fix: avoid syncing beat metadata twice when returning from Now Playing -> Library

app/src/main/java/at/lockstep/player/LockstepViewModel.kt

@@ -453,6 +453,22 @@ class LockstepViewModel(
         }
     }
 
+    /** Set before popping Now Playing; [consumeSuppressNextLibraryMetadataSync] skips one Library batch sync. */
+    @Volatile
+    private var suppressNextLibraryMetadataSync = false
+
+    fun suppressNextLibraryMetadataSync() {
+        suppressNextLibraryMetadataSync = true
+    }
+
+    fun consumeSuppressNextLibraryMetadataSync(): Boolean {
+        if (!suppressNextLibraryMetadataSync) {
+            return false
+        }
+        suppressNextLibraryMetadataSync = false
+        return true
+    }
+
     suspend fun syncPendingMetadata(): String? {
         val token = spotifyAccessToken.value
         if (token.isNullOrBlank()) {

app/src/main/java/at/lockstep/player/ui/LockstepAppNavHost.kt

@@ -116,7 +116,10 @@ fun LockstepAppNavHost(
                 playlistId = playlistId,
                 playback = playback,
                 viewModel = viewModel,
-                onBack = { navController.popBackStack() },
+                onBack = {
+                    viewModel.suppressNextLibraryMetadataSync()
+                    navController.popBackStack()
+                },
             )
         }
         composable(

app/src/main/java/at/lockstep/player/ui/NowPlayingScreen.kt

@@ -2,6 +2,7 @@ package at.lockstep.player.ui
 
 import android.Manifest
 import android.content.pm.PackageManager
+import androidx.activity.compose.BackHandler
 import androidx.activity.compose.rememberLauncherForActivityResult
 import androidx.activity.result.contract.ActivityResultContracts
 import androidx.compose.foundation.layout.Arrangement
@@ -169,6 +170,7 @@ fun NowPlayingRoute(
     modifier: Modifier = Modifier,
 ) {
     val context = LocalContext.current
+    BackHandler(onBack = onBack)
     val collectRunData by viewModel.collectRunData.collectAsStateWithLifecycle()
     val collector = remember { RunDataCollector(context) }
     val runSessionFolder = remember { RunDataStorage.newRunSessionFolderName() }

app/src/main/java/at/lockstep/player/ui/library/LibraryScreen.kt

@@ -49,10 +49,11 @@ fun LibraryScreen(
 
     LaunchedEffect(token) {
         if (token.isNullOrBlank()) return@LaunchedEffect
+        val skipMetadataSync = viewModel.consumeSuppressNextLibraryMetadataSync()
         val errors =
             listOfNotNull(
                 viewModel.syncJukeboxIfToken(),
-                viewModel.syncPendingMetadata(),
+                if (skipMetadataSync) null else viewModel.syncPendingMetadata(),
             )
         if (errors.isNotEmpty()) {
             Toast.makeText(context, errors.joinToString("\n"), Toast.LENGTH_LONG).show()