Cleanup FavouriteStatusRouter stateFlow

app/src/main/java/com/hippo/ehviewer/FavouriteStatusRouter.kt

@@ -23,8 +23,8 @@ import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.channels.awaitClose
 import kotlinx.coroutines.flow.SharingStarted
 import kotlinx.coroutines.flow.callbackFlow
-import kotlinx.coroutines.flow.filter
 import kotlinx.coroutines.flow.shareIn
+import kotlinx.coroutines.flow.transform
 
 object FavouriteStatusRouter {
     private val idGenerator = IntIdGenerator(Settings.dataMapNextId)
@@ -79,5 +79,5 @@ object FavouriteStatusRouter {
         }
     }.shareIn(listenerScope, SharingStarted.Eagerly)
 
-    fun stateFlow(gid: Long) = globalFlow.filter { (gid1) -> gid1 == gid }
+    fun stateFlow(targetGid: Long) = globalFlow.transform { (gid, slot) -> if (targetGid == gid) emit(slot) }
 }

app/src/main/java/com/hippo/ehviewer/ui/scene/GalleryDetailScene.kt

@@ -693,9 +693,7 @@ class GalleryDetailScene : BaseScene() {
         ) {
             val favored by produceState(initialValue = false) {
                 value = galleryDetail.favoriteSlot != -2
-                FavouriteStatusRouter.stateFlow(galleryDetail.gid).collect { (_, slot) ->
-                    value = slot != -2
-                }
+                FavouriteStatusRouter.stateFlow(galleryDetail.gid).collect { value = it != -2 }
             }
             FilledTertiaryIconToggleButton(
                 checked = favored,