#if !defined(LUA_ENGINE_H)
#define LUA_ENGINE_H
#include "Service.h"
#include "Cache.h"
#include <vector>
#include <functional>
#include <string>
#include "DBLogger.h"
#include "croncpp/croncpp.h"
#include <ctime>
#include <queue>
#include "spdlog/spdlog.h"

struct ScheduledService {
	cron::cronexpr cron;
	std::time_t next_run;
	LuaService* service;
	std::string callback;

	void next();
	bool operator<(const ScheduledService& rhs) const;
};


class LuaEngine {
	private:
		LuaEngine();
	public:
		std::function<void(const TopicState& state)> publish;
		DBLogger db_logger;
		std::priority_queue<ScheduledService> time_schedule;

	static LuaEngine& get_instance() {
		static LuaEngine instance;

		return instance;
	}
	std::vector<LuaService> services;
	
	Cache cache;


	void load_services();
	void start_services();
	LuaService* create_service(std::string filename);
	LuaService* service_by_lua_state(lua_State* lua);
	LuaEngine(LuaEngine const&) = delete;
	void operator=(LuaEngine const&)  = delete;
};

template<typename Arg, typename... Args>
inline bool check_arguments(lua_State* lua, int stack_pos) {
    return check_arguments<Args...>(lua, stack_pos+1) && check_arguments<Arg>(lua, stack_pos);
}
 
template<typename Arg, typename... Args>
inline bool check_arguments(lua_State* lua) {
    int num_arg = sizeof...(Args) + 1;
    return check_arguments<Arg, Args...>(lua, num_arg * -1);
}
 
template <>
inline bool check_arguments<std::string>(lua_State* lua, int stack_pos) {
    return lua_isstring(lua, stack_pos);
}
 
template <>
inline bool check_arguments<int>(lua_State* lua, int stack_pos) {
    return lua_isnumber(lua, stack_pos);
}
 
template <>
inline bool check_arguments<bool>(lua_State* lua, int stack_pos) {
    return lua_isnumber(lua, stack_pos);
}

template<typename F>
void lua_func_call(LuaService& service, const std::string& lua_func, F push_params) {
	lua_getglobal(service.lua, lua_func.c_str());

	int num_arguments = push_params();

	if (lua_pcall(service.lua, num_arguments, 0, 0) != 0) {
		spdlog::error("[{}] Unable to call '{}'. [Lua: '{}']", lua_func, service.name);

		return;
	}
}
#endif // LUA_ENGINE_H