fix: harden group lifecycle and registration writes

server/calls.go

@@ -298,6 +298,24 @@ func callContentString(content any, key string) string {
 	return callPayloadString(content, key)
 }
 
+func normalizeCallEvent(event string) string {
+	switch strings.ToLower(strings.TrimSpace(event)) {
+	case "hangup", "hang_up", "hang-up", "finish", "finished", "end", "ended", "disconnect", "disconnected":
+		return constCallEventHangUp
+	default:
+		return strings.TrimSpace(event)
+	}
+}
+
+func isDetachedCallEvent(event string) bool {
+	switch normalizeCallEvent(event) {
+	case constCallEventRinging, constCallEventHangUp, constCallEventAccept:
+		return true
+	default:
+		return false
+	}
+}
+
 func (call *videoCall) matchesPayload(payload any) bool {
 	payloadCallID := callPayloadString(payload, "callId")
 	return payloadCallID == "" || payloadCallID == call.callID
@@ -536,7 +554,8 @@ func (t *Topic) handleCallEvent(msg *ClientComMessage) {
 		return
 	}
 
-	switch call.Event {
+	event := normalizeCallEvent(call.Event)
+	switch event {
 	case constCallEventRinging, constCallEventAccept:
 		// Invariants:
 		// 1. Call has been initiated but not been established yet.
@@ -554,10 +573,10 @@ func (t *Topic) handleCallEvent(msg *ClientComMessage) {
 			return
 		}
 		// Prepare a {info} message to forward to the call originator.
-		forwardMsg := t.currentCall.infoMessage(call.Event)
+		forwardMsg := t.currentCall.infoMessage(event)
 		forwardMsg.Info.From = msg.AsUser
 		forwardMsg.Info.Topic = t.original(originatorUid)
-		if call.Event == constCallEventAccept {
+		if event == constCallEventAccept {
 			// The call has been accepted.
 			// Send a replacement {data} message to the topic.
 			msgCopy := *msg
@@ -582,7 +601,7 @@ func (t *Topic) handleCallEvent(msg *ClientComMessage) {
 			t.auditCallAccept(t.currentCall, t.currentCall.acceptedAt)
 
 			// Notify other clients that the call has been accepted.
-			t.infoCallSubsOffline(msg.AsUser, asUid, call.Event, t.currentCall.seq, call.Payload, msg.sess.sid, false)
+			t.infoCallSubsOffline(msg.AsUser, asUid, event, t.currentCall.seq, call.Payload, msg.sess.sid, false)
 			t.callEstablishmentTimer.Stop()
 		}
 		originator.queueOut(forwardMsg)