Remove repeater from UI if it's not supported

This could happen on devices like Chrome OS and Android emulators.

mobile/src/main/java/be/mygod/vpnhotspot/BootReceiver.kt

@@ -27,6 +27,8 @@ class BootReceiver : BroadcastReceiver() {
             Intent.ACTION_BOOT_COMPLETED, Intent.ACTION_LOCKED_BOOT_COMPLETED -> started = true
             else -> return
         }
+        if (RepeaterService.supported) {
             ContextCompat.startForegroundService(context, Intent(context, RepeaterService::class.java))
         }
+    }
 }

mobile/src/main/java/be/mygod/vpnhotspot/RepeaterService.kt

@@ -27,13 +27,28 @@ import be.mygod.vpnhotspot.widget.SmartSnackbar
 import timber.log.Timber
 import java.lang.reflect.InvocationTargetException
 
+/**
+ * Service for handling Wi-Fi P2P. `supported` must be checked before this service is started otherwise it would crash.
+ */
 class RepeaterService : Service(), WifiP2pManager.ChannelListener, SharedPreferences.OnSharedPreferenceChangeListener {
     companion object {
         private const val TAG = "RepeaterService"
+        /**
+         * This is only a "ServiceConnection" to system service and its impact on system is minimal.
+         */
+        private val p2pManager: WifiP2pManager? by lazy {
+            try {
+                app.getSystemService<WifiP2pManager>()
+            } catch (e: RuntimeException) {
+                Timber.w(e)
+                null
+            }
+        }
+        val supported get() = p2pManager != null
     }
 
     enum class Status {
-        IDLE, STARTING, ACTIVE
+        IDLE, STARTING, ACTIVE, DESTROYED
     }
 
     inner class Binder : android.os.Binder() {
@@ -92,7 +107,7 @@ class RepeaterService : Service(), WifiP2pManager.ChannelListener, SharedPrefere
         }
     }
 
-    private lateinit var p2pManager: WifiP2pManager
+    private val p2pManager get() = RepeaterService.p2pManager!!
     private var channel: WifiP2pManager.Channel? = null
     var group: WifiP2pGroup? = null
         private set(value) {
@@ -138,12 +153,7 @@ class RepeaterService : Service(), WifiP2pManager.ChannelListener, SharedPrefere
 
     override fun onCreate() {
         super.onCreate()
-        try {
-            p2pManager = getSystemService()!!
         onChannelDisconnected()
-        } catch (e: RuntimeException) {
-            Timber.w(e)
-        }
         app.pref.registerOnSharedPreferenceChangeListener(this)
     }
 
@@ -169,7 +179,7 @@ class RepeaterService : Service(), WifiP2pManager.ChannelListener, SharedPrefere
 
     override fun onChannelDisconnected() {
         channel = null
-        try {
+        if (status != Status.DESTROYED) try {
             channel = p2pManager.initialize(this, Looper.getMainLooper(), this)
             setOperatingChannel()
             binder.requestGroupUpdate()
@@ -282,6 +292,8 @@ class RepeaterService : Service(), WifiP2pManager.ChannelListener, SharedPrefere
         if (status != Status.IDLE) binder.shutdown()
         clean() // force clean to prevent leakage
         app.pref.unregisterOnSharedPreferenceChangeListener(this)
+        status = Status.DESTROYED
+        channel?.close()
         super.onDestroy()
     }
 }

mobile/src/main/java/be/mygod/vpnhotspot/RepeaterTileService.kt

@@ -22,12 +22,14 @@ class RepeaterTileService : TileService(), ServiceConnection {
 
     override fun onStartListening() {
         super.onStartListening()
+        if (RepeaterService.supported) {
             bindService(Intent(this, RepeaterService::class.java), this, Context.BIND_AUTO_CREATE)
         }
+    }
 
     override fun onStopListening() {
         super.onStopListening()
-        stopAndUnbind(this)
+        if (RepeaterService.supported) stopAndUnbind(this)
     }
 
     override fun onClick() {
@@ -72,7 +74,7 @@ class RepeaterTileService : TileService(), ServiceConnection {
                 qsTile.icon = tileOn
                 qsTile.label = group?.networkName
             }
-            null -> {
+            else -> {   // null or DESTROYED, which should never occur
                 qsTile.state = Tile.STATE_UNAVAILABLE
                 qsTile.icon = tileOff
                 qsTile.label = getString(R.string.title_repeater)

mobile/src/main/java/be/mygod/vpnhotspot/SettingsPreferenceFragment.kt

@@ -32,11 +32,13 @@ class SettingsPreferenceFragment : PreferenceFragmentCompat() {
         preferenceManager.preferenceDataStore = SharedPreferenceDataStore(app.pref)
         addPreferencesFromResource(R.xml.pref_settings)
         val boot = findPreference("service.repeater.startOnBoot") as SwitchPreference
+        if (RepeaterService.supported) {
             boot.setOnPreferenceChangeListener { _, value ->
                 BootReceiver.enabled = value as Boolean
                 true
             }
             boot.isChecked = BootReceiver.enabled
+        } else boot.parent!!.removePreference(boot)
         findPreference("service.clean").setOnPreferenceClickListener {
             val cleaned = try {
                 Routing.clean()

mobile/src/main/java/be/mygod/vpnhotspot/client/ClientMonitorService.kt

@@ -64,7 +64,9 @@ class ClientMonitorService : Service(), ServiceConnection, IpNeighbourMonitor.Ca
 
     override fun onCreate() {
         super.onCreate()
+        if (RepeaterService.supported) {
             bindService(Intent(this, RepeaterService::class.java), this, Context.BIND_AUTO_CREATE)
+        }
         IpNeighbourMonitor.registerCallback(this)
         registerReceiver(receiver, IntentFilter(TetheringManager.ACTION_TETHER_STATE_CHANGED))
     }
@@ -72,7 +74,7 @@ class ClientMonitorService : Service(), ServiceConnection, IpNeighbourMonitor.Ca
     override fun onDestroy() {
         unregisterReceiver(receiver)
         IpNeighbourMonitor.unregisterCallback(this)
-        stopAndUnbind(this)
+        if (RepeaterService.supported) stopAndUnbind(this)
         super.onDestroy()
     }
 

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

@@ -20,6 +20,7 @@ import androidx.recyclerview.widget.ListAdapter
 import androidx.recyclerview.widget.RecyclerView
 import be.mygod.vpnhotspot.LocalOnlyHotspotService
 import be.mygod.vpnhotspot.R
+import be.mygod.vpnhotspot.RepeaterService
 import be.mygod.vpnhotspot.TetheringService
 import be.mygod.vpnhotspot.databinding.FragmentTetheringBinding
 import be.mygod.vpnhotspot.net.TetherType
@@ -59,7 +60,8 @@ class TetheringFragment : Fragment(), ServiceConnection {
             this@TetheringFragment.enabledTypes =
                     (activeIfaces + localOnlyIfaces).map { TetherType.ofInterface(it) }.toSet()
 
-            val list = arrayListOf<Manager>(repeaterManager)
+            val list = ArrayList<Manager>()
+            if (RepeaterService.supported) list.add(repeaterManager)
             if (Build.VERSION.SDK_INT >= 26) {
                 list.add(localOnlyHotspotManager)
                 localOnlyHotspotManager.update()