using System;
using System.Collections.Concurrent;
using System.Collections.Generic;
using System.Text;

namespace ShrlAlgoToolkit.RevitCore.Base
{
    public class ActionEventHandler : IExternalEventHandler
    {
        // 线程安全队列，用于存储需要传递给主线程执行的委托
        private readonly ConcurrentQueue<Action<UIApplication>> _tasks = new ConcurrentQueue<Action<UIApplication>>();
        private readonly ExternalEvent _externalEvent;

        public ActionEventHandler()
        {
            _externalEvent = ExternalEvent.Create(this);
        }

        public void Execute(UIApplication app)
        {
            // 当主线程被 ExternalEvent 唤醒时，一次性执行队列中积累的所有任务
            while (_tasks.TryDequeue(out var action))
            {
                action?.Invoke(app);
            }
        }

        public string GetName() => "AsyncActionEventHandler";

        // 无返回值的异步任务
        public Task RaiseAsync(Action<UIApplication> action)
        {
            var tcs = new TaskCompletionSource<bool>();
            _tasks.Enqueue(app =>
            {
                try
                {
                    action(app);
                    tcs.SetResult(true);
                }
                catch (Exception ex)
                {
                    tcs.SetException(ex);
                }
            });

            _externalEvent.Raise(); // 通知 Revit 唤醒事件
            return tcs.Task;
        }

        // 有返回值的异步任务
        public Task<T> RaiseAsync<T>(Func<UIApplication, T> func)
        {
            var tcs = new TaskCompletionSource<T>();
            _tasks.Enqueue(app =>
            {
                try
                {
                    var result = func(app);
                    tcs.SetResult(result);
                }
                catch (Exception ex)
                {
                    tcs.SetException(ex);
                }
            });

            _externalEvent.Raise();
            return tcs.Task;
        }
    }
}