fix: Improve receiving shares

lib/features/tasks/model/pending_tasks_notifier.dart

@@ -0,0 +1,68 @@
+import 'dart:async';
+
+import 'package:flutter/material.dart';
+import 'package:paperless_api/paperless_api.dart';
+
+class PendingTasksNotifier extends ValueNotifier<Map<String, Task>> {
+  final PaperlessTasksApi _api;
+
+  final Map<String, StreamSubscription> _subscriptions = {};
+
+  PendingTasksNotifier(this._api) : super({});
+
+  @override
+  void dispose() {
+    stopListeningToTaskChanges();
+    super.dispose();
+  }
+
+  void listenToTaskChanges(String taskId) {
+    final sub = _api.listenForTaskChanges(taskId).listen(
+      (task) {
+        if (value.containsKey(taskId)) {
+          final oldTask = value[taskId]!;
+          if (oldTask.status != task.status) {
+            // Only notify of changes if task status has changed...
+            value = {...value, taskId: task};
+            notifyListeners();
+          }
+        } else {
+          value = {...value, taskId: task};
+          notifyListeners();
+        }
+      },
+    );
+    sub
+      ..onDone(() {
+        sub.cancel();
+        value = value..remove(taskId);
+        notifyListeners();
+      })
+      ..onError((_) {
+        sub.cancel();
+        value = value..remove(taskId);
+        notifyListeners();
+      });
+
+    _subscriptions.putIfAbsent(taskId, () => sub);
+  }
+
+  void stopListeningToTaskChanges([String? taskId]) {
+    if (taskId != null) {
+      _subscriptions[taskId]?.cancel();
+      _subscriptions.remove(taskId);
+    } else {
+      _subscriptions.forEach((key, value) {
+        value.cancel();
+        _subscriptions.remove(key);
+      });
+    }
+  }
+
+  Future<void> acknowledgeTasks(Iterable<String> taskIds) async {
+    final tasks = value.values.where((task) => taskIds.contains(task.taskId));
+    await Future.wait([for (var task in tasks) _api.acknowledgeTask(task)]);
+    value = value..removeWhere((key, value) => taskIds.contains(key));
+    notifyListeners();
+  }
+}