telegram-bot/Core/Service/AbstractTimedHostedService.cs

using System;
using System.Threading;
using System.Threading.Tasks;
using BotFramework.Abstractions;
using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.Logging;

namespace Kruzya.TelegramBot.Core.Service;

public abstract class AbstractTimedHostedService : IHostedService, IDisposable
{
    private Timer _timer;
        
    protected readonly ILogger _logger;
    protected readonly IBotInstance _bot;
        
    protected virtual TimeSpan TimerPeriod => TimeSpan.FromSeconds(45);

    protected AbstractTimedHostedService(ILogger logger, IBotInstance bot)
    {
        _bot = bot;
        _logger = logger;
    }

    #region IHostedService

    public Task StartAsync(CancellationToken cancellationToken)
    {
        _logger.LogInformation("Message sender service is starting.");
        _timer = new Timer(Run, null, TimeSpan.Zero, TimerPeriod);

        return Task.CompletedTask;
    }

    public Task StopAsync(CancellationToken cancellationToken)
    {
        _logger.LogInformation("Message sender service is stopping.");
        _timer?.Change(Timeout.Infinite, 0);

        return Task.CompletedTask;
    }
        
    #endregion
    #region IDisposable
    /// <summary>
    /// Disposes the timer.
    /// </summary>
    public void Dispose()
    {
        _timer?.Dispose();
    }
    #endregion

    private async void Run(object state)
    {
        _timer?.Change(Timeout.Infinite, 0);

        try
        {
            await OnRun();
        }
        finally
        {
            var timerPeriod = TimerPeriod;
            _timer?.Change(timerPeriod, timerPeriod);
        }
    }
        
    protected virtual async Task OnRun()
    {
        await Task.Delay(500);
    }
}