using Microsoft.Extensions.Logging;

namespace WarcViewerBlazorWinForm.Library.EventBus
{
    public abstract class InProcessEventBusBase(ILogger<InProcessEventBusBase> logger) : IEventBus
    {
        private readonly Dictionary<Type, HashSet<Delegate>> _dicTypeToHandlers = new();

        public bool Subscript<T>(Action<T> callBack)
        {
            var type = typeof(T);
            lock (_dicTypeToHandlers)
            {
                if (!_dicTypeToHandlers.TryGetValue(type, out var handlers))
                {
                    handlers = _dicTypeToHandlers[type] = new();
                }

                return handlers.Add(callBack); // 忽略重复
            }
        }

        public bool UnSubscript<T>(Action<T> callBack)
        {
            lock (_dicTypeToHandlers)
            {
                if (_dicTypeToHandlers.TryGetValue(typeof(T), out var handlers))
                {
                    var unSubscript = handlers.Remove(callBack);

                    if (handlers.Count == 0) _dicTypeToHandlers.Remove(typeof(T));

                    return unSubscript;
                }

                return false;
            }
        }

        public bool Publish<T>()
        {
            PublishInternal(new AnyPublishEvent(typeof(T), default));
            return PublishInternal<T>(default);
        }

        public bool Publish<T>(T obj)
        {
            PublishInternal(new AnyPublishEvent(typeof(T), obj));
            return PublishInternal(obj);
        }

        private bool PublishInternal<T>(T eventValue)
        {
            var type = typeof(T);

            Delegate[] subscripts;
            lock (_dicTypeToHandlers)
            {
                if (!_dicTypeToHandlers.TryGetValue(type, out var handlers)) return false;
                subscripts = handlers.ToArray();
            }

            foreach (var del in subscripts)
            {
                try
                {
                    ((Action<T>)del)(eventValue);
                }
                catch (Exception e)
                {
                    logger.LogError(e, nameof(Publish));
                }
            }

            return true;
        }
    }
}