Commit 6951e93

@@ -0,0 +1,73 @@
+import 'dart:async';
+
+import 'package:blood_pressure_app/bluetooth/flutter_blue_plus_mockable.dart';
+import 'package:blood_pressure_app/bluetooth/logging.dart';
+import 'package:collection/collection.dart';
+import 'package:flutter/cupertino.dart';
+import 'package:flutter/foundation.dart';
+import 'package:flutter_bloc/flutter_bloc.dart';
+import 'package:flutter_blue_plus/flutter_blue_plus.dart';
+
+part 'ble_read_state.dart';
+
+/// Logic for reading a characteristic from a device.
+///
+/// May only be used on devices that are fully connected.
+class BleReadCubit extends Cubit<BleRead> {
+  /// Start reading a characteristic from a device.
+  BleReadCubit(this._flutterBluePlus, this._device)
+    : super(BleReadInProgress()) {
+   unawaited(_startRead());
+  }
+
+  final FlutterBluePlusMockable _flutterBluePlus;
+
+  /// Bluetooth device to connect to.
+  ///
+  /// Must have an active established connection and support the measurement
+  /// characteristic.
+  final BluetoothDevice _device;
+
+  Future<void> _startRead() async {
+    // Query actual services supported by the device. While they must be
+    // rediscovered when a disconnect happens, this object is also recreated.
+    late final List<BluetoothService> allServices;
+    try {
+      allServices = await _device.discoverServices();
+    } catch (e) {
+      emit(BleReadFailure());
+      Log.err('service discovery', [_device, e]);
+    }
+
+
+    // [Guid.str] trims standard parts from the uuid. 0x1810 is the blood
+    // pressure uuid. https://developer.nordicsemi.com/nRF51_SDK/nRF51_SDK_v4.x.x/doc/html/group___u_u_i_d___s_e_r_v_i_c_e_s.html
+    final service = allServices.firstWhereOrNull((s) => s.uuid.str == '1810');
+    if (service == null) {
+      Log.err('unsupported service', [_device, allServices]);
+      emit(BleReadFailure());
+      return;
+    }
+
+    // https://developer.nordicsemi.com/nRF51_SDK/nRF51_SDK_v4.x.x/doc/html/group___u_u_i_d___c_h_a_r_a_c_t_e_r_i_s_t_i_c_s.html#ga95fc99c7a99cf9d991c81027e4866936
+    final allCharacteristics = service.characteristics;
+    final characteristic = allCharacteristics.firstWhereOrNull(
+            (c) => c.uuid.str == '2A35');
+    if (characteristic == null) {
+      emit(BleReadFailure());
+      Log.err('no characteristic', [_device, allServices, allCharacteristics]);
+      return;
+    }
+
+    late final List<int> data;
+    try {
+      data = await characteristic.read();
+    } catch (e) {
+      emit(BleReadFailure());
+      Log.err('read error', [_device, allServices, characteristic, e]);
+    }
+
+    // TODO: decode data before emitting success.
+    emit(BleReadSuccess(data));
+  }
+}

@@ -0,0 +1,20 @@
+part of 'ble_read_cubit.dart';
+
+/// State of reading a characteristic from a BLE device.
+@immutable
+abstract class BleRead {}
+
+/// The reading has been started.
+class BleReadInProgress extends BleRead {}
+
+/// The reading failed unrecoverable for some reason.
+class BleReadFailure extends BleRead {}
+
+/// Data has been successfully read.
+class BleReadSuccess extends BleRead {
+  /// Indicate a successful reading of a ble characteristic.
+  BleReadSuccess(this.data);
+
+  /// Raw binary data received from the device.
+  final List<int> data;
+}

@@ -56,8 +56,11 @@ class DeviceScanCubit extends Cubit<DeviceScanState> {
     );
     try {
       await _flutterBluePlus.startScan(
-        withServices: [service],
         // no timeout, the user knows best how long scanning is needed
+        withServices: [service],
+        // Might not find the device (https://pub.dev/packages/flutter_blue_plus#scanning-does-not-find-my-device)
+        // TODO: Make decision on whether to support these devices
+
       );
     } catch (e) {
       _onScanError(e);

@@ -0,0 +1,17 @@
+import 'package:dump/dump.dart'; // only used in debug mode
+import 'package:flutter/foundation.dart';
+
+/// Simple class for manually logging in debug builds.
+class Log {
+  /// Log an error with stack trace in debug builds.
+  static void err(String message, [List<Object>? dumps]) {
+    if (kDebugMode) {
+      debugPrint('-----------------------------');
+      debugPrintStack();
+      debugPrint('ERROR $message:');
+      for (final e in dumps ?? []) {
+        dumpJson(e);
+      }
+    }
+  }
+}
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@@ -0,0 +1,107 @@
+import 'dart:async';
+
+import 'package:flutter_blue_plus/flutter_blue_plus.dart';
+
+class BeforeScanning {
+  late StreamSubscription<BluetoothAdapterState> _adapterStateStateSubscription;
+
+  // Must be: `on`
+  BluetoothAdapterState _adapterState = BluetoothAdapterState.unknown;
+
+  init() {
+    _adapterStateStateSubscription = FlutterBluePlus.adapterState.listen((state) {
+      setState(() {
+        _adapterState = state;
+      });
+    });
+  }
+
+  dispose() {
+    _adapterStateStateSubscription.cancel();
+  }
+
+  enableBluetooth() {
+    try {
+      if (Platform.isAndroid) {
+        await FlutterBluePlus.turnOn();
+      }
+    } catch (e) {
+      Snackbar.show(ABC.a, prettyException("Error Turning On:", e), success: false);
+    }
+  }
+}
+
+class ScanningPhase {
+  List<BluetoothDevice> _systemDevices = [];
+  List<ScanResult> _scanResults = [];
+  bool _isScanning = false;
+  late StreamSubscription<List<ScanResult>> _scanResultsSubscription;
+  late StreamSubscription<bool> _isScanningSubscription;
+
+  initState() {
+    super.initState();
+
+    _scanResultsSubscription = FlutterBluePlus.scanResults.listen((results) {
+      _scanResults = results;
+    }, onError: (e) {
+      Snackbar.show(ABC.b, prettyException("Scan Error:", e), success: false);
+    });
+
+    _isScanningSubscription = FlutterBluePlus.isScanning.listen((state) {
+      _isScanning = state;
+    });
+  }
+
+  dispose() {
+    _scanResultsSubscription.cancel();
+    _isScanningSubscription.cancel();
+    super.dispose();
+  }
+
+  onScanPressed() async {
+    try {
+      _systemDevices = await FlutterBluePlus.systemDevices;
+    } catch (e) {
+      Snackbar.show(ABC.b, prettyException("System Devices Error:", e), success: false);
+    }
+    try {
+      await FlutterBluePlus.startScan(timeout: const Duration(seconds: 15));
+    } catch (e) {
+      Snackbar.show(ABC.b, prettyException("Start Scan Error:", e), success: false);
+    }
+  }
+
+  onStopPressed() async {
+    try {
+      FlutterBluePlus.stopScan();
+    } catch (e) {
+      Snackbar.show(ABC.b, prettyException("Stop Scan Error:", e), success: false);
+    }
+  }
+}
+
+class DeviceInfo {
+
+  userInfo() {
+    widget.result._device.platformName.isNotEmpty
+        ? widget.result._device.platformName
+        : widget.result._device.remoteId.str
+  }
+
+  bool get isConnectable => widget.result.advertisementData.connectable;
+
+  connect() {
+    _device.connectAndUpdateStream().catchError((e) {
+      Snackbar.show(ABC.c, prettyException("Connect Error:", e), success: false);
+    });
+  }
+}
+
+class DeviceConnection {
+  late StreamSubscription<BluetoothConnectionState> _connectionStateSubscription;
+  late StreamSubscription<bool> _isConnectingSubscription;
+  late StreamSubscription<bool> _isDisconnectingSubscription;
+  late StreamSubscription<int> _mtuSubscription;
+
+  // https://github.com/boskokg/flutter_blue_plus/blob/master/example/lib/screens/device_screen.dart
+}
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