MauMau-Server/Controllers/WebSocketsController.cs

using System.Net.WebSockets;
using System.Text;
using MauMau_Server.Websockets;
using Microsoft.AspNetCore.Mvc;

namespace MauMau_Server.Controllers;

[ApiController]
[Route("[controller]")]
public class WebSocketsController : ControllerBase
{
    private readonly ILogger<WebSocketsController> _logger;
    private readonly IWebsocketManager _websocketManager;
    private string _id = string.Empty;

    public WebSocketsController(ILogger<WebSocketsController> logger, IWebsocketManager websocketManager)
    {
        _logger = logger;
        _websocketManager = websocketManager;
    }

    [HttpGet("/ws")]
    public async Task Get()
    {
        if (HttpContext.WebSockets.IsWebSocketRequest)
        {
            using var webSocket = await HttpContext.WebSockets.AcceptWebSocketAsync();
            _id = _websocketManager.AddConnection(webSocket);
            _logger.Log(LogLevel.Information, $"WebSocket connection {_id} established");
            await Echo(webSocket);
        }
        else
        {
            HttpContext.Response.StatusCode = 400;
        }
    }
        
    private async Task Echo(WebSocket webSocket)
    {
        var buffer = EmptyBuffer();
        var result = await ReceiveAsync(webSocket, buffer);

        while (!result.CloseStatus.HasValue)
        {
            var message = Encoding.UTF8.GetString(buffer);
            BroadcastAsync(message);

            buffer = EmptyBuffer();
            result = await ReceiveAsync(webSocket, buffer);
        }
        await webSocket.CloseAsync(result.CloseStatus.Value, result.CloseStatusDescription, CancellationToken.None);
        _websocketManager.RemoveConnection(_id);
        _logger.Log(LogLevel.Information, $"WebSocket connection {_id} closed");
    }
    
    private async Task<WebSocketReceiveResult?> ReceiveAsync(WebSocket webSocket, byte[] buffer)
    {
        var arraySegment = new ArraySegment<byte>(buffer);
        var result = await webSocket.ReceiveAsync(arraySegment, CancellationToken.None);
        _logger.Log(LogLevel.Information, $"Message received from Client {_id}");
        return result;
    }
    
    private void BroadcastAsync(string message)
    {
        var bytes = Encoding.Default.GetBytes($"{_id}: {message}");
        var arraySegment = new ArraySegment<byte>(bytes);
        foreach (var (id, socket) in _websocketManager.GetAllConnections())
        {
            socket.SendAsync(arraySegment, WebSocketMessageType.Text, true, CancellationToken.None);
            _logger.Log(LogLevel.Information, $"Message from Client {_id} sent to Client {id}");
        }
    }
    
    private static byte[] EmptyBuffer()
    {
        return new byte[4096];
    }
}