android/app/src/main/java/com/fabledsword/minstrel/player/PlayerController.kt

@@ -3,6 +3,8 @@ package com.fabledsword.minstrel.player
 import android.content.ComponentName
 import android.content.Context
 import android.os.Bundle
+import android.os.Handler
+import android.os.Looper
 import androidx.media3.common.MediaItem
 import androidx.media3.common.MediaMetadata
 import androidx.media3.common.Player
@@ -187,9 +189,26 @@ class PlayerController @Inject constructor(
         val controller = mediaController ?: return
         queueRefs = tracks
         val items = tracks.map { it.toMediaItem(source) }
-        controller.setMediaItems(items, initialIndex, /* startPositionMs = */ 0L)
-        controller.prepare()
-        if (autoplay) controller.play()
+        // Drift #562 cold-boot resume calls this from a non-Main suspend
+        // context after awaitReady() unblocks (ResumeController launches
+        // on Dispatchers.Default by the time it reaches us). MediaController
+        // enforces application-thread access and throws
+        // IllegalStateException otherwise — post to its applicationLooper
+        // if we're already there, run directly to avoid the re-dispatch
+        // latency UI callers depend on.
+        runOnControllerThread(controller) {
+            controller.setMediaItems(items, initialIndex, /* startPositionMs = */ 0L)
+            controller.prepare()
+            if (autoplay) controller.play()
+        }
+    }
+
+    private fun runOnControllerThread(controller: MediaController, block: () -> Unit) {
+        if (Looper.myLooper() == controller.applicationLooper) {
+            block()
+        } else {
+            Handler(controller.applicationLooper).post(block)
+        }
     }
 
     /**