Reworked writeBytes method

lib/src/enums.dart

@@ -15,6 +15,7 @@ class PosPrintResult {
   static const ticketEmpty = PosPrintResult._internal(4);
   static const printInProgress = PosPrintResult._internal(5);
   static const scanInProgress = PosPrintResult._internal(6);
+  static const error = PosPrintResult._internal(7);
 
   String get msg {
     if (value == PosPrintResult.success.value) {

lib/src/printer_bluetooth_manager.dart

@@ -63,83 +63,83 @@ class PrinterBluetoothManager {
     });
   }
 
-  void stopScan() async {
-    await _bluetoothManager.stopScan();
+  Future<void> stopScan() async {
+    return _bluetoothManager.stopScan();
   }
 
   void selectPrinter(PrinterBluetooth printer) {
     _selectedPrinter = printer;
   }
 
-  Future<PosPrintResult> writeBytes(
-    List<int> bytes, {
-    int chunkSizeBytes = 20,
-    int queueSleepTimeMs = 20,
-  }) async {
-    final Completer<PosPrintResult> completer = Completer();
-
-    const int timeout = 5;
+  Future<PosPrintResult> writeBytes(List<int> bytes,
+      {int chunkSizeBytes = 20,
+      int queueSleepTimeMs = 20,
+      Duration timeout = const Duration(seconds: 5)}) async {
     if (_selectedPrinter == null) {
-      return Future<PosPrintResult>.value(PosPrintResult.printerNotSelected);
+      return PosPrintResult.printerNotSelected;
     } else if (_isScanning.value!) {
-      return Future<PosPrintResult>.value(PosPrintResult.scanInProgress);
+      return PosPrintResult.scanInProgress;
     } else if (_isPrinting) {
-      return Future<PosPrintResult>.value(PosPrintResult.printInProgress);
+      return PosPrintResult.printInProgress;
+    }
+
+    if (!_isConnected) {
+      // We have to rescan before connecting, otherwise we can connect only once
+      await _bluetoothManager.startScan(timeout: Duration(seconds: 1));
+      await _bluetoothManager.stopScan();
+
+      // Connect
+      await _bluetoothManager.connect(_selectedPrinter!._device);
+
+      if (await _bluetoothManager.state
+              .firstWhere((element) => element == BluetoothManager.CONNECTED)
+              .timeout(timeout, onTimeout: () {
+            return BluetoothManager.DISCONNECTED;
+          }) !=
+          BluetoothManager.CONNECTED) {
+        _isConnected = false;
+        return PosPrintResult.timeout;
+      }
+      _isConnected = true;
     }
 
+    final len = bytes.length;
+    List<List<int>> chunks = [];
+    for (var i = 0; i < len; i += chunkSizeBytes) {
+      var end = (i + chunkSizeBytes < len) ? i + chunkSizeBytes : len;
+      chunks.add(bytes.sublist(i, end));
+    }
+
+    List<Future> futures = <Future>[];
+
     _isPrinting = true;
 
-    // We have to rescan before connecting, otherwise we can connect only once
-    await _bluetoothManager.startScan(timeout: Duration(seconds: 1));
-    await _bluetoothManager.stopScan();
-
-    // Connect
-    await _bluetoothManager.connect(_selectedPrinter!._device);
-
-    // Subscribe to the events
-    _bluetoothManager.state.listen((state) async {
-      switch (state) {
-        case BluetoothManager.CONNECTED:
-          // To avoid double call
-          if (!_isConnected) {
-            final len = bytes.length;
-            List<List<int>> chunks = [];
-            for (var i = 0; i < len; i += chunkSizeBytes) {
-              var end = (i + chunkSizeBytes < len) ? i + chunkSizeBytes : len;
-              chunks.add(bytes.sublist(i, end));
-            }
-
-            for (var i = 0; i < chunks.length; i += 1) {
-              await _bluetoothManager.writeData(chunks[i]);
-              sleep(Duration(milliseconds: queueSleepTimeMs));
-            }
-
-            completer.complete(PosPrintResult.success);
-          }
-          // TODO sending disconnect signal should be event-based
-          _runDelayed(3).then((dynamic v) async {
-            await _bluetoothManager.disconnect();
-            _isPrinting = false;
-          });
-          _isConnected = true;
-          break;
-        case BluetoothManager.DISCONNECTED:
-          _isConnected = false;
-          break;
-        default:
-          break;
-      }
-    });
+    for (var i = 0; i < chunks.length; i += 1) {
+      futures.add(_bluetoothManager.writeData(chunks[i]));
+      sleep(Duration(milliseconds: queueSleepTimeMs));
+    }
 
-    // Printing timeout
-    _runDelayed(timeout).then((dynamic v) async {
-      if (_isPrinting) {
-        _isPrinting = false;
-        completer.complete(PosPrintResult.timeout);
-      }
+    await Future.delayed(timeout);
+
+    return Future.wait(futures).then((_) async {
+      _isPrinting = false;
+      return PosPrintResult.success;
+    }).catchError((e) async {
+      _isPrinting = false;
+      _isConnected = false;
+      await _bluetoothManager.disconnect();
+      return PosPrintResult.error;
+    }).timeout(timeout, onTimeout: () async {
+      _isPrinting = false;
+      _isConnected = false;
+      await _bluetoothManager.disconnect();
+      return PosPrintResult.timeout;
     });
+  }
 
-    return completer.future;
+  Future<void> disconnect() async {
+    await _bluetoothManager.disconnect();
+    _isConnected = false;
   }
 
   Future<PosPrintResult> printTicket(

pubspec.yaml

@@ -2,18 +2,21 @@ name: esc_pos_bluetooth
 description: The library allows to print receipts using an ESC/POS thermal Bluetooth printer.
 version: 0.4.1
 homepage: https://github.com/andrey-ushakov/esc_pos_bluetooth
+publish_to: none
 
 environment:
   sdk: ">=2.12.0 <3.0.0"
 
 dependencies:
   flutter:
     sdk: flutter
-  rxdart: ^0.26.0
+  rxdart: ^0.27.7
   esc_pos_utils: ^1.1.0
   # esc_pos_utils:
   # path: ../esc_pos_utils
-  flutter_bluetooth_basic: ^0.1.7
+  flutter_bluetooth_basic:
+    git:
+      url: https://github.com/benlrichards/flutter_bluetooth_basic.git
 
 dev_dependencies:
   flutter_test: