packages/wyatt_architecture/lib/src/domain/usecases/usecase.dart

@@ -14,14 +14,70 @@
 // 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:async';
+
 import 'package:wyatt_architecture/src/core/exceptions/exceptions.dart';
+import 'package:wyatt_architecture/src/domain/usecases/observers.dart';
 import 'package:wyatt_type_utils/wyatt_type_utils.dart';
 
-typedef FutureResult<T> = Future<Result<T, AppException>>;
+typedef FutureOrResult<T> = FutureOr<Result<T, AppException>>;
 typedef StreamResult<T> = Stream<Result<T, AppException>>;
-typedef Res<T> = Result<T, AppException>;
 
-// ignore: one_member_abstracts
+/// Abstract class of a use case
-abstract class UseCase<Parameters, ReturnType> {
+abstract class BaseUseCase<Parameters, ReturnType> {
-  FutureResult<ReturnType> call(Parameters params);
+  /// Run use case scenarios
+  ReturnType execute(Parameters parameters);
+
+  /// Private function to implement main scenario
+  /// of your usecase.
+  ReturnType call(Parameters params);
+}
+
+/// Abstract class of a use case that deals specifically
+/// with the response and its state.
+abstract class UseCase<Parameters, ReturnType>
+    extends BaseUseCase<Parameters?, FutureOrResult<ReturnType>>
+    with Observer<Parameters, ReturnType> {
+  FutureOr<void> _onSuccess(ReturnType data);
+
+  /// Supports the result of the main scenario and integrates
+  /// some alternative scenarios if necessary.
+  @override
+  FutureOrResult<ReturnType> execute(Parameters? parameters) =>
+      Result.tryCatchAsync(
+        () async {
+          await onStart(parameters);
+          final response = await call(parameters);
+          if (response.isErr) {
+            await onError(response.err);
+          } else if (response.isOk && response.ok != null) {
+            await _onSuccess(response.ok as ReturnType);
+          }
+
+          return response.ok!;
+        },
+        (error) => ClientException(
+          error.toString(),
+        ),
+      );
+}
+
+/// Abtstract classic usecase.
+abstract class AsyncUseCase<Parameters, ReturnType>
+    extends UseCase<Parameters?, ReturnType> with AsyncObserver<ReturnType> {
+  @override
+  FutureOr<void> _onSuccess(ReturnType data) => onComplete(data);
+}
+
+/// Abstract specific usecase bases on streams
+abstract class StreamUseCase<Parameters, ReturnType>
+    extends UseCase<Parameters?, Stream<ReturnType>>
+    with StreamObserver<ReturnType> {
+  @override
+  FutureOr<void> _onSuccess(Stream<ReturnType> data) {
+    data.listen(
+      onData,
+      onDone: onDone,
+    );
+  }
 }