From 4bfdda9b915c679d8b896a9e5538822e117bf511 Mon Sep 17 00:00:00 2001
From: Kailash Nadh <kailash@nadh.in>
Date: Tue, 26 Jan 2021 21:59:27 +0530
Subject: [PATCH] Load a default (en) language underneath the selected
 language.

The default language (en) is loaded first and the selected
language is loaded on top of it so that missing translation keys
in the selected language will have the original English strings
available on the UI.
---
 cmd/init.go           | 20 +++++++++++++++++---
 internal/i18n/i18n.go | 15 +++++++++++++++
 2 files changed, 32 insertions(+), 3 deletions(-)

diff --git a/cmd/init.go b/cmd/init.go
index b8c2595..598c75c 100644
--- a/cmd/init.go
+++ b/cmd/init.go
@@ -257,18 +257,32 @@ func initConstants() *constants {
 }
 
 // initI18n initializes a new i18n instance with the selected language map
-// loaded from the filesystem.
+// loaded from the filesystem. English is a loaded first as the default map
+// and then the selected language is loaded on top of it so that if there are
+// missing translations in it, the default English translations show up.
 func initI18n(lang string, fs stuffbin.FileSystem) *i18n.I18n {
-	b, err := fs.Read(fmt.Sprintf("/i18n/%s.json", lang))
+	const def = "en"
+
+	b, err := fs.Read(fmt.Sprintf("/i18n/%s.json", def))
 	if err != nil {
-		lo.Fatalf("error loading i18n language file: %v", err)
+		lo.Fatalf("error reading default i18n language file: %s: %v", def, err)
 	}
 
+	// Initialize with the default language.
 	i, err := i18n.New(b)
 	if err != nil {
 		lo.Fatalf("error unmarshalling i18n language: %v", err)
 	}
 
+	// Load the selected language on top of it.
+	b, err = fs.Read(fmt.Sprintf("/i18n/%s.json", lang))
+	if err != nil {
+		lo.Fatalf("error reading i18n language file: %v", err)
+	}
+	if err := i.Load(b); err != nil {
+		lo.Fatalf("error loading i18n language file: %v", err)
+	}
+
 	return i
 }
 
diff --git a/internal/i18n/i18n.go b/internal/i18n/i18n.go
index 391301a..c22b4b5 100644
--- a/internal/i18n/i18n.go
+++ b/internal/i18n/i18n.go
@@ -43,6 +43,21 @@ func New(b []byte) (*I18n, error) {
 	}, nil
 }
 
+// Load loads a JSON language map into the instance overwriting
+// existing keys that conflict.
+func (i *I18n) Load(b []byte) error {
+	var l map[string]string
+	if err := json.Unmarshal(b, &l); err != nil {
+		return err
+	}
+
+	for k, v := range l {
+		i.langMap[k] = v
+	}
+
+	return nil
+}
+
 // Name returns the canonical name of the language.
 func (i *I18n) Name() string {
 	return i.name