#include "vk_layer_setup.hpp"

#include <windows.h>

#include "coop/tool_paths.hpp"

namespace coop
{
namespace
{
// The Vulkan loader's per-user implicit-layer registry list. Each value is a manifest path; its
// DWORD data 0 = enabled.
constexpr const wchar_t* kImplicitLayersKey = L"SOFTWARE\\Khronos\\Vulkan\\ImplicitLayers";

std::wstring manifest_path()
{
	return exe_directory() + L"coop_vk_layer.json"; // staged next to coop_host.exe
}

std::wstring scoping_file()
{
	wchar_t dir[MAX_PATH] = {};
	const DWORD n = GetTempPathW(MAX_PATH, dir);
	return (n != 0 && n < MAX_PATH) ? std::wstring(dir) + L"coop_vk_target.txt" : std::wstring();
}
} // namespace

bool register_vk_layer(const std::wstring& target_image)
{
	// Write the scoping file (target image basename, UTF-8) the layer checks against its own image.
	const std::wstring sf = scoping_file();
	if (!sf.empty())
	{
		const std::size_t slash = target_image.find_last_of(L"\\/");
		const std::wstring base = slash == std::wstring::npos ? target_image : target_image.substr(slash + 1);
		const int n = WideCharToMultiByte(CP_UTF8, 0, base.c_str(), static_cast<int>(base.size()), nullptr, 0,
		                                  nullptr, nullptr);
		std::string utf8(static_cast<std::size_t>(n), '\0');
		WideCharToMultiByte(CP_UTF8, 0, base.c_str(), static_cast<int>(base.size()), utf8.data(), n, nullptr,
		                    nullptr);
		HANDLE f = CreateFileW(sf.c_str(), GENERIC_WRITE, 0, nullptr, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, nullptr);
		if (f != INVALID_HANDLE_VALUE)
		{
			DWORD written = 0;
			WriteFile(f, utf8.data(), static_cast<DWORD>(utf8.size()), &written, nullptr);
			CloseHandle(f);
		}
	}

	HKEY key = nullptr;
	if (RegCreateKeyExW(HKEY_CURRENT_USER, kImplicitLayersKey, 0, nullptr, 0, KEY_SET_VALUE, nullptr, &key,
	                    nullptr) != ERROR_SUCCESS)
	{
		return false;
	}
	const std::wstring mp = manifest_path();
	DWORD enabled = 0; // 0 = enabled, per the loader's convention
	const LONG r = RegSetValueExW(key, mp.c_str(), 0, REG_DWORD, reinterpret_cast<const BYTE*>(&enabled),
	                              sizeof(enabled));
	RegCloseKey(key);
	return r == ERROR_SUCCESS;
}

void unregister_vk_layer()
{
	HKEY key = nullptr;
	if (RegOpenKeyExW(HKEY_CURRENT_USER, kImplicitLayersKey, 0, KEY_SET_VALUE, &key) == ERROR_SUCCESS)
	{
		RegDeleteValueW(key, manifest_path().c_str());
		RegCloseKey(key);
	}
	const std::wstring sf = scoping_file();
	if (!sf.empty())
	{
		DeleteFileW(sf.c_str());
	}
}

} // namespace coop