Add Bluetooth on/off into consideration when using Bluetooth tethering

mobile/src/main/java/be/mygod/vpnhotspot/manage/BluetoothTethering.kt

@@ -1,14 +1,23 @@
 package be.mygod.vpnhotspot.manage
 
 import android.annotation.SuppressLint
+import android.annotation.TargetApi
 import android.bluetooth.BluetoothAdapter
 import android.bluetooth.BluetoothProfile
+import android.content.BroadcastReceiver
 import android.content.Context
+import android.content.Intent
+import android.content.IntentFilter
+import androidx.annotation.RequiresApi
+import be.mygod.vpnhotspot.App.Companion.app
+import be.mygod.vpnhotspot.net.TetheringManager
+import be.mygod.vpnhotspot.util.broadcastReceiver
 import be.mygod.vpnhotspot.widget.SmartSnackbar
 import timber.log.Timber
 
-class BluetoothTethering(context: Context) : BluetoothProfile.ServiceListener, AutoCloseable {
-    companion object {
+class BluetoothTethering(context: Context, val stateListener: (Int) -> Unit) :
+        BluetoothProfile.ServiceListener, AutoCloseable {
+    companion object : BroadcastReceiver() {
         /**
          * PAN Profile
          * From BluetoothProfile.java.
@@ -17,6 +26,42 @@ class BluetoothTethering(context: Context) : BluetoothProfile.ServiceListener, A
         private val isTetheringOn by lazy @SuppressLint("PrivateApi") {
             Class.forName("android.bluetooth.BluetoothPan").getDeclaredMethod("isTetheringOn")
         }
+
+        private fun registerBluetoothStateListener(receiver: BroadcastReceiver) =
+                app.registerReceiver(receiver, IntentFilter(BluetoothAdapter.ACTION_STATE_CHANGED))
+        private val Intent.bluetoothState get() = getIntExtra(BluetoothAdapter.EXTRA_STATE, BluetoothAdapter.ERROR)
+
+        private var pendingCallback: TetheringManager.OnStartTetheringCallback? = null
+
+        /**
+         * https://android.googlesource.com/platform/packages/apps/Settings/+/b1af85d/src/com/android/settings/TetherSettings.java#215
+         */
+        @TargetApi(24)
+        override fun onReceive(context: Context?, intent: Intent?) {
+            when (intent?.bluetoothState) {
+                BluetoothAdapter.STATE_ON -> {
+                    TetheringManager.start(TetheringManager.TETHERING_BLUETOOTH, true, pendingCallback!!)
+                }
+                BluetoothAdapter.STATE_OFF, BluetoothAdapter.ERROR -> { }
+                else -> return  // ignore transition states
+            }
+            pendingCallback = null
+            app.unregisterReceiver(this)
+        }
+
+        /**
+         * https://android.googlesource.com/platform/packages/apps/Settings/+/b1af85d/src/com/android/settings/TetherSettings.java#384
+         */
+        @RequiresApi(24)
+        fun start(callback: TetheringManager.OnStartTetheringCallback) {
+            if (pendingCallback != null) return
+            val adapter = BluetoothAdapter.getDefaultAdapter()
+            if (adapter?.state == BluetoothAdapter.STATE_OFF) {
+                registerBluetoothStateListener(this)
+                pendingCallback = callback
+                adapter.enable()
+            } else TetheringManager.start(TetheringManager.TETHERING_BLUETOOTH, true, callback)
+        }
     }
 
     private var pan: BluetoothProfile? = null
@@ -29,6 +74,8 @@ class BluetoothTethering(context: Context) : BluetoothProfile.ServiceListener, A
                 isTetheringOn.invoke(pan) as Boolean
     }
 
+    private val receiver = broadcastReceiver { _, intent -> stateListener(intent.bluetoothState) }
+
     init {
         try {
             BluetoothAdapter.getDefaultAdapter()?.getProfileProxy(context, this, PAN)
@@ -36,6 +83,7 @@ class BluetoothTethering(context: Context) : BluetoothProfile.ServiceListener, A
             Timber.w(e)
             SmartSnackbar.make(e).show()
         }
+        registerBluetoothStateListener(receiver)
     }
 
     override fun onServiceDisconnected(profile: Int) {

mobile/src/main/java/be/mygod/vpnhotspot/manage/TetherListeningTileService.kt

@@ -3,6 +3,7 @@ package be.mygod.vpnhotspot.manage
 import android.content.IntentFilter
 import androidx.annotation.RequiresApi
 import be.mygod.vpnhotspot.net.TetheringManager
+import be.mygod.vpnhotspot.net.TetheringManager.tetheredIfaces
 import be.mygod.vpnhotspot.util.KillableTileService
 import be.mygod.vpnhotspot.util.broadcastReceiver
 
@@ -11,14 +12,14 @@ abstract class TetherListeningTileService : KillableTileService() {
     protected var tethered: List<String> = emptyList()
 
     private val receiver = broadcastReceiver { _, intent ->
-        tethered = TetheringManager.getTetheredIfaces(intent.extras ?: return@broadcastReceiver)
+        tethered = intent.tetheredIfaces
         updateTile()
     }
 
     override fun onStartListening() {
         super.onStartListening()
-        tethered = TetheringManager.getTetheredIfaces(registerReceiver(
-                receiver, IntentFilter(TetheringManager.ACTION_TETHER_STATE_CHANGED))?.extras ?: return)
+        val intent = registerReceiver(receiver, IntentFilter(TetheringManager.ACTION_TETHER_STATE_CHANGED))
+        if (intent != null) tethered = intent.tetheredIfaces
     }
 
     override fun onStopListening() {

mobile/src/main/java/be/mygod/vpnhotspot/manage/TetherManager.kt

@@ -149,7 +149,7 @@ sealed class TetherManager(protected val parent: TetheringFragment) : Manager(),
     }
     @RequiresApi(24)
     class Bluetooth(parent: TetheringFragment) : TetherManager(parent), LifecycleObserver {
-        private val tethering = BluetoothTethering(parent.requireContext())
+        private val tethering = BluetoothTethering(parent.requireContext()) { onTetheringStarted() }
 
         init {
             parent.lifecycle.addObserver(this)
@@ -163,7 +163,7 @@ sealed class TetherManager(protected val parent: TetheringFragment) : Manager(),
         override val type get() = VIEW_TYPE_BLUETOOTH
         override val isStarted get() = tethering.active == true
 
-        override fun start() = TetheringManager.start(TetheringManager.TETHERING_BLUETOOTH, true, this)
+        override fun start() = BluetoothTethering.start(this)
         override fun stop() {
             TetheringManager.stop(TetheringManager.TETHERING_BLUETOOTH)
             Thread.sleep(1)         // give others a room to breathe

mobile/src/main/java/be/mygod/vpnhotspot/manage/TetheringFragment.kt

@@ -21,6 +21,8 @@ import be.mygod.vpnhotspot.*
 import be.mygod.vpnhotspot.databinding.FragmentTetheringBinding
 import be.mygod.vpnhotspot.net.TetherType
 import be.mygod.vpnhotspot.net.TetheringManager
+import be.mygod.vpnhotspot.net.TetheringManager.localOnlyTetheredIfaces
+import be.mygod.vpnhotspot.net.TetheringManager.tetheredIfaces
 import be.mygod.vpnhotspot.util.ServiceForegroundConnector
 import be.mygod.vpnhotspot.util.broadcastReceiver
 import kotlinx.android.synthetic.main.activity_main.*
@@ -88,10 +90,8 @@ class TetheringFragment : Fragment(), ServiceConnection, MenuItem.OnMenuItemClic
     var binder: TetheringService.Binder? = null
     private val adapter = ManagerAdapter()
     private val receiver = broadcastReceiver { _, intent ->
-        val extras = intent.extras ?: return@broadcastReceiver
-        adapter.update(TetheringManager.getTetheredIfaces(extras),
-                TetheringManager.getLocalOnlyTetheredIfaces(extras),
-                extras.getStringArrayList(TetheringManager.EXTRA_ERRORED_TETHER)!!)
+        adapter.update(intent.tetheredIfaces, intent.localOnlyTetheredIfaces,
+                intent.getStringArrayListExtra(TetheringManager.EXTRA_ERRORED_TETHER))
     }
 
     private fun updateMonitorList(canMonitor: List<String> = emptyList()) {

mobile/src/main/java/be/mygod/vpnhotspot/manage/TetheringTileService.kt

@@ -127,7 +127,7 @@ sealed class TetheringTileService : TetherListeningTileService(), TetheringManag
         override val labelString get() = R.string.tethering_manage_bluetooth
         override val tetherType get() = TetherType.BLUETOOTH
 
-        override fun start() = TetheringManager.start(TetheringManager.TETHERING_BLUETOOTH, true, this)
+        override fun start() = BluetoothTethering.start(this)
         override fun stop() {
             TetheringManager.stop(TetheringManager.TETHERING_BLUETOOTH)
             Thread.sleep(1)         // give others a room to breathe
@@ -135,7 +135,7 @@ sealed class TetheringTileService : TetherListeningTileService(), TetheringManag
         }
 
         override fun onStartListening() {
-            tethering = BluetoothTethering(this)
+            tethering = BluetoothTethering(this) { updateTile() }
             super.onStartListening()
         }
         override fun onStopListening() {