MangaPresenter: Fix state updates when opening a new manga entry (#7379)

(cherry picked from commit 0e0c1dcdc5f42b0a63d5b865c9aba29db4ab18a6)

# Conflicts:
#	app/src/main/java/eu/kanade/tachiyomi/ui/manga/MangaPresenter.kt

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

@@ -32,7 +32,6 @@ import eu.kanade.tachiyomi.data.download.DownloadManager
 import eu.kanade.tachiyomi.data.download.model.Download
 import eu.kanade.tachiyomi.data.library.CustomMangaManager
 import eu.kanade.tachiyomi.data.preference.PreferencesHelper
-import eu.kanade.tachiyomi.data.saver.ImageSaver
 import eu.kanade.tachiyomi.data.track.EnhancedTrackService
 import eu.kanade.tachiyomi.data.track.TrackManager
 import eu.kanade.tachiyomi.data.track.TrackService
@@ -84,6 +83,7 @@ import kotlinx.coroutines.flow.collectLatest
 import kotlinx.coroutines.flow.combine
 import kotlinx.coroutines.flow.launchIn
 import kotlinx.coroutines.flow.onEach
+import kotlinx.coroutines.flow.update
 import kotlinx.coroutines.supervisorScope
 import kotlinx.coroutines.withContext
 import logcat.LogPriority
@@ -152,8 +152,6 @@ class MangaPresenter(
 
     private val loggedServices by lazy { trackManager.services.filter { it.isLogged } }
 
-    private val imageSaver: ImageSaver by injectLazy()
-
     private var trackSubscription: Subscription? = null
     private var searchTrackerJob: Job? = null
     private var refreshTrackersJob: Job? = null
@@ -194,6 +192,13 @@ class MangaPresenter(
             this(pair.first, pair.second, flatMetadata)
     }
 
+    /**
+     * Helper function to update the UI state only if it's currently in success state
+     */
+    private fun updateSuccessState(func: (MangaScreenState.Success) -> MangaScreenState.Success) {
+        _state.update { if (it is MangaScreenState.Success) func(it) else it }
+    }
+
     override fun onCreate(savedState: Bundle?) {
         super.onCreate(savedState)
 
@@ -253,8 +258,8 @@ class MangaPresenter(
                 // SY <--
                 .collectLatest { (manga, chapters, flatMetadata, mergedData) ->
                     val chapterItems = chapters.toChapterItems(manga, mergedData)
-                    val currentState = _state.value
+                    _state.update { currentState ->
-                    _state.value = when (currentState) {
+                        when (currentState) {
                             // Initialize success state
                             MangaScreenState.Loading -> {
                                 val source = Injekt.get<SourceManager>().getOrStub(manga.source)
@@ -297,6 +302,7 @@ class MangaPresenter(
                                 // SY <--
                             )
                         }
+                    }
 
                     fetchTrackers()
                     observeDownloads()
@@ -309,17 +315,13 @@ class MangaPresenter(
 
         preferences.incognitoMode()
             .asImmediateFlow { incognito ->
-                successState?.let {
+                updateSuccessState { it.copy(isIncognitoMode = incognito) }
-                    _state.value = it.copy(isIncognitoMode = incognito)
-                }
             }
             .launchIn(presenterScope)
 
         preferences.downloadedOnly()
             .asImmediateFlow { downloadedOnly ->
-                successState?.let {
+                updateSuccessState { it.copy(isDownloadedOnlyMode = downloadedOnly) }
-                    _state.value = it.copy(isDownloadedOnlyMode = downloadedOnly)
-                }
             }
             .launchIn(presenterScope)
     }
@@ -353,17 +355,18 @@ class MangaPresenter(
      */
     private fun fetchMangaFromSource(manualFetch: Boolean = false) {
         if (fetchMangaJob?.isActive == true) return
-        val successState = successState ?: return
         fetchMangaJob = presenterScope.launchIO {
-            _state.value = successState.copy(isRefreshingInfo = true)
+            updateSuccessState { it.copy(isRefreshingInfo = true) }
             try {
-                val networkManga = successState.source.getMangaDetails(successState.manga.toMangaInfo())
+                successState?.let {
-                updateManga.awaitUpdateFromSource(successState.manga, networkManga, manualFetch)
+                    val networkManga = it.source.getMangaDetails(it.manga.toMangaInfo())
+                    updateManga.awaitUpdateFromSource(it.manga, networkManga, manualFetch)
+                }
             } catch (e: Throwable) {
                 this@MangaPresenter.xLogE("Error getting manga details", e)
                 withUIContext { view?.onFetchMangaInfoError(e) }
             }
-            _state.value = successState.copy(isRefreshingInfo = false)
+            updateSuccessState { it.copy(isRefreshingInfo = false) }
         }
     }
 
@@ -417,7 +420,9 @@ class MangaPresenter(
             manga = manga.copy()
         }
 
-        _state.value = state.copy(manga = manga)
+        updateSuccessState { successState ->
+            successState.copy(manga = manga)
+        }
     }
 
     suspend fun smartSearchMerge(context: Context, manga: DomainManga, originalMangaId: Long): Manga {
@@ -750,15 +755,16 @@ class MangaPresenter(
     }
 
     private fun updateDownloadState(download: Download) {
-        val successState = successState ?: return
+        updateSuccessState { successState ->
             val modifiedIndex = successState.chapters.indexOfFirst { it.chapter.id == download.chapter.id }
-        if (modifiedIndex >= 0) {
+            if (modifiedIndex < 0) return@updateSuccessState successState
+
             val newChapters = successState.chapters.toMutableList().apply {
                 val item = removeAt(modifiedIndex)
                     .copy(downloadState = download.status, downloadProgress = download.progress)
                 add(modifiedIndex, item)
             }
-            _state.value = successState.copy(chapters = newChapters)
+            successState.copy(chapters = newChapters)
         }
     }
 
@@ -794,11 +800,10 @@ class MangaPresenter(
      */
     private fun fetchChaptersFromSource(manualFetch: Boolean = false) {
         if (fetchChaptersJob?.isActive == true) return
-        val successState = successState ?: return
-
         fetchChaptersJob = presenterScope.launchIO {
-            _state.value = successState.copy(isRefreshingChapter = true)
+            updateSuccessState { it.copy(isRefreshingChapter = true) }
             try {
+                successState?.let { successState ->
                     if (successState.source !is MergedSource) {
                         val chapters = successState.source.getChapterList(successState.manga.toMangaInfo())
                             .map { it.toSChapter() }
@@ -815,11 +820,13 @@ class MangaPresenter(
                         }
                     } else {
                         successState.source.fetchChaptersForMergedManga(successState.manga, manualFetch, true, dedupe)
+                        Unit
+                    }
                 }
             } catch (e: Throwable) {
                 withUIContext { view?.onFetchChaptersError(e) }
             }
-            _state.value = successState.copy(isRefreshingChapter = false)
+            updateSuccessState { it.copy(isRefreshingChapter = false) }
         }
     }
 
@@ -926,15 +933,15 @@ class MangaPresenter(
      * @param chapters the list of chapters to delete.
      */
     fun deleteChapters(chapters: List<DomainChapter>) {
-        val successState = successState ?: return
         launchIO {
             val chapters2 = chapters.map { it.toDbChapter() }
             try {
+                updateSuccessState { successState ->
                     val deletedIds = downloadManager
                         .deleteChapters(chapters2, successState.manga.toDbManga(), successState.source)
                         .map { it.id }
                     val deletedChapters = successState.chapters.filter { deletedIds.contains(it.chapter.id) }
-                if (deletedChapters.isEmpty()) return@launchIO
+                    if (deletedChapters.isEmpty()) return@updateSuccessState successState
 
                     // TODO: Don't do this fake status update
                     val newChapters = successState.chapters.toMutableList().apply {
@@ -945,7 +952,8 @@ class MangaPresenter(
                             add(index, toAdd)
                         }
                     }
-                _state.value = successState.copy(chapters = newChapters)
+                    successState.copy(chapters = newChapters)
+                }
             } catch (e: Throwable) {
                 logcat(LogPriority.ERROR, e)
             }