keep the playing context and window across an offline toggle

app/src/main/kotlin/com/subtracks/playback/PlaybackController.kt

@@ -146,6 +146,7 @@ class PlaybackController(
     private val offline: Boolean get() = sourceRepository.offline.value
     private var windowPositions = LongArray(0)
     private var windowFiltered = false
+    private var contextOverride: QueueContext? = null
 
     init {
         scope.launch {
@@ -154,7 +155,7 @@ class PlaybackController(
             }
         }
         scope.launch {
-            sourceRepository.offline.drop(1).collect { reloadForOffline() }
+            sourceRepository.offline.collect { reloadForOffline() }
         }
         scope.launch {
             sourceRepository.quality.drop(1).collect {
@@ -243,6 +244,7 @@ class PlaybackController(
         disableShuffle: Boolean = false,
     ) {
         if (!offline) {
+            contextOverride = null
             play(listOf(entry), start, disableShuffle)
             return
         }
@@ -252,12 +254,14 @@ class PlaybackController(
                 showMessage("Nothing downloaded for offline playback")
                 return@launch
             }
+            contextOverride = QueueContext(entry.kind, entry.sourceId, entry.refId)
             play(entries, start, disableShuffle = true)
         }
     }
 
     private fun shuffleContext(entry: QueueEntry) {
         if (!offline) {
+            contextOverride = null
             shufflePlay(listOf(entry))
             return
         }
@@ -267,6 +271,7 @@ class PlaybackController(
                 showMessage("Nothing downloaded for offline playback")
                 return@launch
             }
+            contextOverride = QueueContext(entry.kind, entry.sourceId, entry.refId)
             shufflePlay(entries)
         }
     }
@@ -1019,6 +1024,7 @@ class PlaybackController(
         windowEnd = -1
         windowPositions = LongArray(0)
         windowFiltered = false
+        contextOverride = null
         lastPosition = null
         lastEdit = null
         player?.run {
@@ -1387,6 +1393,7 @@ class PlaybackController(
     }
 
     private fun contextAt(position: Long?): QueueContext? {
+        contextOverride?.let { return it }
         val snapshot = snapshot ?: return null
         val play = position?.let { snapshot.anchorContextPlay(it) } ?: return null
         val entry = snapshot.locateContext(play)?.first ?: return null

app/src/test/kotlin/com/subtracks/playback/PlaybackControllerTest.kt

@@ -73,7 +73,7 @@ class PlaybackControllerTest {
         networkMode = MutableStateFlow(NetworkMode.Wifi)
         sources = SourceRepository(db, OkHttpClient(), prefs, ArtworkStore(File(context.cacheDir, "art")), networkMode = networkMode)
         queues = QueueRepository(db)
-        downloadsDir = File(context.cacheDir, "downloads")
+        downloadsDir = File(context.cacheDir, "downloads-${System.nanoTime()}")
         downloads =
             DownloadRepository(
                 db,
@@ -2495,6 +2495,69 @@ class PlaybackControllerTest {
         )
     }
 
+    @Test
+    fun offlinePlayAlbumKeepsTheAlbumAsThePlayingContext() {
+        seedAlbum(4, sourceId = 1)
+        markDownloaded(1, "s1")
+        markDownloaded(1, "s3")
+        setOffline()
+
+        controller.playAlbum(1, "al1", 0)
+
+        await {
+            controller.state.value.context
+                ?.kind == QueueKind.Album
+        }
+        assertEquals(
+            QueueKind.Album,
+            controller.state.value.context
+                ?.kind,
+        )
+        assertEquals(
+            "al1",
+            controller.state.value.context
+                ?.refId,
+        )
+    }
+
+    @Test
+    fun offlineUpNextPlaysAndIsConsumed() {
+        seedAlbum(8, sourceId = 1)
+        seedSong("x1", "al2")
+        (1..8).filter { it != 2 }.forEach { markDownloaded(1, "s$it") }
+        markDownloaded(1, "x1")
+
+        controller.playAlbum(1, "al1", 3)
+        await {
+            controller.state.value.item
+                ?.id == "s4"
+        }
+
+        setOffline()
+        await { handle.items.map { it.id } == listOf("s1", "s3", "s4", "s5", "s6", "s7", "s8") }
+
+        controller.addToQueue(1, QueueKind.Song, "x1")
+        await { runBlocking { queues.snapshot().upNextSize } == 1L }
+
+        controller.next()
+        await {
+            controller.state.value.item
+                ?.id == "x1"
+        }
+
+        controller.next()
+        await { runBlocking { queues.snapshot().upNextSize } == 0L }
+        await {
+            controller.state.value.item
+                ?.id == "s5"
+        }
+        assertEquals(
+            "s5",
+            controller.state.value.item
+                ?.id,
+        )
+    }
+
     @Test
     fun offlinePlayAlbumBuildsADownloadedOnlyQueue() {
         seedAlbum(4, sourceId = 1)