using System.Collections.Generic;
using System.Linq;
using UnityEngine;
using UnityEngine.Rendering;
using UnityEngine.Rendering.RenderGraphModule;
using UnityEngine.Rendering.Universal;

namespace SLSFramework.Rendering.PostProcessing
{
    public class ScriptablePostProcessorPass : ScriptableRenderPass
    {
        private List<ScriptablePostProcessorVolume> postProcessors;
        private List<int> activePostProcessorIndex;

        private string profilerTag;
        private List<ProfilingSampler> profilingSamplers;
        

        public ScriptablePostProcessorPass(string profilerTag, List<ScriptablePostProcessorVolume> postProcessors)
        {
            this.profilerTag = profilerTag;
            this.postProcessors = postProcessors;
            activePostProcessorIndex = new List<int>(postProcessors.Count);
            profilingSamplers = postProcessors.Select(c => new ProfilingSampler(c.ToString())).ToList();
        }
        
        private RenderingData m_RenderingData;

        private class PassData
        {
            public TextureHandle SourceTexture;
            public TextureHandle TargetTexture;
            public TextureHandle TempTextureA;
            public TextureHandle TempTextureB;
            public List<int> ActiveIndices;
            public List<ScriptablePostProcessorVolume> Volumes;
            public List<ProfilingSampler> Profilers;
            public RenderingData RenderingData; // 数据结构保持不变
        }

        // 修改 Setup：接收 RenderingData 并保存
        // 注意：这里的 Setup 需要在 AddRenderPasses 中调用
        public bool Setup(ref RenderingData renderingData)
        {
            this.m_RenderingData = renderingData; // 捕获数据

            activePostProcessorIndex.Clear();
            for (int i = 0; i < postProcessors.Count; i++)
            {
                postProcessors[i].Setup();
                if (postProcessors[i].IsActive())
                {
                    activePostProcessorIndex.Add(i);
                }
            }
            return activePostProcessorIndex.Count != 0;
        }

        public override void RecordRenderGraph(RenderGraph renderGraph, ContextContainer frameData)
        {
            var resourceData = frameData.Get<UniversalResourceData>();
            var cameraData = frameData.Get<UniversalCameraData>();

            // 如果没有激活的后处理，直接跳过
            if (activePostProcessorIndex.Count == 0) return;

            // 1. 获取相机的基础描述符 (这是旧的 RenderTextureDescriptor)
            var cameraDesc = cameraData.cameraTargetDescriptor;

            // 2. 【核心修正】创建一个新的 RenderGraph 专用描述符 (TextureDesc)
            // 只有 TextureDesc 才能设置 name，也不能直接把 cameraDesc 强转过去，必须手动赋值
            var rgDesc = new TextureDesc(cameraDesc.width, cameraDesc.height);
            rgDesc.colorFormat = cameraDesc.graphicsFormat;
            rgDesc.depthBufferBits = DepthBits.None; // 后处理不需要深度
            rgDesc.msaaSamples = MSAASamples.None; // 后处理通常不需要 MSAA

            using (var builder = renderGraph.AddUnsafePass<PassData>(profilerTag, out var passData))
            {
                // 填充数据
                passData.SourceTexture = resourceData.activeColorTexture;
                passData.TargetTexture = resourceData.activeColorTexture;
                passData.ActiveIndices = activePostProcessorIndex;
                passData.Volumes = postProcessors;
                passData.Profilers = profilingSamplers;

                // 使用我们在 Setup 中缓存的旧版数据 (解决 UniversalRenderingData 找不到的问题)
                passData.RenderingData = m_RenderingData;

                // 3. 【核心修正】设置名字并创建纹理
                // 这里使用的是 rgDesc (TextureDesc 类型)，它有 name 属性
                rgDesc.name = "_TemporaryRenderTextureA";
                passData.TempTextureA = renderGraph.CreateTexture(rgDesc);

                rgDesc.name = "_TemporaryRenderTextureB";
                passData.TempTextureB = renderGraph.CreateTexture(rgDesc);

                // 声明依赖关系 (保持不变)
                builder.UseTexture(passData.SourceTexture, AccessFlags.Read);
                builder.UseTexture(passData.TempTextureA, AccessFlags.ReadWrite);
                builder.UseTexture(passData.TempTextureB, AccessFlags.ReadWrite);
                builder.UseTexture(passData.TargetTexture, AccessFlags.ReadWrite);

                // 设置执行逻辑 (保持不变)
                builder.SetRenderFunc((PassData data, UnsafeGraphContext context) =>
                {
                    var cmd = CommandBufferHelpers.GetNativeCommandBuffer(context.cmd);

                    var source = data.SourceTexture;
                    var target = data.TargetTexture;
                    var tempA = data.TempTextureA;
                    var tempB = data.TempTextureB;

                    if (data.ActiveIndices.Count == 1)
                    {
                        int index = data.ActiveIndices[0];
                        using (new ProfilingScope(cmd, data.Profilers[index]))
                        {
                            data.Volumes[index].Render(cmd, ref data.RenderingData, source, tempA);
                        }

                        Blitter.BlitCameraTexture(cmd, tempA, target);
                    }
                    else
                    {
                        Blitter.BlitCameraTexture(cmd, source, tempA);
                        var currSource = tempA;
                        var currDest = tempB;

                        foreach (int index in data.ActiveIndices)
                        {
                            var postProcessor = data.Volumes[index];
                            using (new ProfilingScope(cmd, data.Profilers[index]))
                            {
                                postProcessor.Render(cmd, ref data.RenderingData, currSource, currDest);
                            }

                            CoreUtils.Swap(ref currSource, ref currDest);
                        }

                        Blitter.BlitCameraTexture(cmd, currSource, target);
                    }
                });
            }
        }
    }
}