#include <gtest/gtest.h>
#include <XCEngine/Core/Asset/ArtifactContainer.h>
#include <XCEngine/Core/Asset/ArtifactFormats.h>
#include <XCEngine/Core/Asset/AssetDatabase.h>
#include <XCEngine/Core/Asset/AssetRef.h>
#include <XCEngine/Core/Asset/ResourceManager.h>
#include <XCEngine/Resources/Texture/TextureImportSettings.h>
#include <XCEngine/Resources/Texture/TextureLoader.h>
#include <XCEngine/Core/Asset/ResourceTypes.h>
#include <XCEngine/Core/Containers/Array.h>

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

using namespace XCEngine::Resources;
using namespace XCEngine::Containers;
namespace Core = XCEngine::Core;

namespace {

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

TEST(TextureLoader, GetResourceType) {
    TextureLoader loader;
    EXPECT_EQ(loader.GetResourceType(), ResourceType::Texture);
}

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

TEST(TextureLoader, CanLoad) {
    TextureLoader loader;
    EXPECT_TRUE(loader.CanLoad("test.png"));
    EXPECT_TRUE(loader.CanLoad("test.jpg"));
    EXPECT_TRUE(loader.CanLoad("test.tga"));
    EXPECT_FALSE(loader.CanLoad("test.txt"));
    EXPECT_FALSE(loader.CanLoad("test.obj"));
}

TEST(TextureLoader, LoadInvalidPath) {
    TextureLoader loader;
    LoadResult result = loader.Load("invalid/path/texture.png");
    EXPECT_FALSE(result);
}

TEST(TextureLoader, LoadValidBmpTexture) {
    TextureLoader loader;
    const std::string path = GetTextureFixturePath("checker.bmp");

    LoadResult result = loader.Load(path.c_str());
    ASSERT_TRUE(result);
    ASSERT_NE(result.resource, nullptr);

    auto* texture = static_cast<Texture*>(result.resource);
    EXPECT_EQ(texture->GetWidth(), 2u);
    EXPECT_EQ(texture->GetHeight(), 2u);
    EXPECT_EQ(texture->GetTextureType(), TextureType::Texture2D);
    EXPECT_EQ(texture->GetFormat(), TextureFormat::RGBA8_UNORM);
    EXPECT_EQ(texture->GetPixelDataSize(), 16u);

    delete texture;
}

TEST(TextureLoader, LoadValidBmpTextureAsSRGBWhenRequested) {
    TextureLoader loader;
    TextureImportSettings settings;
    settings.SetSRGB(true);

    const std::string path = GetTextureFixturePath("checker.bmp");
    LoadResult result = loader.Load(path.c_str(), &settings);
    ASSERT_TRUE(result);
    ASSERT_NE(result.resource, nullptr);

    auto* texture = static_cast<Texture*>(result.resource);
    EXPECT_EQ(texture->GetWidth(), 2u);
    EXPECT_EQ(texture->GetHeight(), 2u);
    EXPECT_EQ(texture->GetFormat(), TextureFormat::RGBA8_SRGB);

    delete texture;
}

TEST(TextureLoader, AssetDatabaseCreatesTextureArtifactAndReusesItWithoutReimport) {
    namespace fs = std::filesystem;
    using namespace std::chrono_literals;

    const fs::path projectRoot = fs::temp_directory_path() / "xc_texture_library_cache_test";
    const fs::path assetsDir = projectRoot / "Assets";
    const fs::path texturePath = assetsDir / "checker.bmp";

    fs::remove_all(projectRoot);
    fs::create_directories(assetsDir);
    fs::copy_file(GetTextureFixturePath("checker.bmp"), texturePath, fs::copy_options::overwrite_existing);

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

    AssetDatabase::ResolvedAsset firstResolve;
    ASSERT_TRUE(database.EnsureArtifact("Assets/checker.bmp", ResourceType::Texture, firstResolve));
    ASSERT_TRUE(firstResolve.exists);
    ASSERT_TRUE(firstResolve.artifactReady);
    EXPECT_TRUE(fs::exists(projectRoot / "Assets" / "checker.bmp.meta"));
    EXPECT_TRUE(fs::exists(projectRoot / "Library" / "assets.db"));
    EXPECT_TRUE(fs::exists(projectRoot / "Library" / "artifacts.db"));
    EXPECT_TRUE(fs::exists(firstResolve.artifactMainPath.CStr()));
    const fs::path firstArtifactPath(firstResolve.artifactMainPath.CStr());
    ASSERT_TRUE(firstArtifactPath.has_filename());
    ASSERT_TRUE(firstArtifactPath.has_parent_path());
    EXPECT_EQ(firstArtifactPath.parent_path().filename().string(),
              firstArtifactPath.stem().string().substr(0, 2));

    std::ifstream metaFile(projectRoot / "Assets" / "checker.bmp.meta");
    ASSERT_TRUE(metaFile.is_open());
    std::string metaText((std::istreambuf_iterator<char>(metaFile)), std::istreambuf_iterator<char>());
    EXPECT_NE(metaText.find("guid:"), std::string::npos);
    metaFile.close();

    AssetRef assetRef;
    ASSERT_TRUE(database.TryGetAssetRef("Assets/checker.bmp", ResourceType::Texture, assetRef));
    EXPECT_TRUE(assetRef.IsValid());

    const auto originalArtifactWriteTime = fs::last_write_time(firstResolve.artifactMainPath.CStr());
    std::this_thread::sleep_for(50ms);

    AssetDatabase::ResolvedAsset secondResolve;
    ASSERT_TRUE(database.EnsureArtifact("Assets/checker.bmp", ResourceType::Texture, secondResolve));
    EXPECT_EQ(firstResolve.artifactMainPath, secondResolve.artifactMainPath);
    EXPECT_EQ(originalArtifactWriteTime, fs::last_write_time(secondResolve.artifactMainPath.CStr()));

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

TEST(TextureLoader, ResourceManagerLoadsTextureByAssetRefFromProjectAssets) {
    namespace fs = std::filesystem;

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

    const fs::path projectRoot = fs::temp_directory_path() / "xc_texture_asset_ref_test";
    const fs::path assetsDir = projectRoot / "Assets";
    const fs::path texturePath = assetsDir / "checker.bmp";

    fs::remove_all(projectRoot);
    fs::create_directories(assetsDir);
    fs::copy_file(GetTextureFixturePath("checker.bmp"), texturePath, fs::copy_options::overwrite_existing);

    manager.SetResourceRoot(projectRoot.string().c_str());

    {
        const auto firstHandle = manager.Load<Texture>("Assets/checker.bmp");
        ASSERT_TRUE(firstHandle.IsValid());
        EXPECT_EQ(firstHandle->GetWidth(), 2u);
        EXPECT_EQ(firstHandle->GetHeight(), 2u);

        AssetRef assetRef;
        ASSERT_TRUE(manager.TryGetAssetRef("Assets/checker.bmp", ResourceType::Texture, assetRef));
        EXPECT_TRUE(assetRef.IsValid());

        manager.UnloadAll();

        const auto secondHandle = manager.Load<Texture>(assetRef);
        ASSERT_TRUE(secondHandle.IsValid());
        EXPECT_EQ(secondHandle->GetWidth(), 2u);
        EXPECT_EQ(secondHandle->GetHeight(), 2u);
        EXPECT_EQ(secondHandle->GetPath(), "Assets/checker.bmp");
    }

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

TEST(TextureLoader, ResourceManagerLoadsLibraryArtifactTextureWithoutReimportingIt) {
    namespace fs = std::filesystem;

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

    const fs::path projectRoot = fs::temp_directory_path() / "xc_texture_library_artifact_direct_load_test";
    const fs::path assetsDir = projectRoot / "Assets";
    const fs::path texturePath = assetsDir / "checker.bmp";

    fs::remove_all(projectRoot);
    fs::create_directories(assetsDir);
    fs::copy_file(GetTextureFixturePath("checker.bmp"), texturePath, fs::copy_options::overwrite_existing);

    manager.SetResourceRoot(projectRoot.string().c_str());
    const AssetImportService::ImportStatusSnapshot bootstrapStatus = manager.GetProjectAssetImportStatus();
    EXPECT_TRUE(bootstrapStatus.HasValue());
    EXPECT_TRUE(bootstrapStatus.success);
    EXPECT_EQ(std::string(bootstrapStatus.operation.CStr()), "Bootstrap Project");
    EXPECT_GT(bootstrapStatus.startedAtMs, 0u);
    EXPECT_GE(bootstrapStatus.completedAtMs, bootstrapStatus.startedAtMs);
    EXPECT_EQ(bootstrapStatus.durationMs, bootstrapStatus.completedAtMs - bootstrapStatus.startedAtMs);

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

    AssetDatabase::ResolvedAsset resolvedAsset;
    ASSERT_TRUE(database.EnsureArtifact("Assets/checker.bmp", ResourceType::Texture, resolvedAsset));
    ASSERT_TRUE(resolvedAsset.artifactReady);

    std::error_code ec;
    const fs::path relativeArtifactPath =
        fs::relative(fs::path(resolvedAsset.artifactMainPath.CStr()), projectRoot, ec);
    ASSERT_FALSE(ec);
    ASSERT_FALSE(relativeArtifactPath.empty());

    const auto textureHandle = manager.Load<Texture>(relativeArtifactPath.generic_string().c_str());
    ASSERT_TRUE(textureHandle.IsValid());
    EXPECT_EQ(textureHandle->GetWidth(), 2u);
    EXPECT_EQ(textureHandle->GetHeight(), 2u);
    EXPECT_EQ(textureHandle->GetPath(), relativeArtifactPath.generic_string().c_str());
    const AssetImportService::ImportStatusSnapshot postLoadStatus = manager.GetProjectAssetImportStatus();
    EXPECT_TRUE(postLoadStatus.HasValue());
    EXPECT_EQ(std::string(postLoadStatus.operation.CStr()), "Bootstrap Project");
    EXPECT_GT(postLoadStatus.startedAtMs, 0u);
    EXPECT_GE(postLoadStatus.completedAtMs, postLoadStatus.startedAtMs);
    EXPECT_EQ(postLoadStatus.durationMs, postLoadStatus.completedAtMs - postLoadStatus.startedAtMs);

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

TEST(TextureLoader, LoadTextureArtifactFromContainerEntryPath) {
    namespace fs = std::filesystem;

    const fs::path projectRoot = fs::temp_directory_path() / "xc_texture_container_entry_path_test";
    fs::remove_all(projectRoot);
    fs::create_directories(projectRoot);

    ArtifactContainerWriter writer;

    TextureArtifactHeader header;
    header.textureType = static_cast<Core::uint32>(TextureType::Texture2D);
    header.textureFormat = static_cast<Core::uint32>(TextureFormat::RGBA8_UNORM);
    header.width = 2;
    header.height = 2;
    header.depth = 1;
    header.mipLevels = 1;
    header.arraySize = 1;
    header.pixelDataSize = 16;

    ArtifactContainerEntry textureEntry;
    textureEntry.name = "texture_0.xctex";
    textureEntry.resourceType = ResourceType::Texture;
    textureEntry.payload.Resize(sizeof(TextureArtifactHeader) + static_cast<size_t>(header.pixelDataSize));
    std::memcpy(textureEntry.payload.Data(), &header, sizeof(TextureArtifactHeader));

    Core::uint8* pixelBytes = textureEntry.payload.Data() + sizeof(TextureArtifactHeader);
    const Core::uint8 pixelData[16] = {
        255, 0, 0, 255,
        0, 255, 0, 255,
        0, 0, 255, 255,
        255, 255, 255, 255
    };
    std::memcpy(pixelBytes, pixelData, sizeof(pixelData));
    writer.AddEntry(std::move(textureEntry));

    const String containerPath =
        (projectRoot / "Library" / "Artifacts" / "ab" / "artifact.xcmodel").string().c_str();
    String errorMessage;
    ASSERT_TRUE(writer.WriteToFile(containerPath, &errorMessage))
        << errorMessage.CStr();

    TextureLoader loader;
    const String virtualPath =
        BuildArtifactContainerEntryPath(containerPath, "texture_0.xctex");
    LoadResult result = loader.Load(virtualPath);
    ASSERT_TRUE(result) << result.errorMessage.CStr();
    ASSERT_NE(result.resource, nullptr);

    auto* texture = static_cast<Texture*>(result.resource);
    EXPECT_EQ(texture->GetWidth(), 2u);
    EXPECT_EQ(texture->GetHeight(), 2u);
    EXPECT_EQ(texture->GetTextureType(), TextureType::Texture2D);
    EXPECT_EQ(texture->GetFormat(), TextureFormat::RGBA8_UNORM);
    EXPECT_EQ(texture->GetPixelDataSize(), 16u);
    EXPECT_EQ(texture->GetPath(), virtualPath);

    delete texture;
    fs::remove_all(projectRoot);
}

} // namespace