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

namespace Tuan.GameFramework
{
    public static class EventBus
    {

        private static readonly Dictionary<Type, object> _eventHandlers = new Dictionary<Type, object>();
        private static readonly object _lock = new object();

        public static void Register<TEvent>(IEventHandler<TEvent> handler) where TEvent : IEvent
        {
            lock (_lock)
            {
                Type eventType = typeof(TEvent);
                if (!_eventHandlers.ContainsKey(eventType))
                {
                    _eventHandlers[eventType] = new List<IEventHandler<TEvent>>();
                }

                var handlers = _eventHandlers[eventType] as List<IEventHandler<TEvent>>;
                if (handler != null && !handlers.Contains(handler))
                {
                    handlers.Add(handler);
                }
            }
        }

        public static void Unregister<TEvent>(IEventHandler<TEvent> handler) where TEvent : IEvent
        {
            lock (_lock)
            {
                Type eventType = typeof(TEvent);
                if (_eventHandlers.ContainsKey(eventType))
                {
                    var handlers = _eventHandlers[eventType] as List<IEventHandler<TEvent>>;
                    handlers?.Remove(handler);

                    if (handlers != null && handlers.Count == 0)
                    {
                        _eventHandlers.Remove(eventType);
                    }
                }
            }
        }

        public static void Publish<TEvent>(TEvent eventData) where TEvent : IEvent
        {
            List<IEventHandler<TEvent>> handlersToInvoke = null;

            lock (_lock)
            {
                Type eventType = typeof(TEvent);
                if (_eventHandlers.ContainsKey(eventType))
                {
                    var handlers = _eventHandlers[eventType] as List<IEventHandler<TEvent>>;
                    if (handlers != null && handlers.Count > 0)
                    {
                        handlersToInvoke = new List<IEventHandler<TEvent>>(handlers);
                    }
                }
            }

            // 在锁外执行事件处理，避免死锁
            if (handlersToInvoke != null)
            {
                foreach (var handler in handlersToInvoke)
                {
                    try
                    {
                        handler?.HandleEvent(eventData);
                    }
                    catch (Exception e)
                    {
                        Debug.LogError($"Event handling error in {handler.GetType().Name}: {e}");
                    }
                }
            }
        }

        public static void Clear()
        {
            lock (_lock)
            {
                _eventHandlers.Clear();
            }
        }
    }
}