#include <gtest/gtest.h>

#include <XCEngine/Components/MeshFilterComponent.h>
#include <XCEngine/Components/MeshRendererComponent.h>
#include <XCEngine/Core/Asset/AssetRef.h>
#include <XCEngine/Core/Asset/ResourceManager.h>
#include <XCEngine/Resources/Model/Model.h>
#include <XCEngine/Scene/ModelSceneInstantiation.h>
#include <XCEngine/Scene/Scene.h>

#include <filesystem>
#include <fstream>

#ifdef _WIN32
#ifndef NOMINMAX
#define NOMINMAX
#endif
#include <windows.h>
#endif

using namespace XCEngine;
using namespace XCEngine::Components;
using namespace XCEngine::Resources;

namespace {

std::filesystem::path GetRepositoryRoot() {
    return std::filesystem::path(__FILE__).parent_path().parent_path().parent_path().parent_path();
}

std::string GetMeshFixturePath(const char* fileName) {
    return (std::filesystem::path(XCENGINE_TEST_FIXTURES_DIR) / "Resources" / "Mesh" / fileName).string();
}

void CopyTexturedTriangleFixture(const std::filesystem::path& assetsDir) {
    namespace fs = std::filesystem;

    fs::copy_file(
        GetMeshFixturePath("textured_triangle.obj"),
        assetsDir / "textured_triangle.obj",
        fs::copy_options::overwrite_existing);
    fs::copy_file(
        GetMeshFixturePath("textured_triangle.mtl"),
        assetsDir / "textured_triangle.mtl",
        fs::copy_options::overwrite_existing);
    fs::copy_file(
        GetMeshFixturePath("checker.bmp"),
        assetsDir / "checker.bmp",
        fs::copy_options::overwrite_existing);
}

#ifdef _WIN32
struct AssimpDllGuard {
    HMODULE module = nullptr;

    ~AssimpDllGuard() {
        if (module != nullptr) {
            FreeLibrary(module);
        }
    }
};
#endif

TEST(ModelSceneInstantiation, BuildsHierarchyFromManualModelGraph) {
    Scene scene("Instantiation Scene");
    Model model;
    IResource::ConstructParams params = {};
    params.name = "ManualModel";
    params.path = "Assets/manual_model.fbx";
    params.guid = ResourceGUID::Generate(params.path);
    model.Initialize(params);

    ModelNode rootNode;
    rootNode.name = "Root";
    rootNode.parentIndex = -1;
    rootNode.localPosition = Math::Vector3(1.0f, 2.0f, 3.0f);

    ModelNode childNode;
    childNode.name = "Child";
    childNode.parentIndex = 0;
    childNode.localPosition = Math::Vector3(4.0f, 5.0f, 6.0f);
    childNode.localScale = Math::Vector3(2.0f, 2.0f, 2.0f);

    model.AddNode(rootNode);
    model.AddNode(childNode);
    model.SetRootNodeIndex(0u);

    ModelSceneInstantiationResult result;
    Containers::String errorMessage;
    ASSERT_TRUE(InstantiateModelHierarchy(scene, model, AssetRef(), nullptr, &result, &errorMessage))
        << errorMessage.CStr();

    ASSERT_NE(result.rootObject, nullptr);
    EXPECT_EQ(result.rootObject->GetName(), "Root");
    ASSERT_EQ(result.nodeObjects.size(), 2u);
    ASSERT_NE(result.nodeObjects[1], nullptr);
    EXPECT_EQ(result.nodeObjects[1]->GetParent(), result.rootObject);
    EXPECT_EQ(result.rootObject->GetTransform()->GetLocalPosition(), Math::Vector3(1.0f, 2.0f, 3.0f));
    EXPECT_EQ(result.nodeObjects[1]->GetTransform()->GetLocalPosition(), Math::Vector3(4.0f, 5.0f, 6.0f));
    EXPECT_EQ(result.nodeObjects[1]->GetTransform()->GetLocalScale(), Math::Vector3(2.0f, 2.0f, 2.0f));
}

TEST(ModelSceneInstantiation, RestoresMeshAndMaterialSubAssetRefsFromImportedModel) {
    namespace fs = std::filesystem;

    const fs::path projectRoot = fs::temp_directory_path() / "xc_model_scene_instantiation";
    const fs::path assetsDir = projectRoot / "Assets";
    fs::remove_all(projectRoot);
    fs::create_directories(assetsDir);
    CopyTexturedTriangleFixture(assetsDir);

#ifdef _WIN32
    AssimpDllGuard dllGuard;
    const fs::path assimpDllPath = GetRepositoryRoot() / "engine" / "third_party" / "assimp" / "bin" / "assimp-vc143-mt.dll";
    ASSERT_TRUE(fs::exists(assimpDllPath));
    dllGuard.module = LoadLibraryW(assimpDllPath.wstring().c_str());
    ASSERT_NE(dllGuard.module, nullptr);
#endif

    ResourceManager& manager = ResourceManager::Get();
    manager.Initialize();
    manager.SetResourceRoot(projectRoot.string().c_str());

    const auto modelHandle = manager.Load<Model>("Assets/textured_triangle.obj");
    ASSERT_TRUE(modelHandle.IsValid());

    AssetRef modelAssetRef;
    ASSERT_TRUE(manager.TryGetAssetRef("Assets/textured_triangle.obj", ResourceType::Model, modelAssetRef));

    Scene scene("Instantiation Scene");
    ModelSceneInstantiationResult result;
    Containers::String errorMessage;
    ASSERT_TRUE(InstantiateModelHierarchy(scene, *modelHandle, modelAssetRef, nullptr, &result, &errorMessage))
        << errorMessage.CStr();

    ASSERT_NE(result.rootObject, nullptr);
    ASSERT_FALSE(result.meshObjects.empty());
    auto* meshObject = result.meshObjects.front();
    ASSERT_NE(meshObject, nullptr);

    auto* meshFilter = meshObject->GetComponent<MeshFilterComponent>();
    auto* meshRenderer = meshObject->GetComponent<MeshRendererComponent>();
    ASSERT_NE(meshFilter, nullptr);
    ASSERT_NE(meshRenderer, nullptr);
    ASSERT_NE(meshFilter->GetMesh(), nullptr);
    ASSERT_EQ(meshRenderer->GetMaterialCount(), 1u);
    ASSERT_NE(meshRenderer->GetMaterial(0), nullptr);

    const AssetRef& meshRef = meshFilter->GetMeshAssetRef();
    EXPECT_TRUE(meshRef.IsValid());
    EXPECT_EQ(meshRef.assetGuid, modelAssetRef.assetGuid);
    EXPECT_EQ(meshRef.localID, modelHandle->GetMeshBindings()[0].meshLocalID);
    EXPECT_EQ(meshRef.resourceType, ResourceType::Mesh);

    ASSERT_EQ(meshRenderer->GetMaterialAssetRefs().size(), 1u);
    const AssetRef& materialRef = meshRenderer->GetMaterialAssetRefs()[0];
    EXPECT_TRUE(materialRef.IsValid());
    EXPECT_EQ(materialRef.assetGuid, modelAssetRef.assetGuid);
    EXPECT_EQ(materialRef.localID, modelHandle->GetMaterialBindings()[0].materialLocalID);
    EXPECT_EQ(materialRef.resourceType, ResourceType::Material);

    const std::string serializedScene = scene.SerializeToString();
    EXPECT_NE(serializedScene.find("meshRef="), std::string::npos);
    EXPECT_EQ(serializedScene.find("meshRef=;"), std::string::npos);
    EXPECT_NE(serializedScene.find("materialRefs="), std::string::npos);
    EXPECT_EQ(serializedScene.find("materialRefs=;"), std::string::npos);

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

} // namespace