feat(form): add list option validator

packages/wyatt_form_bloc/lib/src/cubit/form_data_cubit.dart

@@ -23,16 +23,16 @@ import 'package:wyatt_form_bloc/src/form/form.dart';
 
 part 'form_data_state.dart';
 
-class FormDataCubit extends Cubit<FormDataState> {
-  final Future<bool> Function(FormDataState state)? _onSubmit;
+abstract class FormDataCubit extends Cubit<FormDataState> {
+  FormDataCubit({required FormData entries})
+      : super(FormDataState(data: entries));
 
-  FormDataCubit({
-    required FormData entries,
-    Future<bool> Function(FormDataState state)? onSubmit,
-  })  : _onSubmit = onSubmit,
-        super(FormDataState(data: entries));
-
-  void dataChanged<T>(String field, FormInput dirtyValue) {
+  /// Change value of a field.
+  /// 
+  /// Inputs:
+  /// - `field`: The key of the field to change.
+  /// - `dirtyValue`: The new value of the field.
+  void dataChanged(String field, FormInput dirtyValue) {
     final _form = state.data.clone();
 
     if (_form.contains(field)) {
@@ -49,6 +49,11 @@ class FormDataCubit extends Cubit<FormDataState> {
     );
   }
 
+  /// Update entries list.
+  /// 
+  /// Inputs:
+  /// - `data`: The new entries list.
+  /// - `operation`: The operation to perform on the entries set.
   void updateFormData(
     FormData data, {
     SetOperation operation = SetOperation.replace,
@@ -78,13 +83,6 @@ class FormDataCubit extends Cubit<FormDataState> {
     );
   }
 
-  Future<void> submitForm() async {
-    unawaited(
-      _onSubmit?.call(state).then((bool reemit) {
-        if (reemit) {
-          emit(state);
-        }
-      }),
-    );
-  }
+  /// Submit the form.
+  Future<void> submitForm();
 }

packages/wyatt_form_bloc/lib/src/validators/list_option.dart

@@ -0,0 +1,48 @@
+// Copyright (C) 2022 WYATT GROUP
+// Please see the AUTHORS file for details.
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// 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 'package:wyatt_form_bloc/src/enums/enums.dart';
+import 'package:wyatt_form_bloc/src/form/form.dart';
+
+/// {@template list_option}
+/// Form input for a list input
+/// {@endtemplate}
+class ListOption<T> extends FormInput<List<T>, ValidationError> {
+  /// {@macro list_option}
+  const ListOption.pure({List<T>? defaultValue})
+      : super.pure(defaultValue ?? const []);
+
+  /// {@macro list_option}
+  const ListOption.dirty({List<T>? value}) : super.dirty(value ?? const []);
+
+  ListOption select(T? v) {
+    if (v == null) {
+      return this;
+    }
+    if (value.contains(v)) {
+      final List<T> newValue = List.from(value)..remove(v);
+      return ListOption<T>.dirty(value: newValue);
+    } else {
+      final List<T> newValue = List.from(value)..add(v);
+      return ListOption<T>.dirty(value: newValue);
+    }
+  }
+
+  @override
+  ValidationError? validator(List<T>? value) {
+    return value?.isNotEmpty == true ? null : ValidationError.invalid;
+  }
+}

packages/wyatt_form_bloc/lib/src/validators/validators.dart

@@ -18,6 +18,7 @@ export 'boolean.dart';
 export 'confirmed_password.dart';
 export 'email.dart';
 export 'iban.dart';
+export 'list_option.dart';
 export 'name.dart';
 export 'password.dart';
 export 'phone.dart';