fix(android): Sonos UDN comparison strips _MR/_MS suffix -- coordinator routing

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

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

@@ -13,6 +13,7 @@ import com.fabledsword.minstrel.player.StreamTokenProvider
 import com.fabledsword.minstrel.player.output.upnp.RenderingControlClient
 import com.fabledsword.minstrel.player.output.upnp.SoapClient
 import com.fabledsword.minstrel.player.output.upnp.UpnpDiscoveryController
+import com.fabledsword.minstrel.player.output.upnp.bareUdn
 import dagger.hilt.android.qualifiers.ApplicationContext
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.flow.MutableStateFlow
@@ -100,7 +101,7 @@ class OutputPickerController @Inject constructor(
     ) { sys, upnp, _, upnpSelected ->
         val suppressed = upnpDiscovery.nonCoordinatorMemberUdns()
         val visibleUpnp = upnp
-            .filter { it.id.removePrefix("uuid:") !in suppressed } // suppressed set is bare UDNs
+            .filter { it.id.bareUdn() !in suppressed } // suppressed set is bare UDNs
             .map { OutputRoute.fromUpnpRoute(it) }
         val merged = sys.available + visibleUpnp
         val current = if (upnpSelected != null) {

android/app/src/main/java/com/fabledsword/minstrel/player/output/upnp/UpnpDiscoveryController.kt

@@ -117,12 +117,23 @@ class UpnpDiscoveryController @Inject constructor(
     }
 
     private suspend fun refreshSonosTopology(anySonos: UpnpRoute) {
-        val zgtUrl = anySonos.zoneGroupTopologyControlUrl ?: return
+        val zgtUrl = anySonos.zoneGroupTopologyControlUrl ?: run {
+            Timber.w(
+                "Sonos %s has no ZoneGroupTopology URL -- topology grouping disabled",
+                anySonos.id,
+            )
+            return
+        }
         val groups = runCatching {
             ZoneGroupTopologyClient(SoapClient(okHttp), zgtUrl).getZoneGroupState()
         }
             .onFailure { Timber.w(it, "refreshSonosTopology failed for %s", anySonos.id) }
             .getOrNull() ?: return
+        Timber.w(
+            "Sonos topology refreshed for %s: %d group(s)",
+            anySonos.id,
+            groups.size,
+        )
         sonosTopologyInternal.value = groups
     }
 
@@ -216,7 +227,19 @@ class UpnpDiscoveryController @Inject constructor(
     }
 }
 
-// uuid: prefix normalization — DeviceDescription <UDN> carries it; Sonos
-// ZoneGroupState Coordinator/UUID attrs don't. Helper centralizes the strip
-// so a future change to the convention isn't a silent compare-always-false bug.
-private fun String.bareUdn(): String = removePrefix("uuid:")
+/**
+ * Normalize a Sonos UDN to its bare RINCON form for cross-comparison.
+ *
+ * Three places use UDN strings with different conventions:
+ *  - DeviceDescription's <UDN> tag carries the `uuid:` prefix.
+ *  - Sonos exposes one UDN per embedded device. The MediaRenderer adds
+ *    a `_MR` suffix and the MediaServer adds `_MS`.
+ *  - The ZGT GetZoneGroupState response uses bare `RINCON_xxx` with
+ *    neither the `uuid:` prefix nor any device suffix.
+ *
+ * To compare any pair of those, strip the prefix and the suffix so
+ * everything reduces to the underlying speaker identity.
+ */
+internal fun String.bareUdn(): String = removePrefix("uuid:")
+    .removeSuffix("_MR")
+    .removeSuffix("_MS")

android/app/src/test/java/com/fabledsword/minstrel/player/output/upnp/BareUdnTest.kt

@@ -0,0 +1,44 @@
+package com.fabledsword.minstrel.player.output.upnp
+
+import org.junit.jupiter.api.Test
+import kotlin.test.assertEquals
+
+class BareUdnTest {
+
+    @Test
+    fun `strips uuid prefix`() {
+        assertEquals("RINCON_ABC", "uuid:RINCON_ABC".bareUdn())
+    }
+
+    @Test
+    fun `strips MR suffix`() {
+        assertEquals("RINCON_ABC", "RINCON_ABC_MR".bareUdn())
+    }
+
+    @Test
+    fun `strips MS suffix`() {
+        assertEquals("RINCON_ABC", "RINCON_ABC_MS".bareUdn())
+    }
+
+    @Test
+    fun `strips both uuid prefix and MR suffix`() {
+        assertEquals("RINCON_ABC", "uuid:RINCON_ABC_MR".bareUdn())
+    }
+
+    @Test
+    fun `strips both uuid prefix and MS suffix`() {
+        assertEquals("RINCON_ABC", "uuid:RINCON_ABC_MS".bareUdn())
+    }
+
+    @Test
+    fun `leaves already bare UDN unchanged`() {
+        assertEquals("RINCON_ABC", "RINCON_ABC".bareUdn())
+    }
+
+    @Test
+    fun `MR suffix comparison crosses MediaRenderer vs ZGT response`() {
+        val routeId = "uuid:RINCON_5CAAFD794B6401400_MR"
+        val zgtMemberUdn = "RINCON_5CAAFD794B6401400"
+        assertEquals(routeId.bareUdn(), zgtMemberUdn.bareUdn())
+    }
+}