fix : refresh token Completer in app_interceptor

packages/core/lib/infrastructure/remote/app_interceptor.dart

@@ -4,46 +4,56 @@ import '../../core.dart';
 typedef RefreshTokenCallback = Future<String?> Function();
 class AppInterceptor extends Interceptor {
   final RefreshTokenCallback refreshTokenCallback;
+  Completer<String?>? _refreshCompleter;
 
   AppInterceptor({required this.refreshTokenCallback});
 
+
   @override
   Future<void> onError(DioException err, ErrorInterceptorHandler handler) async {
     if (err.response?.statusCode == 401 && !ApiHandler.isRefreshing) {
-
       ApiHandler.cancelAllRequests("Token expired - refreshing");
 
-      ApiHandler.isRefreshing = true;
+      if (_refreshCompleter == null) {
+        _refreshCompleter = Completer<String?>();
+        ApiHandler.isRefreshing = true;
+
+        try {
+          final newToken = await refreshTokenCallback();
+          if (newToken == null) throw Exception("Refresh failed");
+
+          ApiHandler.reset();
+          _refreshCompleter?.complete(newToken);
+        } catch (e) {
+          _refreshCompleter?.completeError(e);
+          if (!ApiHandler.isRedirecting) {
+            ApiHandler.isRedirecting = true;
+            ApiHandler.cancelAllRequests("Cancel All Requests - Unauthorized");
+            if (Get.currentRoute != '/Auth') {
+              Get.offAllNamed('/Auth');
+            }
+          }
+        } finally {
+          ApiHandler.isRefreshing = false;
+          _refreshCompleter = null;
+        }
+      }
 
       try {
-        final newToken = await refreshTokenCallback();
-        if (newToken == null) throw Exception("Refresh failed");
+        final newToken = await _refreshCompleter!.future;
+        if (newToken != null) {
+          final opts = err.requestOptions;
+          opts.headers['Authorization'] = 'Bearer $newToken';
 
-
-        ApiHandler.reset();
-
-        final opts = err.requestOptions;
-        opts.headers['Authorization'] = 'Bearer $newToken';
-
-
-        final dio = Dio();
-        final cloneReq = await dio.fetch(opts);
-        handler.resolve(cloneReq);
-        return;
-      } catch (e) {
-        if (!ApiHandler.isRedirecting) {
-          ApiHandler.isRedirecting = true;
-          ApiHandler.cancelAllRequests("Cancel All Requests - Unauthorized");
-          if (Get.currentRoute !=  '/Auth') {
-            Get.offAllNamed('/Auth');
-          }
+          final dio = Dio();
+          final cloneReq = await dio.fetch(opts);
+          handler.resolve(cloneReq);
+          return;
         }
+      } catch (_) {
         handler.reject(err);
-      } finally {
-        ApiHandler.isRefreshing = false;
       }
     } else if (err.type == DioExceptionType.cancel) {
-
       handler.next(err);
     } else {
       handler.next(err);