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

namespace WK
{

    /// <summary>
    /// 作用域范围的消息通知
    /// </summary>
    public class ScopedNotification
    {
        public delegate void NotificatonHandler(params object[] args);

        private Dictionary<string, List<NotificatonHandler>> m_EventListeners = new Dictionary<string, List<NotificatonHandler>>();  

        public void AddObserver(string eventName, NotificatonHandler handler)
        {
            if (handler == null)
            {
                return;
            }

            if (string.IsNullOrEmpty(eventName))
            {
                return;
            }

            List<NotificatonHandler> handlers;
            if (!m_EventListeners.ContainsKey(eventName))
            {
                m_EventListeners.Add(eventName, new List<NotificatonHandler>());
            }

            handlers = m_EventListeners[eventName];
            handlers.Add(handler);  
        }

        public void RemoveObserver(string eventName, NotificatonHandler handler)
        {
            if(handler == null) { return; }     

            if(string.IsNullOrEmpty(eventName)) { return; }

            if (!m_EventListeners.ContainsKey(eventName))
                return;

            List<NotificatonHandler> handlers = m_EventListeners[eventName];    
            if(handlers.Contains(handler))
                handlers.Remove(handler);
        }

        public void RemoveEvent(string eventName)
        {
            if (string.IsNullOrEmpty(eventName)) { return; }
            if(m_EventListeners.ContainsKey(eventName))
            {
                m_EventListeners.Remove(eventName); 
            }
        }

        public void Clean()
        {
            m_EventListeners.Clear();   
        }

        public void PostNotification(string eventName, params object[] args) 
        {
            if (string.IsNullOrEmpty(eventName)) { return; }

            if (!m_EventListeners.ContainsKey(eventName))
                return;

            List<NotificatonHandler> handlers = m_EventListeners[eventName];
            for(int i = 0; i < handlers.Count; i++) 
            {
                var handler = handlers[i];
                if(handler != null) 
                {
                    handler(args);
                }
            }
        }

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

    }

}