i18n/translator.go

package i18n

import (
	"errors"
	"fmt"
)

/* NewTranslator creates closure data map and returns translation functions */
func NewTranslator(data map[string]map[string]string, defaultLang string) (func(string, string, ...any) string, func(string, string, ...any) error) {
	/* initialize map and copy data */
	translationMap := make(map[string]map[string]string, len(data))
	for lang, translation := range data {
		translationMap[lang] = make(map[string]string, len(translation))
		for key, value := range translation {
			translationMap[lang][key] = value
		}
	}
	/* T translates and returns localized string */
	T := func(lang string, key string, args ...any) string {
		/* attempt direct translation */
		if l, ok := translationMap[lang]; ok {
			if tr, ok := l[key]; ok {
				if len(args) == 0 {
					return tr
				}
				return fmt.Sprintf(tr, args...)
			}
		}
		/* fall back to default language */
		if l, ok := translationMap[defaultLang]; ok {
			if tr, ok := l[key]; ok {
				if len(args) == 0 {
					return tr
				}
				return fmt.Sprintf(tr, args...)
			}
		}
		/* no localized text, return key */
		return key
	}
	/* Terr translates localized string and returns it into error */
	Terr := func(lang string, key string, args ...any) error {
		return errors.New(T(lang, key, args...))
	}
	/* return functions */
	return T, Terr
}