Fix loading empty manga

app/src/main/kotlin/org/koitharu/kotatsu/core/exceptions/EmptyMangaException.kt

@@ -0,0 +1,10 @@
+package org.koitharu.kotatsu.core.exceptions
+
+import org.koitharu.kotatsu.details.ui.pager.EmptyMangaReason
+import org.koitharu.kotatsu.parsers.model.Manga
+
+class EmptyMangaException(
+    val reason: EmptyMangaReason?,
+    val manga: Manga,
+    cause: Throwable?
+) : IllegalStateException(cause)

app/src/main/kotlin/org/koitharu/kotatsu/core/exceptions/resolve/ExceptionResolver.kt

@@ -16,6 +16,7 @@ import org.koitharu.kotatsu.R
 import org.koitharu.kotatsu.browser.BrowserActivity
 import org.koitharu.kotatsu.browser.cloudflare.CloudFlareActivity
 import org.koitharu.kotatsu.core.exceptions.CloudFlareProtectedException
+import org.koitharu.kotatsu.core.exceptions.EmptyMangaException
 import org.koitharu.kotatsu.core.exceptions.InteractiveActionRequiredException
 import org.koitharu.kotatsu.core.exceptions.ProxyConfigException
 import org.koitharu.kotatsu.core.exceptions.UnsupportedSourceException
@@ -25,6 +26,7 @@ import org.koitharu.kotatsu.core.prefs.AppSettings
 import org.koitharu.kotatsu.core.ui.dialog.buildAlertDialog
 import org.koitharu.kotatsu.core.util.ext.isHttpUrl
 import org.koitharu.kotatsu.core.util.ext.restartApplication
+import org.koitharu.kotatsu.details.ui.pager.EmptyMangaReason
 import org.koitharu.kotatsu.parsers.exception.AuthRequiredException
 import org.koitharu.kotatsu.parsers.exception.NotFoundException
 import org.koitharu.kotatsu.parsers.model.Manga
@@ -83,6 +85,16 @@ class ExceptionResolver private constructor(
                 false
             }
 
+            is EmptyMangaException -> {
+                when (e.reason) {
+                    EmptyMangaReason.NO_CHAPTERS -> openAlternatives(e.manga)
+                    EmptyMangaReason.LOADING_ERROR -> Unit
+                    EmptyMangaReason.RESTRICTED -> host.router.openBrowser(e.manga)
+                    else -> Unit
+                }
+                false
+            }
+
             is UnsupportedSourceException -> {
                 e.manga?.let { openAlternatives(it) }
                 false
@@ -229,6 +241,12 @@ class ExceptionResolver private constructor(
 
             is InteractiveActionRequiredException -> R.string._continue
 
+            is EmptyMangaException -> when (e.reason) {
+                EmptyMangaReason.RESTRICTED -> if (e.manga.publicUrl.isHttpUrl()) R.string.open_in_browser else 0
+                EmptyMangaReason.NO_CHAPTERS -> R.string.alternatives
+                else -> 0
+            }
+
             else -> 0
         }
 

app/src/main/kotlin/org/koitharu/kotatsu/core/nav/AppRouter.kt

@@ -215,6 +215,12 @@ class AppRouter private constructor(
         startActivity(browserIntent(contextOrNull() ?: return, url, source, title))
     }
 
+    fun openBrowser(manga: Manga) = openBrowser(
+        url = manga.publicUrl,
+        source = manga.source,
+        title = manga.title,
+    )
+
     fun openColorFilterConfig(manga: Manga, page: MangaPage) {
         startActivity(
             Intent(contextOrNull(), ColorFilterConfigActivity::class.java)

app/src/main/kotlin/org/koitharu/kotatsu/core/util/ext/Throwable.kt

@@ -22,6 +22,7 @@ import org.koitharu.kotatsu.core.exceptions.CaughtException
 import org.koitharu.kotatsu.core.exceptions.CloudFlareBlockedException
 import org.koitharu.kotatsu.core.exceptions.CloudFlareProtectedException
 import org.koitharu.kotatsu.core.exceptions.EmptyHistoryException
+import org.koitharu.kotatsu.core.exceptions.EmptyMangaException
 import org.koitharu.kotatsu.core.exceptions.IncompatiblePluginException
 import org.koitharu.kotatsu.core.exceptions.InteractiveActionRequiredException
 import org.koitharu.kotatsu.core.exceptions.NoDataReceivedException
@@ -103,6 +104,7 @@ private fun Throwable.getDisplayMessageOrNull(resources: Resources): String? = w
     is AccessDeniedException -> resources.getString(R.string.no_access_to_file)
     is NonFileUriException -> resources.getString(R.string.error_non_file_uri)
     is EmptyHistoryException -> resources.getString(R.string.history_is_empty)
+    is EmptyMangaException -> reason?.let { resources.getString(it.msgResId) } ?: cause?.getDisplayMessage(resources)
     is ProxyConfigException -> resources.getString(R.string.invalid_proxy_configuration)
     is SyncApiException,
     is ContentUnavailableException -> message
@@ -167,6 +169,8 @@ fun Throwable.getCauseUrl(): String? = when (this) {
     is CloudFlareProtectedException -> url
     is InteractiveActionRequiredException -> url
     is HttpStatusException -> url
+    is UnsupportedSourceException -> manga?.publicUrl?.takeIf { it.isHttpUrl() }
+    is EmptyMangaException -> manga.publicUrl.takeIf { it.isHttpUrl() }
     is HttpException -> (response.delegate as? Response)?.request?.url?.toString()
     else -> null
 }

app/src/main/kotlin/org/koitharu/kotatsu/details/data/MangaDetails.kt

@@ -7,6 +7,7 @@ import org.koitharu.kotatsu.core.ui.model.MangaOverride
 import org.koitharu.kotatsu.local.domain.model.LocalManga
 import org.koitharu.kotatsu.parsers.model.Manga
 import org.koitharu.kotatsu.parsers.model.MangaChapter
+import org.koitharu.kotatsu.parsers.model.MangaState
 import org.koitharu.kotatsu.parsers.util.ifNullOrEmpty
 import org.koitharu.kotatsu.parsers.util.nullIfEmpty
 import org.koitharu.kotatsu.reader.data.filterChapters
@@ -50,6 +51,9 @@ data class MangaDetails(
             .ifNullOrEmpty { localManga?.manga?.coverUrl }
             ?.nullIfEmpty()
 
+    val isRestricted: Boolean
+        get() = manga.state == MangaState.RESTRICTED
+
     private val mergedManga by lazy {
         if (localManga == null) {
             // fast path

app/src/main/kotlin/org/koitharu/kotatsu/reader/ui/ReaderViewModel.kt

@@ -29,6 +29,7 @@ import kotlinx.coroutines.plus
 import org.koitharu.kotatsu.R
 import org.koitharu.kotatsu.bookmarks.domain.Bookmark
 import org.koitharu.kotatsu.bookmarks.domain.BookmarksRepository
+import org.koitharu.kotatsu.core.exceptions.EmptyMangaException
 import org.koitharu.kotatsu.core.model.getPreferredBranch
 import org.koitharu.kotatsu.core.nav.MangaIntent
 import org.koitharu.kotatsu.core.nav.ReaderIntent
@@ -47,6 +48,7 @@ import org.koitharu.kotatsu.details.data.MangaDetails
 import org.koitharu.kotatsu.details.domain.DetailsInteractor
 import org.koitharu.kotatsu.details.domain.DetailsLoadUseCase
 import org.koitharu.kotatsu.details.ui.pager.ChaptersPagesViewModel
+import org.koitharu.kotatsu.details.ui.pager.EmptyMangaReason
 import org.koitharu.kotatsu.download.ui.worker.DownloadWorker
 import org.koitharu.kotatsu.history.data.HistoryRepository
 import org.koitharu.kotatsu.history.domain.HistoryUpdateUseCase
@@ -405,9 +407,11 @@ class ReaderViewModel @Inject constructor(
     private fun loadImpl() {
         loadingJob = launchLoadingJob(Dispatchers.Default + EventExceptionHandler(onLoadingError)) {
             var exception: Exception? = null
+            var loadedDetails: MangaDetails? = null
             try {
                 detailsLoadUseCase(intent, force = false)
                     .collect { details ->
+                        loadedDetails = details
                         if (mangaDetails.value == null) {
                             mangaDetails.value = details
                         }
@@ -452,9 +456,28 @@ class ReaderViewModel @Inject constructor(
                 exception = e.mergeWith(exception)
             }
             if (readingState.value == null) {
-				onLoadingError.call(
+                val loadedManga = loadedDetails // for smart cast
-					exception ?: IllegalStateException("Unable to load manga. This should never happen. Please report"),
+                if (loadedManga != null) {
+                    mangaDetails.value = loadedManga.filterChapters(selectedBranch.value)
+                }
+                val loadingError = when {
+                    exception != null -> exception
+                    loadedManga == null || !loadedManga.isLoaded -> null
+                    loadedManga.isRestricted -> EmptyMangaException(
+                        EmptyMangaReason.RESTRICTED,
+                        loadedManga.toManga(),
+                        null,
                     )
+
+                    loadedManga.allChapters.isEmpty() -> EmptyMangaException(
+                        EmptyMangaReason.NO_CHAPTERS,
+                        loadedManga.toManga(),
+                        null,
+                    )
+
+                    else -> null
+                } ?: IllegalStateException("Unable to load manga. This should never happen. Please report")
+                onLoadingError.call(loadingError)
             } else exception?.let { e ->
                 // manga has been loaded but error occurred
                 errorEvent.call(e)