using System.Net.Sockets;
using Microsoft.Extensions.Logging;
using Microsoft.Extensions.Options;
using Supercell.GUT.Server.Network.Options;

namespace Supercell.GUT.Server.Network.Tcp;
internal class TcpGateway : IServerGateway
{
    private const int TcpBacklog = 100;

    private readonly ILogger _logger;
    private readonly IOptions<GatewayOptions> _options;
    private readonly IGatewayEventListener _listener;
    private readonly Socket _socket;

    private CancellationTokenSource? _listenCancellation;
    private Task? _listenTask;

    public TcpGateway(IOptions<GatewayOptions> options, ILogger<TcpGateway> logger, IGatewayEventListener listener)
    {
        _logger = logger;
        _options = options;
        _listener = listener;
        _socket = new(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
    }

    public void Start()
    {
        _socket.Bind(_options.Value.ListenEndPoint);
        _socket.Listen(TcpBacklog);

        _listenCancellation = new();
        _listenTask = RunAsync(_listenCancellation.Token);

        _logger.LogInformation("Gateway is listening at {ipEndPoint}", _options.Value.ListenEndPoint);
    }

    private async Task RunAsync(CancellationToken cancellationToken)
    {
        while (!cancellationToken.IsCancellationRequested)
        {
            Socket? socket = await _socket.AcceptSocketAsync(cancellationToken);
            if (socket == null) break;

            _listener.OnConnect(new TcpSocketEntity(socket));
        }
    }

    public async Task ShutdownAsync()
    {
        if (_listenCancellation != null)
        {
            await _listenCancellation.CancelAsync();
            await _listenTask!;
        }

        _socket.Close();
    }
}