Fix downloading slowdown

app/src/main/kotlin/org/koitharu/kotatsu/download/ui/worker/DownloadSlowdownDispatcher.kt

@@ -1,16 +1,20 @@
 package org.koitharu.kotatsu.download.ui.worker
 
+import android.os.SystemClock
 import androidx.collection.MutableObjectLongMap
 import kotlinx.coroutines.delay
 import org.koitharu.kotatsu.core.parser.MangaRepository
 import org.koitharu.kotatsu.core.parser.ParserMangaRepository
 import org.koitharu.kotatsu.parsers.model.MangaSource
+import javax.inject.Inject
+import javax.inject.Singleton
 
-class DownloadSlowdownDispatcher(
+@Singleton
+class DownloadSlowdownDispatcher @Inject constructor(
 	private val mangaRepositoryFactory: MangaRepository.Factory,
-	private val defaultDelay: Long,
 ) {
 	private val timeMap = MutableObjectLongMap<MangaSource>()
+	private val defaultDelay = 1_600L
 
 	suspend fun delay(source: MangaSource) {
 		val repo = mangaRepositoryFactory.create(source) as? ParserMangaRepository ?: return
@@ -19,11 +23,11 @@ class DownloadSlowdownDispatcher(
 		}
 		val lastRequest = synchronized(timeMap) {
 			val res = timeMap.getOrDefault(source, 0L)
-			timeMap[source] = System.currentTimeMillis()
+			timeMap[source] = SystemClock.elapsedRealtime()
 			res
 		}
 		if (lastRequest != 0L) {
-			delay(lastRequest + defaultDelay - System.currentTimeMillis())
+			delay(lastRequest + defaultDelay - SystemClock.elapsedRealtime())
 		}
 	}
 }

app/src/main/kotlin/org/koitharu/kotatsu/download/ui/worker/DownloadWorker.kt

@@ -101,6 +101,7 @@ class DownloadWorker @AssistedInject constructor(
 	private val mangaRepositoryFactory: MangaRepository.Factory,
 	private val settings: AppSettings,
 	@LocalStorageChanges private val localStorageChanges: MutableSharedFlow<LocalManga?>,
+	private val slowdownDispatcher: DownloadSlowdownDispatcher,
 	private val imageProxyInterceptor: ImageProxyInterceptor,
 	notificationFactoryFactory: DownloadNotificationFactory.Factory,
 ) : CoroutineWorker(appContext, params) {
@@ -110,7 +111,6 @@ class DownloadWorker @AssistedInject constructor(
 		isSilent = params.inputData.getBoolean(IS_SILENT, false),
 	)
 	private val notificationManager = appContext.getSystemService(Context.NOTIFICATION_SERVICE) as NotificationManager
-	private val slowdownDispatcher = DownloadSlowdownDispatcher(mangaRepositoryFactory, SLOWDOWN_DELAY)
 
 	@Volatile
 	private var lastPublishedState: DownloadState? = null
@@ -569,7 +569,6 @@ class DownloadWorker @AssistedInject constructor(
 		const val MAX_PAGES_PARALLELISM = 4
 		const val DOWNLOAD_ERROR_DELAY = 2_000L
 		const val MAX_RETRY_DELAY = 7_200_000L // 2 hours
-		const val SLOWDOWN_DELAY = 200L
 		const val MANGA_ID = "manga_id"
 		const val CHAPTERS_IDS = "chapters"
 		const val IS_SILENT = "silent"

app/src/main/kotlin/org/koitharu/kotatsu/reader/domain/PageLoader.kt

@@ -1,10 +1,8 @@
 package org.koitharu.kotatsu.reader.domain
 
-import android.content.ContentResolver.MimeTypeInfo
 import android.content.Context
 import android.graphics.Rect
 import android.net.Uri
-import android.webkit.MimeTypeMap
 import androidx.annotation.AnyThread
 import androidx.collection.LongSparseArray
 import androidx.collection.set
@@ -29,6 +27,7 @@ import kotlinx.coroutines.sync.withPermit
 import okhttp3.OkHttpClient
 import okhttp3.Request
 import okio.use
+import org.koitharu.kotatsu.core.image.BitmapDecoderCompat
 import org.koitharu.kotatsu.core.network.CommonHeaders
 import org.koitharu.kotatsu.core.network.MangaHttpClient
 import org.koitharu.kotatsu.core.network.imageproxy.ImageProxyInterceptor
@@ -46,11 +45,13 @@ import org.koitharu.kotatsu.core.util.ext.exists
 import org.koitharu.kotatsu.core.util.ext.getCompletionResultOrNull
 import org.koitharu.kotatsu.core.util.ext.isPowerSaveMode
 import org.koitharu.kotatsu.core.util.ext.isTargetNotEmpty
+import org.koitharu.kotatsu.core.util.ext.mimeType
 import org.koitharu.kotatsu.core.util.ext.printStackTraceDebug
 import org.koitharu.kotatsu.core.util.ext.ramAvailable
 import org.koitharu.kotatsu.core.util.ext.use
 import org.koitharu.kotatsu.core.util.ext.withProgress
 import org.koitharu.kotatsu.core.util.progress.ProgressDeferred
+import org.koitharu.kotatsu.download.ui.worker.DownloadSlowdownDispatcher
 import org.koitharu.kotatsu.local.data.PagesCache
 import org.koitharu.kotatsu.local.data.isFileUri
 import org.koitharu.kotatsu.local.data.isZipUri
@@ -59,8 +60,6 @@ import org.koitharu.kotatsu.parsers.model.MangaSource
 import org.koitharu.kotatsu.parsers.util.mimeType
 import org.koitharu.kotatsu.parsers.util.requireBody
 import org.koitharu.kotatsu.parsers.util.runCatchingCancellable
-import org.koitharu.kotatsu.core.image.BitmapDecoderCompat
-import org.koitharu.kotatsu.core.util.ext.mimeType
 import org.koitharu.kotatsu.reader.ui.pager.ReaderPage
 import java.util.LinkedList
 import java.util.concurrent.atomic.AtomicInteger
@@ -79,6 +78,7 @@ class PageLoader @Inject constructor(
 	private val settings: AppSettings,
 	private val mangaRepositoryFactory: MangaRepository.Factory,
 	private val imageProxyInterceptor: ImageProxyInterceptor,
+	private val downloadSlowdownDispatcher: DownloadSlowdownDispatcher,
 ) {
 
 	val loaderScope = RetainedLifecycleCoroutineScope(lifecycle) + InternalErrorHandler() + Dispatchers.Default
@@ -127,7 +127,7 @@ class PageLoader @Inject constructor(
 		} else if (task?.isCancelled == false) {
 			return task
 		}
-		task = loadPageAsyncImpl(page, force)
+		task = loadPageAsyncImpl(page, skipCache = force, isPrefetch = false)
 		synchronized(tasks) {
 			tasks[page.id] = task
 		}
@@ -186,7 +186,7 @@ class PageLoader @Inject constructor(
 				val page = prefetchQueue.pollFirst() ?: return@launch
 				if (cache.get(page.url) == null) {
 					synchronized(tasks) {
-						tasks[page.id] = loadPageAsyncImpl(page, false)
+						tasks[page.id] = loadPageAsyncImpl(page, skipCache = false, isPrefetch = true)
 					}
 					return@launch
 				}
@@ -194,7 +194,11 @@ class PageLoader @Inject constructor(
 		}
 	}
 
-	private fun loadPageAsyncImpl(page: MangaPage, skipCache: Boolean): ProgressDeferred<Uri, Float> {
+	private fun loadPageAsyncImpl(
+		page: MangaPage,
+		skipCache: Boolean,
+		isPrefetch: Boolean,
+	): ProgressDeferred<Uri, Float> {
 		val progress = MutableStateFlow(PROGRESS_UNDEFINED)
 		val deferred = loaderScope.async {
 			if (!skipCache) {
@@ -202,7 +206,7 @@ class PageLoader @Inject constructor(
 			}
 			counter.incrementAndGet()
 			try {
-				loadPageImpl(page, progress)
+				loadPageImpl(page, progress, isPrefetch)
 			} finally {
 				if (counter.decrementAndGet() == 0) {
 					onIdle()
@@ -222,7 +226,11 @@ class PageLoader @Inject constructor(
 		}
 	}
 
-	private suspend fun loadPageImpl(page: MangaPage, progress: MutableStateFlow<Float>): Uri = semaphore.withPermit {
+	private suspend fun loadPageImpl(
+		page: MangaPage,
+		progress: MutableStateFlow<Float>,
+		isPrefetch: Boolean,
+	): Uri = semaphore.withPermit {
 		val pageUrl = getPageUrl(page)
 		check(pageUrl.isNotBlank()) { "Cannot obtain full image url for $page" }
 		val uri = Uri.parse(pageUrl)
@@ -235,6 +243,9 @@ class PageLoader @Inject constructor(
 
 			uri.isFileUri() -> uri
 			else -> {
+				if (isPrefetch) {
+					downloadSlowdownDispatcher.delay(page.source)
+				}
 				val request = createPageRequest(pageUrl, page.source)
 				imageProxyInterceptor.interceptPageRequest(request, okHttp).ensureSuccess().use { response ->
 					response.requireBody().withProgress(progress).use {