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Fix mobile BLE scan stream completion and cleanup #8

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Fix mobile BLE scan stream completion and cleanup #8

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29 changes: 28 additions & 1 deletion lib/services/bluetooth/mobile_bluetooth.dart
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Original file line number Diff line number Diff line change
Expand Up @@ -46,6 +46,7 @@ class MobileBluetoothService implements BluetoothService {
StreamSubscription? _connectionStateSubscription;
StreamSubscription? _notificationSubscription;
StreamSubscription? _scanSubscription;
StreamController<DiscoveredDevice>? _scanController;

// Store scanned device info for use in connect()
// This preserves the device name from scan results
Expand Down Expand Up @@ -183,10 +184,15 @@ class MobileBluetoothService implements BluetoothService {
@override
Stream<DiscoveredDevice> scanForDevices({Duration? timeout}) async* {
final controller = StreamController<DiscoveredDevice>();
_scanController = controller;

_updateStatus(ConnectionStatus.scanning);

try {
// Ensure any previous scan stream is closed before starting a new one
await _scanSubscription?.cancel();
_scanSubscription = null;

// Start scanning with filter for MeshCore service UUID
await fbp.FlutterBluePlus.startScan(
withServices: [fbp.Guid(BleUuids.serviceUuid)],
Expand All @@ -208,14 +214,30 @@ class MobileBluetoothService implements BluetoothService {
);
// Store device info for use in connect() - preserves name from scan
_scannedDevices[device.id] = device;
controller.add(device);
if (!controller.isClosed) {
controller.add(device);
}
}
});

// Complete stream when scan naturally stops (timeout or platform stop)
unawaited(() async {
await fbp.FlutterBluePlus.isScanning.where((isScanning) => !isScanning).first;
if (!controller.isClosed) {
await controller.close();
}
}());

yield* controller.stream;
} finally {
await _scanSubscription?.cancel();
_scanSubscription = null;
if (!controller.isClosed) {
await controller.close();
}
if (identical(_scanController, controller)) {
_scanController = null;
}
}
}

Expand All @@ -224,6 +246,11 @@ class MobileBluetoothService implements BluetoothService {
await fbp.FlutterBluePlus.stopScan();
await _scanSubscription?.cancel();
_scanSubscription = null;
final scanController = _scanController;
if (scanController != null && !scanController.isClosed) {
await scanController.close();
}
_scanController = null;
// NOTE: Do NOT fire 'disconnected' here. Stopping a scan is not a disconnection.
// The status will be updated by connect() when a connection starts.
// Firing 'disconnected' here causes a race condition where the queued event
Expand Down