using System;
using System.IO;
using System.Linq;
using System.Text;
using Quadarax.Foundation.Core.Business.Exceptions;
using Quadarax.Foundation.Core.Object;
using Quadarax.Foundation.Core.Value.Extensions;

namespace Quadarax.Foundation.Core.Business.ProcessQueue
{
    public class QueueItem : DisposableObject, IQueueItem
    {

        public QueueItemStateEnum State { get; protected set;}
        public DateTime Created { get; }
        public DateTime? Modified { get; }
        public DateTime? Started { get; }
        public DateTime? Finished { get; }
        public DateTime StartFrom { get; }
        public DateTime? StartTo { get; }
        public string Affinity { get; protected set; }
        public int Priority { get; }

        public void Assign(string assignTo)
        {
            if (!string.IsNullOrEmpty(Affinity) && !string.IsNullOrEmpty(assignTo))
                throw new InvalidStateException(
                    $"Query item '{GetIdentifier()}' has already set Affinity to '{Affinity}'");

            ValidateState("set Affinity", QueueItemStateEnum.New, QueueItemStateEnum.Paused);

            ends here


            Affinity = assignTo;
            
        }

        public void Start()
        {
            throw new NotImplementedException();
        }

        public void Stop()
        {
            throw new NotImplementedException();
        }

        public void Pause()
        {
            throw new NotImplementedException();
        }

        public string GetIdentifier()
        {
            return OnGetIdentifer();
        }


        protected void ValidateState(string operationName, params QueueItemStateEnum[] allowedStates)
        {
            if (string.IsNullOrEmpty(operationName)) throw new ArgumentNullException(nameof(operationName));

            if (allowedStates.Length==0)
                return;

            if (!State.In(allowedStates))
                throw new InvalidStateException(
                    $"Query item '{GetIdentifier()}' has invalid state to {operationName} (expecting. {string.Join(",", allowedStates.Select(x=>x.ToString()))}");

        }

        protected virtual string OnGetIdentifer()
        {
            var sb = new StringBuilder();
            sb.Append("QI").Append(Created.ToFileTimeUtc()).Append("_").Append(StartFrom.ToFileTimeUtc()).Append("_")
                .Append(string.IsNullOrEmpty(Affinity) ? 0 : Affinity.GetHashCode());
            return sb.ToString();
        }

        protected override void OnDisposing()
        {
        }
    }
}