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

public class MaterialEntry
{
	public Material material;
	public string shader;
}

public struct ScaleOffset
{
	public Vector2 scale;
	public Vector2 offset;
}

public class LensEffect
{
	#region callbacks
	public delegate void BeforeIterateHandler(CommandBuffer cb);
	public BeforeIterateHandler beforeIterate;

	public delegate void IterationHandler(CommandBuffer cb, BodyPartRenderer renderer);
	public IterationHandler iterate;

	public delegate void AfterIterateHandler(CommandBuffer cb);
	public AfterIterateHandler afterIterate;

	// 这一帧的这个特效结束
	public delegate void FinishRenderHandler();
	public FinishRenderHandler finishRender;
	#endregion 

	private static Dictionary<string/*shaderName*/, List<MaterialEntry>> m_MaterailPool;

	public static LensEffect Create(Func<LensEffect> create)
	{
		return create();
	}

	static LensEffect()
	{
		m_MaterailPool = new Dictionary<string, List<MaterialEntry>>();
	}

	static MaterialEntry ClaimMaterial(string shader)
	{
		List<MaterialEntry> mats;
		if (m_MaterailPool.TryGetValue(shader, out mats) && mats.Count > 0)
		{
			MaterialEntry me = mats[mats.Count - 1];
			mats.RemoveAt(mats.Count - 1);
			return me;
		}
		Material mat = new Material(Shader.Find(shader));
		MaterialEntry entry = new MaterialEntry();
		entry.material = mat;
		entry.shader = shader;
		return entry;
	}

	static void ReleaseMaterial(MaterialEntry entry)
	{
		List<MaterialEntry> mats;
		if (!m_MaterailPool.TryGetValue(entry.shader, out mats))
		{
			mats = new List<MaterialEntry>();
			m_MaterailPool.Add(entry.shader, mats);
		}
		mats.Add(entry);
	}

	#region LensEffects

	public static LensEffect MotionBlur()
	{
		LensEffect eff = LensEffect.Create(() =>
		{
			LensEffect e = new LensEffect();

			List<MaterialEntry> materials = ListPool<MaterialEntry>.Get();
			int tempID = Shader.PropertyToID("_Temp1");

			ScaleOffset scaleOffset = new ScaleOffset();

			e.beforeIterate = (CommandBuffer cb) =>
			{
				cb.GetTemporaryRT(tempID, -1, -1, 24, FilterMode.Bilinear);
				cb.SetRenderTarget(tempID);
				cb.ClearRenderTarget(true, true, new Color(0, 0, 0, 0));
			};
			e.iterate = (CommandBuffer cb, BodyPartRenderer renderer) =>
			{
				Matrix4x4 obj2Wod = Matrix4x4.identity;
				int subMeshCount = 0;
				if (renderer.renderer is SkinnedMeshRenderer)
				{
					SkinnedMeshRenderer smr = renderer.renderer as SkinnedMeshRenderer;
					Vector3 pos = smr.rootBone.transform.position;
					Quaternion rot = smr.rootBone.transform.rotation;
					obj2Wod = MatrixUtility.RotateAndTranslate(pos, rot);
					subMeshCount = smr.sharedMesh.subMeshCount;
				}
				else if (renderer.renderer is MeshRenderer)
				{
					obj2Wod = renderer.renderer.transform.localToWorldMatrix;
					subMeshCount = renderer.renderer.GetComponent<MeshFilter>().sharedMesh.subMeshCount;
				}

				for (int i = 0; i < subMeshCount; ++i)
				{
					MaterialEntry mat = ClaimMaterial(StaticDefine.shaders[EShader.SolidColor].name);
					materials.Add(mat);
					mat.material.SetColor("_Color", Color.red);
					mat.material.SetMatrix("_ObjectToWorld", obj2Wod);

					cb.DrawRenderer(renderer.renderer, mat.material, i);
				}
			};
			e.afterIterate = (CommandBuffer cb) =>
			{
				MaterialEntry blur = ClaimMaterial(StaticDefine.shaders[EShader.Blur].name);
				materials.Add(blur);

				cb.Blit(tempID, BuiltinRenderTextureType.CameraTarget, blur.material);
			};
			e.finishRender = () =>
			{
				for (int i = materials.Count - 1; i >= 0; --i)
				{
					MaterialEntry mat = materials[i];
					ReleaseMaterial(mat);
					materials.RemoveAt(i);
				}
			};
			return e;
		});
		return eff;
	}

	public static LensEffect Glitch()
	{

		return null;
	}

	public static LensEffect OutLine()
	{

		return null;
	}

	public static LensEffect RimLight()
	{
		return null;
	}

	public static LensEffect Decals()
	{
		return null;
	}

	#endregion 
}