refactor: ensure backward compatibility for PKC encryption

app/src/main/java/com/geeksville/mesh/database/entity/NodeEntity.kt

@@ -79,6 +79,8 @@ data class NodeEntity(
             return (if (brightness > 0.5) Color.BLACK else Color.WHITE) to Color.rgb(r, g, b)
         }
 
+    val hasPKC get() = !user.publicKey.isEmpty
+
     val batteryLevel get() = deviceMetrics.batteryLevel
     val voltage get() = deviceMetrics.voltage
     val batteryStr get() = if (batteryLevel in 1..100) "$batteryLevel%" else ""

app/src/main/java/com/geeksville/mesh/service/MeshService.kt

@@ -474,8 +474,13 @@ class MeshService : Service(), Logging {
 
     /// Admin channel index
     private val adminChannelIndex: Int
-        get() = channelSet.settingsList.indexOfFirst { it.name.equals("admin", ignoreCase = true) }
-            .coerceAtLeast(0)
+        get() = if (nodeDBbyNodeNum[myNodeNum]?.hasPKC == true) { // TODO use meta.hasPKC
+            DataPacket.PKC_CHANNEL_INDEX
+        } else {
+            channelSet.settingsList
+                .indexOfFirst { it.name.equals("admin", ignoreCase = true) }
+                .coerceAtLeast(0)
+        }
 
     /// Generate a new mesh packet builder with our node as the sender, and the specified node num
     private fun newMeshPacketTo(idNum: Int) = MeshPacket.newBuilder().apply {
@@ -513,7 +518,7 @@ class MeshService : Service(), Logging {
         decoded = MeshProtos.Data.newBuilder().also {
             initFn(it)
         }.build()
-        if (decoded.portnum in setOf(Portnums.PortNum.TEXT_MESSAGE_APP, Portnums.PortNum.ADMIN_APP)) {
+        if (channel == DataPacket.PKC_CHANNEL_INDEX) {
             nodeDBbyNodeNum[to]?.user?.publicKey?.let { publicKey ->
                 pkiEncrypted = !publicKey.isEmpty
                 this.publicKey = publicKey

app/src/main/java/com/geeksville/mesh/ui/NodeItem.kt

@@ -75,7 +75,6 @@ fun NodeItem(
     expanded: Boolean = false,
     currentTimeMillis: Long,
 ) {
-    val hasPublicKey = !thatNode.user.publicKey.isEmpty
     val isUnknownUser = thatNode.user.hwModel == MeshProtos.HardwareModel.UNSET
     val unknownShortName = stringResource(id = R.string.unknown_node_short_name)
     val longName = thatNode.user.longName.ifEmpty { stringResource(id = R.string.unknown_username) }
@@ -163,7 +162,7 @@ fun NodeItem(
                         )
                         Text(
                             modifier = Modifier.weight(1f),
-                            text = if (hasPublicKey) "🔒 $longName" else longName,
+                            text = if (thatNode.hasPKC) "🔒 $longName" else longName,
                             style = style,
                             textDecoration = TextDecoration.LineThrough.takeIf { isIgnored },
                             softWrap = true,

app/src/main/java/com/geeksville/mesh/ui/UsersFragment.kt

@@ -90,7 +90,8 @@ class UsersFragment : ScreenFragment("Users"), Logging {
     }
 
     private fun navigateToMessages(node: NodeEntity) = node.user.let { user ->
-        val channel = if (user.publicKey.isEmpty) node.channel else DataPacket.PKC_CHANNEL_INDEX
+        val hasPKC = model.ourNodeInfo.value?.hasPKC == true && node.hasPKC // TODO use meta.hasPKC
+        val channel = if (hasPKC) DataPacket.PKC_CHANNEL_INDEX else node.channel
         val contactKey = "$channel${user.id}"
         info("calling MessagesFragment filter: $contactKey")
         parentFragmentManager.navigateToMessages(contactKey, user.longName)