feat: Do not load all timeline events from store at once

lib/src/database/database_api.dart

@@ -78,7 +78,12 @@ abstract class DatabaseApi {
 
   Future<List<User>> getUsers(int clientId, Room room);
 
-  Future<List<Event>> getEventList(int clientId, Room room);
+  Future<List<Event>> getEventList(
+    int clientId,
+    Room room, {
+    int start = 0,
+    int limit,
+  });
 
   Future<Uint8List?> getFile(Uri mxcUri);
 

lib/src/database/hive_database.dart

@@ -308,16 +308,9 @@ class FamedlySdkHiveDatabase extends DatabaseApi {
     return Event.fromJson(convertToJson(raw), room);
   }
 
-  @override
-  Future<List<Event>> getEventList(int clientId, Room room) async {
-    final List timelineEventIds =
-        (await _timelineFragmentsBox.get(MultiKey(room.id, '').toString()) ??
-            []);
-    final List sendingEventIds = (await _timelineFragmentsBox
-            .get(MultiKey(room.id, 'SENDING').toString()) ??
-        []);
-    final eventIds = sendingEventIds + timelineEventIds;
-    final events = await Future.wait(eventIds
+  /// Loads a whole list of events at once from the store for a specific room
+  Future<List<Event>> _getEventsByIds(List<String> eventIds, Room room) =>
+      Future.wait(eventIds
           .map(
             (eventId) async => Event.fromJson(
               convertToJson(
@@ -327,7 +320,36 @@ class FamedlySdkHiveDatabase extends DatabaseApi {
             ),
           )
           .toList());
-    return events;
+
+  @override
+  Future<List<Event>> getEventList(
+    int clientId,
+    Room room, {
+    int start = 0,
+    int? limit,
+  }) async {
+    // Get the synced event IDs from the store
+    final timelineKey = MultiKey(room.id, '').toString();
+    final timelineEventIds =
+        (await _timelineFragmentsBox.get(timelineKey) as List? ?? []);
+
+    // Get the local stored SENDING events from the store
+    late final List sendingEventIds;
+    if (start != 0) {
+      sendingEventIds = [];
+    } else {
+      final sendingTimelineKey = MultiKey(room.id, 'SENDING').toString();
+      sendingEventIds =
+          (await _timelineFragmentsBox.get(sendingTimelineKey) as List? ?? []);
+    }
+
+    // Combine those two lists while respecting the start and limit parameters.
+    final end = min(
+        timelineEventIds.length, start + (limit ?? timelineEventIds.length));
+    final eventIds =
+        sendingEventIds + timelineEventIds.getRange(start, end).toList();
+
+    return await _getEventsByIds(eventIds.cast<String>(), room);
   }
 
   @override

lib/src/room.dart

@@ -387,7 +387,7 @@ class Room {
 
   /// The default count of how much events should be requested when requesting the
   /// history of this room.
-  static const int defaultHistoryCount = 100;
+  static const int defaultHistoryCount = 30;
 
   /// Calculates the displayname. First checks if there is a name, then checks for a canonical alias and
   /// then generates a name from the heroes.
@@ -931,7 +931,8 @@ class Room {
   /// be received maximum. When the request is answered, [onHistoryReceived] will be triggered **before**
   /// the historical events will be published in the onEvent stream.
   Future<void> requestHistory(
-      {int historyCount = defaultHistoryCount, onHistoryReceived}) async {
+      {int historyCount = defaultHistoryCount,
+      void Function() onHistoryReceived}) async {
     if (prev_batch == null) {
       throw 'Tried to request history without a prev_batch token';
     }
@@ -1069,7 +1070,11 @@ class Room {
     await postLoad();
     var events;
     if (client.database != null) {
-      events = await client.database.getEventList(client.id, this);
+      events = await client.database.getEventList(
+        client.id,
+        this,
+        limit: defaultHistoryCount,
+      );
     } else {
       events = <Event>[];
     }

lib/src/timeline.dart

@@ -64,7 +64,6 @@ class Timeline {
   // This ensures that the entire history fetching only triggers `onUpdate` only *once*,
   // even if /sync's complete while history is being proccessed.
   bool _collectHistoryUpdates = false;
-  final Set<EventUpdate> _historyUpdates = <EventUpdate>{};
 
   bool get canRequestHistory {
     if (events.isEmpty) return true;
@@ -73,33 +72,37 @@ class Timeline {
 
   Future<void> requestHistory(
       {int historyCount = Room.defaultHistoryCount}) async {
-    if (!isRequestingHistory) {
+    if (isRequestingHistory) {
+      return;
+    }
     isRequestingHistory = true;
+    onUpdate?.call();
+
+    try {
+      // Look up for events in hive first
+      final eventsFromStore = await room.client.database?.getEventList(
+        room.client.id,
+        room,
+        start: events.length,
+        limit: Room.defaultHistoryCount,
+      );
+      if (eventsFromStore.isNotEmpty) {
+        events.addAll(eventsFromStore);
+      } else {
+        Logs().v('No more events found in the store. Request from server...');
         await room.requestHistory(
           historyCount: historyCount,
           onHistoryReceived: () {
             _collectHistoryUpdates = true;
           },
         );
-      try {
-        await Future.delayed(const Duration(seconds: 2));
-        _proccessHistoryUpdates();
+      }
     } finally {
       _collectHistoryUpdates = false;
       isRequestingHistory = false;
+      onUpdate?.call();
     }
   }
-  }
-
-  void _proccessHistoryUpdates() async {
-    _collectHistoryUpdates = false;
-    for (final update in _historyUpdates) {
-      _handleEventUpdate(await update.decrypt(room, store: true),
-          update: false);
-    }
-    _historyUpdates.clear();
-    if (onUpdate != null) onUpdate();
-  }
 
   Timeline({this.room, List<Event> events, this.onUpdate, this.onInsert})
       : events = events ?? [] {
@@ -247,12 +250,6 @@ class Timeline {
     try {
       if (eventUpdate.roomID != room.id) return;
 
-      if (eventUpdate.type == EventUpdateType.history &&
-          _collectHistoryUpdates) {
-        _historyUpdates.add(eventUpdate);
-        return;
-      }
-
       if (eventUpdate.type != EventUpdateType.timeline &&
           eventUpdate.type != EventUpdateType.history) {
         return;
@@ -318,7 +315,7 @@ class Timeline {
           if (onInsert != null) onInsert(0);
         }
       }
-      if (update) {
+      if (update && !_collectHistoryUpdates) {
         if (onUpdate != null) onUpdate();
       }
     } catch (e, s) {

test/fake_matrix_api.dart

@@ -1337,7 +1337,7 @@ class FakeMatrixApi extends MockClient {
           (var req) => messagesResponse,
       '/client/r0/rooms/!localpart%3Aserver.abc/messages?from=&dir=b&limit=10&filter=%7B%22lazy_load_members%22%3Atrue%7D':
           (var req) => messagesResponse,
-      '/client/r0/rooms/!1234%3Aexample.com/messages?from=1234&dir=b&limit=100&filter=%7B%22lazy_load_members%22%3Atrue%7D':
+      '/client/r0/rooms/!1234%3Aexample.com/messages?from=1234&dir=b&limit=30&filter=%7B%22lazy_load_members%22%3Atrue%7D':
           (var req) => messagesResponse,
       '/client/versions': (var req) => {
             'versions': [