using System.Diagnostics;

using System.Runtime.InteropServices;

using System.Security.Principal;

using System.Text;

namespace BlinkkShell

{

internal static class ShellHandles

{

public static string ProcessCommand(string commandLine)

{

if (string.IsNullOrWhiteSpace(commandLine))

return "Empty command.";

string[] parts = commandLine.Split(' ', 2, StringSplitOptions.RemoveEmptyEntries);

string command = parts[0].ToLowerInvariant();

string args = parts.Length > 1 ? parts[1] : string.Empty;

return command switch

{

"help" => GetHelpText(),

"this" => GetShellInfo(),

"whoami" => GetWhoAmIInfo(),

"cmdmsg" => ShowConsoleMessage(args),

"msg" => ShowMessageBox(args),

"ping" => "Pong!",

"shelluptime" => $"Shell Uptime: {DateTime.Now - Process.GetCurrentProcess().StartTime}",

"sysinfo" => GetSystemInfo(),

"time" => GetLocalTime(),

"uptime" => $"System Uptime: {TimeSpan.FromMilliseconds(Environment.TickCount64)}",

_ => $"Unknown command: '{command}'. Type 'help' to see the available commands."

};

}

private static string GetHelpText()

{

return """

BlinkkShell commands

====================

help Show this command list.

this Show BlinkkShell server and process details.

sysinfo Show operating system and runtime details.

whoami Show the server account and administrator status.

uptime Show how long the computer has been running.

shelluptime Show how long the BlinkkShell process has been running.

time Show the server's local date and time.

ping Check that the server responds.

cmdmsg <text> Display a message on the server console.

msg <text> Display a message on the server (Windows only).

exit Close this client session.

Commands are case-insensitive.

""";

}

private static string GetLocalTime()

{

return $"Local Date and Time: {DateTime.Now:yyyy-MM-dd HH:mm:ss}";

}

private static string GetShellInfo()

{

Process currentProcess = Process.GetCurrentProcess();

return $"""

BlinkkShell Channel

=================

Version : 1.0.5

Computer : {Environment.MachineName}

Account : {Environment.UserName}

Process ID : {currentProcess.Id}

""";

}

private static string GetSystemInfo()

{

return $"""

System information

==================

{"Computer",-21}: {Environment.MachineName}

{"Operating system",-21}: {RuntimeInformation.OSDescription}

{"OS architecture",-21}: {RuntimeInformation.OSArchitecture}

{"Process architecture",-21}: {RuntimeInformation.ProcessArchitecture}

{"Logical processors",-21}: {Environment.ProcessorCount}

{".NET runtime",-21}: {RuntimeInformation.FrameworkDescription}

""";

}

private static string GetWhoAmIInfo()

{

string username = Environment.UserName;

string domain = Environment.UserDomainName;

if (!OperatingSystem.IsWindows())

return $"Current User: {domain}\\{username}\nAdmin Mode: Unavailable (Windows only)";

using WindowsIdentity identity = WindowsIdentity.GetCurrent();

WindowsPrincipal principal = new WindowsPrincipal(identity);

bool isAdmin = principal.IsInRole(WindowsBuiltInRole.Administrator);

string adminStatus = isAdmin ? "YES (Administrator / Elevated)" : "NO (Standard User)";

return $"Current User: {domain}\\{username}\nAdmin Mode: {adminStatus}";

}

private static string ShowConsoleMessage(string message)

{

if (string.IsNullOrWhiteSpace(message))

return "Usage: consolemsg <message_text>";

Console.WriteLine($"Remote message: {message}");

return "Message displayed on server console.";

}

private static string ShowMessageBox(string message)

{

if (string.IsNullOrWhiteSpace(message))

return "Usage: msg <message_text>";

if (!OperatingSystem.IsWindows())

return "The message command is only available on Windows.";

string encodedMessage = Convert.ToBase64String(Encoding.UTF8.GetBytes(message));

string script = "$message = [Text.Encoding]::UTF8.GetString([Convert]::FromBase64String('" +

encodedMessage +

"')); Add-Type -AssemblyName System.Windows.Forms; " +

"$form = New-Object System.Windows.Forms.Form; " +

"$form.TopMost = $true; " +

"[System.Windows.Forms.MessageBox]::Show($form, $message, 'BlinkkShell Message', [System.Windows.Forms.MessageBoxButtons]::OK, [System.Windows.Forms.MessageBoxIcon]::Information); " +

"$form.Dispose();";

try

{

using Process? process = Process.Start(new ProcessStartInfo

{

FileName = "powershell",

ArgumentList = { "-NoProfile", "-EncodedCommand", Convert.ToBase64String(Encoding.Unicode.GetBytes(script)) },

CreateNoWindow = true,

UseShellExecute = false

});

return process == null ? "Failed to start the message window." : "Message displayed on screen.";

}

catch (Exception exception) when (exception is InvalidOperationException or System.ComponentModel.Win32Exception)

{

return $"Failed to display the message: {exception.Message}";

}

}

}

}