allow paginating in the historical timeline

lib/controllers/client.dart

@@ -17,6 +17,7 @@ import "package:nexus/models/gomuks_config.dart";
 import "package:nexus/models/oauth_auth_code_response.dart";
 import "package:nexus/models/open_graph_data.dart";
 import "package:nexus/models/paginate.dart";
+import "package:nexus/models/paginate_manual.dart";
 import "package:nexus/models/requests/deregister_pusher.dart";
 import "package:nexus/models/requests/download_media.dart";
 import "package:nexus/models/requests/get_event.dart";
@@ -30,6 +31,7 @@ import "package:nexus/models/requests/oauth/exchange_token.dart";
 import "package:nexus/models/requests/oauth/get_auth_url.dart";
 import "package:nexus/models/requests/oauth/register_client.dart";
 import "package:nexus/models/requests/paginate.dart";
+import "package:nexus/models/requests/paginate_manual.dart";
 import "package:nexus/models/requests/redact_event.dart";
 import "package:nexus/models/requests/register_pusher.dart";
 import "package:nexus/models/requests/report.dart";
@@ -229,6 +231,9 @@ class ClientController extends AsyncNotifier<int> {
   Future<Paginate> paginate(PaginateRequest request) async =>
       .fromJson(await _sendCommand("paginate", request.toJson()));
 
+  Future<PaginateManual> paginateManual(PaginateManualRequest request) async =>
+      .fromJson(await _sendCommand("paginate_manual", request.toJson()));
+
   Future<EventContext> getEventContext(GetEventContextRequest request) async =>
       .fromJson(await _sendCommand("get_event_context", request.toJson()));
 

lib/controllers/notifications.dart

@@ -7,8 +7,6 @@ typedef NotificationsRequest = (UnreadType? unreadType, String? roomId);
 
 class NotificationsController([final NotificationsRequest? request])
     extends AsyncNotifier<IList<Event>> {
-  static const limit = 20;
-
   @override
   Future<IList<Event>> build() async {
     final client = ref.read(ClientController.provider.notifier);
@@ -19,7 +17,6 @@ class NotificationsController([final NotificationsRequest? request])
       .new(
         maxTimestamp: .now(),
         unreadType: unreadType ?? .highlight,
-        limit: limit,
         roomId: roomId,
       ),
     );
@@ -39,7 +36,6 @@ class NotificationsController([final NotificationsRequest? request])
         .new(
           maxTimestamp: lastTs,
           unreadType: unreadType ?? .highlight,
-          limit: limit,
           roomId: roomId,
         ),
       );

lib/controllers/room_chat.dart

@@ -10,6 +10,7 @@ import "package:nexus/controllers/client.dart";
 import "package:nexus/controllers/rooms.dart";
 import "package:nexus/models/content/content.dart";
 import "package:nexus/models/content/reaction.dart";
+import "package:nexus/models/direction.dart";
 import "package:nexus/models/event.dart";
 import "package:nexus/models/requests/redact_event.dart";
 import "package:nexus/models/relation_type.dart";
@@ -60,14 +61,19 @@ class RoomChatController(final (String roomId, String? contextualEvent) info)
     if (info.$2 == null || timeline.map((e) => e.eventId).contains(info.$2)) {
       ref.watch(RoomsController.provider.select((rooms) => rooms[roomId]));
 
-      return .new(timeline: timeline, hasMore: room.hasMore);
+      return .new(
+        timeline: timeline,
+        hasMoreBackward: room.hasMore,
+        hasMoreForward: false,
+      );
     } else {
       final context = await client.getEventContext(
-        .new(roomId: roomId, eventId: info.$2!, limit: 20),
+        .new(roomId: roomId, eventId: info.$2!),
       );
       return .new(
         timeline: context.before.add(context.event).addAll(context.after),
-        hasMore: true,
+        hasMoreBackward: true,
+        hasMoreForward: true,
         historicalData: .new(start: context.start, end: context.end),
       );
     }
@@ -83,18 +89,19 @@ class RoomChatController(final (String roomId, String? contextualEvent) info)
         ),
       );
 
-  Future<void> loadOlder() async {
-    if (state.isLoading || state.value?.hasMore == false) return;
-
+  Future<void> paginate(Direction direction) async {
+    if (state.isLoading || state.value?.hasMoreBackward == false) return;
+    final chat = await future;
     state = .loading();
 
+    final client = ref.read(ClientController.provider.notifier);
+
+    if (chat?.historicalData == null) {
       final timelineKeys = ref
           .read(RoomsController.provider.select((value) => value[info.$1]))
           ?.timeline
           .keys;
-    final response = await ref
-        .read(ClientController.provider.notifier)
-        .paginate(
+      final response = await client.paginate(
         .new(
           roomId: info.$1,
           maxTimelineId: timelineKeys?.isNotEmpty == true
@@ -127,6 +134,43 @@ class RoomChatController(final (String roomId, String? contextualEvent) info)
             }),
             .new(),
           );
+    } else {
+      final paginationResponse = await client.paginateManual(
+        .new(
+          roomId: info.$1,
+          direction: direction,
+          since: direction == .forward
+              ? chat!.historicalData!.end
+              : chat!.historicalData!.start,
+        ),
+      );
+
+      state = .data(
+        .new(
+          timeline: direction == .forward
+              ? chat.timeline.addAll(paginationResponse.events)
+              : paginationResponse.events.addAll(chat.timeline),
+          hasMoreForward:
+              direction == .forward && paginationResponse.nextBatch == null
+              ? false
+              : chat.hasMoreForward,
+          hasMoreBackward:
+              direction == .backward && paginationResponse.nextBatch == null
+              ? false
+              : chat.hasMoreBackward,
+          historicalData: chat.historicalData?.copyWith(
+            start:
+                (direction == .backward
+                    ? paginationResponse.nextBatch
+                    : null) ??
+                chat.historicalData!.start,
+            end:
+                (direction == .forward ? paginationResponse.nextBatch : null) ??
+                chat.historicalData!.end,
+          ),
+        ),
+      );
+    }
   }
 
   Future<void> send(

lib/helpers/hooks/chat_scroll.dart

@@ -4,6 +4,7 @@ import "package:fast_immutable_collections/fast_immutable_collections.dart";
 import "package:flutter_hooks/flutter_hooks.dart";
 import "package:hooks_riverpod/hooks_riverpod.dart";
 import "package:material_ui/material_ui.dart";
+import "package:nexus/models/direction.dart";
 import "package:nexus/models/event.dart";
 import "package:nexus/models/room_chat.dart";
 import "package:super_sliver_list/super_sliver_list.dart";
@@ -20,7 +21,7 @@ final class ChatScroll({
 }) {
   factory use({
     required AsyncValue<RoomChat?> controllerData,
-    required Future<void> Function() loadOlder,
+    required Future<void> Function(Direction direction) paginate,
     required Future<void> Function() markRead,
     required String? contextualEvent,
     required void Function(String id) setContextualEvent,
@@ -118,20 +119,21 @@ final class ChatScroll({
       );
     }, [controllerData, anchorId.value]);
 
-    useEffect(
-      () {
-        const topThreshold = 500.0;
-        const bottomThreshold = 50.0;
+    useEffect(() {
+      const loadThreshold = 500.0;
+      const readThreshold = 50.0;
 
       Future<void> checkPosition() async {
         if (!scrollController.hasClients) return;
-          if (contextualEvent != null) return;
 
         final position = scrollController.position;
 
-          if (position.extentAfter <= topThreshold) {
-            await loadOlder();
-          } else if (position.extentBefore <= bottomThreshold) {
+        if (position.extentAfter <= loadThreshold) {
+          await paginate(Direction.backward);
+        } else if (contextualEvent != null &&
+            position.extentBefore <= loadThreshold) {
+          await paginate(Direction.forward);
+        } else if (position.extentBefore <= readThreshold) {
           await markRead();
         }
       }
@@ -141,9 +143,7 @@ final class ChatScroll({
       WidgetsBinding.instance.addPostFrameCallback((_) => checkPosition());
 
       return () => scrollController.removeListener(checkPosition);
-      },
-      [scrollController, controllerData, loadOlder, markRead, contextualEvent],
-    );
+    }, [scrollController, controllerData, paginate, markRead, contextualEvent]);
 
     double? resolveOffset(String itemId) {
       final historyIndex = split.history.indexWhere(

lib/models/direction.dart

@@ -0,0 +1,8 @@
+import "package:freezed_annotation/freezed_annotation.dart";
+
+enum Direction {
+  @JsonValue("f")
+  forward,
+  @JsonValue("b")
+  backward,
+}

lib/models/paginate_manual.dart

@@ -0,0 +1,19 @@
+import "package:fast_immutable_collections/fast_immutable_collections.dart";
+import "package:freezed_annotation/freezed_annotation.dart";
+import "package:nexus/models/event.dart";
+
+part "paginate_manual.freezed.dart";
+part "paginate_manual.g.dart";
+
+@Freezed(toJson: false, fromJson: false)
+@JsonSerializable()
+class const PaginateManual({
+  required final IList<Event> events,
+  final IList<Event> relatedEvents = const IList.empty(),
+  required final String? nextBatch,
+}) with _$PaginateManual {
+  Map<String, Object?> toJson() => _$PaginateManualToJson(this);
+
+  factory PaginateManual.fromJson(Map<String, Object?> json) =>
+      _$PaginateManualFromJson(json);
+}

lib/models/requests/get_event_context.dart

@@ -8,7 +8,7 @@ part "get_event_context.g.dart";
 class const GetEventContextRequest({
   required final String roomId,
   required final String eventId,
-  required final int limit,
+  final int limit = 20,
 }) with _$GetEventContextRequest {
   Map<String, Object?> toJson() => _$GetEventContextRequestToJson(this);
 

lib/models/requests/get_mentions.dart

@@ -9,7 +9,7 @@ part "get_mentions.g.dart";
 class GetMentionsRequest({
   @EpochDateTimeConverter() required final DateTime maxTimestamp,
   @JsonKey(name: "type") required final UnreadType unreadType,
-  required final int limit,
+  final int limit = 20,
   final String? roomId,
 }) with _$GetMentionsRequest {
   Map<String, Object?> toJson() => _$GetMentionsRequestToJson(this);

lib/models/requests/paginate_manual.dart

@@ -0,0 +1,22 @@
+import "package:freezed_annotation/freezed_annotation.dart";
+import "package:nexus/models/direction.dart";
+
+part "paginate_manual.freezed.dart";
+part "paginate_manual.g.dart";
+
+@Freezed(toJson: false, fromJson: false)
+@JsonSerializable()
+class const PaginateManualRequest({
+  required final String roomId,
+  // Root event ID of a thread to paginate
+  final String? threadRoot,
+  // Can be null for starting pagination of a thread
+  final String? since,
+  required final Direction direction,
+  final int limit = 20,
+}) with _$PaginateManualRequest {
+  Map<String, Object?> toJson() => _$PaginateManualRequestToJson(this);
+
+  factory PaginateManualRequest.fromJson(Map<String, Object?> json) =>
+      _$PaginateManualRequestFromJson(json);
+}

lib/models/room_chat.dart

@@ -9,7 +9,8 @@ part "room_chat.g.dart";
 @JsonSerializable()
 class const RoomChat({
   required final IList<Event> timeline,
-  required final bool hasMore,
+  required final bool hasMoreForward,
+  required final bool hasMoreBackward,
   final HistoricalData? historicalData,
 }) with _$RoomChat {
   Map<String, Object?> toJson() => _$RoomChatToJson(this);

lib/widgets/room_chat/room_chat.dart

@@ -73,7 +73,7 @@ final class const RoomChat({
 
     final scroll = ChatScroll.use(
       controllerData: controllerData,
-      loadOlder: notifier.loadOlder,
+      paginate: notifier.paginate,
       contextualEvent: contextualEvent.value,
       setContextualEvent: (id) => contextualEvent.value = id,
       markRead: () async {