#define TRACE
using System;
using System.Diagnostics;
using System.Threading;

namespace ArchestrAServices.Common;

public class ServiceShutdownControl : IDisposable
{
	public delegate void ShutdownCallback();

	private readonly ShutdownCallback m_Callback;

	private bool disposed;

	public ServiceShutdownControl(ShutdownCallback callback = null)
	{
		m_Callback = callback;
	}

	~ServiceShutdownControl()
	{
		Dispose(disposing: false);
	}

	public static void SignalShutdown(Process watchedServiceProcess, string serviceInstanceName)
	{
		SvcTrace.DiagDiagnostics.TraceEvent(TraceEventType.Information, 0, "ServiceShutdownControl: SignalShutdown called");
		try
		{
			if (!string.IsNullOrWhiteSpace(serviceInstanceName))
			{
				EventWaitHandle eventWaitHandle = EventWaitHandle.OpenExisting(serviceInstanceName);
				SvcTrace.DiagDiagnostics.TraceEvent(TraceEventType.Information, 0, $"ServiceShutdownControl: Setting shutdown signal for process {serviceInstanceName}");
				eventWaitHandle.Set();
				SvcTrace.DiagDiagnostics.TraceEvent(TraceEventType.Information, 0, $"ServiceShutdownControl: Closing the process {serviceInstanceName}");
				watchedServiceProcess?.WaitForExit(15000);
			}
			else
			{
				SvcTrace.DiagDiagnostics.TraceEvent(TraceEventType.Warning, 0, "ServiceShutdownControl: Process name cannot be null/empty.");
			}
		}
		catch (WaitHandleCannotBeOpenedException)
		{
			SvcTrace.DiagException.TraceEvent(TraceEventType.Error, 0, "ServiceShutdownControl: Named event does not exist.");
		}
		catch (UnauthorizedAccessException ex2)
		{
			SvcTrace.DiagException.TraceEvent(TraceEventType.Error, 0, $"ServiceShutdownControl: Unauthorized access: {ex2.Message}");
		}
		catch (Exception ex3)
		{
			SvcTrace.DiagException.TraceEvent(TraceEventType.Error, 0, $"ServiceShutdownControl: Exception in SignalShutdown: {ex3.Message}");
		}
		if (watchedServiceProcess != null && !watchedServiceProcess.HasExited)
		{
			try
			{
				watchedServiceProcess.Kill();
			}
			catch (Exception)
			{
			}
		}
		SvcTrace.DiagDiagnostics.TraceEvent(TraceEventType.Information, 0, "ServiceShutdownControl: SignalShutdown exited");
	}

	public void WaitForShutdown(string serviceInstanceName)
	{
		SvcTrace.DiagDiagnostics.TraceEvent(TraceEventType.Information, 0, "ServiceShutdownControl: WaitForShutdown called.");
		try
		{
			if (!string.IsNullOrEmpty(serviceInstanceName))
			{
				EventWaitHandle eventWaitHandle = new EventWaitHandle(initialState: false, EventResetMode.AutoReset, serviceInstanceName);
				SvcTrace.DiagDiagnostics.TraceEvent(TraceEventType.Information, 0, $"ServiceShutdownControl: Starting wait for shutdown signal for process {serviceInstanceName}");
				eventWaitHandle.WaitOne();
				SvcTrace.DiagDiagnostics.TraceEvent(TraceEventType.Information, 0, $"ServiceShutdownControl: Received shutdown signal, stopping process {serviceInstanceName}");
			}
			else
			{
				SvcTrace.DiagDiagnostics.TraceEvent(TraceEventType.Warning, 0, "ServiceShutdownControl: Process name cannot be null/empty.");
			}
		}
		catch (WaitHandleCannotBeOpenedException)
		{
			SvcTrace.DiagException.TraceEvent(TraceEventType.Error, 0, $"ServiceShutdownControl: Named event does not exist for process {serviceInstanceName}");
		}
		catch (UnauthorizedAccessException ex2)
		{
			SvcTrace.DiagException.TraceEvent(TraceEventType.Error, 0, $"ServiceShutdownControl: Unauthorized access: {ex2.Message}");
		}
		catch (Exception ex3)
		{
			SvcTrace.DiagException.TraceEvent(TraceEventType.Error, 0, $"ServiceShutdownControl: Exception in WaitForShutdown: {ex3.Message}");
		}
		try
		{
			if (m_Callback != null)
			{
				SvcTrace.DiagDiagnostics.TraceEvent(TraceEventType.Information, 0, "ServiceShutdownControl: Calling user-supplied shutdown callback");
				m_Callback();
				SvcTrace.DiagDiagnostics.TraceEvent(TraceEventType.Information, 0, "ServiceShutdownControl: Returned from user-supplied shutdown callback");
			}
		}
		catch (Exception ex4)
		{
			SvcTrace.DiagException.TraceEvent(TraceEventType.Error, 0, $"ServiceShutdownControl: Exception calling user-supplied callback: {ex4.Message}");
		}
		SvcTrace.DiagDiagnostics.TraceEvent(TraceEventType.Information, 0, "ServiceShutdownControl: WaitForShutdown exited.");
	}

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

	protected virtual void Dispose(bool disposing)
	{
		if (!disposed)
		{
			SvcTrace.DiagDiagnostics.TraceEvent(TraceEventType.Stop, 0, "ServiceShutdownControl disposing");
			disposed = true;
		}
	}
}