Convert TranslationSets to json (#3649)HEADmaster

- **PR Description**

This lays the ground for translating lazygit's texts using a translation
system such as Crowdin, Weblate, or Poeditor.

See #3070.

1 files changed, 85 insertions, 25 deletions

diff --git a/pkg/i18n/i18n.go b/pkg/i18n/i18n.go
index d7358775f..ea5fcbb06 100644
--- a/pkg/i18n/i18n.go
+++ b/pkg/i18n/i18n.go
@@ -1,60 +1,120 @@
 package i18n
 
 import (
+	"embed"
+	"encoding/json"
+	"io/fs"
+	"path/filepath"
 	"strings"
 
 	"github.com/cloudfoundry/jibber_jabber"
 	"github.com/go-errors/errors"
 	"github.com/imdario/mergo"
+	"github.com/samber/lo"
 	"github.com/sirupsen/logrus"
 )
 
-// Localizer will translate a message into the user's language
-type Localizer struct {
-	Log *logrus.Entry
-	S   TranslationSet
-}
-
 func NewTranslationSetFromConfig(log *logrus.Entry, configLanguage string) (*TranslationSet, error) {
+	languageCodes, err := getSupportedLanguageCodes()
+	if err != nil {
+		return nil, err
+	}
+
 	if configLanguage == "auto" {
 		language := detectLanguage(jibber_jabber.DetectIETF)
-		return NewTranslationSet(log, language), nil
+		for _, languageCode := range languageCodes {
+			if strings.HasPrefix(language, languageCode) {
+				return newTranslationSet(log, language)
+			}
+		}
+
+		// Detecting a language that we don't have a translation for is not an
+		// error, we'll just use English.
+		return EnglishTranslationSet(), nil
 	}
 
-	for key := range GetTranslationSets() {
+	if configLanguage == "en" {
+		return EnglishTranslationSet(), nil
+	}
+
+	for _, key := range languageCodes {
 		if key == configLanguage {
-			return NewTranslationSet(log, configLanguage), nil
+			return newTranslationSet(log, configLanguage)
 		}
 	}
 
-	return NewTranslationSet(log, "en"), errors.New("Language not found: " + configLanguage)
+	// Configuring a language that we don't have a translation for *is* an
+	// error, though.
+	return nil, errors.New("Language not found: " + configLanguage)
 }
 
-func NewTranslationSet(log *logrus.Entry, language string) *TranslationSet {
+func newTranslationSet(log *logrus.Entry, language string) (*TranslationSet, error) {
 	log.Info("language: " + language)
 
 	baseSet := EnglishTranslationSet()
 
-	for languageCode, translationSet := range GetTranslationSets() {
-		if strings.HasPrefix(language, languageCode) {
-			_ = mergo.Merge(&baseSet, translationSet, mergo.WithOverride)
+	if language != "en" {
+		translationSet, err := readLanguageFile(language)
+		if err != nil {
+			return nil, err
+		}
+		err = mergo.Merge(baseSet, *translationSet, mergo.WithOverride)
+		if err != nil {
+			return nil, err
 		}
 	}
-	return &baseSet
+
+	return baseSet, nil
+}
+
+//go:embed translations/*.json
+var embedFS embed.FS
+
+// getSupportedLanguageCodes gets all the supported language codes.
+// Note: this doesn't include "en"
+func getSupportedLanguageCodes() ([]string, error) {
+	dirEntries, err := embedFS.ReadDir("translations")
+	if err != nil {
+		return nil, err
+	}
+	return lo.Map(dirEntries, func(entry fs.DirEntry, _ int) string {
+		return strings.TrimSuffix(entry.Name(), ".json")
+	}), nil
+}
+
+func readLanguageFile(languageCode string) (*TranslationSet, error) {
+	jsonData, err := embedFS.ReadFile(filepath.Join("translations", languageCode+".json"))
+	if err != nil {
+		return nil, err
+	}
+	var translationSet TranslationSet
+	err = json.Unmarshal(jsonData, &translationSet)
+	if err != nil {
+		return nil, err
+	}
+	return &translationSet, nil
 }
 
 // GetTranslationSets gets all the translation sets, keyed by language code
-func GetTranslationSets() map[string]TranslationSet {
-	return map[string]TranslationSet{
-		"pl":    polishTranslationSet(),
-		"nl":    dutchTranslationSet(),
-		"en":    EnglishTranslationSet(),
-		"zh-CN": chineseTranslationSet(), // Simplified Chinese
-		"zh-TW": traditionalChineseTranslationSet(),
-		"ja":    japaneseTranslationSet(),
-		"ko":    koreanTranslationSet(),
-		"ru":    RussianTranslationSet(),
+// This includes "en".
+func GetTranslationSets() (map[string]*TranslationSet, error) {
+	languageCodes, err := getSupportedLanguageCodes()
+	if err != nil {
+		return nil, err
 	}
+
+	result := make(map[string]*TranslationSet)
+	result["en"] = EnglishTranslationSet()
+
+	for _, languageCode := range languageCodes {
+		translationSet, err := readLanguageFile(languageCode)
+		if err != nil {
+			return nil, err
+		}
+		result[languageCode] = translationSet
+	}
+
+	return result, nil
 }
 
 // detectLanguage extracts user language from environment