2 files changed, 70 insertions, 4 deletions

diff --git a/room.cpp b/room.cpp
index e07426a7..c2a1ce70 100644
--- a/room.cpp
+++ b/room.cpp
@@ -163,9 +163,57 @@ void Room::setJoinState(JoinState state)
     emit joinStateChanged(oldState, state);
 }
 
-void Room::markMessageAsRead(Event* event)
+void Room::setLastReadEvent(User* user, QString eventId)
 {
-    d->connection->postReceipt(this, event);
+    d->lastReadEvent.insert(user, eventId);
+    emit lastReadEventChanged(user);
+}
+
+bool Room::promoteReadMarker(User* user, QString eventId)
+{
+    // Check that the new read event is not before the previously set - only
+    // allow the read marker to move down the timeline, not up.
+    QString prevLastReadId = lastReadEvent(user);
+    // Older Qt doesn't provide rbegin()/rend() for Qt containers
+    for (auto it = messageEvents().end(); it != messageEvents().begin();)
+    {
+        --it;
+        if (prevLastReadId == (*it)->id())
+            return false;
+        if (eventId == (*it)->id())
+        {
+            setLastReadEvent(user, eventId);
+            return true;
+        }
+    }
+    return false;
+}
+
+void Room::markMessagesAsRead(Timeline::const_iterator last)
+{
+    QString prevLastReadId = lastReadEvent(connection()->user());
+    if ( !promoteReadMarker(connection()->user(), (*last)->id()) )
+        return;
+
+    // We shouldn't send read receipts for messages from the local user - so
+    // shift back (if necessary) to the nearest message not from the local user
+    // or the so far last read message, whichever comes first.
+    for (; (*last)->id() != prevLastReadId; --last)
+    {
+        if ((*last)->senderId() != connection()->userId())
+        {
+            d->connection->postReceipt(this, (*last));
+            break;
+        }
+        if (last == messageEvents().begin())
+            break;
+    }
+}
+
+void Room::markMessagesAsRead()
+{
+    if (!messageEvents().empty())
+        markMessagesAsRead(messageEvents().end() - 1);
 }
 
 QString Room::lastReadEvent(User* user)
@@ -489,7 +537,7 @@ void Room::processEphemeralEvent(Event* event)
             for( const Receipt& r: receipts )
             {
                 if (auto m = d->member(r.userId))
-                    d->lastReadEvent.insert(m, eventId);
+                    promoteReadMarker(m, eventId);
             }
         }
     }
diff --git a/room.h b/room.h
index 7266ae70..fb3212e9 100644
--- a/room.h
+++ b/room.h
@@ -69,8 +69,21 @@ namespace QMatrixClient
             Q_INVOKABLE void updateData(SyncRoomData& data );
             Q_INVOKABLE void setJoinState( JoinState state );
 
-            Q_INVOKABLE void markMessageAsRead( Event* event );
             Q_INVOKABLE QString lastReadEvent(User* user);
+            /**
+             * @brief Mark the message at the iterator as read
+             *
+             * Marks the message at the iterator as read; also posts a read
+             * receipt to the server either for this message or, if it's from
+             * the local user, for the nearest non-local message before.
+             */
+            Q_INVOKABLE void markMessagesAsRead(Timeline::const_iterator last);
+            /**
+             * @brief Mark the most recent message in the timeline as read
+             *
+             * This effectively marks everything in the room as read.
+             */
+            Q_INVOKABLE void markMessagesAsRead();
 
             Q_INVOKABLE int notificationCount() const;
             Q_INVOKABLE void resetNotificationCount();
@@ -102,6 +115,7 @@ namespace QMatrixClient
             void typingChanged();
             void highlightCountChanged(Room* room);
             void notificationCountChanged(Room* room);
+            void lastReadEventChanged(User* user);
 
         protected:
             Connection* connection() const;
@@ -110,12 +124,16 @@ namespace QMatrixClient
             virtual void processStateEvents(const Events& events);
             virtual void processEphemeralEvent(Event* event);
 
+            bool promoteReadMarker(User* user, QString eventId);
+
         private:
             class Private;
             Private* d;
 
             void addNewMessageEvents(const Events& events);
             void addHistoricalMessageEvents(const Events& events);
+
+            void setLastReadEvent(User* user, QString eventId);
     };
 }