Replay pending actions when connectivity is restored

A raw network drop and recovery never flipped the offline flag, so the
queue only drained on the next sink op, an offline-mode toggle or a
restart. Observe the default network's availability and use it, together
with the persisted offline preference, to trigger a replay. This signal
only drains pending actions; it never changes offline mode.

app/src/main/kotlin/com/subtracks/data/net/NetworkMode.kt

@@ -52,3 +52,29 @@ fun networkMode(context: Context): Flow<NetworkMode> {
         awaitClose { if (registered) runCatching { connectivity?.unregisterNetworkCallback(callback) } }
     }.distinctUntilChanged()
 }
+
+fun networkAvailable(context: Context): Flow<Boolean> {
+    val connectivity = context.applicationContext.getSystemService(ConnectivityManager::class.java)
+    return callbackFlow {
+        fun push() {
+            val capabilities =
+                connectivity?.activeNetwork?.let { connectivity.getNetworkCapabilities(it) }
+            // INTERNET, not VALIDATED: a LAN-only server is reachable without internet validation.
+            trySend(capabilities?.hasCapability(NetworkCapabilities.NET_CAPABILITY_INTERNET) == true)
+        }
+        val callback =
+            object : ConnectivityManager.NetworkCallback() {
+                override fun onAvailable(network: Network) = push()
+
+                override fun onLost(network: Network) = push()
+
+                override fun onCapabilitiesChanged(
+                    network: Network,
+                    capabilities: NetworkCapabilities,
+                ) = push()
+            }
+        val registered = runCatching { connectivity?.registerDefaultNetworkCallback(callback) }.isSuccess
+        push()
+        awaitClose { if (registered) runCatching { connectivity?.unregisterNetworkCallback(callback) } }
+    }.distinctUntilChanged()
+}

app/src/main/kotlin/com/subtracks/data/repo/PendingServerActionSink.kt

@@ -10,6 +10,8 @@ import kotlinx.coroutines.CancellationException
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.combine
+import kotlinx.coroutines.flow.distinctUntilChanged
 import kotlinx.coroutines.flow.first
 import kotlinx.coroutines.launch
 import kotlinx.coroutines.sync.Mutex
@@ -21,20 +23,23 @@ class PendingServerActionSink(
     private val activeSourceId: suspend () -> Long?,
     private val offline: StateFlow<Boolean>,
     offlinePreferences: Flow<Boolean>,
+    networkAvailable: Flow<Boolean>,
     scope: CoroutineScope,
 ) : ServerActionSink {
     private val lock = Mutex()
 
     init {
         scope.launch {
-            offlinePreferences.collect { isOffline ->
-                // The persisted value is authoritative, unlike the process flag's default at cold
-                // start, so wait for that flag to agree before replaying.
-                if (!isOffline) {
-                    offline.first { !it }
-                    flush()
+            combine(offlinePreferences, networkAvailable) { isOffline, online -> !isOffline && online }
+                .distinctUntilChanged()
+                .collect { ready ->
+                    // The persisted flag and connectivity are authoritative, unlike the process
+                    // flag's default at cold start, so wait for that flag to agree before replaying.
+                    if (ready) {
+                        offline.first { !it }
+                        flush()
+                    }
                 }
-            }
         }
     }
 

app/src/main/kotlin/com/subtracks/di/AppModule.kt

@@ -14,6 +14,7 @@ import com.subtracks.data.download.DownloadEngine
 import com.subtracks.data.download.DownloadNotifier
 import com.subtracks.data.download.OkHttpArtworkFetcher
 import com.subtracks.data.download.SystemDownloadEngine
+import com.subtracks.data.net.networkAvailable
 import com.subtracks.data.net.networkMode
 import com.subtracks.data.prefs.UserPreferences
 import com.subtracks.data.prefs.createUserPreferences
@@ -85,6 +86,7 @@ fun appModule(
             activeSourceId = get<SourceRepository>()::activeSourceIdOnce,
             offline = get<SourceRepository>().offline,
             offlinePreferences = get<UserPreferences>().offlineMode(),
+            networkAvailable = networkAvailable(context.applicationContext),
             scope = get(),
         )
     }