using Net.Pkcs11Interop.Common;
using Net.Pkcs11Interop.HighLevelAPI;
using System;
using System.Threading;
using System.Threading.Tasks;

namespace StellaOps.Cryptography.Kms;

internal sealed partial class Pkcs11InteropFacade
{
    #pragma warning disable CS1998
    private async Task<SessionContext> OpenSessionAsync(CancellationToken cancellationToken)
    {
        cancellationToken.ThrowIfCancellationRequested();
        var session = _slot.OpenSession(SessionType.ReadOnly);

        var loggedIn = false;

        try
        {
            if (!string.IsNullOrWhiteSpace(_options.UserPin))
            {
                session.Login(CKU.CKU_USER, _options.UserPin);
                loggedIn = true;
            }

            return new SessionContext(session, loggedIn);
        }
        catch
        {
            if (loggedIn)
            {
                try { session.Logout(); } catch { }
            }

            session.Dispose();
            throw;
        }
    }

    private sealed class SessionContext : IDisposable
    {
        private readonly ISession _session;
        private readonly bool _logoutOnDispose;
        private bool _disposed;

        public SessionContext(ISession session, bool logoutOnDispose)
        {
            _session = session ?? throw new ArgumentNullException(nameof(session));
            _logoutOnDispose = logoutOnDispose;
        }

        public ISession Session => _session;

        public void Dispose()
        {
            if (_disposed)
            {
                return;
            }

            if (_logoutOnDispose)
            {
                try
                {
                    _session.Logout();
                }
                catch
                {
                    // ignore logout failures
                }
            }

            _session.Dispose();
            _disposed = true;
        }
    }
}