Do not send user joined messages for already active users (#1416)

* Do not send user joined messages for active users

* Reduce from active within 10min to 5

core/chat/events.go

@@ -112,4 +112,5 @@ func (s *Server) userMessageSent(eventData chatClientEvent) {
 	SaveUserMessage(event)
 
 	eventData.client.MessageCount = eventData.client.MessageCount + 1
+	_lastSeenCache[event.User.ID] = time.Now()
 }

core/chat/server.go

@@ -20,6 +20,9 @@ import (
 
 var _server *Server
 
+// a map of user IDs and when they last were active.
+var _lastSeenCache = map[string]time.Time{}
+
 // Server represents an instance of the chat server.
 type Server struct {
 	mu                       sync.RWMutex
@@ -83,11 +86,18 @@ func (s *Server) Addclient(conn *websocket.Conn, user *user.User, accessToken st
 		ConnectedAt: time.Now(),
 	}
 
+	// Do not send user re-joined broadcast message if they've been active within 5 minutes.
+	shouldSendJoinedMessages := true
+	if previouslyLastSeen, ok := _lastSeenCache[user.ID]; ok && time.Since(previouslyLastSeen) < time.Minute*5 {
+		shouldSendJoinedMessages = false
+	}
+
 	s.mu.Lock()
 	{
 		client.id = s.seq
 		s.clients[client.id] = client
 		s.seq++
+		_lastSeenCache[user.ID] = time.Now()
 	}
 	s.mu.Unlock()
 
@@ -99,7 +109,9 @@ func (s *Server) Addclient(conn *websocket.Conn, user *user.User, accessToken st
 	client.sendConnectedClientInfo()
 
 	if getStatus().Online {
+		if shouldSendJoinedMessages {
 			s.sendUserJoinedMessage(client)
+		}
 		s.sendWelcomeMessageToClient(client)
 	}