MauMau-Server/Room/Room.cs

using System.Collections;
using System.Net.WebSockets;
using System.Text;
using System.Text.Json;
using MauMau_Server.Mau;

namespace MauMau_Server.Websockets;

public class Room
{
    private readonly IRoomManager _roomManager;
    private readonly string _roomId;
    private readonly List<ConnectionInstance> _connections = new();
    private ConnectionInstance _host;
    private readonly Chat _chat;
    private readonly Game _game = new();

    public Room(IRoomManager roomManager, string roomId)
    {
        _roomManager = roomManager;
        _chat = new Chat(this);
        _roomId = roomId;
    }

    public async Task InstantiateConnection(WebSocket socket)
    {
        var connection = AddConnection(socket);
        if (IsEmpty()) _host = connection;
        _game.AddPlayerToGame(connection);
        await HandleConnection(connection.Socket, connection.ConnectionId);
    }

    private async Task HandleConnection(WebSocket webSocket, string connectionId)
    {
        BroadcastGameState();
        var buffer = EmptyBuffer();
        var result = await ReceiveAsync(webSocket, buffer);
        while (!result.CloseStatus.HasValue)
        {
            var slicedBuffer = buffer[0..result.Count];
            var message = JsonSerializer.Deserialize<MessageDTO>(slicedBuffer);
            switch (message.Type)
            {
                case "GAME":
                {
                    var gameInput = JsonSerializer.Deserialize<ActionDTO>(message.Payload);
                    _game.HandleAction(connectionId, gameInput);
                    break;
                }
                case "CHAT":
                {
                    _chat.SendChatMessage(connectionId, message.Payload);
                    break;
                }
            }
            BroadcastGameState();
            buffer = EmptyBuffer();
            result = await ReceiveAsync(webSocket, buffer);
        }

        await webSocket.CloseAsync(result.CloseStatus.Value, result.CloseStatusDescription,
            CancellationToken.None);
        HandleDisconnect(connectionId);
    }

    private ConnectionInstance AddConnection(WebSocket socket)
    {
        var connectionId = Guid.NewGuid().ToString();
        var connection = new ConnectionInstance(connectionId, socket);
        _connections.Add(connection);
        return connection;
    }

    public void RemoveConnection(string socketId)
    {
        _connections.RemoveAll(connection => connection.ConnectionId == socketId);
    }

    private static async Task<WebSocketReceiveResult?> ReceiveAsync(WebSocket webSocket, byte[] buffer)
    {
        var arraySegment = new ArraySegment<byte>(buffer);
        var result = await webSocket.ReceiveAsync(arraySegment, CancellationToken.None);
        return result;
    }

    private void BroadcastGameState()
    {
        foreach (var connection in _connections)
        {
            var gameState = new GameState(_game, connection.ConnectionId);
            var message = new MessageDTO("GAME", JsonSerializer.Serialize(gameState));
            WebsocketManager.SendAsync(connection.Socket, JsonSerializer.Serialize(message));
        }
    }

    private void HandleDisconnect(string socketId)
    {
        RemoveConnection(socketId);
        _game.RemovePlayer(socketId);
        if (IsEmpty())
        {
            _roomManager.RemoveRoom(_roomId);
        }
        else if (socketId == _host.ConnectionId)
        {
            _host = _connections.First();
        }
    }
    
    public List<WebSocket> GetWebsockets()
    {
        return _connections.Select(connection => connection.Socket).ToList();
    }

    private static byte[] EmptyBuffer()
    {
        return new byte[4096];
    }

    public bool IsEmpty()
    {
        return _connections.Count == 0;
    }
}