From 382111583d132a2999ea369b18ae315998441e39 Mon Sep 17 00:00:00 2001
From: Gisle Aune <dev@gisle.me>
Date: Fri, 19 Aug 2022 23:14:06 +0200
Subject: [PATCH] add privileged service subscription, which grants first look
 at all events but no bus access in handling.

---
 bus.go              | 25 ++++++++++++++++++++++---
 cmd/bustest/main.go | 18 ++----------------
 2 files changed, 24 insertions(+), 19 deletions(-)

diff --git a/bus.go b/bus.go
index 7d05dcf..17c1d78 100644
--- a/bus.go
+++ b/bus.go
@@ -24,9 +24,10 @@ type Command interface {
 }
 
 type EventBus struct {
-	mu        sync.Mutex
-	listeners []*serviceListener
-	signal    chan struct{}
+	mu             sync.Mutex
+	listeners      []*serviceListener
+	privilegedList []ActiveService
+	signal         chan struct{}
 }
 
 // JoinCallback joins the event bus for a moment.
@@ -51,6 +52,15 @@ func (b *EventBus) Join(service Service) {
 	b.mu.Unlock()
 }
 
+// JoinPrivileged will add the services to a list that gets first look at
+// all events, but they are not allowed to issue any commands. This is for
+// things that cannot have eventual consistency.
+func (b *EventBus) JoinPrivileged(service ActiveService) {
+	b.mu.Lock()
+	b.privilegedList = append(b.privilegedList, service)
+	b.mu.Unlock()
+}
+
 func (b *EventBus) RunCommand(command Command) {
 	fmt.Println("[COMMAND]", command.CommandDescription())
 	b.send(serviceMessage{command: command})
@@ -65,6 +75,15 @@ func (b *EventBus) send(message serviceMessage) {
 	b.mu.Lock()
 	defer b.mu.Unlock()
 
+	for _, service := range b.privilegedList {
+		if message.command != nil {
+			service.HandleCommand(nil, message.command)
+		}
+		if message.event != nil {
+			service.HandleEvent(nil, message.event)
+		}
+	}
+
 	deleteList := make([]int, 0, 0)
 	for i, listener := range b.listeners {
 		if !listener.service.Active() {
diff --git a/cmd/bustest/main.go b/cmd/bustest/main.go
index b841eac..1d235b7 100644
--- a/cmd/bustest/main.go
+++ b/cmd/bustest/main.go
@@ -20,12 +20,10 @@ func main() {
 	resolver := services.NewResolver()
 	sceneMap := services.NewSceneMap(resolver)
 
-	bus.Join(resolver)
-	bus.Join(sceneMap)
+	bus.JoinPrivileged(resolver)
+	bus.JoinPrivileged(sceneMap)
 	bus.Join(services.NewEffectEnforcer(resolver, sceneMap))
 
-	time.Sleep(time.Millisecond)
-
 	bus.RunEvent(events.Connected{Prefix: "nanoleaf:10.80.1.11"})
 
 	numbers := []int{5, 2, 3, 1, 4}
@@ -39,22 +37,16 @@ func main() {
 		})
 	}
 
-	time.Sleep(time.Millisecond)
-
 	bus.RunCommand(commands.ReplaceScene{
 		Match:   "lucifer:name:Hex*",
 		SceneID: 7,
 	})
 
-	time.Sleep(time.Millisecond)
-
 	bus.RunCommand(commands.AddAlias{
 		Match: "nanoleaf:10.80.1.{11,7,16,5}:*",
 		Alias: "lucifer:tag:Magic Lamps",
 	})
 
-	time.Sleep(time.Millisecond)
-
 	for i, id := range []string{"40e5", "dead", "beef", "cafe", "1337"} {
 		bus.RunEvent(events.HardwareState{
 			ID:           "nanoleaf:10.80.1.11:" + id,
@@ -65,8 +57,6 @@ func main() {
 		})
 	}
 
-	time.Sleep(time.Millisecond)
-
 	bus.RunEvent(events.ExternalEvent{
 		Kind: "weather",
 		Values: map[string]string{
@@ -76,8 +66,6 @@ func main() {
 		},
 	})
 
-	time.Sleep(time.Millisecond)
-
 	c1 := gentools.Ptr(color.MustParse("rgb:#ff0000"))
 	c2 := gentools.Ptr(color.MustParse("rgb:#00ff00"))
 	bus.RunCommand(commands.Assign{
@@ -100,8 +88,6 @@ func main() {
 		},
 	})
 
-	time.Sleep(time.Millisecond * 100)
-
 	log.Println("Search \"**:Hexagon {1,5,6}\"")
 	for _, dev := range resolver.Resolve("lucifer:name:Hexagon {1,5,6}") {
 		log.Println("- ID:", dev.ID)