using System;
using System.Collections.Generic;

namespace SUISS.Core
{
    public class Messenger
    {
        public void Subscribe<T>(Action<T> callback) where T : class
        {
            Action<object> action = delegate (object o)
            {
                callback((T)((object)o));
            };
            if (this.events.ContainsKey(typeof(T)))
            {
                this.events[typeof(T)] = (Action<object>)Delegate.Combine(this.events[typeof(T)], action);
            }
            else
            {
                this.events.Add(typeof(T), action);
            }
            this.lookupTable.Add(callback, action);
        }

        public void Unsubscribe<T>(Action<T> callback) where T : class
        {
            if (this.events.ContainsKey(typeof(T)) && this.lookupTable.ContainsKey(callback))
            {
                (this.events)[typeof(T)] = (Action<object>)Delegate.Remove(this.events[typeof(T)], this.lookupTable[callback]);
                this.lookupTable.Remove(callback);
            }
        }

        public void Invoke<T>(T evt) where T : class
        {
            Action<object> action;
            if (this.events.TryGetValue(typeof(T), out action) && action != null)
            {
                action(evt);
            }
        }

        private Dictionary<Type, Action<object>> events = new Dictionary<Type, Action<object>>();

        private Dictionary<object, Action<object>> lookupTable = new Dictionary<object, Action<object>>();
    }
}