add rate limit, add already joined

assets/l10n/intl_en.arb

@@ -4086,6 +4086,7 @@
     }
   },
   "roomCapacityExplanation": "{roomType} capacity limits the number of non-admins allowed in a room.",
+  "tooManyRequest": "Too many request, please try again later.",
   "@roomCapacityExplanation": {
     "type": "text",
     "placeholders": {

lib/pangea/controllers/class_controller.dart

@@ -78,6 +78,13 @@ class ClassController extends BaseController {
         },
         body: jsonEncode({'access_code': classCode}),
       );
+      if (knockResponse.statusCode == 429) {
+        SpaceCodeUtil.messageSnack(
+          context,
+          L10n.of(context)!.tooManyRequest,
+        );
+        return;
+      }
       if (knockResponse.statusCode != 200) {
         SpaceCodeUtil.messageSnack(
           context,
@@ -87,6 +94,14 @@ class ClassController extends BaseController {
       }
       final knockResult = jsonDecode(knockResponse.body);
       final foundClasses = List<String>.from(knockResult['rooms']);
+      final alreadyJoined = List<String>.from(knockResult['already_joined']);
+      if (alreadyJoined.isNotEmpty) {
+        SpaceCodeUtil.messageSnack(
+          context,
+          L10n.of(context)!.alreadyInClass,
+        );
+        return;
+      }
       if (foundClasses.isEmpty) {
         SpaceCodeUtil.messageSnack(
           context,

lib/pangea/utils/space_code.dart

@@ -79,6 +79,7 @@ class SpaceCodeUtil {
       SnackBar(
         duration: const Duration(seconds: 10),
         content: Text(message),
+        showCloseIcon: true,
       ),
     );
   }