using System.Collections.Generic;
using RebootKit.Engine.Main;
using RebootReality.jelycho.Main;
using Unity.Mathematics;
using UnityEngine;
using UnityEngine.Experimental.Rendering;
using UnityEngine.Rendering;
using UnityEngine.Rendering.RendererUtils;
using UnityEngine.Rendering.RenderGraphModule;
using UnityEngine.Rendering.RenderGraphModule.Util;
using UnityEngine.Rendering.Universal;

namespace RebootReality.jelycho.InfectedArea {
    class InfectedAreaRenderPass : ScriptableRenderPass {
        const string k_InfectedTextureName = "_InfectedTexture";
        const string k_InfectedRenderPass = "InfectedRenderPass";
        const string k_CompositeInfectedRenderPass = "CompositeInfectedRenderPass";

        class MainPassData {
            internal List<InfectedAreaInfo> Areas;

            internal Material Material;
            internal int PassIndex;
        }

        class CompositePassData {
            internal Material Material;
            internal int PassIndex;

            internal TextureHandle FrameTexture;
            internal TextureHandle InfectedTexture;
        }

        static MaterialPropertyBlock s_SharedPropertyBlock = new MaterialPropertyBlock();

        static readonly int s_Center = Shader.PropertyToID("_Center");
        static readonly int s_Radius = Shader.PropertyToID("_Radius");
        static readonly int s_FrameTexture = Shader.PropertyToID("_FrameTexture");
        static readonly int s_InfectedTexture = Shader.PropertyToID("_InfectedTexture");

        Material m_Material;
        Material m_CompositeMaterial;
        Shader m_StencilShader;

        public InfectedAreaRenderPass(Material material, Material compositeMaterial) {
            m_Material = material;
            m_CompositeMaterial = compositeMaterial;
        }

        public override void RecordRenderGraph(RenderGraph renderGraph, ContextContainer frameData) {
            if (RR.World == null || RR.World.Context is not WorldContext worldContext) {
                return;
            }

            UniversalResourceData resourceData = frameData.Get<UniversalResourceData>();
            UniversalCameraData cameraData = frameData.Get<UniversalCameraData>();

            if (resourceData.isActiveTargetBackBuffer) {
                return;
            }

            TextureHandle source = resourceData.activeColorTexture;

            TextureDesc infectedTextureDesc = resourceData.activeColorTexture.GetDescriptor(renderGraph);
            infectedTextureDesc.name = "InfectedColor";
            infectedTextureDesc.colorFormat = GraphicsFormat.R8G8B8A8_SRGB;
            TextureHandle infectedColorTexture = renderGraph.CreateTexture(infectedTextureDesc);

            TextureDesc finalTextureDesc = resourceData.activeColorTexture.GetDescriptor(renderGraph);
            finalTextureDesc.name = "InfectedCombined";
            TextureHandle finalColorTexture = renderGraph.CreateTexture(finalTextureDesc);

            if (!source.IsValid() || !infectedColorTexture.IsValid() || !finalColorTexture.IsValid()) {
                return;
            }

            using (IRasterRenderGraphBuilder builder = renderGraph.AddRasterRenderPass(passName,
                                                                                       out MainPassData passData,
                                                                                       profilingSampler)) {

                passData.Material = m_Material;
                passData.PassIndex = 0;
                passData.Areas = worldContext.InfectedAreaManager.InfectedAreas;
                
                builder.SetRenderAttachment(infectedColorTexture, 0, AccessFlags.Write);
                builder.SetRenderAttachmentDepth(resourceData.activeDepthTexture, AccessFlags.Write);

                builder.SetRenderFunc((MainPassData data, RasterGraphContext rgContext) => {
                    s_SharedPropertyBlock.Clear();
 
                    foreach (InfectedAreaInfo infectedAreaInfo in data.Areas) {
                        s_SharedPropertyBlock.SetVector(s_Center, infectedAreaInfo.Center.xyzz);
                        s_SharedPropertyBlock.SetFloat(s_Radius, infectedAreaInfo.Radius);

                        rgContext.cmd.DrawProcedural(Matrix4x4.identity,
                                                     data.Material,
                                                     data.PassIndex,
                                                     MeshTopology.Triangles,
                                                     3,
                                                     1,
                                                     s_SharedPropertyBlock);
                    }
                });
            }

            using (IRasterRenderGraphBuilder builder = renderGraph.AddRasterRenderPass(passName + " Composite",
                                                                                       out CompositePassData passData,
                                                                                       profilingSampler)) {

                passData.Material = m_CompositeMaterial;
                passData.PassIndex = 0;
                passData.FrameTexture = resourceData.activeColorTexture;
                passData.InfectedTexture = infectedColorTexture;

                builder.UseTexture(passData.FrameTexture, AccessFlags.Read);
                builder.UseTexture(passData.InfectedTexture, AccessFlags.Read);
                builder.SetRenderAttachment(finalColorTexture, 0, AccessFlags.Write);

                builder.SetRenderFunc((CompositePassData data, RasterGraphContext rgContext) => {
                    s_SharedPropertyBlock.Clear();
                    s_SharedPropertyBlock.SetTexture(s_FrameTexture, data.FrameTexture);
                    s_SharedPropertyBlock.SetTexture(s_InfectedTexture, data.InfectedTexture);

                    rgContext.cmd.DrawProcedural(Matrix4x4.identity,
                                                 data.Material,
                                                 data.PassIndex,
                                                 MeshTopology.Triangles,
                                                 3,
                                                 1,
                                                 s_SharedPropertyBlock);
                });
            }

            resourceData.cameraColor = finalColorTexture;
        }
    }

    public class InfectedAreaRendererFeature : ScriptableRendererFeature {
        [SerializeField] Material m_Material;
        [SerializeField] Material m_CompositeMaterial;

        InfectedAreaRenderPass m_InfectedAreaRenderPass;

        public override void Create() {
            m_InfectedAreaRenderPass = new InfectedAreaRenderPass(m_Material, m_CompositeMaterial) {
                renderPassEvent = RenderPassEvent.BeforeRenderingTransparents
            };
        }

        protected override void Dispose(bool disposing) { }

        public override void AddRenderPasses(ScriptableRenderer renderer, ref RenderingData renderingData) {
            if (m_InfectedAreaRenderPass == null) {
                return;
            }

            if (renderingData.cameraData.cameraType == CameraType.Game) {
                renderer.EnqueuePass(m_InfectedAreaRenderPass);
            }
        }
    }
}