using System;
using System.Threading;
using System.Windows.Forms;
using System.ComponentModel;
using Microsoft.Win32.SafeHandles;
using System.Runtime.InteropServices;

namespace WakeUPTimer
{
    public class WaitableTimer
    {
        [DllImport("kernel32.dll")]
        private static extern SafeWaitHandle CreateWaitableTimer(
            IntPtr lpTimerAttributes,
            bool bManualReset,
            string lpTimerName);
        [DllImport("kernel32.dll", SetLastError = true)]
        [return: MarshalAs(UnmanagedType.Bool)]
        private static extern bool SetWaitableTimer(
            SafeWaitHandle hTimer,
            [In] ref long pDueTime,
            int lPeriod,
            IntPtr pfnCompletionRoutine,
            IntPtr lpArgToCompletionRoutine,
            bool fResume);

        //public event EventHandler Woken;

        public WaitableTimer(TimeSpan delay)
        {
            WakeUP();
            bgWorker.RunWorkerAsync(-delay.Ticks);
        }
        public WaitableTimer(DateTime wakeup_time)
        {
            WakeUP();
            bgWorker.RunWorkerAsync(wakeup_time.Ticks);
        }

        private BackgroundWorker bgWorker; // тот же Thread, только в профиль

        private void bgWorker_DoWork(object sender, DoWorkEventArgs e)
        {
            long waketime=(long)e.Argument;
            using (SafeWaitHandle handle=CreateWaitableTimer(
                IntPtr.Zero,true,this.GetType().Assembly.GetName().Name.ToString()+"MyWaitableTimer"))
            {
                if (SetWaitableTimer(handle,ref waketime,0,IntPtr.Zero,IntPtr.Zero,true))
                {
                    using (EventWaitHandle wh=new EventWaitHandle(false,EventResetMode.AutoReset))
                    {
                        wh.SafeWaitHandle=handle;
                        wh.WaitOne();
                    }
                } else
                {
                    //throw new Win32Exception(Marshal.GetLastWin32Error());
                    Exception error=new Win32Exception(Marshal.GetLastWin32Error());
                    MessageBox.Show("Что то пошло не так ...\r\n\r\n"+error.Message,"Ой ...");
                }
            }
        }
        /*private void bgWorker_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
        {
            /* if (Woken!=null)
                Woken(this,new EventArgs());
            else {}
            MessageBox.Show("Интересна ...","Хм ...");
        }*/
        private void WakeUP()
        {
            if (bgWorker==null)
            {
                bgWorker=new BackgroundWorker();
                bgWorker.DoWork+=new DoWorkEventHandler(bgWorker_DoWork);
            } else {}
            //bgWorker.RunWorkerCompleted+=new RunWorkerCompletedEventHandler(bgWorker_RunWorkerCompleted);
        }

    }
}