💄 Optimize the notification overlays

lib/pods/notification.dart

@@ -1,3 +1,5 @@
+import 'dart:async';
+
 import 'package:island/models/account.dart';
 import 'package:riverpod_annotation/riverpod_annotation.dart';
 import 'package:uuid/uuid.dart';
@@ -13,6 +15,7 @@ class NotificationItem {
   final DateTime createdAt;
   final int index;
   final Duration duration;
+  final bool dismissed;
 
   NotificationItem({
     String? id,
@@ -20,11 +23,30 @@ class NotificationItem {
     DateTime? createdAt,
     required this.index,
     Duration? duration,
+    this.dismissed = false,
   }) : id = id ?? const Uuid().v4(),
        createdAt = createdAt ?? DateTime.now(),
        duration =
            duration ?? kNotificationBaseDuration + Duration(seconds: index);
 
+  NotificationItem copyWith({
+    String? id,
+    SnNotification? notification,
+    DateTime? createdAt,
+    int? index,
+    Duration? duration,
+    bool? dismissed,
+  }) {
+    return NotificationItem(
+      id: id ?? this.id,
+      notification: notification ?? this.notification,
+      createdAt: createdAt ?? this.createdAt,
+      index: index ?? this.index,
+      duration: duration ?? this.duration,
+      dismissed: dismissed ?? this.dismissed,
+    );
+  }
+
   @override
   bool operator ==(Object other) {
     if (identical(this, other)) return true;
@@ -37,6 +59,8 @@ class NotificationItem {
 
 @riverpod
 class NotificationState extends _$NotificationState {
+  final Map<String, Timer> _timers = {};
+
   @override
   List<NotificationItem> build() {
     return [];
@@ -49,6 +73,16 @@ class NotificationState extends _$NotificationState {
       duration: duration,
     );
     state = [...state, newItem];
+    _timers[newItem.id] = Timer(newItem.duration, () => dismiss(newItem.id));
+  }
+
+  void dismiss(String id) {
+    _timers[id]?.cancel();
+    _timers.remove(id);
+    final index = state.indexWhere((item) => item.id == id);
+    if (index != -1) {
+      state = List.from(state)..[index] = state[index].copyWith(dismissed: true);
+    }
   }
 
   void remove(String id) {
@@ -56,6 +90,10 @@ class NotificationState extends _$NotificationState {
   }
 
   void clear() {
+    for (final timer in _timers.values) {
+      timer.cancel();
+    }
+    _timers.clear();
     state = [];
   }
-}
+}