[skip-changelog] I18n fetch language codes from transifex (arduino#736)

* fetch available languages from transifex

* fix documentation on i18n update

* add documentation on contributing for i18n workflow

Author: hdiniz

Taskfile.yml

@@ -124,7 +124,7 @@ tasks:
   i18n:pull:
     desc: Pull i18n files from transifex
     cmds:
-      - go run ./i18n/cmd/main.go transifex pull -l {{.I18N_LANGS}} ./i18n/data
+      - go run ./i18n/cmd/main.go transifex pull ./i18n/data
       - task: i18n:generate
 
   i18n:push:
@@ -169,4 +169,3 @@ vars:
   DOCS_VERSION: dev
   DOCS_ALIAS: ""
   DOCS_REMOTE: "origin"
-  I18N_LANGS: "pt_BR"

docs/CONTRIBUTING.md

@@ -190,6 +190,43 @@ a list of items you can check before submitting a PR:
   failures that seem
   not related to the change you are making.
 
+## Internationalization (i18n)
+
+In order to support i18n in the cli, any messages that are intended to be translated 
+should be wrapped in a call to `i18n.Tr`. This call allows us to build a catalog of 
+translatable strings, replacing the reference string at runtime with the localized value.
+
+Adding or modifying these messages requires an i18n update, as this process creates the
+reference catalog that are shared with translators. For that reason, the `task check`
+command will fail if the catalog was not updated to sync with changes to the source code.
+
+To update the catalog, execute the following command and commit the changes.
+
+```shell
+task i18n:update
+```
+
+To verify that the catalog is up-to-date, you may execute the command:
+
+```shell
+task i18n:check
+```
+
+Example usage:
+
+```golang
+package main
+
+import (
+  "fmt"
+  "github.com/arduino/arduino-cli/i18n"
+)
+
+func main() {
+  fmt.Println(i18n.Tr("Hello World!"))
+}
+```
+
 ## Additional settings
 
 If you need to push a commit that's only shipping documentation changes or

i18n/README.md

@@ -42,12 +42,3 @@ task i18n:push
 ```sh
 task i18n:pull
 ```
-
-## Adding a new language
-
-To add a new supported language add the locale string to the project's Taskfile.yml (comma separated list)
-
-e.g
-```
-I18N_LANGS: "pt_BR,es,jp"
-```

i18n/cmd/commands/transifex/pull_transifex.go

@@ -16,6 +16,7 @@
 package transifex
 
 import (
+	"encoding/json"
 	"fmt"
 	"io/ioutil"
 	"net/http"
@@ -26,20 +27,62 @@ import (
 )
 
 var pullTransifexCommand = &cobra.Command{
-	Use:   "pull -l pt_BR [catalog folder]",
+	Use:   "pull [catalog folder]",
 	Short: "pulls the translation files from transifex",
-	Args:  cobra.ExactArgs(1),
 	Run:   pullCatalog,
 }
 
-var languages = []string{}
+func getLanguages() []string {
+	req, err := http.NewRequest(
+		"GET",
+		fmt.Sprintf(
+			"https://www.transifex.com/api/2/project/%s/resource/%s/stats/",
+			project, resource,
+		), nil)
+
+	if err != nil {
+		fmt.Println(err.Error())
+		os.Exit(1)
+	}
+
+	req.SetBasicAuth("api", apiKey)
+
+	resp, err := http.DefaultClient.Do(req)
+
+	if err != nil {
+		fmt.Println(err.Error())
+		os.Exit(1)
+	}
+
+	defer resp.Body.Close()
+
+	b, err := ioutil.ReadAll(resp.Body)
+	if err != nil {
+		fmt.Println(err.Error())
+		os.Exit(1)
+	}
+
+	var jsonResp map[string]interface{}
+	if err := json.Unmarshal(b, &jsonResp); err != nil {
+		fmt.Println(err.Error())
+		os.Exit(1)
+	}
 
-func init() {
-	pullTransifexCommand.Flags().StringSliceVarP(&languages, "languages", "l", nil, "languages")
-	pullTransifexCommand.MarkFlagRequired("languages")
+	var langs []string
+	for key := range jsonResp {
+		if key == "en" {
+			continue
+		}
+		langs = append(langs, key)
+	}
+
+	return langs
 }
 
 func pullCatalog(cmd *cobra.Command, args []string) {
+	languages := getLanguages()
+	fmt.Println("translations found:", languages)
+
 	folder := args[0]
 
 	for _, lang := range languages {