playback: wrap adjacent artwork with repeat

The now playing strip took its neighbours from previousItem() and upcomingItem(), which returned null at the queue edges online even when repeat would wrap. Swiping there resisted and only a hard fling advanced the track, leaving no artwork to slide in. Mirror next() and previousTrack() so the online path wraps with repeat All, and with repeat One for the next slot.

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

@@ -934,7 +934,17 @@ class PlaybackController(
         }
         val snapshot = current ?: return null
         val at = position ?: return null
-        if (!isOffline) return queueRepository.itemAt(snapshot, at + 1)?.toQueueItem()
+        if (!isOffline) {
+            val next =
+                if (at + 1 < snapshot.size) {
+                    at + 1
+                } else if (repeatMode != RepeatMode.Off) {
+                    0L
+                } else {
+                    null
+                }
+            return next?.let { queueRepository.itemAt(snapshot, it)?.toQueueItem() }
+        }
         downloads.awaitLoaded()
         val target =
             downloadedAtOrAfter(snapshot, at + 1)
@@ -953,7 +963,15 @@ class PlaybackController(
         }
         val snapshot = current ?: return null
         val at = position ?: return null
-        if (!isOffline) return if (at <= 0) null else queueRepository.itemAt(snapshot, at - 1)?.toQueueItem()
+        if (!isOffline) {
+            val previous =
+                when {
+                    at > 0 -> at - 1
+                    repeatMode == RepeatMode.All -> snapshot.size - 1
+                    else -> return null
+                }
+            return queueRepository.itemAt(snapshot, previous)?.toQueueItem()
+        }
         downloads.awaitLoaded()
         val target =
             downloadedAtOrBefore(snapshot, at - 1)

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

@@ -218,6 +218,61 @@ class PlaybackControllerTest {
         assertNull(runBlocking { controller.previousItem() })
     }
 
+    @Test
+    fun previousItemWrapsToTheEndWithRepeatAll() {
+        seedAlbum(3, sourceId = 1)
+        controller.playAlbum(1, "al1", 0)
+        await {
+            controller.state.value.item
+                ?.id == "s1"
+        }
+        controller.cycleRepeat()
+        assertEquals(RepeatMode.All, controller.state.value.repeat)
+
+        assertEquals("s3", runBlocking { controller.previousItem()?.id })
+    }
+
+    @Test
+    fun upcomingItemIsNullAtTheEndOfTheQueue() {
+        seedAlbum(3, sourceId = 1)
+        controller.playAlbum(1, "al1", 2)
+        await {
+            controller.state.value.item
+                ?.id == "s3"
+        }
+
+        assertNull(runBlocking { controller.upcomingItem() })
+    }
+
+    @Test
+    fun upcomingItemWrapsToTheStartWithRepeatAll() {
+        seedAlbum(3, sourceId = 1)
+        controller.playAlbum(1, "al1", 2)
+        await {
+            controller.state.value.item
+                ?.id == "s3"
+        }
+        controller.cycleRepeat()
+        assertEquals(RepeatMode.All, controller.state.value.repeat)
+
+        assertEquals("s1", runBlocking { controller.upcomingItem()?.id })
+    }
+
+    @Test
+    fun upcomingItemWrapsToTheStartWithRepeatOne() {
+        seedAlbum(3, sourceId = 1)
+        controller.playAlbum(1, "al1", 2)
+        await {
+            controller.state.value.item
+                ?.id == "s3"
+        }
+        controller.cycleRepeat()
+        controller.cycleRepeat()
+        assertEquals(RepeatMode.One, controller.state.value.repeat)
+
+        assertEquals("s1", runBlocking { controller.upcomingItem()?.id })
+    }
+
     @Test
     fun previousTrackMovesBackEvenOncePreviousWouldRestart() {
         seedAlbum(3, sourceId = 1)