ReboundEmulator/TCPGameServer.cs

using System.Net.Sockets;
using System.Net;
using NotPogo.Core;

namespace NotPogo
{
    public class TCPGameServer(ILogger<TCPGameServer> logger, IConfiguration configuration) : BackgroundService
    {
        private readonly ILogger<TCPGameServer> _logger = logger;
        private readonly IConfiguration _configuration = configuration;

        private int _tcpPort;

        public TcpListener? Listener { get; private set; }

        public static List<TcpClient> Clients { get; } = [];
        public static BowlingGame? SingleplayerBowlingGame;

        protected override async Task ExecuteAsync(CancellationToken stoppingToken)
        {
            _tcpPort = _configuration.GetValue<int>("GameServerPort");
            Listener = new(IPAddress.Any, _tcpPort);
            Listener.Start();
            _logger.LogInformation("Game Server Listening On Port {Port}", _tcpPort);

            while (!stoppingToken.IsCancellationRequested)
            {
                var client = await Listener.AcceptTcpClientAsync(stoppingToken);
                _logger.LogInformation("Client Connected: {RemoteEndPoint}", client.Client.RemoteEndPoint);
                _ = HandleClientAsync(client);
            }
        }

        private async Task HandleClientAsync(TcpClient client)
        {
            using (client)
            await using (var stream = client.GetStream())
            {
                try
                {
                    while (true)
                    {
                        Dictionary<string, string> received;
                        try
                        {
                            received = await TCPProtocol.ReadMessageAsync(stream);
                        }
                        catch (EndOfStreamException) { break; }

                        _logger.LogInformation("Received:");
                        foreach (var kv in received)
                            _logger.LogInformation("    {Key} = {Value}", kv.Key, kv.Value);

                        if (!received.TryGetValue("msg.op", out var op)) continue;

                        if (op == "logn") // Login Request
                        {
                            // we know this is a compatible client now so let's add it to the client list
                            Clients.Add(client);

                            // send logn response chain
                            await SendAsync(stream, ("msg.op", "logn"), ("flags", "65535"), ("time", DateTimeOffset.UtcNow.ToUnixTimeSeconds().ToString()));
                            await SendAsync(stream, ("msg.op", "init"), ("mxpl", "70"), ("plid", "1"), ("mxtb", "70"), ("mxst", "4"), ("cnid", "1623"));
                            await SendAsync(stream, ("msg.op", "load"), ("rmst", "start"));
                            await SendAsync(stream, ("msg.op", "rm.join"), ("scrn", "NotPogoUser"), ("pfid", "1000000000"), ("plid", "1"), ("entl", "ictsebpaulovfFmMrRG"),
                                                    ("snme", "NotPogoUser"), ("priv", "0"), ("aepc", ""), ("acvw", ""), ("agvs", ""), ("alrc", ""));
                            await SendAsync(stream, ("msg.op", "gm.crea"), ("launch", "y"), ("live", "0"), ("port", "0"), ("iali", "86400000"), ("gins", "NotPogoTempRoom"),
                                                    ("dead", "0"), ("iaid", "15000"), ("shut", ""), ("gmid", "0"));
                            await SendAsync(stream, ("msg.op", "load"), ("rmst", "end"));
                            await SendAsync(stream, ("msg.op", "say"), ("chnl", "serv"), ("scrn", "NotPogoUser"), ("type", "stnd"), ("text", 
                                                                                                                                            "Welcome to Not Pogo, the best place for games, fun and friends!"));
                            await SendAsync(stream, ("msg.op", "say"), ("chnl", "serv"), ("scrn", "NotPogoUser"), ("type", "stnd"), ("text", 
                                                                                                                                            "Caution: This emulator is in Alpha Stages. Some things may not work, even with proper game properties."));
                            await SendAsync(stream, ("msg.op", "pl.rm.stte"), ("plid", "1"), ("gmpf", ""), ("glpf", "..."), ("frls", ""));
                            await SendAsync(stream, ("msg.op", "pl.rm.stte"), ("plid", "1"), ("tokb", "9999"));
                            await SendAsync(stream, ("msg.op", "pl.rm.stte"), ("plid", "1"), ("avtr", ""), ("icon", "avatarminighost"));
                            _logger.LogInformation("Sent 'logn' Response Sequence");
                        }
                        else if (op == "gm.join") // Room Join Request
                        {
                            // send gm.join response chain
                            await SendAsync(stream, ("msg.op", "gm.join"), ("plid", "1"), ("snme", "NotPogoUser"), ("gmid", "0"), ("scrn", "NotPogoUser"), ("join", "join"));
                            await SendAsync(stream, ("msg.op", "gm.lnch"), ("gmid", "0"));
                            await SendAsync(stream, ("msg.op", "tokb"), ("tokb", "9999"));
                            await SendAsync(stream, ("msg.op", "tick"), ("scrn", "NotPogoUser"), ("text", "Welcome to Not Pogo!"));
                            await SendAsync(stream, ("msg.op", "cnfg"), ("impd", "40"));
                            await SendAsync(stream, ("msg.op", "ext.pref"), ("pref", ""));
                            _logger.LogInformation("Sent 'gm.join' Response Sequence (Launches Game)");
                        }
                        else if (op == "ext.over")
                        {
                            // because we aren't actually keeping track of anything going on in the games, we can just send the correct placeholders

                            bool isJackpot = (received["gm.won"] == "true") ? true : false;
                            int tokensWon = Random.Shared.Next(0, 999);

                            await SendAsync(stream,
                                ("msg.op", "ext.rslt"),
                                ("tokb", "9999"),
                                ("tokn.won", isJackpot ? "100" : "0"),
                                ("spin.rslt", isJackpot ? "2" : "0"), // we aren't doing anything with the other outcomes so always issue tokens
                                ("spin.tokn", tokensWon.ToString()), // standalone reference implementation
                                ("inst.desc", ""),
                                ("jpot", "0"),
                                ("pzpm", ""),
                                ("bmlt", "1"),
                                ("bspo", "0"),
                                ("xpup", "0")
                            );

                            _logger.LogInformation("Results Sent");
                        } else if (op == "co.redy")
                        {
                            // when client is ready, start game loop
                            SingleplayerBowlingGame ??= new();
                            _ = SingleplayerBowlingGame.StartGameLoop(stream);
                        } else if (op == "co.turn")
                        {
                            // increment score
                            SingleplayerBowlingGame?.RecordThrow(int.Parse(received["pins"]));
                        }
                    }
                } catch (Exception e) { _logger.LogError(e, "Error Handling Client"); }
            }

            Clients.Remove(client);
            _logger.LogInformation("Client Disconnected");
        }

        public static Task SendAsync(NetworkStream stream, params (string key, string value)[] fields)
        {
            var msg = new Dictionary<string, string>();
            foreach (var (key, value) in fields) msg[key] = value;
            return TCPProtocol.WriteMessageAsync(stream, msg);
        }

        static Dictionary<string, int> ParseInlineMap(string raw)
        {
            var result = new Dictionary<string, int>();
            if (string.IsNullOrEmpty(raw)) return result;

            var trimmed = raw.Trim('{', '}');
            foreach(var pair in trimmed.Split(','))
            {
                var kv = pair.Split('=');
                if(kv.Length != 2) continue;
                var key = kv[0].Trim();
                if (int.TryParse(kv[1].Trim(), out int value))
                    result[key] = value;
            }
            return result;
        }

        public override Task StopAsync(CancellationToken cancellationToken)
        {
            if(!cancellationToken.IsCancellationRequested)
            {
                Clients.Clear();
                Listener?.Stop();
                Listener?.Dispose();
            }

            return Task.CompletedTask;
        }
    }
}