using System.Collections.Concurrent;

namespace YLErp.Events
{
    /// <summary>
    /// 事件总线
    /// </summary>
    public static class EventBus
    {
        static readonly Easy.MessageHub.IMessageHub _messageHub;
        static readonly ConcurrentDictionary<Guid, string> _dicSubscribe;

        static EventBus()
        {
            _dicSubscribe = new ConcurrentDictionary<Guid, string>();
            _messageHub = new Easy.MessageHub.MessageHub();
            _messageHub.RegisterGlobalErrorHandler(HandleError);
        }

        //处理事件错误
        private static void HandleError(Guid guid, Exception ex)
        {
            if (ex != null)
            {
                _dicSubscribe.TryGetValue(guid, out var eventName);
                LogFactory.GetLogger(eventName ?? "事件处理").Error(ex);
            }
        }

        /// <summary>
        /// 发布消息
        /// </summary>
        public static void Publish<T>(T message = null) where T : class
        {
            _messageHub.Publish(message);
        }

        /// <summary>
        /// 订阅消息
        /// </summary>
        public static Guid Subscribe<T>(Action<T> action)
        {
            var guid = _messageHub.Subscribe(action);

            var type = typeof(T);
            var attrs = type.GetCustomAttributes(typeof(EventDescriptionAttribute), false);

            string eventName;
            if (attrs != null && attrs.Length > 0)
            {
                var attr = (EventDescriptionAttribute)attrs[0];
                eventName = $"<{type.Name}-{attr.Description}>";
            }
            else
            {
                eventName = $"<{type.Name}>";
            }

            _dicSubscribe[guid] = eventName;

            return guid;
        }

        /// <summary>
        /// 订阅消息
        /// </summary>
        public static void Unsubscribe(Guid token)
        {
            try
            {
                _messageHub.Unsubscribe(token);
            }
            catch { }

            _dicSubscribe.TryRemove(token, out _);
        }
    }
}