feat(i18n): add default locale

packages/wyatt_i18n/lib/src/core/utils/assets_utils.dart

@@ -0,0 +1,40 @@
+// Copyright (C) 2023 WYATT GROUP
+// Please see the AUTHORS file for details.
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <https://www.gnu.org/licenses/>.
+
+import 'dart:convert';
+
+import 'package:flutter/services.dart';
+
+class AssetsUtils {
+  /// Checks if the given [assetPath] is a local asset.
+  ///
+  /// In fact, this method loads the asset and checks if it is null.
+  static Future<bool> assetExists(String assetPath) async {
+    final encoded = utf8.encoder.convert(
+      Uri(path: Uri.encodeFull(assetPath)).path,
+    );
+    final asset = await ServicesBinding.instance.defaultBinaryMessenger
+        .send('flutter/assets', encoded.buffer.asByteData());
+
+    return asset != null;
+  }
+
+  /// Cleans the given [path] by removing all the consecutive slashes.
+  /// For example, `///a///b///c///` becomes `/a/b/c/`.
+  /// It also removes the first slash if it exists.
+  static String cleanPath(String path) =>
+      path.replaceAll(RegExp(r'\/+'), '/').replaceFirst(RegExp(r'^\/'), '');
+}

packages/wyatt_i18n/lib/src/data/data_sources/assets_file_data_source_impl.dart

@@ -14,11 +14,10 @@
 // You should have received a copy of the GNU General Public License
 // along with this program. If not, see <https://www.gnu.org/licenses/>.
 
-import 'dart:convert';
-
-import 'package:flutter/services.dart' show ServicesBinding, rootBundle;
+import 'package:flutter/services.dart' show AssetBundle, rootBundle;
 import 'package:wyatt_i18n/src/core/enums/format.dart';
 import 'package:wyatt_i18n/src/core/exceptions/exceptions.dart';
+import 'package:wyatt_i18n/src/core/utils/assets_utils.dart';
 import 'package:wyatt_i18n/src/domain/data_sources/i18n_data_source.dart';
 
 /// {@template assets_file_data_source_impl}
@@ -34,10 +33,11 @@ import 'package:wyatt_i18n/src/domain/data_sources/i18n_data_source.dart';
 /// {@endtemplate}
 class AssetsFileDataSourceImpl extends I18nDataSource {
   /// {@macro assets_file_data_source_impl}
-  const AssetsFileDataSourceImpl({
+  AssetsFileDataSourceImpl({
     this.basePath = 'assets',
     this.baseName = 'i18n',
     super.format = Format.arb,
+    super.defaultLocale = 'en',
   }) : super();
 
   /// The folder where the i18n files are located.
@@ -46,29 +46,23 @@ class AssetsFileDataSourceImpl extends I18nDataSource {
   /// The name of the i18n files without the extension.
   final String baseName;
 
-  /// Checks if the given [assetPath] is a local asset.
-  ///
-  /// In fact, this method loads the asset and checks if it is null.
-  Future<bool> assetExists(String assetPath) async {
-    final encoded = utf8.encoder.convert(
-      Uri(path: Uri.encodeFull(assetPath)).path,
-    );
-    final asset = await ServicesBinding.instance.defaultBinaryMessenger
-        .send('flutter/assets', encoded.buffer.asByteData());
-
-    return asset != null;
-  }
+  /// The asset bundle used to load the i18n files.
+  final AssetBundle assetBundle = rootBundle;
 
   /// Tries to load the i18n file from the given [locale].
   Future<String> _tryLoad(String? locale) async {
     String? content;
     final ext = format.name;
-    final path = locale == null
-        ? '$basePath/$baseName.$ext'
-        : '$basePath/$baseName.$locale.$ext';
+
+    final path = AssetsUtils.cleanPath(
+      locale == null
+          ? '$basePath/$baseName.$defaultLocale.$ext'
+          : '$basePath/$baseName.$locale.$ext',
+    );
+
     try {
-      if (await assetExists(path)) {
-        content = await rootBundle.loadString(path);
+      if (await AssetsUtils.assetExists(path)) {
+        content = await assetBundle.loadString(path);
       }
     } catch (_) {
       content = null;
@@ -78,7 +72,10 @@ class AssetsFileDataSourceImpl extends I18nDataSource {
     /// default i18n file.
     if (content == null && locale != null) {
       try {
-        content = await rootBundle.loadString('$basePath/$baseName.$ext');
+        final fallbackPath = AssetsUtils.cleanPath(
+          '$basePath/$baseName.$defaultLocale.$ext',
+        );
+        content = await assetBundle.loadString(fallbackPath);
       } catch (_) {
         throw SourceNotFoundException(path, format: format);
       }
@@ -98,7 +95,7 @@ class AssetsFileDataSourceImpl extends I18nDataSource {
   Future<String> _tryLoadUri(Uri uri) async {
     String? content;
     try {
-      content = await rootBundle.loadString(uri.toString());
+      content = await assetBundle.loadString(uri.toString());
     } catch (_) {
       throw SourceNotFoundException(uri.toString(), format: format);
     }

packages/wyatt_i18n/lib/src/domain/data_sources/i18n_data_source.dart

@@ -17,16 +17,26 @@
 import 'package:wyatt_architecture/wyatt_architecture.dart';
 import 'package:wyatt_i18n/src/core/enums/format.dart';
 
+/// {@template i18n_data_source}
 /// Base class for i18n data sources.
 ///
 /// This class is used to load i18n files from a source.
 /// It returns a [Future] that resolves to a [String] containing the i18n file
 /// contents.
+/// {@endtemplate}
 abstract class I18nDataSource extends BaseDataSource {
-  const I18nDataSource({this.format = Format.arb});
+  /// {@macro i18n_data_source}
+  const I18nDataSource({
+    this.format = Format.arb,
+    this.defaultLocale = 'en',
+  });
 
+  /// The format of the i18n file.
   final Format format;
 
+  /// The default locale.
+  final String defaultLocale;
+
   /// Loads the i18n file from the source.
   /// If [locale] is not `null`, it will load the file with the given [locale].
   /// Otherwise, it will load the file from the default location.