feat(stream_chat_localizations): Initial implementation

Signed-off-by: Sahil Kumar <[email protected]>

packages/stream_chat_flutter/lib/src/extension.dart

@@ -103,6 +103,12 @@ extension BuildContextX on BuildContext {
   // ignore: public_member_api_docs
   double get textScaleFactor =>
       MediaQuery.maybeOf(this)?.textScaleFactor ?? 1.0;
+
+  String translate({
+    required String key,
+    required String defaultValue,
+  }) =>
+      StreamChatLocalizations.of(this)?.translate(key) ?? defaultValue;
 }
 
 /// Extension on [BorderRadius]

packages/stream_chat_flutter/lib/src/stream_chat.dart

@@ -133,11 +133,6 @@ class StreamChatState extends State<StreamChat> {
   /// The current user as a stream
   Stream<User?> get userStream => widget.client.state.userStream;
 
-  @override
-  void initState() {
-    super.initState();
-  }
-
   @override
   void didChangeDependencies() {
     final locale = ui.window.locale;

packages/stream_chat_flutter/lib/src/stream_chat_localizations.dart

@@ -0,0 +1,97 @@
+import 'package:flutter/widgets.dart';
+
+// TODO : Fix localization instructions
+// ADDING A NEW STRING
+//
+// If you (someone contributing to the Stream Chat Flutter) want to add a new
+// string to the StreamChatLocalizations object (e.g. because you've added a new
+// widget and it has a tooltip), follow these steps:
+//
+// 1. Add the new getter to StreamChatLocalizations below.
+//
+// 2. Implement a default value in DefaultMaterialLocalizations below.
+//
+// 3. Add a test to test/material/localizations_test.dart that verifies that
+//    this new value is implemented.
+//
+// 4. Update the flutter_localizations package. To add a new string to the
+//    flutter_localizations package, you must first add it to the English
+//    translations (lib/src/l10n/en.json), including a description.
+//
+//    Then you need to add new entries for the string to all of the other
+//    language locale files by running:
+//    ```
+//    dart dev/tools/localization/bin/gen_missing_localizations.dart
+//    ```
+//    Which will copy the english strings into the other locales as placeholders
+//    until they can be translated.
+//
+//    Finally you need to re-generate lib/src/l10n/localizations.dart by running:
+//    ```
+//    dart dev/tools/localization/bin/gen_localizations.dart --overwrite
+//    ```
+//
+//    There is a README file with further information in the lib/src/l10n/
+//    directory.
+//
+// 5. If you are a Google employee, you should then also follow the instructions
+//    at go/flutter-l10n. If you're not, don't worry about it.
+//
+// UPDATING AN EXISTING STRING
+//
+// If you (someone contributing to the Flutter framework) want to modify an
+// existing string in the MaterialLocalizations objects, follow these steps:
+//
+// 1. Modify the default value of the relevant getter(s) in
+//    DefaultMaterialLocalizations below.
+//
+// 2. Update the flutter_localizations package. Modify the out-of-date English
+//    strings in lib/src/l10n/material_en.arb.
+//
+//    You also need to re-generate lib/src/l10n/localizations.dart by running:
+//    ```
+//    dart dev/tools/localization/bin/gen_localizations.dart --overwrite
+//    ```
+//
+//    This script may result in your updated getters being created in newer
+//    locales and set to the old value of the strings. This is to be expected.
+//    Leave them as they were generated, and they will be picked up for
+//    translation.
+//
+//    There is a README file with further information in the lib/src/l10n/
+//    directory.
+//
+// 3. If you are a Google employee, you should then also follow the instructions
+//    at go/flutter-l10n. If you're not, don't worry about it.
+
+/// Defines the localized resource values used by the StreamChatFlutter widgets.
+///
+/// See also:
+///
+///  * [GlobalStreamChatLocalizations], which provides material localizations
+///    for many languages.
+abstract class StreamChatLocalizations {
+  ///
+  String? translate(String key);
+
+  /// The `StreamChatLocalizations` from the closest [Localizations] instance
+  /// that encloses the given context.
+  ///
+  /// If no [StreamChatLocalizations] are available in the given `context`, this
+  /// method returns null.
+  ///
+  /// This method is just a convenient shorthand for:
+  /// `Localizations.of<StreamChatLocalizations>(context, StreamChatLocalizations)`.
+  ///
+  /// References to the localized resources defined by this class are typically
+  /// written in terms of this method. For example:
+  ///
+  /// ```dart
+  /// tooltip: StreamChatLocalizations.of(context).backButtonTooltip,
+  /// ```
+  static StreamChatLocalizations? of(BuildContext context) =>
+      Localizations.of<StreamChatLocalizations>(
+        context,
+        StreamChatLocalizations,
+      );
+}