Fix networkname retrieval for some wifi devices (#535)

matter_server/client/client.py

@@ -10,6 +10,7 @@
 
 from aiohttp import ClientSession
 from chip.clusters import Objects as Clusters
+from chip.clusters.Types import NullValue
 
 from matter_server.common.errors import ERROR_MAP, NodeNotExists
 
@@ -258,6 +259,7 @@ async def ping_node(self, node_id: int) -> NodePingResult:
 
     async def node_diagnostics(self, node_id: int) -> NodeDiagnostics:
         """Gather diagnostics for the given node."""
+        # pylint: disable=too-many-statements
         node = self.get_node(node_id)
         # grab some details from the first (operational) network interface
         network_type = NetworkType.UNKNOWN
@@ -307,7 +309,7 @@ async def node_diagnostics(self, node_id: int) -> NodeDiagnostics:
             )
             if isinstance(thread_cluster.networkName, bytes):
                 network_name = thread_cluster.networkName.decode("utf-8")
-            else:
+            elif thread_cluster.networkName != NullValue:
                 network_name = thread_cluster.networkName
             # parse routing role to (diagnostics) node type
             if (
@@ -339,8 +341,27 @@ async def node_diagnostics(self, node_id: int) -> NodeDiagnostics:
         ):
             if isinstance(last_network_id, bytes):
                 network_name = last_network_id.decode("utf-8")
-            else:
+            elif last_network_id != NullValue:
                 network_name = last_network_id
+        # last resort to get the (wifi) networkname;
+        # enumerate networks on the NetworkCommissioning cluster
+        networks: list[Clusters.NetworkCommissioning.Structs.NetworkInfoStruct]
+        if not network_name and (
+            networks := node.get_attribute_value(
+                0,
+                cluster=None,
+                attribute=Clusters.NetworkCommissioning.Attributes.Networks,
+            )
+        ):
+            for network in networks:
+                if not network.connected:
+                    continue
+                if isinstance(network.networkID, bytes):
+                    network_name = network.networkID.decode("utf-8")
+                    break
+                if network.networkID != NullValue:
+                    network_name = network.networkID
+                    break
         # override node type if node is a bridge
         if node.node_data.is_bridge:
             node_type = NodeType.BRIDGE