gate the library on playback restore so the bottom bar lands in place

The tab bar was laid out before playback was known, so the restored mini player arrived
later and re-laid the whole bottom area: a couple of frames of bump, and the mini player
"loading in" after the library. SubtracksRoot now waits for PlaybackController to finish
connecting and restoring (a `ready` flag, set after restore or on disconnect) before it
composes the library, so the first library frame already includes the mini player and
nothing moves.

With playback resolved up front, the `restored` flag and its special enter/inset specs
are pointless, so they are reverted; playback the user starts animates as before.

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

@@ -52,7 +52,6 @@ data class PlaybackState(
     val hasPrevious: Boolean = false,
     val shuffle: Boolean = false,
     val repeat: RepeatMode = RepeatMode.Off,
-    val restored: Boolean = false,
 )
 
 private sealed interface QueueUndo {
@@ -128,7 +127,6 @@ class PlaybackController(
     private var repeatMode = RepeatMode.Off
     private var endedHandled = false
     private var lastSavedPositionMs = 0L
-    private var restored = false
 
     init {
         scope.launch {
@@ -152,6 +150,9 @@ class PlaybackController(
         scope.cancel()
     }
 
+    private val _ready = MutableStateFlow(false)
+    val ready: StateFlow<Boolean> = _ready
+
     fun connect() {
         if (player != null || connecting) return
         connecting = true
@@ -170,12 +171,14 @@ class PlaybackController(
                         shuffle != null -> startShuffled(shuffle)
                         else -> restore()
                     }
+                    _ready.value = true
                 }
             },
             onDisconnected = {
                 player = null
                 connecting = false
                 scope.launch { stop() }
+                _ready.value = true
             },
         )
     }
@@ -228,7 +231,6 @@ class PlaybackController(
             windowEnd = -1
             lastEdit = null
             endedHandled = false
-            restored = false
             val previous = snapshot
             val previousEntry = previous?.entries?.firstOrNull()?.entry
             val same = previousEntry != null && previousEntry.kind == entry.kind && previousEntry.refId == entry.refId
@@ -604,7 +606,6 @@ class PlaybackController(
         windowEnd = -1
         lastEdit = null
         endedHandled = false
-        restored = false
         val modes = queueRepository.modes()
         shuffleEnabled = !disableShuffle && modes.shuffle
         repeatMode = modes.repeat.toRepeatMode()
@@ -665,7 +666,6 @@ class PlaybackController(
             this.queueSourceId = queueSourceId
             val position = queueRepository.cursor().coerceIn(0, snapshot.size - 1)
             lastSavedPositionMs = queueRepository.cursorPositionMs().coerceAtLeast(0)
-            restored = true
             loadWindow(position, autoplay = false, startPositionMs = lastSavedPositionMs)
         }
 
@@ -681,7 +681,6 @@ class PlaybackController(
         windowStart = 0
         windowEnd = -1
         lastEdit = null
-        restored = false
         player?.run {
             stop()
             clear()
@@ -943,7 +942,6 @@ class PlaybackController(
                 hasPrevious = true,
                 shuffle = shuffleEnabled,
                 repeat = repeatMode,
-                restored = restored,
             )
         if (player.isPlaying) startPositionTicker() else stopPositionTicker()
     }

app/src/main/kotlin/com/subtracks/ui/AppRoot.kt

@@ -4,11 +4,8 @@ import android.net.Uri
 import androidx.activity.OnBackPressedCallback
 import androidx.activity.compose.LocalOnBackPressedDispatcherOwner
 import androidx.compose.animation.AnimatedVisibility
-import androidx.compose.animation.EnterTransition
-import androidx.compose.animation.ExitTransition
 import androidx.compose.animation.core.animate
 import androidx.compose.animation.core.animateDpAsState
-import androidx.compose.animation.core.snap
 import androidx.compose.animation.core.tween
 import androidx.compose.animation.expandVertically
 import androidx.compose.animation.fadeIn
@@ -143,9 +140,20 @@ internal fun focusPops(
 @Composable
 fun SubtracksRoot(root: RootViewModel = koinViewModel()) {
     when (val hasSource = root.hasSource.collectAsStateWithLifecycle().value) {
-        null -> LoadingState()
-        false -> AddSourceRoute(onSaved = {}, onBack = null)
-        true -> MainNavigation()
+        null -> {
+            LoadingState()
+        }
+
+        false -> {
+            AddSourceRoute(onSaved = {}, onBack = null)
+        }
+
+        true -> {
+            val playbackController = koinInject<PlaybackController>()
+            LaunchedEffect(Unit) { playbackController.connect() }
+            val playbackReady by playbackController.ready.collectAsStateWithLifecycle()
+            if (playbackReady) MainNavigation() else LoadingState()
+        }
     }
 }
 
@@ -219,7 +227,6 @@ private fun MainNavigation() {
             else -> repeat(pops) { navController.popBackStack() }
         }
     }
-    LaunchedEffect(Unit) { playbackController.connect() }
     LaunchedEffect(Unit) { if (nowPlayingOpen) nowPlayingProgress = 1f }
 
     val playerVisible = playback.item != null
@@ -236,7 +243,7 @@ private fun MainNavigation() {
     val showMiniPlayer = playerVisible && !keyboardUp
     val bottomInset by animateDpAsState(
         targetValue = if (showMiniPlayer) 0.dp else navBarInset,
-        animationSpec = if (playback.restored) snap() else tween(MINI_PLAYER_ANIM_MS),
+        animationSpec = tween(MINI_PLAYER_ANIM_MS),
         label = "libraryBottomInset",
     )
 
@@ -379,18 +386,8 @@ private fun MainNavigation() {
 
                 AnimatedVisibility(
                     visible = showMiniPlayer,
-                    enter =
-                        if (playback.restored) {
-                            EnterTransition.None
-                        } else {
-                            expandVertically(tween(MINI_PLAYER_ANIM_MS), expandFrom = Alignment.Bottom)
-                        },
-                    exit =
-                        if (playback.restored) {
-                            ExitTransition.None
-                        } else {
-                            shrinkVertically(tween(MINI_PLAYER_ANIM_MS), shrinkTowards = Alignment.Bottom)
-                        },
+                    enter = expandVertically(tween(MINI_PLAYER_ANIM_MS), expandFrom = Alignment.Bottom),
+                    exit = shrinkVertically(tween(MINI_PLAYER_ANIM_MS), shrinkTowards = Alignment.Bottom),
                 ) {
                     val positionMs by playbackController.positionMs.collectAsStateWithLifecycle()
                     val miniArt = playbackController.coverArt(playback.item, thumbnail = true)

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

@@ -28,6 +28,7 @@ import okhttp3.OkHttpClient
 import org.junit.After
 import org.junit.Assert.assertEquals
 import org.junit.Assert.assertFalse
+import org.junit.Assert.assertNotNull
 import org.junit.Assert.assertTrue
 import org.junit.Before
 import org.junit.Test
@@ -161,17 +162,16 @@ class PlaybackControllerTest {
     }
 
     @Test
-    fun restoringMarksTheStateUntilPlaybackStarts() {
+    fun theReadyStateResolvesWithTheRestoredItemAlreadyInPlace() {
         seedAlbum(5, sourceId = 1)
         runBlocking { queues.replace(listOf(queues.albumEntry(1, "al1"))) }
 
+        assertFalse(controller.ready.value)
+
         controller.connect()
-        await { handle.items.isNotEmpty() }
+        await { controller.ready.value }
 
-        assertTrue(controller.state.value.restored)
-
-        controller.playAlbum(1, "al1", 0)
-        await { !controller.state.value.restored }
+        assertNotNull("the mini player must be drawable once ready", controller.state.value.item)
     }
 
     @Test