[MM-53968] Includes mattermost-plugin-api into the mono repo (#24235)

Include https://github.com/mattermost/mattermost-plugin-api into the mono repo

Co-authored-by: Jesse Hallam <jesse.hallam@gmail.com>
Co-authored-by: Michael Kochell <mjkochell@gmail.com>
Co-authored-by: Alejandro García Montoro <alejandro.garciamontoro@gmail.com>
Co-authored-by: Ben Schumacher <ben.schumacher@mattermost.com>
Co-authored-by: Alex Dovenmuehle <alex.dovenmuehle@mattermost.com>
Co-authored-by: Michael Kochell <6913320+mickmister@users.noreply.github.com>
Co-authored-by: Christopher Poile <cpoile@gmail.com>
Co-authored-by: İlker Göktuğ Öztürk <ilkergoktugozturk@gmail.com>
Co-authored-by: Shota Gvinepadze <wineson@gmail.com>
Co-authored-by: Ali Farooq <ali.farooq0@pm.me>
Co-authored-by: Maria A Nunez <maria.nunez@mattermost.com>
Co-authored-by: Daniel Espino García <larkox@gmail.com>
Co-authored-by: Christopher Speller <crspeller@gmail.com>
Co-authored-by: Alex Dovenmuehle <adovenmuehle@gmail.com>
Co-authored-by: Szymon Gibała <szymongib@gmail.com>
Co-authored-by: Lev <1187448+levb@users.noreply.github.com>
Co-authored-by: Jason Frerich <jason.frerich@mattermost.com>
Co-authored-by: Agniva De Sarker <agnivade@yahoo.co.in>
Co-authored-by: Artur M. Wolff <artur.m.wolff@gmail.com>
Co-authored-by: Madhav Hugar <16546715+madhavhugar@users.noreply.github.com>
Co-authored-by: Joe <security.joe@pm.me>
Co-authored-by: Ibrahim Serdar Acikgoz <serdaracikgoz86@gmail.com>
Co-authored-by: José Peso <trilopin@users.noreply.github.com>

server/public/pluginapi/i18n/i18n.go

@@ -0,0 +1,136 @@
+package i18n
+
+import (
+	"encoding/json"
+	"os"
+	"path/filepath"
+	"strings"
+
+	"github.com/nicksnyder/go-i18n/v2/i18n"
+	"github.com/pkg/errors"
+	"golang.org/x/text/language"
+
+	"github.com/mattermost/mattermost/server/public/model"
+)
+
+// PluginAPI is the plugin API interface required to manage translations.
+type PluginAPI interface {
+	GetBundlePath() (string, error)
+	GetConfig() *model.Config
+	GetUser(userID string) (*model.User, *model.AppError)
+	LogWarn(msg string, keyValuePairs ...interface{})
+}
+
+// Message is a string that can be localized.
+//
+// See https://pkg.go.dev/github.com/nicksnyder/go-i18n/v2/i18n?tab=doc#Message for more details.
+type Message = i18n.Message
+
+// LocalizeConfig configures a call to the Localize method on Localizer.
+//
+// See https://pkg.go.dev/github.com/nicksnyder/go-i18n/v2/i18n?tab=doc#LocalizeConfig for more details.
+type LocalizeConfig = i18n.LocalizeConfig
+
+// Localizer provides Localize and MustLocalize methods that return localized messages.
+//
+// See https://pkg.go.dev/github.com/nicksnyder/go-i18n/v2/i18n?tab=doc#Localizer for more details.
+type Localizer = i18n.Localizer
+
+// Bundle stores a set of messages and pluralization rules.
+// Most plugins only need a single bundle
+// that is initialized on activation.
+// It is not goroutine safe to modify the bundle while Localizers
+// are reading from it.
+type Bundle struct {
+	*i18n.Bundle
+	api PluginAPI
+}
+
+// InitBundle loads all localization files  from a given path into a bundle and return this.
+// path is a relative path in the plugin bundle, e.g. assets/i18n.
+// Every file except the ones named active.*.json.
+// The default language is English.
+func InitBundle(api PluginAPI, path string) (*Bundle, error) {
+	bundle := &Bundle{
+		Bundle: i18n.NewBundle(language.English),
+		api:    api,
+	}
+	bundle.RegisterUnmarshalFunc("json", json.Unmarshal)
+
+	bundlePath, err := api.GetBundlePath()
+	if err != nil {
+		return nil, errors.Wrap(err, "failed to get bundle path")
+	}
+
+	i18nDir := filepath.Join(bundlePath, path)
+
+	files, err := os.ReadDir(i18nDir)
+	if err != nil {
+		return nil, errors.Wrap(err, "failed to open i18n directory")
+	}
+
+	for _, file := range files {
+		if !strings.HasPrefix(file.Name(), "active.") {
+			continue
+		}
+
+		if !strings.HasSuffix(file.Name(), ".json") {
+			continue
+		}
+
+		if file.Name() == "active.en.json" {
+			continue
+		}
+
+		_, err = bundle.LoadMessageFile(filepath.Join(i18nDir, file.Name()))
+		if err != nil {
+			return nil, errors.Wrapf(err, "failed to load message file %s", file.Name())
+		}
+	}
+
+	return bundle, nil
+}
+
+// GetUserLocalizer returns a localizer that localizes in the users locale.
+func (b *Bundle) GetUserLocalizer(userID string) *i18n.Localizer {
+	user, err := b.api.GetUser(userID)
+	if err != nil {
+		b.api.LogWarn("Failed get user's locale", "error", err.Error())
+		return b.GetServerLocalizer()
+	}
+
+	return i18n.NewLocalizer(b.Bundle, user.Locale)
+}
+
+// GetServerLocalizer returns a localizer that localizes in the default server locale.
+//
+// This is useful for situations where a messages is shown to every user,
+// independent of the users locale.
+func (b *Bundle) GetServerLocalizer() *i18n.Localizer {
+	local := *b.api.GetConfig().LocalizationSettings.DefaultServerLocale
+
+	return i18n.NewLocalizer(b.Bundle, local)
+}
+
+// LocalizeDefaultMessage localizer the provided message.
+// An empty string is returned when the localization fails.
+func (b *Bundle) LocalizeDefaultMessage(l *Localizer, m *Message) string {
+	s, err := l.LocalizeMessage(m)
+	if err != nil {
+		b.api.LogWarn("Failed to localize message", "message ID", m.ID, "error", err.Error())
+		return ""
+	}
+
+	return s
+}
+
+// LocalizeWithConfig localizer the provided localize config.
+// An empty string is returned when the localization fails.
+func (b *Bundle) LocalizeWithConfig(l *Localizer, lc *LocalizeConfig) string {
+	s, err := l.Localize(lc)
+	if err != nil {
+		b.api.LogWarn("Failed to localize with config", "error", err.Error())
+		return ""
+	}
+	return s
+}