fix(android): duration falls back to local while Sonos hasn't reported one

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

@@ -433,7 +433,11 @@ class PlayerController @Inject constructor(
                     // no real audio loaded -- player.duration / isPlaying /
                     // currentPosition all reflect that. Read from remoteState
                     // instead so an onEvents fire (e.g. activity resume) doesn't
-                    // clobber the UI with zeros.
+                    // clobber the UI with zeros. Duration falls back to the
+                    // wrapped player's value when Sonos hasn't reported one yet
+                    // (pre-first-poll window, or Sonos still buffering) -- the
+                    // wrapped ExoPlayer was prepared with the same MediaItem so
+                    // it knows the real duration before any SOAP poll lands.
                     val upnpActive = activeUpnpHolder.active.value != null
                     uiStateInternal.value =
                         PlayerUiState(
@@ -448,11 +452,11 @@ class PlayerController @Inject constructor(
                             } else {
                                 player.currentPosition
                             }.coerceAtLeast(0),
-                            durationMs = if (upnpActive) {
-                                remoteState.durationMs
-                            } else {
-                                player.duration
-                            }.coerceAtLeast(0),
+                            durationMs = effectiveDuration(
+                                upnpActive,
+                                remoteState.durationMs,
+                                player.duration,
+                            ),
                             bufferedPositionMs = player.bufferedPosition.coerceAtLeast(0),
                             playbackError = player.playerError?.message,
                             currentSource = source,
@@ -497,11 +501,13 @@ class PlayerController @Inject constructor(
                     if (upnpActive) remoteState.isPlaying else controller.isPlaying
                 val effectivePosition =
                     if (upnpActive) remoteState.positionMs else controller.currentPosition
-                val effectiveDuration =
-                    if (upnpActive) remoteState.durationMs else controller.duration
                 val current = uiStateInternal.value
                 val newPos = effectivePosition.coerceAtLeast(0)
-                val newDur = effectiveDuration.coerceAtLeast(0)
+                val newDur = effectiveDuration(
+                    upnpActive,
+                    remoteState.durationMs,
+                    controller.duration,
+                )
                 val newBuf = controller.bufferedPosition.coerceAtLeast(0)
                 val changed = current.isPlaying != effectiveIsPlaying ||
                     current.positionMs != newPos ||
@@ -574,6 +580,18 @@ class PlayerController @Inject constructor(
     private fun sourceExtras(source: String): Bundle =
         Bundle().apply { putString(MINSTREL_SOURCE_KEY, source) }
 
+    /**
+     * Duration to surface to the UI. When UPnP is active the remote's
+     * reported duration wins -- but if Sonos hasn't reported one yet
+     * (pre-first-poll window after activation, or transient 0 during a
+     * track-change buffer), fall back to the wrapped ExoPlayer's value
+     * for that MediaItem so the scrubber doesn't blink to zero.
+     */
+    private fun effectiveDuration(upnpActive: Boolean, remoteMs: Long, localMs: Long): Long {
+        val pick = if (upnpActive && remoteMs > 0) remoteMs else localMs
+        return pick.coerceAtLeast(0)
+    }
+
     companion object {
         const val MINSTREL_SOURCE_KEY: String = "minstrel_source"
     }