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

namespace WK
{

    public class NotificationCenter
    {
        private Dictionary<string, Dictionary<object, List<Action<object, object>>>> _table = new Dictionary<string, Dictionary<object, List<Action<object, object>>>>();

        private HashSet<List<Action<object, object>>> _invoking = new HashSet<List<Action<object, object>>>();

        public static readonly NotificationCenter instance = new NotificationCenter();

        private NotificationCenter()
        {
        }

        public void AddObserver(Action<object, object> handler, string notificationName)
        {
            AddObserver(handler, notificationName, null);
        }

        public void AddObserver(Action<object, object> handler, string notificationName, object sender)
        {
            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 (!_table.ContainsKey(notificationName))
            {
                _table.Add(notificationName, new Dictionary<object, List<Action<object, object>>>());
            }
            Dictionary<object, List<Action<object, object>>> dictionary = _table[notificationName];
            object key = ((sender != null) ? sender : this);
            if (!dictionary.ContainsKey(key))
            {
                dictionary.Add(key, new List<Action<object, object>>());
            }
            List<Action<object, object>> list = dictionary[key];
            if (_invoking.Contains(list))
            {
                list = (dictionary[key] = new List<Action<object, object>>(list));
            }
            list.Add(handler);
        }

        public void RemoveObserver(Action<object, object> handler, string notificationName)
        {
            RemoveObserver(handler, notificationName, null);
        }

        public void RemoveObserver(Action<object, object> handler, string notificationName, object sender)
        {
            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 (!_table.ContainsKey(notificationName))
                {
                    return;
                }
                Dictionary<object, List<Action<object, object>>> dictionary = _table[notificationName];
                object key = ((sender != null) ? sender : this);
                if (!dictionary.ContainsKey(key))
                {
                    return;
                }
                List<Action<object, object>> list = dictionary[key];
                int num = list.IndexOf(handler);
                if (num != -1)
                {
                    if (_invoking.Contains(list))
                    {
                        list = (dictionary[key] = new List<Action<object, object>>(list));
                    }
                    list.RemoveAt(num);
                }
            }
        }

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

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

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

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

}