FPGA_WebLab/server/src/Hubs/DigitalTubesHub.cs

using Microsoft.AspNetCore.Authorization;
using System.Security.Claims;
using Microsoft.AspNetCore.SignalR;
using Microsoft.AspNetCore.Cors;
using TypedSignalR.Client;
using Tapper;
using DotNext;
using Peripherals.SevenDigitalTubesClient;
using System.Collections.Concurrent;

#pragma warning disable 1998

namespace server.Hubs;

[Hub]
public interface IDigitalTubesHub
{
    Task<bool> StartScan();
    Task<bool> StopScan();
    Task<bool> SetFrequency(int frequency);
    Task<DigitalTubeTaskStatus?> GetStatus();
}

[Receiver]
public interface IDigitalTubesReceiver
{
    Task OnReceive(byte[] data);
}

[TranspilationSource]
public class DigitalTubeTaskStatus
{
    public int Frequency { get; set; } = 100;
    public bool IsRunning { get; set; } = false;

    public DigitalTubeTaskStatus(ScanTaskInfo info)
    {
        Frequency = info.Frequency;
        IsRunning = info.IsRunning;
    }
}

public class ScanTaskInfo
{
    public string BoardID { get; set; }
    public string ClientID { get; set; }
    public Task? ScanTask { get; set; }
    public SevenDigitalTubesCtrl TubeClient { get; set; }
    public CancellationTokenSource CTS { get; set; } = new();
    public int Frequency { get; set; } = 100;
    public bool IsRunning { get; set; } = false;

    public ScanTaskInfo(
        string boardID, string clientID, SevenDigitalTubesCtrl client)
    {
        BoardID = boardID;
        ClientID = clientID;
        TubeClient = client;
    }
}

[Authorize]
[EnableCors("SignalR")]
public class DigitalTubesHub : Hub<IDigitalTubesReceiver>, IDigitalTubesHub
{
    private static NLog.Logger logger = NLog.LogManager.GetCurrentClassLogger();
    private readonly IHubContext<DigitalTubesHub, IDigitalTubesReceiver> _hubContext;
    private readonly Database.UserManager _userManager = new();

    private ConcurrentDictionary<(string, string), ScanTaskInfo> _scanTasks = new();

    public DigitalTubesHub(IHubContext<DigitalTubesHub, IDigitalTubesReceiver> hubContext)
    {
        _hubContext = hubContext;
    }

    private Optional<Database.Board> TryGetBoard()
    {
        var userName = Context.User?.FindFirstValue(ClaimTypes.Name);
        if (string.IsNullOrEmpty(userName))
        {
            logger.Error("User name is null or empty");
            return null;
        }

        var userRet = _userManager.GetUserByName(userName);
        if (!userRet.IsSuccessful || !userRet.Value.HasValue)
        {
            logger.Error($"User '{userName}' not found");
            return null;
        }
        var user = userRet.Value.Value;

        var boardRet = _userManager.GetBoardByID(user.BoardID);
        if (!boardRet.IsSuccessful || !boardRet.Value.HasValue)
        {
            logger.Error($"Board not found");
            return null;
        }
        return boardRet.Value.Value;
    }

    private Task ScanAllTubes(ScanTaskInfo scanInfo)
    {
        var token = scanInfo.CTS.Token;
        return Task.Run(async () =>
        {
            var cntError = 0;
            while (!token.IsCancellationRequested)
            {
                var beginTime = DateTime.Now;
                var waitTime = TimeSpan.FromMilliseconds(1000 / scanInfo.Frequency);

                var dataRet = await scanInfo.TubeClient.ScanAllTubes();
                if (!dataRet.IsSuccessful)
                {
                    logger.Error($"Failed to scan tubes: {dataRet.Error}");
                    cntError++;
                    if (cntError > 3)
                    {
                        logger.Error($"Too many errors, stopping scan");
                        break;
                    }
                }
                await _hubContext.Clients.Client(scanInfo.ClientID).OnReceive(dataRet.Value);

                var processTime = DateTime.Now - beginTime;
                if (processTime < waitTime)
                {
                    await Task.Delay(waitTime - processTime, token);
                }
            }
            scanInfo.IsRunning = false;
        }, token)
        .ContinueWith((task) =>
        {
            if (task.IsFaulted)
            {
                logger.Error(
                    $"Digital tubes scan operation failesj for board {task.Exception}");
            }
            else if (task.IsCanceled)
            {
                logger.Info(
                    $"Digital tubes scan operation cancelled for board {scanInfo.BoardID}");
            }
            else
            {
                logger.Info(
                    $"Digital tubes scan completed successfully for board {scanInfo.BoardID}");
            }
        });
    }

    public async Task<bool> StartScan()
    {
        try
        {
            var board = TryGetBoard().OrThrow(() => new Exception("Board not found"));
            var key = (board.ID.ToString(), Context.ConnectionId);

            if (_scanTasks.TryGetValue(key, out var existing) && existing.IsRunning)
                return true;

            var cts = new CancellationTokenSource();
            var scanTaskInfo = new ScanTaskInfo(
                board.ID.ToString(), Context.ConnectionId,
                new SevenDigitalTubesCtrl(board.IpAddr, board.Port, 0)
            );
            scanTaskInfo.ScanTask = ScanAllTubes(scanTaskInfo);

            _scanTasks[key] = scanTaskInfo;
            return true;
        }
        catch (Exception ex)
        {
            logger.Error(ex, "Failed to start scan");
            return false;
        }
    }

    public async Task<bool> StopScan()
    {
        try
        {
            var board = TryGetBoard().OrThrow(() => new Exception("Board not found"));
            var key = (board.ID.ToString(), Context.ConnectionId);

            if (_scanTasks.TryRemove(key, out var scanInfo))
            {
                scanInfo.IsRunning = false;
                scanInfo.CTS.Cancel();
                if (scanInfo.ScanTask != null)
                    await scanInfo.ScanTask;
                scanInfo.CTS.Dispose();
            }
            return true;
        }
        catch (Exception ex)
        {
            logger.Error(ex, "Failed to stop scan");
            return false;
        }
    }

    public async Task<bool> SetFrequency(int frequency)
    {
        try
        {
            if (frequency < 1 || frequency > 1000)
                return false;

            var board = TryGetBoard().OrThrow(() => new Exception("Board not found"));
            var key = (board.ID.ToString(), Context.ConnectionId);

            if (_scanTasks.TryGetValue(key, out var scanInfo) && scanInfo.IsRunning)
            {
                scanInfo.Frequency = frequency;
                return true;
            }
            else
            {
                logger.Warn($"SetFrequency called but no running scan for board {board.ID} and client {Context.ConnectionId}");
                return false;
            }
        }
        catch (Exception ex)
        {
            logger.Error(ex, "Failed to set frequency");
            return false;
        }
    }

    public async Task<DigitalTubeTaskStatus?> GetStatus()
    {
        try
        {
            var board = TryGetBoard().OrThrow(() => new Exception("Board not found"));
            var key = (board.ID.ToString(), Context.ConnectionId);

            if (_scanTasks.TryGetValue(key, out var scanInfo))
            {
                return new DigitalTubeTaskStatus(scanInfo);
            }
            else
            {
                return null;
            }
        }
        catch (Exception ex)
        {
            logger.Error(ex, "Failed to get status");
            throw new Exception("Failed to get status", ex);
        }
    }

}