//
// Created by atdunbg on 2026/9/23.
//

#include <Engine/Renderer/Passes/SkyboxPass.h>
#include <Engine/Renderer/Cubemap.h>
#include <Engine/Vulkan/Device.h>
#include <Engine/Vulkan/DescriptorManager.h>
#include <Engine/Vulkan/ShaderManager.h>
#include <Engine/Core/Log.h>

#include <glm/glm.hpp>

#include <tracy/Tracy.hpp>

#include <array>

namespace Engine::Passes
{
    SkyboxPass::SkyboxPass(Device& device, ShaderManager& shaders,
                           DescriptorManager& descriptors, FrameSceneData& frame,
                           RG::TextureHandle hdrColor, const Cubemap* env)
        : m_Device(device), m_Descriptors(descriptors), m_Frame(frame),
          m_HDRColor(hdrColor), m_Env(env)
    {
        // Set0 = {samplerCube}（fragment 采样）
        std::vector<DescriptorBinding> bindings = {
            {0, vk::DescriptorType::eCombinedImageSampler,
             vk::ShaderStageFlagBits::eFragment},
        };
        m_SetLayout = descriptors.CreateLayout(bindings);

        // push = invVP 64B（skybox.vert/.frag 声明一致，VUID-08878）
        m_Layout = descriptors.CreatePipelineLayout(
            std::vector<vk::DescriptorSetLayout>{m_SetLayout},
            sizeof(glm::mat4));

        const std::string shaderDir = "shaders/";
        auto vert = shaders.CreateFromFile(
            shaderDir + "skybox.vert.spv",
            vk::ShaderStageFlagBits::eVertex,
            std::vector<vk::DescriptorSetLayout>{m_SetLayout},
            sizeof(glm::mat4));
        auto frag = shaders.CreateFromFile(
            shaderDir + "skybox.frag.spv",
            vk::ShaderStageFlagBits::eFragment,
            std::vector<vk::DescriptorSetLayout>{m_SetLayout},
            sizeof(glm::mat4));

        m_Vert = vert.Handle;
        m_Frag = frag.Handle;
        if (!m_Vert || !m_Frag) {
            ENGINE_FATAL("SkyboxPass: failed to create shader objects");
        }

        // per-slot set：cube view 全程稳定，构造期绑定一次即可
        for (u32 slot = 0; slot < kMaxFramesInFlight; ++slot) {
            m_Sets[slot] = descriptors.AllocateDescriptorSet(m_SetLayout);
            if (m_Env) {
                descriptors.UpdateTexture(m_Sets[slot], 0,
                                          m_Env->GetSampler(),
                                          m_Env->GetView());
            }
        }
    }

    SkyboxPass::~SkyboxPass()
    {
        const auto& vkDevice = m_Device.GetDevice();

        if (m_Vert) vkDevice.destroyShaderEXT(m_Vert);
        if (m_Frag) vkDevice.destroyShaderEXT(m_Frag);
        vkDevice.destroyPipelineLayout(m_Layout);
        vkDevice.destroyDescriptorSetLayout(m_SetLayout);
    }

    void SkyboxPass::OnEnvironmentChanged(const Cubemap* env)
    {
        m_Env = env;
        if (!m_Env) return;

        // cube view 全程稳定语义是"单个环境内"；切换环境 = 新 view，
        // per-slot set 全部重绑
        for (u32 slot = 0; slot < kMaxFramesInFlight; ++slot) {
            m_Descriptors.UpdateTexture(m_Sets[slot], 0,
                                        m_Env->GetSampler(),
                                        m_Env->GetView());
        }
    }

    void SkyboxPass::Register(RG::RenderGraph& rg)
    {
        rg.AddPass("Skybox", [this](RG::RenderGraphContext& ctx) {
            ZoneScopedN("Skybox");
            const vk::CommandBuffer cmd = ctx.cmd;

            vk::ClearValue clear;
            clear.color = vk::ClearColorValue(
                std::array<float, 4>{0.1f, 0.1f, 0.1f, 1.0f});

            vk::RenderingAttachmentInfo color;
            color.setImageView(ctx.View(m_HDRColor))
                 .setImageLayout(vk::ImageLayout::eColorAttachmentOptimal)
                 .setLoadOp(vk::AttachmentLoadOp::eClear)   // 清屏职责在本 pass
                 .setStoreOp(vk::AttachmentStoreOp::eStore)
                 .setClearValue(clear);

            vk::RenderingInfo renderingInfo;
            renderingInfo.setRenderArea({{0, 0}, ctx.extent})
                         .setLayerCount(1)
                         .setColorAttachments(color);   // 无深度附件

            cmd.beginRendering(renderingInfo);

            if (m_Env) {
                // 无环境贴图：只清屏（Forward loadOp=Load 依赖这里先写）
                std::array<vk::ShaderStageFlagBits, 2> stages = {
                    vk::ShaderStageFlagBits::eVertex,
                    vk::ShaderStageFlagBits::eFragment
                };
                std::array<vk::ShaderEXT, 2> shaders = {m_Vert, m_Frag};
                cmd.bindShadersEXT(stages, shaders);

                cmd.bindDescriptorSets(vk::PipelineBindPoint::eGraphics,
                                       m_Layout, 0,
                                       m_Sets[ctx.frame.frameSlot], {});
                cmd.pushConstants<glm::mat4>(
                    m_Layout,
                    vk::ShaderStageFlagBits::eVertex |
                    vk::ShaderStageFlagBits::eFragment,
                    0, m_Frame.skyInvVP);

                // ---- 动态状态 ----
                cmd.setRasterizerDiscardEnable(VK_FALSE);

                cmd.setDepthTestEnable(VK_FALSE);
                cmd.setDepthWriteEnable(VK_FALSE);
                cmd.setDepthBoundsTestEnable(VK_FALSE);
                cmd.setStencilTestEnable(VK_FALSE);
                cmd.setDepthBiasEnable(VK_FALSE);

                cmd.setPolygonModeEXT(vk::PolygonMode::eFill);
                cmd.setCullMode(vk::CullModeFlagBits::eNone);
                cmd.setFrontFace(vk::FrontFace::eCounterClockwise);
                cmd.setPrimitiveTopology(vk::PrimitiveTopology::eTriangleList);
                cmd.setPrimitiveRestartEnable(VK_FALSE);

                // 全屏三角：无顶点输入
                cmd.setVertexInputEXT({}, {});

                cmd.setRasterizationSamplesEXT(vk::SampleCountFlagBits::e1);
                vk::SampleMask sampleMask = 0xFFFFFFFF;
                cmd.setSampleMaskEXT(vk::SampleCountFlagBits::e1, sampleMask);
                cmd.setAlphaToCoverageEnableEXT(VK_FALSE);
                cmd.setAlphaToOneEnableEXT(VK_FALSE);

                vk::Viewport viewport(0.0f, 0.0f,
                                      static_cast<float>(ctx.extent.width),
                                      static_cast<float>(ctx.extent.height),
                                      0.0f, 1.0f);
                cmd.setViewportWithCount(viewport);
                cmd.setScissorWithCount(vk::Rect2D({0, 0}, ctx.extent));

                // 无混合直写（天空不透明）
                vk::ColorBlendEquationEXT blendEquation;
                blendEquation.setSrcColorBlendFactor(vk::BlendFactor::eOne)
                             .setDstColorBlendFactor(vk::BlendFactor::eZero)
                             .setColorBlendOp(vk::BlendOp::eAdd)
                             .setSrcAlphaBlendFactor(vk::BlendFactor::eOne)
                             .setDstAlphaBlendFactor(vk::BlendFactor::eZero)
                             .setAlphaBlendOp(vk::BlendOp::eAdd);
                // ArrayProxyNoTemporaries 拒绝临时量：具名局部变量传入
                vk::Bool32 blendEnable = VK_FALSE;
                vk::ColorComponentFlags colorWriteMask =
                    vk::ColorComponentFlagBits::eR |
                    vk::ColorComponentFlagBits::eG |
                    vk::ColorComponentFlagBits::eB |
                    vk::ColorComponentFlagBits::eA;
                cmd.setColorBlendEnableEXT(0, blendEnable);
                cmd.setColorBlendEquationEXT(0, blendEquation);
                cmd.setColorWriteMaskEXT(0, colorWriteMask);

                cmd.draw(3, 1, 0, 0);
            }

            cmd.endRendering();
        })
        .Write(m_HDRColor, RG::ResourceUse::ColorAttachment);
    }

} // namespace Engine::Passes