Implement translations system

lib/utils/intl_utils.dart

@@ -1,7 +1,32 @@
+import 'dart:convert';
+
+import 'package:flutter/services.dart';
+import 'package:intl/intl_standalone.dart';
+
 /// Internationalization utilities
 ///
 /// @author Pierre HUBERT
 
+String _currLang;
+Map<String, Map<String, String>> translations;
+
+/// Initialize translations system
+///
+/// This method currently fetch the current user language
+Future<void> initTranslations() async {
+  _currLang = await findSystemLocale();
+
+  // Load the list of translations
+  final list = Map<String, String>.from(
+      jsonDecode(await rootBundle.loadString("assets/langs.json")));
+
+  translations = new Map();
+  for (final entry in list.entries) {
+    translations[entry.key] = Map<String, String>.from(jsonDecode(
+        await rootBundle.loadString("assets/langs/${entry.value}.json")));
+  }
+}
+
 /// Translate a string
 ///
 /// Translate a given [string] into the current language, if available
@@ -9,10 +34,14 @@
 /// Then apply the list of [args] to the string, each argument name is
 /// surrounded by '%'
 String tr(String string, {Map<String, String> args}) {
-  //TODO : create translation system
+  // Check if a translation is available
+  if (_currLang != null &&
+      translations.containsKey(_currLang) &&
+      translations[_currLang].containsKey(string))
+    string = translations[_currLang][string];
 
   //Apply arguments
-  if(args != null)
+  if (args != null)
     args.forEach((key, value) => string = string.replaceAll("%$key%", value));
 
   return string;