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

#include <cstdio>
#include <filesystem>
#include <fstream>

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

namespace {

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_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());
}

} // namespace