fix(android): Sonos ZGT robust extraction -- escaped + nested element fallback + diag

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

@@ -99,7 +99,7 @@ class SoapClient(
             } else {
                 if (inResponse) {
                     val name = parser.name
-                    val text = runCatching { parser.nextText() }.getOrDefault("")
+                    val text = readElementContent(parser, name)
                     args[name] = text
                 }
                 inResponse
@@ -109,6 +109,51 @@ class SoapClient(
         else -> inResponse
     }
 
+    /**
+     * Read the content of the currently-started element. Try nextText() first
+     * (works when the content is text -- escaped XML included). If that throws
+     * (because the content is nested elements), manually walk to the matching
+     * END_TAG, accumulating text and re-serializing child elements.
+     *
+     * Some Sonos firmware sends the GetZoneGroupState payload as nested XML
+     * elements without escaping; this fallback recovers that path.
+     */
+    private fun readElementContent(parser: XmlPullParser, tagName: String): String {
+        return runCatching { parser.nextText() }.getOrElse {
+            readUntilEndTag(parser, tagName)
+        }
+    }
+
+    private fun readUntilEndTag(parser: XmlPullParser, tagName: String): String {
+        val sb = StringBuilder()
+        var depth = 1
+        while (depth > 0) {
+            when (parser.next()) {
+                XmlPullParser.START_TAG -> {
+                    sb.append('<').append(parser.name)
+                    for (i in 0 until parser.attributeCount) {
+                        sb.append(' ')
+                            .append(parser.getAttributeName(i))
+                            .append("=\"")
+                            .append(parser.getAttributeValue(i))
+                            .append('"')
+                    }
+                    sb.append('>')
+                    depth += 1
+                }
+                XmlPullParser.END_TAG -> {
+                    depth -= 1
+                    if (depth == 0 && parser.name == tagName) break
+                    sb.append("</").append(parser.name).append('>')
+                }
+                XmlPullParser.TEXT -> sb.append(parser.text.orEmpty())
+                XmlPullParser.END_DOCUMENT -> break
+                else -> Unit
+            }
+        }
+        return sb.toString()
+    }
+
     private fun faultCodeOf(body: String): String =
         extractBetween(body, "<errorCode>", "</errorCode>") ?: "unknown"
 
@@ -141,23 +186,32 @@ private const val MAX_BODY_LOG_CHARS = 2048
 
 /**
  * Returns a [SoapClient] that logs the raw response body for the first
- * [MAX_DIAGNOSTIC_RESPONSES] GetPositionInfo / GetTransportInfo calls (i.e.
- * the first 3 poll cycles of a UPnP session). After that the callback is a
- * no-op so there is no persistent log spam. Logged at WARN so release builds
- * capture it without a separate log-level override.
+ * [MAX_DIAGNOSTIC_RESPONSES] calls for actions in [DIAGNOSTIC_ACTIONS]
+ * (GetPositionInfo, GetTransportInfo, GetZoneGroupState). After that the
+ * callback is a no-op so there is no persistent log spam. Logged at WARN
+ * so release builds capture it without a separate log-level override.
  */
 internal fun loggingSoapClient(okHttp: OkHttpClient, label: String): SoapClient {
     val counter = AtomicInteger(0)
     return SoapClient(okHttp) { action, body ->
-        if (action != "GetPositionInfo" && action != "GetTransportInfo") return@SoapClient
+        if (action !in DIAGNOSTIC_ACTIONS) return@SoapClient
         val n = counter.incrementAndGet()
         if (n <= MAX_DIAGNOSTIC_RESPONSES) {
-            Timber.w("UPnP %s response #%d (%s): %s",
-                label, n, action, body.take(MAX_BODY_LOG_CHARS))
+            Timber.w(
+                "UPnP %s response #%d (%s): %s",
+                label, n, action,
+                body.take(MAX_BODY_LOG_CHARS),
+            )
         }
     }
 }
 
+private val DIAGNOSTIC_ACTIONS = setOf(
+    "GetPositionInfo",
+    "GetTransportInfo",
+    "GetZoneGroupState",
+)
+
 /** XML-escapes a string value for embedding as text content inside a SOAP envelope. */
 internal fun xmlEscape(v: String): String = v
     .replace("&", "&amp;")

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

@@ -125,7 +125,10 @@ class UpnpDiscoveryController @Inject constructor(
             return
         }
         val groups = runCatching {
-            ZoneGroupTopologyClient(SoapClient(okHttp), zgtUrl).getZoneGroupState()
+            ZoneGroupTopologyClient(
+                loggingSoapClient(okHttp, "ZGT-${anySonos.id}"),
+                zgtUrl,
+            ).getZoneGroupState()
         }
             .onFailure { Timber.w(it, "refreshSonosTopology failed for %s", anySonos.id) }
             .getOrNull() ?: return

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

@@ -24,9 +24,21 @@ data class SonosZoneMember(
 object SonosTopology {
 
     fun parse(xml: String): List<SonosZoneGroup> {
-        return runCatching { parseStrict(xml) }.getOrDefault(emptyList())
+        val effective = if (xml.contains("&lt;ZoneGroup")) {
+            unescapeXmlEntities(xml)
+        } else {
+            xml
+        }
+        return runCatching { parseStrict(effective) }.getOrDefault(emptyList())
     }
 
+    private fun unescapeXmlEntities(s: String): String = s
+        .replace("&lt;", "<")
+        .replace("&gt;", ">")
+        .replace("&quot;", "\"")
+        .replace("&apos;", "'")
+        .replace("&amp;", "&")  // must be last to avoid double-decoding
+
     private fun parseStrict(xml: String): List<SonosZoneGroup> {
         val parser = XmlPullParserFactory.newInstance().newPullParser().apply {
             setInput(xml.reader())

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

@@ -2,6 +2,7 @@ package com.fabledsword.minstrel.player.output.upnp.sonos
 
 import com.fabledsword.minstrel.player.output.upnp.SoapClient
 import okhttp3.HttpUrl
+import timber.log.Timber
 
 /**
  * Sonos's proprietary ZoneGroupTopology service. Same SOAP shape as a
@@ -21,10 +22,16 @@ class ZoneGroupTopologyClient(
             args = emptyMap(),
         )
         val inner = args["ZoneGroupState"].orEmpty()
+        Timber.w(
+            "ZGT extracted ZoneGroupState (%d chars): %s",
+            inner.length,
+            inner.take(ZGT_LOG_TRUNCATE_CHARS),
+        )
         return SonosTopology.parse(inner)
     }
 
     private companion object {
         const val SERVICE_TYPE = "urn:schemas-upnp-org:service:ZoneGroupTopology:1"
+        const val ZGT_LOG_TRUNCATE_CHARS = 2048
     }
 }

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

@@ -71,4 +71,39 @@ class SonosTopologyTest {
     fun `malformed xml returns empty list`() {
         assertEquals(emptyList(), SonosTopology.parse("<garbage"))
     }
+
+    @Test
+    fun `parses inline non-escaped ZoneGroupState document`() {
+        // Some Sonos firmware sends the topology as nested elements with
+        // no escaping. After SoapClient.readUntilEndTag rebuilds a flat
+        // string, parse should still find the groups.
+        val xml = """
+            <ZoneGroupState>
+              <ZoneGroups>
+                <ZoneGroup Coordinator="RINCON_A" ID="RINCON_A:1">
+                  <ZoneGroupMember UUID="RINCON_A" ZoneName="Kitchen"
+                    Location="http://192.168.1.10:1400/xml/device_description.xml"/>
+                </ZoneGroup>
+              </ZoneGroups>
+            </ZoneGroupState>
+        """.trimIndent()
+        val groups = SonosTopology.parse(xml)
+        assertEquals(1, groups.size)
+    }
+
+    @Test
+    fun `parses escaped ZoneGroupState wrapped in entities`() {
+        val xml = """
+            &lt;ZoneGroupState&gt;
+              &lt;ZoneGroups&gt;
+                &lt;ZoneGroup Coordinator="RINCON_A" ID="RINCON_A:1"&gt;
+                  &lt;ZoneGroupMember UUID="RINCON_A" ZoneName="Kitchen"
+                    Location="http://192.168.1.10:1400/xml/device_description.xml"/&gt;
+                &lt;/ZoneGroup&gt;
+              &lt;/ZoneGroups&gt;
+            &lt;/ZoneGroupState&gt;
+        """.trimIndent()
+        val groups = SonosTopology.parse(xml)
+        assertEquals(1, groups.size)
+    }
 }