state-stream: fix storing/restoring notification volume

We apparently store things in the <media-class>:<key>:<value>
format, while pipewire-pulse expects <media-class>.<key>:<value>
and this detail was missed in the latest refactoring.

It also seems that I forgot to ensure that restoring this metadata
key worked. The hook was there, but not registered.
Remove the hook and directly populate the metadata object when
it is activated, as it seems simpler.

Fixes: #604

src/scripts/node/state-stream.lua

@@ -264,32 +264,25 @@ store_stream_target_hook = SimpleEventHook {
   end
 }
 
--- track route-settings metadata changes
-route_settings_metadata_added_hook = SimpleEventHook {
-  name = "node/route-settings-metadata-added",
-  interests = {
-    EventInterest {
-      Constraint { "event.type", "=", "metadata-added" },
-      Constraint { "metadata.name", "=", "route-settings" },
-    },
-  },
-  execute = function (event)
-    local metadata = event:get_subject ()
+-- populate route-settings metadata
+function populateMetadata (metadata)
+  -- copy state into the metadata
+  local key = "Output/Audio:media.role:Notification"
+  local p = getStoredStreamProps (key)
+  if p then
+    p.channels = p.channelMap and Json.Array (p.channelMap)
+    p.volumes = p.channelVolumes and Json.Array (p.channelVolumes)
+    p.channelMap = nil
+    p.channelVolumes = nil
+    p.target = nil
 
-    -- copy state into the metadata
-    local key = "Output/Audio:media.role:Notification"
-    local p = getStoredStreamProps (key)
-    if p then
-      p.channels = p.channelMap and Json.Array (p.channelMap)
-      p.volumes = p.channelVolumes and Json.Array (p.channelVolumes)
-      p.channelMap = nil
-      p.channelVolumes = nil
-      p.target = nil
-      metadata:set (0, "restore.stream." .. key, "Spa:String:JSON",
-          Json.Object (p):to_string ())
-    end
+    -- pipewire-pulse expects the key to be
+    -- "restore.stream.Output/Audio.media.role:Notification"
+    key = string.gsub (key, ":", ".", 1);
+    metadata:set (0, "restore.stream." .. key, "Spa:String:JSON",
+        Json.Object (p):to_string ())
   end
-}
+end
 
 -- track route-settings metadata changes
 route_settings_metadata_changed_hook = SimpleEventHook {
@@ -299,7 +292,7 @@ route_settings_metadata_changed_hook = SimpleEventHook {
       Constraint { "event.type", "=", "metadata-changed" },
       Constraint { "metadata.name", "=", "route-settings" },
       Constraint { "event.subject.key", "=",
-          "restore.stream.Output/Audio:media.role:Notification" },
+          "restore.stream.Output/Audio.media.role:Notification" },
       Constraint { "event.subject.spa_type", "=", "Spa:String:JSON" },
       Constraint { "event.subject.value", "is-present" },
     },
@@ -316,6 +309,8 @@ route_settings_metadata_changed_hook = SimpleEventHook {
     end
 
     local vparsed = json:parse ()
+
+    -- we store the key as "Output/Audio:media.role:Notification"
     local key = string.sub (key, string.len ("restore.stream.") + 1)
     key = string.gsub (key, "%.", ":", 1);
 
@@ -427,6 +422,8 @@ function toggleState (enable)
     rs_metadata:activate (Features.ALL, function (m, e)
       if e then
         log:warning ("failed to activate route-settings metadata: " .. tostring (e))
+      else
+        populateMetadata (m)
       end
     end)