Avoid useless service restart

Restart service with networkCallback only when Internet
is available again.

app/src/main/java/org/unifiedpush/distributor/nextpush/services/RestartNetworkCallback.kt

@@ -15,7 +15,7 @@ class RestartNetworkCallback(val context: Context) : ConnectivityManager.Network
     override fun onAvailable(network: Network) {
         Log.d(TAG, "Network is CONNECTED")
         if (FailureHandler.hasFailed(twice = true, orNeverStart = false)) {
-            Log.d(TAG, "networkCallback: restarting worker")
+            Log.d(TAG, "Available: restarting worker")
             RestartWorker.run(context, delay = 0)
         }
     }
@@ -24,14 +24,23 @@ class RestartNetworkCallback(val context: Context) : ConnectivityManager.Network
         network: Network,
         networkCapabilities: NetworkCapabilities
     ) {
+        if (networkCapabilities.hasCapability(NetworkCapabilities.NET_CAPABILITY_INTERNET)) {
+            if (!hasInternet) {
+                hasInternet = true
                 Log.d(TAG, "Network Capabilities changed")
                 if (FailureHandler.hasFailed(twice = true, orNeverStart = false)) {
-            Log.d(TAG, "networkCallback: restarting worker")
+                    Log.d(TAG, "Internet Cap: restarting worker")
                     RestartWorker.run(context, delay = 0)
                 } // else, it retries in max 2sec
             }
+        } else {
+            hasInternet = false
+        }
+    }
 
     fun register() {
+        if (!registered) {
+            registered = true
             connectivityManager?.let {
                 Log.d(TAG, "ConnectivityManager already registered")
             } ?: run {
@@ -47,10 +56,18 @@ class RestartNetworkCallback(val context: Context) : ConnectivityManager.Network
                 }
             }
         }
+    }
 
     fun unregister() {
         Log.d(TAG, "Unregistering ConnectivityManager")
         connectivityManager?.unregisterNetworkCallback(this)
         connectivityManager = null
+        registered = false
+        hasInternet = false
+    }
+
+    companion object {
+        private var registered = false
+        private var hasInternet = false
     }
 }

app/src/main/java/org/unifiedpush/distributor/nextpush/services/StartService.kt

@@ -50,6 +50,8 @@ class StartService : Service() {
         if (isServiceStarted) {
             Log.d(TAG, "onDestroy: restarting worker")
             RestartWorker.run(this, delay = 0)
+        } else {
+            networkCallback.unregister()
         }
     }