feat(i18n): implements network data source

packages/wyatt_i18n/lib/src/core/exceptions/exceptions.dart

@@ -58,7 +58,13 @@ class MalformedValueException extends ClientException {
       : super('Key `$key` references a malformed value. ($value)');
 }
 
+/// Exception thrown when the parser fails.
 class ParserException extends ClientException {
   ParserException(String message, StackTrace? stackTrace)
       : super('$message\n\n$stackTrace');
 }
+
+/// Exception thrown when the i18n is not loaded.
+class NotLoadedException extends ClientException {
+  NotLoadedException() : super('I18n not loaded.');
+}

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/data/data_sources/network_data_source_impl.dart

@@ -14,21 +14,117 @@
 // 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 'package:flutter/services.dart';
+import 'package:http/http.dart' as http;
 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 network_data_source_impl}
+/// Implementation of [I18nDataSource] that loads i18n files from the network.
+///
+/// The [baseUri] is the base uri where the i18n files are located.
+/// The [baseName] is the name of the i18n files without the extension.
+/// The [fallbackAssetPath] is the path to the fallback i18n files.
+/// The [format] is the format of the i18n files.
+///
+/// For example, if the i18n files are located at `https://example.com/i18n/`
+/// and are named `i18n.en.arb`, `i18n.fr.arb`, etc., then the [baseUri] is
+/// `https://example.com/i18n/` and the [baseName] is `i18n` and the
+/// [format] is [Format.arb].
+///
+/// If the i18n file for the given locale is not found or if the fetch fails,
+/// then the fallback i18n files are loaded from the [fallbackAssetPath] in
+/// the root bundle.
+///
+/// For example, if the fallback i18n files are located in the `assets` and are
+/// named `i18n.arb`, `i18n.en.arb`, `i18n.fr.arb`, etc., then the
+/// [fallbackAssetPath] is `assets`.
+/// {@endtemplate}
 class NetworkDataSourceImpl extends I18nDataSource {
-  const NetworkDataSourceImpl({super.format = Format.arb}) : super();
-  
-  @override
-  Future<String> load({required String? locale}) {
-    // TODO(wyatt): implement load
-    throw UnimplementedError();
+  /// {@macro network_data_source_impl}
+  const NetworkDataSourceImpl({
+    required this.baseUri,
+    this.baseName = 'i18n',
+    this.fallbackAssetPath = 'assets',
+    super.format = Format.arb,
+    super.defaultLocale = 'en',
+  }) : super();
+
+  /// The base uri where the i18n files are located.
+  final Uri baseUri;
+
+  /// The name of the i18n files without the extension.
+  final String baseName;
+
+  /// The path to the fallback i18n files.
+  ///
+  /// This is used when the i18n file for the given locale is not found or
+  /// if the fetch fails.
+  final String fallbackAssetPath;
+
+  /// Tries to load the i18n file from the given [locale].
+  Future<String> _tryLoad(String? locale, {Uri? overrideUri}) async {
+    String? content;
+    final ext = format.name;
+
+    /// If the locale is null, then we try to load the default i18n file from
+    /// the fallback asset path.
+    /// Otherwise, we try to load the i18n file for the given locale from the
+    /// base uri.
+    final path = AssetsUtils.cleanPath(
+      locale == null
+          ? '$fallbackAssetPath/$baseName.$defaultLocale.$ext'
+          : overrideUri?.toString() ?? '$baseUri/$baseName.$locale.$ext',
+    );
+
+    if (locale == null) {
+      /// Load the default i18n file from the fallback asset path.
+      try {
+        if (await AssetsUtils.assetExists(path)) {
+          content = await rootBundle.loadString(path);
+        }
+      } catch (_) {
+        content = null;
+      }
+    } else {
+      /// Load the i18n file for the given locale from the base uri.
+      try {
+        final response = await http.get(Uri.parse(path));
+        if (response.statusCode >= 200 && response.statusCode < 300) {
+          content = response.body;
+        }
+      } catch (_) {
+        content = null;
+      }
+    }
+
+    /// If the i18n file is not found, then we try to load the
+    /// default i18n file.
+    if (content == null && locale != null) {
+      try {
+        final fallbackPath = AssetsUtils.cleanPath(
+          '$fallbackAssetPath/$baseName.$defaultLocale.$ext',
+        );
+        content = await rootBundle.loadString(fallbackPath);
+      } catch (_) {
+        throw SourceNotFoundException(path, format: format);
+      }
+    }
+
+    /// If the default i18n file is not found, then we throw an exception.
+    /// This case should happen only if the locale is null.
+    if (content == null) {
+      throw SourceNotFoundException(path, format: format);
+    }
+
+    return content;
   }
-  
+
   @override
-  Future<String> loadFrom(Uri uri) {
-    // TODO(wyatt): implement loadFrom
-    throw UnimplementedError();
-  }
+  Future<String> load({required String? locale}) async => _tryLoad(locale);
+
+  @override
+  Future<String> loadFrom(Uri uri) async => _tryLoad(null, overrideUri: uri);
 }

packages/wyatt_i18n/lib/src/data/repositories/i18n_repository_impl.dart

@@ -15,18 +15,27 @@
 // along with this program. If not, see <https://www.gnu.org/licenses/>.
 
 import 'package:wyatt_architecture/wyatt_architecture.dart';
-import 'package:wyatt_i18n/src/core/utils/i18n_parser.dart';
 import 'package:wyatt_i18n/wyatt_i18n.dart';
 import 'package:wyatt_type_utils/wyatt_type_utils.dart' hide Option;
 
+/// {@template i18n_repository_impl}
+/// The default implementation of [I18nRepository].
+/// {@endtemplate}
 class I18nRepositoryImpl extends I18nRepository {
+  /// {@macro i18n_repository_impl}
   I18nRepositoryImpl({
     required this.dataSource,
   }) : super();
 
+  /// The data source used to load the i18n file.
   final I18nDataSource dataSource;
+
+  /// The current i18n instance.
   I18n _i18n = const I18n.empty();
 
+  @override
+  I18n get i18n => _i18n;
+
   Future<I18n> _parse(
     String content,
     Parser<String, Map<String, dynamic>> parser, {
@@ -129,4 +138,19 @@ class I18nRepositoryImpl extends I18nRepository {
       throw KeyNotFoundException(key, arguments);
     }
   }
+
+  @override
+  Result<I18n, AppException> getI18n() =>
+      Result.conditional(!_i18n.isEmpty, _i18n, NotLoadedException());
+
+  @override
+  Result<String, AppException> getLocale() =>
+      Result.conditional(!_i18n.isEmpty, _i18n.locale, NotLoadedException());
+
+  @override
+  Result<void, AppException> setI18n(I18n i18n) {
+    _i18n = i18n;
+
+    return const Ok(null);
+  }
 }

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

@@ -17,23 +17,33 @@
 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.
   Future<String> load({required String? locale});
 
   /// Loads the i18n file from the source.
-  /// 
+  ///
   /// This method is used to load the i18n file from the given [Uri].
   Future<String> loadFrom(Uri uri);
 }

packages/wyatt_i18n/lib/src/domain/entities/i18n.dart

@@ -39,4 +39,6 @@ class I18n extends Entity {
   bool containsKey(String key) => data.containsKey(key);
 
   dynamic operator [](String key) => data[key];
+
+  bool get isEmpty => data.isEmpty && unparsedData.isEmpty && locale.isEmpty;
 }

packages/wyatt_i18n/lib/src/domain/repositories/i18n_repository.dart

@@ -19,10 +19,18 @@ import 'package:wyatt_i18n/src/core/utils/parser.dart';
 import 'package:wyatt_i18n/src/domain/entities/i18n.dart';
 import 'package:wyatt_type_utils/wyatt_type_utils.dart';
 
+/// {@template i18n_repository}
 /// Base class for i18n repositories.
+///
+/// This class is used to manage i18n files.
+/// {@endtemplate}
 abstract class I18nRepository extends BaseRepository {
+  /// {@macro i18n_repository}
   const I18nRepository() : super();
 
+  /// The current i18n file.
+  I18n get i18n;
+
   /// Loads the i18n file from the source.
   /// If [strict] is `true`, it will throw an NoLocaleException if the
   /// `@@locale` key is not found in the i18n file, otherwise it will
@@ -44,8 +52,26 @@ abstract class I18nRepository extends BaseRepository {
   });
 
   /// Gets the translation for the given [key].
+  ///
+  /// If [arguments] is not `null`, it will replace the placeholders in the
+  /// translation with the given arguments.
   Result<String, AppException> get(
     String key, [
     Map<String, dynamic> arguments = const {},
   ]);
+
+  /// Sets the current i18n instance.
+  ///
+  /// This method is used to set the current i18n instance.
+  Result<void, AppException> setI18n(I18n i18n);
+
+  /// Gets the current i18n instance.
+  ///
+  /// This method is used to get the current i18n instance.
+  Result<I18n, AppException> getI18n();
+
+  /// Gets the current locale.
+  ///
+  /// This method is used to get the current locale.
+  Result<String, AppException> getLocale();
 }

packages/wyatt_i18n/pubspec.yaml

@@ -9,6 +9,7 @@ environment:
 dependencies:
   collection: ^1.17.0
   flutter: {sdk: flutter}
+  http: ^0.13.5
   intl: ^0.18.0
   path: ^1.8.0
   petitparser: ^5.1.0