Xamarin Bluetooth Stack (and Adjustment)

src/SharpBrick.PoweredUp.Mobile/INativeDeviceInfo.cs

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+namespace SharpBrick.PoweredUp.Mobile
+{
+    public interface INativeDeviceInfo
+    {
+        NativeDevice GetNativeDeviceInfo(object device);
+    }
+}

src/SharpBrick.PoweredUp.Mobile/IServiceCollectionExtensionsForXamarin.cs

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+using Microsoft.Extensions.DependencyInjection;
+using Plugin.BLE;
+using Plugin.BLE.Abstractions.Contracts;
+using SharpBrick.PoweredUp.Bluetooth;
+
+namespace SharpBrick.PoweredUp.Mobile
+{
+    public static class IServiceCollectionExtensionsForXamarin
+    {
+        public static IServiceCollection AddXamarinBluetooth(this IServiceCollection self, INativeDeviceInfo deviceInfo)
+            => self
+               .AddSingleton<IBluetoothLE>(CrossBluetoothLE.Current)
+               .AddSingleton<INativeDeviceInfo>(deviceInfo)
+               .AddSingleton<IPoweredUpBluetoothAdapter, XamarinPoweredUpBluetoothAdapter>();
+    }
+}

src/SharpBrick.PoweredUp.Mobile/NativeDevice.cs

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+namespace SharpBrick.PoweredUp.Mobile
+{
+    public class NativeDevice
+    {
+        public string MacAddress { get; set; }
+
+        public ulong MacAddressNumeric { get; set; }
+    }
+}

src/SharpBrick.PoweredUp.Mobile/SharpBrick.PoweredUp.Mobile.csproj

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+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>netstandard2.1</TargetFramework>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="Plugin.BLE" Version="2.1.1" />
+    <PackageReference Include="Prism.Core" Version="8.0.0.1909" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\SharpBrick.PoweredUp\SharpBrick.PoweredUp.csproj" />
+  </ItemGroup>
+
+</Project>

src/SharpBrick.PoweredUp.Mobile/XamarinPoweredUpBluetoothAdapter.cs

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+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading;
+using System.Threading.Tasks;
+using Plugin.BLE.Abstractions;
+using Plugin.BLE.Abstractions.Contracts;
+using Plugin.BLE.Abstractions.EventArgs;
+using SharpBrick.PoweredUp.Bluetooth;
+
+namespace SharpBrick.PoweredUp.Mobile
+{
+    public class XamarinPoweredUpBluetoothAdapter : IPoweredUpBluetoothAdapter
+    {
+        private readonly IAdapter _bluetoothAdapter;
+        private readonly INativeDeviceInfo _deviceInfo;
+        private readonly Dictionary<ulong, IDevice> _discoveredDevices = new Dictionary<ulong, IDevice>();
+
+        public XamarinPoweredUpBluetoothAdapter(IBluetoothLE bluetooth, INativeDeviceInfo deviceInfo)
+        {
+            _bluetoothAdapter = bluetooth.Adapter;
+            _deviceInfo = deviceInfo;
+        }
+
+        public void Discover(Func<PoweredUpBluetoothDeviceInfo, Task> discoveryHandler, CancellationToken cancellationToken = default)
+        {
+            _bluetoothAdapter.ScanMode = ScanMode.Balanced;
+
+            _bluetoothAdapter.DeviceDiscovered += ReceivedHandler;
+
+            cancellationToken.Register(async () =>
+            {
+                await _bluetoothAdapter.StopScanningForDevicesAsync().ConfigureAwait(false);
+                _bluetoothAdapter.DeviceDiscovered -= ReceivedHandler;
+            });
+
+            _bluetoothAdapter.StartScanningForDevicesAsync(new Guid[] { new Guid(PoweredUpBluetoothConstants.LegoHubService) }, DeviceFilter, false).ConfigureAwait(false);
+
+            async void ReceivedHandler(object sender, DeviceEventArgs args)
+            {
+                var info = new PoweredUpBluetoothDeviceInfo();
+
+                var advertisementRecord = args.Device.AdvertisementRecords.FirstOrDefault(x => x.Type == AdvertisementRecordType.ManufacturerSpecificData);
+
+                if (advertisementRecord?.Data?.Length > 0)
+                {
+                    var data = advertisementRecord.Data.ToList();
+                    data.RemoveRange(0, 2);
+                    info.ManufacturerData = data.ToArray();
+                    info.Name = args.Device.Name;
+                    info.BluetoothAddress = _deviceInfo.GetNativeDeviceInfo(args.Device.NativeDevice).MacAddressNumeric;
+
+                    AddInternalDevice(args.Device, info);
+                        await discoveryHandler(info).ConfigureAwait(false);
+                }
+            }
+        }
+
+        private void AddInternalDevice(IDevice device, PoweredUpBluetoothDeviceInfo info)
+        {
+            if (!_discoveredDevices.ContainsKey(info.BluetoothAddress))
+            {
+                _discoveredDevices.Add(info.BluetoothAddress, device);
+            }
+            else
+            {
+                _discoveredDevices[info.BluetoothAddress] = device;
+            }
+        }
+
+        private bool DeviceFilter(IDevice arg)
+        {
+            if (arg == null) return false;
+
+            System.Diagnostics.Debug.WriteLine(arg.Name);
+
+            var manufacturerData = arg.AdvertisementRecords.FirstOrDefault(x => x.Type == AdvertisementRecordType.ManufacturerSpecificData);
+
+            if (manufacturerData?.Data == null || manufacturerData.Data.Length < 8) return false;
+
+            // https://lego.github.io/lego-ble-wireless-protocol-docs/index.html#advertising
+            // Length and Data Type Name seems to be already trimmed away
+            // Manufacturer ID should be 0x0397 but seems in little endian encoding. I found no notice for this in the documentation except in version number encoding
+
+            switch (manufacturerData.Data[3])
+            {
+                case 0x00:
+                    System.Diagnostics.Debug.WriteLine("System: LEGO Wedo 2.0, Device: WeDo Hub");
+                    break;
+                case 0x20:
+                    System.Diagnostics.Debug.WriteLine("System: LEGO Duplo, Device: Duplo Train");
+                    break;
+                case 0x40:
+                    System.Diagnostics.Debug.WriteLine("System: System, Device: Boost Hub");
+                    break;
+                case 0x41:
+                    System.Diagnostics.Debug.WriteLine("System: System, Device: 2 Port Hub");
+                    break;
+                case 0x42:
+                    System.Diagnostics.Debug.WriteLine("System: System, Device: 2 Port Handset");
+                    break;
+                default:
+                    if (manufacturerData.Data[3] >= 96 && manufacturerData.Data[3] < 128)
+                    {
+                        System.Diagnostics.Debug.WriteLine("System: LEGO System, Device: Currently unknown");
+                    }
+                    break;
+            }
+
+            return manufacturerData.Data[0] == 0x97 || manufacturerData.Data[1] == 0x03;
+        }
+
+        public async Task<IPoweredUpBluetoothDevice> GetDeviceAsync(ulong bluetoothAddress)
+        {
+            if (!_discoveredDevices.ContainsKey(bluetoothAddress))
+            {
+                CancellationTokenSource cts = new CancellationTokenSource(10000);
+
+                // trigger scan for 10 seconds
+                Discover((deviceInfo) =>
+                {
+                    return Task.Run(() =>
+                    {
+                        cts.Cancel(false);
+                    });
+
+                }, cts.Token);
+
+                // 60 seconds will be ignored here, because the cancelation will happen after 10 seconds
+                await Task.Delay(60000, cts.Token).ContinueWith(task => { });
+
+                if (!_discoveredDevices.ContainsKey(bluetoothAddress))
+                {
+                    throw new NotSupportedException("Given bt address does not belong to a discovered device");
+                }
+            }
+
+            return new XamarinPoweredUpBluetoothDevice(_discoveredDevices[bluetoothAddress], _bluetoothAdapter);
+        }
+    }
+
+}

src/SharpBrick.PoweredUp.Mobile/XamarinPoweredUpBluetoothCharacteristic.cs

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+using System;
+using System.Threading;
+using System.Threading.Tasks;
+using Plugin.BLE.Abstractions;
+using Plugin.BLE.Abstractions.Contracts;
+using Plugin.BLE.Abstractions.EventArgs;
+using SharpBrick.PoweredUp.Bluetooth;
+
+namespace SharpBrick.PoweredUp.Mobile
+{
+    public class XamarinPoweredUpBluetoothCharacteristic : IPoweredUpBluetoothCharacteristic
+    {
+        private ICharacteristic _characteristic;
+
+        public Guid Uuid => _characteristic.Id;
+
+        public XamarinPoweredUpBluetoothCharacteristic(ICharacteristic characteristic)
+        {
+            this._characteristic = characteristic;
+        }
+
+        public async Task<bool> NotifyValueChangeAsync(Func<byte[], Task> notificationHandler)
+        {
+            if (notificationHandler is null)
+            {
+                throw new ArgumentNullException(nameof(notificationHandler));
+            }
+
+            _characteristic.ValueUpdated += ValueUpdatedHandler;
+
+            void ValueUpdatedHandler(object sender, CharacteristicUpdatedEventArgs e)
+            {
+                notificationHandler(e.Characteristic.Value);
+            }
+
+            await _characteristic.StartUpdatesAsync();
+
+            return true;
+        }
+
+        public async Task<bool> WriteValueAsync(byte[] data)
+        {
+            if (data is null)
+            {
+                throw new ArgumentNullException(nameof(data));
+            }
+
+            return await _characteristic.WriteAsync(data);
+        }
+    }
+}

src/SharpBrick.PoweredUp.Mobile/XamarinPoweredUpBluetoothDevice.cs

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+using System;
+using System.Linq;
+using System.Threading.Tasks;
+using Plugin.BLE.Abstractions;
+using Plugin.BLE.Abstractions.Contracts;
+using SharpBrick.PoweredUp.Bluetooth;
+
+namespace SharpBrick.PoweredUp.Mobile
+{
+    public class XamarinPoweredUpBluetoothDevice : IPoweredUpBluetoothDevice
+    {
+        private IDevice _device;
+        private IAdapter _adapter;
+
+        public string Name => this._device.Name;
+
+        public XamarinPoweredUpBluetoothDevice(IDevice device, IAdapter bluetoothAdapter)
+        {
+            this._device = device;
+            this._adapter = bluetoothAdapter;
+        }
+
+        #region IDisposible
+
+        ~XamarinPoweredUpBluetoothDevice() => Dispose(false);
+
+        public void Dispose() { Dispose(true); GC.SuppressFinalize(this); }
+
+        protected virtual void Dispose(bool disposing)
+        {
+            _device?.Dispose();
+            _device = null;
+            _adapter = null;
+        }
+
+        #endregion
+
+        public async Task<IPoweredUpBluetoothService> GetServiceAsync(Guid serviceId)
+        {
+            await _adapter.ConnectToDeviceAsync(_device, new ConnectParameters(true, true)).ConfigureAwait(false);
+
+            if (!_adapter.ConnectedDevices.Contains(_device)) return null;
+
+            var service = await _device.GetServiceAsync(serviceId).ConfigureAwait(false);
+
+            return new XamarinPoweredUpBluetoothService(service);
+        }
+    }
+}

src/SharpBrick.PoweredUp.Mobile/XamarinPoweredUpBluetoothService.cs

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+using System;
+using System.Threading.Tasks;
+using Plugin.BLE.Abstractions.Contracts;
+using SharpBrick.PoweredUp.Bluetooth;
+
+namespace SharpBrick.PoweredUp.Mobile
+{
+    public class XamarinPoweredUpBluetoothService : IPoweredUpBluetoothService
+    {
+        private IService _service;
+
+        public Guid Uuid => _service.Id;
+
+        public XamarinPoweredUpBluetoothService(IService service)
+        {
+            _service = service ?? throw new ArgumentNullException(nameof(service));
+        }
+
+        #region IDisposable
+
+        ~XamarinPoweredUpBluetoothService() => Dispose(false);
+
+        public void Dispose() { Dispose(true); GC.SuppressFinalize(this); }
+
+        protected virtual void Dispose(bool disposing)
+        {
+            _service.Dispose();
+            _service = null;
+        }
+
+        #endregion
+
+        public async Task<IPoweredUpBluetoothCharacteristic> GetCharacteristicAsync(Guid guid)
+        {
+            var characteristic = await _service.GetCharacteristicAsync(guid);
+
+            if (characteristic == null) return null;
+
+            // await characteristic.StartUpdatesAsync();
+            return new XamarinPoweredUpBluetoothCharacteristic(characteristic);
+
+        }
+    }
+}

src/SharpBrick.PoweredUp/CompilerService.cs

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+namespace System.Runtime.CompilerServices
+{
+#if NETSTANDARD2_1
+    /// <summary>
+    /// Dummy compilerServices which is only included in .NET5 (upwards). To be compatible with .NetStandard 2.1 a dummy is required.
+    /// <see href="https://developercommunity.visualstudio.com/t/error-cs0518-predefined-type-systemruntimecompiler/1244809" />
+    /// </summary>
+    internal static class IsExternalInit { }
+#endif
+}

src/SharpBrick.PoweredUp/SharpBrick.PoweredUp.csproj

@@ -1,7 +1,8 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFramework>net5.0</TargetFramework>
+    <TargetFrameworks>netstandard2.1;net5.0</TargetFrameworks>
+    <LangVersion>9.0</LangVersion>
   </PropertyGroup>
 
   <ItemGroup>