using System;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.Extensions.Logging;

namespace xCommons.Providers
{
    /// <summary>
    /// Resumable Background Task ...
    /// </summary>
    public abstract class XResumableBackgroundService : XBackgroundService
    {
        /// <summary>
        /// Check is Paused ...
        /// </summary>
        protected bool paused = false;

        protected XResumableBackgroundService(
            IServiceProvider serviceProvider,
            ILogger<XResumableBackgroundService> logger
        ) : base(
            logger: logger,
            serviceProvider: serviceProvider
        )
        { }

        protected override async Task ExecuteAsync(
            CancellationToken stoppingToken = default
        )
        {
            //
            if (paused)
            {
                return;
            }

            //
            await DoWorkAsync(
                payload: null,
                cancellationToken: stoppingToken
            );
        }

        /// <summary>
        /// do all required works here ...
        /// </summary>
        /// <param name="payload"></param>
        /// <param name="cancellationToken"></param>
        /// <returns></returns>
        public abstract Task DoWorkAsync(
            object payload = null,
            CancellationToken cancellationToken = default
        );

        /// <summary>
        /// Pause Consuming ...
        /// </summary>
        /// <returns></returns>
        public bool Pause()
        {
            //
            var result = !paused;
            if (!result)
            {
                return result;
            }

            //
            paused = true;
            result = paused;
            return result;
        }

        /// <summary>
        /// Resume Consuming ...
        /// </summary>
        /// <returns></returns>
        public bool Resume()
        {
            //
            var result = paused;
            if (!result)
            {
                return result;
            }

            //
            paused = false;
            result = !paused;
            return result;
        }
    }
}