using System;
using System.Collections;
using System.Collections.Generic;
using System.Threading;
using System.Threading.Tasks;
using Cysharp.Threading.Tasks;
using Unity.Mathematics;

namespace BITKit.Tween
{

	public static class BITween
	{
		public class TweenSequence
		{
			internal TweenSequence(){}
			private readonly List<UniTask> tasks = new();
			public TweenSequence Append(UniTask task)
			{
				tasks.Add(task);
				return this;
			}
	
			public async UniTask Play(CancellationToken cancellationToken=default)
			{
				foreach (var task in tasks)
				{
					await task;
					if (cancellationToken.IsCancellationRequested) return;
				}
			}
		}
		public static TweenSequence CreateSequence()
		{
			return new TweenSequence();
		}

		public static async UniTask MoveToForward<T>(Action<T> setter, T from, T to, float delta,
			Func<T, T, float, T> func, CancellationToken cancellationToken = default)
		{
			setter(from);
			while (Equals(from,to) is false && cancellationToken.IsCancellationRequested is false)
			{
				from = func(from, to, delta*BITApp.Time.DeltaTime);
#if UNITY_5_3_OR_NEWER
				try
				{
					await UniTask.NextFrame(PlayerLoopTiming.FixedUpdate, cancellationToken);
				}
				catch (OperationCanceledException)
				{
					return;
				}
#else
                
					await UniTask.Yield();
#endif
				setter(from);
			}
			if (cancellationToken.IsCancellationRequested is false)
				setter(to);
		}
		public static async UniTask Lerp<T>(Action<T> setter,T from,T to,float duration, Func<T, T,float, T> func,CancellationToken cancellationToken = default)
		{
			var t = 0f;
			var delta = 1f / duration;
			setter(from);
			//BIT4Log.Log<TweenSequence>($"已创建Tween,from:[{from}]to:[{to}]duration:[{duration}]delta:[{delta}]");
			while (t < 1 && cancellationToken.IsCancellationRequested is false)
			{
				t = math.clamp(t + delta*BITApp.Time.DeltaTime, 0, 1);
				var next = func(from, to, t);
#if UNITY_5_3_OR_NEWER
				await UniTask.NextFrame(cancellationToken);
#else
					await UniTask.Yield();
#endif
				setter(next);
			}
			if (cancellationToken.IsCancellationRequested is false)
				setter(to);
		}
	}
}