Implemented unread messages indication on the lib side

The implementation allows further extension to actually counting unread messages (in their Room::isEventNotable() sense - see the code) but so far just replicates what Quaternion previously provided. The only difference from the Quaternion implementation is that last own message is not marked as read immediately - so that we can allow the local user to send messages while staying with the read marker well above. This implies, though, that the read marker won't reset to the timeline bottom at any movement of the user - rather that it resets to the bottom of the current view (which is the ultimately correct behaviour, anyway).

2 files changed, 64 insertions, 14 deletions

diff --git a/room.cpp b/room.cpp
index c2a1ce70..fa919f61 100644
--- a/room.cpp
+++ b/room.cpp
@@ -49,7 +49,7 @@ class Room::Private
 
         Private(Connection* c, const QString& id_)
             : q(nullptr), connection(c), id(id_), joinState(JoinState::Join)
-            , roomMessagesJob(nullptr)
+            , unreadMessages(false), roomMessagesJob(nullptr)
         { }
 
         Room* q;
@@ -68,6 +68,7 @@ class Room::Private
         QString displayname;
         QString topic;
         JoinState joinState;
+        bool unreadMessages;
         int highlightCount;
         int notificationCount;
         members_map_t membersMap;
@@ -90,6 +91,7 @@ class Room::Private
 
         void getPreviousContent();
 
+        bool isEventNotable(const Event* e) const;
     private:
         QString calculateDisplayname() const;
         QString roomNameFromMemberNames(const QList<User*>& userlist) const;
@@ -169,30 +171,46 @@ void Room::setLastReadEvent(User* user, QString eventId)
     emit lastReadEventChanged(user);
 }
 
-bool Room::promoteReadMarker(User* user, QString eventId)
+bool Room::promoteReadMarker(QString newLastReadEventId)
 {
-    // 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);
+    User* localUser = connection()->user();
+    QString prevLastReadId = lastReadEvent(localUser);
+    int stillUnreadMessagesCount = 0;
     // Older Qt doesn't provide rbegin()/rend() for Qt containers
     for (auto it = messageEvents().end(); it != messageEvents().begin();)
     {
         --it;
+        // Check that the new read event is not before the previously set - only
+        // allow the read marker to move down the timeline, not up.
         if (prevLastReadId == (*it)->id())
-            return false;
-        if (eventId == (*it)->id())
+            break;
+
+        // Found the message to mark as read; for the local user,
+        // if we don't have other notable events below this one, reset unreadMessages
+        if (newLastReadEventId == (*it)->id())
         {
-            setLastReadEvent(user, eventId);
-            return true;
+            setLastReadEvent(localUser, newLastReadEventId);
+            break;
         }
+
+        // Detect events "notable" for the local user so that we can properly
+        // set unreadMessages
+        stillUnreadMessagesCount += d->isEventNotable(*it);
     }
-    return false;
+    if( d->unreadMessages && stillUnreadMessagesCount == 0)
+    {
+        d->unreadMessages = false;
+        emit unreadMessagesChanged(this);
+    }
+    qDebug() << "Room" << displayName()
+             << ": still" << stillUnreadMessagesCount << "unread message(s)";
+    return newLastReadEventId.isEmpty() || lastReadEvent(localUser) == newLastReadEventId;
 }
 
 void Room::markMessagesAsRead(Timeline::const_iterator last)
 {
     QString prevLastReadId = lastReadEvent(connection()->user());
-    if ( !promoteReadMarker(connection()->user(), (*last)->id()) )
+    if ( !promoteReadMarker( (*last)->id()) )
         return;
 
     // We shouldn't send read receipts for messages from the local user - so
@@ -216,6 +234,11 @@ void Room::markMessagesAsRead()
         markMessagesAsRead(messageEvents().end() - 1);
 }
 
+bool Room::hasUnreadMessages()
+{
+    return d->unreadMessages;
+}
+
 QString Room::lastReadEvent(User* user)
 {
     return d->lastReadEvent.value(user);
@@ -441,10 +464,29 @@ void Room::addNewMessageEvents(const Events& events)
     emit addedMessages();
 }
 
+bool Room::Private::isEventNotable(const Event* e) const
+{
+    return e->senderId() != connection->userId() &&
+            e->type() == EventType::RoomMessage;
+}
+
 void Room::doAddNewMessageEvents(const Events& events)
 {
     d->messageEvents.reserve(d->messageEvents.size() + events.size());
-    std::copy(events.begin(), events.end(), std::back_inserter(d->messageEvents));
+    int newMessages = 0;
+
+    for (auto e: events)
+    {
+        d->messageEvents.push_back(e);
+        newMessages += d->isEventNotable(e);
+    }
+
+    if( !d->unreadMessages && newMessages > 0)
+    {
+        d->unreadMessages = true;
+        emit unreadMessagesChanged(this);
+        qDebug() << "Room" << displayName() << ": unread messages";
+    }
 }
 
 void Room::addHistoricalMessageEvents(const Events& events)
@@ -537,7 +579,12 @@ void Room::processEphemeralEvent(Event* event)
             for( const Receipt& r: receipts )
             {
                 if (auto m = d->member(r.userId))
-                    promoteReadMarker(m, eventId);
+                {
+                    if (m == connection()->user())
+                        promoteReadMarker(eventId);
+                    else
+                        setLastReadEvent(m, eventId);
+                }
             }
         }
     }
diff --git a/room.h b/room.h
index fb3212e9..38435e95 100644
--- a/room.h
+++ b/room.h
@@ -85,6 +85,8 @@ namespace QMatrixClient
              */
             Q_INVOKABLE void markMessagesAsRead();
 
+            Q_INVOKABLE bool hasUnreadMessages();
+
             Q_INVOKABLE int notificationCount() const;
             Q_INVOKABLE void resetNotificationCount();
             Q_INVOKABLE int highlightCount() const;
@@ -116,6 +118,7 @@ namespace QMatrixClient
             void highlightCountChanged(Room* room);
             void notificationCountChanged(Room* room);
             void lastReadEventChanged(User* user);
+            void unreadMessagesChanged(Room* room);
 
         protected:
             Connection* connection() const;
@@ -124,7 +127,7 @@ namespace QMatrixClient
             virtual void processStateEvents(const Events& events);
             virtual void processEphemeralEvent(Event* event);
 
-            bool promoteReadMarker(User* user, QString eventId);
+            bool promoteReadMarker(QString newLastReadEventId);
 
         private:
             class Private;