invoiceregistry: extract dispatch to method

invoices/invoiceregistry.go

@@ -139,12 +139,27 @@ func (i *InvoiceRegistry) invoiceEventNotifier() {
 		// A sub-systems has just modified the invoice state, so we'll
 		// dispatch notifications to all registered clients.
 		case event := <-i.invoiceEvents:
+			i.dispatchToClients(event)
+
+		case <-i.quit:
+			return
+		}
+	}
+}
+
+// dispatchToClients passes the supplied event to all notification clients that
+// subscribed to all invoices. Add and settle indices are used to make sure that
+// clients don't receive duplicate or unwanted events.
+func (i *InvoiceRegistry) dispatchToClients(event *invoiceEvent) {
+	invoice := event.invoice
+
 	for clientID, client := range i.notificationClients {
 		// Before we dispatch this event, we'll check
 		// to ensure that this client hasn't already
 		// received this notification in order to
 		// ensure we don't duplicate any events.
-				invoice := event.invoice
+
+		// TODO(joostjager): Refactor switches.
 		switch {
 		// If we've already sent this settle event to
 		// the client, then we can skip this.
@@ -168,6 +183,7 @@ func (i *InvoiceRegistry) invoiceEventNotifier() {
 				"add_index=%v, new add event index=%v",
 				clientID, client.addIndex,
 				invoice.AddIndex)
+
 		case event.state == channeldb.ContractSettled &&
 			client.settleIndex+1 != invoice.SettleIndex:
 			log.Warnf("client=%v for invoice "+
@@ -186,25 +202,17 @@ func (i *InvoiceRegistry) invoiceEventNotifier() {
 			return
 		}
 
-				// Each time we send a notification to a
+		// Each time we send a notification to a client, we'll record
-				// client, we'll record the latest add/settle
+		// the latest add/settle index it has. We'll use this to ensure
-				// index it has. We'll use this to ensure we
+		// we don't send a notification twice, which can happen if a new
-				// don't send a notification twice, which can
+		// event is added while we're catching up a new client.
-				// happen if a new event is added while we're
-				// catching up a new client.
 		switch event.state {
 		case channeldb.ContractSettled:
 			client.settleIndex = invoice.SettleIndex
 		case channeldb.ContractOpen:
 			client.addIndex = invoice.AddIndex
 		default:
-					log.Errorf("unknown invoice "+
+			log.Errorf("unknown invoice state: %v", event.state)
-						"state: %v", event.state)
-				}
-			}
-
-		case <-i.quit:
-			return
 		}
 	}
 }