make NotificationsController work off of rowIds

lib/controllers/notifications.dart

@@ -1,33 +1,61 @@
 import "package:fast_immutable_collections/fast_immutable_collections.dart";
 import "package:flutter_riverpod/flutter_riverpod.dart";
 import "package:nexus/controllers/client.dart";
+import "package:nexus/controllers/rooms.dart";
 import "package:nexus/models/event.dart";
 
 typedef NotificationsRequest = (UnreadType? unreadType, String? roomId);
 
 class NotificationsController([final NotificationsRequest? request])
-    extends AsyncNotifier<IList<Event>> {
+    extends AsyncNotifier<IList<(int, String)>> {
+  static const virtualRoomId = "!notifications";
+
   @override
-  Future<IList<Event>> build() async {
+  Future<IList<(int, String)>> build() async {
     final client = ref.read(ClientController.provider.notifier);
 
     final (unreadType, roomId) = request ?? (null, null);
 
-    return await client.getMentions(
+    final mentions = await client.getMentions(
       .new(
         maxTimestamp: .now(),
         unreadType: unreadType ?? .highlight,
         roomId: roomId,
       ),
     );
+
+    ref
+        .watch(RoomsController.provider.notifier)
+        .update(
+          .new({
+            virtualRoomId: .new(
+              events: IMap.fromIterable(
+                mentions,
+                keyMapper: (event) => event.rowId,
+              ),
+            ),
+          }),
+          .new(),
+        );
+
+    return .new(mentions.map((event) => (event.rowId, event.roomId)));
   }
 
   Future<void> loadOlder() async {
     final currentNotifications = await future;
     state = .loading();
     state = await .guard(() async {
-      final lastTs = currentNotifications.lastOrNull?.timestamp;
-      if (lastTs == null) return const .empty();
+      final lastNotification = currentNotifications.lastOrNull?.$1;
+      final lastTs = lastNotification == null
+          ? null
+          : ref.watch(
+              RoomsController.provider.select(
+                (rooms) =>
+                    rooms[virtualRoomId]?.events[lastNotification]?.timestamp,
+              ),
+            );
+
+      if (lastTs == null) return currentNotifications;
 
       final client = ref.read(ClientController.provider.notifier);
       final (unreadType, roomId) = request ?? (null, null);
@@ -40,14 +68,30 @@ class NotificationsController([final NotificationsRequest? request])
         ),
       );
 
-      return currentNotifications.addAll(newNotifications);
+      ref
+          .watch(RoomsController.provider.notifier)
+          .update(
+            .new({
+              virtualRoomId: .new(
+                events: IMap.fromIterable(
+                  newNotifications,
+                  keyMapper: (event) => event.rowId,
+                ),
+              ),
+            }),
+            .new(),
+          );
+
+      return currentNotifications.addAll(
+        newNotifications.map((event) => (event.rowId, event.roomId)),
+      );
     });
   }
 
   static final provider = AsyncNotifierProvider.family
       .autoDispose<
         NotificationsController,
-        IList<Event>,
+        IList<(int, String)>,
         NotificationsRequest?
       >(NotificationsController.new);
 }