using System;
using System.Linq;
using Hangfire.States;

namespace Kreta.Job.Tasks.Core
{
    public class JobStateWatcherAttribute : Hangfire.Common.JobFilterAttribute, Hangfire.States.IElectStateFilter
    {
        public OnAttemptsReached AttemptsReached { get; set; }

        public JobStateWatcherAttribute(Type delegateInstance, string delegateName)
        {
            try
            {
                AttemptsReached = (OnAttemptsReached)Delegate.CreateDelegate(typeof(OnAttemptsReached), delegateInstance, delegateName);
            }
            catch (Exception ex)
            {
                throw new ApplicationException("OnAttemptsReached típusúnak kell lennie a delegáltnak.", ex);
            }
        }

        public void OnStateElection(ElectStateContext context)
        {
            var state = context.CandidateState as FailedState;
            if (state == null)
            {
                return;
            }

            var actualRetryCount = context.GetJobParameter<int>("RetryCount");
            var automaticRetryAttribute = context.BackgroundJob.Job.Method.CustomAttributes.FirstOrDefault(x => x.AttributeType == typeof(Hangfire.AutomaticRetryAttribute));
            if (automaticRetryAttribute != null)
            {
                var attempts = automaticRetryAttribute.NamedArguments.FirstOrDefault(x => x.MemberName == "Attempts");
                if (attempts.MemberInfo != null)
                {
                    int maxRetryCounts = (int)attempts.TypedValue.Value;
                    if (maxRetryCounts == actualRetryCount)
                    {
                        AttemptsReached?.Invoke(context.BackgroundJob.Id);
                    }
                }
            }
        }
    }
}