using System;

using System.Collections.Generic;

using System.Threading;

​

public class SchedulerService

{

    private static SchedulerService _instance;

    private List<Timer> timers = new List<Timer>();

​

    private SchedulerService() { }

​

    public static SchedulerService Instance => _instance ?? (_instance = new SchedulerService());

​

    public void ScheduleTask(int hour, int min, double intervalInHour, Action task)

    {

        DateTime now = DateTime.Now;

        DateTime firstRun = new DateTime(now.Year, now.Month, now.Day, hour, min, 0, 0);

        if (now > firstRun)

        {

            firstRun = firstRun.AddDays(1);

        }

​

        TimeSpan timeToGo = firstRun - now;

        if (timeToGo <= TimeSpan.Zero)

        {

            timeToGo = TimeSpan.Zero;

        }

​

        var timer = new Timer(x =>

        {

            task.Invoke();

        }, null, timeToGo, TimeSpan.FromHours(intervalInHour));

​

        timers.Add(timer);

    }

}