first commit

lib/config/dependencies.dart

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+import "package:flutter/widgets.dart";
+import "package:nested/nested.dart";
+import "package:provider/provider.dart";
+import "package:seshat/data/services/websocket_client.dart";
+
+List<SingleChildWidget> get providers {
+  return [Provider(create: (context) => WebsocketClient())];
+}

lib/data/repositories/owner_repository.dart

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+import 'dart:convert';
+
+import 'package:seshat/data/services/api_client.dart';
+import 'package:seshat/data/services/websocket_client.dart';
+import 'package:seshat/domain/models/owner.dart';
+import 'package:seshat/utils/result.dart';
+
+class OwnerRepository {
+  OwnerRepository({
+    required ApiClient apiClient,
+    required WebsocketClient wsClient,
+  }) : _apiClient = apiClient,
+       _wsClient = wsClient;
+
+  final ApiClient _apiClient;
+  final WebsocketClient _wsClient;
+  List<Owner>? _cachedData;
+
+  Future<Result<List<Owner>>> getOwners() async {
+    if (_cachedData == null) {
+      final result = await _apiClient.getOwners();
+
+      if (result is Ok<List<Owner>>) {
+        _cachedData = result.value;
+      }
+
+      return result;
+    } else {
+      return Result.ok(_cachedData!);
+    }
+  }
+
+  Stream<Owner> liveOwners() async* {
+    await for (String data in _wsClient.connect()) {
+      Map<String, dynamic> decodedData = jsonDecode(
+        data,
+      ).cast<Map<String, dynamic>>();
+      Owner owner = Owner.fromJSON(decodedData);
+      if (_cachedData == null) {
+        getOwners();
+      } else {
+        _cachedData!.add(owner);
+        yield* Stream.value(owner);
+      }
+    }
+  }
+}

lib/data/services/api_client.dart

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+import 'package:seshat/domain/models/owner.dart';
+import 'package:seshat/utils/result.dart';
+
+class ApiClient {
+  Future<Result<List<Owner>>> getOwners() async {
+    return Result.ok(<Owner>[]);
+  }
+}

lib/data/services/websocket_client.dart

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+import 'package:web_socket_channel/web_socket_channel.dart';
+
+class WebsocketClient {
+  static const String _host = "ws://bal.ninjdai.fr:3000";
+
+  Stream<dynamic> connect() {
+    final channel = WebSocketChannel.connect(Uri.parse("$_host/ws"));
+    return channel.stream;
+  }
+}

lib/domain/models/owner.dart

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+import 'package:flutter/material.dart';
+
+class Owner extends ChangeNotifier {
+  Owner({
+    required this.firstName,
+    required this.lastName,
+    required this.contact,
+    required this.id,
+  });
+
+  String firstName;
+  String lastName;
+  String contact;
+  int id;
+
+  factory Owner.fromJSON(Map<String, dynamic> json) => Owner(
+    contact: json["contact"],
+    firstName: json["first_name"],
+    lastName: json["last_name"],
+    id: json["id"],
+  );
+}

lib/main.dart

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+import 'package:flutter/material.dart';
+import 'package:logging/logging.dart';
+import 'package:provider/provider.dart';
+import 'package:seshat/config/dependencies.dart';
+import 'package:seshat/routing/router.dart';
+
+// TODO: In router, make it so that the navbar is integrated in everyscreen that needs it -> consistancy (should be at least, hope so) so it stops jumping. Then, make it so that the pages are children of scaffold. That's all ?
+
+void main() {
+  Logger.root.level = Level.ALL;
+
+  // runApp(MultiProvider(providers: providers, child: const MyApp()));
+  runApp(const MyApp());
+}
+
+class MyApp extends StatelessWidget {
+  const MyApp({super.key});
+
+  // This widget is the root of your application.
+  @override
+  Widget build(BuildContext context) {
+    return MaterialApp.router(routerConfig: router());
+  }
+}
+
+// class Root extends StatefulWidget {
+//   const Root({super.key});
+
+//   @override
+//   State<Root> createState() => _RootState();
+// }
+
+// class _RootState extends State<Root> {
+//   var selectedIndex = 1;
+//   @override
+//   Widget build(BuildContext context) {
+//     final theme = Theme.of(context);
+//     return AnnotatedRegion(
+//       value: SystemUiOverlayStyle(
+//         statusBarBrightness: Brightness.light,
+//         statusBarIconBrightness: Brightness.light,
+//       ),
+//       child: Scaffold(
+//         appBar: null,
+//         bottomNavigationBar: NavigationBar(
+//           destinations: const <Widget>[
+//             NavigationDestination(icon: Icon(Icons.home), label: "Home"),
+//             NavigationDestination(
+//               icon: Icon(Icons.plus_one_outlined),
+//               label: "Ajout",
+//             ),
+//             NavigationDestination(icon: Icon(Icons.sell), label: "Vente"),
+//           ],
+//           selectedIndex: selectedIndex,
+//           onDestinationSelected: (int index) {
+//             setState(() {
+//               selectedIndex = index;
+//             });
+//           },
+//           indicatorColor: theme.highlightColor,
+//         ),
+//         body: switch (selectedIndex) {
+//           0 => Add(title: "Home Page"),
+//           1 => MultiProvider(
+//             providers: [
+//               ChangeNotifierProvider(
+//                 create: (context) => TabScreen("scanPage"),
+//               ),
+//               ChangeNotifierProvider(
+//                 create: (context) =>
+//                     Owner("UEAuvergne", "unionetudianteauvergne@gmail.com"),
+//               ),
+//             ],
+//             child: Add(title: "Ajout"),
+//           ),
+//           _ => Add(title: "Wildcard"),
+//         },
+//       ),
+//     );
+//   }
+// }

lib/routing/router.dart

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+import 'package:flutter/material.dart';
+import 'package:go_router/go_router.dart';
+import 'package:seshat/routing/routes.dart';
+import 'package:seshat/ui/add_page/view_model/add_view_model.dart';
+import 'package:seshat/ui/add_page/widgets/add_page.dart';
+import 'package:seshat/ui/core/ui/navigation_bar.dart';
+import 'package:seshat/ui/home_page/home_page.dart';
+import 'package:seshat/ui/sell_page/sell_page.dart';
+
+GoRouter router() => GoRouter(
+  initialLocation: Routes.add,
+  routes: [
+    GoRoute(
+      path: Routes.home,
+      pageBuilder: (context, state) => NoTransitionPage(child: HomePage()),
+      routes: [
+        GoRoute(
+          path: Routes.add,
+          pageBuilder: (context, state) =>
+              NoTransitionPage(child: AddPage(viewModel: AddViewModel())),
+          // routes: [
+          // GoRoute(path: Routes.addForm),
+          // GoRoute(path: Routes.addOwner),
+          // GoRoute(path: Routes.addPrice),
+          // ],
+        ),
+        GoRoute(
+          path: Routes.sell,
+          pageBuilder: (context, state) => NoTransitionPage(child: SellPage()),
+        ),
+      ],
+    ),
+  ],
+);

lib/routing/routes.dart

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+abstract final class Routes {
+  // ==[ HOME ]==
+  static const home = '/';
+
+  // ==[ ADD ]==
+  static const add = '/add';
+  static const addOwner = '/add/owner';
+  static const addPrice = '/add/price';
+  static const addForm = '/add/form';
+
+  // ==[ SELL ]==
+  static const sell = '/sell';
+}

lib/ui/add_page/view_model/add_view_model.dart

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+import 'package:flutter/foundation.dart';
+import 'package:flutter/material.dart';
+import 'package:logging/logging.dart';
+import 'package:seshat/domain/models/owner.dart';
+
+class AddViewModel extends ChangeNotifier {
+  AddViewModel();
+
+  final _log = Logger("AddViewModel");
+
+  Owner? _currentOwner;
+  Owner? get currentOwner => _currentOwner;
+  set currentOwner(Owner? owner) {
+    _currentOwner = owner;
+    notifyListeners();
+  }
+
+  List<Owner>? _owners = [
+    Owner(
+      firstName: "Jean",
+      lastName: "Henri",
+      contact: "contact@gmail.com",
+      id: 1,
+    ),
+    Owner(
+      firstName: "Jeanette",
+      lastName: "Henriette",
+      contact: "contact@gmail.com",
+      id: 2,
+    ),
+    Owner(
+      firstName: "Jacques",
+      lastName: "Gerard",
+      contact: "contact@gmail.com",
+      id: 3,
+    ),
+    Owner(
+      firstName: "Jacquelines",
+      lastName: "Geraldine",
+      contact: "contact@gmail.com",
+      id: 4,
+    ),
+    Owner(
+      firstName: "Louis",
+      lastName: "Valentin",
+      contact: "contact@gmail.com",
+      id: 5,
+    ),
+    Owner(
+      firstName: "Louise",
+      lastName: "Valentine",
+      contact: "contact@gmail.com",
+      id: 6,
+    ),
+  ];
+
+  List<Owner>? get owners => _owners;
+  Owner addOwner(String firstName, String lastName, String contact) {
+    _owners!.add(
+      Owner(
+        firstName: firstName,
+        lastName: lastName,
+        contact: contact,
+        id: _owners!.last.id + 1,
+      ),
+    );
+    notifyListeners();
+    return Owner(
+      firstName: firstName,
+      lastName: lastName,
+      contact: contact,
+      id: 0,
+    );
+  }
+}

lib/ui/add_page/widgets/add_page.dart

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+import 'package:flutter/material.dart';
+import 'package:flutter_svg/svg.dart';
+import 'package:mobile_scanner/mobile_scanner.dart';
+import 'package:seshat/ui/add_page/view_model/add_view_model.dart';
+import 'package:seshat/ui/add_page/widgets/owner_popup.dart';
+import 'package:seshat/ui/core/ui/navigation_bar.dart';
+
+class AddPage extends StatefulWidget {
+  const AddPage({super.key, required this.viewModel});
+
+  final AddViewModel viewModel;
+
+  @override
+  State<AddPage> createState() => _AddPageState();
+}
+
+class _AddPageState extends State<AddPage> {
+  bool askPrice = true;
+  @override
+  Widget build(BuildContext context) {
+    final MobileScannerController controller = MobileScannerController(
+      formats: [BarcodeFormat.ean13],
+      detectionTimeoutMs: 1000,
+    );
+    // return Consumer<TabScreen>(
+    // builder: (context, screen, child) {
+    return Scaffold(
+      bottomNavigationBar: AppNavigationBar(startIndex: 1),
+      body: Stack(
+        children: [
+          ColoredBox(color: Colors.black),
+          MobileScanner(
+            controller: controller,
+            onDetect: (barcodes) {
+              onBarcodeScan(barcodes, controller);
+            },
+          ),
+          SafeArea(
+            child: Column(
+              crossAxisAlignment: CrossAxisAlignment.center,
+              children: [
+                Center(
+                  child: Card(
+                    margin: EdgeInsets.symmetric(horizontal: 50),
+                    child: Column(
+                      children: [
+                        ListTile(
+                          leading: Icon(Icons.person),
+                          title: TextButton(
+                            child: Text("No"),
+                            onPressed: () => _ownerDialogBuilder(
+                              context,
+                              controller,
+                              widget.viewModel,
+                            ),
+                          ),
+                        ),
+                        ListTile(
+                          leading: Icon(Icons.attach_money),
+                          title: TextButton(
+                            child: Text(
+                              (askPrice)
+                                  ? "Demander à chaque fois"
+                                  : "Prix libre toujours",
+                            ),
+                            onPressed: () {
+                              setState(() {
+                                askPrice = !askPrice;
+                              });
+                            },
+                          ),
+                        ),
+                      ],
+                    ),
+                  ),
+                ),
+                Expanded(child: SizedBox()),
+                SvgPicture.asset('assets/scan-overlay.svg'),
+                Expanded(child: SizedBox()),
+                TextButton(
+                  onPressed: () {},
+                  child: Text("Enregistrer manuellement"),
+                ),
+              ],
+            ),
+          ),
+        ],
+      ),
+    );
+    // },
+    // );
+  }
+}
+
+void onBarcodeScan(
+  BarcodeCapture barcodes,
+  MobileScannerController controller,
+) {
+  return;
+}
+
+Future<void> _ownerDialogBuilder(
+  BuildContext context,
+  MobileScannerController controller,
+  AddViewModel viewModel,
+) {
+  controller.stop();
+
+  void onPressAccept(BuildContext localContext) {
+    controller.start();
+    Navigator.of(localContext).pop();
+  }
+
+  return showDialog(
+    context: context,
+    barrierDismissible: false,
+    builder: (context) =>
+        OwnerPopup(viewModel: viewModel, onPressAccept: onPressAccept),
+  );
+}

lib/ui/add_page/widgets/owner_popup.dart

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+import 'package:flutter/material.dart';
+import 'package:seshat/domain/models/owner.dart';
+import 'package:seshat/ui/add_page/view_model/add_view_model.dart';
+
+class OwnerPopup extends StatefulWidget {
+  const OwnerPopup({
+    super.key,
+    required this.viewModel,
+    required this.onPressAccept,
+  });
+
+  final AddViewModel viewModel;
+  final Function(BuildContext) onPressAccept;
+
+  @override
+  State<OwnerPopup> createState() => _OwnerPopupState();
+}
+
+class _OwnerPopupState extends State<OwnerPopup> {
+  final GlobalKey<FormState> _formKey = GlobalKey<FormState>();
+  bool showNewOwner = false;
+  String? firstName;
+  String? lastName;
+  String? contact;
+  @override
+  Widget build(BuildContext context) {
+    final theme = Theme.of(context);
+    return ListenableBuilder(
+      listenable: widget.viewModel,
+      builder: (context, child) => AlertDialog(
+        title: Center(child: Text("Propriétaire du livre")),
+        content: Column(
+          mainAxisAlignment: MainAxisAlignment.center,
+          mainAxisSize: MainAxisSize.min,
+          children: [
+            Center(
+              child: Text(
+                (widget.viewModel.currentOwner == null)
+                    ? "Choix actuel : aucun"
+                    : "Choix actuel : ${widget.viewModel.currentOwner!.firstName} ${widget.viewModel.currentOwner!.lastName}",
+              ),
+            ),
+            SizedBox(height: 5),
+            (showNewOwner)
+                ? SizedBox()
+                : DropdownMenu<Owner>(
+                    enableFilter: true,
+                    label: Text("Rechercher un·e propriétaire"),
+                    dropdownMenuEntries: [
+                      for (var owner in widget.viewModel.owners!)
+                        DropdownMenuEntry(
+                          value: owner,
+                          label: "${owner.firstName} ${owner.lastName}",
+                          style: ButtonStyle(
+                            backgroundColor:
+                                (widget.viewModel.currentOwner == owner)
+                                ? WidgetStatePropertyAll<Color>(
+                                    theme.highlightColor,
+                                  )
+                                : WidgetStatePropertyAll<Color>(
+                                    theme.canvasColor,
+                                  ),
+                          ),
+                        ),
+                    ],
+                    initialSelection: widget.viewModel.currentOwner,
+                    onSelected: (Owner? owner) {
+                      widget.viewModel.currentOwner = owner;
+                    },
+                  ),
+            SizedBox(height: 20),
+            TextButton(
+              onPressed: () {
+                setState(() {
+                  showNewOwner = !showNewOwner;
+                });
+              },
+              child: Text(
+                (showNewOwner) ? "Annuler" : "Ajouter un propriétaire",
+              ),
+            ),
+            (!showNewOwner)
+                ? SizedBox()
+                : Form(
+                    key: _formKey,
+                    child: Column(
+                      children: [
+                        TextFormField(
+                          decoration: InputDecoration(
+                            labelText: "Nom",
+                            border: OutlineInputBorder(),
+                          ),
+                          onSaved: (newValue) {
+                            setState(() {
+                              lastName = newValue;
+                            });
+                          },
+                          validator: (value) {
+                            if (value == null || value.isEmpty) {
+                              return "Indiquez un nom";
+                            }
+                            return null;
+                          },
+                        ),
+                        SizedBox(height: 10),
+                        TextFormField(
+                          decoration: InputDecoration(
+                            labelText: "Prénom",
+                            border: OutlineInputBorder(),
+                          ),
+                          onSaved: (newValue) {
+                            setState(() {
+                              firstName = newValue;
+                            });
+                          },
+                          validator: (value) {
+                            if (value == null || value.isEmpty) {
+                              return "Indiquez un prénom";
+                            }
+                            return null;
+                          },
+                        ),
+                        SizedBox(height: 10),
+                        TextFormField(
+                          decoration: InputDecoration(
+                            labelText: "Contact",
+                            border: OutlineInputBorder(),
+                          ),
+                          onSaved: (newValue) {
+                            setState(() {
+                              contact = newValue;
+                            });
+                          },
+                          validator: (value) {
+                            if (value == null || value.isEmpty) {
+                              return "Indiquez un moyen de contact";
+                            }
+                            return null;
+                          },
+                        ),
+                        SizedBox(height: 10),
+                        ElevatedButton(
+                          onPressed: () {
+                            if (_formKey.currentState!.validate()) {
+                              _formKey.currentState!.save();
+                              setState(() {
+                                widget.viewModel.currentOwner = widget.viewModel
+                                    .addOwner(firstName!, lastName!, contact!);
+                                showNewOwner = false;
+                              });
+                            }
+                          },
+                          child: Text("Créer"),
+                        ),
+                      ],
+                    ),
+                  ),
+          ],
+        ),
+
+        actions: [
+          TextButton(
+            onPressed: () {
+              widget.onPressAccept(context);
+            },
+            child: Text("Valider"),
+          ),
+        ],
+      ),
+    );
+  }
+}

lib/ui/add_page/widgets/scan_screen.dart

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+import 'package:flutter/material.dart';
+import 'package:flutter_svg/svg.dart';
+import 'package:mobile_scanner/mobile_scanner.dart';
+import 'package:provider/provider.dart';
+
+// class ScanPage extends StatefulWidget {
+//   const ScanPage({super.key});
+
+//   @override
+//   State<ScanPage> createState() => _ScanPage();
+// }
+
+// class _ScanPage extends State<ScanPage> {
+//   final MobileScannerController controller = MobileScannerController(
+//     detectionTimeoutMs: 1000,
+//   );
+//   @override
+//   Widget build(BuildContext context) {
+//     return Stack(
+//       children: <Widget>[
+//         MobileScanner(
+//           controller: controller,
+//           onDetect: (result) {
+//             print(result.barcodes.first.rawValue);
+//           },
+//         ),
+//         SafeArea(
+//           child: Column(
+//             crossAxisAlignment: CrossAxisAlignment.center,
+//             children: [
+//               Center(
+//                 child: Card(
+//                   margin: EdgeInsets.symmetric(horizontal: 50),
+//                   child: Column(
+//                     children: [
+//                       Consumer<TabScreen>(
+//                         builder: (context, screen, child) {
+//                           return ListTile(
+//                             leading: Icon(Icons.person),
+//                             title: TextButton(
+//                               child: Text("No"),
+//                               onPressed: () {
+//                                 screen.change("ownerPage");
+//                               },
+//                             ),
+//                           );
+//                         },
+//                       ),
+//                       ListTile(
+//                         leading: Icon(Icons.attach_money),
+//                         title: TextButton(
+//                           child: Text("Demander à chaque fois"),
+//                           onPressed: () {
+//                             return;
+//                           },
+//                         ),
+//                       ),
+//                     ],
+//                   ),
+//                 ),
+//               ),
+//               Expanded(child: SizedBox()),
+//               SvgPicture.asset('assets/scan-overlay.svg'),
+//               Expanded(child: SizedBox()),
+//               TextButton(
+//                 onPressed: () {},
+//                 child: Text("Enregistrer manuellement"),
+//               ),
+//             ],
+//           ),
+//         ),
+//       ],
+//     );
+//   }
+// }

lib/ui/core/ui/navigation_bar.dart

@@ -0,0 +1,48 @@
+import 'package:flutter/material.dart';
+import 'package:go_router/go_router.dart';
+import 'package:logging/logging.dart';
+
+class AppNavigationBar extends StatefulWidget {
+  const AppNavigationBar({super.key, required this.startIndex});
+
+  final int startIndex;
+
+  @override
+  State<AppNavigationBar> createState() => _AppNavigationBarState();
+}
+
+class _AppNavigationBarState extends State<AppNavigationBar> {
+  final Logger _log = Logger("chose");
+
+  @override
+  Widget build(BuildContext context) {
+    var selectedIndex = widget.startIndex;
+    _log.info("We at $selectedIndex");
+    return NavigationBar(
+      destinations: [
+        NavigationDestination(icon: Icon(Icons.home), label: "Home"),
+        NavigationDestination(icon: Icon(Icons.add), label: "Ajout"),
+        NavigationDestination(icon: Icon(Icons.remove), label: "Vente"),
+      ],
+      selectedIndex: selectedIndex,
+      onDestinationSelected: (index) {
+        setState(() {
+          selectedIndex = index;
+        });
+        switch (index) {
+          case 0:
+            context.go('/');
+            break;
+          case 1:
+            context.go('/add');
+            break;
+          case 2:
+            context.go('/sell');
+            break;
+          default:
+            context.go("/");
+        }
+      },
+    );
+  }
+}

lib/ui/home_page/home_page.dart

@@ -0,0 +1,16 @@
+import 'package:flutter/material.dart';
+import 'package:flutter/widgets.dart';
+import 'package:seshat/ui/core/ui/navigation_bar.dart';
+
+class HomePage extends StatelessWidget {
+  const HomePage({super.key});
+
+  @override
+  Widget build(BuildContext context) {
+    return Scaffold(
+      bottomNavigationBar: AppNavigationBar(startIndex: 0),
+      body: Center(child: Text("Home page.")),
+    );
+    // return Center(child: Text("Home page;"));
+  }
+}

lib/ui/sell_page/sell_page.dart

@@ -0,0 +1,16 @@
+import 'package:flutter/material.dart';
+import 'package:flutter/widgets.dart';
+import 'package:seshat/ui/core/ui/navigation_bar.dart';
+
+class SellPage extends StatelessWidget {
+  const SellPage({super.key});
+
+  @override
+  Widget build(BuildContext context) {
+    return Scaffold(
+      bottomNavigationBar: AppNavigationBar(startIndex: 2),
+      body: Center(child: Text("Sell page.")),
+    );
+    // return Center(child: Text("Sell page."));
+  }
+}

lib/utils/command.dart

@@ -0,0 +1,97 @@
+// Copyright 2024 The Flutter team. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'dart:async';
+
+import 'package:flutter/foundation.dart';
+
+import 'result.dart';
+
+typedef CommandAction0<T> = Future<Result<T>> Function();
+typedef CommandAction1<T, A> = Future<Result<T>> Function(A);
+
+/// Facilitates interaction with a ViewModel.
+///
+/// Encapsulates an action,
+/// exposes its running and error states,
+/// and ensures that it can't be launched again until it finishes.
+///
+/// Use [Command0] for actions without arguments.
+/// Use [Command1] for actions with one argument.
+///
+/// Actions must return a [Result].
+///
+/// Consume the action result by listening to changes,
+/// then call to [clearResult] when the state is consumed.
+abstract class Command<T> extends ChangeNotifier {
+  Command();
+
+  bool _running = false;
+
+  /// True when the action is running.
+  bool get running => _running;
+
+  Result<T>? _result;
+
+  /// true if action completed with error
+  bool get error => _result is Error;
+
+  /// true if action completed successfully
+  bool get completed => _result is Ok;
+
+  /// Get last action result
+  Result? get result => _result;
+
+  /// Clear last action result
+  void clearResult() {
+    _result = null;
+    notifyListeners();
+  }
+
+  /// Internal execute implementation
+  Future<void> _execute(CommandAction0<T> action) async {
+    // Ensure the action can't launch multiple times.
+    // e.g. avoid multiple taps on button
+    if (_running) return;
+
+    // Notify listeners.
+    // e.g. button shows loading state
+    _running = true;
+    _result = null;
+    notifyListeners();
+
+    try {
+      _result = await action();
+    } finally {
+      _running = false;
+      notifyListeners();
+    }
+  }
+}
+
+/// [Command] without arguments.
+/// Takes a [CommandAction0] as action.
+class Command0<T> extends Command<T> {
+  Command0(this._action);
+
+  final CommandAction0<T> _action;
+
+  /// Executes the action.
+  Future<void> execute() async {
+    await _execute(_action);
+  }
+}
+
+/// [Command] with one argument.
+/// Takes a [CommandAction1] as action.
+class Command1<T, A> extends Command<T> {
+  Command1(this._action);
+
+  final CommandAction1<T, A> _action;
+
+  /// Executes the action with the argument.
+  Future<void> execute(A argument) async {
+    await _execute(() => _action(argument));
+  }
+}

lib/utils/result.dart

@@ -0,0 +1,48 @@
+// Copyright 2024 The Flutter team. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+/// Utility class to wrap result data
+///
+/// Evaluate the result using a switch statement:
+/// ```dart
+/// switch (result) {
+///   case Ok(): {
+///     print(result.value);
+///   }
+///   case Error(): {
+///     print(result.error);
+///   }
+/// }
+/// ```
+sealed class Result<T> {
+  const Result();
+
+  /// Creates a successful [Result], completed with the specified [value].
+  const factory Result.ok(T value) = Ok._;
+
+  /// Creates an error [Result], completed with the specified [error].
+  const factory Result.error(Exception error) = Error._;
+}
+
+/// Subclass of Result for values
+final class Ok<T> extends Result<T> {
+  const Ok._(this.value);
+
+  /// Returned value in result
+  final T value;
+
+  @override
+  String toString() => 'Result<$T>.ok($value)';
+}
+
+/// Subclass of Result for errors
+final class Error<T> extends Result<T> {
+  const Error._(this.error);
+
+  /// Returned error in result
+  final Exception error;
+
+  @override
+  String toString() => 'Result<$T>.error($error)';
+}