feat(*): Migrate to explicit exceptions: part 1

Explicit exceptions in authentication repository.

lib/exceptions/exceptions.dart

@@ -1,13 +1,63 @@
+import 'dart:async';
+
 import 'package:dart_mappable/dart_mappable.dart';
+import 'package:fpdart/fpdart.dart';
 
 part 'exceptions.mapper.dart';
 
+/// App wide wrapped exception
+typedef SyncEither<T> = Either<AppException, T>;
+
+/// App wide wrapped exception for future.
+typedef AsyncEither<T> = TaskEither<AppException, T>;
+
+/// App wide wrapped exception with void as value.
+typedef SyncVoidEither = Either<AppException, void>;
+
+/// App wide wrapped exception for future with void as value.
+typedef AsyncVoidEither = TaskEither<AppException, void>;
+
+/// Convenient `right(null)`
+Either<L, void> rightVoid<L>() => Right<L, void>(null);
+
+/// Functional programming operators on [AsyncEither] with generic type [T].
+extension FPFutureExt<T> on AsyncEither<T> {
+  /// Await and handle result.
+  Future<void> handle(
+    FutureOr<void> Function(AppException e) onLeft,
+    FutureOr<void> Function(T v) onRight,
+  ) async {
+    switch (await run()) {
+      case Left(:final value):
+        onLeft(value);
+      case Right(:final value):
+        onRight(value);
+    }
+  }
+}
+
+/// Base class for all exceptions.
+@MappableClass()
+sealed class AppException with AppExceptionMappable implements Exception {
+  AppException({
+    this.message,
+  }) : stackTrace = StackTrace.current;
+
+  /// Message to print
+  final String? message;
+
+  /// Collected stack trace.
+  late final StackTrace stackTrace;
+}
+
 /// Exception represents an error occurred in http request.
 ///
 /// Usually the response status code is not 200.
-class HttpRequestFailedException implements Exception {
+@MappableClass()
+final class HttpRequestFailedException extends AppException
+    with HttpRequestFailedExceptionMappable {
   /// Constructor.
-  const HttpRequestFailedException(this.statusCode);
+  HttpRequestFailedException(this.statusCode);
 
   /// Returned status code.
   final int? statusCode;
@@ -21,25 +71,75 @@ class HttpRequestFailedException implements Exception {
 /// Till now we manually set the status code to 999 to indicate this error, but
 /// it should be refactored to a more proper way.
 @MappableClass()
-class HttpHandshakeFailedException
-    with HttpHandshakeFailedExceptionMappable
-    implements Exception {
+final class HttpHandshakeFailedException extends AppException
+    with HttpHandshakeFailedExceptionMappable {
   /// Constructor.
-  const HttpHandshakeFailedException(this.message);
-
-  /// Error message.
-  final String message;
+  HttpHandshakeFailedException(String message) : super(message: message);
 }
 
-/// Invalid setting's key (aka name) when accessing settings values:
-/// setting values or getting values.
+/// The form hash used in login progress is not found.
 @MappableClass()
-class InvalidSettingsKeyException
-    with InvalidSettingsKeyExceptionMappable
-    implements Exception {
-  /// Constructor.
-  const InvalidSettingsKeyException(this.message);
+final class LoginFormHashNotFoundException extends AppException
+    with LoginFormHashNotFoundExceptionMappable {}
+
+/// Found form hash, but it's not in the expect format.
+@MappableClass()
+final class LoginInvalidFormHashException extends AppException
+    with LoginInvalidFormHashExceptionMappable {}
+
+/// The login result message of login progress is not found.
+///
+/// Indicating that we do not know whether we logged in successful or not.
+@MappableClass()
+final class LoginMessageNotFoundException extends AppException
+    with LoginMessageNotFoundExceptionMappable {}
+
+/// The captcha user texted is incorrect.
+@MappableClass()
+final class LoginIncorrectCaptchaException extends AppException
+    with LoginIncorrectCaptchaExceptionMappable {}
+
+/// Incorrect password or account.
+@MappableClass()
+final class LoginInvalidCredentialException extends AppException
+    with LoginInvalidCredentialExceptionMappable {}
+
+/// Security question or its answer is incorrect.
+@MappableClass()
+final class LoginIncorrectSecurityQuestionException extends AppException
+    with LoginIncorrectSecurityQuestionExceptionMappable {}
+
+/// Reached the limit of login attempt.
+///
+/// Maybe locked in 20 minutes.
+@MappableClass()
+final class LoginAttemptLimitException extends AppException
+    with LoginAttemptLimitExceptionMappable {}
 
-  /// Error message.
-  final String message;
+/// User info not found when try to login after login seems success.
+///
+/// Now we should update the logged user info but this exception means we can
+/// not found the logged user info.
+@MappableClass()
+final class LoginUserInfoNotFoundException extends AppException
+    with LoginUserInfoNotFoundExceptionMappable {}
+
+/// Some other exception that not recognized.
+@MappableClass()
+final class LoginOtherErrorException extends AppException
+    with LoginOtherErrorExceptionMappable {
+  /// Constructor.
+  LoginOtherErrorException(String message) : super(message: message);
 }
+
+/// The form hash used to logout is not found.
+@MappableClass()
+final class LogoutFormHashNotFoundException extends AppException
+    with LogoutFormHashNotFoundExceptionMappable {}
+
+/// Failed to logout.
+///
+/// Nearly impossible to happen.
+@MappableClass()
+final class LogoutFailedException extends AppException
+    with LogoutFailedExceptionMappable {}

lib/features/authentication/bloc/authentication_bloc.dart

@@ -2,7 +2,6 @@ import 'package:dart_mappable/dart_mappable.dart';
 import 'package:flutter_bloc/flutter_bloc.dart';
 import 'package:tsdm_client/exceptions/exceptions.dart';
 import 'package:tsdm_client/features/authentication/repository/authentication_repository.dart';
-import 'package:tsdm_client/features/authentication/repository/exceptions/exceptions.dart';
 import 'package:tsdm_client/features/authentication/repository/models/models.dart';
 import 'package:tsdm_client/utils/logger.dart';
 
@@ -11,7 +10,7 @@ part 'authentication_event.dart';
 part 'authentication_state.dart';
 
 /// Emitter
-typedef AuthenticationEmitter = Emitter<AuthenticationState>;
+typedef _Emitter = Emitter<AuthenticationState>;
 
 /// Bloc the authentication, including login and logout.
 ///
@@ -23,60 +22,45 @@ class AuthenticationBloc extends Bloc<AuthenticationEvent, AuthenticationState>
     required AuthenticationRepository authenticationRepository,
   })  : _authenticationRepository = authenticationRepository,
         super(const AuthenticationState()) {
-    on<AuthenticationFetchLoginHashRequested>(
-      _onAuthenticationFetchLoginHashRequested,
+    on<AuthenticationEvent>(
+      (event, emitter) => switch (event) {
+        AuthenticationFetchLoginHashRequested() =>
+          _onFetchLoginHashRequested(emitter),
+        AuthenticationLoginRequested(:final userCredential) =>
+          _onLoginRequested(emitter, userCredential),
+      },
     );
-    on<AuthenticationLoginRequested>(_onAuthenticationLoginRequested);
   }
 
   final AuthenticationRepository _authenticationRepository;
 
-  Future<void> _onAuthenticationFetchLoginHashRequested(
-    AuthenticationFetchLoginHashRequested event,
-    AuthenticationEmitter emit,
-  ) async {
+  Future<void> _onFetchLoginHashRequested(_Emitter emit) async {
     emit(state.copyWith(status: AuthenticationStatus.fetchingHash));
-    try {
-      final loginHash = await _authenticationRepository.fetchHash();
-      emit(
+    await _authenticationRepository.fetchHash().match(
+      (e) {
+        handle(e);
+        emit(state.copyWith(status: AuthenticationStatus.failure));
+      },
+      (v) => emit(
         state.copyWith(
           status: AuthenticationStatus.gotHash,
-          loginHash: loginHash,
-        ),
-      );
-    } on HttpRequestFailedException catch (e) {
-      debug('failed to fetch login hash: $e');
-      emit(state.copyWith(status: AuthenticationStatus.failure));
-    } on LoginException catch (e) {
-      debug('failed to fetch login hash: $e');
-      emit(
-        state.copyWith(
-          status: AuthenticationStatus.failure,
-          loginException: e,
+          loginHash: v,
         ),
-      );
-    }
+      ),
+    ).run();
   }
 
-  Future<void> _onAuthenticationLoginRequested(
-    AuthenticationLoginRequested event,
-    AuthenticationEmitter emit,
+  Future<void> _onLoginRequested(
+    _Emitter emit,
+    UserCredential userCredential,
   ) async {
     emit(state.copyWith(status: AuthenticationStatus.loggingIn));
-    try {
-      await _authenticationRepository.loginWithPassword(event.userCredential);
-      emit(state.copyWith(status: AuthenticationStatus.success));
-    } on HttpRequestFailedException catch (e) {
-      debug('failed to login: $e');
-      emit(state.copyWith(status: AuthenticationStatus.failure));
-    } on LoginException catch (e) {
-      debug('failed to login: $e');
-      emit(
-        state.copyWith(
-          status: AuthenticationStatus.failure,
-          loginException: e,
-        ),
-      );
-    }
+    await _authenticationRepository.loginWithPassword(userCredential).match(
+      (e) {
+        handle(e);
+        emit(state.copyWith(status: AuthenticationStatus.failure));
+      },
+      (_) => emit(state.copyWith(status: AuthenticationStatus.success)),
+    ).run();
   }
 }

lib/features/authentication/bloc/authentication_state.dart

@@ -42,5 +42,5 @@ final class AuthenticationState with AuthenticationStateMappable {
   final LoginHash? loginHash;
 
   /// Exception happened in login.
-  final LoginException? loginException;
+  final AppException? loginException;
 }