using System;
using System.Collections.Generic;
using UnityEngine;

namespace WK
{

    public sealed class NotificationCenter : Singleton<NotificationCenter> 
    {
        public delegate void NotificatonHandler(params object[] args);

        private Dictionary<string/*eventName*/, Dictionary<object/*publisher*/, List<NotificatonHandler>>> m_EventListeners = new Dictionary<string, Dictionary<object, List<NotificatonHandler>>>();

        /// <summary>
        /// 当前在调用中的回调
        /// </summary>
        private HashSet<List<NotificatonHandler>> m_CurInvokingCallbacks = new HashSet<List<NotificatonHandler>>();

        public void AddObserver(string notificationName, NotificatonHandler handler)
        {
            AddObserver(null, notificationName, handler);
        }

        public void AddObserver(object sender, string notificationName, NotificatonHandler handler)
        {
            if (handler == null)
            {
                Debug.LogError("Can't add a null event handler for notification, " + notificationName);
                return;
            }
            if (string.IsNullOrEmpty(notificationName))
            {
                Debug.LogError("Can't observe an unnamed notification");
                return;
            }
            if (!m_EventListeners.ContainsKey(notificationName))
            {
                m_EventListeners.Add(notificationName, new Dictionary<object, List<NotificatonHandler>>());
            }
            Dictionary<object, List<NotificatonHandler>> dictionary = m_EventListeners[notificationName];
            object key = ((sender != null) ? sender : this);
            if (!dictionary.ContainsKey(key))
            {
                dictionary.Add(key, new List<NotificatonHandler>());
            }
            List<NotificatonHandler> list = dictionary[key];
            if (m_CurInvokingCallbacks.Contains(list))
            {
                list = (dictionary[key] = new List<NotificatonHandler>(list));
            }
            list.Add(handler);
        }

        public void RemoveObserver(string notificationName, NotificatonHandler handler)
        {
            RemoveObserver(null, notificationName, handler);
        }

        public void RemoveObserver(object sender, string notificationName, NotificatonHandler handler)
        {
            if (handler == null)
            {
                Debug.LogError("Can't remove a null event handler for notification, " + notificationName);
            }
            else if (string.IsNullOrEmpty(notificationName))
            {
                Debug.LogError("A notification name is required to stop observation");
            }
            else
            {
                if (!m_EventListeners.ContainsKey(notificationName))
                {
                    return;
                }
                Dictionary<object, List<NotificatonHandler>> dictionary = m_EventListeners[notificationName];
                object key = ((sender != null) ? sender : this);
                if (!dictionary.ContainsKey(key))
                {
                    return;
                }
                List<NotificatonHandler> list = dictionary[key];
                int num = list.IndexOf(handler);
                if (num != -1)
                {
                    if (m_CurInvokingCallbacks.Contains(list))
                    {
                        list = (dictionary[key] = new List<NotificatonHandler>(list));
                    }
                    list.RemoveAt(num);
                }
            }
        }

        public void Clean()
        {
            string[] array = new string[m_EventListeners.Keys.Count];
            m_EventListeners.Keys.CopyTo(array, 0);
            for (int num = array.Length - 1; num >= 0; num--)
            {
                string key = array[num];
                Dictionary<object, List<NotificatonHandler>> dictionary = m_EventListeners[key];
                object[] array2 = new object[dictionary.Keys.Count];
                dictionary.Keys.CopyTo(array2, 0);
                for (int num2 = array2.Length - 1; num2 >= 0; num2--)
                {
                    object key2 = array2[num2];
                    if (dictionary[key2].Count == 0)
                    {
                        dictionary.Remove(key2);
                    }
                }
                if (dictionary.Count == 0)
                {
                    m_EventListeners.Remove(key);
                }
            }
        }

        public void PostNotification(string notificationName)
        {
            PostNotification(notificationName, null);
        }

        public void PostNotification(object sender, string notificationName)
        {
            PostNotification(sender, notificationName, null);
        }

        public void PostNotification(object sender, string notificationName, params object[] p)
        {
            if (string.IsNullOrEmpty(notificationName))
            {
                Debug.LogError("A notification name is required");
            }
            else
            {
                if (!m_EventListeners.ContainsKey(notificationName))
                {
                    return;
                }
                Dictionary<object, List<NotificatonHandler>> dictionary = m_EventListeners[notificationName];
                if (sender != null && dictionary.ContainsKey(sender))
                {
                    List<NotificatonHandler> list = dictionary[sender];
                    m_CurInvokingCallbacks.Add(list);
                    for (int i = 0; i < list.Count; i++)
                    {
                        list[i](p);
                    }
                    m_CurInvokingCallbacks.Remove(list);
                }
                if (dictionary.ContainsKey(this))
                {
                    List<NotificatonHandler> list2 = dictionary[this];
                    m_CurInvokingCallbacks.Add(list2);
                    for (int j = 0; j < list2.Count; j++)
                    {
                        list2[j](p);
                    }
                    m_CurInvokingCallbacks.Remove(list2);
                }
            }
        }

    }

}