// -----------------------------------------------------------------------
// <copyright file="JobQueue.cs" company="Microsoft">
// TODO: Update copyright text.
// </copyright>
// -----------------------------------------------------------------------

using System.Collections.Concurrent;
using System.Threading;
using System.Threading.Tasks;

namespace Pithos.Core
{
    using System;
    using System.Collections.Generic;
    using System.Linq;
    using System.Text;

    /// <summary>
    /// TODO: Update summary.
    /// </summary>
    public class JobQueue
    {
        private readonly BlockingCollection<Action> _statusUpdateQueue = new BlockingCollection<Action>();
        private CancellationToken _cancellationToken;
        

        public void Start(CancellationToken token)
        {
            _cancellationToken = token;
            Task.Factory.StartNew(ProcessUpdates, _cancellationToken);
        }

        private void ProcessUpdates()
        {
            foreach (var action in _statusUpdateQueue.GetConsumingEnumerable())
            {
                action();
            }
        }

        public void Add(Action action)
        {
            _statusUpdateQueue.Add(action);
        }

        public void Stop()
        {
            _statusUpdateQueue.CompleteAdding();
        }
       
    }   

    public class JobAgent:Agent<Action>
    {
        protected JobAgent(Action<Agent<Action>>  action)
            :base(action)
        {
            
        }

        public static JobAgent Create()
        {
            return (JobAgent)Start(queue =>
            {
                Action loop = null;
                loop = () =>
                {
                    var job = queue.Receive();
                    job.ContinueWith(t =>
                    {
                        t.IgnoreExceptions();
                        var action = job.Result;
                        action();
                        queue.DoAsync(loop);
                    });
                };
                loop();
            });
        }

    }
}