lua_object.hpp

/*
   Copyright (C) 2011 - 2018 by Dmitry Kovalenko <nephro.wes@gmail.com>
   Part of the Battle for Wesnoth Project https://www.wesnoth.org/

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2 of the License, or
   (at your option) any later version.
   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY.

   See the COPYING file for more details.
*/

/**
 * @file
 * Lua object(value) wrapper implementation
 */


#ifndef LUA_OBJECT_HPP_INCLUDED
#define LUA_OBJECT_HPP_INCLUDED

#include "config.hpp"
#include "lua/lua.h"
#include "map/location.hpp"
#include "resources.hpp"
#include "scripting/lua_common.hpp"
#include "terrain/filter.hpp"
#include "variable.hpp"
#include "ai/default/contexts.hpp"
#include "ai/lua/aspect_advancements.hpp"

#include <iterator>
#include <string>
#include <vector>


namespace ai {


class lua_object_base {

public:
	lua_object_base();
	virtual ~lua_object_base() {}

	virtual void store(lua_State* L, int n) = 0;
};

template <typename T>
class lua_object : public lua_object_base
{

public:

	lua_object()
		: value_()
	{
		// empty
	}
	
	lua_object(const T& init)
		: value_(std::make_shared<T>(init))
	{
		// empty
	}

	std::shared_ptr<T> get()
	{
		return value_;
	}

	void store(lua_State* L, int n)
	{
		this->value_ = to_type(L, lua_absindex(L, n));
	}
	
	void push(lua_State* L)
	{
		from_type(L, this->value_);
	}

protected:

	// A group of functions that deal with the translation of the results to C++
	std::shared_ptr<T> to_type(lua_State *, int)
	{
		return std::shared_ptr<T>();
	}
	
	// A group of functions that deal with the translations of values back to Lua
	void from_type(lua_State* L, std::shared_ptr<T>)
	{
		lua_pushliteral(L, "Unsupported AI aspect type for Lua!");
		lua_error(L);
	}

	std::shared_ptr<T> value_;
};

template <>
inline std::shared_ptr<double> lua_object<double>::to_type(lua_State *L, int n)
{
	return std::make_shared<double>(lua_tonumber(L, n));
}

template <>
inline void lua_object<double>::from_type(lua_State *L, std::shared_ptr<double> value)
{
	if(value) lua_pushnumber(L, *value);
	else lua_pushnil(L);
}

template <>
inline std::shared_ptr<std::string> lua_object<std::string>::to_type(lua_State *L, int n)
{
	return std::make_shared<std::string>(lua_tostring(L, n));
}

template <>
inline void lua_object<std::string>::from_type(lua_State *L, std::shared_ptr<std::string> value)
{
	if(value) lua_pushlstring(L, value->c_str(), value->size());
	else lua_pushnil(L);
}

template <>
inline std::shared_ptr<bool> lua_object<bool>::to_type(lua_State *L, int n)
{
	return std::make_shared<bool>(luaW_toboolean(L, n));
}

template <>
inline void lua_object<bool>::from_type(lua_State *L, std::shared_ptr<bool> value)
{
	if(value) lua_pushboolean(L, *value);
	else lua_pushnil(L);
}

template <>
inline std::shared_ptr<int> lua_object<int>::to_type(lua_State *L, int n)
{
	return std::make_shared<int>(static_cast<int>(lua_tointeger(L, n)));
}

template <>
inline void lua_object<int>::from_type(lua_State *L, std::shared_ptr<int> value)
{
	if(value) lua_pushnumber(L, *value);
	else lua_pushnil(L);
}

template <>
inline std::shared_ptr< std::vector<std::string> > lua_object< std::vector<std::string> >::to_type(lua_State *L, int n)
{
	std::shared_ptr<std::vector<std::string>> v(new std::vector<std::string>());
	int l = lua_rawlen(L, n);
	for (int i = 1; i < l + 1; ++i)
	{
		lua_pushinteger(L, i);
		lua_gettable(L, n);
		std::string  s = lua_tostring(L, -1);
		lua_settop(L, n);
		v->push_back(s);
	}

	return v;
}

template <>
inline void lua_object< std::vector<std::string> >::from_type(lua_State *L, std::shared_ptr< std::vector<std::string> > value)
{
	if(value) {
		lua_createtable(L, value->size(), 0);
		for(const std::string& str : *value) {
			lua_pushlstring(L, str.c_str(), str.size());
			lua_rawseti(L, -1, lua_rawlen(L, -2) + 1);
		}
	} else lua_pushnil(L);
}

template <>
inline std::shared_ptr<config> lua_object<config>::to_type(lua_State *L, int n)
{
	std::shared_ptr<config> cfg(new config());
	luaW_toconfig(L, n, *cfg);
	return cfg;
}

template <>
inline void lua_object<config>::from_type(lua_State *L, std::shared_ptr<config> value)
{
	if(value) luaW_pushconfig(L, *value);
	else lua_pushnil(L);
}

template <>
inline std::shared_ptr<terrain_filter> lua_object<terrain_filter>::to_type(lua_State *L, int n)
{
	std::shared_ptr<config> cfg(new config());
	std::shared_ptr<vconfig> vcfg(new vconfig(*cfg));
	if (!luaW_tovconfig(L, n, *vcfg)) {
		cfg->add_child("not");
	}
	vcfg->make_safe();
	std::shared_ptr<terrain_filter> tf(new terrain_filter(*vcfg, resources::filter_con));
	return tf;
}

template <>
inline void lua_object<terrain_filter>::from_type(lua_State *L, std::shared_ptr<terrain_filter> value)
{
	if(value) {
		std::set<map_location> locs;
		value->get_locations(locs);
		lua_createtable(L, locs.size(), 0);
		for(const map_location& loc : locs) {
			luaW_pushlocation(L, loc);
			lua_rawseti(L, -2, lua_rawlen(L, -2) + 1);
		}
	} else lua_pushnil(L);
}

template <>
inline std::shared_ptr<std::vector<target> > lua_object< std::vector<target> >::to_type(lua_State *L, int n)
{
	std::shared_ptr<std::vector<target>> targets(new std::vector<target>());
	std::back_insert_iterator< std::vector<target> > tg(*targets);
	int l = lua_rawlen(L, n);

	for (int i = 1; i <= l; ++i)
	{
		lua_rawgeti(L, n, i); // st n + 1  TABLE @ N    table @ n + 1

		lua_pushstring(L, "loc"); // st n + 2
		lua_rawget(L, -2); // st n + 2

		lua_pushstring(L, "x"); // st n + 3
		lua_rawget(L, -2); // st n + 3
		int x = static_cast<int>(lua_tointeger(L, -1)); // st n + 3
		lua_pop(L, 1); // st n + 2

		lua_pushstring(L, "y"); // st n + 3
		lua_rawget(L, -2); // st n + 3
		int y = static_cast<int>(lua_tointeger(L, -1)); // st n + 3

		lua_pop(L, 2); // st n + 1

		lua_pushstring(L, "type"); // st n + 2
		lua_rawget(L, -2);  // st n + 2
		target::TYPE type = target::TYPE::EXPLICIT;
		if(lua_isnumber(L, -1)) {
			type = target::TYPE::from_int(static_cast<int>(lua_tointeger(L, -1)));  // st n + 2
		} else if(lua_isstring(L, -1)) {
			type = target::TYPE::string_to_enum(lua_tostring(L, -1));  // st n + 2
		}
		lua_pop(L, 1); // st n + 1


		lua_pushstring(L, "value");
		lua_rawget(L, -2);
		int value = static_cast<int>(lua_tointeger(L, -1));

		map_location ml(x, y, wml_loc());

		*tg = target(ml, value, type);
	}

	lua_settop(L, n);
	return targets;
}

template <>
inline std::shared_ptr<unit_advancements_aspect> lua_object<unit_advancements_aspect>::to_type(lua_State *L, int n)
{
	return std::make_shared<unit_advancements_aspect>(L, n);
}

// This one is too complex to define in the header.
struct aspect_attacks_lua_filter;
template <>
std::shared_ptr<aspect_attacks_lua_filter> lua_object<aspect_attacks_lua_filter>::to_type(lua_State *L, int n);
} // end of namespace ai


#endif