using BPASmartClient.Bus.EventBus;
using BPASmartClient.Helper;
using System;
using System.Collections.Concurrent;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

/* ***********************************************
 * subject  事件总线，总线入口，后续按类型分发
 * author   张原川
 * date     2019/6/3 15:49:03 
 * ***********************************************/

namespace LandStation.Bus
{
    public class EventBus : Singleton<EventBus>
    {
        //事件处理委托
        public delegate void EventCallBackHandle(params object[] args);
        //事件处理委托
        public delegate void EventHandle(IEvent @event, EventCallBackHandle callBack = null);
        //事件订阅者集合
        private ConcurrentDictionary<Type, List<EventHandle>> _eventHandls = new ConcurrentDictionary<Type, List<EventHandle>>();

        /// <summary>
        /// 事件订阅
        /// </summary>
        public void Subscribe<TEvent>(EventHandle handle)
        {
            if (!_eventHandls.ContainsKey(typeof(TEvent)))
                _eventHandls.TryAdd(typeof(TEvent), new List<EventHandle>());
            lock (_eventHandls)
                _eventHandls[typeof(TEvent)].Add(handle);
        }

        /// <summary>
        /// 事件退订
        /// </summary>
        public void UnSubscribe<TEvent>(EventHandle handle)
        {
            if (_eventHandls.ContainsKey(typeof(TEvent)))
            {
                if (_eventHandls[typeof(TEvent)].Contains(handle))
                {
                    lock (_eventHandls)
                        _eventHandls[typeof(TEvent)].Remove(handle);
                }
            }
        }

        /// <summary>
        /// 事件发布，不带返回
        /// </summary>
        public void Publish<TEvent>(TEvent @event) where TEvent : IEvent
        {
            if (_eventHandls.ContainsKey(typeof(TEvent)))
            {
                for (int i = _eventHandls[typeof(TEvent)].Count - 1; i >= 0; i--)
                    _eventHandls[typeof(TEvent)][i](@event);

                //_eventHandls[typeof(TEvent)].ForEach(p =>
                //{
                //    p(@event);
                //});
            }
        }

        /// <summary>
        /// 事件发布，带返回
        /// </summary>
        public void Publish<TEvent>(TEvent @event, EventCallBackHandle eventCallBack) where TEvent : IEvent
        {
            List<object> result = new List<object>();
            if (_eventHandls.ContainsKey(typeof(TEvent)))
            {
                //_eventHandls[typeof(TEvent)].ForEach(p =>
                //{
                //    p(@event, delegate (object[] args)
                //    {
                //        result.AddRange(args);
                //    });
                //});

                for (int i = _eventHandls[typeof(TEvent)].Count - 1; i >= 0; i--)
                {
                    _eventHandls[typeof(TEvent)][i](@event, delegate (object[] args)
                    {
                        result.AddRange(args);
                    });
                }

            }
            eventCallBack.Invoke(result.ToArray());
        }

        /// <summary>
        /// 事件总线释放
        /// </summary>
        public void Dispose()
        {
            _eventHandls.Clear();
        }
    }
    
}