using System;
using System.Threading.Tasks;

namespace AibisDream.Kit
{
    public class TaskAction : IAction
    {
        private static readonly SimpleObjectPool<TaskAction> Pool = new(() => new TaskAction(), null, 10);

        private Func<Task> _taskGetter;
        private Task _executingTask;

        private TaskAction()
        {
        }

        public static TaskAction Allocate(Func<Task> taskGetter)
        {
            var coroutineAction = Pool.Allocate();
            coroutineAction.ActionID = ActionKit.IDGenerator++;
            coroutineAction.IsFinalized = false;
            coroutineAction.Reset();
            coroutineAction._taskGetter = taskGetter;
            return coroutineAction;
        }

        public bool Paused { get; set; }

        public void Deinit()
        {
            if (!IsFinalized)
            {
                IsFinalized = true;
                _taskGetter = null;
                if (_executingTask != null)
                {
                    _executingTask.Dispose();
                    _executingTask = null;
                }

                ActionKitMonoBehaviourEvents.AddCallback(new ActionQueueRecycleCallback<TaskAction>(Pool, this));
            }
        }

        public void Reset()
        {
            Paused = false;
            Status = ActionStatus.NotStart;
        }

        public bool IsFinalized { get; set; }
        public ulong ActionID { get; set; }
        public ActionStatus Status { get; set; }

        public void OnStart()
        {
            StartTask();
        }

        async void StartTask()
        {
            _executingTask = _taskGetter();
            await _executingTask;
            Status = ActionStatus.Finished;
            _executingTask = null;
        }

        public void OnExecute(float dt)
        {
        }

        public void OnFinish()
        {
        }
    }

    public static class TaskExtension
    {
        public static ISequence Task(this ISequence self, Func<Task> taskGetter)
        {
            return self.Append(TaskAction.Allocate(taskGetter));
        }

        public static IAction ToAction(this Task self)
        {
            return TaskAction.Allocate(() => self);
        }
    }
}