added last seen display info in circles to help debugging auto-cleaning of circles

libretroshare/src/gxs/rsgenexchange.cc

@@ -1381,6 +1381,11 @@ bool RsGenExchange::getGroupMeta(const uint32_t &token, std::list<RsGroupMetaDat
 			m.mVisibleMsgCount = 0 ;
         }
 
+        // We could save this in the net service, but it's a bit more than that since some services have
+        // specific usage footprints for their groups.
+
+        m.mLastSeen = (IS_GROUP_SUBSCRIBED(gMeta.mSubscribeFlags)) ? time(nullptr) : service_getLastGroupUsageTs(gMeta.mGroupId);
+
 		groupInfo.push_back(m);
 	}
 

libretroshare/src/gxs/rsgenexchange.h

@@ -666,7 +666,7 @@ protected:
      * 			that the group is always in use.
      */
     virtual bool service_checkIfGroupIsStillUsed(const RsGxsGrpMetaData& /* meta */) { return true; }	// see RsGenExchange
-
+    virtual rstime_t service_getLastGroupUsageTs(const RsGxsGroupId&) { return 0; }
 public:
 
     /*!

libretroshare/src/retroshare/rsgxsifacetypes.h

@@ -91,6 +91,7 @@ struct RsGroupMetaData : RsSerializable
     uint32_t    mPop; 			   // Popularity = number of friend subscribers
     uint32_t    mVisibleMsgCount;  // Max messages reported by friends
     rstime_t    mLastPost; 		   // Timestamp for last message. Not used yet.
+    rstime_t    mLastSeen; 		   // Last time the group was advertised by friends.
 
     uint32_t    mGroupStatus;
 

libretroshare/src/services/p3gxscircles.cc

@@ -1700,6 +1700,20 @@ bool p3GxsCircles::locked_checkCircleCacheForAutoSubscribe(RsGxsCircleCache& cac
     return true;
 }
 
+rstime_t p3GxsCircles::service_getLastGroupUsageTs(const RsGxsGroupId& gid)
+{
+    rstime_t now = time(nullptr);
+
+    RS_STACK_MUTEX(mKnownCirclesMtx);
+
+    auto it = mKnownCircles.find(gid);
+    bool unknown_posted = (it == mKnownCircles.end());
+
+    if(unknown_posted)
+        return now;
+    else
+        return it->second;
+}
 bool p3GxsCircles::service_checkIfGroupIsStillUsed(const RsGxsGrpMetaData& meta)
 {
 #ifdef GXSFORUMS_CHANNELS

libretroshare/src/services/p3gxscircles.h

@@ -290,6 +290,7 @@ public:
 	virtual void updateGroup(uint32_t &token, RsGxsCircleGroup &group) override;
 
 	virtual bool service_checkIfGroupIsStillUsed(const RsGxsGrpMetaData& meta) override;
+    virtual rstime_t service_getLastGroupUsageTs(const RsGxsGroupId&) override;
 
 	/* membership management for external circles */
 

retroshare-gui/src/gui/Identity/IdDialog.cpp

@@ -695,7 +695,12 @@ void IdDialog::loadCircles(const std::list<RsGroupMetaData>& groupInfo)
 		if(am_I_subscribed)
 			tooltip += tr("subscribed (Receive/forward membership requests from others and invite list).") ;
 		else
+        {
+            if(vit->mLastSeen>0)
+                tooltip += tr("unsubscribed (Only receive invite list). Last seen: %1 days ago.").arg( (time(nullptr)-vit->mLastSeen)/86400 );
+            else
                 tooltip += tr("unsubscribed (Only receive invite list).");
+        }
 
 		tooltip += "\n"+tr("Your status: ") ;