// Copyright (c) 2020 by Chrono

#ifndef _CONFIG_HPP

#define _CONFIG_HPP

#include "cpplang.hpp"

extern "C" {

#include <luajit.h>

#include <lualib.h>

#include <lauxlib.h>

}

#include <LuaBridge/LuaBridge.h>

BEGIN_NAMESPACE(cpp_study)

class Config final

{

public:

using vm_type = std::shared_ptr<lua_State>;

using value_type = luabridge::LuaRef;

using string_type = std::string;

using string_view_type = const std::string&;

using regex_type = std::regex;

using match_type = std::smatch;

public:

Config() noexcept

{

assert(m_vm);

luaL_openlibs(m_vm.get());

}

~Config() = default;

public:

void load(string_view_type filename) const

{

auto status = luaL_dofile(m_vm.get(), filename.c_str());

if (status != 0) {

throw std::runtime_error("failed to parse config");

}

}

template<typename T>

T get(string_view_type key) const

{

if (!std::regex_match(key, m_what, m_reg)) {

throw std::runtime_error("config key error");

}

auto w1 = m_what[1].str();

auto w2 = m_what[2].str();

using namespace luabridge;

auto v = getGlobal(

m_vm.get(), w1.c_str());

return LuaRef_cast<T>(v[w2]);

}

private:

vm_type m_vm {luaL_newstate(), lua_close};

const regex_type m_reg {R"(^(\w+)\.(\w+)$)"};

mutable match_type m_what;

};

END_NAMESPACE(cpp_study)

#endif //_CONFIG_HPP