using System;

using _86BoxManager.API;

using System.Diagnostics;

using System.IO;

using System.Runtime.InteropServices;

using System.Text;

using Mono.Unix.Native;

#pragma warning disable CA1416

namespace _86BoxManager.Unix

{

public sealed class UnixLoop : IMessageLoop, IMessageSender, IDisposable

{

private readonly IMessageReceiver _callback;

private readonly UnixExecutor _executor;

private readonly PosixSignalRegistration _posix;

public UnixLoop(IMessageReceiver callback, UnixExecutor executor)

{

_callback = callback;

_executor = executor;

_posix = PosixSignalRegistration.Create(PosixSignal.SIGCONT, OnPosixStop);

}

public void Dispose()

{

_posix.Dispose();

}

~UnixLoop()

{

Dispose();

}

private void SendCommand(IVm vm, string message)

{

var vmName = vm.Name;

var client = _executor.GetClient(vmName);

if (client == null)

return;

var text = message + "\n";

var block = Encoding.UTF8.GetBytes(text);

client.Send(block);

}

public void DoVmRequestStop(IVm vm) => SendCommand(vm, "shutdown");

public void DoVmForceStop(IVm vm) => SendCommand(vm, "shutdownnoprompt");

public void DoVmPause(IVm vm) => SendCommand(vm, "pause");

public void DoVmResume(IVm vm) => DoVmPause(vm);

public void DoVmCtrlAltDel(IVm vm) => SendCommand(vm, "cad");

public void DoVmHardReset(IVm vm) => SendCommand(vm, "reset");

public void DoVmConfigure(IVm vm) => SendCommand(vm, "showsettings");

public IntPtr GetHandle() => new(Environment.ProcessId);

private void OnPosixStop(PosixSignalContext obj)

{

obj.Cancel = true;

var proc = Process.GetCurrentProcess();

var pid = Environment.ProcessId;

var fileMsg = GetMsgFileName(proc, pid);

if (!File.Exists(fileMsg))

return;

var contents = File.ReadAllText(fileMsg, Encoding.UTF8);

File.Delete(fileMsg);

var vmName = contents.Trim();

_callback.OnManagerStartVm(vmName);

}

public void DoManagerStartVm(IntPtr hWnd, string vmName)

{

var pid = hWnd.ToInt32();

var proc = Process.GetProcessById(pid);

var fileMsg = GetMsgFileName(proc, pid);

var contents = string.Empty + vmName;

File.WriteAllText(fileMsg, contents, Encoding.UTF8);

Syscall.kill(pid, Signum.SIGCONT);

}

private static string GetMsgFileName(Process proc, int pid)

{

var mod = proc.MainModule!;

var fileName = mod.FileName;

var fileDir = Path.GetDirectoryName(fileName)!;

var fileMsg = Path.Combine(fileDir, $"p_{pid}.tmp");

return fileMsg;

}

}

}