android/ui: handle NeedsMachineAuth state

Fixes corp#19119

Adds a variation on the ConnectView to render a header and explainer
text for the NeedsMachineAuth state.  A button to take you directly
to the admin page is presented if you are an admin.

Signed-off-by: Jonathan Nobels <jonathan@tailscale.com>

android/src/main/java/com/tailscale/ipn/ui/view/MainView.kt

@@ -26,7 +26,6 @@ import androidx.compose.material.icons.Icons
 import androidx.compose.material.icons.outlined.ArrowDropDown
 import androidx.compose.material.icons.outlined.Clear
 import androidx.compose.material.icons.outlined.Close
-import androidx.compose.material.icons.outlined.Lock
 import androidx.compose.material.icons.outlined.Search
 import androidx.compose.material.icons.outlined.Settings
 import androidx.compose.material3.Button
@@ -107,6 +106,7 @@ fun MainView(navigation: MainViewNavigation, viewModel: MainViewModel = viewMode
             val stateVal = viewModel.stateRes.collectAsState(initial = R.string.placeholder).value
             val stateStr = stringResource(id = stateVal)
             val netmap = viewModel.netmap.collectAsState(initial = null)
+            val isAdmin = viewModel.isAdmin.collectAsState(initial = false).value
 
             ListItem(
                 colors = MaterialTheme.colorScheme.surfaceContainerListItem,
@@ -163,7 +163,7 @@ fun MainView(navigation: MainViewNavigation, viewModel: MainViewModel = viewMode
               Ipn.State.NoState,
               Ipn.State.Starting -> StartingView()
               else -> {
-                ConnectView(state, user, { viewModel.toggleVpn() }, { viewModel.login {} })
+                ConnectView(state, user, { viewModel.toggleVpn() }, { viewModel.login {} }, isAdmin)
               }
             }
           }
@@ -257,7 +257,8 @@ fun ConnectView(
     state: Ipn.State,
     user: IpnLocal.LoginProfile?,
     connectAction: () -> Unit,
-    loginAction: () -> Unit
+    loginAction: () -> Unit,
+    isAdmin: Boolean,
 ) {
   val handler = LocalUriHandler.current
 
@@ -269,10 +270,6 @@ fun ConnectView(
           horizontalAlignment = Alignment.CenterHorizontally,
       ) {
         if (state == Ipn.State.NeedsMachineAuth) {
-          Icon(
-              modifier = Modifier.size(40.dp),
-              imageVector = Icons.Outlined.Lock,
-              contentDescription = "Device requires authentication")
           Text(
               text = stringResource(id = R.string.machine_auth_required),
               style = MaterialTheme.typography.titleMedium,
@@ -281,12 +278,13 @@ fun ConnectView(
               text = stringResource(id = R.string.machine_auth_explainer),
               style = MaterialTheme.typography.bodyMedium,
               textAlign = TextAlign.Center)
-          Spacer(modifier = Modifier.size(1.dp))
+          if (isAdmin) {
             PrimaryActionButton(onClick = { handler.openUri(Links.ADMIN_URL) }) {
               Text(
                   text = stringResource(id = R.string.open_admin_console),
                   fontSize = MaterialTheme.typography.titleMedium.fontSize)
             }
+          }
         } else if (state != Ipn.State.NeedsLogin && user != null && !user.isEmpty()) {
           Icon(
               painter = painterResource(id = R.drawable.power),

android/src/main/java/com/tailscale/ipn/ui/viewModel/MainViewModel.kt

@@ -34,6 +34,8 @@ class MainViewModel : IpnViewModel() {
   val prefs = Notifier.prefs
   val netmap = Notifier.netmap
 
+  val isAdmin: StateFlow<Boolean> = MutableStateFlow(false)
+
   // The active search term for filtering peers
   val searchTerm: StateFlow<String> = MutableStateFlow("")
 
@@ -53,6 +55,7 @@ class MainViewModel : IpnViewModel() {
         it?.let { netmap ->
           peerCategorizer.regenerateGroupedPeers(netmap)
           peers.set(peerCategorizer.groupedAndFilteredPeers(searchTerm.value))
+          isAdmin.set(netmap.SelfNode.isAdmin)
         }
       }
     }