Demka_kur/Hardik/Date/Timer.cs

using System;
using System.Timers;

namespace Demka_Snova_1.Hardik.Date
{
    public class Otchot
    {
        private Timer _timer;
        private int _sessionDuration = 10;
        private int _warningTime = 5;
        private int _blockTime = 3;
        private DateTime _sessionStartTime;

        public event Action<string> OnWarning;
        public event Action OnSessionEnd;

        public void Start()
        {
            _sessionStartTime = DateTime.Now;
            _timer = new Timer(60000); // 1 минута
            _timer.Elapsed += TimerOtchot;
            _timer.Start();
        }

        private void TimerOtchot(object sender, ElapsedEventArgs e)
        {
            var OtchotTime = DateTime.Now - _sessionStartTime;
            var remainingTime = _sessionDuration - OtchotTime.TotalMinutes;

            if (remainingTime <= _warningTime && remainingTime > 0)
            {
                OnWarning?.Invoke($"До окончания сеанса осталось {remainingTime} минут.");
            }

            if (remainingTime <= 0)
            {
                _timer.Stop();
                OnSessionEnd?.Invoke();
                BlockLogin();
            }
        }

        private void BlockLogin()
        {

            var blockTime = DateTime.Now.AddMinutes(_blockTime);
            while (DateTime.Now < blockTime) // Блок на 3 минуты
            {
            }
        }
    }
}