Feature/decouple thumbnail downloads and cache (#581)

* Rename "DownloadedFilesProvider" to "ChaptersFilesProvider"

* Move files into sub packages

* Further abstract "DownloadedFilesProvider"

* Rename "getCachedImageResponse" to "getImageResponse"

* Extract getting cached image response into new function

* Decouple thumbnail cache and download

* Download and delete permanent thumbnails

When adding/removing manga from/to the library make sure the permanent thumbnail files will get handled properly

* Move thumbnail cache to actual temp folder

* Rename "mangaDownloadsRoot" to "downloadRoot"

* Move manga downloads into "mangas" subfolder

* Clear downloaded thumbnail

server/src/main/kotlin/suwayomi/tachidesk/graphql/mutations/MangaMutation.kt

@@ -8,6 +8,7 @@ import org.jetbrains.exposed.sql.transactions.transaction
 import org.jetbrains.exposed.sql.update
 import suwayomi.tachidesk.graphql.types.MangaMetaType
 import suwayomi.tachidesk.graphql.types.MangaType
+import suwayomi.tachidesk.manga.impl.Library
 import suwayomi.tachidesk.manga.impl.Manga
 import suwayomi.tachidesk.manga.model.table.MangaMetaTable
 import suwayomi.tachidesk.manga.model.table.MangaTable
@@ -44,7 +45,7 @@ class MangaMutation {
         val patch: UpdateMangaPatch
     )
 
-    private fun updateMangas(ids: List<Int>, patch: UpdateMangaPatch) {
+    private suspend fun updateMangas(ids: List<Int>, patch: UpdateMangaPatch) {
         transaction {
             if (patch.inLibrary != null) {
                 MangaTable.update({ MangaTable.id inList ids }) { update ->
@@ -53,37 +54,47 @@ class MangaMutation {
                     }
                 }
             }
+        }.apply {
+            if (patch.inLibrary != null) {
+                ids.forEach {
+                    Library.handleMangaThumbnail(it, patch.inLibrary)
+                }
+            }
         }
     }
 
-    fun updateManga(input: UpdateMangaInput): UpdateMangaPayload {
+    fun updateManga(input: UpdateMangaInput): CompletableFuture<UpdateMangaPayload> {
         val (clientMutationId, id, patch) = input
 
-        updateMangas(listOf(id), patch)
+        return future {
+            updateMangas(listOf(id), patch)
+        }.thenApply {
+            val manga = transaction {
+                MangaType(MangaTable.select { MangaTable.id eq id }.first())
+            }
 
-        val manga = transaction {
+            UpdateMangaPayload(
-            MangaType(MangaTable.select { MangaTable.id eq id }.first())
+                clientMutationId = clientMutationId,
+                manga = manga
+            )
         }
-
-        return UpdateMangaPayload(
-            clientMutationId = clientMutationId,
-            manga = manga
-        )
     }
 
-    fun updateMangas(input: UpdateMangasInput): UpdateMangasPayload {
+    fun updateMangas(input: UpdateMangasInput): CompletableFuture<UpdateMangasPayload> {
         val (clientMutationId, ids, patch) = input
 
-        updateMangas(ids, patch)
+        return future {
+            updateMangas(ids, patch)
+        }.thenApply {
+            val mangas = transaction {
+                MangaTable.select { MangaTable.id inList ids }.map { MangaType(it) }
+            }
 
-        val mangas = transaction {
+            UpdateMangasPayload(
-            MangaTable.select { MangaTable.id inList ids }.map { MangaType(it) }
+                clientMutationId = clientMutationId,
+                mangas = mangas
+            )
         }
-
-        return UpdateMangasPayload(
-            clientMutationId = clientMutationId,
-            mangas = mangas
-        )
     }
 
     data class FetchMangaInput(

server/src/main/kotlin/suwayomi/tachidesk/manga/impl/ChapterDownloadHelper.kt

@@ -1,9 +1,9 @@
 package suwayomi.tachidesk.manga.impl
 
 import kotlinx.coroutines.CoroutineScope
-import suwayomi.tachidesk.manga.impl.download.ArchiveProvider
+import suwayomi.tachidesk.manga.impl.download.fileProvider.ChaptersFilesProvider
-import suwayomi.tachidesk.manga.impl.download.DownloadedFilesProvider
+import suwayomi.tachidesk.manga.impl.download.fileProvider.impl.ArchiveProvider
-import suwayomi.tachidesk.manga.impl.download.FolderProvider
+import suwayomi.tachidesk.manga.impl.download.fileProvider.impl.FolderProvider
 import suwayomi.tachidesk.manga.impl.download.model.DownloadChapter
 import suwayomi.tachidesk.manga.impl.util.getChapterCbzPath
 import suwayomi.tachidesk.manga.impl.util.getChapterDownloadPath
@@ -13,7 +13,7 @@ import java.io.InputStream
 
 object ChapterDownloadHelper {
     fun getImage(mangaId: Int, chapterId: Int, index: Int): Pair<InputStream, String> {
-        return provider(mangaId, chapterId).getImage(index)
+        return provider(mangaId, chapterId).getImage().execute(index)
     }
 
     fun delete(mangaId: Int, chapterId: Int): Boolean {
@@ -27,11 +27,11 @@ object ChapterDownloadHelper {
         scope: CoroutineScope,
         step: suspend (DownloadChapter?, Boolean) -> Unit
     ): Boolean {
-        return provider(mangaId, chapterId).download(download, scope, step)
+        return provider(mangaId, chapterId).download().execute(download, scope, step)
     }
 
     // return the appropriate provider based on how the download was saved. For the logic is simple but will evolve when new types of downloads are available
-    private fun provider(mangaId: Int, chapterId: Int): DownloadedFilesProvider {
+    private fun provider(mangaId: Int, chapterId: Int): ChaptersFilesProvider {
         val chapterFolder = File(getChapterDownloadPath(mangaId, chapterId))
         val cbzFile = File(getChapterCbzPath(mangaId, chapterId))
         if (cbzFile.exists()) return ArchiveProvider(mangaId, chapterId)

server/src/main/kotlin/suwayomi/tachidesk/manga/impl/Library.kt

@@ -7,6 +7,10 @@ package suwayomi.tachidesk.manga.impl
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
 
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.SupervisorJob
+import kotlinx.coroutines.launch
 import org.jetbrains.exposed.sql.and
 import org.jetbrains.exposed.sql.insert
 import org.jetbrains.exposed.sql.select
@@ -19,6 +23,8 @@ import suwayomi.tachidesk.manga.model.table.MangaTable
 import java.time.Instant
 
 object Library {
+    private val scope = CoroutineScope(SupervisorJob() + Dispatchers.Default)
+
     suspend fun addMangaToLibrary(mangaId: Int) {
         val manga = getManga(mangaId)
         if (!manga.inLibrary) {
@@ -41,6 +47,8 @@ object Library {
                         }
                     }
                 }
+            }.apply {
+                handleMangaThumbnail(mangaId, true)
             }
         }
     }
@@ -52,6 +60,22 @@ object Library {
                 MangaTable.update({ MangaTable.id eq manga.id }) {
                     it[inLibrary] = false
                 }
+            }.apply {
+                handleMangaThumbnail(mangaId, false)
+            }
+        }
+    }
+
+    fun handleMangaThumbnail(mangaId: Int, inLibrary: Boolean) {
+        scope.launch {
+            try {
+                if (inLibrary) {
+                    ThumbnailDownloadHelper.download(mangaId)
+                } else {
+                    ThumbnailDownloadHelper.delete(mangaId)
+                }
+            } catch (e: Exception) {
+                // ignore
             }
         }
     }

server/src/main/kotlin/suwayomi/tachidesk/manga/impl/Manga.kt

@@ -25,12 +25,13 @@ import org.kodein.di.conf.global
 import org.kodein.di.instance
 import suwayomi.tachidesk.manga.impl.MangaList.proxyThumbnailUrl
 import suwayomi.tachidesk.manga.impl.Source.getSource
+import suwayomi.tachidesk.manga.impl.download.fileProvider.impl.MissingThumbnailException
 import suwayomi.tachidesk.manga.impl.util.network.await
 import suwayomi.tachidesk.manga.impl.util.source.GetCatalogueSource.getCatalogueSourceOrNull
 import suwayomi.tachidesk.manga.impl.util.source.GetCatalogueSource.getCatalogueSourceOrStub
 import suwayomi.tachidesk.manga.impl.util.source.StubSource
 import suwayomi.tachidesk.manga.impl.util.storage.ImageResponse.clearCachedImage
-import suwayomi.tachidesk.manga.impl.util.storage.ImageResponse.getCachedImageResponse
+import suwayomi.tachidesk.manga.impl.util.storage.ImageResponse.getImageResponse
 import suwayomi.tachidesk.manga.impl.util.storage.ImageUtil
 import suwayomi.tachidesk.manga.impl.util.updateMangaDownloadDir
 import suwayomi.tachidesk.manga.model.dataclass.MangaDataClass
@@ -126,7 +127,7 @@ object Manga {
                 if (!sManga.thumbnail_url.isNullOrEmpty() && sManga.thumbnail_url != mangaEntry[MangaTable.thumbnail_url]) {
                     it[MangaTable.thumbnail_url] = sManga.thumbnail_url
                     it[MangaTable.thumbnailUrlLastFetched] = Instant.now().epochSecond
-                    clearMangaThumbnailCache(mangaId)
+                    clearThumbnail(mangaId)
                 }
 
                 it[MangaTable.realUrl] = runCatching {
@@ -232,15 +233,16 @@ object Manga {
 
     private val applicationDirs by DI.global.instance<ApplicationDirs>()
     private val network: NetworkHelper by injectLazy()
-    suspend fun getMangaThumbnail(mangaId: Int): Pair<InputStream, String> {
+
-        val cacheSaveDir = applicationDirs.thumbnailsRoot
+    suspend fun fetchMangaThumbnail(mangaId: Int): Pair<InputStream, String> {
+        val cacheSaveDir = applicationDirs.tempThumbnailCacheRoot
         val fileName = mangaId.toString()
 
         val mangaEntry = transaction { MangaTable.select { MangaTable.id eq mangaId }.first() }
         val sourceId = mangaEntry[MangaTable.sourceReference]
 
         return when (val source = getCatalogueSourceOrStub(sourceId)) {
-            is HttpSource -> getCachedImageResponse(cacheSaveDir, fileName) {
+            is HttpSource -> getImageResponse(cacheSaveDir, fileName) {
                 val thumbnailUrl = mangaEntry[MangaTable.thumbnail_url]
                     ?: if (!mangaEntry[MangaTable.initialized]) {
                         // initialize then try again
@@ -272,7 +274,7 @@ object Manga {
                 imageFile.inputStream() to contentType
             }
 
-            is StubSource -> getCachedImageResponse(cacheSaveDir, fileName) {
+            is StubSource -> getImageResponse(cacheSaveDir, fileName) {
                 val thumbnailUrl = mangaEntry[MangaTable.thumbnail_url]
                     ?: throw NullPointerException("No thumbnail found")
                 network.client.newCall(
@@ -284,10 +286,25 @@ object Manga {
         }
     }
 
-    private fun clearMangaThumbnailCache(mangaId: Int) {
+    suspend fun getMangaThumbnail(mangaId: Int): Pair<InputStream, String> {
-        val saveDir = applicationDirs.thumbnailsRoot
+        val mangaEntry = transaction { MangaTable.select { MangaTable.id eq mangaId }.first() }
+
+        if (mangaEntry[MangaTable.inLibrary]) {
+            return try {
+                ThumbnailDownloadHelper.getImage(mangaId)
+            } catch (_: MissingThumbnailException) {
+                ThumbnailDownloadHelper.download(mangaId)
+                ThumbnailDownloadHelper.getImage(mangaId)
+            }
+        }
+
+        return fetchMangaThumbnail(mangaId)
+    }
+
+    private fun clearThumbnail(mangaId: Int) {
         val fileName = mangaId.toString()
 
-        clearCachedImage(saveDir, fileName)
+        clearCachedImage(applicationDirs.tempThumbnailCacheRoot, fileName)
+        clearCachedImage(applicationDirs.thumbnailDownloadsRoot, fileName)
     }
 }

server/src/main/kotlin/suwayomi/tachidesk/manga/impl/Page.kt

@@ -19,7 +19,7 @@ import org.jetbrains.exposed.sql.update
 import suwayomi.tachidesk.manga.impl.util.getChapterCachePath
 import suwayomi.tachidesk.manga.impl.util.lang.awaitSingle
 import suwayomi.tachidesk.manga.impl.util.source.GetCatalogueSource.getCatalogueSourceOrStub
-import suwayomi.tachidesk.manga.impl.util.storage.ImageResponse.getCachedImageResponse
+import suwayomi.tachidesk.manga.impl.util.storage.ImageResponse.getImageResponse
 import suwayomi.tachidesk.manga.impl.util.storage.ImageUtil
 import suwayomi.tachidesk.manga.model.table.ChapterTable
 import suwayomi.tachidesk.manga.model.table.MangaTable
@@ -99,7 +99,7 @@ object Page {
         val cacheSaveDir = getChapterCachePath(mangaId, chapterId)
 
         // Note: don't care about invalidating cache because OS cache is not permanent
-        return getCachedImageResponse(cacheSaveDir, fileName) {
+        return getImageResponse(cacheSaveDir, fileName) {
             source.fetchImage(tachiyomiPage).awaitSingle()
         }
     }

server/src/main/kotlin/suwayomi/tachidesk/manga/impl/ThumbnailDownloadHelper.kt

@@ -0,0 +1,23 @@
+package suwayomi.tachidesk.manga.impl
+
+import suwayomi.tachidesk.manga.impl.download.fileProvider.impl.ThumbnailFileProvider
+import java.io.InputStream
+
+object ThumbnailDownloadHelper {
+    fun getImage(mangaId: Int): Pair<InputStream, String> {
+        return provider(mangaId).getImage().execute()
+    }
+
+    fun delete(mangaId: Int): Boolean {
+        return provider(mangaId).delete()
+    }
+
+    suspend fun download(mangaId: Int): Boolean {
+        return provider(mangaId).download().execute()
+    }
+
+    // return the appropriate provider based on how the download was saved. For the logic is simple but will evolve when new types of downloads are available
+    private fun provider(mangaId: Int): ThumbnailFileProvider {
+        return ThumbnailFileProvider(mangaId)
+    }
+}

server/src/main/kotlin/suwayomi/tachidesk/manga/impl/download/DownloadedFilesProvider.kt

@@ -1,20 +0,0 @@
-package suwayomi.tachidesk.manga.impl.download
-
-import kotlinx.coroutines.CoroutineScope
-import suwayomi.tachidesk.manga.impl.download.model.DownloadChapter
-import java.io.InputStream
-
-/*
-* Base class for downloaded chapter files provider, example: Folder, Archive
-* */
-abstract class DownloadedFilesProvider(val mangaId: Int, val chapterId: Int) {
-    abstract fun getImage(index: Int): Pair<InputStream, String>
-
-    abstract suspend fun download(
-        download: DownloadChapter,
-        scope: CoroutineScope,
-        step: suspend (DownloadChapter?, Boolean) -> Unit
-    ): Boolean
-
-    abstract fun delete(): Boolean
-}

server/src/main/kotlin/suwayomi/tachidesk/manga/impl/download/fileProvider/ChaptersFilesProvider.kt

@@ -0,0 +1,40 @@
+package suwayomi.tachidesk.manga.impl.download.fileProvider
+
+import kotlinx.coroutines.CoroutineScope
+import suwayomi.tachidesk.manga.impl.download.model.DownloadChapter
+import java.io.InputStream
+
+/*
+* Base class for downloaded chapter files provider, example: Folder, Archive
+* */
+abstract class ChaptersFilesProvider(val mangaId: Int, val chapterId: Int) : DownloadedFilesProvider {
+    abstract fun getImageImpl(index: Int): Pair<InputStream, String>
+
+    override fun getImage(): RetrieveFile1Args<Int> {
+        return object : RetrieveFile1Args<Int> {
+            override fun execute(a: Int): Pair<InputStream, String> {
+                return getImageImpl(a)
+            }
+        }
+    }
+
+    abstract suspend fun downloadImpl(
+        download: DownloadChapter,
+        scope: CoroutineScope,
+        step: suspend (DownloadChapter?, Boolean) -> Unit
+    ): Boolean
+
+    override fun download(): FileDownload3Args<DownloadChapter, CoroutineScope, suspend (DownloadChapter?, Boolean) -> Unit> {
+        return object : FileDownload3Args<DownloadChapter, CoroutineScope, suspend (DownloadChapter?, Boolean) -> Unit> {
+            override suspend fun execute(
+                a: DownloadChapter,
+                b: CoroutineScope,
+                c: suspend (DownloadChapter?, Boolean) -> Unit
+            ): Boolean {
+                return downloadImpl(a, b, c)
+            }
+        }
+    }
+
+    abstract override fun delete(): Boolean
+}

server/src/main/kotlin/suwayomi/tachidesk/manga/impl/download/fileProvider/DownloadedFilesProvider.kt

@@ -0,0 +1,5 @@
+package suwayomi.tachidesk.manga.impl.download.fileProvider
+
+interface DownloadedFilesProvider : FileDownloader, FileRetriever {
+    fun delete(): Boolean
+}

server/src/main/kotlin/suwayomi/tachidesk/manga/impl/download/fileProvider/FileDownloader.kt

@@ -0,0 +1,29 @@
+package suwayomi.tachidesk.manga.impl.download.fileProvider
+
+@FunctionalInterface
+interface FileDownload {
+    suspend fun executeDownload(vararg args: Any): Boolean
+}
+
+@FunctionalInterface
+interface FileDownload0Args : FileDownload {
+    suspend fun execute(): Boolean
+
+    override suspend fun executeDownload(vararg args: Any): Boolean {
+        return execute()
+    }
+}
+
+@FunctionalInterface
+interface FileDownload3Args<A, B, C> : FileDownload {
+    suspend fun execute(a: A, b: B, c: C): Boolean
+
+    override suspend fun executeDownload(vararg args: Any): Boolean {
+        return execute(args[0] as A, args[1] as B, args[2] as C)
+    }
+}
+
+@FunctionalInterface
+interface FileDownloader {
+    fun download(): FileDownload
+}

server/src/main/kotlin/suwayomi/tachidesk/manga/impl/download/fileProvider/FileRetriever.kt

@@ -0,0 +1,31 @@
+package suwayomi.tachidesk.manga.impl.download.fileProvider
+
+import java.io.InputStream
+
+@FunctionalInterface
+interface RetrieveFile {
+    fun executeGetImage(vararg args: Any): Pair<InputStream, String>
+}
+
+@FunctionalInterface
+interface RetrieveFile0Args : RetrieveFile {
+    fun execute(): Pair<InputStream, String>
+
+    override fun executeGetImage(vararg args: Any): Pair<InputStream, String> {
+        return execute()
+    }
+}
+
+@FunctionalInterface
+interface RetrieveFile1Args<A> : RetrieveFile {
+    fun execute(a: A): Pair<InputStream, String>
+
+    override fun executeGetImage(vararg args: Any): Pair<InputStream, String> {
+        return execute(args[0] as A)
+    }
+}
+
+@FunctionalInterface
+interface FileRetriever {
+    fun getImage(): RetrieveFile
+}

server/src/main/kotlin/suwayomi/tachidesk/manga/impl/download/fileProvider/impl/ArchiveProvider.kt

@@ -1,4 +1,4 @@
-package suwayomi.tachidesk.manga.impl.download
+package suwayomi.tachidesk.manga.impl.download.fileProvider.impl
 
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.Dispatchers
@@ -7,14 +7,15 @@ import org.apache.commons.compress.archivers.zip.ZipArchiveEntry
 import org.apache.commons.compress.archivers.zip.ZipArchiveInputStream
 import org.apache.commons.compress.archivers.zip.ZipArchiveOutputStream
 import org.apache.commons.compress.archivers.zip.ZipFile
+import suwayomi.tachidesk.manga.impl.download.fileProvider.ChaptersFilesProvider
 import suwayomi.tachidesk.manga.impl.download.model.DownloadChapter
 import suwayomi.tachidesk.manga.impl.util.getChapterCbzPath
 import suwayomi.tachidesk.manga.impl.util.getChapterDownloadPath
 import java.io.File
 import java.io.InputStream
 
-class ArchiveProvider(mangaId: Int, chapterId: Int) : DownloadedFilesProvider(mangaId, chapterId) {
+class ArchiveProvider(mangaId: Int, chapterId: Int) : ChaptersFilesProvider(mangaId, chapterId) {
-    override fun getImage(index: Int): Pair<InputStream, String> {
+    override fun getImageImpl(index: Int): Pair<InputStream, String> {
         val cbzPath = getChapterCbzPath(mangaId, chapterId)
         val zipFile = ZipFile(cbzPath)
         val zipEntry = zipFile.entries.toList().sortedWith(compareBy({ it.name }, { it.name }))[index]
@@ -23,7 +24,7 @@ class ArchiveProvider(mangaId: Int, chapterId: Int) : DownloadedFilesProvider(ma
         return Pair(inputStream.buffered(), "image/$fileType")
     }
 
-    override suspend fun download(
+    override suspend fun downloadImpl(
         download: DownloadChapter,
         scope: CoroutineScope,
         step: suspend (DownloadChapter?, Boolean) -> Unit
@@ -33,7 +34,7 @@ class ArchiveProvider(mangaId: Int, chapterId: Int) : DownloadedFilesProvider(ma
         val chapterFolder = File(chapterDir)
         if (outputFile.exists()) handleExistingCbzFile(outputFile, chapterFolder)
 
-        FolderProvider(mangaId, chapterId).download(download, scope, step)
+        FolderProvider(mangaId, chapterId).download().execute(download, scope, step)
 
         withContext(Dispatchers.IO) {
             outputFile.createNewFile()

server/src/main/kotlin/suwayomi/tachidesk/manga/impl/download/fileProvider/impl/FolderProvider.kt

@@ -1,4 +1,4 @@
-package suwayomi.tachidesk.manga.impl.download
+package suwayomi.tachidesk.manga.impl.download.fileProvider.impl
 
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.FlowPreview
@@ -9,6 +9,7 @@ import kotlinx.coroutines.flow.onEach
 import kotlinx.coroutines.flow.sample
 import suwayomi.tachidesk.manga.impl.Page
 import suwayomi.tachidesk.manga.impl.Page.getPageName
+import suwayomi.tachidesk.manga.impl.download.fileProvider.ChaptersFilesProvider
 import suwayomi.tachidesk.manga.impl.download.model.DownloadChapter
 import suwayomi.tachidesk.manga.impl.util.getChapterDownloadPath
 import suwayomi.tachidesk.manga.impl.util.storage.ImageResponse
@@ -19,8 +20,8 @@ import java.io.InputStream
 /*
 * Provides downloaded files when pages were downloaded into folders
 * */
-class FolderProvider(mangaId: Int, chapterId: Int) : DownloadedFilesProvider(mangaId, chapterId) {
+class FolderProvider(mangaId: Int, chapterId: Int) : ChaptersFilesProvider(mangaId, chapterId) {
-    override fun getImage(index: Int): Pair<InputStream, String> {
+    override fun getImageImpl(index: Int): Pair<InputStream, String> {
         val chapterDir = getChapterDownloadPath(mangaId, chapterId)
         val folder = File(chapterDir)
         folder.mkdirs()
@@ -30,7 +31,7 @@ class FolderProvider(mangaId: Int, chapterId: Int) : DownloadedFilesProvider(man
     }
 
     @OptIn(FlowPreview::class)
-    override suspend fun download(
+    override suspend fun downloadImpl(
         download: DownloadChapter,
         scope: CoroutineScope,
         step: suspend (DownloadChapter?, Boolean) -> Unit

server/src/main/kotlin/suwayomi/tachidesk/manga/impl/download/fileProvider/impl/ThumbnailFileProvider.kt

@@ -0,0 +1,87 @@
+package suwayomi.tachidesk.manga.impl.download.fileProvider.impl
+
+import org.kodein.di.DI
+import org.kodein.di.conf.global
+import org.kodein.di.instance
+import suwayomi.tachidesk.manga.impl.Manga
+import suwayomi.tachidesk.manga.impl.download.fileProvider.DownloadedFilesProvider
+import suwayomi.tachidesk.manga.impl.download.fileProvider.FileDownload0Args
+import suwayomi.tachidesk.manga.impl.download.fileProvider.RetrieveFile0Args
+import suwayomi.tachidesk.manga.impl.util.getThumbnailDownloadPath
+import suwayomi.tachidesk.manga.impl.util.storage.ImageResponse
+import suwayomi.tachidesk.manga.impl.util.storage.ImageResponse.getCachedImageResponse
+import suwayomi.tachidesk.server.ApplicationDirs
+import java.io.File
+import java.io.InputStream
+
+class MissingThumbnailException : Exception("No thumbnail found")
+
+private val applicationDirs by DI.global.instance<ApplicationDirs>()
+
+class ThumbnailFileProvider(val mangaId: Int) : DownloadedFilesProvider {
+    private fun getFilePath(): String? {
+        val thumbnailDir = applicationDirs.thumbnailDownloadsRoot
+        val fileName = mangaId.toString()
+        return ImageResponse.findFileNameStartingWith(thumbnailDir, fileName)
+    }
+
+    fun getImageImpl(): Pair<InputStream, String> {
+        val filePathWithoutExt = getThumbnailDownloadPath(mangaId)
+        val filePath = getFilePath()
+
+        if (filePath.isNullOrEmpty()) {
+            throw MissingThumbnailException()
+        }
+
+        return getCachedImageResponse(filePath, filePathWithoutExt)
+    }
+
+    override fun getImage(): RetrieveFile0Args {
+        return object : RetrieveFile0Args {
+            override fun execute(): Pair<InputStream, String> {
+                return getImageImpl()
+            }
+        }
+    }
+
+    suspend fun downloadImpl(): Boolean {
+        val isExistingFile = getFilePath() != null
+        if (isExistingFile) {
+            return true
+        }
+
+        Manga.fetchMangaThumbnail(mangaId).first.use { image ->
+            makeSureDownloadDirExists()
+            val filePath = getThumbnailDownloadPath(mangaId)
+            ImageResponse.saveImage(filePath, image)
+        }
+
+        return true
+    }
+
+    override fun download(): FileDownload0Args {
+        return object : FileDownload0Args {
+            override suspend fun execute(): Boolean {
+                return downloadImpl()
+            }
+        }
+    }
+
+    override fun delete(): Boolean {
+        val filePath = getFilePath()
+        if (filePath.isNullOrEmpty()) {
+            return true
+        }
+
+        return File(filePath).delete()
+    }
+
+    private fun makeSureDownloadDirExists() {
+        val downloadDirPath = applicationDirs.thumbnailDownloadsRoot
+        val downloadDir = File(downloadDirPath)
+
+        if (!downloadDir.exists()) {
+            downloadDir.mkdir()
+        }
+    }
+}

server/src/main/kotlin/suwayomi/tachidesk/manga/impl/extension/Extension.kt

@@ -40,7 +40,7 @@ import suwayomi.tachidesk.manga.impl.util.PackageTools.getPackageInfo
 import suwayomi.tachidesk.manga.impl.util.PackageTools.loadExtensionSources
 import suwayomi.tachidesk.manga.impl.util.network.await
 import suwayomi.tachidesk.manga.impl.util.source.GetCatalogueSource
-import suwayomi.tachidesk.manga.impl.util.storage.ImageResponse.getCachedImageResponse
+import suwayomi.tachidesk.manga.impl.util.storage.ImageResponse.getImageResponse
 import suwayomi.tachidesk.manga.model.table.ExtensionTable
 import suwayomi.tachidesk.manga.model.table.SourceTable
 import suwayomi.tachidesk.server.ApplicationDirs
@@ -329,7 +329,7 @@ object Extension {
 
         val cacheSaveDir = "${applicationDirs.extensionsRoot}/icon"
 
-        return getCachedImageResponse(cacheSaveDir, apkName) {
+        return getImageResponse(cacheSaveDir, apkName) {
             network.client.newCall(
                 GET(iconUrl)
             ).await()

server/src/main/kotlin/suwayomi/tachidesk/manga/impl/util/DirName.kt

@@ -44,6 +44,10 @@ private fun getChapterDir(mangaId: Int, chapterId: Int): String {
     return getMangaDir(mangaId) + "/$chapterDir"
 }
 
+fun getThumbnailDownloadPath(mangaId: Int): String {
+    return applicationDirs.thumbnailDownloadsRoot + "/$mangaId"
+}
+
 fun getChapterDownloadPath(mangaId: Int, chapterId: Int): String {
     return applicationDirs.mangaDownloadsRoot + "/" + getChapterDir(mangaId, chapterId)
 }
@@ -66,8 +70,8 @@ fun updateMangaDownloadDir(mangaId: Int, newTitle: String): Boolean {
 
     val newMangaDir = SafePath.buildValidFilename(newTitle)
 
-    val oldDir = "${applicationDirs.mangaDownloadsRoot}/$sourceDir/$mangaDir"
+    val oldDir = "${applicationDirs.downloadsRoot}/$sourceDir/$mangaDir"
-    val newDir = "${applicationDirs.mangaDownloadsRoot}/$sourceDir/$newMangaDir"
+    val newDir = "${applicationDirs.downloadsRoot}/$sourceDir/$newMangaDir"
 
     val oldDirFile = File(oldDir)
     val newDirFile = File(newDir)

server/src/main/kotlin/suwayomi/tachidesk/manga/impl/util/storage/ImageResponse.kt

@@ -30,6 +30,14 @@ object ImageResponse {
         return null
     }
 
+    fun getCachedImageResponse(cachedFile: String, filePath: String): Pair<InputStream, String> {
+        val fileType = cachedFile.substringAfter("$filePath.")
+        return Pair(
+            pathToInputStream(cachedFile),
+            "image/$fileType"
+        )
+    }
+
     /**
      * Get a cached image response
      *
@@ -38,7 +46,7 @@ object ImageResponse {
      * @param cacheSavePath where to save the cached image. Caller should decide to use perma cache or temp cache (OS temp dir)
      * @param fileName what the saved cache file should be named
      */
-    suspend fun getCachedImageResponse(
+    suspend fun getImageResponse(
         saveDir: String,
         fileName: String,
         fetcher: suspend () -> Response
@@ -50,11 +58,7 @@ object ImageResponse {
 
         // in case the cached file is a ".tmp" file something went wrong with the previous download, and it has to be downloaded again
         if (cachedFile != null && !cachedFile.endsWith(".tmp")) {
-            val fileType = cachedFile.substringAfter("$filePath.")
+            return getCachedImageResponse(cachedFile, filePath)
-            return Pair(
-                pathToInputStream(cachedFile),
-                "image/$fileType"
-            )
         }
 
         val response = fetcher()

server/src/main/kotlin/suwayomi/tachidesk/server/ServerSetup.kt

@@ -45,13 +45,16 @@ class ApplicationDirs(
 ) {
     val cacheRoot = System.getProperty("java.io.tmpdir") + "/tachidesk"
     val extensionsRoot = "$dataRoot/extensions"
-    val thumbnailsRoot = "$dataRoot/thumbnails"
+    val downloadsRoot = serverConfig.downloadsPath.ifBlank { "$dataRoot/downloads" }
-    val mangaDownloadsRoot = serverConfig.downloadsPath.ifBlank { "$dataRoot/downloads" }
     val localMangaRoot = serverConfig.localSourcePath.ifBlank { "$dataRoot/local" }
     val webUIRoot = "$dataRoot/webUI"
     val automatedBackupRoot = serverConfig.backupPath.ifBlank { "$dataRoot/backups" }
 
+    val tempThumbnailCacheRoot = "$tempRoot/thumbnails"
     val tempMangaCacheRoot = "$tempRoot/manga-cache"
+
+    val thumbnailDownloadsRoot = "$downloadsRoot/thumbnails"
+    val mangaDownloadsRoot = "$downloadsRoot/mangas"
 }
 
 val serverConfig: ServerConfig by lazy { GlobalConfigManager.module() }
@@ -96,7 +99,7 @@ fun applicationSetup() {
     logger.debug("Data Root directory is set to: ${applicationDirs.dataRoot}")
 
     // Migrate Directories from old versions
-    File("$ApplicationRootDir/manga-thumbnails").renameTo(applicationDirs.thumbnailsRoot)
+    File("$ApplicationRootDir/manga-thumbnails").renameTo(applicationDirs.tempThumbnailCacheRoot)
     File("$ApplicationRootDir/manga-local").renameTo(applicationDirs.localMangaRoot)
     File("$ApplicationRootDir/anime-thumbnails").delete()
 
@@ -105,8 +108,8 @@ fun applicationSetup() {
         applicationDirs.dataRoot,
         applicationDirs.extensionsRoot,
         applicationDirs.extensionsRoot + "/icon",
-        applicationDirs.thumbnailsRoot,
+        applicationDirs.tempThumbnailCacheRoot,
-        applicationDirs.mangaDownloadsRoot,
+        applicationDirs.downloadsRoot,
         applicationDirs.localMangaRoot
     ).forEach {
         File(it).mkdirs()

server/src/test/kotlin/suwayomi/tachidesk/test/ApplicationTest.kt

@@ -74,8 +74,8 @@ open class ApplicationTest {
                 applicationDirs.dataRoot,
                 applicationDirs.extensionsRoot,
                 applicationDirs.extensionsRoot + "/icon",
-                applicationDirs.thumbnailsRoot,
+                applicationDirs.tempThumbnailCacheRoot,
-                applicationDirs.mangaDownloadsRoot,
+                applicationDirs.downloadsRoot,
                 applicationDirs.localMangaRoot
             ).forEach {
                 File(it).mkdirs()