fix: add asynchronous translations #74

packages/clerk_auth/lib/src/clerk_auth/auth_error.dart

@@ -2,22 +2,14 @@
 ///
 class AuthError extends Error {
   /// Construct an [AuthError]
-  AuthError({this.code, required this.message, this.substitution});
+  AuthError({this.code, required this.message, this.messageSubstitutions});
 
   /// An error [code], likely to be an http status code
   final int? code;
 
   /// The associated [message]
   final String message;
 
-  /// A possible [substitution] within the message
-  final String? substitution;
-
-  @override
-  String toString() {
-    if (substitution case String substitution) {
-      return message.replaceAll('###', substitution);
-    }
-    return message;
-  }
+  /// A possible set of substitutions within the message
+  final List<String>? messageSubstitutions;
 }

packages/clerk_auth/lib/src/clerk_auth/http_client.dart

@@ -109,7 +109,7 @@ class DefaultHttpClient implements HttpClient {
       String ext when _imageExts.contains(ext) => MediaType('image', ext),
       String ext => throw AuthError(
           message: 'Unknown media type for upload: ###',
-          substitution: ext,
+          messageSubstitutions: [ext],
         ),
     };
   }

packages/clerk_auth/lib/src/models/enums.dart

@@ -143,7 +143,7 @@ enum Stage {
       Status.needsSecondFactor => second,
       _ => throw AuthError(
           message: 'No Stage for ###',
-          substitution: status.toString(),
+          messageSubstitutions: [status.toString()],
         ),
     };
   }

packages/clerk_auth/lib/src/models/strategy.dart

@@ -198,7 +198,7 @@ class Strategy {
       Field.emailAddress => Strategy.emailCode,
       _ => throw AuthError(
           message: 'No way to verify ###',
-          substitution: field.name,
+          messageSubstitutions: [field.name],
         ),
     };
   }

packages/clerk_flutter/README.md

@@ -71,6 +71,69 @@ class _ExampleAppState extends State<ExampleApp> {
 }
 ```
 
+## Translation
+
+The default language in use for alert and UI messaging within the Clerk Flutter SDK is English. For other languages, 
+you will need to override the `ClerkTranslator`  passed in to the `ClerkAuth` or `ClerkAuthProvider` widgets via the 
+optional `translator` parameter. Translations will need to be provided for the following (hopefully self-explanatory) 
+words and phrases:
+```text
+Add account
+Add email address
+Add phone number
+Already have an account?
+Authenticator app
+Backup code
+Cancel
+Click on the link that‘s been sent to ### and then check back here
+Continue
+Don’t have an account?
+Email address
+Email address '###' is invalid
+Email address verification
+Enter the code sent to ###
+Enter the code sent to you
+First name
+Last name
+Manage account
+OK
+Optional
+or
+Passkey
+Password
+Password and password confirmation must match
+Password confirmation
+Phone number
+Phone number '###' is invalid
+Phone number verification
+Phone numbers
+PRIMARY
+Profile
+Profile details
+Sign in
+Sign in by entering a code sent to you by email
+Sign in by entering a code sent to you by text message
+Sign in to ###
+Sign out
+Sign out of all accounts
+Sign up
+Sign up to ###
+Type '###' invalid
+UNVERIFIED
+Username
+Verify your email address
+Verify your phone number
+Web3 wallet
+Welcome back! Please sign in to continue
+Welcome! Please fill in the details to get started
+```
+
+
+### Asynchronous translation
+Some translations cannot be known ahead of time e.g. arbitrary error messages from the Clerk server. An 
+asynchronous translation method `translateAsync` is provided to allow for translation generation on the fly in this 
+instance.
+
 ## License
 
 This SDK is licensed under the MIT license found in the [LICENSE](./LICENSE) file.

packages/clerk_flutter/lib/src/utils/clerk_translator.dart

@@ -5,33 +5,45 @@ abstract class ClerkTranslator {
   const ClerkTranslator();
 
   /// the character sequence to replace with [substitution] during
-  /// a call to [translate]
-  final substitutionKey = '###';
+  /// a call to [translate]. By default this is `###` for the first item
+  /// (index 0) and `#<index + 1>#` for subsequent indices (index 1 or more)
+  ///
+  String substitutionKey([int idx = 0]) => idx < 1 ? '###' : '#${idx + 1}#';
 
   /// Translate a [phrase]] into a different language. Identity function by default
   /// for English
   ///
   /// A [substitution] or multiple [substitutions] for keys inside the [phrase]:
   ///
-  /// if a single [substitution] is present, replace the first instance of
-  /// [substitutionKey] (default `###`) with it
+  /// If a single [substitution] is present, replace the first instance of
+  /// `substitutionKey()` with it
   ///
-  /// if multiple [substitutions] are present, replace the first found character sequences `#<n>#`
-  /// with each substitution where [n] is the 1-based index into the array.
+  /// If multiple [substitutions] are present, use each substitution to
+  /// replace the first found appropriate character sequence:
+  /// `substitutionKey(index)`
   ///
-  /// This allows word order to vary across different languages without having to manipulate the
-  /// [substitutions] array, viz:
+  /// This allows word order to vary across different languages without having
+  /// to manipulate the [substitutions] array, viz:
   ///
-  /// `translate('#1# bites #2#', substitutions: ['man', 'dog'])`
+  /// `translate('### bites #2#', substitutions: ['man', 'dog'])`
   /// vs
-  /// `translate('#2# is bitten by #1#', substitutions: ['man', 'dog'])`
+  /// `translate('#2# is bitten by ###', substitutions: ['man', 'dog'])`
   ///
   String translate(
     String phrase, {
     String? substitution,
     List<String> substitutions = const [],
   });
 
+  /// An asynchronous version of [translate], for situations in which the
+  /// translation might not immediately be to hand. Parameters as above.
+  ///
+  Future<String> translateAsync(
+    String phrase, {
+    String? substitution,
+    List<String>? substitutions,
+  });
+
   /// A method that takes a list of [items] e.g. \['first', 'second', 'third'\]
   /// and returns a textual representation of its contents as alternatives
   /// e.g. "first, second or third"
@@ -55,19 +67,37 @@ class DefaultClerkTranslator extends ClerkTranslator {
   const DefaultClerkTranslator();
 
   @override
-  String translate(String phrase,
-      {String? substitution, List<String> substitutions = const []}) {
+  String translate(
+    String phrase, {
+    String? substitution,
+    List<String>? substitutions,
+  }) {
     if (substitution case String sub) {
-      return phrase.replaceFirst(substitutionKey, sub);
+      return phrase.replaceFirst(substitutionKey(), sub);
     }
 
-    for (int i = 0; i < substitutions.length; ++i) {
-      phrase = phrase.replaceFirst('#${i + 1}#', substitutions[i]);
+    if (substitutions case List<String> substitutions) {
+      for (int i = 0; i < substitutions.length; ++i) {
+        phrase = phrase.replaceFirst(substitutionKey(i), substitutions[i]);
+      }
     }
 
     return phrase;
   }
 
+  @override
+  Future<String> translateAsync(
+    String phrase, {
+    String? substitution,
+    List<String>? substitutions,
+  }) async {
+    return translate(
+      phrase,
+      substitution: substitution,
+      substitutions: substitutions,
+    );
+  }
+
   @override
   String alternatives(List<String> items,
       {String connector = 'or', String? prefix}) {

packages/clerk_flutter/lib/src/widgets/authentication/clerk_sign_out_panel.dart

@@ -15,7 +15,7 @@ class ClerkSignOutPanel extends StatelessWidget {
       padding: horizontalPadding16,
       child: ClerkMaterialButton(
         onPressed: () => auth.signOut(),
-        label: Text(auth.translator.translate('Sign Out')),
+        label: Text(auth.translator.translate('Sign out')),
       ),
     );
   }

packages/clerk_flutter/lib/src/widgets/authentication/clerk_sign_up_panel.dart

@@ -74,7 +74,7 @@ class _ClerkSignUpPanelState extends State<ClerkSignUpPanel> {
               key: const Key('phone_code'),
               title: translator.translate('Verify your phone number'),
               subtitle: translator.translate(
-                'Enter code sent to ###',
+                'Enter the code sent to ###',
                 substitution: _values[clerk.UserAttribute.phoneNumber],
               ),
               onSubmit: (code) async {
@@ -96,7 +96,7 @@ class _ClerkSignUpPanelState extends State<ClerkSignUpPanel> {
               key: const Key('email_code'),
               title: translator.translate('Verify your email address'),
               subtitle: translator.translate(
-                'Enter code sent to ###',
+                'Enter the code sent to ###',
                 substitution: _values[clerk.UserAttribute.emailAddress],
               ),
               onSubmit: (code) async {

packages/clerk_flutter/lib/src/widgets/control/clerk_auth_provider.dart

@@ -149,8 +149,9 @@ class ClerkAuthProvider extends clerk.Auth with ChangeNotifier {
   /// but may still not be acceptable to the back end
   String? checkPassword(String? password, String? confirmation) {
     if (password != confirmation) {
-      return translator
-          .translate('Password and password confirmation must match');
+      return translator.translate(
+        'Password and password confirmation must match',
+      );
     }
 
     if (password case String password when password.isNotEmpty) {

packages/clerk_flutter/lib/src/widgets/ui/clerk_error_listener.dart

@@ -32,25 +32,28 @@ class ClerkErrorListener extends StatefulWidget {
   static Future<void> defaultErrorHandler(
       BuildContext context, AuthError error) async {
     final translator = ClerkAuth.translatorOf(context);
-    ScaffoldMessenger.of(context).showSnackBar(
-      SnackBar(
-        shape: const RoundedRectangleBorder(
-          borderRadius: BorderRadius.only(
-            topLeft: Radius.circular(12.0),
-            topRight: Radius.circular(12.0),
-          ),
-        ),
-        content: Text(
-          translator.translate(
-            error.message,
-            substitution: error.substitution,
+    final message = await translator.translateAsync(
+      error.message,
+      substitutions: error.messageSubstitutions,
+    );
+    if (context.mounted) {
+      ScaffoldMessenger.of(context).showSnackBar(
+        SnackBar(
+          shape: const RoundedRectangleBorder(
+            borderRadius: BorderRadius.only(
+              topLeft: Radius.circular(12.0),
+              topRight: Radius.circular(12.0),
+            ),
           ),
-          style: ClerkTextStyle.subtitle.copyWith(
-            color: ClerkColors.white,
+          content: Text(
+            message,
+            style: ClerkTextStyle.subtitle.copyWith(
+              color: ClerkColors.white,
+            ),
           ),
         ),
-      ),
-    );
+      );
+    }
   }
 
   @override

packages/clerk_flutter/lib/src/widgets/user/clerk_user_profile.dart

@@ -27,7 +27,7 @@ class ClerkUserProfile extends StatelessWidget {
         default:
           throw clerk.AuthError(
             message: "Type '###' invalid",
-            substitution: type.name,
+            messageSubstitutions: [type.name],
           );
       }
     }
@@ -92,7 +92,7 @@ class ClerkUserProfile extends StatelessWidget {
           ),
         _ => throw clerk.AuthError(
             message: "Type '###' invalid",
-            substitution: type.name,
+            messageSubstitutions: [type.name],
           ),
       },
     );
@@ -108,7 +108,7 @@ class ClerkUserProfile extends StatelessWidget {
       } else {
         throw clerk.AuthError(
           message: "$title '###' is invalid",
-          substitution: identifier,
+          messageSubstitutions: [identifier],
         );
       }
     }