refactor: extract `ConnectivityManager` methods

app/src/main/java/com/geeksville/mesh/repository/network/ConnectivityManager.kt

@@ -0,0 +1,24 @@
+package com.geeksville.mesh.repository.network
+
+import android.net.ConnectivityManager
+import android.net.Network
+import android.net.NetworkRequest
+import kotlinx.coroutines.channels.awaitClose
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.callbackFlow
+
+internal fun ConnectivityManager.networkAvailable(): Flow<Boolean> = callbackFlow {
+    val callback = object : ConnectivityManager.NetworkCallback() {
+        override fun onAvailable(network: Network) {
+            trySend(allNetworks.isNotEmpty())
+        }
+
+        override fun onLost(network: Network) {
+            trySend(allNetworks.isNotEmpty())
+        }
+    }
+    val networkRequest = NetworkRequest.Builder().build()
+    registerNetworkCallback(networkRequest, callback)
+
+    awaitClose { unregisterNetworkCallback(callback) }
+}

app/src/main/java/com/geeksville/mesh/repository/network/NetworkRepository.kt

@@ -1,19 +1,14 @@
 package com.geeksville.mesh.repository.network
 
 import android.net.ConnectivityManager
-import android.net.Network
-import android.net.NetworkRequest
 import android.net.nsd.NsdManager
 import android.net.nsd.NsdServiceInfo
 import androidx.lifecycle.Lifecycle
 import androidx.lifecycle.coroutineScope
 import com.geeksville.mesh.android.Logging
 import com.geeksville.mesh.CoroutineDispatchers
-import kotlinx.coroutines.channels.awaitClose
-import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.StateFlow
-import kotlinx.coroutines.flow.callbackFlow
 import kotlinx.coroutines.flow.collectLatest
 import kotlinx.coroutines.launch
 import javax.inject.Inject
@@ -27,23 +22,7 @@ class NetworkRepository @Inject constructor(
     private val connectivityManager: dagger.Lazy<ConnectivityManager>,
 ) : Logging {
 
-    private val availableNetworks: HashSet<Network> = HashSet()
-    val networkAvailable: Flow<Boolean> = callbackFlow {
-        val callback = object : ConnectivityManager.NetworkCallback() {
-            override fun onAvailable(network: Network) {
-                availableNetworks.add(network)
-                trySend(availableNetworks.isNotEmpty())
-            }
-
-            override fun onLost(network: Network) {
-                availableNetworks.remove(network)
-                trySend(availableNetworks.isNotEmpty())
-            }
-        }
-        val networkRequest = NetworkRequest.Builder().build()
-        connectivityManager.get().registerNetworkCallback(networkRequest, callback)
-        awaitClose { connectivityManager.get().unregisterNetworkCallback(callback) }
-    }
+    val networkAvailable get() = connectivityManager.get().networkAvailable()
 
     private val _resolvedList = MutableStateFlow<List<NsdServiceInfo>>(emptyList())
     val resolvedList: StateFlow<List<NsdServiceInfo>> get() = _resolvedList