using System;
using System.Net;
using NATUPNPLib;

public class UPnPHelper : IDisposable
{
    private UPnPNAT _nat;
    private IStaticPortMappingCollection _mappings;

    public UPnPHelper()
    {
        try
        {
            _nat = new UPnPNAT();
            _mappings = _nat.StaticPortMappingCollection;
        }
        catch (COMException ex)
        {
            throw new InvalidOperationException("UPnP服務(wù)不可用", ex);
        }
    }

    public bool AddPortMapping(int externalPort, int internalPort, string internalIP, ProtocolType protocol, string description = "UPnP Port Forwarding")
    {
        try
        {
            _mappings.Add(externalPort, protocol.ToString().ToUpper(), internalPort, internalIP, true, description);
            return true;
        }
        catch (COMException ex)
        {
            Console.WriteLine($"UPnP映射失敗: {ex.Message}");
            return false;
        }
    }

    public void RemovePortMapping(int externalPort, ProtocolType protocol)
    {
        try
        {
            _mappings.Remove(externalPort, protocol.ToString().ToUpper());
        }
        catch (COMException ex)
        {
            Console.WriteLine($"UPnP解除映射失敗: {ex.Message}");
        }
    }

    public string GetExternalIP()
    {
        using (var client = new WebClient())
        {
            string response = client.DownloadString("http://checkip.dyndns.org/");
            return System.Text.RegularExpressions.Regex.Match(response, @"\b\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}\b").Value;
        }
    }

    public void Dispose()
    {
        _nat?.Dispose();
    }
}

public enum ProtocolType
{
    TCP = 0,
    UDP = 1
}

using System.Net;
using System.Net.Sockets;

public class Server
{
    private Socket _serverSocket;
    private UPnPHelper _upnp;

    public Server(int port)
    {
        _serverSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
        _upnp = new UPnPHelper();
    }

    public void Start()
    {
        try
        {
            // 設(shè)置UPnP映射
            string internalIP = Dns.GetHostEntry(Dns.GetHostName()).AddressList
                .FirstOrDefault(ip => ip.AddressFamily == AddressFamily.InterNetwork)?.ToString();
            
            if (!_upnp.AddPortMapping(8080, 8080, internalIP, ProtocolType.TCP))
            {
                throw new InvalidOperationException("UPnP端口映射失敗");
            }

            string externalIP = _upnp.GetExternalIP();
            Console.WriteLine($"服務(wù)器已啟動 - 外網(wǎng)訪問地址: {externalIP}:8080");

            _serverSocket.Bind(new IPEndPoint(IPAddress.Any, 8080));
            _serverSocket.Listen(10);

            while (true)
            {
                var client = _serverSocket.Accept();
                _ = Task.Run(() => HandleClient(client));
            }
        }
        finally
        {
            _upnp?.Dispose();
        }
    }

    private void HandleClient(Socket client)
    {
        using (var ns = new NetworkStream(client))
        using (var sr = new StreamReader(ns))
        using (var sw = new StreamWriter(ns))
        {
            string msg = sr.ReadLine();
            Console.WriteLine($"收到消息: {msg}");
            sw.WriteLine($"ECHO: {msg}");
            sw.Flush();
        }
    }
}

using System.Net;
using System.Net.Sockets;

public class UPnPClient
{
    private string _externalIP;
    private int _externalPort;

    public void Connect(string serverIP, int serverPort)
    {
        // 通過UPnP獲取外部IP和端口
        using (var client = new WebClient())
        {
            string response = client.DownloadString("http://checkip.dyndns.org/");
            _externalIP = System.Text.RegularExpressions.Regex.Match(response, @"\b\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}\b").Value;
        }

        _externalPort = serverPort;

        // 建立TCP連接
        var socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
        socket.Connect(new IPEndPoint(IPAddress.Parse(_externalIP), _externalPort));

        using (var ns = new NetworkStream(socket))
        using (var sr = new StreamReader(ns))
        using (var sw = new StreamWriter(ns))
        {
            sw.WriteLine("Hello Server");
            sw.Flush();

            string response = sr.ReadLine();
            Console.WriteLine($"服務(wù)器響應(yīng): {response}");
        }
    }
}

class Program
{
    static void Main(string[] args)
    {
        var server = new Server(8080);
        server.Start();
    }
}

class Program
{
    static void Main(string[] args)
    {
        var client = new UPnPClient();
        client.Connect("服務(wù)器公網(wǎng)IP", 8080); // 替換為實(shí)際公網(wǎng)IP
    }
}

// 在UPnPHelper中擴(kuò)展UDP支持
public bool AddUdpPortMapping(int externalPort, int internalPort, string internalIP)
{
    return AddPortMapping(externalPort, internalPort, internalIP, ProtocolType.UDP);
}

// 在客戶端添加重試邏輯
public void ConnectWithRetry(string serverIP, int serverPort, int maxRetries = 3)
{
    int attempt = 0;
    while (attempt < maxRetries)
    {
        try
        {
            Connect(serverIP, serverPort);
            return;
        }
        catch (Exception ex)
        {
            attempt++;
            Console.WriteLine($"連接失敗 ({attempt}/{maxRetries}): {ex.Message}");
            Thread.Sleep(2000);
        }
    }
}

// 添加TLS加密
public void StartSecureServer(int port)
{
    _serverSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
    _serverSocket.Bind(new IPEndPoint(IPAddress.Any, port));
    _serverSocket.Listen(10);

    using (var sslStream = new SslStream(_serverSocket.Accept(), false))
    {
        sslStream.AuthenticateAsServer(GetCertificate());
        // 處理加密通信...
    }
}