#include <gtest/gtest.h>
#include <XCEngine/Core/Asset/AssetDatabase.h>
#include <XCEngine/Resources/BuiltinResources.h>
#include <XCEngine/Core/Asset/ResourceManager.h>
#include <XCEngine/Resources/Shader/ShaderLoader.h>
#include <XCEngine/Core/Asset/ResourceTypes.h>
#include <XCEngine/Core/Containers/Array.h>

#include <chrono>
#include <cstdio>
#include <filesystem>
#include <fstream>
#include <thread>

using namespace XCEngine::Resources;
using namespace XCEngine::Containers;

namespace {

void WriteTextFile(const std::filesystem::path& path, const std::string& contents) {
    std::ofstream output(path, std::ios::binary | std::ios::trunc);
    ASSERT_TRUE(output.is_open());
    output << contents;
    ASSERT_TRUE(static_cast<bool>(output));
}

TEST(ShaderLoader, GetResourceType) {
    ShaderLoader loader;
    EXPECT_EQ(loader.GetResourceType(), ResourceType::Shader);
}

TEST(ShaderLoader, GetSupportedExtensions) {
    ShaderLoader loader;
    auto extensions = loader.GetSupportedExtensions();
    EXPECT_GE(extensions.Size(), 1u);
}

TEST(ShaderLoader, CanLoad) {
    ShaderLoader loader;
    EXPECT_TRUE(loader.CanLoad("test.vert"));
    EXPECT_TRUE(loader.CanLoad("test.frag"));
    EXPECT_TRUE(loader.CanLoad("test.glsl"));
    EXPECT_TRUE(loader.CanLoad("test.hlsl"));
    EXPECT_TRUE(loader.CanLoad("test.xcshader"));
    EXPECT_TRUE(loader.CanLoad(GetBuiltinForwardLitShaderPath()));
    EXPECT_TRUE(loader.CanLoad(GetBuiltinUnlitShaderPath()));
    EXPECT_TRUE(loader.CanLoad(GetBuiltinObjectIdShaderPath()));
    EXPECT_FALSE(loader.CanLoad("test.txt"));
    EXPECT_FALSE(loader.CanLoad("test.png"));
}

TEST(ShaderLoader, LoadInvalidPath) {
    ShaderLoader loader;
    LoadResult result = loader.Load("invalid/path/shader.glsl");
    EXPECT_FALSE(result);
}

TEST(ShaderLoader, LoadLegacySingleStageShaderBuildsDefaultPassVariant) {
    namespace fs = std::filesystem;

    const fs::path shaderPath = fs::temp_directory_path() / "xc_shader_loader_stage.vert";
    {
        std::ofstream shaderFile(shaderPath);
        ASSERT_TRUE(shaderFile.is_open());
        shaderFile << "#version 430\nvoid main() {}";
    }

    ShaderLoader loader;
    LoadResult result = loader.Load(shaderPath.string().c_str());
    ASSERT_TRUE(result);
    ASSERT_NE(result.resource, nullptr);

    Shader* shader = static_cast<Shader*>(result.resource);
    ASSERT_NE(shader, nullptr);
    EXPECT_EQ(shader->GetShaderType(), ShaderType::Vertex);
    ASSERT_EQ(shader->GetPassCount(), 1u);

    const ShaderPass* pass = shader->FindPass("Default");
    ASSERT_NE(pass, nullptr);
    ASSERT_EQ(pass->variants.Size(), 1u);
    EXPECT_EQ(pass->variants[0].stage, ShaderType::Vertex);
    EXPECT_EQ(pass->variants[0].backend, ShaderBackend::Generic);
    EXPECT_EQ(pass->variants[0].sourceCode, shader->GetSourceCode());

    delete shader;
    std::remove(shaderPath.string().c_str());
}

TEST(ShaderLoader, LoadShaderManifestBuildsMultiPassBackendVariants) {
    namespace fs = std::filesystem;

    const fs::path shaderRoot = fs::temp_directory_path() / "xc_shader_manifest_test";
    const fs::path stageRoot = shaderRoot / "stages";
    const fs::path manifestPath = shaderRoot / "multi_pass.shader";

    fs::remove_all(shaderRoot);
    fs::create_directories(stageRoot);

    WriteTextFile(stageRoot / "forward_lit.vs.hlsl", "float4 MainVS() : SV_POSITION { return 0; } // FORWARD_LIT_D3D12_VS\n");
    WriteTextFile(stageRoot / "forward_lit.ps.hlsl", "float4 MainPS() : SV_TARGET { return 1; } // FORWARD_LIT_D3D12_PS\n");
    WriteTextFile(stageRoot / "forward_lit.vert.glsl", "#version 430\n// FORWARD_LIT_GL_VS\nvoid main() {}\n");
    WriteTextFile(stageRoot / "forward_lit.frag.glsl", "#version 430\n// FORWARD_LIT_GL_PS\nvoid main() {}\n");
    WriteTextFile(stageRoot / "forward_lit.vert.vk.glsl", "#version 450\n// FORWARD_LIT_VK_VS\nvoid main() {}\n");
    WriteTextFile(stageRoot / "forward_lit.frag.vk.glsl", "#version 450\n// FORWARD_LIT_VK_PS\nvoid main() {}\n");
    WriteTextFile(stageRoot / "depth_only.vs.hlsl", "float4 MainVS() : SV_POSITION { return 0; } // DEPTH_ONLY_D3D12_VS\n");
    WriteTextFile(stageRoot / "depth_only.ps.hlsl", "float4 MainPS() : SV_TARGET { return 1; } // DEPTH_ONLY_D3D12_PS\n");

    {
        std::ofstream manifest(manifestPath);
        ASSERT_TRUE(manifest.is_open());
        manifest << "{\n";
        manifest << "  \"name\": \"TestLitShader\",\n";
        manifest << "  \"properties\": [\n";
        manifest << "    {\n";
        manifest << "      \"name\": \"_BaseColor\",\n";
        manifest << "      \"displayName\": \"Base Color\",\n";
        manifest << "      \"type\": \"Color\",\n";
        manifest << "      \"defaultValue\": \"(1,1,1,1)\",\n";
        manifest << "      \"semantic\": \"BaseColor\"\n";
        manifest << "    },\n";
        manifest << "    {\n";
        manifest << "      \"name\": \"_MainTex\",\n";
        manifest << "      \"displayName\": \"Base Map\",\n";
        manifest << "      \"type\": \"2D\",\n";
        manifest << "      \"defaultValue\": \"white\",\n";
        manifest << "      \"semantic\": \"BaseColorTexture\"\n";
        manifest << "    }\n";
        manifest << "  ],\n";
        manifest << "  \"passes\": [\n";
        manifest << "    {\n";
        manifest << "      \"name\": \"ForwardLit\",\n";
        manifest << "      \"tags\": {\n";
        manifest << "        \"LightMode\": \"ForwardBase\",\n";
        manifest << "        \"Queue\": \"Geometry\"\n";
        manifest << "      },\n";
        manifest << "      \"resources\": [\n";
        manifest << "        { \"name\": \"PerObjectConstants\", \"type\": \"ConstantBuffer\", \"set\": 1, \"binding\": 0, \"semantic\": \"PerObject\" },\n";
        manifest << "        { \"name\": \"MaterialConstants\", \"type\": \"ConstantBuffer\", \"set\": 2, \"binding\": 0, \"semantic\": \"Material\" },\n";
        manifest << "        { \"name\": \"BaseColorTexture\", \"type\": \"Texture2D\", \"set\": 3, \"binding\": 0, \"semantic\": \"BaseColorTexture\" },\n";
        manifest << "        { \"name\": \"LinearClampSampler\", \"type\": \"Sampler\", \"set\": 4, \"binding\": 0, \"semantic\": \"LinearClampSampler\" }\n";
        manifest << "      ],\n";
        manifest << "      \"variants\": [\n";
        manifest << "        { \"stage\": \"Vertex\", \"backend\": \"D3D12\", \"language\": \"HLSL\", \"source\": \"stages/forward_lit.vs.hlsl\", \"entryPoint\": \"MainVS\", \"profile\": \"vs_5_0\" },\n";
        manifest << "        { \"stage\": \"Fragment\", \"backend\": \"D3D12\", \"language\": \"HLSL\", \"source\": \"stages/forward_lit.ps.hlsl\", \"entryPoint\": \"MainPS\", \"profile\": \"ps_5_0\" },\n";
        manifest << "        { \"stage\": \"Vertex\", \"backend\": \"OpenGL\", \"language\": \"GLSL\", \"source\": \"stages/forward_lit.vert.glsl\" },\n";
        manifest << "        { \"stage\": \"Fragment\", \"backend\": \"OpenGL\", \"language\": \"GLSL\", \"source\": \"stages/forward_lit.frag.glsl\" },\n";
        manifest << "        { \"stage\": \"Vertex\", \"backend\": \"Vulkan\", \"language\": \"GLSL\", \"source\": \"stages/forward_lit.vert.vk.glsl\" },\n";
        manifest << "        { \"stage\": \"Fragment\", \"backend\": \"Vulkan\", \"language\": \"GLSL\", \"source\": \"stages/forward_lit.frag.vk.glsl\" }\n";
        manifest << "      ]\n";
        manifest << "    },\n";
        manifest << "    {\n";
        manifest << "      \"name\": \"DepthOnly\",\n";
        manifest << "      \"tags\": {\n";
        manifest << "        \"LightMode\": \"DepthOnly\"\n";
        manifest << "      },\n";
        manifest << "      \"variants\": [\n";
        manifest << "        { \"stage\": \"Vertex\", \"backend\": \"D3D12\", \"language\": \"HLSL\", \"source\": \"stages/depth_only.vs.hlsl\" },\n";
        manifest << "        { \"stage\": \"Fragment\", \"backend\": \"D3D12\", \"language\": \"HLSL\", \"source\": \"stages/depth_only.ps.hlsl\" }\n";
        manifest << "      ]\n";
        manifest << "    }\n";
        manifest << "  ]\n";
        manifest << "}\n";
    }

    ShaderLoader loader;
    LoadResult result = loader.Load(manifestPath.string().c_str());
    ASSERT_TRUE(result);
    ASSERT_NE(result.resource, nullptr);

    Shader* shader = static_cast<Shader*>(result.resource);
    ASSERT_NE(shader, nullptr);
    ASSERT_TRUE(shader->IsValid());
    EXPECT_EQ(shader->GetName(), "TestLitShader");
    ASSERT_EQ(shader->GetProperties().Size(), 2u);
    ASSERT_EQ(shader->GetPassCount(), 2u);

    const ShaderPropertyDesc* baseColorProperty = shader->FindProperty("_BaseColor");
    ASSERT_NE(baseColorProperty, nullptr);
    EXPECT_EQ(baseColorProperty->displayName, "Base Color");
    EXPECT_EQ(baseColorProperty->type, ShaderPropertyType::Color);
    EXPECT_EQ(baseColorProperty->defaultValue, "(1,1,1,1)");
    EXPECT_EQ(baseColorProperty->semantic, "BaseColor");

    const ShaderPropertyDesc* baseMapProperty = shader->FindProperty("_MainTex");
    ASSERT_NE(baseMapProperty, nullptr);
    EXPECT_EQ(baseMapProperty->type, ShaderPropertyType::Texture2D);
    EXPECT_EQ(baseMapProperty->defaultValue, "white");
    EXPECT_EQ(baseMapProperty->semantic, "BaseColorTexture");

    const ShaderPass* forwardLitPass = shader->FindPass("ForwardLit");
    ASSERT_NE(forwardLitPass, nullptr);
    ASSERT_EQ(forwardLitPass->tags.Size(), 2u);
    ASSERT_EQ(forwardLitPass->resources.Size(), 4u);
    EXPECT_EQ(forwardLitPass->tags[0].name, "LightMode");
    EXPECT_EQ(forwardLitPass->tags[0].value, "ForwardBase");
    EXPECT_EQ(forwardLitPass->tags[1].name, "Queue");
    EXPECT_EQ(forwardLitPass->tags[1].value, "Geometry");

    const ShaderResourceBindingDesc* baseTextureBinding =
        shader->FindPassResourceBinding("ForwardLit", "BaseColorTexture");
    ASSERT_NE(baseTextureBinding, nullptr);
    EXPECT_EQ(baseTextureBinding->type, ShaderResourceType::Texture2D);
    EXPECT_EQ(baseTextureBinding->set, 3u);
    EXPECT_EQ(baseTextureBinding->binding, 0u);
    EXPECT_EQ(baseTextureBinding->semantic, "BaseColorTexture");

    const ShaderStageVariant* d3d12Vertex = shader->FindVariant("ForwardLit", ShaderType::Vertex, ShaderBackend::D3D12);
    ASSERT_NE(d3d12Vertex, nullptr);
    EXPECT_EQ(d3d12Vertex->entryPoint, "MainVS");
    EXPECT_EQ(d3d12Vertex->profile, "vs_5_0");
    EXPECT_NE(std::string(d3d12Vertex->sourceCode.CStr()).find("FORWARD_LIT_D3D12_VS"), std::string::npos);

    const ShaderStageVariant* openglFragment = shader->FindVariant("ForwardLit", ShaderType::Fragment, ShaderBackend::OpenGL);
    ASSERT_NE(openglFragment, nullptr);
    EXPECT_EQ(openglFragment->entryPoint, "main");
    EXPECT_EQ(openglFragment->profile, "fs_4_30");
    EXPECT_NE(std::string(openglFragment->sourceCode.CStr()).find("FORWARD_LIT_GL_PS"), std::string::npos);

    const ShaderStageVariant* vulkanFragment = shader->FindVariant("ForwardLit", ShaderType::Fragment, ShaderBackend::Vulkan);
    ASSERT_NE(vulkanFragment, nullptr);
    EXPECT_EQ(vulkanFragment->profile, "fs_4_50");
    EXPECT_NE(std::string(vulkanFragment->sourceCode.CStr()).find("FORWARD_LIT_VK_PS"), std::string::npos);

    const ShaderPass* depthOnlyPass = shader->FindPass("DepthOnly");
    ASSERT_NE(depthOnlyPass, nullptr);
    ASSERT_EQ(depthOnlyPass->tags.Size(), 1u);
    EXPECT_EQ(depthOnlyPass->tags[0].value, "DepthOnly");
    EXPECT_NE(shader->FindVariant("DepthOnly", ShaderType::Vertex, ShaderBackend::D3D12), nullptr);
    EXPECT_NE(shader->FindVariant("DepthOnly", ShaderType::Fragment, ShaderBackend::D3D12), nullptr);
    EXPECT_EQ(shader->FindVariant("DepthOnly", ShaderType::Fragment, ShaderBackend::OpenGL), nullptr);

    delete shader;
    fs::remove_all(shaderRoot);
}

TEST(ShaderLoader, LoadUnityLikeShaderAuthoringBuildsRuntimeContract) {
    namespace fs = std::filesystem;

    const fs::path shaderRoot = fs::temp_directory_path() / "xc_shader_authoring_test";
    const fs::path stageRoot = shaderRoot / "stages";
    const fs::path shaderPath = shaderRoot / "multi_pass.shader";

    fs::remove_all(shaderRoot);
    fs::create_directories(stageRoot);

    WriteTextFile(stageRoot / "forward_lit.vs.hlsl", "float4 MainVS() : SV_POSITION { return 0; } // AUTHORING_FORWARD_LIT_D3D12_VS\n");
    WriteTextFile(stageRoot / "forward_lit.ps.hlsl", "float4 MainPS() : SV_TARGET { return 1; } // AUTHORING_FORWARD_LIT_D3D12_PS\n");
    WriteTextFile(stageRoot / "forward_lit.vert.glsl", "#version 430\n// AUTHORING_FORWARD_LIT_GL_VS\nvoid main() {}\n");
    WriteTextFile(stageRoot / "forward_lit.frag.glsl", "#version 430\n// AUTHORING_FORWARD_LIT_GL_PS\nvoid main() {}\n");
    WriteTextFile(stageRoot / "forward_lit.vert.vk.glsl", "#version 450\n// AUTHORING_FORWARD_LIT_VK_VS\nvoid main() {}\n");
    WriteTextFile(stageRoot / "forward_lit.frag.vk.glsl", "#version 450\n// AUTHORING_FORWARD_LIT_VK_PS\nvoid main() {}\n");
    WriteTextFile(stageRoot / "depth_only.vs.hlsl", "float4 MainVS() : SV_POSITION { return 0; } // AUTHORING_DEPTH_ONLY_D3D12_VS\n");
    WriteTextFile(stageRoot / "depth_only.ps.hlsl", "float4 MainPS() : SV_TARGET { return 1; } // AUTHORING_DEPTH_ONLY_D3D12_PS\n");

    WriteTextFile(
        shaderPath,
        R"(Shader "AuthoringLit"
{
    Properties
    {
        _BaseColor ("Base Color", Color) = (1,1,1,1) [Semantic(BaseColor)]
        _MainTex ("Base Map", 2D) = "white" [Semantic(BaseColorTexture)]
    }
    SubShader
    {
        Tags { "Queue" = "Geometry" }
        Pass
        {
            Name "ForwardLit"
            Tags { "LightMode" = "ForwardBase" }
            Resources
            {
                PerObjectConstants (ConstantBuffer, 1, 0) [Semantic(PerObject)]
                MaterialConstants (ConstantBuffer, 2, 0) [Semantic(Material)]
                BaseColorTexture (Texture2D, 3, 0) [Semantic(BaseColorTexture)]
                LinearClampSampler (Sampler, 4, 0) [Semantic(LinearClampSampler)]
            }
            HLSLPROGRAM
            #pragma vertex MainVS
            #pragma fragment MainPS
            #pragma backend D3D12 HLSL "stages/forward_lit.vs.hlsl" "stages/forward_lit.ps.hlsl" vs_5_0 ps_5_0
            #pragma backend OpenGL GLSL "stages/forward_lit.vert.glsl" "stages/forward_lit.frag.glsl"
            #pragma backend Vulkan GLSL "stages/forward_lit.vert.vk.glsl" "stages/forward_lit.frag.vk.glsl"
            ENDHLSL
        }
        Pass
        {
            Name "DepthOnly"
            Tags { "LightMode" = "DepthOnly" }
            HLSLPROGRAM
            #pragma vertex MainVS
            #pragma fragment MainPS
            #pragma backend D3D12 HLSL "stages/depth_only.vs.hlsl" "stages/depth_only.ps.hlsl"
            ENDHLSL
        }
    }
}
)");

    ShaderLoader loader;
    LoadResult result = loader.Load(shaderPath.string().c_str());
    ASSERT_TRUE(result);
    ASSERT_NE(result.resource, nullptr);

    Shader* shader = static_cast<Shader*>(result.resource);
    ASSERT_NE(shader, nullptr);
    ASSERT_TRUE(shader->IsValid());
    EXPECT_EQ(shader->GetName(), "AuthoringLit");
    ASSERT_EQ(shader->GetProperties().Size(), 2u);
    ASSERT_EQ(shader->GetPassCount(), 2u);

    const ShaderPropertyDesc* baseColorProperty = shader->FindProperty("_BaseColor");
    ASSERT_NE(baseColorProperty, nullptr);
    EXPECT_EQ(baseColorProperty->displayName, "Base Color");
    EXPECT_EQ(baseColorProperty->type, ShaderPropertyType::Color);
    EXPECT_EQ(baseColorProperty->defaultValue, "(1,1,1,1)");
    EXPECT_EQ(baseColorProperty->semantic, "BaseColor");

    const ShaderPropertyDesc* baseMapProperty = shader->FindProperty("_MainTex");
    ASSERT_NE(baseMapProperty, nullptr);
    EXPECT_EQ(baseMapProperty->type, ShaderPropertyType::Texture2D);
    EXPECT_EQ(baseMapProperty->defaultValue, "white");
    EXPECT_EQ(baseMapProperty->semantic, "BaseColorTexture");

    const ShaderPass* forwardLitPass = shader->FindPass("ForwardLit");
    ASSERT_NE(forwardLitPass, nullptr);
    ASSERT_EQ(forwardLitPass->tags.Size(), 2u);
    ASSERT_EQ(forwardLitPass->resources.Size(), 4u);
    EXPECT_EQ(forwardLitPass->tags[0].name, "Queue");
    EXPECT_EQ(forwardLitPass->tags[0].value, "Geometry");
    EXPECT_EQ(forwardLitPass->tags[1].name, "LightMode");
    EXPECT_EQ(forwardLitPass->tags[1].value, "ForwardBase");

    const ShaderResourceBindingDesc* baseTextureBinding =
        shader->FindPassResourceBinding("ForwardLit", "BaseColorTexture");
    ASSERT_NE(baseTextureBinding, nullptr);
    EXPECT_EQ(baseTextureBinding->type, ShaderResourceType::Texture2D);
    EXPECT_EQ(baseTextureBinding->set, 3u);
    EXPECT_EQ(baseTextureBinding->binding, 0u);
    EXPECT_EQ(baseTextureBinding->semantic, "BaseColorTexture");

    const ShaderStageVariant* d3d12Vertex =
        shader->FindVariant("ForwardLit", ShaderType::Vertex, ShaderBackend::D3D12);
    ASSERT_NE(d3d12Vertex, nullptr);
    EXPECT_EQ(d3d12Vertex->entryPoint, "MainVS");
    EXPECT_EQ(d3d12Vertex->profile, "vs_5_0");
    EXPECT_NE(std::string(d3d12Vertex->sourceCode.CStr()).find("AUTHORING_FORWARD_LIT_D3D12_VS"), std::string::npos);

    const ShaderStageVariant* openglFragment =
        shader->FindVariant("ForwardLit", ShaderType::Fragment, ShaderBackend::OpenGL);
    ASSERT_NE(openglFragment, nullptr);
    EXPECT_EQ(openglFragment->entryPoint, "MainPS");
    EXPECT_EQ(openglFragment->profile, "fs_4_30");
    EXPECT_NE(std::string(openglFragment->sourceCode.CStr()).find("AUTHORING_FORWARD_LIT_GL_PS"), std::string::npos);

    const ShaderStageVariant* vulkanFragment =
        shader->FindVariant("ForwardLit", ShaderType::Fragment, ShaderBackend::Vulkan);
    ASSERT_NE(vulkanFragment, nullptr);
    EXPECT_EQ(vulkanFragment->profile, "fs_4_50");
    EXPECT_NE(std::string(vulkanFragment->sourceCode.CStr()).find("AUTHORING_FORWARD_LIT_VK_PS"), std::string::npos);

    const ShaderPass* depthOnlyPass = shader->FindPass("DepthOnly");
    ASSERT_NE(depthOnlyPass, nullptr);
    ASSERT_EQ(depthOnlyPass->tags.Size(), 2u);
    EXPECT_EQ(depthOnlyPass->tags[0].name, "Queue");
    EXPECT_EQ(depthOnlyPass->tags[0].value, "Geometry");
    EXPECT_EQ(depthOnlyPass->tags[1].name, "LightMode");
    EXPECT_EQ(depthOnlyPass->tags[1].value, "DepthOnly");
    EXPECT_NE(shader->FindVariant("DepthOnly", ShaderType::Vertex, ShaderBackend::D3D12), nullptr);
    EXPECT_NE(shader->FindVariant("DepthOnly", ShaderType::Fragment, ShaderBackend::D3D12), nullptr);

    delete shader;
    fs::remove_all(shaderRoot);
}

TEST(ShaderLoader, ResourceManagerLoadsShaderManifestRelativeToResourceRoot) {
    namespace fs = std::filesystem;

    ResourceManager& manager = ResourceManager::Get();
    manager.Initialize();

    const fs::path previousPath = fs::current_path();
    const fs::path projectRoot = fs::temp_directory_path() / "xc_shader_manifest_resource_root";
    const fs::path shaderDir = projectRoot / "Assets" / "Shaders";
    const fs::path manifestPath = shaderDir / "simple.shader";

    fs::remove_all(projectRoot);
    fs::create_directories(shaderDir);

    WriteTextFile(shaderDir / "simple.vert.glsl", "#version 430\n// SIMPLE_GL_VS\nvoid main() {}\n");
    WriteTextFile(shaderDir / "simple.frag.glsl", "#version 430\n// SIMPLE_GL_PS\nvoid main() {}\n");

    {
        std::ofstream manifest(manifestPath);
        ASSERT_TRUE(manifest.is_open());
        manifest << "{\n";
        manifest << "  \"name\": \"SimpleShader\",\n";
        manifest << "  \"passes\": [\n";
        manifest << "    {\n";
        manifest << "      \"name\": \"Unlit\",\n";
        manifest << "      \"tags\": { \"LightMode\": \"Unlit\" },\n";
        manifest << "      \"variants\": [\n";
        manifest << "        { \"stage\": \"Vertex\", \"backend\": \"OpenGL\", \"language\": \"GLSL\", \"source\": \"simple.vert.glsl\" },\n";
        manifest << "        { \"stage\": \"Fragment\", \"backend\": \"OpenGL\", \"language\": \"GLSL\", \"source\": \"simple.frag.glsl\" }\n";
        manifest << "      ]\n";
        manifest << "    }\n";
        manifest << "  ]\n";
        manifest << "}\n";
    }

    manager.SetResourceRoot(projectRoot.string().c_str());
    fs::current_path(projectRoot.parent_path());

    {
        const ResourceHandle<Shader> shaderHandle = manager.Load<Shader>("Assets/Shaders/simple.shader");
        ASSERT_TRUE(shaderHandle.IsValid());
        EXPECT_EQ(shaderHandle->GetName(), "SimpleShader");

        const ShaderStageVariant* vertexVariant =
            shaderHandle->FindVariant("Unlit", ShaderType::Vertex, ShaderBackend::OpenGL);
        ASSERT_NE(vertexVariant, nullptr);
        EXPECT_NE(std::string(vertexVariant->sourceCode.CStr()).find("SIMPLE_GL_VS"), std::string::npos);
    }

    fs::current_path(previousPath);
    manager.SetResourceRoot("");
    manager.Shutdown();
    fs::remove_all(projectRoot);
}

TEST(ShaderLoader, AssetDatabaseCreatesShaderArtifactAndLoaderReadsItBack) {
    namespace fs = std::filesystem;

    const fs::path projectRoot = fs::temp_directory_path() / "xc_shader_artifact_test";
    const fs::path shaderDir = projectRoot / "Assets" / "Shaders";
    const fs::path manifestPath = shaderDir / "lit.shader";

    fs::remove_all(projectRoot);
    fs::create_directories(shaderDir);

    WriteTextFile(shaderDir / "lit.vert.glsl", "#version 430\n// ARTIFACT_GL_VS\nvoid main() {}\n");
    WriteTextFile(shaderDir / "lit.frag.glsl", "#version 430\n// ARTIFACT_GL_PS\nvoid main() {}\n");

    {
        std::ofstream manifest(manifestPath);
        ASSERT_TRUE(manifest.is_open());
        manifest << "{\n";
        manifest << "  \"name\": \"ArtifactShader\",\n";
        manifest << "  \"properties\": [\n";
        manifest << "    {\n";
        manifest << "      \"name\": \"_MainTex\",\n";
        manifest << "      \"displayName\": \"Main Tex\",\n";
        manifest << "      \"type\": \"2D\",\n";
        manifest << "      \"defaultValue\": \"white\",\n";
        manifest << "      \"semantic\": \"BaseColorTexture\"\n";
        manifest << "    }\n";
        manifest << "  ],\n";
        manifest << "  \"passes\": [\n";
        manifest << "    {\n";
        manifest << "      \"name\": \"ForwardLit\",\n";
        manifest << "      \"tags\": { \"LightMode\": \"ForwardBase\" },\n";
        manifest << "      \"resources\": [\n";
        manifest << "        { \"name\": \"BaseColorTexture\", \"type\": \"Texture2D\", \"set\": 3, \"binding\": 0, \"semantic\": \"BaseColorTexture\" }\n";
        manifest << "      ],\n";
        manifest << "      \"variants\": [\n";
        manifest << "        { \"stage\": \"Vertex\", \"backend\": \"OpenGL\", \"language\": \"GLSL\", \"source\": \"lit.vert.glsl\" },\n";
        manifest << "        { \"stage\": \"Fragment\", \"backend\": \"OpenGL\", \"language\": \"GLSL\", \"source\": \"lit.frag.glsl\" }\n";
        manifest << "      ]\n";
        manifest << "    }\n";
        manifest << "  ]\n";
        manifest << "}\n";
    }

    AssetDatabase database;
    database.Initialize(projectRoot.string().c_str());

    AssetDatabase::ResolvedAsset resolvedAsset;
    ASSERT_TRUE(database.EnsureArtifact("Assets/Shaders/lit.shader", ResourceType::Shader, resolvedAsset));
    ASSERT_TRUE(resolvedAsset.artifactReady);
    EXPECT_EQ(fs::path(resolvedAsset.artifactMainPath.CStr()).extension().string(), ".xcshader");
    EXPECT_TRUE(fs::exists(resolvedAsset.artifactMainPath.CStr()));

    ShaderLoader loader;
    LoadResult result = loader.Load(resolvedAsset.artifactMainPath.CStr());
    ASSERT_TRUE(result);
    ASSERT_NE(result.resource, nullptr);

    auto* shader = static_cast<Shader*>(result.resource);
    ASSERT_NE(shader, nullptr);
    EXPECT_TRUE(shader->IsValid());
    EXPECT_EQ(shader->GetName(), "ArtifactShader");
    EXPECT_EQ(
        fs::path(shader->GetPath().CStr()).lexically_normal().generic_string(),
        manifestPath.lexically_normal().generic_string());

    const ShaderPass* pass = shader->FindPass("ForwardLit");
    ASSERT_NE(pass, nullptr);
    ASSERT_EQ(pass->variants.Size(), 2u);
    ASSERT_EQ(pass->resources.Size(), 1u);

    const ShaderStageVariant* fragmentVariant =
        shader->FindVariant("ForwardLit", ShaderType::Fragment, ShaderBackend::OpenGL);
    ASSERT_NE(fragmentVariant, nullptr);
    EXPECT_NE(std::string(fragmentVariant->sourceCode.CStr()).find("ARTIFACT_GL_PS"), std::string::npos);

    delete shader;
    database.Shutdown();
    fs::remove_all(projectRoot);
}

TEST(ShaderLoader, AssetDatabaseCreatesShaderArtifactFromUnityLikeAuthoringAndTracksStageDependencies) {
    namespace fs = std::filesystem;
    using namespace std::chrono_literals;

    const fs::path projectRoot = fs::temp_directory_path() / "xc_shader_authoring_artifact_test";
    const fs::path shaderDir = projectRoot / "Assets" / "Shaders";
    const fs::path stageDir = shaderDir / "stages";
    const fs::path shaderPath = shaderDir / "lit.shader";
    const fs::path fragmentPath = stageDir / "lit.frag.glsl";

    fs::remove_all(projectRoot);
    fs::create_directories(stageDir);

    WriteTextFile(stageDir / "lit.vert.glsl", "#version 430\n// AUTHORING_ARTIFACT_GL_VS\nvoid main() {}\n");
    WriteTextFile(fragmentPath, "#version 430\n// AUTHORING_ARTIFACT_GL_PS\nvoid main() {}\n");
    WriteTextFile(
        shaderPath,
        R"(Shader "ArtifactAuthoringShader"
{
    Properties
    {
        _MainTex ("Main Tex", 2D) = "white" [Semantic(BaseColorTexture)]
    }
    SubShader
    {
        Pass
        {
            Name "ForwardLit"
            Tags { "LightMode" = "ForwardBase" }
            Resources
            {
                BaseColorTexture (Texture2D, 3, 0) [Semantic(BaseColorTexture)]
            }
            HLSLPROGRAM
            #pragma vertex main
            #pragma fragment main
            #pragma backend OpenGL GLSL "stages/lit.vert.glsl" "stages/lit.frag.glsl"
            ENDHLSL
        }
    }
}
)");

    AssetDatabase database;
    database.Initialize(projectRoot.string().c_str());

    AssetDatabase::ResolvedAsset firstResolve;
    ASSERT_TRUE(database.EnsureArtifact("Assets/Shaders/lit.shader", ResourceType::Shader, firstResolve));
    ASSERT_TRUE(firstResolve.artifactReady);
    EXPECT_EQ(fs::path(firstResolve.artifactMainPath.CStr()).extension().string(), ".xcshader");
    EXPECT_TRUE(fs::exists(firstResolve.artifactMainPath.CStr()));

    ShaderLoader loader;
    LoadResult firstLoad = loader.Load(firstResolve.artifactMainPath.CStr());
    ASSERT_TRUE(firstLoad);
    ASSERT_NE(firstLoad.resource, nullptr);
    auto* firstShader = static_cast<Shader*>(firstLoad.resource);
    ASSERT_NE(firstShader, nullptr);
    EXPECT_EQ(firstShader->GetName(), "ArtifactAuthoringShader");
    const ShaderStageVariant* firstFragment =
        firstShader->FindVariant("ForwardLit", ShaderType::Fragment, ShaderBackend::OpenGL);
    ASSERT_NE(firstFragment, nullptr);
    EXPECT_NE(std::string(firstFragment->sourceCode.CStr()).find("AUTHORING_ARTIFACT_GL_PS"), std::string::npos);
    delete firstShader;

    const String firstArtifactPath = firstResolve.artifactMainPath;
    database.Shutdown();

    std::this_thread::sleep_for(50ms);
    {
        std::ofstream fragmentFile(fragmentPath, std::ios::app);
        ASSERT_TRUE(fragmentFile.is_open());
        fragmentFile << "\n// force authoring dependency reimport\n";
        ASSERT_TRUE(static_cast<bool>(fragmentFile));
    }

    database.Initialize(projectRoot.string().c_str());
    AssetDatabase::ResolvedAsset secondResolve;
    ASSERT_TRUE(database.EnsureArtifact("Assets/Shaders/lit.shader", ResourceType::Shader, secondResolve));
    ASSERT_TRUE(secondResolve.artifactReady);
    EXPECT_NE(firstArtifactPath, secondResolve.artifactMainPath);
    EXPECT_TRUE(fs::exists(secondResolve.artifactMainPath.CStr()));
    database.Shutdown();

    fs::remove_all(projectRoot);
}

TEST(ShaderLoader, AssetDatabaseReimportsShaderWhenStageDependencyChanges) {
    namespace fs = std::filesystem;
    using namespace std::chrono_literals;

    const fs::path projectRoot = fs::temp_directory_path() / "xc_shader_dependency_reimport_test";
    const fs::path shaderDir = projectRoot / "Assets" / "Shaders";
    const fs::path manifestPath = shaderDir / "lit.shader";
    const fs::path fragmentPath = shaderDir / "lit.frag.glsl";

    fs::remove_all(projectRoot);
    fs::create_directories(shaderDir);

    WriteTextFile(shaderDir / "lit.vert.glsl", "#version 430\nvoid main() {}\n");
    WriteTextFile(fragmentPath, "#version 430\nvoid main() {}\n");

    {
        std::ofstream manifest(manifestPath);
        ASSERT_TRUE(manifest.is_open());
        manifest << "{\n";
        manifest << "  \"name\": \"DependencyShader\",\n";
        manifest << "  \"passes\": [\n";
        manifest << "    {\n";
        manifest << "      \"name\": \"ForwardLit\",\n";
        manifest << "      \"variants\": [\n";
        manifest << "        { \"stage\": \"Vertex\", \"backend\": \"OpenGL\", \"language\": \"GLSL\", \"source\": \"lit.vert.glsl\" },\n";
        manifest << "        { \"stage\": \"Fragment\", \"backend\": \"OpenGL\", \"language\": \"GLSL\", \"source\": \"lit.frag.glsl\" }\n";
        manifest << "      ]\n";
        manifest << "    }\n";
        manifest << "  ]\n";
        manifest << "}\n";
    }

    AssetDatabase database;
    database.Initialize(projectRoot.string().c_str());

    AssetDatabase::ResolvedAsset firstResolve;
    ASSERT_TRUE(database.EnsureArtifact("Assets/Shaders/lit.shader", ResourceType::Shader, firstResolve));
    ASSERT_TRUE(firstResolve.artifactReady);
    const String firstArtifactPath = firstResolve.artifactMainPath;
    database.Shutdown();

    std::this_thread::sleep_for(50ms);
    {
        std::ofstream fragmentFile(fragmentPath, std::ios::app);
        ASSERT_TRUE(fragmentFile.is_open());
        fragmentFile << "\n// force dependency reimport\n";
        ASSERT_TRUE(static_cast<bool>(fragmentFile));
    }

    database.Initialize(projectRoot.string().c_str());
    AssetDatabase::ResolvedAsset secondResolve;
    ASSERT_TRUE(database.EnsureArtifact("Assets/Shaders/lit.shader", ResourceType::Shader, secondResolve));
    ASSERT_TRUE(secondResolve.artifactReady);
    EXPECT_NE(firstArtifactPath, secondResolve.artifactMainPath);
    EXPECT_TRUE(fs::exists(secondResolve.artifactMainPath.CStr()));
    database.Shutdown();

    fs::remove_all(projectRoot);
}

TEST(ShaderLoader, LoadBuiltinForwardLitShaderBuildsBackendVariants) {
    ShaderLoader loader;
    LoadResult result = loader.Load(GetBuiltinForwardLitShaderPath());
    ASSERT_TRUE(result);
    ASSERT_NE(result.resource, nullptr);

    Shader* shader = static_cast<Shader*>(result.resource);
    ASSERT_NE(shader, nullptr);
    ASSERT_TRUE(shader->IsValid());

    const ShaderPass* pass = shader->FindPass("ForwardLit");
    ASSERT_NE(pass, nullptr);
    ASSERT_EQ(shader->GetProperties().Size(), 2u);
    ASSERT_EQ(pass->variants.Size(), 6u);
    ASSERT_EQ(pass->tags.Size(), 1u);
    ASSERT_EQ(pass->resources.Size(), 4u);
    EXPECT_EQ(pass->tags[0].name, "LightMode");
    EXPECT_EQ(pass->tags[0].value, "ForwardBase");

    const ShaderPropertyDesc* baseColorProperty = shader->FindProperty("_BaseColor");
    ASSERT_NE(baseColorProperty, nullptr);
    EXPECT_EQ(baseColorProperty->type, ShaderPropertyType::Color);
    EXPECT_EQ(baseColorProperty->semantic, "BaseColor");

    const ShaderPropertyDesc* baseMapProperty = shader->FindProperty("_MainTex");
    ASSERT_NE(baseMapProperty, nullptr);
    EXPECT_EQ(baseMapProperty->type, ShaderPropertyType::Texture2D);
    EXPECT_EQ(baseMapProperty->semantic, "BaseColorTexture");

    const ShaderResourceBindingDesc* perObjectBinding =
        shader->FindPassResourceBinding("ForwardLit", "PerObjectConstants");
    ASSERT_NE(perObjectBinding, nullptr);
    EXPECT_EQ(perObjectBinding->type, ShaderResourceType::ConstantBuffer);
    EXPECT_EQ(perObjectBinding->set, 1u);
    EXPECT_EQ(perObjectBinding->binding, 0u);
    EXPECT_EQ(perObjectBinding->semantic, "PerObject");

    EXPECT_NE(shader->FindVariant("ForwardLit", ShaderType::Vertex, ShaderBackend::D3D12), nullptr);
    EXPECT_NE(shader->FindVariant("ForwardLit", ShaderType::Fragment, ShaderBackend::D3D12), nullptr);
    EXPECT_NE(shader->FindVariant("ForwardLit", ShaderType::Vertex, ShaderBackend::OpenGL), nullptr);
    EXPECT_NE(shader->FindVariant("ForwardLit", ShaderType::Fragment, ShaderBackend::OpenGL), nullptr);
    EXPECT_NE(shader->FindVariant("ForwardLit", ShaderType::Vertex, ShaderBackend::Vulkan), nullptr);
    EXPECT_NE(shader->FindVariant("ForwardLit", ShaderType::Fragment, ShaderBackend::Vulkan), nullptr);

    const ShaderStageVariant* d3d12Vertex = shader->FindVariant(
        "ForwardLit",
        ShaderType::Vertex,
        ShaderBackend::D3D12);
    ASSERT_NE(d3d12Vertex, nullptr);
    EXPECT_NE(std::string(d3d12Vertex->sourceCode.CStr()).find("XC_BUILTIN_FORWARD_LIT_D3D12_VS"), std::string::npos);

    const ShaderStageVariant* openglFragment = shader->FindVariant(
        "ForwardLit",
        ShaderType::Fragment,
        ShaderBackend::OpenGL);
    ASSERT_NE(openglFragment, nullptr);
    EXPECT_NE(std::string(openglFragment->sourceCode.CStr()).find("XC_BUILTIN_FORWARD_LIT_OPENGL_PS"), std::string::npos);

    const ShaderStageVariant* vulkanFragment = shader->FindVariant(
        "ForwardLit",
        ShaderType::Fragment,
        ShaderBackend::Vulkan);
    ASSERT_NE(vulkanFragment, nullptr);
    EXPECT_NE(std::string(vulkanFragment->sourceCode.CStr()).find("XC_BUILTIN_FORWARD_LIT_VULKAN_PS"), std::string::npos);

    delete shader;
}

TEST(ShaderLoader, LoadBuiltinUnlitShaderBuildsBackendVariants) {
    ShaderLoader loader;
    LoadResult result = loader.Load(GetBuiltinUnlitShaderPath());
    ASSERT_TRUE(result);
    ASSERT_NE(result.resource, nullptr);

    Shader* shader = static_cast<Shader*>(result.resource);
    ASSERT_NE(shader, nullptr);
    ASSERT_TRUE(shader->IsValid());

    const ShaderPass* pass = shader->FindPass("Unlit");
    ASSERT_NE(pass, nullptr);
    ASSERT_EQ(shader->GetProperties().Size(), 2u);
    ASSERT_EQ(pass->variants.Size(), 6u);
    ASSERT_EQ(pass->tags.Size(), 1u);
    ASSERT_EQ(pass->resources.Size(), 4u);
    EXPECT_EQ(pass->tags[0].name, "LightMode");
    EXPECT_EQ(pass->tags[0].value, "Unlit");

    const ShaderPropertyDesc* baseColorProperty = shader->FindProperty("_BaseColor");
    ASSERT_NE(baseColorProperty, nullptr);
    EXPECT_EQ(baseColorProperty->type, ShaderPropertyType::Color);
    EXPECT_EQ(baseColorProperty->semantic, "BaseColor");

    const ShaderPropertyDesc* baseMapProperty = shader->FindProperty("_MainTex");
    ASSERT_NE(baseMapProperty, nullptr);
    EXPECT_EQ(baseMapProperty->type, ShaderPropertyType::Texture2D);
    EXPECT_EQ(baseMapProperty->semantic, "BaseColorTexture");

    const ShaderResourceBindingDesc* perObjectBinding =
        shader->FindPassResourceBinding("Unlit", "PerObjectConstants");
    ASSERT_NE(perObjectBinding, nullptr);
    EXPECT_EQ(perObjectBinding->type, ShaderResourceType::ConstantBuffer);
    EXPECT_EQ(perObjectBinding->set, 1u);
    EXPECT_EQ(perObjectBinding->binding, 0u);
    EXPECT_EQ(perObjectBinding->semantic, "PerObject");

    EXPECT_NE(shader->FindVariant("Unlit", ShaderType::Vertex, ShaderBackend::D3D12), nullptr);
    EXPECT_NE(shader->FindVariant("Unlit", ShaderType::Fragment, ShaderBackend::D3D12), nullptr);
    EXPECT_NE(shader->FindVariant("Unlit", ShaderType::Vertex, ShaderBackend::OpenGL), nullptr);
    EXPECT_NE(shader->FindVariant("Unlit", ShaderType::Fragment, ShaderBackend::OpenGL), nullptr);
    EXPECT_NE(shader->FindVariant("Unlit", ShaderType::Vertex, ShaderBackend::Vulkan), nullptr);
    EXPECT_NE(shader->FindVariant("Unlit", ShaderType::Fragment, ShaderBackend::Vulkan), nullptr);

    const ShaderStageVariant* d3d12Vertex = shader->FindVariant(
        "Unlit",
        ShaderType::Vertex,
        ShaderBackend::D3D12);
    ASSERT_NE(d3d12Vertex, nullptr);
    EXPECT_NE(std::string(d3d12Vertex->sourceCode.CStr()).find("XC_BUILTIN_UNLIT_D3D12_VS"), std::string::npos);

    const ShaderStageVariant* openglFragment = shader->FindVariant(
        "Unlit",
        ShaderType::Fragment,
        ShaderBackend::OpenGL);
    ASSERT_NE(openglFragment, nullptr);
    EXPECT_NE(std::string(openglFragment->sourceCode.CStr()).find("XC_BUILTIN_UNLIT_OPENGL_PS"), std::string::npos);

    const ShaderStageVariant* vulkanFragment = shader->FindVariant(
        "Unlit",
        ShaderType::Fragment,
        ShaderBackend::Vulkan);
    ASSERT_NE(vulkanFragment, nullptr);
    EXPECT_NE(std::string(vulkanFragment->sourceCode.CStr()).find("XC_BUILTIN_UNLIT_VULKAN_PS"), std::string::npos);

    delete shader;
}

TEST(ShaderLoader, LoadBuiltinObjectIdShaderBuildsBackendVariants) {
    ShaderLoader loader;
    LoadResult result = loader.Load(GetBuiltinObjectIdShaderPath());
    ASSERT_TRUE(result);
    ASSERT_NE(result.resource, nullptr);

    Shader* shader = static_cast<Shader*>(result.resource);
    ASSERT_NE(shader, nullptr);
    ASSERT_TRUE(shader->IsValid());

    const ShaderPass* pass = shader->FindPass("ObjectId");
    ASSERT_NE(pass, nullptr);
    ASSERT_EQ(pass->resources.Size(), 1u);
    EXPECT_EQ(pass->resources[0].semantic, "PerObject");
    EXPECT_EQ(pass->resources[0].type, ShaderResourceType::ConstantBuffer);
    EXPECT_EQ(pass->resources[0].set, 0u);
    EXPECT_EQ(pass->resources[0].binding, 0u);
    ASSERT_EQ(pass->variants.Size(), 6u);
    ASSERT_EQ(pass->tags.Size(), 1u);
    EXPECT_EQ(pass->tags[0].name, "LightMode");
    EXPECT_EQ(pass->tags[0].value, "ObjectId");

    EXPECT_NE(shader->FindVariant("ObjectId", ShaderType::Vertex, ShaderBackend::D3D12), nullptr);
    EXPECT_NE(shader->FindVariant("ObjectId", ShaderType::Fragment, ShaderBackend::D3D12), nullptr);
    EXPECT_NE(shader->FindVariant("ObjectId", ShaderType::Vertex, ShaderBackend::OpenGL), nullptr);
    EXPECT_NE(shader->FindVariant("ObjectId", ShaderType::Fragment, ShaderBackend::OpenGL), nullptr);
    EXPECT_NE(shader->FindVariant("ObjectId", ShaderType::Vertex, ShaderBackend::Vulkan), nullptr);
    EXPECT_NE(shader->FindVariant("ObjectId", ShaderType::Fragment, ShaderBackend::Vulkan), nullptr);

    const ShaderStageVariant* d3d12Vertex = shader->FindVariant(
        "ObjectId",
        ShaderType::Vertex,
        ShaderBackend::D3D12);
    ASSERT_NE(d3d12Vertex, nullptr);
    EXPECT_NE(std::string(d3d12Vertex->sourceCode.CStr()).find("XC_BUILTIN_OBJECT_ID_D3D12_VS"), std::string::npos);

    const ShaderStageVariant* openglFragment = shader->FindVariant(
        "ObjectId",
        ShaderType::Fragment,
        ShaderBackend::OpenGL);
    ASSERT_NE(openglFragment, nullptr);
    EXPECT_NE(std::string(openglFragment->sourceCode.CStr()).find("XC_BUILTIN_OBJECT_ID_OPENGL_PS"), std::string::npos);

    const ShaderStageVariant* vulkanFragment = shader->FindVariant(
        "ObjectId",
        ShaderType::Fragment,
        ShaderBackend::Vulkan);
    ASSERT_NE(vulkanFragment, nullptr);
    EXPECT_NE(std::string(vulkanFragment->sourceCode.CStr()).find("XC_BUILTIN_OBJECT_ID_VULKAN_PS"), std::string::npos);

    delete shader;
}

TEST(ShaderLoader, LoadBuiltinDepthOnlyShaderBuildsBackendVariants) {
    ShaderLoader loader;
    LoadResult result = loader.Load(GetBuiltinDepthOnlyShaderPath());
    ASSERT_TRUE(result);
    ASSERT_NE(result.resource, nullptr);

    Shader* shader = static_cast<Shader*>(result.resource);
    ASSERT_NE(shader, nullptr);
    ASSERT_TRUE(shader->IsValid());

    const ShaderPass* pass = shader->FindPass("DepthOnly");
    ASSERT_NE(pass, nullptr);
    ASSERT_EQ(pass->resources.Size(), 1u);
    EXPECT_EQ(pass->resources[0].semantic, "PerObject");
    EXPECT_EQ(pass->resources[0].type, ShaderResourceType::ConstantBuffer);
    EXPECT_EQ(pass->resources[0].set, 0u);
    EXPECT_EQ(pass->resources[0].binding, 0u);
    ASSERT_EQ(pass->variants.Size(), 6u);
    ASSERT_EQ(pass->tags.Size(), 1u);
    EXPECT_EQ(pass->tags[0].name, "LightMode");
    EXPECT_EQ(pass->tags[0].value, "DepthOnly");

    EXPECT_NE(shader->FindVariant("DepthOnly", ShaderType::Vertex, ShaderBackend::D3D12), nullptr);
    EXPECT_NE(shader->FindVariant("DepthOnly", ShaderType::Fragment, ShaderBackend::D3D12), nullptr);
    EXPECT_NE(shader->FindVariant("DepthOnly", ShaderType::Vertex, ShaderBackend::OpenGL), nullptr);
    EXPECT_NE(shader->FindVariant("DepthOnly", ShaderType::Fragment, ShaderBackend::OpenGL), nullptr);
    EXPECT_NE(shader->FindVariant("DepthOnly", ShaderType::Vertex, ShaderBackend::Vulkan), nullptr);
    EXPECT_NE(shader->FindVariant("DepthOnly", ShaderType::Fragment, ShaderBackend::Vulkan), nullptr);

    const ShaderStageVariant* d3d12Vertex = shader->FindVariant(
        "DepthOnly",
        ShaderType::Vertex,
        ShaderBackend::D3D12);
    ASSERT_NE(d3d12Vertex, nullptr);
    EXPECT_NE(std::string(d3d12Vertex->sourceCode.CStr()).find("XC_BUILTIN_DEPTH_ONLY_D3D12_VS"), std::string::npos);

    const ShaderStageVariant* openglFragment = shader->FindVariant(
        "DepthOnly",
        ShaderType::Fragment,
        ShaderBackend::OpenGL);
    ASSERT_NE(openglFragment, nullptr);
    EXPECT_NE(std::string(openglFragment->sourceCode.CStr()).find("XC_BUILTIN_DEPTH_ONLY_OPENGL_PS"), std::string::npos);

    const ShaderStageVariant* vulkanFragment = shader->FindVariant(
        "DepthOnly",
        ShaderType::Fragment,
        ShaderBackend::Vulkan);
    ASSERT_NE(vulkanFragment, nullptr);
    EXPECT_NE(std::string(vulkanFragment->sourceCode.CStr()).find("XC_BUILTIN_DEPTH_ONLY_VULKAN_PS"), std::string::npos);

    delete shader;
}

TEST(ShaderLoader, LoadBuiltinShadowCasterShaderBuildsBackendVariants) {
    ShaderLoader loader;
    LoadResult result = loader.Load(GetBuiltinShadowCasterShaderPath());
    ASSERT_TRUE(result);
    ASSERT_NE(result.resource, nullptr);

    Shader* shader = static_cast<Shader*>(result.resource);
    ASSERT_NE(shader, nullptr);
    ASSERT_TRUE(shader->IsValid());

    const ShaderPass* pass = shader->FindPass("ShadowCaster");
    ASSERT_NE(pass, nullptr);
    ASSERT_EQ(pass->resources.Size(), 1u);
    EXPECT_EQ(pass->resources[0].semantic, "PerObject");
    EXPECT_EQ(pass->resources[0].type, ShaderResourceType::ConstantBuffer);
    EXPECT_EQ(pass->resources[0].set, 0u);
    EXPECT_EQ(pass->resources[0].binding, 0u);
    ASSERT_EQ(pass->variants.Size(), 6u);
    ASSERT_EQ(pass->tags.Size(), 1u);
    EXPECT_EQ(pass->tags[0].name, "LightMode");
    EXPECT_EQ(pass->tags[0].value, "ShadowCaster");

    EXPECT_NE(shader->FindVariant("ShadowCaster", ShaderType::Vertex, ShaderBackend::D3D12), nullptr);
    EXPECT_NE(shader->FindVariant("ShadowCaster", ShaderType::Fragment, ShaderBackend::D3D12), nullptr);
    EXPECT_NE(shader->FindVariant("ShadowCaster", ShaderType::Vertex, ShaderBackend::OpenGL), nullptr);
    EXPECT_NE(shader->FindVariant("ShadowCaster", ShaderType::Fragment, ShaderBackend::OpenGL), nullptr);
    EXPECT_NE(shader->FindVariant("ShadowCaster", ShaderType::Vertex, ShaderBackend::Vulkan), nullptr);
    EXPECT_NE(shader->FindVariant("ShadowCaster", ShaderType::Fragment, ShaderBackend::Vulkan), nullptr);

    const ShaderStageVariant* d3d12Vertex = shader->FindVariant(
        "ShadowCaster",
        ShaderType::Vertex,
        ShaderBackend::D3D12);
    ASSERT_NE(d3d12Vertex, nullptr);
    EXPECT_NE(
        std::string(d3d12Vertex->sourceCode.CStr()).find("XC_BUILTIN_SHADOW_CASTER_D3D12_VS"),
        std::string::npos);

    const ShaderStageVariant* openglFragment = shader->FindVariant(
        "ShadowCaster",
        ShaderType::Fragment,
        ShaderBackend::OpenGL);
    ASSERT_NE(openglFragment, nullptr);
    EXPECT_NE(
        std::string(openglFragment->sourceCode.CStr()).find("XC_BUILTIN_SHADOW_CASTER_OPENGL_PS"),
        std::string::npos);

    const ShaderStageVariant* vulkanFragment = shader->FindVariant(
        "ShadowCaster",
        ShaderType::Fragment,
        ShaderBackend::Vulkan);
    ASSERT_NE(vulkanFragment, nullptr);
    EXPECT_NE(
        std::string(vulkanFragment->sourceCode.CStr()).find("XC_BUILTIN_SHADOW_CASTER_VULKAN_PS"),
        std::string::npos);

    delete shader;
}

TEST(ShaderLoader, ResourceManagerLazilyLoadsBuiltinForwardLitShader) {
    ResourceManager& manager = ResourceManager::Get();
    manager.Shutdown();
    manager.UnregisterLoader(ResourceType::Shader);

    ResourceHandle<Shader> shaderHandle = manager.Load<Shader>(GetBuiltinForwardLitShaderPath());
    ASSERT_TRUE(shaderHandle.IsValid());
    ASSERT_NE(shaderHandle->FindPass("ForwardLit"), nullptr);

    ResourceHandle<Shader> unlitShaderHandle = manager.Load<Shader>(GetBuiltinUnlitShaderPath());
    ASSERT_TRUE(unlitShaderHandle.IsValid());
    ASSERT_NE(unlitShaderHandle->FindPass("Unlit"), nullptr);

    ResourceHandle<Shader> objectIdShaderHandle = manager.Load<Shader>(GetBuiltinObjectIdShaderPath());
    ASSERT_TRUE(objectIdShaderHandle.IsValid());
    ASSERT_NE(objectIdShaderHandle->FindPass("ObjectId"), nullptr);

    manager.Shutdown();
}

TEST(ShaderLoader, ResourceManagerLoadsBuiltinShadersOutsideProjectWorkingDirectory) {
    namespace fs = std::filesystem;

    ResourceManager& manager = ResourceManager::Get();
    const fs::path previousPath = fs::current_path();
    const String previousResourceRoot = manager.GetResourceRoot();
    const fs::path isolatedWorkingDirectory = fs::temp_directory_path() / "xc_builtin_shader_out_of_tree";

    fs::remove_all(isolatedWorkingDirectory);
    fs::create_directories(isolatedWorkingDirectory);

    manager.Shutdown();
    manager.SetResourceRoot("");
    fs::current_path(isolatedWorkingDirectory);

    auto expectBuiltinShader = [&](const String& path,
                                   const char* passName,
                                   ShaderType stage,
                                   ShaderBackend backend,
                                   const char* marker) {
        const ResourceHandle<Shader> shaderHandle = manager.Load<Shader>(path);
        EXPECT_TRUE(shaderHandle.IsValid()) << path.CStr();
        if (!shaderHandle.IsValid()) {
            return;
        }

        EXPECT_NE(shaderHandle->FindPass(passName), nullptr) << path.CStr();
        const ShaderStageVariant* variant = shaderHandle->FindVariant(passName, stage, backend);
        EXPECT_NE(variant, nullptr) << path.CStr();
        if (variant != nullptr) {
            EXPECT_NE(std::string(variant->sourceCode.CStr()).find(marker), std::string::npos) << path.CStr();
        }
    };

    expectBuiltinShader(
        GetBuiltinForwardLitShaderPath(),
        "ForwardLit",
        ShaderType::Vertex,
        ShaderBackend::D3D12,
        "XC_BUILTIN_FORWARD_LIT_D3D12_VS");
    expectBuiltinShader(
        GetBuiltinUnlitShaderPath(),
        "Unlit",
        ShaderType::Fragment,
        ShaderBackend::OpenGL,
        "XC_BUILTIN_UNLIT_OPENGL_PS");
    expectBuiltinShader(
        GetBuiltinObjectIdShaderPath(),
        "ObjectId",
        ShaderType::Fragment,
        ShaderBackend::Vulkan,
        "XC_BUILTIN_OBJECT_ID_VULKAN_PS");

    fs::current_path(previousPath);
    manager.SetResourceRoot(previousResourceRoot);
    manager.Shutdown();
    fs::remove_all(isolatedWorkingDirectory);
}

} // namespace