using System.Collections;
using System.Threading.Tasks;

using RobocraftX.Schedulers;
using Svelto.ECS;
using Svelto.Tasks.ExtraLean;

using GamecraftModdingAPI.Engines;

namespace GamecraftModdingAPI.Utility
{
    public class AsyncUtilsEngine : IApiEngine
    {
        private IEntityFunctions _efu;
        private IEntityFactory _efa;
        private IEnumerator WaitForSubmissionInternal(IEntityFunctions efu, IEntityFactory efa,
            EntitiesDB entitiesDB, TaskCompletionSource<object> task)
        {
            var waitEnumerator = new WaitForSubmissionEnumerator(efu, efa, entitiesDB);
            while (waitEnumerator.MoveNext())
                yield return null;
            task.SetResult(null);
        }

        private IEnumerator WaitForNextFrameInternal(TaskCompletionSource<object> task)
        {
            yield return null;
            task.SetResult(null);
        }

        public Task WaitForSubmission()
        {
            var task = new TaskCompletionSource<object>();
            WaitForSubmissionInternal(_efu, _efa, entitiesDB, task).RunOn(ExtraLean.EveryFrameStepRunner_TimeStopped);
            return task.Task;
        }

        public Task WaitForNextFrame()
        {
            var task = new TaskCompletionSource<object>();
            WaitForNextFrameInternal(task).RunOn(ExtraLean.EveryFrameStepRunner_TimeStopped);
            return task.Task;
        }

        public void Setup(IEntityFunctions efu, IEntityFactory efa)
        {
            _efu = efu;
            _efa = efa;
        }

        public void Ready()
        {
        }

        public EntitiesDB entitiesDB { get; set; }
        public void Dispose()
        {
        }

        public string Name { get; } = "GamecraftModdingAPIAsyncUtilsGameEngine";
        public bool isRemovable { get; } = false;
    }
}