CatLink/Relay/ActiveClient.cs

using System.Net.Sockets;
using System.Text;
using CatLink.Models;
using Microsoft.Extensions.Logging;

namespace CatLink.Relay
{
    public class ActiveClient
    {
        private readonly ILogger<ActiveClient> _logger;
        private readonly Socket _socket;
        private readonly StreamReader _reader;
        private readonly StreamWriter _writer;
        private readonly object _writeLock = new();
        private readonly Thread _thread;
        private readonly Action<ActiveClient, Msg> _messageHandler;
        private readonly Action<ActiveClient> _disconnectHandler;

        public string ClientKey { get; }
        public uint StubIp { get; }
        public Dictionary<int, uint> TcpStreams { get; } = new();
        public HashSet<int> PendingStreams { get; } = new();
        public long LastHeartbeat { get; set; }

        public ActiveClient(
            string clientKey,
            uint stubIp,
            Socket socket,
            Action<ActiveClient, Msg> messageHandler,
            Action<ActiveClient> disconnectHandler,
            ILogger<ActiveClient> logger)
        {
            ClientKey = clientKey;
            StubIp = stubIp;
            _socket = socket;
            _messageHandler = messageHandler;
            _disconnectHandler = disconnectHandler;
            _logger = logger;

            var stream = new NetworkStream(socket);
            _reader = new StreamReader(stream, Encoding.UTF8);
            _writer = new StreamWriter(stream, Encoding.UTF8) { AutoFlush = true };

            LastHeartbeat = DateTimeOffset.UtcNow.ToUnixTimeMilliseconds();

            _thread = new Thread(HandleMessages)
            {
                IsBackground = true
            };
            _thread.Start();
        }

        private void HandleMessages()
        {
            try
            {
                while (_socket.Connected)
                {
                    var line = _reader.ReadLine();
                    if (line == null) break;

                    var msg = Msg.FromString(line);
                    _messageHandler(this, msg);
                }
            }
            catch (Exception ex)
            {
                _logger.LogError(ex, "Error handling messages for client {ClientKey}", ClientKey);
            }
            finally
            {
                _disconnectHandler(this);
            }
        }

        public void Send(Msg msg)
        {
            lock (_writeLock)
            {
                try
                {
                    _writer.WriteLine(msg.ToString());
                }
                catch (Exception ex)
                {
                    _logger.LogError(ex, "Error sending message to client {ClientKey}", ClientKey);
                    Disconnect();
                }
            }
        }

        public void Disconnect()
        {
            try
            {
                _socket.Close();
                _reader.Dispose();
                _writer.Dispose();
            }
            catch (Exception ex)
            {
                _logger.LogError(ex, "Error disconnecting client {ClientKey}", ClientKey);
            }
        }
    }
}