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

//https://docs.unity3d.com/ScriptReference/Rendering.RenderTargetIdentifier.html

// Unit效果之一，镜头效果，通过command buffer实现

public class UnitLensEffect : UnitComponent
{
	private List<RendererProxy> renderers;

	private static ObjectPool<CommandBuffer> m_CommandBufferPool;

	private List<LensEffect> m_Effects;

	private CommandBuffer m_CommandBuffer;

	static UnitLensEffect()
	{
		m_CommandBufferPool = new ObjectPool<CommandBuffer>(null, null);
	}

	public override void Initialize()
	{
		base.Initialize();

		renderers = new List<RendererProxy>();
		m_Effects = new List<LensEffect>();
	}

	public override void OnPostInitialize()
	{
		base.OnPostInitialize();

		IBodyRendererAgent body = owner.unitRender.body;
		if (body == null || body.renderers == null)
			return;
		for (int i = 0; i < body.renderers.Length; ++i)
		{
			var renderer = body.renderers[i];
			if (renderer == null)
				continue;
			RendererProxy proxy = renderer.renderer.gameObject.GetOrAddComponent<RendererProxy>();
			proxy.Initialize(renderer);
			proxy.onWillRenderObject = OnWillRenderObj;
			proxy.onRenderObject = OnRenderObj;
			renderers.Add(proxy);
		}

		m_CommandBuffer = ClaimCommandBuffer();
		m_CommandBuffer.name = "Unit Render";

		MainCamera.Instance.lensEffectHandler.onPreCull += OnWillRenderUnit;
		MainCamera.Instance.lensEffectHandler.onPostRender += OnRenderUnit;

		/////
		m_Effects.Add(LensEffect.MotionBlur());
	}

	public override void Release()
	{
		base.Release();

		MainCamera.Instance.lensEffectHandler.onPreRender -= OnWillRenderUnit;
		MainCamera.Instance.lensEffectHandler.onPostRender -= OnRenderUnit;
	}

	private void OnWillRenderUnit()
	{
		IBodyRendererAgent body = owner.unitRender.body;
		if (body == null || body.renderers == null)
			return;
		if (m_Effects == null || m_Effects.Count == 0)
			return;

		m_CommandBuffer.Clear();

		for (int i = 0; i < m_Effects.Count; ++i)
		{
			m_Effects[i].beforeIterate(m_CommandBuffer);
			for (int j = 0; j < body.renderers.Length; ++j)
			{
				var renderer = body.renderers[j];
				if (renderer == null)
					continue;
				m_Effects[i].iterate(m_CommandBuffer,renderer);
			}
			m_Effects[i].afterIterate(m_CommandBuffer);
		}

		MainCamera.Instance.camera.AddCommandBuffer(CameraEvent.AfterImageEffectsOpaque, m_CommandBuffer);
	}

	private void OnRenderUnit()
	{
		MainCamera.Instance.camera.RemoveCommandBuffer(CameraEvent.AfterImageEffectsOpaque, m_CommandBuffer);
		for(int i = 0; i < m_Effects.Count; ++i)
		{
			m_Effects[i].finishRender?.Invoke();
		}
	}

	private void OnWillRenderObj(BodyPartRenderer renderer)
	{
	}

	private void OnRenderObj(BodyPartRenderer renderer)
	{
	}

	static CommandBuffer ClaimCommandBuffer()
	{
		CommandBuffer cb = m_CommandBufferPool.Get();
		cb.Clear();
		return cb;
	}

	static void ReleaseCommandBuffer(ref CommandBuffer cb)
	{
		m_CommandBufferPool.Release(cb);
		cb = null;
	}

}