android: add ExitNodeAllowLANAccess toggle in exit node picker (#241)

Updates ENG-3011

Just like on iOS, we should show a switch to toggle the ExitNodeAllowLANAccess preference.

Signed-off-by: Andrea Gottardo <andrea@gottardo.me>

android/src/main/java/com/tailscale/ipn/ui/model/Ipn.kt

@@ -42,7 +42,7 @@ class Ipn {
       var LocalTCPPort: Int? = null,
       var IncomingFiles: List<PartialFile>? = null,
       var ClientVersion: Tailcfg.ClientVersion? = null,
-      var TailFSShares: Map<String, String>? = null,
+      var TailFSShares: List<String>? = null,
   )
 
   @Serializable

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

@@ -109,6 +109,8 @@ fun ExitNodePicker(
                 })
           }
         }
+
+        item("allowLANAccessToggle") { SettingRow(model.allowLANAccessSetting) }
       }
     }
   }

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

@@ -210,7 +210,7 @@ fun SettingsButton(user: IpnLocal.LoginProfile?, action: () -> Unit) {
 fun StartingView() {
   // (jonathan) TODO: On iOS this is the game-of-life Tailscale animation.
   Column(
-      modifier = Modifier.fillMaxSize().background(MaterialTheme.colorScheme.background),
+      modifier = Modifier.fillMaxSize().background(MaterialTheme.colorScheme.secondaryContainer),
       verticalArrangement = Arrangement.Center,
       horizontalAlignment = Alignment.CenterHorizontally) {
         Text(

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

@@ -43,10 +43,7 @@ class DNSSettingsViewModel() : IpnViewModel() {
           isOn = MutableStateFlow(Notifier.prefs.value?.CorpDNS),
           onToggle = {
             LoadingIndicator.start()
-            toggleCorpDNS {
-              LoadingIndicator.stop()
-              // (jonathan) TODO: Error handling
-            }
+            toggleCorpDNS { LoadingIndicator.stop() }
           })
 
   init {

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

@@ -6,6 +6,7 @@ package com.tailscale.ipn.ui.viewModel
 import androidx.lifecycle.ViewModel
 import androidx.lifecycle.ViewModelProvider
 import androidx.lifecycle.viewModelScope
+import com.tailscale.ipn.R
 import com.tailscale.ipn.ui.localapi.Client
 import com.tailscale.ipn.ui.model.Ipn
 import com.tailscale.ipn.ui.model.StableNodeID
@@ -51,7 +52,18 @@ class ExitNodePickerViewModel(private val nav: ExitNodePickerNav) : IpnViewModel
       MutableStateFlow(TreeMap())
   val mullvadBestAvailableByCountry: StateFlow<Map<String, ExitNode>> = MutableStateFlow(TreeMap())
   val anyActive: StateFlow<Boolean> = MutableStateFlow(false)
-    val isRunningExitNode: StateFlow<Boolean> = MutableStateFlow(false)
+  val isRunningExitNode: StateFlow<Boolean> = MutableStateFlow(false)
+
+  val allowLANAccessSetting =
+      Setting(
+          R.string.allow_lan_access,
+          SettingType.SWITCH,
+          isOn = MutableStateFlow(Notifier.prefs.value?.ExitNodeAllowLANAccess),
+          enabled = MutableStateFlow(true),
+          onToggle = {
+            LoadingIndicator.start()
+            toggleAllowLANAccess { LoadingIndicator.stop() }
+          })
 
   init {
     viewModelScope.launch {
@@ -59,7 +71,7 @@ class ExitNodePickerViewModel(private val nav: ExitNodePickerNav) : IpnViewModel
           .combine(Notifier.prefs) { netmap, prefs -> Pair(netmap, prefs) }
           .stateIn(viewModelScope)
           .collect { (netmap, prefs) ->
-              isRunningExitNode.set(prefs?.let { AdvertisedRoutesHelper.exitNodeOnFromPrefs(it) })
+            isRunningExitNode.set(prefs?.let { AdvertisedRoutesHelper.exitNodeOnFromPrefs(it) })
             val exitNodeId = prefs?.ExitNodeID
             netmap?.Peers?.let { peers ->
               val allNodes =
@@ -137,4 +149,17 @@ class ExitNodePickerViewModel(private val nav: ExitNodePickerNav) : IpnViewModel
       LoadingIndicator.stop()
     }
   }
+
+  fun toggleAllowLANAccess(callback: (Result<Ipn.Prefs>) -> Unit) {
+    val prefs =
+        Notifier.prefs.value
+            ?: run {
+              callback(Result.failure(Exception("no prefs")))
+              return@toggleAllowLANAccess
+            }
+
+    val prefsOut = Ipn.MaskedPrefs()
+    prefsOut.ExitNodeAllowLANAccess = !prefs.ExitNodeAllowLANAccess
+    Client(viewModelScope).editPrefs(prefsOut, callback)
+  }
 }

android/src/main/res/values/strings.xml

@@ -124,5 +124,6 @@
     <string name="tailscale_is_not_running_this_device_is_using_the_system_dns_resolver">Tailscale is not running. This device is using the system\'s DNS resolver.</string>
     <string name="this_device_is_using_the_system_dns_resolver">This device is using the system DNS resolver.</string>
     <string name="not_using_tailscale_dns">Not Using Tailscale DNS</string>
+    <string name="allow_lan_access">Allow LAN Access</string>
 
 </resources>