Cleanup MangaScreenModel successState usage (#9582)

* Refactor updateSuccessState

- Convert to inline function
- Use when for type safety if we add other MangaScreenState types

* Replace equivalent expressions with updateSuccessState

* Replace safe cast in MangaScreen

app/src/main/java/eu/kanade/tachiyomi/ui/manga/MangaScreen.kt

@@ -134,7 +134,7 @@ class MangaScreen(
         )
 
         val onDismissRequest = { screenModel.dismissDialog() }
-        when (val dialog = (state as? MangaScreenState.Success)?.dialog) {
+        when (val dialog = successState.dialog) {
             null -> {}
             is MangaInfoScreenModel.Dialog.ChangeCategory -> {
                 ChangeCategoryDialog(

app/src/main/java/eu/kanade/tachiyomi/ui/manga/MangaScreenModel.kt

@@ -135,8 +135,13 @@ class MangaInfoScreenModel(
     /**
      * Helper function to update the UI state only if it's currently in success state
      */
-    private fun updateSuccessState(func: (MangaScreenState.Success) -> MangaScreenState.Success) {
+    private inline fun updateSuccessState(func: (MangaScreenState.Success) -> MangaScreenState.Success) {
-        mutableState.update { if (it is MangaScreenState.Success) func(it) else it }
+        mutableState.update {
+            when (it) {
+                MangaScreenState.Loading -> it
+                is MangaScreenState.Success -> func(it)
+            }
+        }
     }
 
     init {
@@ -278,12 +283,7 @@ class MangaInfoScreenModel(
                     val duplicate = getDuplicateLibraryManga.await(manga.title)
 
                     if (duplicate != null) {
-                        mutableState.update { state ->
+                        updateSuccessState { it.copy(dialog = Dialog.DuplicateManga(manga, duplicate)) }
-                            when (state) {
-                                MangaScreenState.Loading -> state
-                                is MangaScreenState.Success -> state.copy(dialog = Dialog.DuplicateManga(manga, duplicate))
-                            }
-                        }
                         return@launchIO
                     }
                 }
@@ -340,10 +340,8 @@ class MangaInfoScreenModel(
         coroutineScope.launch {
             val categories = getCategories()
             val selection = getMangaCategoryIds(manga)
-            mutableState.update { state ->
+            updateSuccessState { successState ->
-                when (state) {
+                successState.copy(
-                    MangaScreenState.Loading -> state
-                    is MangaScreenState.Success -> state.copy(
                     dialog = Dialog.ChangeCategory(
                         manga = manga,
                         initialSelection = categories.mapAsCheckboxState { it.id in selection },
@@ -352,7 +350,6 @@ class MangaInfoScreenModel(
             }
         }
     }
-    }
 
     /**
      * Returns true if the manga has any downloads.
@@ -954,52 +951,23 @@ class MangaInfoScreenModel(
     }
 
     fun dismissDialog() {
-        mutableState.update { state ->
+        updateSuccessState { it.copy(dialog = null) }
-            when (state) {
-                MangaScreenState.Loading -> state
-                is MangaScreenState.Success -> state.copy(dialog = null)
-            }
-        }
     }
 
     fun showDeleteChapterDialog(chapters: List<Chapter>) {
-        mutableState.update { state ->
+        updateSuccessState { it.copy(dialog = Dialog.DeleteChapters(chapters)) }
-            when (state) {
-                MangaScreenState.Loading -> state
-                is MangaScreenState.Success -> state.copy(dialog = Dialog.DeleteChapters(chapters))
-            }
-        }
     }
 
     fun showSettingsDialog() {
-        mutableState.update { state ->
+        updateSuccessState { it.copy(dialog = Dialog.SettingsSheet) }
-            when (state) {
-                MangaScreenState.Loading -> state
-                is MangaScreenState.Success -> state.copy(dialog = Dialog.SettingsSheet)
-            }
-        }
     }
 
     fun showTrackDialog() {
-        mutableState.update { state ->
+        updateSuccessState { it.copy(dialog = Dialog.TrackSheet) }
-            when (state) {
-                MangaScreenState.Loading -> state
-                is MangaScreenState.Success -> {
-                    state.copy(dialog = Dialog.TrackSheet)
-                }
-            }
-        }
     }
 
     fun showCoverDialog() {
-        mutableState.update { state ->
+        updateSuccessState { it.copy(dialog = Dialog.FullCover) }
-            when (state) {
-                MangaScreenState.Loading -> state
-                is MangaScreenState.Success -> {
-                    state.copy(dialog = Dialog.FullCover)
-                }
-            }
-        }
     }
 }