Added Auto-route language support for documentation.

res/app/components/stf/language/language-service.js

@@ -0,0 +1,47 @@
+var supportedLanguages = require('./../../../../common/lang/langs.json')
+
+module.exports = function LanguageServiceFactory(
+  SettingsService
+, gettextCatalog
+) {
+  // TODO: make this LanguageProvider so it can be used on config
+
+  var LanguageService = {}
+
+  function detectLanguage() {
+    return (navigator.language || navigator.userLanguage || 'en-US')
+      .substring(0, 2)
+  }
+
+  function isSupported(lang) {
+    return !!supportedLanguages[lang]
+  }
+
+  function onlySupported(lang, defaultValue) {
+    return isSupported(lang) ? lang : defaultValue
+  }
+
+  LanguageService.settingKey = 'selectedLanguage'
+  LanguageService.supportedLanguages = supportedLanguages
+  LanguageService.defaultLanguage = 'en'
+  LanguageService.detectedLanguage =
+    onlySupported(detectLanguage(), LanguageService.defaultLanguage)
+
+  SettingsService.sync(
+    LanguageService
+  , {
+      target: LanguageService.settingKey
+    , source: LanguageService.settingKey
+    , defaultValue: LanguageService.detectedLanguage
+    }
+  , updateLanguage
+  )
+
+  function updateLanguage() {
+    gettextCatalog.setCurrentLanguage(LanguageService.selectedLanguage)
+  }
+
+  LanguageService.updateLanguage = updateLanguage
+
+  return LanguageService
+}