sharee.bike-App/LockIt.BLE/Services/BluetoothLock/BLE/LockItByGuidService.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;
using LockIt.BusinessLogic.Services.BluetoothLock;
using Plugin.BLE;
using Plugin.BLE.Abstractions;
using Plugin.BLE.Abstractions.Contracts;
using Serilog;
using ShareeBike.Model.Connector;
using ShareeBike.Model.Device;
using ShareeBike.Services.BluetoothLock.Exception;
using ShareeBike.Services.BluetoothLock.Tdo;
using Xamarin.Essentials;

namespace ShareeBike.Services.BluetoothLock.BLE
{
	public class LockItByGuidService : LockItServiceBase, ILocksService
	{
		/// <summary> Constructs a LockItByGuidService object.</summary>
		/// <param name="cipher">Encrpyting/ decrypting object.</param>
		public LockItByGuidService(ICipher cipher) : base(cipher)
		{
		}

		/// <summary> Checks for locks which have not yet been discoverted and connects them. </summary>
		/// <remarks> Consists of a bluetooth connect plus invocation of an authentication sequence. </remarks>
		/// <param name="locksInfo">Locks to reconnect.</param>
		/// <param name="connectTimeout">Timeout for connect operation of a single lock.</param>
		protected override async Task<IEnumerable<ILockService>> CheckConnectMissing(IEnumerable<LockInfoAuthTdo> locksInfo, TimeSpan connectTimeout)
		{
			if (DeviceInfo.Platform != DevicePlatform.Unknown && MainThread.IsMainThread == false)
			{
				throw new System.Exception("Can not connect to locks by guid. Platform must not be unknown and bluetooth code must be run on main thread.");
			}

			// Get list of target locks without invalid entries.
			var validLocksInfo = locksInfo
				.Where(x => x.IsGuidValid)
				.Where(x => x.K_seed.Length > 0 && x.K_u.Length > 0)
				.ToList();

			var locksList = new List<ILockService>();

			// Connect to 
			foreach (var lockInfo in validLocksInfo)
			{
				if (DeviceList.Any(x => x.Name.GetBluetoothLockId() == lockInfo.Id || x.Guid == lockInfo.Guid))
				{
					// Device is already connected.
					continue;
				}

				// Connect to device and authenticate.
				ILockService lockIt = null;
				try
				{
					lockIt = await ConnectByGuid(lockInfo, connectTimeout);
				}
				catch (System.Exception exception)
				{
					// Member is called for background update of missing devices. 
					// Do not display any error messages.
					Log.ForContext<LockItByGuidService>().Error($"Authentication failed. {exception.Message}");
					continue;
				}
				if (lockIt == null)
				{
					continue;
				}

				locksList.Add(lockIt);
			}

			return locksList;
		}

		/// <summary> Connects to lock.</summary>
		/// <remarks> Consists of a bluetooth connect plus invocation of an authentication sequence. </remarks>
		/// <param name="authInfo"> Info required to connect to lock.</param>
		/// <param name="connectTimeout">Timeout for connect operation.</param>
		public async Task<LockInfoTdo> ConnectAsync(LockInfoAuthTdo authInfo, TimeSpan connectTimeout)
		{
			if (DeviceInfo.Platform != DevicePlatform.Unknown && MainThread.IsMainThread == false)
			{
				throw new System.Exception("Can not connect to lock by guid. Platform must not be unknown and bluetooth code must be run on main thread.");
			}

			// Connect to device and authenticate.
			var lockIt = await ConnectByGuid(authInfo, connectTimeout);

			if (lockIt == null)
			{
				return new LockInfoTdo.Builder { Id = authInfo.Id, Guid = authInfo.Guid, State = null }.Build();
			}

			DeviceList.Add(lockIt);

			return await lockIt.GetLockStateAsync();
		}

		/// <summary> Connects to lock.</summary>
		/// <remarks> Consists of a bluetooth connect plus invocation of an authentication sequence. </remarks>
		/// <param name="authInfo"> Info required to connect to lock.</param>
		/// <param name="connectTimeout">Timeout for connect operation.</param>
		private async Task<ILockService> ConnectByGuid(LockInfoAuthTdo authInfo, TimeSpan connectTimeout)
		{
			if (authInfo.Guid == TextToLockItTypeHelper.INVALIDLOCKGUID)
			{
				Log.ForContext<LockItByGuidService>().Error($"Can not connect to lock {authInfo.Id}. Guid is unknown.");
				throw new GuidUnknownException();
			}

			var lockIt = DeviceList.FirstOrDefault(x => x.Name.GetBluetoothLockId() == authInfo.Id || x.Guid == authInfo.Guid);
			if (lockIt != null && lockIt.GetDeviceState() == DeviceState.Connected)
			{
				// Device is already connected.
				return lockIt;
			}

			var adapter = CrossBluetoothLE.Current.Adapter;
			Log.ForContext<LockItByGuidService>().Debug($"Request connect to device {authInfo.Id}.");

			if (LockItByGuidServiceHelper.DevelGuids.ContainsKey(authInfo.Id) && LockItByGuidServiceHelper.DevelGuids[authInfo.Id] != authInfo.Guid)
				throw new System.Exception($"Invalid Guid {authInfo.Guid} for lock with id {authInfo.Id} detected. Guid should be {LockItByGuidServiceHelper.DevelGuids[authInfo.Id]}.");

			IDevice device;
			var cts = new CancellationTokenSource(connectTimeout);
			// Step 1: Perform bluetooth connect.
			try
			{
				device = await adapter.ConnectToKnownDeviceAsync(
					authInfo.Guid,
					new ConnectParameters(forceBleTransport: true), // Force BLE transport 
					cts.Token);
			}
			catch (System.Exception exception)
			{
				if (exception is TaskCanceledException)
				{
					// A timeout occurred.
					throw new System.Exception($"Can not connect to lock by guid.\r\nTimeout of {connectTimeout.TotalMilliseconds} [ms] elapsed.", exception);
				}

				Log.ForContext<LockItByGuidService>().Error("Bluetooth connect to known device request failed. {Exception}", exception);
				throw new System.Exception($"Can not connect to lock by guid.\r\n{exception.Message}", exception);
			}

			// Step 2: Authenticate.
			lockIt = await LockItEventBased.Authenticate(device, authInfo, CrossBluetoothLE.Current.Adapter, Cipher);

			if (lockIt == null)
			{
				Log.ForContext<LockItByGuidService>().Error("Connect to device failed.");
				return null;
			}

			return lockIt;
		}
	}
}