Add Worker service with isolated task management and integrate into app

finlog_app/app/lib/main.dart

@@ -1,6 +1,7 @@
 import 'package:flutter/material.dart';
 import 'package:fluttery/fluttery.dart';
 import 'package:fluttery/logger.dart';
+import 'package:fluttery/worker.dart';
 
 Future<void> main() async {
   // Ensures that the Flutter engine and widget binding
@@ -22,24 +23,11 @@ class MyApp extends StatelessWidget {
   // This widget is the root of your application.
   @override
   Widget build(BuildContext context) {
+    App.service<Logger>().info("test");
+
     return MaterialApp(
       title: 'Flutter Demo',
       theme: ThemeData(
-        // This is the theme of your application.
-        //
-        // TRY THIS: Try running your application with "flutter run". You'll see
-        // the application has a purple toolbar. Then, without quitting the app,
-        // try changing the seedColor in the colorScheme below to Colors.green
-        // and then invoke "hot reload" (save your changes or press the "hot
-        // reload" button in a Flutter-supported IDE, or press "r" if you used
-        // the command line to start the app).
-        //
-        // Notice that the counter didn't reset back to zero; the application
-        // state is not lost during the reload. To reset the state, use hot
-        // restart instead.
-        //
-        // This works for code too, not just values: Most code changes can be
-        // tested with just a hot reload.
         colorScheme: ColorScheme.fromSeed(seedColor: Colors.deepPurple),
       ),
       home: const MyHomePage(title: 'Flutter Demo Home Page'),
@@ -50,15 +38,6 @@ class MyApp extends StatelessWidget {
 class MyHomePage extends StatefulWidget {
   const MyHomePage({super.key, required this.title});
 
-  // This widget is the home page of your application. It is stateful, meaning
-  // that it has a State object (defined below) that contains fields that affect
-  // how it looks.
-
-  // This class is the configuration for the state. It holds the values (in this
-  // case the title) provided by the parent (in this case the App widget) and
-  // used by the build method of the State. Fields in a Widget subclass are
-  // always marked "final".
-
   final String title;
 
   @override
@@ -69,51 +48,27 @@ class _MyHomePageState extends State<MyHomePage> {
   int _counter = 0;
 
   void _incrementCounter() {
+    App.service<Worker>().spawn("worker-$_counter", () async {
+      App.service<Logger>().info("test");
+
+      await Future.delayed(const Duration(seconds: 10));
+
+      App.service<Logger>().info("end worker");
+    });
     setState(() {
-      // This call to setState tells the Flutter framework that something has
-      // changed in this State, which causes it to rerun the build method below
-      // so that the display can reflect the updated values. If we changed
-      // _counter without calling setState(), then the build method would not be
-      // called again, and so nothing would appear to happen.
       _counter++;
     });
   }
 
   @override
   Widget build(BuildContext context) {
-    // This method is rerun every time setState is called, for instance as done
-    // by the _incrementCounter method above.
-    //
-    // The Flutter framework has been optimized to make rerunning build methods
-    // fast, so that you can just rebuild anything that needs updating rather
-    // than having to individually change instances of widgets.
     return Scaffold(
       appBar: AppBar(
-        // TRY THIS: Try changing the color here to a specific color (to
-        // Colors.amber, perhaps?) and trigger a hot reload to see the AppBar
-        // change color while the other colors stay the same.
         backgroundColor: Theme.of(context).colorScheme.inversePrimary,
-        // Here we take the value from the MyHomePage object that was created by
-        // the App.build method, and use it to set our appbar title.
         title: Text(widget.title),
       ),
       body: Center(
-        // Center is a layout widget. It takes a single child and positions it
-        // in the middle of the parent.
         child: Column(
-          // Column is also a layout widget. It takes a list of children and
-          // arranges them vertically. By default, it sizes itself to fit its
-          // children horizontally, and tries to be as tall as its parent.
-          //
-          // Column has various properties to control how it sizes itself and
-          // how it positions its children. Here we use mainAxisAlignment to
-          // center the children vertically; the main axis here is the vertical
-          // axis because Columns are vertical (the cross axis would be
-          // horizontal).
-          //
-          // TRY THIS: Invoke "debug painting" (choose the "Toggle Debug Paint"
-          // action in the IDE, or press "p" in the console), to see the
-          // wireframe for each widget.
           mainAxisAlignment: MainAxisAlignment.center,
           children: <Widget>[
             const Text('You have pushed the button this many times:'),
@@ -121,6 +76,14 @@ class _MyHomePageState extends State<MyHomePage> {
               '$_counter',
               style: Theme.of(context).textTheme.headlineMedium,
             ),
+            TextButton(
+              onPressed: () {
+                print(
+                  "active workers: ${App.service<Worker>().getActiveWorkers().length}",
+                );
+              },
+              child: Text("Print workers"),
+            ),
           ],
         ),
       ),

finlog_app/fluttery/lib/fluttery.dart

@@ -6,6 +6,8 @@ import 'package:fluttery/secure_storage.dart';
 import 'package:fluttery/src/logger/logger_impl.dart';
 import 'package:fluttery/src/preferences/preferences_impl.dart';
 import 'package:fluttery/src/storage/secure/secure_storage_impl.dart';
+import 'package:fluttery/src/system/worker/worker_impl.dart';
+import 'package:fluttery/worker.dart';
 import 'package:kiwi/kiwi.dart';
 import 'package:shared_preferences/shared_preferences.dart';
 
@@ -31,12 +33,12 @@ class App {
 
   /// Registers the default services required by the application.
   static Future<void> registerDefaultServices() async {
-    registerService<Logger>(() => LoggerImpl());
-
     final prefs = await SharedPreferences.getInstance();
-    registerService<Preferences>(() => PreferencesImpl(instance: prefs));
 
+    registerService<Logger>(() => LoggerImpl());
+    registerService<Preferences>(() => PreferencesImpl(instance: prefs));
     registerService<SecureStorage>(() => SecureStorageImpl());
+    registerService<Worker>(() => WorkerImpl());
   }
 }
 

finlog_app/fluttery/lib/src/system/worker/worker_impl.dart

@@ -0,0 +1,142 @@
+import 'dart:async';
+import 'dart:isolate';
+
+import 'package:flutter/services.dart'
+    show ServicesBinding, RootIsolateToken, BackgroundIsolateBinaryMessenger;
+
+import 'package:fluttery/fluttery.dart';
+import 'package:fluttery/logger.dart';
+import 'package:fluttery/worker.dart';
+
+class WorkerImpl implements Worker {
+  WorkerImpl({
+    this.defaultTimeout,
+    this.maxHistory = 100,
+    RootIsolateToken? rootToken, // optional for tests
+  }) : _rootToken =
+           rootToken ?? ServicesBinding.rootIsolateToken; // <— static getter
+
+  final Duration? defaultTimeout;
+  final int maxHistory;
+
+  // Captured from the root isolate (may be null in some test envs)
+  final RootIsolateToken? _rootToken;
+
+  int _seq = 0;
+  final Map<String, WorkerInfo> _active = {};
+  final List<WorkerInfo> _history = [];
+
+  @override
+  Future<T> spawn<T>(
+    String debugName,
+    FutureOr<T> Function() task, {
+    void Function()? preTask,
+    Duration? timeout,
+  }) {
+    final id = (++_seq).toString().padLeft(6, '0');
+    final started = DateTime.now();
+
+    _active[id] = WorkerInfo(
+      id: id,
+      name: debugName,
+      startedAt: started,
+      status: WorkerStatus.running,
+    );
+
+    Future<T> inner() async {
+      final token = _rootToken; // captured into closure
+
+      return Isolate.run<T>(() async {
+        // Initialize platform channels for this background isolate.
+        if (token != null) {
+          BackgroundIsolateBinaryMessenger.ensureInitialized(token);
+        }
+
+        // Now it's safe to touch plugins (e.g., SharedPreferences).
+        await App.registerDefaultServices();
+
+        preTask?.call();
+
+        return await Future.sync(task);
+      }, debugName: debugName);
+    }
+
+    final effectiveTimeout = timeout ?? defaultTimeout;
+    final fut = effectiveTimeout == null
+        ? inner()
+        : inner().timeout(effectiveTimeout);
+
+    fut
+        .then((_) {
+          _finish(id, status: WorkerStatus.completed);
+        })
+        .catchError((e, st) {
+          _finish(
+            id,
+            status: e is TimeoutException
+                ? WorkerStatus.timedOut
+                : WorkerStatus.failed,
+            error: e,
+            stack: st,
+          );
+          // Best-effort logging
+          try {
+            App.service<Logger>().error(
+              'Worker job "$debugName" ($id) failed: $e',
+              st,
+            );
+          } catch (_) {}
+        });
+
+    return fut;
+  }
+
+  void _finish(
+    String id, {
+    required WorkerStatus status,
+    Object? error,
+    StackTrace? stack,
+  }) {
+    final prev = _active.remove(id);
+    final endedAt = DateTime.now();
+
+    final info = WorkerInfo(
+      id: prev?.id ?? id,
+      name: prev?.name ?? 'unknown',
+      startedAt: prev?.startedAt ?? endedAt,
+      status: status,
+      endedAt: endedAt,
+      error: error,
+      stackTrace: stack,
+    );
+
+    _history.insert(0, info);
+    if (_history.length > maxHistory) {
+      _history.removeRange(maxHistory, _history.length);
+    }
+  }
+
+  @override
+  List<WorkerInfo> getActiveWorkers() =>
+      _active.values.toList()
+        ..sort((a, b) => a.startedAt.compareTo(b.startedAt));
+
+  @override
+  List<WorkerInfo> getAllWorkers() => [...getActiveWorkers(), ..._history];
+
+  @override
+  WorkerInfo? getWorker(String id) {
+    final active = _active[id];
+    if (active != null) return active;
+    for (final w in _history) {
+      if (w.id == id) return w;
+    }
+    return null;
+  }
+
+  @override
+  void purge({Duration maxAge = const Duration(minutes: 30)}) {
+    final cutoff = DateTime.now().subtract(maxAge);
+    _history.removeWhere((w) => (w.endedAt ?? w.startedAt).isBefore(cutoff));
+  }
+}

finlog_app/fluttery/lib/worker.dart

@@ -0,0 +1,47 @@
+import 'dart:async';
+import 'package:fluttery/fluttery.dart';
+
+abstract class Worker extends Service {
+  Future<T> spawn<T>(
+    String debugName,
+    FutureOr<T> Function() task, {
+    void Function()? preTask,
+    Duration? timeout, // per-job override
+  });
+
+  /// Currently running jobs.
+  List<WorkerInfo> getActiveWorkers();
+
+  /// All known jobs (active + completed + failed), up to a capped history.
+  List<WorkerInfo> getAllWorkers();
+
+  /// Optional: get a single worker by id.
+  WorkerInfo? getWorker(String id);
+
+  /// Remove completed/failed jobs older than [maxAge] from history.
+  void purge({Duration maxAge = const Duration(minutes: 30)});
+}
+
+enum WorkerStatus { running, completed, failed, timedOut }
+
+class WorkerInfo {
+  WorkerInfo({
+    required this.id,
+    required this.name,
+    required this.startedAt,
+    required this.status,
+    this.endedAt,
+    this.error,
+    this.stackTrace,
+  });
+
+  final String id;
+  final String name;
+  final DateTime startedAt;
+  final WorkerStatus status;
+  final DateTime? endedAt;
+  final Object? error;
+  final StackTrace? stackTrace;
+
+  Duration get duration => ((endedAt ?? DateTime.now()).difference(startedAt));
+}

finlog_app/fluttery/test/system/worker/worker_impl_test.dart

@@ -0,0 +1,158 @@
+// test/system/worker/worker_impl_test.dart
+import 'dart:async';
+import 'dart:isolate';
+
+import 'package:flutter/services.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:fluttery/fluttery.dart';
+import 'package:fluttery/preferences.dart';
+import 'package:shared_preferences/shared_preferences.dart';
+
+import 'package:fluttery/src/system/worker/worker_impl.dart';
+import 'package:fluttery/worker.dart';
+
+Future<void> pumpMicro([int times = 10]) => pumpEventQueue(times: times);
+
+Future<void> waitFor(
+  bool Function() predicate, {
+  Duration timeout = const Duration(seconds: 2),
+  Duration step = const Duration(milliseconds: 20),
+}) async {
+  final deadline = DateTime.now().add(timeout);
+  while (DateTime.now().isBefore(deadline)) {
+    if (predicate()) return;
+    await Future<void>.delayed(step);
+  }
+  fail('Condition not met within $timeout');
+}
+
+void main() {
+  setUpAll(() async {
+    TestWidgetsFlutterBinding.ensureInitialized();
+    SharedPreferences.setMockInitialValues({});
+    expect(ServicesBinding.rootIsolateToken, isNotNull);
+  });
+
+  group('worker', () {
+    test(
+      'spawn returns value; preTask runs; active->history tracking',
+      () async {
+        final worker = WorkerImpl();
+        App.service<Preferences>().setBool("test", false);
+
+        var preCalled = false;
+
+        final fut = worker.spawn<int>(
+          'ok',
+          () async {
+            await Future.delayed(const Duration(milliseconds: 20));
+            return 7;
+          },
+          // Ensure the worker isolate has the prefs mock (even if not used).
+          preTask: () {
+            SharedPreferences.setMockInitialValues({});
+            preCalled = true;
+          },
+        );
+
+        // Shortly after spawn there should be one active job.
+        await Future<void>.delayed(const Duration(milliseconds: 10));
+        expect(worker.getActiveWorkers().length, 1);
+
+        final res = await fut;
+        expect(res, 7);
+        expect(preCalled, isTrue);
+
+        await waitFor(() => worker.getActiveWorkers().isEmpty);
+        await waitFor(() => worker.getAllWorkers().isNotEmpty);
+        final all = worker.getAllWorkers();
+        expect(all.first.status, WorkerStatus.completed);
+        expect(all.first.name, 'ok');
+      },
+      // If you still see VM callback warnings here, consider making
+      // Preferences lazy in your app code to avoid plugin calls on registration.
+      // skip: true,
+    );
+
+    test('timeout marks job as timedOut and throws TimeoutException', () async {
+      final worker = WorkerImpl(
+        defaultTimeout: const Duration(milliseconds: 50),
+      );
+
+      await expectLater(
+        worker.spawn<void>(
+          'timeout',
+          // Long task so the wrapper .timeout triggers
+          () async => Future.delayed(const Duration(milliseconds: 220)),
+          // Make sure prefs mock is available in the worker isolate even if
+          // App.registerDefaultServices touches SharedPreferences.
+          preTask: () =>
+              SharedPreferences.setMockInitialValues({}),
+        ),
+        throwsA(isA<TimeoutException>()),
+      );
+
+      // Wait until the worker updates history in its catchError path
+      await waitFor(() => worker.getAllWorkers().isNotEmpty);
+      final all = worker.getAllWorkers();
+      expect(all.first.status, WorkerStatus.timedOut);
+      expect(all.first.name, 'timeout');
+    });
+
+    test('failure marks job as failed and surfaces RemoteError', () async {
+      final worker = WorkerImpl();
+
+      await expectLater(
+        worker.spawn<void>(
+          'fail',
+          () async {
+            await Future<void>.delayed(const Duration(milliseconds: 10));
+            throw StateError('boom');
+          },
+          // Ensure plugin mocks exist if defaults touch plugins
+          preTask: () =>
+              SharedPreferences.setMockInitialValues({}),
+        ),
+        // Isolate.run returns a RemoteError to the caller isolate
+        throwsA(isA<RemoteError>()),
+      );
+
+      await waitFor(() => worker.getAllWorkers().isNotEmpty);
+      final all = worker.getAllWorkers();
+      expect(all.first.status, WorkerStatus.failed);
+      expect(all.first.name, 'fail');
+    });
+
+    test(
+      'getWorker while running, then after completion; purge removes old',
+      () async {
+        final worker = WorkerImpl();
+
+        final fut = worker.spawn<void>(
+          'long',
+          () async => Future.delayed(const Duration(milliseconds: 160)),
+          preTask: () =>
+              SharedPreferences.setMockInitialValues({}),
+        );
+
+        await Future<void>.delayed(const Duration(milliseconds: 25));
+        final active = worker.getActiveWorkers();
+        expect(active.length, 1);
+        final id = active.first.id;
+        expect(worker.getWorker(id)?.status, WorkerStatus.running);
+
+        await fut;
+        await waitFor(
+          () => worker.getWorker(id)?.status == WorkerStatus.completed,
+        );
+
+        expect(worker.getAllWorkers().length, 1);
+
+        worker.purge(maxAge: Duration.zero);
+        await pumpMicro();
+        expect(worker.getAllWorkers(), isEmpty);
+      },
+      // skip: true,
+    );
+  });
+}