AVSKS

using System;
using System.Net;
using System.Net.Sockets;
using System.Text;
using System.Threading;
using System.IO;
using System.Collections.Generic;

namespace server
{
    class Program
    {
        static TcpListener listener = null;
        static Dictionary<string, string> credentials;
        static Dictionary<string, TcpClient> clients = new Dictionary<string, TcpClient>();
        static Dictionary<string, TcpClient> authclients = new Dictionary<string, TcpClient>();

        static void Main(string[] args)
        {
            string filePath = "clients.txt";
            credentials = ReadCredentialsFromFile(filePath);

            listener = new TcpListener(IPAddress.Any, 8000);
            listener.Start();
            Console.WriteLine("Сервер запущен. Ожидание подключений...");

            while (true)
            {
                TcpClient client = listener.AcceptTcpClient();
                Thread clientThread = new Thread(() => HandleClient(client));
                clientThread.Start();
            }
        }

        static Dictionary<string, string> ReadCredentialsFromFile(string filePath)
        {
            Dictionary<string, string> credentials = new Dictionary<string, string>();
            try
            {
                string[] lines = File.ReadAllLines(filePath);
                foreach (string line in lines)
                {
                    string[] tokens = line.Split(' ');
                    if (tokens.Length == 2)
                    {
                        string username = tokens[0];
                        string password = tokens[1];
                        credentials[username] = password;
                    }
                }
            }
            catch (Exception ex)
            {
                Console.WriteLine($"Ошибка при чтении файла: {ex.Message}");
            }
            return credentials;
        }

        static void HandleClient(TcpClient client)
        {
            NetworkStream stream = client.GetStream();
            byte[] buffer = new byte[1024];
            int bytesRead;

            bool isAuthenticated = false;

            while (true)
            {
                bytesRead = 0;
                try
                {
                    bytesRead = stream.Read(buffer, 0, buffer.Length);
                }
                catch
                {
                    break;
                }
                if (bytesRead == 0)
                {
                    break;
                }

                string message = Encoding.UTF8.GetString(buffer, 0, bytesRead);

                if (!isAuthenticated && message.StartsWith("AUTH"))
                {
                    string[] authData = message.Split(' ');
                    if (authData.Length == 3)
                    {
                        string username = authData[1];
                        string password = authData[2];
                        if (credentials.ContainsKey(username) && credentials[username] == password)
                        {
                            if (authclients.ContainsKey(username))
                            {
                                SendMessage(client, "Ошибка: клиент с даннымм логином уже подключен");
                                Console.WriteLine($"{username} уже подключен");
                                client.Close();
                            }
                            else
                            {
                                authclients[username] = client;
                                clients[username] = client;
                                SendMessage(client, "AUTH_SUCCES");
                                Console.WriteLine($"{username} успешно аутентифицирован");
                                isAuthenticated = true;
                            }
                        }
                        else
                        {
                            SendMessage(client, $"Ошибка аутентификации {username}");
                            Console.WriteLine($"{username} ошибка аутентификации");
                            client.Close();
                        }
                    }
                }

                Console.WriteLine($"Получено сообщение от клиента {message}");
                foreach (var kvp in authclients)
                {
                    if (kvp.Value != client && kvp.Value.Connected)
                    {
                        if (!message.StartsWith("AUTH"))
                        {
                            SendMessage(kvp.Value, message);
                        }
                    }
                }
            }
            Console.WriteLine("Клиент отключился");
            client.Close();
        }

        static void SendMessage(TcpClient client, string message)
        {
            NetworkStream stream = client.GetStream();
            byte[] buffer = Encoding.UTF8.GetBytes(message);
            stream.Write(buffer, 0, buffer.Length);
        }
    }
}