listmonk/internal/i18n/i18n.go
2021-01-23 18:54:33 +05:30

140 lines
3.3 KiB
Go

package i18n
import (
"encoding/json"
"regexp"
"strings"
)
// Lang represents a loaded language.
type Lang struct {
Code string `json:"code"`
Name string `json:"name"`
langMap map[string]string
}
// I18nLang is a simple i18n library that translates strings using a language map.
// It mimicks some functionality of the vue-i18n library so that the same JSON
// language map may be used in the JS frontent and the Go backend.
type I18nLang struct {
Code string `json:"code"`
Name string `json:"name"`
langMap map[string]string
}
var reParam = regexp.MustCompile(`(?i)\{([a-z0-9-.]+)\}`)
// New returns an I18n instance.
func New(code string, b []byte) (*I18nLang, error) {
var l map[string]string
if err := json.Unmarshal(b, &l); err != nil {
return nil, err
}
return &I18nLang{
langMap: l,
}, nil
}
// JSON returns the languagemap as raw JSON.
func (i *I18nLang) JSON() []byte {
b, _ := json.Marshal(i.langMap)
return b
}
// T returns the translation for the given key similar to vue i18n's t().
func (i *I18nLang) T(key string) string {
s, ok := i.langMap[key]
if !ok {
return key
}
return i.getSingular(s)
}
// Ts returns the translation for the given key similar to vue i18n's t()
// and subsitutes the params in the given map in the translated value.
// In the language values, the substitutions are represented as: {key}
// The params and values are received as a pairs of succeeding strings.
// That is, the number of these arguments should be an even number.
// eg: Ts("globals.message.notFound",
// "name", "campaigns",
// "error", err)
func (i *I18nLang) Ts(key string, params ...string) string {
if len(params)%2 != 0 {
return key + `: Invalid arguments`
}
s, ok := i.langMap[key]
if !ok {
return key
}
s = i.getSingular(s)
for n := 0; n < len(params); n += 2 {
// If there are {params} in the param values, substitute them.
val := i.subAllParams(params[n+1])
s = strings.ReplaceAll(s, `{`+params[n]+`}`, val)
}
return s
}
// Tc returns the translation for the given key similar to vue i18n's tc().
// It expects the language string in the map to be of the form `Singular | Plural` and
// returns `Plural` if n > 1, or `Singular` otherwise.
func (i *I18nLang) Tc(key string, n int) string {
s, ok := i.langMap[key]
if !ok {
return key
}
// Plural.
if n > 1 {
return i.getPlural(s)
}
return i.getSingular(s)
}
// getSingular returns the singular term from the vuei18n pipe separated value.
// singular term | plural term
func (i *I18nLang) getSingular(s string) string {
if !strings.Contains(s, "|") {
return s
}
return strings.TrimSpace(strings.Split(s, "|")[0])
}
// getSingular returns the plural term from the vuei18n pipe separated value.
// singular term | plural term
func (i *I18nLang) getPlural(s string) string {
if !strings.Contains(s, "|") {
return s
}
chunks := strings.Split(s, "|")
if len(chunks) == 2 {
return strings.TrimSpace(chunks[1])
}
return strings.TrimSpace(chunks[0])
}
// subAllParams recursively resolves and replaces all {params} in a string.
func (i *I18nLang) subAllParams(s string) string {
if !strings.Contains(s, `{`) {
return s
}
parts := reParam.FindAllStringSubmatch(s, -1)
if len(parts) < 1 {
return s
}
for _, p := range parts {
s = strings.ReplaceAll(s, p[0], i.T(p[1]))
}
return i.subAllParams(s)
}