using System;
using System.Collections;
using System.Collections.Generic;
using UnityEngine;

namespace BitStrap
{
	public class TweenShader : MonoBehaviour
	{
		[Serializable]
		public class ShaderProperty
		{
			public enum Type
			{
				Color = 0,
				Float = 1
			}

			public string name;

			public Color from = Color.white;

			public Color to = Color.white;

			public Type type = Type.Float;

			private int? id;

			public int Id
			{
				get
				{
					if (!id.HasValue)
					{
						id = Shader.PropertyToID(name);
					}
					return id.Value;
				}
			}

			public void Evaluate(MaterialPropertyBlock block, float t)
			{
				if (type == Type.Color)
				{
					block.SetColor(Id, Color.Lerp(from, to, t));
				}
				else if (type == Type.Float)
				{
					block.SetFloat(Id, Mathf.Lerp(from.a, to.a, t));
				}
			}
		}

		public AnimationCurve curve = AnimationCurve.Linear(0f, 0f, 1f, 1f);

		public float duration = 1f;

		public List<ShaderProperty> shaderProperties;

		public Renderer targetRenderer;

		private MaterialPropertyBlock propertyBlock;

		public void Clear()
		{
			propertyBlock.Clear();
			targetRenderer.SetPropertyBlock(propertyBlock);
		}

		public void Evaluate(float t)
		{
			propertyBlock.Clear();
			t = curve.Evaluate(t);
			foreach (ShaderProperty shaderProperty in shaderProperties)
			{
				shaderProperty.Evaluate(propertyBlock, t);
			}
			targetRenderer.SetPropertyBlock(propertyBlock);
		}

		public void PlayBackward()
		{
			Stop();
			StartCoroutine(PlayAsync(1f, 0f));
		}

		public void PlayForward()
		{
			Stop();
			StartCoroutine(PlayAsync(0f, 1f));
		}

		public void Stop()
		{
			StopAllCoroutines();
		}

		private void Awake()
		{
			propertyBlock = new MaterialPropertyBlock();
			if (targetRenderer == null)
			{
				targetRenderer = GetComponent<Renderer>();
			}
		}

		private IEnumerator PlayAsync(float from, float to)
		{
			for (float time = 0f; time < duration; time += Time.deltaTime)
			{
				float t = Mathf.Lerp(from, to, Mathf.InverseLerp(0f, duration, time));
				Evaluate(t);
				yield return null;
			}
			Evaluate(to);
		}

		private void Reset()
		{
			targetRenderer = GetComponent<Renderer>();
		}
	}
}