3 files changed, 18 insertions, 6 deletions
diff --git a/src/timeline/RoomlistModel.cpp b/src/timeline/RoomlistModel.cpp
index 1e0b4c23..972f061d 100644
--- a/src/timeline/RoomlistModel.cpp
+++ b/src/timeline/RoomlistModel.cpp
@@ -121,7 +121,7 @@ RoomlistModel::data(const QModelIndex &index, int role) const
             case Roles::Time:
                 return room->lastMessage().descriptiveTime;
             case Roles::Timestamp:
-                return QVariant{static_cast<quint64>(room->lastMessage().timestamp)};
+                return QVariant{static_cast<quint64>(room->lastMessageTimestamp())};
             case Roles::HasUnreadMessages:
                 return this->roomReadStatus.count(roomid) && this->roomReadStatus.at(roomid);
             case Roles::HasLoudNotification:
@@ -333,7 +333,7 @@ RoomlistModel::addRoom(const QString &room_id, bool suppressInsertNotification)
             emit totalUnreadMessageCountUpdated(total_unread_msgs);
         });
 
-        newRoom->updateLastMessage();
+        // newRoom->updateLastMessage();
 
         std::vector<QString> previewsToAdd;
         if (newRoom->isSpace()) {
diff --git a/src/timeline/TimelineModel.cpp b/src/timeline/TimelineModel.cpp
index 142ca793..578d63b7 100644
--- a/src/timeline/TimelineModel.cpp
+++ b/src/timeline/TimelineModel.cpp
@@ -353,14 +353,13 @@ TimelineModel::TimelineModel(TimelineViewManager *manager, QString room_id, QObj
   , manager_(manager)
   , permissions_{room_id_}
 {
-    lastMessage_.timestamp = 0;
-
     this->isEncrypted_ = cache::isRoomEncrypted(room_id_.toStdString());
 
     auto roomInfo            = cache::singleRoomInfo(room_id_.toStdString());
     this->isSpace_           = roomInfo.is_space;
     this->notification_count = roomInfo.notification_count;
     this->highlight_count    = roomInfo.highlight_count;
+    lastMessage_.timestamp   = roomInfo.approximate_last_modification_ts;
 
     // this connection will simplify adding the plainRoomNameChanged() signal everywhere that it
     // needs to be
@@ -1025,10 +1024,21 @@ isYourJoin(const mtx::events::Event<T> &)
     return false;
 }
 
+DescInfo
+TimelineModel::lastMessage() const
+{
+    if (lastMessage_.event_id.isEmpty())
+        QTimer::singleShot(0, this, &TimelineModel::updateLastMessage);
+
+    return lastMessage_;
+}
+
 void
 TimelineModel::updateLastMessage()
 {
-    for (auto it = events.size() - 1; it >= 0; --it) {
+    // only try to generate a preview for the last 1000 messages
+    auto end = std::max(events.size() - 1001, 0);
+    for (auto it = events.size() - 1; it >= end; --it) {
         auto event = events.get(it, decryptDescription);
         if (!event)
             continue;
diff --git a/src/timeline/TimelineModel.h b/src/timeline/TimelineModel.h
index dae64094..ec9a34f1 100644
--- a/src/timeline/TimelineModel.h
+++ b/src/timeline/TimelineModel.h
@@ -311,7 +311,9 @@ public:
     void sendMessageEvent(const T &content, mtx::events::EventType eventType);
     RelatedInfo relatedInfo(const QString &id);
 
-    DescInfo lastMessage() const { return lastMessage_; }
+    DescInfo lastMessage() const;
+    uint64_t lastMessageTimestamp() const { return lastMessage_.timestamp; }
+
     bool isSpace() const { return isSpace_; }
     bool isEncrypted() const { return isEncrypted_; }
     crypto::Trust trustlevel() const;