g_ai_lua.cpp

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/*
Copyright (C) 2002-2020 UFO: Alien Invasion.

This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; 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 this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.

*/

#include "../shared/cxx.h"

#include "g_local.h"
#include "g_ai.h"
#include "g_actor.h"
#include "g_client.h"
#include "g_combat.h"
#include "g_edicts.h"
#include "g_health.h"
#include "g_move.h"
#include "g_utils.h"
#include "g_vis.h"
extern "C" {
#include <lauxlib.h>
}

#define POS3_METATABLE  "pos3" 
#define ACTOR_METATABLE "actor" 
#define AI_METATABLE    "ai" 
static lua_State* ailState;

#define luaL_dobuffer(L, b, n, s) \
    (luaL_loadbuffer(L, b, n, s) || lua_pcall(L, 0, LUA_MULTRET, 0))
#define AIL_invalidparameter(n) \
    gi.DPrintf("AIL: Invalid parameter #%d in '%s'.\n", n, __func__)

typedef enum {
    AILVT_ALL,      /* Don't do vis checks (god's view) */
    AILVT_SIGHT,    /* Standard vis check */
    AILVT_TEAM,     /* Team vis check */
    AILVT_DIST      /* Check only vis distance */
} ailVisType_t;

typedef enum {
    AILSC_DIST,     /* Sort by line distance */
    AILSC_PATH,     /* Sort by pathing cost */
    AILSC_HP        /* Sort by HP */
} ailSortCritType_t;

typedef enum {
    AILSP_FAST,     /* Fastest to get to */
    AILSP_NEAR,     /* Nearest to target */
    AILSP_FAR,      /* Farthest from target (within weapon's range) */
    AILSP_DMG       /* Best expected damage */
} ailShootPosType_t;

typedef enum {
    AILPW_RAND,     /* Wander randomly */
    AILPW_CW,       /* Move clockwise */
    AILPW_CCW       /* Move counter-clockwise */
} ailWanderPosType;
/*
 * Helper functions
 */

static const char* AIL_toTeamString (const int team)
{
    const char* teamStr = gi.GetConstVariable("luaaiteam", team);
    if (teamStr == nullptr)
        AIL_invalidparameter(1);
    return teamStr;
}

static int AIL_toTeamInt (const char* team, const int param)
{
    int teamInt = TEAM_DEFAULT;
    if (!gi.GetConstIntFromNamespace("luaaiteam", team, &teamInt))
        AIL_invalidparameter(param);
    return teamInt;
}

static ailVisType_t AIL_toVisInt (lua_State* L, const int index)
{
    int visInt = AILVT_ALL;
    if (lua_isstring(L, index)) {
        const char* s = lua_tostring(L, index);
        if (!gi.GetConstIntFromNamespace("luaaivis", s, &visInt))
            AIL_invalidparameter(index);
    } else
        AIL_invalidparameter(index);
    return static_cast<ailVisType_t> (visInt);
}

static ailSortCritType_t AIL_toSortInt (lua_State* L, const int index)
{
    int sortInt = AILSC_DIST;
    if (lua_isstring(L, index)) {
        const char* s = lua_tostring(L, index);
        if (!gi.GetConstIntFromNamespace("luaaisort", s, &sortInt))
            AIL_invalidparameter(index);
    } else
        AIL_invalidparameter(index);
    return static_cast<ailSortCritType_t> (sortInt);
}

static ailSortCritType_t AIL_toDistInt (lua_State* L, const int index)
{
    int distInt = AILSC_DIST;
    if (lua_isstring(L, index)) {
        const char* s = lua_tostring(L, index);
        if (!gi.GetConstIntFromNamespace("luaaidist", s, &distInt))
            AIL_invalidparameter(index);
    } else
        AIL_invalidparameter(index);
    return static_cast<ailSortCritType_t> (distInt);
}

static ailShootPosType_t AIL_toShotPInt (lua_State* L, const int index)
{
    int spInt = AILSP_FAST;
    if (lua_isstring(L, index)) {
        const char* s = lua_tostring(L, index);
        if (!gi.GetConstIntFromNamespace("luaaishot", s, &spInt))
            AIL_invalidparameter(index);
    } else
        AIL_invalidparameter(index);
    return static_cast<ailShootPosType_t> (spInt);
}

static ailWanderPosType AIL_toWanderPInt (lua_State* L, const int index)
{
    int wpInt = AILPW_RAND;
    if (lua_isstring(L, index)) {
        const char* s = lua_tostring(L, index);
        if (!gi.GetConstIntFromNamespace("luaaiwander", s, &wpInt))
            AIL_invalidparameter(index);
    } else
        AIL_invalidparameter(index);
    return static_cast<ailWanderPosType> (wpInt);
}

typedef struct aiActor_s {
    Actor* actor; 
} aiActor_t;


/* Table sorting */
template<typename T>
struct AilSortTable {
    T data;
    float sortLookup;
};

template<typename T>
bool operator< (AilSortTable<T> i, AilSortTable<T> j) {
        return (i.sortLookup < j.sortLookup);
}

/*
 * Current AI Actor.
 */
static Actor* AIL_ent; 
static Player* AIL_player; 
static float AIL_GetBestShot(const Actor& shooter, const Actor& target, const int tu, const float dist, shoot_types_t& bestType, fireDefIndex_t& bestFd, int& bestShots)
{
    int shotChecked = NONE;
    float bestDmg = 0.0f;
    bestShots = bestType = bestFd = NONE;
    for (shoot_types_t shootType = ST_RIGHT; shootType < ST_NUM_SHOOT_TYPES; shootType++) {
        const Item* item = AI_GetItemForShootType(shootType, AIL_ent);
        if (item == nullptr)
            continue;

        const fireDef_t* fdArray = item->getFiredefs();
        if (fdArray == nullptr)
            continue;

        for (fireDefIndex_t fdIdx = 0; fdIdx < item->ammoDef()->numFiredefs[fdArray->weapFdsIdx]; fdIdx++) {
            const fireDef_t* fd = &fdArray[fdIdx];
            const int time = G_ActorGetModifiedTimeForFiredef(AIL_ent, fd, false);
            /* how many shoots can this actor do */
            const int shots = tu / time;

            if (!shots)
                continue;

            if (!AI_FighterCheckShoot(AIL_ent, &target, fd, dist))
                continue;

            const int shotFlags = fd->gravity | (fd->launched << 1) | (fd->rolled << 2);
            if (shotChecked != shotFlags) {
                shotChecked = shotFlags;
                if (!AI_CheckLineOfFire(AIL_ent, &target, fd, shots))
                    continue;
            }

            /* Check if we can do the most damage here */
            float dmg = AI_CalcShotDamage(AIL_ent, &target, fd, shootType) * shots;
            if (dmg > bestDmg) {
                bestDmg = dmg;
                bestShots = shots;
                bestFd = fdIdx;
                bestType = shootType;
            }
        }
    }

    return bestDmg;
}

/*
 * Actor metatable.
 */
/* Internal functions. */
static int actorL_register(lua_State* L);
static int lua_isactor(lua_State* L, int index);
static aiActor_t* lua_toactor(lua_State* L, int index);
static aiActor_t* lua_pushactor(lua_State* L, aiActor_t* actor);
/* Metatable functions. */
static int actorL_tostring(lua_State* L);
static int actorL_pos(lua_State* L);
static int actorL_shoot(lua_State* L);
static int actorL_team(lua_State* L);
static int actorL_throwgrenade(lua_State* L);
static int actorL_TU(lua_State* L);
static int actorL_HP(lua_State* L);
static int actorL_morale(lua_State* L);
static int actorL_isinjured(lua_State* L);
static int actorL_isarmed(lua_State* L);
static int actorL_isdead(lua_State* L);
static int actorL_isvalidtarget(lua_State* L);
static const luaL_reg actorL_methods[] = {
    {"__tostring", actorL_tostring},
    {"pos", actorL_pos},
    {"shoot", actorL_shoot},
    {"team", actorL_team},
    {"throwgrenade", actorL_throwgrenade},
    {"TU", actorL_TU},
    {"HP", actorL_HP},
    {"morale", actorL_morale},
    {"isinjured", actorL_isinjured},
    {"isarmed", actorL_isarmed},
    {"isdead", actorL_isdead},
    {"isvalidtarget", actorL_isvalidtarget},
    {nullptr, nullptr}
};

/* Internal functions. */
static int pos3L_register(lua_State* L);
static int lua_ispos3(lua_State* L, int index);
static pos3_t* lua_topos3(lua_State* L, int index);
static pos3_t* lua_pushpos3(lua_State* L, pos3_t* pos);
/* Metatable functions. */
static int pos3L_tostring(lua_State* L);
static int pos3L_goto(lua_State* L);
static int pos3L_face(lua_State* L);
static int pos3L_distance(lua_State* L);
static const luaL_reg pos3L_methods[] = {
    {"__tostring", pos3L_tostring},
    {"goto", pos3L_goto},
    {"face", pos3L_face},
    {"distance", pos3L_distance},
    {nullptr, nullptr}
};


static int AIL_print(lua_State* L);
static int AIL_squad(lua_State* L);
static int AIL_select(lua_State* L);
static int AIL_see(lua_State* L);
static int AIL_crouch(lua_State* L);
static int AIL_reactionfire(lua_State* L);
static int AIL_roundsleft(lua_State* L);
static int AIL_canreload(lua_State* L);
static int AIL_reload(lua_State* L);
static int AIL_positionshoot(lua_State* L);
static int AIL_positionhide(lua_State* L);
static int AIL_positionherd(lua_State* L);
static int AIL_positionapproach(lua_State* L);
static int AIL_grabweapon(lua_State* L);
static int AIL_missiontargets(lua_State* L);
static int AIL_waypoints(lua_State* L);
static int AIL_positionmission(lua_State* L);
static int AIL_positionwander(lua_State* L);
static int AIL_findweapons(lua_State* L);
static int AIL_isfighter(lua_State* L);
static int AIL_setwaypoint(lua_State* L);
static int AIL_difficulty(lua_State* L);
static int AIL_positionflee(lua_State* L);
static int AIL_weapontype(lua_State* L);
static int AIL_actor(lua_State* L);
static int AIL_tusforshooting(lua_State* L);
static int AIL_class(lua_State* L);
static int AIL_hideneeded(lua_State* L);

static const luaL_reg AIL_methods[] = {
    {"print", AIL_print},
    {"squad", AIL_squad},
    {"select", AIL_select},
    {"see", AIL_see},
    {"crouch", AIL_crouch},
    {"reactionfire", AIL_reactionfire},
    {"roundsleft", AIL_roundsleft},
    {"canreload", AIL_canreload},
    {"reload", AIL_reload},
    {"positionshoot", AIL_positionshoot},
    {"positionhide", AIL_positionhide},
    {"positionherd", AIL_positionherd},
    {"positionapproach", AIL_positionapproach},
    {"grabweapon", AIL_grabweapon},
    {"missiontargets", AIL_missiontargets},
    {"waypoints", AIL_waypoints},
    {"positionmission", AIL_positionmission},
    {"positionwander", AIL_positionwander},
    {"findweapons", AIL_findweapons},
    {"isfighter", AIL_isfighter},
    {"setwaypoint", AIL_setwaypoint},
    {"difficulty", AIL_difficulty},
    {"positionflee", AIL_positionflee},
    {"weapontype", AIL_weapontype},
    {"actor", AIL_actor},
    {"tusforshooting", AIL_tusforshooting},
    {"class", AIL_class},
    {"hideneeded", AIL_hideneeded},
    {nullptr, nullptr}
};


static int actorL_register (lua_State* L)
{
    /* Create the metatable */
    luaL_newmetatable(L, ACTOR_METATABLE);

    /* Create the access table */
    lua_pushvalue(L, -1);
    lua_setfield(L, -2, "__index");

    /* Register the values */
    luaL_register(L, nullptr, actorL_methods);

    /* Clean up stack. */
    lua_pop(L, 1);

    return 0; /* No error */
}

static int lua_isactor (lua_State* L, int index)
{
    if (lua_getmetatable(L, index) == 0)
        return 0;
    lua_getfield(L, LUA_REGISTRYINDEX, ACTOR_METATABLE);

    int ret = 0;
    if (lua_rawequal(L, -1, -2))  /* does it have the correct metatable? */
        ret = 1;

    lua_pop(L, 2);  /* remove both metatables */
    return ret;
}

static aiActor_t* lua_toactor (lua_State* L, int index)
{
    if (lua_isactor(L, index)) {
        return (aiActor_t*) lua_touserdata(L, index);
    }
    luaL_typerror(L, index, ACTOR_METATABLE);
    return nullptr;
}

static aiActor_t* lua_pushactor (lua_State* L, aiActor_t* actor)
{
    aiActor_t* a = (aiActor_t*) lua_newuserdata(L, sizeof(aiActor_t));
    *a = *actor;
    luaL_getmetatable(L, ACTOR_METATABLE);
    lua_setmetatable(L, -2);
    return a;
}

static int actorL_tostring (lua_State* L)
{
    char buf[MAX_VAR];

    assert(lua_isactor(L, 1));

    const aiActor_t* target = lua_toactor(L, 1);
    Com_sprintf(buf, sizeof(buf), "Actor( %s )", target->actor->chr.name);

    lua_pushstring(L, buf);
    return 1;
}

static int actorL_pos (lua_State* L)
{
    assert(lua_isactor(L, 1));

    const aiActor_t* target = lua_toactor(L, 1);
    lua_pushpos3(L, &target->actor->pos);
    return 1;
}

static int actorL_shoot (lua_State* L)
{
    assert(lua_isactor(L, 1));

    /* Target */
    const aiActor_t* target = lua_toactor(L, 1);

    /* Number of TU to spend shooting, fire mode will adjust to that. */
    int tu = AIL_ent->getUsableTUs();
    if (lua_gettop(L) > 1) {
        assert(lua_isnumber(L, 2)); /* Must be a number. */

        tu = std::min(static_cast<int>(lua_tonumber(L, 2)), tu);
    }

    const float dist = VectorDist(AIL_ent->origin, target->actor->origin);
    shoot_types_t bestType = NONE;
    fireDefIndex_t bestFd = NONE;
    int bestShots = 0;
    AIL_GetBestShot(*AIL_ent, *target->actor, tu, dist, bestType, bestFd, bestShots);

    /* Failure - no weapon. */
    if (bestType == NONE) {
        lua_pushboolean(L, 0);
        return 1;
    }

    bool shot = false;
    while (bestShots > 0) {
        if (G_IsDead(target->actor))
            break;
        bestShots--;
        shot = G_ClientShoot(*AIL_player, AIL_ent, target->actor->pos, bestType, bestFd, nullptr, true, 0) || shot;
    }

    /* Success? */
    lua_pushboolean(L, shot);
    return 1;
}

static int actorL_team (lua_State* L)
{
    assert(lua_isactor(L, 1));

    const aiActor_t* target = lua_toactor(L, 1);
    assert(target != nullptr);
    const char* team = AIL_toTeamString(target->actor->getTeam());
    lua_pushstring(L, team);
    return 1;
}

static int actorL_throwgrenade(lua_State* L)
{
    /* check parameter */
    if (!(lua_gettop(L) && lua_isactor(L, 1))) {
        AIL_invalidparameter(1);
        lua_pushboolean(L, 0);
        return 1;
    }
    const aiActor_t* target = lua_toactor(L, 1);
    assert(target != nullptr);

    /* Min number of enemies to use grenade */
    int minNum = 0;
    if (lua_gettop(L) > 1) {
        if (!lua_isnumber(L, 2)) { /* Must be a number. */
            AIL_invalidparameter(2);
            lua_pushboolean(L, 0);
            return 1;
        }
        minNum = static_cast<int>(lua_tonumber(L, 2));
    }

    /* Number of TU to spend */
    int tus = AIL_ent->getUsableTUs();
    if (lua_gettop(L) > 2) {
        if (!lua_isnumber(L, 3)) { /* Must be a number. */
            AIL_invalidparameter(3);
            lua_pushboolean(L, 0);
            return 1;
        }
        tus = std::min(static_cast<int>(lua_tonumber(L, 3)), tus);
    }

    /* Check that we have a free hand */
    containerIndex_t hand = CID_RIGHT;
    const Item* right = AIL_ent->getRightHandItem();
    if (right)
        hand = right->isHeldTwoHanded() || AIL_ent->getLeftHandItem() ? CID_MAX : CID_LEFT;
    if (hand >= CID_MAX) {
        lua_pushboolean(L, 0);
        return 1;
    }

    /* Check if we have a grenade */
    Item* grenade = nullptr;
    const invDef_t* fromCont = AI_SearchGrenade(AIL_ent, &grenade);
    if (!fromCont || !grenade) {
        lua_pushboolean(L, 0);
        return 1;
    }
    /* Now check if we can use it */
    const fireDef_t* fdArray = grenade->getFiredefs();
    const int invMoveCost = fromCont->out + INVDEF(hand)->in;
    const shoot_types_t shotType = hand == CID_RIGHT ? ST_RIGHT : ST_LEFT;
    float dist = VectorDist(AIL_ent->origin, target->actor->origin);
    const fireDef_t* bestFd = nullptr;
    for (fireDefIndex_t fdIdx = 0; fdIdx < grenade->ammoDef()->numFiredefs[fdArray->weapFdsIdx]; fdIdx++) {
        const fireDef_t* fd = &fdArray[fdIdx];
        const int time = invMoveCost + G_ActorGetModifiedTimeForFiredef(AIL_ent, fd, false);
        /* Enough TU? */
        if (time > tus)
            continue;
        /* In range? */
        if (!AI_FighterCheckShoot(AIL_ent, target->actor, fd, dist))
            continue;
        /* LOF? */
        if (!AI_CheckLineOfFire(AIL_ent, target->actor, fd, 1))
            continue;

        /* Select the first usable firemode */
        bestFd = fd;
        break;
    }
    if (!bestFd) {
        lua_pushboolean(L, 0);
        return 1;
    }

    /* Finally check if we want to use it now */
    if (bestFd->splrad > 0) {
        Actor* check = nullptr;
        int n = 0;
        while ((check = G_EdictsGetNextLivingActor(check))) {
            /* check for distance */
            dist = VectorDist(target->actor->origin, check->origin);
            dist = dist > UNIT_SIZE / 2 ? dist - UNIT_SIZE / 2 : 0;
            if (dist > bestFd->splrad)
                continue;

            if (!AI_IsHostile(AIL_ent, target->actor)) {
                lua_pushboolean(L, 0);
                return 1;
            }
            ++n;
        }
        /* Check there's large enough group of targets */
        if (n < minNum) {
            lua_pushboolean(L, 0);
            return 1;
        }
    }

    /* Try to move the grenade to the free hand */
    if(!G_ActorInvMove(AIL_ent, fromCont, grenade, INVDEF(hand), NONE, NONE, true)) {
        lua_pushboolean(L, 0);
        return 1;
    }
    /* All right use it! */
    const bool result = G_ClientShoot(*AIL_player, AIL_ent, target->actor->pos, shotType, bestFd->fdIdx, nullptr, true, 0);

    lua_pushboolean(L, result);
    return 1;
}

static int actorL_TU (lua_State* L)
{
    /* check parameter */
    if (!(lua_gettop(L) && lua_isactor(L, 1))) {
        AIL_invalidparameter(1);
        lua_pushboolean(L, 0);
        return 1;
    }
    const aiActor_t* actor = lua_toactor(L, 1);
    assert(actor != nullptr);

    lua_pushnumber(L, actor->actor->getUsableTUs());
    return 1;
}

static int actorL_HP (lua_State* L)
{
    /* check parameter */
    if (!(lua_gettop(L) && lua_isactor(L, 1))) {
        AIL_invalidparameter(1);
        lua_pushboolean(L, 0);
        return 1;
    }
    const aiActor_t* actor = lua_toactor(L, 1);
    assert(actor != nullptr);

    lua_pushnumber(L, actor->actor->HP);
    return 1;
}

static int actorL_morale (lua_State* L)
{
    /* check parameter */
    if (!(lua_gettop(L) && lua_isactor(L, 1))) {
        AIL_invalidparameter(1);
        lua_pushboolean(L, 0);
        return 1;
    }
    const aiActor_t* actor = lua_toactor(L, 1);
    assert(actor != nullptr);

    const char* morStat = "normal";
    if (actor->actor->isPanicked())
        morStat = "panic";
    else if (actor->actor->isInsane())
        morStat = "insane";
    else if (actor->actor->isRaged())
        morStat = "rage";
    else if (actor->actor->getMorale() <= mor_brave->integer)
        morStat = "cower";

    lua_pushstring(L, morStat);
    return 1;
}

static int actorL_isinjured (lua_State* L)
{
    /* check parameter */
    if (!(lua_gettop(L) && lua_isactor(L, 1))) {
        AIL_invalidparameter(1);
        lua_pushboolean(L, 0);
        return 1;
    }
    const aiActor_t* actor = lua_toactor(L, 1);
    assert(actor != nullptr);

    lua_pushboolean(L, G_IsActorWounded(actor->actor, true)
            || actor->actor->HP <= actor->actor->chr.maxHP * 0.5);
    return 1;
}

static int actorL_isarmed (lua_State* L)
{
    /* check parameter */
    if (!(lua_gettop(L) && lua_isactor(L, 1))) {
        AIL_invalidparameter(1);
        lua_pushboolean(L, 0);
        return 1;
    }
    const aiActor_t* actor = lua_toactor(L, 1);
    assert(actor != nullptr);

    lua_pushboolean(L, actor->actor->getRightHandItem() ? 1 : 0);
    lua_pushboolean(L, actor->actor->getLeftHandItem() ? 1 : 0);
    return 2;
}

static int actorL_isdead (lua_State* L)
{
    /* check parameter */
    if (!(lua_gettop(L) && lua_isactor(L, 1))) {
        AIL_invalidparameter(1);
        lua_pushboolean(L, 0);
        return 1;
    }
    const aiActor_t* actor = lua_toactor(L, 1);
    assert(actor != nullptr);

    lua_pushboolean(L, actor->actor->isDead());
    return 1;
}

static int actorL_isvalidtarget (lua_State* L)
{
    assert(lua_isactor(L, 1));

    const aiActor_t* target = lua_toactor(L, 1);
    assert(target != nullptr);
    lua_pushboolean(L, AI_IsHostile(AIL_ent, target->actor));
    return 1;
}


static int pos3L_register (lua_State* L)
{
    /* Create the metatable */
    luaL_newmetatable(L, POS3_METATABLE);

    /* Create the access table */
    lua_pushvalue(L, -1);
    lua_setfield(L, -2, "__index");

    /* Register the values */
    luaL_register(L, nullptr, pos3L_methods);

    /* Clean up the stack. */
    lua_pop(L, 1);

    return 0; /* No error */
}

static int lua_ispos3 (lua_State* L, int index)
{
    if (lua_getmetatable(L, index) == 0)
        return 0;
    lua_getfield(L, LUA_REGISTRYINDEX, POS3_METATABLE);

    int ret = 0;
    if (lua_rawequal(L, -1, -2))  /* does it have the correct metatable? */
        ret = 1;

    lua_pop(L, 2);  /* remove both metatables */
    return ret;
}

static pos3_t* lua_topos3 (lua_State* L, int index)
{
    if (lua_ispos3(L, index)) {
        return (pos3_t*) lua_touserdata(L, index);
    }
    luaL_typerror(L, index, POS3_METATABLE);
    return nullptr;
}

static pos3_t* lua_pushpos3 (lua_State* L, pos3_t* pos)
{
    pos3_t* p = (pos3_t*) lua_newuserdata(L, sizeof(pos3_t));
    memcpy(p, pos, sizeof(*p));
    luaL_getmetatable(L, POS3_METATABLE);
    lua_setmetatable(L, -2);
    return p;
}

static int pos3L_tostring (lua_State* L)
{
    char buf[MAX_VAR];

    assert(lua_ispos3(L, 1));

    const pos3_t* p = lua_topos3(L, 1);
    Com_sprintf(buf, sizeof(buf), "Pos3( x=%d, y=%d, z=%d )", (*p)[0], (*p)[1], (*p)[2]);

    lua_pushstring(L, buf);
    return 1;
}

static int pos3L_goto (lua_State* L)
{
    assert(lua_ispos3(L, 1));

    /* Calculate move table. */
    G_MoveCalc(0, AIL_ent, AIL_ent->pos, AIL_ent->getUsableTUs());
    gi.MoveStore(level.pathingMap);

    /* Move. */
    const pos3_t* pos = lua_topos3(L, 1);
    /* do the move */
    for (;;) {
        if (AIL_ent->isDead())
            break;
        G_ClientMove(*AIL_player, 0, AIL_ent, *pos);
        if (AIL_ent->isSamePosAs(*pos))
            break;
        const pos_t length = G_ActorMoveLength(AIL_ent, level.pathingMap, *pos, false);
        if (length > AIL_ent->getUsableTUs() || length >= ROUTING_NOT_REACHABLE)
            break;
    }

    lua_pushboolean(L, AIL_ent->isSamePosAs(*pos));
    return 1;
}

static int pos3L_face (lua_State* L)
{
    assert(lua_ispos3(L, 1));

    const pos3_t* pos = lua_topos3(L, 1);
    AI_TurnIntoDirection(AIL_ent, *pos);

    lua_pushboolean(L, 1);
    return 1;
}

static int pos3L_distance (lua_State* L)
{
    assert(lua_ispos3(L, 1));

    pos3_t* pos = lua_topos3(L, 1);
    assert(pos != nullptr);

    ailSortCritType_t distType = AILSC_DIST;
    if (lua_gettop(L) > 1)
        distType = AIL_toDistInt(L, 2);

    switch (distType) {
    case AILSC_PATH:
        /* Find a path to the target pos */
        if (!G_FindPath(0, AIL_ent, AIL_ent->pos, *pos, AIL_ent->isCrouched(), ROUTING_NOT_REACHABLE - 1)) {
            lua_pushnumber(L, ROUTING_NOT_REACHABLE);
            return 1;
        }
        lua_pushnumber(L, G_ActorMoveLength(AIL_ent, level.pathingMap, *pos, false));
        return 1;
    case AILSC_DIST:
    default:
        vec3_t to;
        PosToVec(*pos, to);
        lua_pushnumber(L, VectorDist(AIL_ent->origin, to));
        return 1;
    }
}

/*
 * General functions.
 */

static int AIL_print (lua_State* L)
{
    const int n = lua_gettop(L);  /* number of arguments */

    for (int i = 1; i <= n; i++) {
        const char* s;
        bool meta = false;

        lua_pushvalue(L, i);   /* value to print */
        if (luaL_callmeta(L, -1, "__tostring")) {
            s = lua_tostring(L, -1);
            meta = true;
        } else {
            switch (lua_type(L, -1)) {
            case LUA_TNUMBER:
            case LUA_TSTRING:
                s = lua_tostring(L, -1);
                break;
            case LUA_TBOOLEAN:
                s = lua_toboolean(L, -1) ? "true" : "false";
                break;
            case LUA_TNIL:
                s = "nil";
                break;

            default:
                s = "unknown lua type";
                break;
            }
        }
        gi.DPrintf("%s%s", (i > 1) ? "\t" : "", s);
        lua_pop(L, 1); /* Pop the value */
        if (meta) /* Meta creates an additional string. */
            lua_pop(L, 1);
    }

    gi.DPrintf("\n");
    return 0;
}

/*
 * Player functions.
 */

static int AIL_squad (lua_State* L)
{
    if (g_ailua->integer < 2) {
        gi.DPrintf("Problem while running lua: attempt to get the player's team while not in team mode.");
        lua_pushnil(L);
        return 1;
    }

    /* New Lua table. */
    lua_newtable(L);

    int i = 1; /* LUA indexes starting from one */
    Actor* check = nullptr;
    while ((check = G_EdictsGetNextActor(check))) {
        if (check->getPlayerNum() != AIL_player->getNum())
            continue;
        lua_pushnumber(L, i++); /* index */
        aiActor_t target;
        target.actor = check;
        lua_pushactor(L, &target); /* value */
        lua_rawset(L, -3); /* store the value in the table */
    }
    return 1; /* Returns the table of actors. */
}

static int AIL_select (lua_State* L)
{
    if (g_ailua->integer < 2) {
        gi.DPrintf("Problem while running lua: attempt to select the active AI actor while not in team mode.");
        lua_pushnil(L);
    } else if (lua_gettop(L) > 0 && lua_isactor(L, 1)) {
        aiActor_t* target = lua_toactor(L, 1);
        if (target->actor->getPlayerNum() == AIL_player->getNum())
            AIL_ent = target->actor;
        lua_pushboolean(L, AIL_ent == target->actor);
    } else {
        AIL_invalidparameter(1);
        lua_pushboolean(L, false);
    }
    return 1;
}

/*
 * Actor functions
 */

static int AIL_see (lua_State* L)
{
    /* Defaults. */
    int team = TEAM_ALL;
    ailVisType_t vision = AILVT_ALL;
    ailSortCritType_t sortCrit = AILSC_DIST;
    bool invTeam = false;

    /* Handle parameters. */
    if ((lua_gettop(L) > 0)) {
        /* Get what to "see" with. */
        vision = AIL_toVisInt(L, 1);

        /* We now check for different teams. */
        if ((lua_gettop(L) > 1)) {
            if (lua_isstring(L, 2)) {
                const char* s = lua_tostring(L, 2);
                if (s[0] == '-' || s[0] == '~') {
                    invTeam = true;
                    ++s;
                }
                team = AIL_toTeamInt(s, 2);
                /* Trying to see no one? */
                if (team == TEAM_ALL && invTeam)
                    AIL_invalidparameter(2);
            } else
                AIL_invalidparameter(2);
        }

        /* Sorting criteria */
        if ((lua_gettop(L) > 2)) {
            sortCrit = AIL_toSortInt(L, 3);
        }
    }

    int n = 0;
    Actor* check = nullptr;
    AilSortTable<Actor*> sortTable[MAX_EDICTS];
    /* Get visible things. */
    const int visDist = G_VisCheckDist(AIL_ent);
    /* We are about to check the team view, update it accordingly */
    if (vision == AILVT_TEAM)
        G_CheckVisTeamAll(AIL_ent->getTeam(), VT_NOFRUSTUM, AIL_ent);
    while ((check = G_EdictsGetNextLivingActor(check))) {
        if (AIL_ent == check)
            continue;
        const float distance = VectorDistSqr(AIL_ent->pos, check->pos);
        /* Check for team match if needed. */
        if ((team == TEAM_ALL || (check->getTeam() == team ? !invTeam : invTeam))
                && (vision == AILVT_ALL
                || (vision == AILVT_SIGHT && G_Vis(AIL_ent->getTeam(), AIL_ent, check, VT_NOFRUSTUM))
                || (vision == AILVT_TEAM && G_IsVisibleForTeam(check, AIL_ent->getTeam()))
                || (vision == AILVT_DIST && distance <= visDist * visDist))) {
            switch (sortCrit) {
            case AILSC_PATH:
            {
                pos_t move = ROUTING_NOT_REACHABLE;
                if (G_FindPath(0, AIL_ent, AIL_ent->pos, check->pos, false, 0xFE))
                    move = gi.MoveLength(level.pathingMap, check->pos, 0, false);
                sortTable[n].sortLookup = move;
            }
                break;
            case AILSC_HP:
                sortTable[n].sortLookup = check->HP;
                break;
            case AILSC_DIST:
            default:
                sortTable[n].sortLookup = VectorDistSqr(AIL_ent->pos, check->pos);
                break;
            }
            sortTable[n++].data = check;
        }
    }

    /* Sort by given criterion - lesser first. */
    std::sort(sortTable, sortTable + n);

    /* Now save it in a Lua table. */
    lua_newtable(L);
    for (int i = 0; i < n; i++) {
        lua_pushnumber(L, i + 1); /* index, starts with 1 */
        aiActor_t target;
        target.actor = sortTable[i].data;
        lua_pushactor(L, &target); /* value */
        lua_rawset(L, -3); /* store the value in the table */
    }
    return 1; /* Returns the table of actors. */
}

static int AIL_crouch (lua_State* L)
{
    if (lua_gettop(L) > 0) {
        if (lua_isboolean(L, 1)) {
            const bool reqState = lua_toboolean(L, 1);
            const bool state = AIL_ent->isCrouched();
            if (reqState != state)
                G_ClientStateChange(*AIL_player, AIL_ent, STATE_CROUCHED, true);
        } else
            AIL_invalidparameter(1);
    }

    lua_pushboolean(L, AIL_ent->isCrouched());
    return 1;
}

static int AIL_reactionfire (lua_State* L)
{
    if (lua_gettop(L) > 0) {
        int reactionState = 0;

        if (lua_isstring(L, 1)) {
            /* get reaction fire mode */
            const char* cmd = lua_tostring(L, 1);
            reactionState = Q_streq(cmd, "disable") ? ~STATE_REACTION : STATE_REACTION;
        }

        if (reactionState) {
            G_ClientStateChange(*AIL_player, AIL_ent, reactionState, true);
        } else {
            AIL_invalidparameter(1);
        }
    }

    lua_pushboolean(L, AIL_ent->isReaction());
    return 1;
}

static int AIL_roundsleft (lua_State* L)
{
    /* Right hand */
    const Item* rightHand = AIL_ent->getRightHandItem();
    if (rightHand && (rightHand->def()->ammo < 1 || rightHand->getAmmoLeft() > 0))
        lua_pushnumber(L, rightHand->getAmmoLeft());
    else
        /* Currently unusable */
        lua_pushnil(L);

    /* Left hand */
    const Item* leftHand = AIL_ent->getLeftHandItem();
    if (leftHand && (leftHand->def()->ammo < 1 || leftHand->getAmmoLeft() > 0))
        lua_pushnumber(L, leftHand->getAmmoLeft());
    else
        lua_pushnil(L);
    return 2;
}

static int AIL_canreload (lua_State* L)
{
    lua_pushboolean(L, G_ClientCanReload(AIL_ent, CID_RIGHT));
    lua_pushboolean(L, G_ClientCanReload(AIL_ent, CID_LEFT));
    return 2;
}

static int AIL_reload (lua_State* L)
{
    containerIndex_t container = CID_RIGHT; /* Default to right hand. */

    if (lua_gettop(L) > 0) {
        if (lua_isstring(L, 1)) {
            const char* s = lua_tostring(L, 1);

            if (Q_streq(s, "right")) {
                container = CID_RIGHT;
            } else if (Q_streq(s, "left")) {
                container = CID_LEFT;
            } else {
                AIL_invalidparameter(1);
                return 0;
            }
        } else {
            AIL_invalidparameter(1);
            return 0;
        }
    }

    AI_TryToReloadWeapon(AIL_ent, container);
    return 0;
}

static int AIL_grabweapon (lua_State* L)
{
    lua_pushboolean(L, G_ClientGetWeaponFromInventory(AIL_ent));
    return 1;
}

static int AIL_positionshoot (lua_State* L)
{
    /* We need a target. */
    assert(lua_isactor(L, 1));
    aiActor_t* target = lua_toactor(L, 1);

    /* Make things more simple. */
    Actor* actor = AIL_ent;

    /* Shooting strategy */
    ailShootPosType_t posType = AILSP_FAST;
    if ((lua_gettop(L) > 1))
        posType = AIL_toShotPInt(L, 2);

    /* Number of TU to spend shooting, to make sure we have enough tus to actually fire. */
    int tus = actor->getUsableTUs();
    if (lua_gettop(L) > 2) {
        assert(lua_isnumber(L, 3)); /* Must be a number. */

        tus = std::min(static_cast<int>(lua_tonumber(L, 3)), tus);
    }

    /* Don't shoot units under our control */
    if (!AI_IsHostile(actor, target->actor)) {
        lua_pushboolean(L, 0);
        return 1;
    }

    shoot_types_t shootType = ST_RIGHT;
    const Item* item = AI_GetItemForShootType(shootType, AIL_ent);
    if (item == nullptr) {
        shootType = ST_LEFT;
        item = AI_GetItemForShootType(shootType, AIL_ent);
    }

    /* Check for weapon. */
    if (item == nullptr) {
        lua_pushboolean(L, 0);
        return 1;
    }
    const fireDef_t* fd = item->getFastestFireDef();
    if (fd == nullptr) {
        lua_pushboolean(L, 0);
        return 1;
    }

    int fdTime = G_ActorGetModifiedTimeForFiredef(AIL_ent, fd, false);
    if (tus - fdTime <= 0) {
        lua_pushboolean(L, 0);
        return 1;
    }

    /* Calculate move table. */
    G_MoveCalc(0, actor, actor->pos, tus);
    gi.MoveStore(level.pathingMap);

    /* set borders */
    const int rad = (tus + 1) / TU_MOVE_STRAIGHT;

    pos3_t oldPos;
    vec3_t oldOrigin;
    VectorCopy(actor->pos, oldPos);
    VectorCopy(actor->origin, oldOrigin);

    /* evaluate moving to every possible location in the search area,
     * including combat considerations */
    float bestScore = 0.0f;
    pos3_t to, bestPos;
    VectorSet(bestPos, 0, 0, PATHFINDING_HEIGHT);
    AiAreaSearch searchArea(oldPos, rad);
    while (searchArea.getNext(to)) {
        actor->setOrigin(to);
        const pos_t move = G_ActorMoveLength(actor, level.pathingMap, to, true);
        if (move > tus || move == ROUTING_NOT_REACHABLE)
            continue;
        if (!AI_CheckPosition(actor, actor->pos))
            continue;
        /* Can we see the target? */
        if (!G_IsVisibleForTeam(target->actor, actor->getTeam()) && G_ActorVis(actor, target->actor, true) < ACTOR_VIS_10)
            continue;

        const float dist = VectorDist(actor->origin, target->actor->origin);
        int dummy = NONE;
        const float bestDmg = AIL_GetBestShot(*actor, *target->actor, tus - move, dist, dummy, dummy, dummy);
        if (dummy == NONE)
            continue;

        float score;
        switch (posType) {
        case AILSP_NEAR:
            score = -dist;
            break;
        case AILSP_FAR:
            score = dist;
            break;
        case AILSP_DMG:
            score = bestDmg;
            break;
        case AILSP_FAST:
        default:
            score = -move;
            break;
        }
        if (score > bestScore || bestPos[2] >= PATHFINDING_HEIGHT) {
            VectorCopy(to, bestPos);
            bestScore = score;
        }
    }

    VectorCopy(oldPos, actor->pos);
    VectorCopy(oldOrigin, actor->origin);

    /* No position found in range. */
    if (bestPos[2] >= PATHFINDING_HEIGHT) {
        lua_pushboolean(L, 0);
        return 1;
    }

    /* Return the spot. */
    lua_pushpos3(L, &bestPos);
    return 1;
}

static int AIL_positionhide (lua_State* L)
{
    int hidingTeam = AI_GetHidingTeam(AIL_ent);

    /* parse parameter */
    if (lua_gettop(L)) {
        if (lua_isstring(L, 1)) {
            const char* s = lua_tostring(L, 1);
            bool invTeam = false;
            if (s[0] == '-' || s[0] == '~') {
                invTeam = true;
                ++s;
            }
            const int team = AIL_toTeamInt(s, 1);
            if (team == TEAM_ALL)
                AIL_invalidparameter(1);
            else if (invTeam)
                hidingTeam = -team;
            else
                hidingTeam = team;
        } else {
            AIL_invalidparameter(1);
        }
    }

    int tus = AIL_ent->getUsableTUs();
    /* parse parameter */
    if (lua_gettop(L) > 1) {
        if (lua_isnumber(L, 2)) {
            tus = std::min(static_cast<int>(lua_tonumber(L, 2)), tus);
        } else {
            AIL_invalidparameter(2);
        }
    }

    pos3_t save;
    VectorCopy(AIL_ent->pos, save);

    if (AI_FindHidingLocation(hidingTeam, AIL_ent, AIL_ent->pos, tus)) {
        /* Return the spot. */
        lua_pushpos3(L, &AIL_ent->pos);
    } else {
        lua_pushboolean(L, 0);
    }
    AIL_ent->setOrigin(save);
    return 1;
}

static int AIL_positionherd (lua_State* L)
{
    /* check parameter */
    if (!(lua_gettop(L) && lua_isactor(L, 1))) {
        AIL_invalidparameter(1);
        lua_pushboolean(L, 0);
        return 1;
    }
    const aiActor_t* target = lua_toactor(L, 1);

    int tus = AIL_ent->getUsableTUs();
    /* parse parameter */
    if (lua_gettop(L) > 1) {
        if (lua_isnumber(L, 2)) {
            tus = std::min(static_cast<int>(lua_tonumber(L, 2)), tus);
        } else {
            AIL_invalidparameter(2);
        }
    }

    bool inverse = false;
    if (lua_gettop(L) > 2) {
        if (lua_isboolean(L, 3))
            inverse = lua_toboolean(L, 3);
        else
            AIL_invalidparameter(3);
    }

    pos3_t save;
    VectorCopy(AIL_ent->pos, save);
    if (AI_FindHerdLocation(AIL_ent, AIL_ent->pos, target->actor->origin, tus, inverse)) {
        lua_pushpos3(L, &AIL_ent->pos);
    } else {
        lua_pushboolean(L, 0);
    }
    AIL_ent->setOrigin(save);
    return 1;
}

static int AIL_positionapproach (lua_State* L)
{
    /* check parameter */
    if (!(lua_gettop(L) && lua_ispos3(L, 1))) {
        AIL_invalidparameter(1);
        lua_pushboolean(L, 0);
        return 1;
    }

    const pos3_t* target = lua_topos3(L, 1);
    assert(target != nullptr);

    int tus = AIL_ent->getUsableTUs();
    if (lua_gettop(L) > 1) {
        if (lua_isnumber(L, 2))
            tus = std::min(static_cast<int>(lua_tonumber(L, 2)), tus);
        else
            AIL_invalidparameter(2);
    }

    bool hide = false;
    if (lua_gettop(L) > 2){
        if (lua_isboolean(L, 3))
            hide = lua_toboolean(L, 3);
        else
            AIL_invalidparameter(3);
    }

    /* Find a path to the target actor */
    const int maxTUs = ROUTING_NOT_REACHABLE - 1;
    pos3_t to;
    VectorCopy(*target, to);
    byte crouchingState = AIL_ent->isCrouched() ? 1 : 0;
    if (!G_FindPath(0, AIL_ent, AIL_ent->pos, to, crouchingState, maxTUs)) {
        /* Not found */
        lua_pushboolean(L, 0);
        return 1;
    }

    /* Find the farthest we can go with current TUs */
    int dvec;
    while ((dvec = gi.MoveNext(level.pathingMap, to, crouchingState)) != ROUTING_UNREACHABLE) {
        /* Note: here we skip the first position so we don't try to walk into the target */
        PosSubDV(to, crouchingState, dvec);
        if (hide && (G_TestVis(AI_GetHidingTeam(AIL_ent), AIL_ent, VT_PERISHCHK | VT_NOFRUSTUM) & VS_YES))
            continue;
        if (!AI_CheckPosition(AIL_ent, to))
            continue;
        const byte length =  G_ActorMoveLength(AIL_ent, level.pathingMap, to, false);
        if (length <= tus)
            break;
        /* We are going backwards to the origin. */
    }

    if (AIL_ent->isSamePosAs(to))
        lua_pushboolean(L, 0);
    else
        lua_pushpos3(L, &to);
    return 1;
}

static int AIL_missiontargets (lua_State* L)
{

    /* Defaults. */
    int team = TEAM_ALL;
    ailVisType_t vision = AILVT_ALL;
    ailSortCritType_t sortCrit = AILSC_DIST;
    bool invTeam = false;

    /* Handle parameters. */
    if ((lua_gettop(L) > 0)) {
        /* Get what to "see" with. */
        vision = AIL_toVisInt(L, 1);

        /* We now check for different teams. */
        if ((lua_gettop(L) > 1)) {
            if (lua_isstring(L, 2)) {
                const char* s = lua_tostring(L, 2);
                if (s[0] == '-' || s[0] == '~') {
                    invTeam = true;
                    ++s;
                }
                team = AIL_toTeamInt(s, 2);
                /* Trying to see no one? */
                if (team == TEAM_ALL && invTeam)
                    AIL_invalidparameter(2);
            } else
                AIL_invalidparameter(2);
        }

        /* Sorting criteria */
        if ((lua_gettop(L) > 2))
            sortCrit = AIL_toDistInt(L, 3);
    }

    int n = 0;
    AilSortTable<Edict*> sortTable[MAX_EDICTS];
    /* Get visible things. */
    const int visDist = G_VisCheckDist(AIL_ent);
    Edict* mission = nullptr;
    while ((mission = G_EdictsGetNextInUse(mission))) {
        if (mission->type != ET_MISSION)
            continue;
        const float distance = VectorDistSqr(AIL_ent->pos, mission->pos);
        /* Check for team match if needed. */
        if ((team == TEAM_ALL || (mission->getTeam() == team ? !invTeam : invTeam))
                && (vision == AILVT_ALL
                || (vision == AILVT_SIGHT && !G_TestLineWithEnts(AIL_ent->origin, mission->origin))
                || (vision == AILVT_DIST && distance <= visDist * visDist))) {
            switch (sortCrit) {
            case AILSC_PATH:
            {
                pos_t move = ROUTING_NOT_REACHABLE;
                if (G_FindPath(0, AIL_ent, AIL_ent->pos, mission->pos, false, ROUTING_NOT_REACHABLE - 1))
                    move = gi.MoveLength(level.pathingMap, mission->pos, 0, false);
                sortTable[n].sortLookup = move;
            }
                break;
            case AILSC_DIST:
            default:
                sortTable[n].sortLookup = VectorDistSqr(AIL_ent->pos, mission->pos);
                break;
            }
            sortTable[n++].data = mission;
        }
    }

    /* Sort by given criterion - lesser first. */
    std::sort(sortTable, sortTable + n);

    /* Now save it in a Lua table. */
    lua_newtable(L);
    for (int i = 0; i < n; i++) {
        lua_pushnumber(L, i + 1); /* index, starts with 1 */
        lua_pushpos3(L, &sortTable[i].data->pos); /* value */
        lua_rawset(L, -3); /* store the value in the table */
    }
    return 1; /* Returns the table of positions. */
}

static int AIL_waypoints (lua_State* L)
{
    const float minEnemyDist = 160.0f;
    /* Min distance to waypoint */
    float minDist = 800.0f;
    if (lua_gettop(L) > 0) {
        if (lua_isnumber(L, 1))
            minDist = lua_tonumber(L, 1);
        else
            AIL_invalidparameter(1);
    }

    /* Sorting criteria */
    ailSortCritType_t sortCrit = AILSC_DIST;
    if ((lua_gettop(L) > 1))
        sortCrit = AIL_toDistInt(L, 2);

    int n = 0;
    AilSortTable<Edict*> sortTable[MAX_EDICTS];
    for (Edict* checkPoint = level.ai_waypointList; checkPoint != nullptr; checkPoint = checkPoint->groupChain) {
        if (checkPoint->inuse)
            continue;
        if (checkPoint->getTeam() != AIL_ent->getTeam())
            continue;
        /* Don't walk to enemy ambush */
        Actor* check = nullptr;
        bool ambush = false;
        while ((check = G_EdictsGetNextLivingActorOfTeam(check, TEAM_ALIEN))) {
            const float dist = VectorDist(AIL_ent->origin, check->origin);
            /* @todo add visibility check here? */
            if (dist < minEnemyDist) {
                ambush = true;
                break;
            }
        }
        if (ambush)
            continue;
        switch (sortCrit) {
        case AILSC_PATH:
            {
                pos_t move = ROUTING_NOT_REACHABLE;
                if (G_FindPath(0, AIL_ent, AIL_ent->pos, checkPoint->pos, false, ROUTING_NOT_REACHABLE - 1))
                    move = gi.MoveLength(level.pathingMap, checkPoint->pos, 0, false);
                if (move < minDist * TU_MOVE_STRAIGHT)
                    continue;
                if (checkPoint->count < AIL_ent->count) {
                    sortTable[n].sortLookup = move;
                    sortTable[++n].data = checkPoint;
                }
            }
            break;
        case AILSC_DIST:
        default:
            {
                const float dist = VectorDist(AIL_ent->origin, checkPoint->origin);
                if (dist < minDist * UNIT_SIZE)
                    continue;
                if (checkPoint->count < AIL_ent->count) {
                    sortTable[n].sortLookup = dist;
                    sortTable[++n].data = checkPoint;
                }
            }
            break;
        }
    }

    /* Sort by distance */
    std::sort(sortTable, sortTable + n);

    /* Now save it in a Lua table. */
    lua_newtable(L);
    for (int i = 0; i < n; i++) {
        lua_pushnumber(L, i + 1); /* index, starts with 1 */
        lua_pushpos3(L, &sortTable[i].data->pos); /* value */
        lua_rawset(L, -3); /* store the value in the table */
    }
    return 1; /* Returns the table of positions. */
}

static int AIL_positionmission (lua_State* L)
{
    /* check parameter */
    if (!(lua_gettop(L) && lua_ispos3(L, 1))) {
        AIL_invalidparameter(1);
        lua_pushboolean(L, 0);
        return 1;
    }
    const pos3_t* target = lua_topos3(L, 1);
    int tus = AIL_ent->getUsableTUs();
    if (lua_gettop(L) > 1) {
        if (lua_isnumber(L, 2))
            tus = lua_tonumber(L, 2);
        else
            AIL_invalidparameter(2);
    }
    G_MoveCalc(0, AIL_ent, AIL_ent->pos, tus);
    gi.MoveStore(level.pathingMap);

    pos3_t oldPos;
    VectorCopy(AIL_ent->pos, oldPos);
    int radius = 3;
    const Edict* const mission = G_GetEdictFromPos(*target, ET_MISSION);
    if (mission)
        radius = mission->radius;
    if (AI_FindMissionLocation(AIL_ent, *target, tus, radius))
        lua_pushpos3(L, &AIL_ent->pos);
    else
        lua_pushboolean(L, 0);

    AIL_ent->setOrigin(oldPos);
    return 1;
}

static int AIL_positionwander (lua_State* L)
{
    /* Calculate move table. */
    G_MoveCalc(0, AIL_ent, AIL_ent->pos, AIL_ent->getUsableTUs());
    gi.MoveStore(level.pathingMap);

    /* Set defaults */
    int radius = (AIL_ent->getUsableTUs() + 1) / TU_MOVE_STRAIGHT;
    pos3_t center;
    VectorCopy(AIL_ent->pos, center);
    int method = AILPW_RAND;
    int tus = AIL_ent->getUsableTUs();

    /* Check parameters */
    if (lua_gettop(L) > 0)
            method = AIL_toWanderPInt(L, 1);
    if (lua_gettop(L) > 1) {
        if (lua_isnumber(L, 2))
            radius = lua_tonumber(L, 2);
        else
            AIL_invalidparameter(2);
    }
    if (lua_gettop(L) > 2) {
        if (lua_ispos3(L, 3))
            VectorCopy(*lua_topos3(L, 3), center);
        else
            AIL_invalidparameter(3);
    }

    if (lua_gettop(L) > 3) {
        if (lua_isnumber(L, 4))
            tus = std::min(static_cast<int>(lua_tonumber(L, 4)), tus);
        else
            AIL_invalidparameter(4);
    }

    vec3_t d;
    if (method > 0)
        VectorSubtract(AIL_ent->pos, center, d);
    const int cDir = method > 0 ? (VectorEmpty(d) ? AIL_ent->dir : AngleToDir(static_cast<int>(atan2(d[1], d[0]) * todeg))) : NONE;
    float bestScore = 0;
    pos3_t bestPos = {0, 0, PATHFINDING_HEIGHT};
    pos3_t pos;
    AiAreaSearch searchArea(center, radius);
    while (searchArea.getNext(pos)) {
        const pos_t move = G_ActorMoveLength(AIL_ent, level.pathingMap, pos, true);
        if (move >= ROUTING_NOT_REACHABLE || move > tus)
            continue;
        if (!AI_CheckPosition(AIL_ent, pos))
            continue;
        float score = 0.0f;
        switch (method) {
        case AILPW_RAND:
            score = rand();
            break;
        case AILPW_CW:
        case AILPW_CCW: {
            score = VectorDistSqr(center, pos);
            VectorSubtract(pos, center, d);
            int dir = AngleToDir(static_cast<int>(atan2(d[1], d[0]) * todeg));
            if (!(method == AILPW_CW && dir == dvright[cDir]) && !(method == AILPW_CCW && dir == dvleft[cDir]))
                for (int n = 1; n < 8; ++n) {
                    dir = method == 1 ? dvleft[dir] : dvright[dir];
                    score /= pow(n * 2.0f, 2);
                    if ((method == 1 && dir == dvright[cDir]) || (method == 2 && dir == dvleft[cDir]))
                        break;
                }
        }
            break;
        }
        if (score > bestScore) {
            bestScore = score;
            VectorCopy(pos, bestPos);
        }
    }

    if (bestPos[2] >= PATHFINDING_HEIGHT) {
        lua_pushboolean(L, 0);
        return 1;
    }
    lua_pushpos3(L, &bestPos);
    return 1;
}

static int AIL_findweapons (lua_State* L)
{
    bool full = false;
    if (lua_gettop(L) > 0) {
        if (lua_isboolean(L, 1))
            full = lua_toboolean(L, 1);
        else
            AIL_invalidparameter(1);
    }

    AilSortTable<Edict*> sortTable[MAX_EDICTS];
    int n = 0;
    Edict* check = nullptr;
    while ((check = G_EdictsGetNextInUse(check))) {
        if (check->type != ET_ITEM)
            continue;
        if(!AI_CheckPosition(AIL_ent, check->pos))
            continue;
        if (!G_FindPath(0, AIL_ent, AIL_ent->pos, check->pos, AIL_ent->isCrouched(), ROUTING_NOT_REACHABLE - 1))
            continue;
        const pos_t move = G_ActorMoveLength(AIL_ent, level.pathingMap, check->pos, false);
        if (full || move <= AIL_ent->getUsableTUs() - INVDEF(CID_FLOOR)->out - INVDEF(CID_RIGHT)->in) {
            for (const Item* item = check->getFloor(); item; item = item->getNext()) {
                if (item->isWeapon() && (item->getAmmoLeft() > 0 || item->def()->ammo <= 0)) {
                            sortTable[n].data = check;
                            sortTable[n++].sortLookup = move;
                    break;
                }
            }
        }
    }

    /* Sort by distance */
    std::sort(sortTable, sortTable + n);

    /* Now save it in a Lua table. */
    lua_newtable(L);
    for (int i = 0; i < n; i++) {
        lua_pushnumber(L, i + 1); /* index, starts with 1 */
        lua_pushpos3(L, &sortTable[i].data->pos); /* value */
        lua_rawset(L, -3); /* store the value in the table */
    }
    return 1; /* Returns the table of positions. */
}

static int AIL_isfighter (lua_State* L)
{
    const bool result = AIL_ent->chr.teamDef->weapons || AIL_ent->chr.teamDef->onlyWeapon;
    lua_pushboolean(L, result);
    return 1;
}

static int AIL_setwaypoint (lua_State* L)
{
    /* No waypoint, reset the count value to restart the search */
    if (lua_gettop(L) < 1 || lua_isnil(L, 1)) {
        AIL_ent->count = 100;
        lua_pushboolean(L, 1);
    } else if (lua_ispos3(L, 1)){
        pos3_t pos;
        Edict* waypoint = G_GetEdictFromPos(pos, ET_CIVILIANTARGET);
        if (waypoint != nullptr) {
            AIL_ent->count = waypoint->count;
            lua_pushboolean(L, 1);
        } else
            lua_pushboolean(L, 0);
    } else
        lua_pushboolean(L, 0);

    return 1;
}

static int AIL_difficulty (lua_State* L)
{
    lua_pushnumber(L, g_difficulty->value);
    return 1;
}

static int AIL_positionflee (lua_State* L)
{
    int tus = AIL_ent->getUsableTUs();
    if (lua_gettop(L)) {
        if (lua_isnumber(L, 1))
            tus = std::min(static_cast<int>(lua_tonumber(L, 1)), tus);
        else
            AIL_invalidparameter(1);
    }

    /* Calculate move table. */
    G_MoveCalc(0, AIL_ent, AIL_ent->pos, AIL_ent->getUsableTUs());
    pos3_t oldPos;
    VectorCopy(AIL_ent->pos, oldPos);

    const int radius = (tus + 1) / TU_MOVE_STRAIGHT;
    float bestScore = -1;
    pos3_t bestPos = {0, 0, PATHFINDING_HEIGHT};
    AiAreaSearch searchArea(AIL_ent->pos, radius);
    while (searchArea.getNext(AIL_ent->pos)) {
        const pos_t move = G_ActorMoveLength(AIL_ent, level.pathingMap, AIL_ent->pos, false);
        if (move >= ROUTING_NOT_REACHABLE || move > tus)
            continue;
        if (!AI_CheckPosition(AIL_ent, AIL_ent->pos))
            continue;
        float minDistFoe = -1.0f, minDistFriend = -1.0f;
        Actor* check = nullptr;
        while ((check = G_EdictsGetNextLivingActor(check))) {
            const float dist = VectorDist(AIL_ent->origin, check->origin);
            if (check->isSameTeamAs(AIL_ent)) {
                if (dist < minDistFriend || minDistFriend < 0.0f)
                    minDistFriend = dist;
            } else if (AI_IsHostile(AIL_ent, check) || AIL_ent->isPanicked()) {
                if (dist < minDistFoe || minDistFoe < 0.0f)
                    minDistFoe = dist;
            }
        }
        float score = minDistFoe - (minDistFriend / GRID_WIDTH);
        /* Try to hide */
        AIL_ent->calcOrigin();
        if (G_TestVis(AI_GetHidingTeam(AIL_ent), AIL_ent, VT_PERISHCHK | VT_NOFRUSTUM) & VS_YES)
            score /= UNIT_SIZE;
        if (score > bestScore) {
            bestScore = score;
            VectorCopy(AIL_ent->pos, bestPos);
        }
    }
    AIL_ent->setOrigin(oldPos);

    if (bestPos[2] == PATHFINDING_HEIGHT) {
        lua_pushboolean(L, 0);
    } else {
        lua_pushpos3(L, &bestPos);
    }

    return 1;
}

static int AIL_weapontype (lua_State* L)
{
    const Item* right = AIL_ent->getRightHandItem();
    const Item* left = AIL_ent->getLeftHandItem();

    lua_pushstring(L, right ? right->def()->type : "none");
    lua_pushstring(L, left ? left->def()->type : "none");

    return 2;
}

static int AIL_actor (lua_State* L)
{
    aiActor_t actor = {AIL_ent};
    lua_pushactor(L, &actor);
    return 1;
}
static int AIL_tusforshooting (lua_State* L)
{
    int bestTUs = 256;
    const Item* weapon = AIL_ent->getRightHandItem();
    if (weapon) {
        const fireDef_t* fd = weapon->getFastestFireDef();
        if (fd)
            bestTUs = fd->time;
    }
    weapon = AIL_ent->getLeftHandItem();
    if (weapon) {
        const fireDef_t* fd = weapon->getFastestFireDef();
        if (fd) {
            const int tus = weapon->getFastestFireDef()->time;
            if (tus < bestTUs)
                bestTUs = tus;
        }
    }

    lua_pushnumber(L, bestTUs);
    return 1;
}

static int AIL_class (lua_State* L)
{
    lua_pushstring(L, AIL_ent->AI.subtype);
    return 1;
}

static int AIL_hideneeded (lua_State* L)
{
    lua_pushboolean(L, AI_HideNeeded(AIL_ent));
    return 1;
}

void AIL_ActorThink (Player& player, Actor* actor)
{
    /* Set the global player and edict */
    AIL_ent = actor;
    AIL_player = &player;

    /* Try to run the function. */
    lua_getglobal(ailState, actor->AI.type);
    if (lua_istable(ailState, -1)) {
        lua_getfield(ailState, -1, "think");
        if (lua_pcall(ailState, 0, 0, 0)) { /* error has occured */
            gi.DPrintf("Error while running Lua: %s\n",
                lua_isstring(ailState, -1) ? lua_tostring(ailState, -1) : "Unknown Error");
        }
    } else {
        gi.DPrintf("Error while running Lua: AI for %s not found!\n", actor->AI.type);
    }

    /* Cleanup */
    AIL_ent = nullptr;
    AIL_player = nullptr;
}

static const char* AIL_GetAIType (const int team)
{
    const char* type;
    switch (team) {
    case TEAM_ALIEN:
        type = "alien";
        break;
    case TEAM_CIVILIAN:
        type = "civilian";
        break;
    case TEAM_PHALANX:
    default:    /* Default to "soldier" AI for multiplayer teams */
        type = "soldier";
        break;
    }
    return type;
}

bool AIL_TeamThink (Player& player)
{
    /* Set the global player */
    AIL_player = &player;
    AIL_ent = nullptr;

    bool thinkAgain = false;
    /* Try to run the function. */
    lua_getglobal(ailState, AIL_GetAIType(player.getTeam()));
    if (lua_istable(ailState, -1)) {
        lua_getfield(ailState, -1, "team_think");
        if (lua_pcall(ailState, 0, 1, 0)) { /* error has occured */
            gi.DPrintf("Error while running Lua: %s\n",
                lua_isstring(ailState, -1) ? lua_tostring(ailState, -1) : "Unknown Error");
        } else
            thinkAgain = lua_toboolean(ailState, -1);
    } else {
        gi.DPrintf("Error while running Lua: AI for %s not found!\n", AIL_toTeamString(player.getTeam()));
    }

    /* Cleanup */
    AIL_player = nullptr;
    AIL_ent = nullptr;
    return thinkAgain;
}

static lua_State* AIL_InitLua () {
    /* Create the Lua state */
    lua_State* newState = luaL_newstate();

    /* Register metatables. */
    actorL_register(newState);
    pos3L_register(newState);

    /* Register libraries. */
    luaL_register(newState, AI_METATABLE, AIL_methods);

    return newState;
}
int AIL_InitActor (Actor* actor)
{
    /* Prepare the AI */
    AI_t* AI = &actor->AI;
    Q_strncpyz(AI->type, AIL_GetAIType(actor->getTeam()), sizeof(AI->type));
    Q_strncpyz(AI->subtype, actor->chr.teamDef->id, sizeof(AI->subtype));

    /* Create the a new Lua state if needed */
    if (ailState == nullptr)
        ailState = AIL_InitLua();

    if (ailState == nullptr) {
        gi.DPrintf("Unable to create Lua state.\n");
        return -1;
    }

    /* Load the AI if needed */
    lua_getglobal(ailState, AI->type);
    if (!lua_istable(ailState, -1)) {
        char path[MAX_VAR];
        Com_sprintf(path, sizeof(path), "ai/%s.lua", AI->type);
        char* fbuf;
        const int size = gi.FS_LoadFile(path, (byte**) &fbuf);
        if (size == 0) {
            gi.DPrintf("Unable to load Lua file '%s'.\n", path);
            return -1;
        }
        if (luaL_dobuffer(ailState, fbuf, size, path)) {
            gi.DPrintf("Unable to parse Lua file '%s'\n", path);
            gi.DPrintf("%s\n", lua_isstring(ailState, -1) ? lua_tostring(ailState, -1) : "Unknown Error");
            gi.FS_FreeFile(fbuf);
            return -1;
        }
        lua_setglobal(ailState, AI->type);
        gi.FS_FreeFile(fbuf);
    } else {
        lua_pop(ailState, 1);
    }

    return 0;
}

void AIL_Init (void)
{
    gi.RegisterConstInt("luaaiteam::phalanx", TEAM_PHALANX);
    gi.RegisterConstInt("luaaiteam::civilian", TEAM_CIVILIAN);
    gi.RegisterConstInt("luaaiteam::alien", TEAM_ALIEN);
    gi.RegisterConstInt("luaaiteam::all", TEAM_ALL);

    gi.RegisterConstInt("luaaivis::all", AILVT_ALL);
    gi.RegisterConstInt("luaaivis::sight", AILVT_SIGHT);
    gi.RegisterConstInt("luaaivis::team", AILVT_TEAM);
    gi.RegisterConstInt("luaaivis::extra", AILVT_DIST);

    gi.RegisterConstInt("luaaisort::dist", AILSC_DIST);
    gi.RegisterConstInt("luaaisort::path", AILSC_PATH);
    gi.RegisterConstInt("luaaisort::HP", AILSC_HP);

    gi.RegisterConstInt("luaaidist::dist", AILSC_DIST);
    gi.RegisterConstInt("luaaidist::path", AILSC_PATH);

    gi.RegisterConstInt("luaaishot::fastest", AILSP_FAST);
    gi.RegisterConstInt("luaaishot::nearest", AILSP_NEAR);
    gi.RegisterConstInt("luaaishot::farthest", AILSP_FAR);
    gi.RegisterConstInt("luaaishot::best_dam", AILSP_DMG);

    gi.RegisterConstInt("luaaiwander::rand", AILPW_RAND);
    gi.RegisterConstInt("luaaiwander::CW", AILPW_CW);
    gi.RegisterConstInt("luaaiwander::CCW", AILPW_CCW);

    ailState = nullptr;
}

void AIL_Shutdown (void)
{
    gi.UnregisterConstVariable("luaaiteam::phalanx");
    gi.UnregisterConstVariable("luaaiteam::civilian");
    gi.UnregisterConstVariable("luaaiteam::alien");
    gi.UnregisterConstVariable("luaaiteam::all");

    gi.UnregisterConstVariable("luaaivis::all");
    gi.UnregisterConstVariable("luaaivis::sight");
    gi.UnregisterConstVariable("luaaivis::team");
    gi.UnregisterConstVariable("luaaivis::extra");

    gi.UnregisterConstVariable("luaaisort::dist");
    gi.UnregisterConstVariable("luaaisort::path");
    gi.UnregisterConstVariable("luaaisort::HP");

    gi.UnregisterConstVariable("luaaidist::dist");
    gi.UnregisterConstVariable("luaaidist::path");

    gi.UnregisterConstVariable("luaaishot::fastest");
    gi.UnregisterConstVariable("luaaishot::nearest");
    gi.UnregisterConstVariable("luaaishot::farthest");
    gi.UnregisterConstVariable("luaaishot::best_dam");

    gi.UnregisterConstVariable("luaaiwander::rand");
    gi.UnregisterConstVariable("luaaiwander::CW");
    gi.UnregisterConstVariable("luaaiwander::CCW");
}

void AIL_Cleanup (void)
{
    lua_close(ailState);
    ailState = nullptr;
}