#include "services/impl/logger_service.hpp"
#include "services/impl/script_engine_service.hpp"
#include "services/impl/scene_script_service.hpp"
#include "services/impl/shader_script_service.hpp"
#include "services/interfaces/i_config_service.hpp"

#include <array>
#include <cmath>
#include <filesystem>
#include <iostream>
#include <memory>
#include <string>
#include <vector>

namespace {
constexpr std::array<float, 16> kIdentityMatrix = {
    1.0f, 0.0f, 0.0f, 0.0f,
    0.0f, 1.0f, 0.0f, 0.0f,
    0.0f, 0.0f, 1.0f, 0.0f,
    0.0f, 0.0f, 0.0f, 1.0f,
};

bool ApproximatelyEqual(float a, float b, float eps = 1e-5f) {
    return std::fabs(a - b) <= eps;
}

bool ExpectIdentity(const std::array<float, 16>& actual, const std::string& label, int& failures) {
    for (size_t i = 0; i < actual.size(); ++i) {
        if (!ApproximatelyEqual(actual[i], kIdentityMatrix[i])) {
            std::cerr << label << " differs at index " << i << " (" << actual[i] << " vs "
                      << kIdentityMatrix[i] << ")\n";
            ++failures;
            return false;
        }
    }
    return true;
}

std::filesystem::path GetTestScriptPath() {
    auto testDir = std::filesystem::path(__FILE__).parent_path();
    return testDir / "scripts" / "unit_cube_logic.lua";
}

class StubConfigService final : public sdl3cpp::services::IConfigService {
public:
    StubConfigService() {
        materialXConfig_.enabled = true;
        materialXConfig_.useConstantColor = true;
        materialXConfig_.shaderKey = "test";
        materialXConfig_.libraryPath = ResolveMaterialXLibraryPath();
    }

    uint32_t GetWindowWidth() const override { return 1; }
    uint32_t GetWindowHeight() const override { return 1; }
    std::filesystem::path GetScriptPath() const override { return {}; }
    bool IsLuaDebugEnabled() const override { return false; }
    std::string GetWindowTitle() const override { return ""; }
    const sdl3cpp::services::InputBindings& GetInputBindings() const override { return inputBindings_; }
    const sdl3cpp::services::MouseGrabConfig& GetMouseGrabConfig() const override { return mouseGrabConfig_; }
    const sdl3cpp::services::BgfxConfig& GetBgfxConfig() const override { return bgfxConfig_; }
    const sdl3cpp::services::MaterialXConfig& GetMaterialXConfig() const override { return materialXConfig_; }
    const std::vector<sdl3cpp::services::MaterialXMaterialConfig>& GetMaterialXMaterialConfigs() const override {
        return materialXMaterials_;
    }
    const sdl3cpp::services::GuiFontConfig& GetGuiFontConfig() const override { return guiFontConfig_; }
    const std::string& GetConfigJson() const override { return configJson_; }

private:
    static std::filesystem::path ResolveMaterialXLibraryPath() {
        auto repoRoot = std::filesystem::path(__FILE__).parent_path().parent_path();
        return repoRoot / "MaterialX" / "libraries";
    }

    sdl3cpp::services::InputBindings inputBindings_{};
    sdl3cpp::services::MouseGrabConfig mouseGrabConfig_{};
    sdl3cpp::services::BgfxConfig bgfxConfig_{};
    sdl3cpp::services::MaterialXConfig materialXConfig_{};
    std::vector<sdl3cpp::services::MaterialXMaterialConfig> materialXMaterials_{};
    sdl3cpp::services::GuiFontConfig guiFontConfig_{};
    std::string configJson_{};
};

void Assert(bool condition, const std::string& message, int& failures) {
    if (!condition) {
        std::cerr << "test failure: " << message << '\n';
        ++failures;
    }
}
} // namespace

int main() {
    int failures = 0;
    auto scriptPath = GetTestScriptPath();
    std::cout << "Loading Lua fixture: " << scriptPath << '\n';

    try {
        auto logger = std::make_shared<sdl3cpp::services::impl::LoggerService>();
        auto configService = std::make_shared<StubConfigService>();
        auto engineService = std::make_shared<sdl3cpp::services::impl::ScriptEngineService>(
            scriptPath,
            logger,
            nullptr,
            nullptr,
            nullptr,
            nullptr,
            nullptr,
            configService,
            false);
        engineService->Initialize();

        sdl3cpp::services::impl::SceneScriptService sceneService(engineService, logger);
        sdl3cpp::services::impl::ShaderScriptService shaderService(engineService, configService, logger);

        auto objects = sceneService.LoadSceneObjects();
        Assert(objects.size() == 1, "expected exactly one scene object", failures);
        if (!objects.empty()) {
            const auto& object = objects.front();
            Assert(object.vertices.size() == 3, "scene object should yield three vertices", failures);
            Assert(object.indices.size() == 3, "scene object should yield three indices", failures);
            Assert(object.shaderKeys.size() == 1, "shader keys should contain one entry", failures);
            if (!object.shaderKeys.empty()) {
                Assert(object.shaderKeys.front() == "test", "shader key should match fixture", failures);
            }
            const std::vector<uint16_t> expectedIndices{0, 1, 2};
            Assert(object.indices == expectedIndices, "indices should be zero-based", failures);
            Assert(object.computeModelMatrixRef >= 0,
                   "vertex object must keep a Lua reference", failures);

            auto objectMatrix = sceneService.ComputeModelMatrix(object.computeModelMatrixRef, 0.5f);
            ExpectIdentity(objectMatrix, "object compute_model_matrix", failures);
        }

        auto fallbackMatrix = sceneService.ComputeModelMatrix(-1, 1.0f);
        ExpectIdentity(fallbackMatrix, "global compute_model_matrix", failures);

        auto viewState = sceneService.GetViewState(1.33f);
        ExpectIdentity(viewState.viewProj, "view_projection matrix", failures);

        auto shaderMap = shaderService.LoadShaderPathsMap();
        Assert(shaderMap.size() == 1, "expected a single shader variant", failures);
        auto testEntry = shaderMap.find("test");
        Assert(testEntry != shaderMap.end(), "shader map missing test entry", failures);
        if (testEntry != shaderMap.end()) {
            Assert(!testEntry->second.vertexSource.empty(), "vertex shader source missing", failures);
            Assert(!testEntry->second.fragmentSource.empty(), "fragment shader source missing", failures);
        }
    } catch (const std::exception& ex) {
        std::cerr << "exception during tests: " << ex.what() << '\n';
        return 1;
    }

    if (failures == 0) {
        std::cout << "script_engine_tests: PASSED\n";
    } else {
        std::cerr << "script_engine_tests: FAILED (" << failures << " errors)\n";
    }

    return failures;
}