CurrentState().RequestedLanguage, svc.State().RequestedLanguage; got != want {
+		t.Fatalf("CurrentState().RequestedLanguage = %q, want %q", got, want)
+	}
+	if got, want := svc.CurrentState().LanguageExplicit, svc.State().LanguageExplicit; got != want {
+		t.Fatalf("CurrentState().LanguageExplicit = %t, want %t", got, want)
+	}
 }
 
 func TestServiceCurrentStateAliasesReturnCopies(t *testing.T) {
@@ -249,6 +255,8 @@ func TestServiceStateString(t *testing.T) {
 	for _, want := range []string{
 		"ServiceState{",
 		"language=",
+		"requested=",
+		"explicit=",
 		"fallback=",
 		"mode=",
 		"available=",

state.go

@@ -8,6 +8,8 @@ import (
 // copy-safe snapshot.
 type ServiceState struct {
 	Language           string
+	RequestedLanguage  string
+	LanguageExplicit   bool
 	AvailableLanguages []string
 	Mode               Mode
 	Fallback           string
@@ -38,8 +40,10 @@ func (s ServiceState) String() string {
 		handlers = "[" + core.Join(", ", names...) + "]"
 	}
 	return core.Sprintf(
-		"ServiceState{language=%q fallback=%q mode=%s formality=%s location=%q direction=%s rtl=%t debug=%t available=%s handlers=%d types=%s}",
+		"ServiceState{language=%q requested=%q explicit=%t fallback=%q mode=%s formality=%s location=%q direction=%s rtl=%t debug=%t available=%s handlers=%d types=%s}",
 		s.Language,
+		s.RequestedLanguage,
+		s.LanguageExplicit,
 		s.Fallback,
 		s.Mode,
 		s.Formality,
@@ -57,6 +61,8 @@ func (s *Service) State() ServiceState {
 	if s == nil {
 		return ServiceState{
 			Language:           "en",
+			RequestedLanguage:  "",
+			LanguageExplicit:   false,
 			AvailableLanguages: []string{},
 			Mode:               ModeNormal,
 			Fallback:           "en",
@@ -85,6 +91,8 @@ func (s *Service) State() ServiceState {
 
 	return ServiceState{
 		Language:           s.currentLang,
+		RequestedLanguage:  s.requestedLang,
+		LanguageExplicit:   s.languageExplicit,
 		AvailableLanguages: langs,
 		Mode:               s.mode,
 		Fallback:           s.fallbackLang,