/*
 *  The Mana Server
 *  Copyright (C) 2007-2010  The Mana World Development Team
 *  Copyright (C) 2010-2013  The Mana Developers
 *
 *  This file is part of The Mana Server.
 *
 *  The Mana Server 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
 *  any later version.
 *
 *  The Mana Server is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with The Mana Server.  If not, see <http://www.gnu.org/licenses/>.
 */


#include <cassert>

extern "C" {
#include <lualib.h>
#include <lauxlib.h>
}

#include "common/defines.h"
#include "common/resourcemanager.h"
#include "game-server/accountconnection.h"
#include "game-server/buysell.h"
#include "game-server/character.h"
#include "game-server/collisiondetection.h"
#include "game-server/combatcomponent.h"
#include "game-server/effect.h"
#include "game-server/gamehandler.h"
#include "game-server/inventory.h"
#include "game-server/item.h"
#include "game-server/itemmanager.h"
#include "game-server/map.h"
#include "game-server/mapcomposite.h"
#include "game-server/mapmanager.h"
#include "game-server/monster.h"
#include "game-server/monstermanager.h"
#include "game-server/npc.h"
#include "game-server/postman.h"
#include "game-server/quest.h"
#include "game-server/state.h"
#include "game-server/statuseffect.h"
#include "game-server/statusmanager.h"
#include "game-server/triggerareacomponent.h"
#include "net/messageout.h"
#include "scripting/luautil.h"
#include "scripting/luascript.h"
#include "scripting/scriptmanager.h"
#include "utils/logger.h"
#include "utils/speedconv.h"

#include <string.h>
#include <math.h>

/*
 * This file includes all script bindings available to LUA scripts.
 * When you add or change a script binding please run the update script in the
 * docs repository!
 *
 * http://doc.manasource.org/scripting
 */

/** LUA_CATEGORY Callbacks (callbacks)
 * **Note:** You can only assign a **single** function as callback.
 * When setting a new function the old one will not be called anymore.
 * Some of this callbacks are already used for the libmana.lua. Be careful when
 * using those since they will most likely break your code in other places.
 */

/** LUA on_update_derived_attribute (callbacks)
 * on_update_derived_attribute(function ref)
 **
 * Will call the function ''ref'' when an attribute changed and other attributes
 * need recalculation. The function is expected to recalculate those then.
 *
 * **See:** [[attributes.xml]] for more info.
 *
 */
static int on_update_derived_attribute(lua_State *s)
{
    luaL_checktype(s, 1, LUA_TFUNCTION);
    BeingComponent::setUpdateDerivedAttributesCallback(getScript(s));
    return 0;
}


/** LUA on_recalculate_base_attribute (callbacks)
 * on_recalculate_base_attribute(function ref)
 **
 * Will call the function ''ref'' when an attribute base needs to be recalculated.
 * The function is expected to do this recalculation then. The engine only
 * triggers this for characters. However you can use the same function for
 * recalculating derived attributes in the
 * [[scripting#on_update_derived_attribute|on_update_derived_attribute]] callback.
 *
 * **See:** [[attributes.xml]] for more info.
 */
static int on_recalculate_base_attribute(lua_State *s)
{
    luaL_checktype(s, 1, LUA_TFUNCTION);
    BeingComponent::setRecalculateBaseAttributeCallback(getScript(s));
    return 0;
}

/** LUA on_character_death (callbacks)
 * on_character_death(function ref)
 **
 * on_character_death( function(Character*) ): void
 * Sets a listener function to the character death event.
 */
static int on_character_death(lua_State *s)
{
    luaL_checktype(s, 1, LUA_TFUNCTION);
    CharacterComponent::setDeathCallback(getScript(s));
    return 0;
}

/** LUA on_character_death_accept (callbacks)
 * on_character_death_accept(function ref)
 **
 * Will make sure that the function ''ref'' gets called with the character
 * as argument as soon a character either pressed the ok dialouge in the death
 * message or left the game while being dead.
 */
static int on_character_death_accept(lua_State *s)
{
    luaL_checktype(s, 1, LUA_TFUNCTION);
    CharacterComponent::setDeathAcceptedCallback(getScript(s));
    return 0;
}

/** LUA on_character_login (callbacks)
 * on_character_login(function ref)
 **
 * Will make sure that function ''ref'' gets called with the character
 * as argument as soon a character logged in.
 */
static int on_character_login(lua_State *s)
{
    luaL_checktype(s, 1, LUA_TFUNCTION);
    CharacterComponent::setLoginCallback(getScript(s));
    return 0;
}

/** LUA on_being_death (callbacks)
 * on_being_death(function ref)
 **
 * Will make sure that the function ''ref'' gets called with the being
 * as argument as soon a being dies.
 */
static int on_being_death(lua_State *s)
{
    luaL_checktype(s, 1, LUA_TFUNCTION);
    LuaScript::setDeathNotificationCallback(getScript(s));
    return 0;
}

/** LUA on_being_remove (callbacks)
 * on_being_remove(function ref)
 **
 * Will make sure that the function ''ref'' gets called with the being
 * as argument as soon a being gets removed from a map.
 */
static int on_being_remove(lua_State *s)
{
    luaL_checktype(s, 1, LUA_TFUNCTION);
    LuaScript::setRemoveNotificationCallback(getScript(s));
    return 0;
}

/** LUA on_update (callbacks)
 * on_update(function ref)
 **
 * Will make sure that the function ''ref'' gets called every game tick.
 */
static int on_update(lua_State *s)
{
    luaL_checktype(s, 1, LUA_TFUNCTION);
    Script::setUpdateCallback(getScript(s));
    return 0;
}

/** LUA on_create_npc_delayed (callbacks)
 * on_create_npc_delayed(function ref)
 **
 * Will make sure that the function ''ref'' gets called with the
 * name, id, gender, x and y values as arguments of the npc when a npc should
 * be created at map init (Npcs defined directly in the map files use this).
 */
static int on_create_npc_delayed(lua_State *s)
{
    luaL_checktype(s, 1, LUA_TFUNCTION);
    Script::setCreateNpcDelayedCallback(getScript(s));
    return 0;
}

/** LUA on_map_initialize (callbacks)
 * on_map_initialize(function ref)
 **
 * Will make sure that the function ''ref'' gets called with the initialized
 * map as current map when the map is initialized.
 */
static int on_map_initialize(lua_State *s)
{
    luaL_checktype(s, 1, LUA_TFUNCTION);
    MapComposite::setInitializeCallback(getScript(s));
    return 0;
}

/** LUA on_craft (callbacks)
 * on_craft(function ref)
 **
 * Will make sure that the function ''ref'' gets called with the the crafting
 * character and a table with the recipes {(id, amount}) when a character
 * performs crafting.
 */
static int on_craft(lua_State *s)
{
    luaL_checktype(s, 1, LUA_TFUNCTION);
    ScriptManager::setCraftCallback(getScript(s));
    return 0;
}

/** LUA on_mapupdate (callbacks)
 * on_mapupdate(function ref)
 **
 * Will make sure that the function ''ref'' gets called with the the map id
 * as argument for each game tick and map.
 */
static int on_mapupdate(lua_State *s)
{
    luaL_checktype(s, 1, LUA_TFUNCTION);
    MapComposite::setUpdateCallback(getScript(s));
    return 0;
}


/** LUA_CATEGORY Creation and removal of stuff (creation)
 */

/** LUA npc_create (creation)
 * npc_create(string name, int spriteID, int gender, int x, int y, function talkfunct, function updatefunct)
 **
 * **Return value:** A handle to the created NPC.
 *
 * Creates a new NPC with the name ''name'' at the coordinates ''x'':''y''
 * which appears to the players with the appearence listed in their npcs.xml
 * under ''spriteID'' and the gender ''gender''. Every game tick the function
 * ''updatefunct'' is called with the handle of the NPC. When a character talks
 * to the NPC the function ''talkfunct'' is called with the NPC handle and the
 * character handle.
 *
 * For setting the gender you can use the constants defined in the
 * libmana-constants.lua:
 *
 * | 0 | GENDER_MALE         |
 * | 1 | GENDER_FEMALE       |
 * | 2 | GENDER_UNSPECIFIED  |
 */
static int npc_create(lua_State *s)
{
    const char *name = luaL_checkstring(s, 1);
    const int id = luaL_checkint(s, 2);
    const int gender = luaL_checkint(s, 3);
    const int x = luaL_checkint(s, 4);
    const int y = luaL_checkint(s, 5);

    if (!lua_isnoneornil(s, 6))
        luaL_checktype(s, 6, LUA_TFUNCTION);
    if (!lua_isnoneornil(s, 7))
        luaL_checktype(s, 7, LUA_TFUNCTION);

    MapComposite *m = checkCurrentMap(s);

    NpcComponent *npcComponent = new NpcComponent(id);

    Entity *npc = new Entity(OBJECT_NPC);
    auto *actorComponent = new ActorComponent(*npc);
    npc->addComponent(actorComponent);
    auto *beingComponent = new BeingComponent(*npc);
    npc->addComponent(beingComponent);
    npc->addComponent(npcComponent);
    // some health so it doesn't spawn dead
    beingComponent->setAttribute(*npc, ATTR_MAX_HP, 100);
    beingComponent->setAttribute(*npc, ATTR_HP, 100);
    beingComponent->setName(name);
    beingComponent->setGender(getGender(gender));

    actorComponent->setWalkMask(Map::BLOCKMASK_WALL | Map::BLOCKMASK_MONSTER |
                                Map::BLOCKMASK_CHARACTER);
    npc->setMap(m);
    actorComponent->setPosition(*npc, Point(x, y));

    if (lua_isfunction(s, 6))
    {
        lua_pushvalue(s, 6);
        npcComponent->setTalkCallback(luaL_ref(s, LUA_REGISTRYINDEX));
    }

    if (lua_isfunction(s, 7))
    {
        lua_pushvalue(s, 7);
        npcComponent->setUpdateCallback(luaL_ref(s, LUA_REGISTRYINDEX));
    }

    GameState::enqueueInsert(npc);
    lua_pushlightuserdata(s, npc);
    return 1;
}

/** LUA npc_enable (creation)
 * npc_disable(handle npc)
 **
 * Re-enables an NPC that got disabled before.
 */
static int npc_enable(lua_State *s)
{
    Entity *npc = checkNpc(s, 1);
    npc->getComponent<NpcComponent>()->setEnabled(true);
    GameState::enqueueInsert(npc);
    return 0;
}

/** LUA npc_disable (creation)
 * npc_disable(handle npc)
 **
 * Disable an NPC.
 */
static int npc_disable(lua_State *s)
{
    Entity *npc = checkNpc(s, 1);
    npc->getComponent<NpcComponent>()->setEnabled(false);
    GameState::remove(npc);
    return 0;
}

/** LUA monster_create (creation)
 * monster_create(int monsterID, int x, int y)
 * monster_create(string monstername, int x, int y)
 **
 * **Return value:** A handle to the created monster.
 *
 * Spawns a new monster of type ''monsterID'' or ''monstername'' on the current
 * map on the pixel coordinates ''x'':''y''.
 */
static int monster_create(lua_State *s)
{
    MonsterClass *monsterClass = checkMonsterClass(s, 1);
    const int x = luaL_checkint(s, 2);
    const int y = luaL_checkint(s, 3);
    MapComposite *m = checkCurrentMap(s);

    Entity *monster = new Entity(OBJECT_MONSTER);
    auto *actorComponent = new ActorComponent(*monster);
    monster->addComponent(actorComponent);
    monster->addComponent(new BeingComponent(*monster));
    monster->addComponent(new MonsterComponent(*monster, monsterClass));
    monster->setMap(m);
    actorComponent->setPosition(*monster, Point(x, y));
    GameState::enqueueInsert(monster);

    lua_pushlightuserdata(s, monster);
    return 1;
}

/** LUA monster_remove (creation)
 * monster_remove(handle monster)
 **
 * **Return value:** True if removing the monster suceeded.
 *
 * Remove the monster ''monster'' from the current map.
 */
static int monster_remove(lua_State *s)
{
    bool monsterRemoved = false;
    if (Entity *m = getMonster(s, 1))
    {
        GameState::remove(m);
        monsterRemoved = true;
    }
    lua_pushboolean(s, monsterRemoved);
    return 1;
}

/** LUA trigger_create (creation)
 * trigger_create(int x, int y, int width, int height, function trigger_function, int arg, bool once)
 **
 * Creates a new trigger area with the given ''height'' and ''width'' in pixels
 * at the map position ''x'':''y'' in pixels. When a being steps into this area
 * the function  ''trigger_function'' is called with the being handle and
 * ''arg'' as arguments. When ''once'' is false the function is called every
 * game tick the being is inside the    area. When ''once'' is true it is only
 * called again when the being leaves and reenters the area.
 */
static int trigger_create(lua_State *s)
{
    const int x = luaL_checkint(s, 1);
    const int y = luaL_checkint(s, 2);
    const int width = luaL_checkint(s, 3);
    const int height = luaL_checkint(s, 4);
    luaL_checktype(s, 5, LUA_TFUNCTION);
    const int id = luaL_checkint(s, 6);

    if (!lua_isboolean(s, 7))
    {
        luaL_error(s, "trigger_create called with incorrect parameters.");
        return 0;
    }

    Script *script = getScript(s);
    MapComposite *m = checkCurrentMap(s, script);

    const bool once = lua_toboolean(s, 7);

    Script::Ref function;
    lua_pushvalue(s, 5);
    script->assignCallback(function);
    lua_pop(s, 1);

    Entity *triggerEntity = new Entity(OBJECT_OTHER, m);

    ScriptAction *action = new ScriptAction(script, function, id);
    Rectangle r = { x, y, width, height };
    TriggerAreaComponent *area = new TriggerAreaComponent(r, action, once);

    triggerEntity->addComponent(area);

    LOG_INFO("Created script trigger at " << x << "," << y
             << " (" << width << "x" << height << ") id: " << id);

    bool ret = GameState::insertOrDelete(triggerEntity);
    lua_pushboolean(s, ret);
    return 1;
}

/** LUA effect_create (creation)
 * effect_create(int id, int x, int y)
 * effect_create(int id, being b)
 **
 * Triggers the effect ''id'' from the clients effects.xml
 * (particle and/or sound) at map location ''x'':''y'' or on being ''b''.
 * This has no effect on gameplay.
 *
 * **Warning:** Remember that clients might switch off particle effects for
 * performance reasons. Thus you should not use this for important visual
 * input.
 */
static int effect_create(lua_State *s)
{
    const int id = luaL_checkint(s, 1);

    if (lua_isuserdata(s, 2))
    {
        // being mode
        Entity *b = checkBeing(s, 2);
        Effects::show(id, b);
    }
    else
    {
        // positional mode
        int x = luaL_checkint(s, 2);
        int y = luaL_checkint(s, 3);
        MapComposite *m = checkCurrentMap(s);
        Effects::show(id, m, Point(x, y));
    }

    return 0;
}

/** LUA drop_item (creation)
 * drop_item(int x, int y, int id [, int number])
 * drop_item(int x, int y, string name[, int number])
 **
 * Creates an item stack on the floor.
 */
static int item_drop(lua_State *s)
{
    const int x = luaL_checkint(s, 1);
    const int y = luaL_checkint(s, 2);
    ItemClass *ic = checkItemClass(s, 3);
    const int number = luaL_optint(s, 4, 1);
    MapComposite *map = checkCurrentMap(s);

    Entity *item = Item::create(map, Point(x, y), ic, number);
    GameState::enqueueInsert(item);
    return 0;
}

/** LUA_CATEGORY Input and output (input)
 */

/** LUA npc_message (input)
 * npc_message(handle npc, handle character, string message)
 **
 * **Warning:** May only be called from an NPC talk function.
 *
 * Shows an NPC dialog box on the screen of character ''ch'' displaying the
 * string ''msg''. Idles the current thread until the user click "OK".
 */
static int npc_message(lua_State *s)
{
    Entity *npc = checkNpc(s, 1);
    Entity *q = checkCharacter(s, 2);
    const char *m = luaL_checkstring(s, 3);

    Script::Thread *thread = checkCurrentThread(s);

    MessageOut msg(GPMSG_NPC_MESSAGE);
    msg.writeInt16(npc->getComponent<ActorComponent>()->getPublicID());
    msg.writeString(m);
    gameHandler->sendTo(q, msg);

    thread->mState = Script::ThreadPaused;
    return lua_yield(s, 0);
}

/** LUA npc_choice (input)
 * npc_choice(handle npc, handle character, item1, item2, ... itemN)
 **
 * **Return value:** Number of the option the player selected (starting with 1).
 *
 * **Warning:** May only be called from an NPC talk function.
 *
 * Shows an NPC dialog box on the users screen with a number of dialog options
 * to choose from. Idles the current thread until the user selects one or
 * aborts the current   thread when the user clicks "cancel".
 *
 * Items are either strings or tables of strings (indices are ignored,
 * but presumed to be taken in order). So,
 * ''npc_choice(npc, ch, "A", {"B", "C", "D"}, "E")'' is the same as
 * ''npc_choice(npc, ch, "A", "B", "C", "D", "E")''.
 */
static int npc_choice(lua_State *s)
{
    Entity *npc = checkNpc(s, 1);
    Entity *q = checkCharacter(s, 2);

    Script::Thread *thread = checkCurrentThread(s);

    MessageOut msg(GPMSG_NPC_CHOICE);
    msg.writeInt16(npc->getComponent<ActorComponent>()->getPublicID());
    for (int i = 3, i_end = lua_gettop(s); i <= i_end; ++i)
    {
        if (lua_isstring(s, i))
        {
            msg.writeString(lua_tostring(s, i));
        }
        else if (lua_istable(s, i))
        {
            lua_pushnil(s);
            while (lua_next(s, i) != 0)
            {
                if (lua_isstring(s, -1))
                {
                    msg.writeString(lua_tostring(s, -1));
                }
                else
                {
                    luaL_error(s, "npc_choice called "
                               "with incorrect parameters.");
                    return 0;
                }
                lua_pop(s, 1);
            }
        }
        else
        {
            luaL_error(s, "npc_choice called with incorrect parameters.");
            return 0;
        }
    }
    gameHandler->sendTo(q, msg);

    thread->mState = Script::ThreadExpectingNumber;
    return lua_yield(s, 0);
}

/** LUA npc_ask_integer (input)
 * npc_ask_integer(handle npc, handle character, min_num, max_num, [default_num])
 **
 * **Return value:** The number the player entered into the field.
 *
 * **Warning:** May only be called from an NPC talk function.
 *
 * Shows a dialog box to the user which allows him to choose a number between
 * ''min_num'' and ''max_num''. If ''default_num'' is set this number will be
 * uses as default.  Otherwise ''min_num'' will be the default.
 */
static int npc_ask_integer(lua_State *s)
{
    Entity *npc = checkNpc(s, 1);
    Entity *q = checkCharacter(s, 2);
    int min = luaL_checkint(s, 3);
    int max = luaL_checkint(s, 4);
    int defaultValue = luaL_optint(s, 5, min);

    Script::Thread *thread = checkCurrentThread(s);

    MessageOut msg(GPMSG_NPC_NUMBER);
    msg.writeInt16(npc->getComponent<ActorComponent>()->getPublicID());
    msg.writeInt32(min);
    msg.writeInt32(max);
    msg.writeInt32(defaultValue);
    gameHandler->sendTo(q, msg);

    thread->mState = Script::ThreadExpectingNumber;
    return lua_yield(s, 0);
}

/** LUA npc_ask_string (input)
 * npc_ask_string(handle npc, handle character)
 **
 * **Return value:** The string the player entered.
 *
 * **Warning:** May only be called from an NPC talk function.
 *
 * Shows a dialog box to a user which allows him to enter a text.
 */
static int npc_ask_string(lua_State *s)
{
    Entity *npc = checkNpc(s, 1);
    Entity *q = checkCharacter(s, 2);

    Script::Thread *thread = checkCurrentThread(s);

    MessageOut msg(GPMSG_NPC_STRING);
    msg.writeInt16(npc->getComponent<ActorComponent>()->getPublicID());
    gameHandler->sendTo(q, msg);

    thread->mState = Script::ThreadExpectingString;
    return lua_yield(s, 0);
}

/** LUA npc_post (input)
 * npc_post(handle npc, handle character)
 **
 * Starts retrieving post. Better not try to use it so far.
 */
static int npc_post(lua_State *s)
{
    Entity *npc = checkNpc(s, 1);
    Entity *q = checkCharacter(s, 2);

    MessageOut msg(GPMSG_NPC_POST);
    msg.writeInt16(npc->getComponent<ActorComponent>()->getPublicID());
    gameHandler->sendTo(q, msg);

    return 0;
}

/** LUA being_say (input)
 * being_say(handle being, string message)
 **
 * Makes ''being'', which can be a character, monster or NPC, speak the string
 * ''message'' as if it was entered by a player in the chat bar.
 */
static int being_say(lua_State *s)
{
    Entity *being = checkBeing(s, 1);
    const char *message = luaL_checkstring(s, 2);
    GameState::sayAround(being, message);
    return 0;
}

/** LUA chat_message (input)
 * chat_message(handle character, string message)
 **
 * Outputs the string ''message'' in the chatlog of ''character'' which will
 * appear as a private message from "Server".
 */
static int chat_message(lua_State *s)
{
    Entity *being = checkBeing(s, 1);
    const char *message = luaL_checkstring(s, 2);

    GameState::sayTo(being, nullptr, message);
    return 0;
}

/** LUA announce (input)
 * announce(string message [, string sender])
 **
 * Sends a global announce with the given ''message'' and ''sender''. If no
 * ''sender'' is passed "Server" will be used as sender.
 */
static int announce(lua_State *s)
{
    const char *message = luaL_checkstring(s, 1);
    const char *sender = luaL_optstring(s, 2, "Server");

    MessageOut msg(GAMSG_ANNOUNCE);
    msg.writeString(message);
    msg.writeInt16(0); // Announce from server so id = 0
    msg.writeString(sender);
    accountHandler->send(msg);
    return 0;
}


/** LUA_CATEGORY Inventory interaction (inventory)
 */

/** LUA npc_trade (inventory)
 * npc_trade(handle npc,
 *           handle character,
 *           bool mode,
 *           {int item1id, int item1amount, int item1cost}, ...,
 *           {int itemNid, int itemNamount, int itemNcost})
 * npc_trade(handle npc,
 *           handle character,
 *           bool mode,
 *           {string item1name, int item1amount, int item1cost}, ...,
 *           {string itemNname, int itemNamount, int itemNcost})
 **
 * FIXME: Move into a seperate file
 * Opens a trade window for ''character'' while talking with ''npc''. ''mode'' is true for selling and false for buying. You have to set each items the NPC is buying/selling,    the cost and the maximum amount in {}.
 *
 * **Note:** If the fourth parameters (table type) is omitted or invalid, and the mode set to sell (true),
 * the whole player inventory is then sellable.
 *
 * **N.B.:** Be sure to put a ''value'' (item cost) parameter in your items.xml to permit the player to sell it when using this option.
 *
 * **Return values:**
 *   * **0** when a trade has been started
 *   * **1** when there is no buy/sellable items
 *   * **2** in case of errors.
 *
 * **Examples:**
 * <code lua npc_trade.lua>
 *     -- "A buy sample."
 *     local buycase = npc_trade(npc, ch, false, { {"Sword", 10, 20}, {"Bow", 10, 30}, {"Dagger", 10, 50} })
 *     if buycase == 0 then
 *       npc_message(npc, ch, "What do you want to buy?")
 *     elseif buycase == 1 then
 *       npc_message(npc, ch, "I've got no items to sell.")
 *     else
 *       npc_message(npc, ch, "Hmm, something went wrong... Ask a scripter to fix the buying mode!")
 *     end
 *
 * -- ...
 *
 *    -- "Example: Let the player sell only pre-determined items."
 *    local sellcase = npc_trade(npc, ch, true, { {"Sword", 10, 20}, {"Bow", 10, 30},
 *                      {"Dagger", 10, 200}, {"Knife", 10, 300}, {"Arrow", 10, 500}, {"Cactus Drink", 10, 25} })
 *     if sellcase == 0 then
 *       npc_message(npc, ch, "Here we go:")
 *     elseif sellcase == 1 then
 *       npc_message(npc, ch, "I'm not interested by your items.")
 *     else
 *       npc_message(npc, ch, "Hmm, something went wrong... Ask a scripter to fix me!")
 *     end
 *
 * -- ...
 *
 *     -- "Example: Let the player sell every item with a 'value' parameter in the server's items.xml file
 *     local sellcase = npc_trade(npc, ch, true)
 *     if sellcase == 0 then
 *       npc_message(npc, ch, "Ok, what do you want to sell:")
 *     elseif sellcase == 1 then
 *       npc_message(npc, ch, "I'm not interested by any of your items.")
 *     else
 *       npc_message(npc, ch, "Hmm, something went wrong... Ask a scripter to fix this!")
 *     end
 * </code>
 */
static int npc_trade(lua_State *s)
{
    Entity *npc = checkNpc(s, 1);
    Entity *q = checkCharacter(s, 2);
    if (!lua_isboolean(s, 3))
    {
        luaL_error(s, "npc_trade called with incorrect parameters.");
        return 0;
    }

    bool sellMode = lua_toboolean(s, 3);
    BuySell *t = new BuySell(q, sellMode);
    if (!lua_istable(s, 4))
    {
        if (sellMode)
        {
            // Can sell everything
            if (!t->registerPlayerItems())
            {
                // No items to sell in player inventory
                t->cancel();
                lua_pushinteger(s, 1);
                return 1;
            }

            if (t->start(npc))
            {
                lua_pushinteger(s, 0);
                return 1;
            }
            else
            {
                lua_pushinteger(s, 1);
                return 1;
            }
        }
        else
        {
            raiseWarning(s, "npc_trade[Buy] called with invalid "
                         "or empty items table parameter.");
            t->cancel();
            lua_pushinteger(s, 2);
            return 1;
        }
    }

    int nbItems = 0;

    lua_pushnil(s);
    while (lua_next(s, 4))
    {
        if (!lua_istable(s, -1))
        {
            raiseWarning(s, "npc_trade called with invalid "
                         "or empty items table parameter.");
            t->cancel();
            lua_pushinteger(s, 2);
            return 1;
        }

        int v[3];
        for (int i = 0; i < 3; ++i)
        {
            lua_rawgeti(s, -1, i + 1);
            if (i == 0) // item id or name
            {
                ItemClass *it = getItemClass(s, -1);

                if (!it)
                {
                    raiseWarning(s, "npc_trade called with incorrect "
                                 "item id or name.");
                    t->cancel();
                    lua_pushinteger(s, 2);
                    return 1;
                }
                v[0] = it->getDatabaseID();
            }
            else if (!lua_isnumber(s, -1))
            {
                raiseWarning(s, "npc_trade called with incorrect parameters "
                             "in item table.");
                t->cancel();
                lua_pushinteger(s, 2);
                return 1;
            }
            else
            {
                v[i] = lua_tointeger(s, -1);
            }
            lua_pop(s, 1);
        }
        if (t->registerItem(v[0], v[1], v[2]))
            nbItems++;
        lua_pop(s, 1);
    }

    if (nbItems == 0)
    {
        t->cancel();
        lua_pushinteger(s, 1);
        return 1;
    }
    if (t->start(npc))
    {
        lua_pushinteger(s, 0);
        return 1;
    }
    else
    {
        lua_pushinteger(s, 1);
        return 1;
    }
}

/** LUA chr_inv_count (inventory)
 * chr_inv_count(handle character, bool inInventory, bool inEquipment, int id1, ..., int idN)
 * chr_inv_count(handle character, bool inInventory, bool inEquipment, string name1, ..., string nameN)
 **
 * The boolean values ''inInventory'' and ''inEquipment'' make possible to
 * select whether equipped or carried items must be counted.
 *
 * **Return values:** A number of integers with the amount of items ''id'' or
 * ''name'' carried or equipped by the ''character''.
 */
static int chr_inv_count(lua_State *s)
{
    Entity *q = checkCharacter(s, 1);
    if (!lua_isboolean(s, 2) || !lua_isboolean(s, 3))
    {
        luaL_error(s, "chr_inv_count called with incorrect parameters.");
        return 0;
    }

    bool inInventory = lua_toboolean(s, 2);
    bool inEquipment = lua_toboolean(s, 3);

    int nb_items = lua_gettop(s) - 3;
    Inventory inv(q);

    int nb = 0;
    for (int i = 4; i < nb_items + 4; ++i)
    {
        ItemClass *it = checkItemClass(s, i);
        nb = inv.count(it->getDatabaseID(), inInventory, inEquipment);
        lua_pushinteger(s, nb);
    }
    return nb_items;
}

/** LUA chr_inv_change (inventory)
 * chr_inv_change(handle character, int id1, int number1, ..., int idN, numberN)
 * chr_inv_change(handle character, string name1, int number1, ..., string nameN, numberN)
 **
 * **Return value:** Boolean true on success, boolean false on failure.
 *
 * Changes the number of items with the item ID ''id'' or ''name'' owned by
 * ''character'' by ''number''. You can change any number of items with this
 * function by passing         multiple ''id'' or ''name'' and ''number'' pairs.
 * A failure can be caused by trying to take items the character doesn't possess.
 *
 * **Warning:** When one of the operations fails the following operations are
 * ignored but these before are executed. For that reason you should always
 * check if the character     possesses items you are taking away using
 * chr_inv_count.
 */
static int chr_inv_change(lua_State *s)
{
    Entity *q = checkCharacter(s, 1);
    int nb_items = (lua_gettop(s) - 1) / 2;
    Inventory inv(q);
    for (int i = 0; i < nb_items; ++i)
    {
        if (!lua_isnumber(s, i * 2 + 3))
        {
            luaL_error(s, "chr_inv_change called with "
                       "incorrect parameters.");
            return 0;
        }

        int nb = lua_tointeger(s, i * 2 + 3);
        ItemClass *ic = checkItemClass(s, i * 2 + 2);
        int id = ic->getDatabaseID();
        if (nb < 0)
        {
            // Removing too much item is a success as for the scripter's
            // point of view. We log it anyway.
            nb = inv.remove(id, -nb);
            if (nb)
            {
                LOG_WARN("chr_inv_change() removed more items than owned: "
                     << "character: "
                     << q->getComponent<BeingComponent>()->getName()
                     << " item id: " << id);
            }
        }
        else
        {
            nb = inv.insert(id, nb);
            if (nb)
            {
                const Point &position =
                        q->getComponent<ActorComponent>()->getPosition();
                Entity *item = Item::create(q->getMap(), position, ic, nb);
                GameState::enqueueInsert(item);
            }
        }
    }
    lua_pushboolean(s, 1);
    return 1;
}

/** LUA chr_get_inventory (inventory)
 * chr_get_inventory(character): table[]{slot, item id, name, amount}
 **
 * used to get a full view of a character's inventory.
 * This is not the preferred way to know whether an item is in the character's inventory:
 * Use chr_inv_count for simple cases.
 *
 * **Return value:** A table containing all the info about the character's inventory.
 * Empty slots are not listed.
 *
 * **Example of use:**
 * <code lua>
 * local inventory_table = chr_get_inventory(ch)
 * for i = 1, #inventory_table do
 *     item_message = item_message.."\n"..inventory_table[i].slot..", "
 *         ..inventory_table[i].id..", "..inventory_table[i].name..", "
 *         ..inventory_table[i].amount
 * end
 * </code>
 */
static int chr_get_inventory(lua_State *s)
{
    Entity *q = checkCharacter(s, 1);

    // Create a lua table with the inventory ids.
    const InventoryData invData = q->getComponent<CharacterComponent>()
            ->getPossessions().getInventory();

    lua_newtable(s);
    int firstTableStackPosition = lua_gettop(s);
    int tableIndex = 1;

    for (InventoryData::const_iterator it = invData.begin(),
        it_end = invData.end(); it != it_end; ++it)
    {
        if (!it->second.itemId || !it->second.amount)
            continue;

        // Create the sub-table (value of the main one)
        lua_createtable(s, 0, 4);
        int subTableStackPosition = lua_gettop(s);
        // Stores the item info in it.
        lua_pushliteral(s, "slot");
        lua_pushinteger(s, it->first); // The slot id
        lua_settable(s, subTableStackPosition);

        lua_pushliteral(s, "id");
        lua_pushinteger(s, it->second.itemId);
        lua_settable(s, subTableStackPosition);

        lua_pushliteral(s, "name");
        push(s, itemManager->getItem(it->second.itemId)->getName());
        lua_settable(s, subTableStackPosition);

        lua_pushliteral(s, "amount");
        lua_pushinteger(s, it->second.amount);
        lua_settable(s, subTableStackPosition);

        // Add the sub-table as value of the main one.
        lua_rawseti(s, firstTableStackPosition, tableIndex);
        ++tableIndex;
    }

    return 1;
}

/** LUA chr_get_equipment (inventory)
 * chr_get_equipment(character): table[](slot, item id, name)}
 **
 * Used to get a full view of a character's equipment.
 * This is not the preferred way to know whether an item is equipped:
 * Use chr_inv_count for simple cases.
 *
 * **Return value:** A table containing all the info about the character's equipment.
 * Empty slots are not listed.
 *
 * **Example of use:**
 * <code lua>
 * local equipment_table = chr_get_equipment(ch)
 * for i = 1, #equipment_table do
 *     item_message = item_message.."\n"..equipment_table[i].slot..", "
 *         ..equipment_table[i].id..", "..equipment_table[i].name
 * end
 * </code>
 */
static int chr_get_equipment(lua_State *s)
{
    Entity *q = checkCharacter(s, 1);

    // Create a lua table with the inventory ids.
    const EquipData equipData = q->getComponent<CharacterComponent>()
            ->getPossessions().getEquipment();

    lua_newtable(s);
    int firstTableStackPosition = lua_gettop(s);
    int tableIndex = 1;

    std::set<unsigned> itemInstances;

    for (EquipData::const_iterator it = equipData.begin(),
        it_end = equipData.end(); it != it_end; ++it)
    {
        if (!it->second.itemId || !it->second.itemInstance)
            continue;

        // Only count multi-slot items once.
        if (!itemInstances.insert(it->second.itemInstance).second)
            continue;

        // Create the sub-table (value of the main one)
        lua_createtable(s, 0, 3);
        int subTableStackPosition = lua_gettop(s);
        // Stores the item info in it.
        lua_pushliteral(s, "slot");
        lua_pushinteger(s, it->first); // The slot id
        lua_settable(s, subTableStackPosition);

        lua_pushliteral(s, "id");
        lua_pushinteger(s, it->second.itemId);
        lua_settable(s, subTableStackPosition);

        lua_pushliteral(s, "name");
        push(s, itemManager->getItem(it->second.itemId)->getName());
        lua_settable(s, subTableStackPosition);

        // Add the sub-table as value of the main one.
        lua_rawseti(s, firstTableStackPosition, tableIndex);
        ++tableIndex;
    }

    return 1;
}

/** LUA chr_equip_slot (inventory)
 * chr_equip_slot(handle character, int slot)
 **
 * Makes the character equip the item in the given inventory slot.
 */
static int chr_equip_slot(lua_State *s)
{
    Entity *ch = checkCharacter(s, 1);
    int inventorySlot = luaL_checkint(s, 2);

    Inventory inv(ch);
    lua_pushboolean(s, inv.equip(inventorySlot));
    return 1;
}

/** LUA chr_equip_item (inventory)
 * chr_equip_item(handle character, int item_id)
 * chr_equip_item(handle character, string item_name)
 **
 * Makes the character equip the item id when it's existing
 * in the player's inventory.
 *
 * **Return value:** true if equipping suceeded. false otherwise.
 */
static int chr_equip_item(lua_State *s)
{
    Entity *ch = checkCharacter(s, 1);
    ItemClass *it = checkItemClass(s, 2);

    Inventory inv(ch);

    int inventorySlot = inv.getFirstSlot(it->getDatabaseID());
    bool success = false;

    if (inventorySlot > -1)
        success = inv.equip(inventorySlot);

    lua_pushboolean(s, success);
    return 1;
}

/** LUA chr_unequip_slot (inventory)
 * chr_unequip_slot(handle character, int slot)
 **
 * Makes the character unequip the item in the given equipment slot.
 *
 * **Return value:** true upon success. false otherwise.
 */
static int chr_unequip_slot(lua_State *s)
{
    Entity *ch = checkCharacter(s, 1);
    int equipmentSlot = luaL_checkint(s, 2);

    Inventory inv(ch);

    lua_pushboolean(s, inv.unequip(inv.getSlotItemInstance(equipmentSlot)));
    return 1;
}

/** LUA chr_unequip_item (inventory)
 * chr_unequip_item(handle character, int item_id)
 * chr_unequip_item(handle character, string item_name)
 **
 * Makes the character unequip the item(s) corresponding to the id
 * when it's existing in the player's equipment.
 *
 * **Return value:** true when every item were unequipped from equipment.
 */
static int chr_unequip_item(lua_State *s)
{
    Entity *ch = checkCharacter(s, 1);
    ItemClass *it = checkItemClass(s, 2);

    Inventory inv(ch);
    lua_pushboolean(s, inv.unequipItem(it->getDatabaseID()));
    return 1;
}

/** LUA_CATEGORY Character and being interaction (being)
 */

/** LUA chr_get_quest (being)
 * chr_get_quest(handle character, string name)
 **
 * **Return value:** The quest variable named ''name'' for the given character.
 *
 * **Warning:** May only be called from an NPC talk function.
 *
 */
static int chr_get_quest(lua_State *s)
{
    Entity *q = checkCharacter(s, 1);
    const char *name = luaL_checkstring(s, 2);
    luaL_argcheck(s, name[0] != 0, 2, "empty variable name");

    Script::Thread *thread = checkCurrentThread(s);

    std::string value;
    bool res = getQuestVar(q, name, value);
    if (res)
    {
        push(s, value);
        return 1;
    }
    QuestCallback *f = new QuestThreadCallback(&LuaScript::getQuestCallback,
                                               getScript(s));
    recoverQuestVar(q, name, f);

    thread->mState = Script::ThreadExpectingString;
    return lua_yield(s, 0);
}

/** LUA chr_set_quest (being)
 * chr_set_quest(handle character, string name, string value)
 **
 * Sets the quest variable named ''name'' for the given  character to the value
 * ''value''.
 */
static int chr_set_quest(lua_State *s)
{
    Entity *q = checkCharacter(s, 1);
    const char *name = luaL_checkstring(s, 2);
    const char *value = luaL_checkstring(s, 3);
    luaL_argcheck(s, name[0] != 0, 2, "empty variable name");

    setQuestVar(q, name, value);
    return 0;
}

/** LUA chr_set_special_recharge_speed (being)
 * chr_set_special_recharge_speed(handle ch, int specialid, int new_speed)
 * chr_set_special_recharge_speed(handle ch, string specialname, int new_speed)
 **
 * Sets the recharge speed of the special to a new value for the character.
 *
 * **Note:** When passing the ''specialname'' as parameter make sure that it is
 * formatted in this way: <setname>_<specialname> (for eg. "Magic_Healingspell").
 */
static int chr_set_special_recharge_speed(lua_State *s)
{
    Entity *c = checkCharacter(s, 1);
    const int special = checkSpecial(s, 2);
    const int speed = luaL_checkint(s, 3);

    if (!c->getComponent<CharacterComponent>()
            ->setSpecialRechargeSpeed(special, speed))
    {
        luaL_error(s,
                   "chr_set_special_recharge_speed called with special "
                   "that is not owned by character.");
    }
    return 0;
}

/** LUA chr_get_special_recharge_speed (being)
 * chr_get_special_recharge_speed(handle ch, int specialid)
 * chr_get_special_recharge_speed(handle ch, string specialname)
 **
 * **Return value:** The current recharge speed of the special that is owned by
 * the character ''ch''.
 *
 * **Note:** When passing the ''specialname'' as parameter make sure that it is
 * formatted in this way: <setname>_<specialname> (for eg. "Magic_Healingspell").
 */
static int chr_get_special_recharge_speed(lua_State *s)
{
    Entity *c = checkCharacter(s, 1);
    const int special = checkSpecial(s, 2);

    auto *characterComponent = c->getComponent<CharacterComponent>();

    SpecialMap::iterator it = characterComponent->findSpecial(special);

    luaL_argcheck(s, it != characterComponent->getSpecialEnd(), 2,
                  "character does not have special");

    lua_pushinteger(s, it->second.rechargeSpeed);
    return 1;
}

/** LUA chr_set_special_mana (being)
 * chr_set_special_mana(handle ch, int specialid, int new_mana)
 * chr_set_special_mana(handle ch, string specialname, int new_mana)
 **
 * Sets the mana (recharge status) of the special to a new value for the
 * character.
 *
 * **Note:** When passing the ''specialname'' as parameter make sure that it is
 * formatted in this way: <setname>_<specialname> (for eg. "Magic_Healingspell").
 */
static int chr_set_special_mana(lua_State *s)
{
    Entity *c = checkCharacter(s, 1);
    const int special = checkSpecial(s, 2);
    const int mana = luaL_checkint(s, 3);
    if (!c->getComponent<CharacterComponent>()->setSpecialMana(special, mana))
    {
        luaL_error(s,
                   "chr_set_special_mana called with special "
                   "that is not owned by character.");
    }
    return 0;
}

/** LUA chr_get_special_mana (being)
 * chr_get_special_mana(handle ch, int specialid)
 * chr_get_special_mana(handle ch, string specialname)
 **
 * **Return value:** The mana (recharge status) of the special that is owned by
 * the character ''ch''.
 *
 * **Note:** When passing the ''specialname'' as parameter make sure that it is
 * formatted in this way: <setname>_<specialname> (for eg. "Magic_Healingspell").
 */
static int chr_get_special_mana(lua_State *s)
{
    Entity *c = checkCharacter(s, 1);
    auto *characterComponent = c->getComponent<CharacterComponent>();
    const int special = checkSpecial(s, 2);
    SpecialMap::iterator it = characterComponent->findSpecial(special);
    luaL_argcheck(s, it != characterComponent->getSpecialEnd(), 2,
                  "character does not have special");
    lua_pushinteger(s, it->second.currentMana);
    return 1;
}

/** LUA being_walk (being)
 * being_walk(handle being, int pixelX, int pixelY [, int walkSpeed])
 **
 * Set the desired destination in pixels for the **'being'**.
 *
 * The optional **'WalkSpeed'** is to be given in tiles per second. The average
 * speed is 6.0 tiles per second. If no speed is given the default speed of the
 * being is used.
 */
static int being_walk(lua_State *s)
{
    Entity *being = checkBeing(s, 1);
    const int x = luaL_checkint(s, 2);
    const int y = luaL_checkint(s, 3);

    auto *beingComponent = being->getComponent<BeingComponent>();

    beingComponent->setDestination(*being, Point(x, y));

    if (lua_gettop(s) >= 4)
    {
        const double speedTps = luaL_checknumber(s, 4);
        beingComponent->setAttribute(*being, ATTR_MOVE_SPEED_TPS, speedTps);
        const double modifiedSpeedTps =
                beingComponent->getModifiedAttribute(ATTR_MOVE_SPEED_TPS);
        beingComponent->setAttribute(*being, ATTR_MOVE_SPEED_RAW,
                                     utils::tpsToRawSpeed(modifiedSpeedTps));
    }

    return 0;
}

/** LUA being_damage (being)
 * being_damage(handle being, int damage, int delta,
 *              int accuracy, int type, int element)
 * being_damage(handle being, int damage, int delta, int accuracy,
 *              int type, int element, handle source)
 * being_damage(handle being, int damage, int delta, int accuracy,
 *              int type, int element, handle source, int skill)
 * being_damage(handle being, int damage, int delta, int accuracy,
 *              int type, int element, handle source, string skillname)
 **
 * Inflicts damage to ''being''. The severity of the attack is between
 * ''damage'' and (''damage'' + ''delta'') and is calculated using the normal [[damage calculation]] rules. The being has a chance to [[hitting and dodging|dodge the attack]] with its [[attributes|agility attribute]]. The ''accuracy'' decides how hard this is. If ''source'' is provided the attack is handled as if the ''source'' triggered the damage. If ''skill'' is given the ''owner'' can also recieve xp for the attack. The ''skill'' should be defined in the [[skills.xml|skills.xml]]. If the skill is provided as string (''skillname'') you have to use this format: <setname>_<skillname>. So for example: "Weapons_Unarmed"
 *
 * ''type'' affects which kind of armor and character attributes reduce the
 * damage. It can be one of the following values:
 * | 0 | DAMAGE_PHYSICAL  |
 * | 1 | DAMAGE_MAGICAL  |
 * | 2 | DAMAGE_OTHER  |
 *
 * ''element'' decides how the [[element system]] changes the damage. The
 * following values are possible:
 * | 0 | ELEMENT_NEUTRAL  |
 * | 1 | ELEMENT_FIRE  |
 * | 2 | ELEMENT_WATER  |
 * | 3 | ELEMENT_EARTH  |
 * | 4 | ELEMENT_AIR  |
 * | 5 | ELEMENT_LIGHTNING  |
 * | 6 | ELEMENT_METAL  |
 * | 7 | ELEMENT_WOOD  |
 * | 8 | ELEMENT_ICE  |
 *
 * **Return Value**: Actual HP reduction resulting from the attack.
 */
static int being_damage(lua_State *s)
{
    Entity *being = checkBeing(s, 1);

    if (!being->canFight())
    {
        luaL_error(s, "being_damage called with victim that cannot fight");
        return 0;
    }

    Damage dmg;
    dmg.base = luaL_checkint(s, 2);
    dmg.delta = luaL_checkint(s, 3);
    dmg.cth = luaL_checkint(s, 4);
    dmg.type = (DamageType)luaL_checkint(s, 5);
    dmg.element = (Element)luaL_checkint(s, 6);
    Entity *source = 0;
    if (lua_gettop(s) >= 7)
    {
        source = checkBeing(s, 7);

        if (!source->canFight())
        {
            luaL_error(s, "being_damage called with source that cannot fight");
            return 0;
        }
    }
    if (lua_gettop(s) >= 8)
    {
        dmg.skill = checkSkill(s, 8);
    }
    being->getComponent<CombatComponent>()->damage(*being, source, dmg);

    return 0;
}

/** LUA being_heal (being)
 * being_heal(handle being[, int value])
 **
 * Restores ''value'' lost hit points to ''being''. Value can be omitted to
 * restore the being to full hit points.
 *
 * While you can (ab)use this function to hurt a being by using a negative
 * value you should rather use being_damage for this purpose.
 */
static int being_heal(lua_State *s)
{
    Entity *being = checkBeing(s, 1);

    if (lua_gettop(s) == 1) // when there is only one argument
    {
        being->getComponent<BeingComponent>()->heal(*being);
    }
    else
    {
        being->getComponent<BeingComponent>()->heal(*being,
                                                    luaL_checkint(s, 2));
    }

    return 0;
}

/** LUA being_get_name (being)
 * being_get_name(handle being)
 **
 * **Return value:** Name of the being.
 */
static int being_get_name(lua_State *s)
{
    Entity *being = checkBeing(s, 1);
    push(s, being->getComponent<BeingComponent>()->getName());
    return 1;
}

/** LUA being_type (being)
 * being_type(handle being)
 **
 * **Return value:** Type of the given being. These type constants are defined
 * in libmana-constants.lua:
 *
 * | 0 | TYPE_ITEM      |
 * | 1 | TYPE_ACTOR     |
 * | 2 | TYPE_NPC       |
 * | 3 | TYPE_MONSTER   |
 * | 4 | TYPE_CHARACTER |
 * | 5 | TYPE_EFFECT    |
 * | 6 | TYPE_OTHER     |
*/
static int being_type(lua_State *s)
{
    Entity *being = checkBeing(s, 1);
    lua_pushinteger(s, being->getType());
    return 1;
}

/** LUA being_get_action (being)
 * being_get_action(handle being)
 **
 * **Return value:** Current action of the given being. These action constants
 * are defined in libmana-constants.lua:
 *
 * | 0 | ACTION_STAND  |
 * | 1 | ACTION_WALK   |
 * | 2 | ACTION_ATTACK |
 * | 3 | ACTION_SIT    |
 * | 4 | ACTION_DEAD   |
 * | 5 | ACTION_HURT   |
 */
static int being_get_action(lua_State *s)
{
    Entity *being = checkBeing(s, 1);
    lua_pushinteger(s, being->getComponent<BeingComponent>()->getAction());
    return 1;
}

/** LUA being_set_action (being)
 * being_set_action(handle being, int action)
 **
 * Sets the current action for the being.
 */
static int being_set_action(lua_State *s)
{
    Entity *being = checkBeing(s, 1);
    int act = luaL_checkint(s, 2);
    being->getComponent<BeingComponent>()->setAction(*being,
                                                     (BeingAction) act);
    return 0;
}

/** LUA being_get_direction (being)
 * being_get_direction(handle being)
 **
 * **Return value:** Current direction of the given being. These direction
 * constants are defined in libmana-constants.lua:
 *
 * | 0 | DIRECTION_DEFAULT |
 * | 1 | DIRECTION_UP      |
 * | 2 | DIRECTION_DOWN    |
 * | 3 | DIRECTION_LEFT    |
 * | 4 | DIRECTION_RIGHT   |
 * | 5 | DIRECTION_INVALID |
 */
static int being_get_direction(lua_State *s)
{
    Entity *being = checkBeing(s, 1);
    lua_pushinteger(s, being->getComponent<BeingComponent>()->getDirection());
    return 1;
}

/** LUA being_set_direction (being)
 * being_set_direction(handle being, int direction)
 **
 * Sets the current direction of the given being. Directions are same as in
 * ''being_get_direction''.
 */
static int being_set_direction(lua_State *s)
{
    Entity *being = checkBeing(s, 1);
    BeingDirection dir = (BeingDirection) luaL_checkint(s, 2);
    being->getComponent<BeingComponent>()->setDirection(*being, dir);
    return 0;
}

/** LUA being_set_walkmask (being)
 * being_set_walkmask(handle being, string mask)
 **
 * Sets the walkmasks of a being. The mask is a set of characters which stand
 * for different collision types.
 *
 * | w | Wall      |
 * | c | Character |
 * | m | Monster   |
 *
 * This means being_set_walkmask(being, "wm") will prevent the being from
 * walking over walls and monsters.
 */
static int being_set_walkmask(lua_State *s)
{
   Entity *being = checkBeing(s, 1);
   const char *stringMask = luaL_checkstring(s, 2);
   unsigned char mask = 0x00;
   if (strchr(stringMask, 'w'))
       mask |= Map::BLOCKMASK_WALL;
   else if (strchr(stringMask, 'c'))
       mask |= Map::BLOCKMASK_CHARACTER;
   else if (strchr(stringMask, 'm'))
       mask |= Map::BLOCKMASK_MONSTER;
   being->getComponent<ActorComponent>()->setWalkMask(mask);
   return 0;
}

/** LUA being_get_walkmask (being)
 * being_get_walkmask(handle being)
 **
 * **Return value:** The walkmask of the being formatted as string. (See
 * [[scripting#get_item_class|being_set_walkmask]])
 */
static int being_get_walkmask(lua_State *s)
{
   Entity *being = checkBeing(s, 1);
   const unsigned char mask =
           being->getComponent<ActorComponent>()->getWalkMask();
   luaL_Buffer buffer;
   luaL_buffinit(s, &buffer);
   if (mask & Map::BLOCKMASK_WALL)
       luaL_addstring(&buffer, "w");
   if (mask & Map::BLOCKMASK_CHARACTER)
       luaL_addstring(&buffer, "c");
   if (mask & Map::BLOCKMASK_MONSTER)
       luaL_addstring(&buffer, "m");
   luaL_pushresult(&buffer);
   return 1;
}

/** LUA chr_warp (being)
 * chr_warp(handle character, int mapID, int posX, int posY)
 * chr_warp(handle character, string mapName, int posX, int posY)
 **
 * Teleports the ''character'' to the position ''posX'':''posY'' on the map
 * with the ID number ''mapID'' or name ''mapName''. The ''mapID'' can be
 * substituted by ''nil'' to warp the ''character'' to a new position on the
 * current map.
 */
static int chr_warp(lua_State *s)
{
    Entity *q = checkCharacter(s, 1);
    int x = luaL_checkint(s, 3);
    int y = luaL_checkint(s, 4);

    bool b = lua_isnil(s, 2);
    if (!(b || lua_isnumber(s, 2) || lua_isstring(s, 2)))
    {
        luaL_error(s, "chr_warp called with incorrect parameters.");
        return 0;
    }
    MapComposite *m;
    if (b)
    {
        m = checkCurrentMap(s);
    }
    else if (lua_isnumber(s, 2))
    {
        m = MapManager::getMap(lua_tointeger(s, 2));
        luaL_argcheck(s, m, 2, "invalid map id");
    }
    else
    {
        m = MapManager::getMap(lua_tostring(s, 2));
        luaL_argcheck(s, m, 2, "invalid map name");
    }

    Map *map = m->getMap();

    // If the wanted warp place is unwalkable
    if (!map->getWalk(x / map->getTileWidth(), y / map->getTileHeight()))
    {
        int c = 50;
        LOG_INFO("chr_warp called with a non-walkable place.");
        do
        {
            x = rand() % map->getWidth();
            y = rand() % map->getHeight();
        } while (!map->getWalk(x, y) && --c);
        x *= map->getTileWidth();
        y *= map->getTileHeight();
    }
    GameState::enqueueWarp(q, m, Point(x, y));

    return 0;
}

/** LUA posX (being)
 * posX(handle being)
 **
 * **Return value:** The horizontal position of the ''being'' in pixels
 * measured from the left border of the map it is currently on.
 */
static int posX(lua_State *s)
{
    Entity *being = checkBeing(s, 1);
    lua_pushinteger(s, being->getComponent<ActorComponent>()->getPosition().x);
    return 1;
}

/** LUA posY (being)
 * posY(handle being)
 **
 * **Return value:** The vertical position of the ''being'' in pixels measured
 * from the upper border of the map it is currently on.
 */
static int posY(lua_State *s)
{
    Entity *being = checkBeing(s, 1);
    lua_pushinteger(s, being->getComponent<ActorComponent>()->getPosition().y);
    return 1;
}

/** LUA being_get_base_attribute (being)
 * being_get_base_attribute(handle being, int attribute_id)
 **
 * Set the value of the being's ''base attribute'' to the 'new_value' parameter
 * given. (It can be negative).
 */
static int being_get_base_attribute(lua_State *s)
{
    Entity *being = checkBeing(s, 1);
    int attr = luaL_checkint(s, 2);
    luaL_argcheck(s, attr > 0, 2, "invalid attribute id");

    lua_pushinteger(s, being->getComponent<BeingComponent>()
                    ->getAttributeBase(attr));
    return 1;
}

/** LUA being_set_base_attribute (being)
 * being_set_base_attribute(handle being, int attribute_id, double new_value)
 **
 * **Return value:** Returns the double value of the being's ''base attribute''.
 */
static int being_set_base_attribute(lua_State *s)
{
    Entity *being = checkBeing(s, 1);
    int attr = luaL_checkint(s, 2);
    double value = luaL_checknumber(s, 3);

    being->getComponent<BeingComponent>()->setAttribute(*being, attr, value);
    return 0;
}

/** being_get_modified_attribute (being)
 * being_get_modified_attribute(handle being, int attribute_id)
 **
 * *Return value:** Returns the double value of the being's
 * ''modified attribute''.
 *
 * The modified attribute is equal to the base attribute + currently applied
 * modifiers.
 *
 * To get to know how to configure and create modifiers, you can have a look at
 * the [[attributes.xml]] file and at the [[#being_apply_attribute_modifier]]()
 * and [[#being_remove_attribute_modifier]]() lua functions.
 *
 * Note also that items, equipment, and monsters attacks can cause attribute
 * modifiers.
 *
 * FIXME: This functions about applying and removing modifiers are still WIP,
 * because some simplifications and renaming could occur.
 */
static int being_get_modified_attribute(lua_State *s)
{
    Entity *being = checkBeing(s, 1);
    int attr = luaL_checkint(s, 2);
    luaL_argcheck(s, attr > 0, 2, "invalid attribute id");

    const double value =
            being->getComponent<BeingComponent>()->getModifiedAttribute(attr);
    lua_pushinteger(s, value);
    return 1;
}

/** LUA being_apply_attribute_modifier (being)
 * being_apply_attribute_modifier(handle being, int attribute_id, double value,
 *                                unsigned int layer, [unsigned short duration,
 *                                [unsigned int effect_id]])
 **
 * **Parameters description:** \\
 *   * **value** (double): The modifier value (can be negative).
 *   * **layer** (unsigned int): The layer or level of the modifier.
 *     As modifiers are stacked on an attribute, the layer determines
 *     where the modifier will be inserted. Also, when adding a modifier,
 *     all the modifiers with an higher ayer value will also be recalculated.
 *   * **duration** (unsigned short): The modifier duration in ticks((A tick is
 *     equal to 100ms.)). If set to 0, the modifier is permanent.
 *   * **effect_id** (unsigned int): Set and keep that parameter when you want
 *     to retrieve the exact layer later. (FIXME: Check this.)
 */
static int being_apply_attribute_modifier(lua_State *s)
{
    Entity *being    = checkBeing(s, 1);
    int attr        = luaL_checkint(s,2);
    double value    = luaL_checknumber(s, 3);
    int layer       = luaL_checkint(s, 4);
    int duration    = luaL_optint(s, 5, 0);
    int effectId    = luaL_optint(s, 6, 0);

    being->getComponent<BeingComponent>()->applyModifier(*being, attr, value,
                                                         layer, duration,
                                                         effectId);
    return 0;
}

/** LUA being_remove_attribute_modifier (being)
 * being_remove_attribute_modifier(handle being, int attribute_id,
 *                                 double value, unsigned int layer)
 **
 * Permits to remove an attribute modifier by giving its value and its layer.
 */
static int being_remove_attribute_modifier(lua_State *s)
{
    Entity *being    = checkBeing(s, 1);
    int attr        = luaL_checkint(s, 2);
    double value    = luaL_checknumber(s, 3);
    int layer       = luaL_checkint(s, 4);
    int effectId    = luaL_optint(s, 5, 0);

    being->getComponent<BeingComponent>()->removeModifier(*being, attr, value,
                                                          layer, effectId);
    return 0;
}

/** LUA being_get_gender (being)
 * being_get_gender(handle being)
 **
 * **Return value:** The gender of the being. These gender constants are
 * defined in libmana-constants.lua:
 *
 * | 0 | GENDER_MALE        |
 * | 1 | GENDER_FEMALE      |
 * | 2 | GENDER_UNSPECIFIED |
 */
static int being_get_gender(lua_State *s)
{
    Entity *b = checkBeing(s, 1);
    lua_pushinteger(s, b->getComponent<BeingComponent>()->getGender());
    return 1;
}

/** LUA being_set_gender (being)
 * being_set_gender(handle being, int gender)
 **
 * Sets the gender of a ''being''.
 *
 * The gender constants are defined in libmana-constants.lua:
 *
 * | 0 | GENDER_MALE        |
 * | 1 | GENDER_FEMALE      |
 * | 2 | GENDER_UNSPECIFIED |
 */
static int being_set_gender(lua_State *s)
{
    Entity *b = checkBeing(s, 1);
    const int gender = luaL_checkinteger(s, 2);
    b->getComponent<BeingComponent>()->setGender(getGender(gender));
    return 0;
}

/** LUA chr_get_level (being)
 * chr_get_level(handle character)
 * chr_get_level(handle character, int skill_id)
 * chr_get_level(handle character, string skill_name)
 **
 * **Return value:** Returns the level of the ''character''. If a skill is
 * passed (either by name or id) the level of this skill is returned.
 *
 * **Note:** If the skill is provided as string (''skill_name'') you have to
 * use this format: <setname>_<skillname>. So for example: "Weapons_Unarmed".
 */
static int chr_get_level(lua_State *s)
{
    Entity *ch = checkCharacter(s, 1);
    auto *characterComponent = ch->getComponent<CharacterComponent>();
    if (lua_gettop(s) > 1)
    {
        int skillId = checkSkill(s, 2);
        lua_pushinteger(s, characterComponent->levelForExp(
                characterComponent->getExperience(skillId)));
    }
    else
    {
        lua_pushinteger(s, characterComponent->getLevel());
    }
    return 1;
}

/** LUA chr_get_exp (being)
 * chr_get_exp(handle character, int skill)
 * chr_get_exp(handle character, int skill)
 **
 * **Return value:** The total experience collected by ''character'' in skill ''skill''.
 *
 * If the skill is provided as string (''skillname'') you have to use this
 * format: <setname>_<skillname>. So for example: "Weapons_Unarmed".
 */
static int chr_get_exp(lua_State *s)
{
    Entity *c = checkCharacter(s, 1);
    int skill = checkSkill(s, 2);
    const int exp = c->getComponent<CharacterComponent>()->getExperience(skill);

    lua_pushinteger(s, exp);
    return 1;
}

/** LUA chr_give_exp (being)
 * chr_give_exp(handle character, int skill, int amount [, int optimalLevel])
 * chr_give_exp(handle character, string skillname, int amount [, int optimalLevel])
 **
 * Gives ''character'' ''amount'' experience in skill ''skill''. When an
 * optimal level is set (over 0), the experience is reduced when the characters
 * skill level is beyond this. If the skill is provided as string
 * (''skillname'') you have to use this format: <setname>_<skillname>.
 * So for example: "Weapons_Unarmed".
 */
static int chr_give_exp(lua_State *s)
{
    Entity *c = checkCharacter(s, 1);
    int skill = checkSkill(s, 2);
    const int exp = luaL_checkint(s, 3);
    const int optimalLevel = luaL_optint(s, 4, 0);

    c->getComponent<CharacterComponent>()->receiveExperience(skill, exp,
                                                             optimalLevel);
    return 0;
}

/** LUA exp_for_level (being)
 * exp_for_level(int level)
 **
 * **Return value:** Returns the total experience necessary (counted from
 * level 0) for reaching ''level'' in any skill.
 */
static int exp_for_level(lua_State *s)
{
    const int level = luaL_checkint(s, 1);
    lua_pushinteger(s, CharacterComponent::expForLevel(level));
    return 1;
}

/** LUA chr_get_hair_color (being)
 * chr_get_hair_color(handle character)
 **
 * **Return value:** The hair color ID of ''character''
 */
static int chr_get_hair_color(lua_State *s)
{
    Entity *c = checkCharacter(s, 1);

    lua_pushinteger(s, c->getComponent<CharacterComponent>()->getHairColor());
    return 1;
}

/** LUA chr_set_hair_color (being)
 * chr_set_hair_color(handle character, int color)
 **
 * Sets the hair color ID of ''character'' to ''color''
 */
static int chr_set_hair_color(lua_State *s)
{
    Entity *c = checkCharacter(s, 1);
    const int color = luaL_checkint(s, 2);
    luaL_argcheck(s, color >= 0, 2, "invalid color id");

    c->getComponent<CharacterComponent>()->setHairColor(color);
    c->getComponent<ActorComponent>()->raiseUpdateFlags(
            UPDATEFLAG_LOOKSCHANGE);

    return 0;
}

/** LUA chr_get_hair_style (being)
 * chr_get_hair_style(handle character)
 **
 * **Return value:** The hair style ID of ''character''
 */
static int chr_get_hair_style(lua_State *s)
{
    Entity *c = checkCharacter(s, 1);

    lua_pushinteger(s, c->getComponent<CharacterComponent>()->getHairStyle());
    return 1;
}

/** LUA chr_set_hair_style (being)
 * chr_set_hair_style(handle character, int style)
 **
 * Sets the hair style ID of ''character'' to ''style''
 */
static int chr_set_hair_style(lua_State *s)
{
    Entity *c = checkCharacter(s, 1);
    const int style = luaL_checkint(s, 2);
    luaL_argcheck(s, style >= 0, 2, "invalid style id");

    c->getComponent<CharacterComponent>()->setHairStyle(style);
    c->getComponent<ActorComponent>()->raiseUpdateFlags(
            UPDATEFLAG_LOOKSCHANGE);
    return 0;
}

/** LUA chr_get_kill_count (being)
 * chr_get_kill_count(handle character, int monsterId)
 * chr_get_kill_count(handle character, string monsterName)
 * chr_get_kill_count(handle character, MonsterClass monsterClass)
 **
 * **Return value:** The total number of monsters of the specy (passed either
 * as monster id, monster name or monster class) the ''character'' has killed
 * during its career.
 */
static int chr_get_kill_count(lua_State *s)
{
    Entity *c = checkCharacter(s, 1);
    MonsterClass *monster = checkMonsterClass(s, 2);

    lua_pushinteger(s, c->getComponent<CharacterComponent>()->getKillCount(monster->getId()));
    return 1;
}

/** LUA chr_get_rights (being)
 * chr_get_rights(handle character)
 **
 * **Return value:** The access level of the account of character.
 */
static int chr_get_rights(lua_State *s)
{
    Entity *c = checkCharacter(s, 1);
    lua_pushinteger(s,
                    c->getComponent<CharacterComponent>()->getAccountLevel());
    return 1;
}

/** LUA chr_kick (being)
 * chr_kick(handle character)
 **
 * Kicks the character.
 */
static int chr_kick(lua_State *s)
{
    Entity *ch = checkCharacter(s, 1);
    MessageOut kickmsg(GPMSG_CONNECT_RESPONSE);
    kickmsg.writeInt8(ERRMSG_ADMINISTRATIVE_LOGOFF);
    ch->getComponent<CharacterComponent>()->getClient()->disconnect(kickmsg);
    return 0;
}

/** LUA being_get_mapid (being)
 * being_get_mapid(handle Being)
 **
 * **Return value:** the id of the map where the being is located
 * or nil if there is none.
 */
static int being_get_mapid(lua_State *s)
{
    Entity *being = checkBeing(s, 1);
    if (MapComposite *map = being->getMap())
        lua_pushinteger(s, map->getID());
    else
        lua_pushnil(s);

    return 1;
}

/** LUA chr_request_quest (being)
 * chr_request_quest(handle character, string questvariable, Ref function)
 **
 * Requests the questvar from the account server. This will make it available in
 * the quest cache after some time. The passed function will be called back as
 * soon the quest var is available.
 */
static int chr_request_quest(lua_State *s)
{
    Entity *ch = checkCharacter(s, 1);
    const char *name = luaL_checkstring(s, 2);
    luaL_argcheck(s, name[0] != 0, 2, "empty variable name");
    luaL_checktype(s, 3, LUA_TFUNCTION);

    std::string value;
    bool res = getQuestVar(ch, name, value);
    if (res)
    {
        // Already cached, call passed callback immediately
        Script *script = getScript(s);
        Script::Ref callback;
        script->assignCallback(callback);

        script->prepare(callback);
        script->push(ch);
        script->push(name);
        script->push(value);
        script->execute(ch->getMap());

        return 0;
    }

    QuestCallback *f = new QuestRefCallback(getScript(s), name);
    recoverQuestVar(ch, name, f);

    return 0;
}

/** LUA chr_try_get_quest (being)
 * chr_try_get_quest(handle character, string questvariable)
 **
 * Callback for checking if a quest variable is available in cache.
 *
 * **Return value:** It will return the variable if it is or nil
 * if it is not in cache.
 */
static int chr_try_get_quest(lua_State *s)
{
    Entity *q = checkCharacter(s, 1);
    const char *name = luaL_checkstring(s, 2);
    luaL_argcheck(s, name[0] != 0, 2, "empty variable name");

    std::string value;
    bool res = getQuestVar(q, name, value);
    if (res)
        push(s, value);
    else
        lua_pushnil(s);
    return 1;
}

/** LUA get_character_by_name (being)
 * get_character_by_name(string name)
 **
 * Tries to find an online character by name.
 *
 * **Return value** the character handle or nil if there is none
 */
static int get_character_by_name(lua_State *s)
{
    const char *name = luaL_checkstring(s, 1);

    Entity *ch = gameHandler->getCharacterByNameSlow(name);
    if (!ch)
        lua_pushnil(s);
    else
        lua_pushlightuserdata(s, ch);

    return 1;
}

/** LUA chr_get_post (being)
 * chr_get_post(handle character)
 **
 * Gets the post for the character.
 */
static int chr_get_post(lua_State *s)
{
    Entity *c = checkCharacter(s, 1);

    Script *script = getScript(s);
    Script::Thread *thread = checkCurrentThread(s, script);

    PostCallback f = { &LuaScript::getPostCallback, script };
    postMan->getPost(c, f);

    thread->mState = Script::ThreadExpectingTwoStrings;
    return lua_yield(s, 0);
}

/** LUA being_register (being)
 * being_register(handle being)
 **
 * Makes the server call the on_being_death and on_being_remove callbacks
 * when the being dies or is removed from the map.
 *
 * **Note:** You should never need to call this in most situations. It is
 * handeled by the libmana.lua
 */
static int being_register(lua_State *s)
{
    Entity *being = checkBeing(s, 1);
    Script *script = getScript(s);

    being->getComponent<BeingComponent>()->signal_died.connect(
            sigc::mem_fun(script, &Script::processDeathEvent));
    being->signal_removed.connect(sigc::mem_fun(script, &Script::processRemoveEvent));

    return 0;
}

/** LUA chr_shake_screen (being)
 * chr_shake_screen(handle character, int x, int y[, float strength, int radius])
 **
 * Shake the screen for a given character.
 */
static int chr_shake_screen(lua_State *s)
{
    Entity *c = checkCharacter(s, 1);
    const int x = luaL_checkint(s, 2);
    const int y = luaL_checkint(s, 3);

    MessageOut msg(GPMSG_SHAKE);
    msg.writeInt16(x);
    msg.writeInt16(y);

    if (lua_isnumber(s, 4))
        msg.writeInt16((int) (lua_tonumber(s, 4) * 10000));
    if (lua_isnumber(s, 5))
        msg.writeInt16(lua_tointeger(s, 5));

    c->getComponent<CharacterComponent>()->getClient()->send(msg);

    return 0;
}

/** LUA chr_create_text_particle (being)
 * chr_create_text_particle(handle character, string text)
 **
 * Creates a text particle on a client. This effect is only visible for the
 * ''character''.
 */
static int chr_create_text_particle(lua_State *s)
{
    Entity *c = checkCharacter(s, 1);
    const char *text = luaL_checkstring(s, 2);

    MessageOut msg(GPMSG_CREATE_TEXT_PARTICLE);
    msg.writeString(text);
    c->getComponent<CharacterComponent>()->getClient()->send(msg);

    return 0;
}

/** LUA chr_give_special (being)
 * chr_give_special(handle character, int special)
 **
 * Enables a special for a character.
 */
static int chr_give_special(lua_State *s)
{
    // cost_type is ignored until we have more than one cost type
    Entity *c = checkCharacter(s, 1);
    const int special = checkSpecial(s, 2);
    const int currentMana = luaL_optint(s, 3, 0);

    c->getComponent<CharacterComponent>()->giveSpecial(special, currentMana);
    return 0;
}

/** LUA chr_has_special (being)
 * chr_has_special(handle character, int special)
 **
 * **Return value:** True if the ''character'' has the special. False otherwise
 */
static int chr_has_special(lua_State *s)
{
    Entity *c = checkCharacter(s, 1);
    const int special = luaL_checkint(s, 2);

    lua_pushboolean(s, c->getComponent<CharacterComponent>()->hasSpecial(
            special));
    return 1;
}

/** LUA chr_take_special (being)
 * chr_take_special(handle character, int special)
 **
 * Removes a special from a character.
 *
 * **Return value:** True if removal was successful. False otherwise
 * (in case the ''character'' did not have the special)
 */
static int chr_take_special(lua_State *s)
{
    Entity *c = checkCharacter(s, 1);
    const int special = luaL_checkint(s, 2);

    lua_pushboolean(s, c->getComponent<CharacterComponent>()->hasSpecial(
            special));
    c->getComponent<CharacterComponent>()->takeSpecial(special);
    return 1;
}


/** LUA_CATEGORY Monster (monster)
 */

/** LUA monster_get_id (monster)
 * monster_get_id(handle monster)
 **
 * **Return value:** The id of the specy of the monster handle.
 */
static int monster_get_id(lua_State *s)
{
    Entity *monster = checkMonster(s, 1);
    MonsterComponent *monsterComponent =
            monster->getComponent<MonsterComponent>();
    lua_pushinteger(s, monsterComponent->getSpecy()->getId());
    return 1;
}

/** LUA monster_change_anger (monster)
 * monster_change_anger(handle monster, handle being, int anger)
 **
 * Makes the ''monster'' more angry about the ''being'' by adding ''anger'' to
 * the being.
 */
static int monster_change_anger(lua_State *s)
{
    Entity *monster = checkMonster(s, 1);
    Entity *being = checkBeing(s, 2);
    const int anger = luaL_checkint(s, 3);
    monster->getComponent<MonsterComponent>()->changeAnger(being, anger);
    return 0;
}

/** LUA monster_drop_anger (monster)
 * monster_drop_anger(handle monster, handle target)
 **
 * Will drop all anger against the ''target''.
 */
static int monster_drop_anger(lua_State *s)
{
    Entity *monster = checkMonster(s, 1);
    Entity *being = checkBeing(s, 2);
    monster->getComponent<MonsterComponent>()->forgetTarget(being);
    return 0;
}

/** LUA monster_get_angerlist (monster)
 * monster_get_angerlist(handle monster)
 **
 * **Return value:** A table with the beings as key and the anger against them
 * as values.
 */
static int monster_get_angerlist(lua_State *s)
{
    Entity *monster = checkMonster(s, 1);
    MonsterComponent *monsterComponent =
            monster->getComponent<MonsterComponent>();
    pushSTLContainer(s, monsterComponent->getAngerList());
    return 1;
}


/** LUA_CATEGORY Status effects (statuseffects)
 */

/** LUA being_apply_status (statuseffects)
 * being_apply_status(handle Being, int status_id, int time)
 **
 * Gives a ''being'' a status effect ''status_id'', status effects don't work
 * on NPCs. ''time'' is in game ticks.
 */
static int being_apply_status(lua_State *s)
{
    Entity *being = checkBeing(s, 1);
    const int id = luaL_checkint(s, 2);
    const int time = luaL_checkint(s, 3);

    being->getComponent<BeingComponent>()->applyStatusEffect(id, time);
    return 0;
}

/** LUA being_remove_status (statuseffects)
 * being_remove_status(handle Being, int status_id)
 **
 * Removes a given status effect from a being.
 */
static int being_remove_status(lua_State *s)
{
    Entity *being = checkBeing(s, 1);
    const int id = luaL_checkint(s, 2);

    being->getComponent<BeingComponent>()->removeStatusEffect(id);
    return 0;
}

/** LUA being_has_status (statuseffects)
 * being_has_status(handle Being, int status_id)
 **
 * **Return value:** Bool if the being has a given status effect.
 */
static int being_has_status(lua_State *s)
{
    Entity *being = checkBeing(s, 1);
    const int id = luaL_checkint(s, 2);

    lua_pushboolean(s, being->getComponent<BeingComponent>()
                    ->hasStatusEffect(id));
    return 1;
}

/** LUA being_get_status_time (statuseffects)
 * being_get_status_time(handle Being, int status_id)
 **
 * **Return Value:** Number of ticks remaining on a status effect.
 */
static int being_get_status_time(lua_State *s)
{
    Entity *being = checkBeing(s, 1);
    const int id = luaL_checkint(s, 2);

    lua_pushinteger(s, being->getComponent<BeingComponent>()
                    ->getStatusEffectTime(id));
    return 1;
}

/** LUA being_set_status_time (statuseffects)
 * being_set_status_time(handle Being, int status_id, int time)
 **
 * Sets the time on a status effect a target being already has.
 */
static int being_set_status_time(lua_State *s)
{
    Entity *being = checkBeing(s, 1);
    const int id = luaL_checkint(s, 2);
    const int time = luaL_checkint(s, 3);

    being->getComponent<BeingComponent>()->setStatusEffectTime(id, time);
    return 0;
}


/** LUA_CATEGORY Map information (mapinformation)
 */

/** LUA get_map_id (mapinformation)
 * get_map_id()
 **
 * **Return value:** The ID number of the map the script runs on.
 */
static int get_map_id(lua_State *s)
{
    Script *script = getScript(s);

    if (MapComposite *mapComposite = script->getContext()->map)
        lua_pushinteger(s, mapComposite->getID());
    else
        lua_pushnil(s);

    return 1;
}

/** LUA get_map_property (mapinformation)
 * get_map_property(string key)
 **
 * **Return value:** The value of the property ''key'' of the current map. The
 * string is empty if the property ''key'' does not exist.
 */
static int get_map_property(lua_State *s)
{
    const char *property = luaL_checkstring(s, 1);
    Map *map = checkCurrentMap(s)->getMap();

    push(s, map->getProperty(property));
    return 1;
}

/** LUA is_walkable (mapinformation)
 * is_walkable(int x, int y)
 **
 * **Return value:** True if ''x'':''y'' is a walkable pixel
 * on the current map.
 */
static int is_walkable(lua_State *s)
{
    const int x = luaL_checkint(s, 1);
    const int y = luaL_checkint(s, 2);
    Map *map = checkCurrentMap(s)->getMap();

    // If the wanted warp place is unwalkable
    if (map->getWalk(x / map->getTileWidth(), y / map->getTileHeight()))
        lua_pushboolean(s, 1);
    else
        lua_pushboolean(s, 0);

    return 1;
}

/** LUA map_get_pvp (mapinformation)
 * map_get_pvp()
 **
 * **Return value:** The pvp situation of the map.
 *
 * There are constants for the different pvp situations in the libmana-constants.lua:
 *
 * | 0 | PVP_NONE  |
 * | 1 | PVP_FREE  |
 */
static int map_get_pvp(lua_State *s)
{
    MapComposite *m = checkCurrentMap(s);
    lua_pushinteger(s, m->getPvP());
    return 1;
}


/** LUA_CATEGORY General Information (information)
 */

/** LUA monster_get_name (information)
 * get_map_id()
 **
 * **Return value:** The ID number of the map the script runs on.
 */
static int monster_get_name(lua_State *s)
{
    const int id = luaL_checkint(s, 1);
    MonsterClass *spec = monsterManager->getMonster(id);
    if (!spec)
    {
        luaL_error(s, "monster_get_name called with unknown monster id.");
        return 0;
    }
    push(s, spec->getName());
    return 1;
}

/** LUA item_get_name (information)
 * get_map_property(string key)
 **
 * **Return value:** The value of the property ''key'' of the current map.
 * The string is empty if the property ''key'' does not exist.
 */
static int item_get_name(lua_State *s)
{
    const int id = luaL_checkint(s, 1);
    ItemClass *it = itemManager->getItem(id);
    if (!it)
    {
        luaL_error(s, "item_get_name called with unknown item id.");
        return 0;
    }
    push(s, it->getName());
    return 1;
}

/** LUA_CATEGORY Persistent variables (variables)
 */

/** LUA on_mapvar_changed (variables)
 * on_mapvar_changed(string key, function func)
 **
 * Registers a callback to the key. This callback will be called with the key
 * and value of the changed variable.
 *
 * **Example:**
 * <code lua>on_mapvar_changed(key, function(key, value)
 *   log(LOG_DEBUG, "mapvar " .. key .. " has new value " .. value)
 * end)</code>
 */
static int on_mapvar_changed(lua_State *s)
{
    const char *key = luaL_checkstring(s, 1);
    luaL_checktype(s, 2, LUA_TFUNCTION);
    luaL_argcheck(s, key[0] != 0, 2, "empty variable name");
    MapComposite *m = checkCurrentMap(s);
    m->setMapVariableCallback(key, getScript(s));
    return 0;
}

/** LUA on_worldvar_changed (variables)
 * on_worldvar_changed(string key, function func)
 **
 * Registers a callback to the key. This callback will be called with the key
 * and value of the changed variable.
 *
 * **Example:**
 * <code lua>on_worldvar_changed(key, function(key, value)
 *   log(LOG_DEBUG, "worldvar " .. key .. " has new value " .. value)
 * end)</code>
 */
static int on_worldvar_changed(lua_State *s)
{
    const char *key = luaL_checkstring(s, 1);
    luaL_checktype(s, 2, LUA_TFUNCTION);
    luaL_argcheck(s, key[0] != 0, 2, "empty variable name");
    MapComposite *m = checkCurrentMap(s);
    m->setWorldVariableCallback(key, getScript(s));
    return 0;
}

/** LUA getvar_map (variables)
 * getvar_map(string variablename)
 **
 * **Return value:** the value of a persistent map variable.
 *
 * **See:** [[scripting#map|map[]]] for an easier way to get a map variable.
 */
static int getvar_map(lua_State *s)
{
    const char *name = luaL_checkstring(s, 1);
    luaL_argcheck(s, name[0] != 0, 1, "empty variable name");

    MapComposite *map = checkCurrentMap(s);

    push(s, map->getVariable(name));
    return 1;
}

/** LUA setvar_map (variables)
 * setvar_map(string variablename, string value)
 **
 * Sets the value of a persistent map variable.
 *
 * **See:** [[scripting#map|map[]]] for an easier way to get a map variable.
 */
static int setvar_map(lua_State *s)
{
    const char *name = luaL_checkstring(s, 1);
    const char *value = luaL_checkstring(s, 2);
    luaL_argcheck(s, name[0] != 0, 1, "empty variable name");

    MapComposite *map = checkCurrentMap(s);
    map->setVariable(name, value);

    return 0;
}

/** LUA getvar_world (variables)
 * getvar_world(string variablename)
 **
 * Gets the value of a persistent global variable.
 *
 * **See:** [[scripting#world|world[]]] for an easier way to get a map variable.
 */
static int getvar_world(lua_State *s)
{
    const char *name = luaL_checkstring(s, 1);
    luaL_argcheck(s, name[0] != 0, 1, "empty variable name");

    push(s, GameState::getVariable(name));
    return 1;
}

/** LUA setvar_world (variables)
 * setvar_world(string variablename, string value)
 **
 * Sets the value of a persistent global variable.
 *
 * **See:** [[scripting#world|world[]]] for an easier way to get a map variable.
 */
static int setvar_world(lua_State *s)
{
    const char *name = luaL_checkstring(s, 1);
    const char *value = luaL_checkstring(s, 2);
    luaL_argcheck(s, name[0] != 0, 1, "empty variable name");

    GameState::setVariable(name, value);
    return 0;
}


/** LUA_CATEGORY Logging (logging)
 */

/** LUA log (logging)
 * log(int log_level, string message)
 **
 * Log something at the specified log level. The available log levels are:
 * | 0 | LOG_FATAL    |
 * | 1 | LOG_ERROR    |
 * | 2 | LOG_WARNING  |
 * | 3 | LOG_INFO     |
 * | 4 | LOG_DEBUG    |
 */
static int log(lua_State *s)
{
    using utils::Logger;

    const int loglevel = luaL_checkint(s, 1);
    luaL_argcheck(s,
                  loglevel >= Logger::Fatal && loglevel <= Logger::Debug,
                  1,
                  "invalid log level");

    const std::string message = luaL_checkstring(s, 2);

    Logger::output(message, (Logger::Level) loglevel);
    return 0;
}


/** LUA_CATEGORY Area of Effect (area)
 * In order to easily use area of effects in your items or in your scripts,
 * the following functions are available:
 */

/** LUA get_beings_in_circle (area)
 * get_beings_in_circle(int x, int y, int radius)
 * get_beings_in_circle(handle being, int radius)
 **
 * **Return value:** This function returns a lua table of all beings in a
 * circle of radius (in pixels) ''radius'' centered either at the pixel at
 * (''x'', ''y'') or at the position of ''being''.
 */
static int get_beings_in_circle(lua_State *s)
{
    int x, y, r;
    if (lua_islightuserdata(s, 1))
    {
        Entity *b = checkBeing(s, 1);
        const Point &pos = b->getComponent<ActorComponent>()->getPosition();
        x = pos.x;
        y = pos.y;
        r = luaL_checkint(s, 2);
    }
    else
    {
        x = luaL_checkint(s, 1);
        y = luaL_checkint(s, 2);
        r = luaL_checkint(s, 3);
    }

    MapComposite *m = checkCurrentMap(s);

    //create a lua table with the beings in the given area.
    lua_newtable(s);
    int tableStackPosition = lua_gettop(s);
    int tableIndex = 1;
    for (BeingIterator i(m->getAroundPointIterator(Point(x, y), r)); i; ++i)
    {
        Entity *b = *i;
        char t = b->getType();
        if (t == OBJECT_NPC || t == OBJECT_CHARACTER || t == OBJECT_MONSTER)
        {
            auto *actorComponent = b->getComponent<ActorComponent>();
            if (Collision::circleWithCircle(actorComponent->getPosition(),
                                            actorComponent->getSize(),
                                            Point(x, y), r))
            {
                lua_pushlightuserdata(s, b);
                lua_rawseti(s, tableStackPosition, tableIndex);
                tableIndex++;
            }
        }
    }

    return 1;
}

/** LUA get_beings_in_rectangle (area)
 * get_beings_in_rectangle(int x, int y, int width, int height)
 **
 * **Return value:** An table of being objects within the rectangle.
 * All parameters have to be passed as pixels.
 */
static int get_beings_in_rectangle(lua_State *s)
{
    const int x = luaL_checkint(s, 1);
    const int y = luaL_checkint(s, 2);
    const int w = luaL_checkint(s, 3);
    const int h = luaL_checkint(s, 4);

    MapComposite *m = checkCurrentMap(s);

    //create a lua table with the beings in the given area.
    lua_newtable(s);
    int tableStackPosition = lua_gettop(s);
    int tableIndex = 1;
    Rectangle rect = {x, y ,w, h};
    for (BeingIterator i(m->getInsideRectangleIterator(rect)); i; ++i)
    {
        Entity *b = *i;
        char t = b->getType();
        if ((t == OBJECT_NPC || t == OBJECT_CHARACTER || t == OBJECT_MONSTER) &&
            rect.contains(b->getComponent<ActorComponent>()->getPosition()))
        {
            lua_pushlightuserdata(s, b);
            lua_rawseti(s, tableStackPosition, tableIndex);
            tableIndex++;
        }
    }
     return 1;
 }

/** LUA get_distance (area)
 * get_distance(handle being1, handle being2)
 * get_distance(int x1, int y1, int x2, int y2)
 **
 * **Return value:** The distance between the two beings or the two points
 * in pixels.
 */
static int get_distance(lua_State *s)
{
    int x1, y1, x2, y2;
    if (lua_gettop(s) == 2)
    {
        Entity *being1 = checkBeing(s, 1);
        Entity *being2 = checkBeing(s, 2);

        x1 = being1->getComponent<ActorComponent>()->getPosition().x;
        y1 = being1->getComponent<ActorComponent>()->getPosition().y;
        x2 = being2->getComponent<ActorComponent>()->getPosition().x;
        y2 = being2->getComponent<ActorComponent>()->getPosition().y;
    }
    else
    {
        x1 = luaL_checkint(s, 1);
        y1 = luaL_checkint(s, 2);
        x2 = luaL_checkint(s, 3);
        y2 = luaL_checkint(s, 4);
    }
    const int dx = x1 - x2;
    const int dy = y1 - y2;
    const float dist = sqrt((dx * dx) + (dy * dy));
    lua_pushinteger(s, dist);

    return 1;
}


/** LUA_CATEGORY Special info class (specialinfo)
 * See the [[specials.xml#A script example|specials Documentation]] for a
 * script example
 */

/** LUA get_special_info (specialinfo)
 * get_special_info(int specialId)
 * get_special_info(string specialName)
 **
 * **Return value:** This function returns a object of the specialinfo class.
 * See below for usage of that object.
 *
 * **Note:** When passing the ''specialName'' as parameter make sure that it is
 * formatted in this way: <setname>_<specialname> (for eg. "Magic_Healingspell").
 */
static int get_special_info(lua_State *s)
{
    const int special = checkSpecial(s, 1);
    SpecialManager::SpecialInfo *info = specialManager->getSpecialInfo(special);
    luaL_argcheck(s, info, 1, "invalid special");
    LuaSpecialInfo::push(s, info);
    return 1;
}

/** LUA specialinfo:name (specialinfo)
 * specialinfo:name()
 **
 * ** Return value:** The name of the specialinfo object.
 *
 * **Note:** See [[scripting#get_special_info|get_special_info]] for getting a
 * specialinfo object.
 */
static int specialinfo_get_name(lua_State *s)
{
    SpecialManager::SpecialInfo *info = LuaSpecialInfo::check(s, 1);
    push(s, info->name);
    return 1;
}

/** LUA specialinfo:needed_mana (specialinfo)
 * specialinfo:needed_mana()
 **
 * ** Return value:** The mana that is needed to use the special
 *
 * **Note:** See [[scripting#get_special_info|get_special_info]] for getting a
 * specialinfo object.
 */
static int specialinfo_get_needed_mana(lua_State *s)
{
    SpecialManager::SpecialInfo *info = LuaSpecialInfo::check(s, 1);
    lua_pushinteger(s, info->neededMana);
    return 1;
}

/** LUA specialinfo:rechargeable (specialinfo)
 * specialinfo:rechargeable()
 **
 * ** Return value:** A boolean value that indicates whether the special is
 * rechargeable or usuable without recharge.
 *
 * **Note:** See [[scripting#get_special_info|get_special_info]] for getting
 * a specialinfo object.
 */
static int specialinfo_is_rechargeable(lua_State *s)
{
    SpecialManager::SpecialInfo *info = LuaSpecialInfo::check(s, 1);
    lua_pushboolean(s, info->rechargeable);
    return 1;
}

/** LUA specialinfo:on_use (specialinfo)
 * specialinfo:on_use(function callback)
 **
 * Assigns the ''callback'' as callback for the use event. This function will
 * be called everytime a character uses a special.
 *
 * **Note:** See [[scripting#get_special_info|get_special_info]] for getting
 * a specialinfo object.
 */
static int specialinfo_on_use(lua_State *s)
{
    SpecialManager::SpecialInfo *info = LuaSpecialInfo::check(s, 1);
    Script *script = getScript(s);
    luaL_checktype(s, 2, LUA_TFUNCTION);
    script->assignCallback(info->useCallback);
    return 0;
}

/** LUA specialinfo:on_recharged (specialinfo)
 * specialinfo:on_recharged(function callback)
 **
 * Assigns the ''callback'' as callback for the recharged event. This function
 * will be called everytime when the special is fully recharged.
 *
 * **Note:** See [[scripting#get_special_info|get_special_info]] for getting
 * a specialinfo object.
 */
static int specialinfo_on_recharged(lua_State *s)
{
    SpecialManager::SpecialInfo *info = LuaSpecialInfo::check(s, 1);
    Script *script = getScript(s);
    luaL_checktype(s, 2, LUA_TFUNCTION);
    script->assignCallback(info->rechargedCallback);
    return 0;
}

/** LUA specialinfo:category (specialinfo)
 * specialinfo:category(function callback)
 **
 * **Return value:** The set-name of the special as defined in the
 * [[specials.xml]]
 *
 * **Note:** See [[scripting#get_special_info|get_special_info]] for getting
 * a specialinfo object.
 */
static int specialinfo_get_category(lua_State *s)
{
    SpecialManager::SpecialInfo *info = LuaSpecialInfo::check(s, 1);
    push(s, info->setName);
    return 1;
}


/** LUA_CATEGORY Status effect class (statuseffectclass)
 */

/** LUA get_status_effect (statuseffectclass)
 * get_status_effect(string name)
 **
 * **Return value:** This function returns a object of the statuseffect class.
 * See below for usage of that object.
 */
static int get_status_effect(lua_State *s)
{
    const char *name = luaL_checkstring(s, 1);
    LuaStatusEffect::push(s, StatusManager::getStatusByName(name));
    return 1;
}

/** LUA statuseffect:on_tick (statuseffectclass)
 * statuseffect:on_tick(function callback)
 **
 * Sets the callback that gets called for every tick when the status effect
 * is active.
 *
 * **Note:** See [[scripting#get_status_effect|get_status_effect]] for getting
 * a statuseffect object.
 */
static int status_effect_on_tick(lua_State *s)
{
    StatusEffect *statusEffect = LuaStatusEffect::check(s, 1);
    luaL_checktype(s, 2, LUA_TFUNCTION);
    statusEffect->setTickCallback(getScript(s));
    return 0;
}

/** LUA_CATEGORY Monster class (monsterclass)
 */

/** LUA get_monster_class (monsterclass)
 * get_monster_class(int monsterid)
 * get_monster_class(string monstername)
 **
 * **Return value:** This function returns a object of the monster class.
 * See below for usage of that object.
 */
static int get_monster_class(lua_State *s)
{
    LuaMonsterClass::push(s, checkMonsterClass(s, 1));
    return 1;
}

/** LUA monsterclass:on_update (monsterclass)
 * monsterclass:on_update(function callback)
 **
 * Assigns the ''callback'' as callback for the monster update event. This
 * callback will be called every tick for each monster of that class.
 *
 * **Note:** See [[scripting#get_monster_class|get_monster_class]] for getting
 * a monsterclass object.
 */
static int monster_class_on_update(lua_State *s)
{
    MonsterClass *monsterClass = LuaMonsterClass::check(s, 1);
    luaL_checktype(s, 2, LUA_TFUNCTION);
    monsterClass->setUpdateCallback(getScript(s));
    return 0;
}

/** LUA monsterclass:on_damage (monsterclass)
 * monsterclass:on_damage(function callback)
 **
 * Assigns the ''callback'' as callback for the monster damage event.
 * This callback will be called every time when a monster takes damage.
 * The damage can be either invoked from scripts or from other beings such
 * as players. The parameters of the callback are: the attacked monster,
 * the being dealing the damage and the hp loss
 *
 * **Note:** See [[scripting#get_monster_class|get_monster_class]] for getting
 * a monsterclass object.
 *
 * **Example:** <code lua>
 * local function damage(mob, aggressor, hploss)
 *     being_say(mob, "I took damage -.- ".. hploss)
 *     if aggressor then
 *         being_say(mob, "Curse you, ".. being_get_name(aggressor))
 *     end
 * end
 * local maggot = get_monster_class("maggot")
 * maggot:on_damage(damage)</code>
 */
static int monster_class_on_damage(lua_State *s)
{
    MonsterClass *monsterClass = LuaMonsterClass::check(s, 1);
    luaL_checktype(s, 2, LUA_TFUNCTION);
    monsterClass->setDamageCallback(getScript(s));
    return 0;
}

/** LUA monsterclass:attacks (monsterclass)
 * monsterclass:attacks()
 **
 * **Return value:** This function returns a table with all attacks of the
 * monster. See the [[scripting#AttackInfo class|Attack Info]] section.
 */
static int monster_class_attacks(lua_State *s)
{
    MonsterClass *monsterClass = LuaMonsterClass::check(s, 1);
    pushSTLContainer(s, monsterClass->getAttackInfos());
    return 1;
}


/** LUA_CATEGORY AttackInfo class (attackinfoclass)
 * The AttackInfo class reveals info about attacks and provides functions to
 * register callbacks on attacks. See the
 * [[attackconfiguration|Attack Configuration]] for more info.
 * To get an AttackInfo use
 * [[scripting#monsterclass:attacks|monsterclass:attacks]] or
 * [[scripting#itemclass:attacks|itemclass:attacks]]
 */

/** LUA attackinfo:priority (attackinfoclass)
 * attackinfo:priority()
 **
 * **Return value:** This function returns the priority of the attack.
 */
static int attack_get_priority(lua_State *s)
{
    AttackInfo *attack = LuaAttackInfo::check(s, 1);
    lua_pushinteger(s, attack->getPriority());
    return 1;
}

/** LUA attackinfo:cooldowntime (attackinfoclass)
 * attackinfo:cooldowntime()
 **
 * **Return value:** This function returns the cooldowntime (time after dealing
 * damage after which a new attack can be used) of the attack.
 */
static int attack_get_cooldowntime(lua_State *s)
{
    AttackInfo *attack = LuaAttackInfo::check(s, 1);
    lua_pushinteger(s, attack->getCooldownTime());
    return 1;
}

/** LUA attackinfo:warmuptime (attackinfoclass)
 * attackinfo:warmuptime()
 **
 * **Return value:** This function returns the warmuptime (time before a attack
 * triggers damage after being used) of the attack.
 */
static int attack_get_warmuptime(lua_State *s)
{
    AttackInfo *attack = LuaAttackInfo::check(s, 1);
    lua_pushinteger(s, attack->getWarmupTime());
    return 1;
}

/** LUA attackinfo:reusetime (attackinfoclass)
 * attackinfo:reusetime()
 **
 * **Return value:** This function returns the reusetime (time after which the
 * same attack can be used again) of the attack.
 */
static int attack_get_reusetime(lua_State *s)
{
    AttackInfo *attack = LuaAttackInfo::check(s, 1);
    lua_pushinteger(s, attack->getReuseTime());
    return 1;
}

/** LUA attackinfo:damage (attackinfoclass)
 * >attackinfo:damage()
 **
 * **Return value:** This function returns the damage info of the attack.
 *
 * **See also:** [[scripting#Damage Class|Damage Class]]
 */
static int attack_get_damage(lua_State *s)
{
    AttackInfo *attack = LuaAttackInfo::check(s, 1);
    LuaDamage::push(s, &attack->getDamage());
    return 1;
}

/** LUA attackinfo:on_attack (attackinfoclass)
 * attackinfo:on_attack(function callback)
 **
 * Assigns a callback to the attack that will be called as soon the attack is
 * used. The callback will get called with the following parameters:
 * being user, being target, int damage_dealt.
 */
static int attack_on_attack(lua_State *s)
{
    AttackInfo *attack = LuaAttackInfo::check(s, 1);
    luaL_checktype(s, 2, LUA_TFUNCTION);
    attack->setCallback(getScript(s));
    return 0;
}


/** LUA_CATEGORY Damage Class (damageclass)
 * The Damage class provides info about the kind of damage attack deals.
 */

/** LUA damage:id (damageclass)
 * damage:id()
 **
 * **Return value:** This function returns the id of the attack.
 */
static int damage_get_id(lua_State *s)
{
    Damage *damage = LuaDamage::check(s, 1);
    lua_pushinteger(s, damage->id);
    return 1;
}

/** LUA damage:skill (damageclass)
 * damage:skill()
 **
 * **Return value:** This function returns the skill id of the attack. If the
 * damage dealer is a character is a character this skill will recieve exp.
 */
static int damage_get_skill(lua_State *s)
{
    Damage *damage = LuaDamage::check(s, 1);
    lua_pushinteger(s, damage->skill);
    return 1;
}

/** LUA damage:base (damageclass)
 * damage:base()
 **
 * **Return value:** This function returns the base damage of the attack.
 * It is the minimum of damage dealt.
 */
static int damage_get_base(lua_State *s)
{
    Damage *damage = LuaDamage::check(s, 1);
    lua_pushinteger(s, damage->base);
    return 1;
}

/** LUA damage:delta (damageclass)
 * damage:delta()
 **
 * **Return value:** This function returns the damage delta of the attack.
 * base damage + delta damage is the maximum of damage the attack can cause.
 * A number in between will be picked by random.
 */
static int damage_get_delta(lua_State *s)
{
    Damage *damage = LuaDamage::check(s, 1);
    lua_pushinteger(s, damage->delta);
    return 1;
}

/** LUA damage:cth (damageclass)
 * damage:cth()
 **
 * **Return value:** This function returns the chance to hit of the attack.
 * This number is not a percent value but some factor. Higher means a better
 * chance to hit. FIXME: Add info about the factor.
 */
static int damage_get_cth(lua_State *s)
{
    Damage *damage = LuaDamage::check(s, 1);
    lua_pushinteger(s, damage->cth);
    return 1;
}

/** LUA damage:element (damageclass)
 * damage:element()
 **
 * **Return value:** This function returns the element of the attack.
 *
 * **See:** [[scripting#being_damage|being_damage]] for possible values.
 */
static int damage_get_element(lua_State *s)
{
    Damage *damage = LuaDamage::check(s, 1);
    lua_pushinteger(s, damage->element);
    return 1;
}

/** LUA damage:type (damageclass)
 * damage:type()
 **
 * **Return value:** This function returns the type of the attack.
 *
 * **See:** [[scripting#being_damage|being_damage]] for possible values.
 */
static int damage_get_type(lua_State *s)
{
    Damage *damage = LuaDamage::check(s, 1);
    lua_pushinteger(s, damage->type);
    return 1;
}

/** LUA damage:is_truestrike (damageclass)
 * damage:is_truestrike()
 **
 * **Return value:** This function returns whether the attack is a true strike.
 * A true strike is not effected by chance of hit or anything that could
 * prevent the hit.
 */
static int damage_is_truestrike(lua_State *s)
{
    Damage *damage = LuaDamage::check(s, 1);
    lua_pushboolean(s, damage->trueStrike);
    return 1;
}

/** LUA damage:range (damageclass)
 * damage:range()
 **
 * **Return value:** This function returns the range of the attack in pixels.
 */
static int damage_get_range(lua_State *s)
{
    Damage *damage = LuaDamage::check(s, 1);
    lua_pushinteger(s, damage->range);
    return 1;
}


/** LUA_CATEGORY Map object class (mapobjectclass)
 */

/** LUA map_get_objects (mapobjectclass)
 * map_get_objects()
 * map_get_objects(string type)
 **
 * **Return value:** A table of all objects or a table of all objects of the
 * given ''type''. See below for usage of these objects.
 */
static int map_get_objects(lua_State *s)
{
    const bool filtered = (lua_gettop(s) == 1);
    const char *filter;
    if (filtered)
    {
        filter = luaL_checkstring(s, 1);
    }

    MapComposite *m = checkCurrentMap(s);
    const std::vector<MapObject*> &objects = m->getMap()->getObjects();

    if (!filtered)
        pushSTLContainer<MapObject*>(s, objects);
    else
    {
        std::vector<MapObject*> filteredObjects;
        for (std::vector<MapObject*>::const_iterator it = objects.begin();
             it != objects.end(); ++it)
        {
            if (utils::compareStrI((*it)->getType(), filter) == 0)
            {
                filteredObjects.push_back(*it);
            }
        }
        pushSTLContainer<MapObject*>(s, filteredObjects);
    }
    return 1;
}

/** LUA mapobject:property (mapobjectclass)
 * mapobject:property(string key)
 **
 * **Return value:** The value of the property of the key ''key'' or nil if
 * the property does not exists.
 *
 * **Note:** See [[scripting#map_get_objects|map_get_objects]] for getting a
 * monsterclass object.
 */
static int map_object_get_property(lua_State *s)
{
    const char *key = luaL_checkstring(s, 2);
    MapObject *obj = LuaMapObject::check(s, 1);

    std::string property = obj->getProperty(key);
    if (!property.empty())
    {
        push(s, property);
        return 1;
    }
    else
    {
        // scripts can check for nil
        return 0;
    }
}

/** LUA mapobject:bounds (mapobjectclass)
 * mapobject:bounds()
 **
 * **Return value:** x, y position and height, width of the ''mapobject''.
 *
 * **Example use:**
 * <code lua>local x, y, width, height = my_mapobject:bounds()</code>
 *
 * **Note:** See [[scripting#map_get_objects|map_get_objects]] for getting a
 * mapobject object.
 */
static int map_object_get_bounds(lua_State *s)
{
    MapObject *obj = LuaMapObject::check(s, 1);
    const Rectangle &bounds = obj->getBounds();
    lua_pushinteger(s, bounds.x);
    lua_pushinteger(s, bounds.y);
    lua_pushinteger(s, bounds.w);
    lua_pushinteger(s, bounds.h);
    return 4;
}

/** LUA mapobject:name (mapobjectclass)
 * mapobject:name()
 **
 * **Return value:** Name as set in the mapeditor of the ''mapobject''.
 *
 * **Note:** See [[scripting#map_get_objects|map_get_objects]] for getting
 * a mapobject object.
 */
static int map_object_get_name(lua_State *s)
{
    MapObject *obj = LuaMapObject::check(s, 1);
    push(s, obj->getName());
    return 1;
}

/** LUA mapobject:type (mapobjectclass)
 * mapobject:type()
 **
 * **Return value:** Type as set in the mapeditor of the ''mapobject''.
 *
 * **Note:** See [[scripting#map_get_objects|map_get_objects]] for getting
 * a mapobject object.
 */
static int map_object_get_type(lua_State *s)
{
    MapObject *obj = LuaMapObject::check(s, 1);
    push(s, obj->getType());
    return 1;
}


/** LUA_CATEGORY Item class (itemclass)
 */

/** LUA get_item_class (itemclass)
 * get_item_class(int itemid)
 * get_item_class(string itemname)
 **
 * **Return value:** This function returns a object of the item class.
 * See below for usage of that object.
 */
static int get_item_class(lua_State *s)
{
    LuaItemClass::push(s, checkItemClass(s, 1));
    return 1;
}

/** LUA itemclass:on (itemclass)
 * itemclass:on(string event, function callback)
 **
 * Assigns ''callback'' as callback for the ''event'' event.
 *
 * **Note:** See [[scripting#get_item_class|get_item_class]] for getting
 * a itemclass object.
 */
static int item_class_on(lua_State *s)
{
    ItemClass *itemClass = LuaItemClass::check(s, 1);
    const char *event = luaL_checkstring(s, 2);
    luaL_checktype(s, 3, LUA_TFUNCTION);
    itemClass->setEventCallback(event, getScript(s));
    return 0;
}

/** LUA itemclass:attacks (itemclass)
 * itemclass:attacks()
 **
 * **Return value:** Returns a list of all attacks the item offers.
 *
 * **See:** the [[scripting#AttackInfo Class|AttackInfo class]] for more info
 * about how to use the values in the list.
 */
static int item_class_attacks(lua_State *s)
{
    ItemClass *itemClass = LuaItemClass::check(s, 1);
    std::vector<AttackInfo *> attacks = itemClass->getAttackInfos();
    pushSTLContainer<AttackInfo *>(s, attacks);
    return 1;
}


/**
 * Returns four useless tables for testing the STL container push wrappers.
 * This function can be removed when there are more useful functions which use
 * them.
 */
static int test_tableget(lua_State *s)
{

    std::list<float> list;
    std::vector<std::string> svector;
    std::vector<int> ivector;
    std::map<std::string, std::string> map;
    std::set<int> set;

    LOG_INFO("Pushing Float List");
    list.push_back(12.636);
    list.push_back(0.0000000045656);
    list.push_back(185645445634566.346);
    list.push_back(7835458.11);
    pushSTLContainer<float>(s, list);

    LOG_INFO("Pushing String Vector");
    svector.push_back("All");
    svector.push_back("your");
    svector.push_back("base");
    svector.push_back("are");
    svector.push_back("belong");
    svector.push_back("to");
    svector.push_back("us!");
    pushSTLContainer<std::string>(s, svector);

    LOG_INFO("Pushing Integer Vector");
    ivector.resize(10);
    for (int i = 1; i < 10; i++)
    {
        ivector[i-1] = i * i;
    }
    pushSTLContainer<int>(s, ivector);

    LOG_INFO("Pushing String/String Map");
    map["Apple"] = "red";
    map["Banana"] = "yellow";
    map["Lime"] = "green";
    map["Plum"] = "blue";
    pushSTLContainer<std::string, std::string>(s, map);

    LOG_INFO("Pushing Integer Set");
    set.insert(12);
    set.insert(8);
    set.insert(14);
    set.insert(10);
    pushSTLContainer<int>(s, set);


    return 5;
}



static int require_loader(lua_State *s)
{
    // Add .lua extension (maybe only do this when it doesn't have it already)
    const char *file = luaL_checkstring(s, 1);
    std::string filename = file;
    filename.append(".lua");

    const std::string path = ResourceManager::resolve(filename);
    if (!path.empty())
        luaL_loadfile(s, path.c_str());
    else
        lua_pushliteral(s, "File not found");

    return 1;
}


LuaScript::LuaScript():
    nbArgs(-1)
{
    mRootState = luaL_newstate();
    mCurrentState = mRootState;
    luaL_openlibs(mRootState);

    // Register package loader that goes through the resource manager
    // package.loaders[2] = require_loader
    lua_getglobal(mRootState, "package");
#if LUA_VERSION_NUM < 502
    lua_getfield(mRootState, -1, "loaders");
#else
    lua_getfield(mRootState, -1, "searchers");
#endif
    lua_pushcfunction(mRootState, require_loader);
    lua_rawseti(mRootState, -2, 2);
    lua_pop(mRootState, 2);

    // Put the callback functions in the scripting environment.
    static luaL_Reg const callbacks[] = {
        { "on_update_derived_attribute",     &on_update_derived_attribute     },
        { "on_recalculate_base_attribute",   &on_recalculate_base_attribute   },
        { "on_character_death",              &on_character_death              },
        { "on_character_death_accept",       &on_character_death_accept       },
        { "on_character_login",              &on_character_login              },
        { "on_being_death",                  &on_being_death                  },
        { "on_being_remove",                 &on_being_remove                 },
        { "on_update",                       &on_update                       },
        { "on_create_npc_delayed",           &on_create_npc_delayed           },
        { "on_map_initialize",               &on_map_initialize               },
        { "on_craft",                        &on_craft                        },
        { "on_mapvar_changed",               &on_mapvar_changed               },
        { "on_worldvar_changed",             &on_worldvar_changed             },
        { "on_mapupdate",                    &on_mapupdate                    },
        { "get_item_class",                  &get_item_class                  },
        { "get_monster_class",               &get_monster_class               },
        { "get_status_effect",               &get_status_effect               },
        { "npc_create",                      &npc_create                      },
        { "npc_message",                     &npc_message                     },
        { "npc_choice",                      &npc_choice                      },
        { "npc_trade",                       &npc_trade                       },
        { "npc_post",                        &npc_post                        },
        { "npc_enable",                      &npc_enable                      },
        { "npc_disable",                     &npc_disable                     },
        { "chr_warp",                        &chr_warp                        },
        { "chr_get_inventory",               &chr_get_inventory               },
        { "chr_inv_change",                  &chr_inv_change                  },
        { "chr_inv_count",                   &chr_inv_count                   },
        { "chr_get_equipment",               &chr_get_equipment               },
        { "chr_equip_slot",                  &chr_equip_slot                  },
        { "chr_equip_item",                  &chr_equip_item                  },
        { "chr_unequip_slot",                &chr_unequip_slot                },
        { "chr_unequip_item",                &chr_unequip_item                },
        { "chr_get_level",                   &chr_get_level                   },
        { "chr_get_quest",                   &chr_get_quest                   },
        { "chr_set_quest",                   &chr_set_quest                   },
        { "chr_request_quest",               &chr_request_quest               },
        { "chr_try_get_quest",               &chr_try_get_quest               },
        { "getvar_map",                      &getvar_map                      },
        { "setvar_map",                      &setvar_map                      },
        { "getvar_world",                    &getvar_world                    },
        { "setvar_world",                    &setvar_world                    },
        { "chr_get_post",                    &chr_get_post                    },
        { "chr_get_exp",                     &chr_get_exp                     },
        { "chr_give_exp",                    &chr_give_exp                    },
        { "chr_get_rights",                  &chr_get_rights                  },
        { "chr_set_hair_style",              &chr_set_hair_style              },
        { "chr_get_hair_style",              &chr_get_hair_style              },
        { "chr_set_hair_color",              &chr_set_hair_color              },
        { "chr_get_hair_color",              &chr_get_hair_color              },
        { "chr_get_kill_count",              &chr_get_kill_count              },
        { "chr_give_special",                &chr_give_special                },
        { "chr_has_special",                 &chr_has_special                 },
        { "chr_take_special",                &chr_take_special                },
        { "chr_set_special_recharge_speed",  &chr_set_special_recharge_speed  },
        { "chr_get_special_recharge_speed",  &chr_get_special_recharge_speed  },
        { "chr_set_special_mana",            &chr_set_special_mana            },
        { "chr_get_special_mana",            &chr_get_special_mana            },
        { "chr_kick",                        &chr_kick                        },
        { "exp_for_level",                   &exp_for_level                   },
        { "monster_create",                  &monster_create                  },
        { "monster_get_name",                &monster_get_name                },
        { "monster_get_id",                  &monster_get_id                  },
        { "monster_change_anger",            &monster_change_anger            },
        { "monster_drop_anger",              &monster_drop_anger              },
        { "monster_get_angerlist",           &monster_get_angerlist           },
        { "monster_remove",                  &monster_remove                  },
        { "being_apply_status",              &being_apply_status              },
        { "being_remove_status",             &being_remove_status             },
        { "being_has_status",                &being_has_status                },
        { "being_set_status_time",           &being_set_status_time           },
        { "being_get_status_time",           &being_get_status_time           },
        { "being_get_gender",                &being_get_gender                },
        { "being_set_gender",                &being_set_gender                },
        { "being_type",                      &being_type                      },
        { "being_walk",                      &being_walk                      },
        { "being_say",                       &being_say                       },
        { "being_damage",                    &being_damage                    },
        { "being_heal",                      &being_heal                      },
        { "being_get_name",                  &being_get_name                  },
        { "being_get_action",                &being_get_action                },
        { "being_set_action",                &being_set_action                },
        { "being_get_direction",             &being_get_direction             },
        { "being_set_direction",             &being_set_direction             },
        { "being_apply_attribute_modifier",  &being_apply_attribute_modifier  },
        { "being_remove_attribute_modifier", &being_remove_attribute_modifier },
        { "being_set_base_attribute",        &being_set_base_attribute        },
        { "being_get_modified_attribute",    &being_get_modified_attribute    },
        { "being_get_base_attribute",        &being_get_base_attribute        },
        { "being_set_walkmask",              &being_set_walkmask              },
        { "being_get_walkmask",              &being_get_walkmask              },
        { "being_get_mapid",                 &being_get_mapid                 },
        { "posX",                            &posX                            },
        { "posY",                            &posY                            },
        { "trigger_create",                  &trigger_create                  },
        { "chat_message",                    &chat_message                    },
        { "get_beings_in_circle",            &get_beings_in_circle            },
        { "get_beings_in_rectangle",         &get_beings_in_rectangle         },
        { "get_character_by_name",           &get_character_by_name           },
        { "being_register",                  &being_register                  },
        { "effect_create",                   &effect_create                   },
        { "chr_shake_screen",                &chr_shake_screen                },
        { "chr_create_text_particle",        &chr_create_text_particle        },
        { "test_tableget",                   &test_tableget                   },
        { "get_map_id",                      &get_map_id                      },
        { "get_map_property",                &get_map_property                },
        { "is_walkable",                     &is_walkable                     },
        { "map_get_pvp",                     &map_get_pvp                     },
        { "item_drop",                       &item_drop                       },
        { "item_get_name",                   &item_get_name                   },
        { "npc_ask_integer",                 &npc_ask_integer                 },
        { "npc_ask_string",                  &npc_ask_string                  },
        { "log",                             &log                             },
        { "get_distance",                    &get_distance                    },
        { "map_get_objects",                 &map_get_objects                 },
        { "announce",                        &announce                        },
        { "get_special_info",                &get_special_info                },
        { NULL, NULL }
    };
#if LUA_VERSION_NUM < 502
    lua_pushvalue(mRootState, LUA_GLOBALSINDEX);
    luaL_register(mRootState, NULL, callbacks);
#else
    lua_pushglobaltable(mRootState);
    luaL_setfuncs(mRootState, callbacks, 0);
#endif
    lua_pop(mRootState, 1);                     // pop the globals table

    static luaL_Reg const members_AttackInfo[] = {
        { "priority",                        &attack_get_priority             },
        { "cooldowntime",                    &attack_get_cooldowntime         },
        { "warmuptime",                      &attack_get_warmuptime           },
        { "reusetime",                       &attack_get_reusetime            },
        { "damage",                          &attack_get_damage               },
        { "on_attack",                       &attack_on_attack                },
        { NULL, NULL }
    };

    static luaL_Reg const members_Damage[] = {
        { "id",                              &damage_get_id                   },
        { "skill",                           &damage_get_skill                },
        { "base",                            &damage_get_base                 },
        { "delta",                           &damage_get_delta                },
        { "cth",                             &damage_get_cth                  },
        { "element",                         &damage_get_element              },
        { "type",                            &damage_get_type                 },
        { "is_truestrike",                   &damage_is_truestrike            },
        { "range",                           &damage_get_range                },
        { NULL, NULL }
    };

    static luaL_Reg const members_ItemClass[] = {
        { "on",                              &item_class_on                   },
        { "attacks",                         &item_class_attacks              },
        { NULL, NULL }
    };

    static luaL_Reg const members_MapObject[] = {
        { "property",                        &map_object_get_property         },
        { "bounds",                          &map_object_get_bounds           },
        { "name",                            &map_object_get_name             },
        { "type",                            &map_object_get_type             },
        { NULL, NULL }
    };

    static luaL_Reg const members_MonsterClass[] = {
        { "on_update",                       &monster_class_on_update         },
        { "on_damage",                       &monster_class_on_damage         },
        { "attacks",                         &monster_class_attacks           },
        { NULL, NULL }
    };

    static luaL_Reg const members_StatusEffect[] = {
        { "on_tick",                         &status_effect_on_tick           },
        { NULL, NULL }
    };

    static luaL_Reg const members_SpecialInfo[] = {
        { "name",                            &specialinfo_get_name            },
        { "needed_mana",                     &specialinfo_get_needed_mana     },
        { "rechargeable",                    &specialinfo_is_rechargeable     },
        { "on_use",                          &specialinfo_on_use              },
        { "on_recharged",                    &specialinfo_on_recharged        },
        { "category",                        &specialinfo_get_category        },
        { NULL, NULL}
    };

    LuaAttackInfo::registerType(mRootState, "Attack", members_AttackInfo);
    LuaDamage::registerType(mRootState, "Damage", members_Damage);
    LuaItemClass::registerType(mRootState, "ItemClass", members_ItemClass);
    LuaMapObject::registerType(mRootState, "MapObject", members_MapObject);
    LuaMonsterClass::registerType(mRootState, "MonsterClass", members_MonsterClass);
    LuaStatusEffect::registerType(mRootState, "StatusEffect", members_StatusEffect);
    LuaSpecialInfo::registerType(mRootState, "SpecialInfo", members_SpecialInfo);

    // Make script object available to callback functions.
    lua_pushlightuserdata(mRootState, const_cast<char *>(&registryKey));
    lua_pushlightuserdata(mRootState, this);
    lua_rawset(mRootState, LUA_REGISTRYINDEX);

    // Push the error handler to first index of the stack
    lua_getglobal(mRootState, "debug");
    lua_getfield(mRootState, -1, "traceback");
    lua_remove(mRootState, 1);                  // remove the 'debug' table

    loadFile("scripts/lua/libmana.lua");
}