using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
 
namespace Pangea.Common.Utility
{
    /// <summary>
    /// Publisher/Subscriber pattern
    /// This infrastructure works as an instance.
    /// </summary>
    public sealed class Publisher<EventType> where EventType : IComparable
    {
        private static readonly object _locker = new object();
 
        private static readonly Dictionary<EventType, List<Action<object, object, object, object>>> _eventTypeList = new Dictionary<EventType, List<Action<object, object, object, object>>>();
 
        public static void Attach(EventType key, Action<object, object, object, object> act)
        {
            lock (_locker)
            {
                if (!_eventTypeList.ContainsKey(key))
                    _eventTypeList.Add(key, new List<Action<object, object, object, object>>());
                if (!_eventTypeList[key].Contains(act))
                    _eventTypeList[key].Add(act);
            }
        }
 
        public static void Detach(EventType key)
        {
            lock (_locker)
            {
                if (_eventTypeList.ContainsKey(key))
                {
                    _eventTypeList[key].Clear();
                }
            }
        }
 
        public static void Detach(EventType key, Action<object, object, object, object> act)
        {
            lock (_locker)
            {
                if (_eventTypeList.ContainsKey(key) && _eventTypeList[key].Contains(act))
                {
                    _eventTypeList[key].Remove(act);
                }
            }
        }
 
        public static void Notify(EventType key, object p1, object p2, object p3, object p4)
        {
            lock (_locker)
            {
                if (_eventTypeList.ContainsKey(key))
                {
                    foreach (var act in _eventTypeList[key])
                    {
                        act.Invoke(p1, p2, p3, p4);
                    }
                }
            }
        }
 
        public static void Notify(EventType key, object p1, object p2, object p3)
        {
            Notify(key, p1, p2, p3, null);
        }
 
        public static void Notify(EventType key, object p1, object p2)
        {
            Notify(key, p1, p2, null, null);
        }
 
        public static void Notify(EventType key, object p1)
        {
            Notify(key, p1, null, null, null);
        }
 
        public static void Notify(EventType key)
        {
            Notify(key, null, null, null, null);
        }
    }
}