some more work.

app/services/publisher/scene.go

@@ -17,10 +17,25 @@ type Scene struct {
 	due bool
 }
 
+// UpdateScene updates the scene data and re-seats all devices.
 func (s *Scene) UpdateScene(data models.Scene) {
+	devices := make([]models.Device, 0, 16)
 
+	for ri, list := range s.roleList {
+		for _, device := range list {
+			devices = append(devices, device)
+			s.roleMap[device.ID] = -1
+		}
+	}
+
+	s.roleList = map[int][]models.Device {-1: devices}
+
+	for _, device := range append(devices[:0:0], devices...) {
+		s.UpsertDevice(device)
+	}
 }
 
+// UpsertDevice moves the device if neccesary and updates its state.
 func (s *Scene) UpsertDevice(device models.Device) {
 	if s.data == nil {
 		s.roleMap[device.ID] = -1
@@ -56,6 +71,7 @@ func (s *Scene) UpsertDevice(device models.Device) {
 	s.data.Roles[newIndex].ApplyOrder(s.roleList[newIndex])
 }
 
+// RemoveDevice finds and remove a device. It's a noop if the device does not exist in this scene.
 func (s *Scene) RemoveDevice(device models.Device) {
 	roleIndex, hasRoleIndex := s.roleMap[device.ID]
 	if !hasRoleIndex {
@@ -68,8 +84,11 @@ func (s *Scene) RemoveDevice(device models.Device) {
 			break
 		}
 	}
+
+	delete(s.roleMap, device.ID)
 }
 
+// Run runs the scene
 func (s *Scene) Run() []models.Device {
 	if s.data == nil {
 		return []models.Device{}