cp_ufo.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 "../../cl_shared.h"
#include "cp_campaign.h"
#include "cp_geoscape.h"
#include "cp_ufo.h"
#include "cp_aircraft.h"
#include "cp_mapfightequip.h"
#include "cp_missions.h"
#include "cp_ufo_callbacks.h"

static const float MAX_DETECTING_RANGE = 25.0f; 
aircraft_t* UFO_GetNext (aircraft_t* lastUFO)
{
    aircraft_t* endOfUFOs = &ccs.ufos[ccs.numUFOs];
    aircraft_t* ufo;

    if (!ccs.numUFOs)
        return nullptr;

    if (!lastUFO)
        return ccs.ufos;
    assert(lastUFO >= ccs.ufos);
    assert(lastUFO < endOfUFOs);

    ufo = lastUFO;

    ufo++;
    if (ufo >= endOfUFOs)
        return nullptr;
    else
        return ufo;
}

aircraft_t* UFO_GetNextOnGeoscape (aircraft_t* lastUFO)
{
    aircraft_t* ufo = lastUFO;
    while ((ufo = UFO_GetNext(ufo)) != nullptr) {
        if (UFO_IsUFOSeenOnGeoscape(ufo)
#ifdef DEBUG
        || cgi->Cvar_GetInteger("debug_showufos")
#endif
        )
            return ufo;
    }

    return nullptr;
}

aircraft_t* UFO_GetByIDX (const int idx)
{
    assert(idx >= 0 && idx < MAX_UFOONGEOSCAPE);
    return &ccs.ufos[idx];
}

const technology_t* UFO_GetTechnologyFromType (const ufoType_t type)
{
    const char* id = cgi->Com_UFOTypeToShortName(type);
    const technology_t* tech = RS_GetTechByProvided(id);
    return tech;
}

const aircraft_t* UFO_GetByType (const ufoType_t type)
{
    for (int i = 0; i < ccs.numAircraftTemplates; i++) {
        aircraft_t* ufo = &ccs.aircraftTemplates[i];
        if (ufo->getUfoType() == type)
            return ufo;
    }

    cgi->Com_Error(ERR_DROP, "No ufo with type %i found", type);
}

bool UFO_ShouldAppearOnGeoscape (const ufoType_t type)
{
    const aircraft_t* ufo = UFO_GetByType(type);

    return ufo->ufoInterestOnGeoscape <= ccs.overallInterest;
}

bool UFO_CanDoMission (const ufoType_t uType, const char* mType)
{
    const aircraft_t* ufo = UFO_GetByType(uType);
    if (cgi->LIST_ContainsString(ufo->missionTypes, mType))
        return true;

    return false;
}

int UFO_GetAvailableUFOsForMission (const interestCategory_t missionType, ufoType_t* ufoTypes, bool checkInterest)
{
    int num = 0;

    const short ufoIdsNum = cgi->Com_GetUFOIdsNum();
    for (int i = 0; i < ufoIdsNum; i++) {
        ufoType_t uType = i;
        switch (missionType) {
            case INTERESTCATEGORY_RECON:
                if (!UFO_CanDoMission(uType, "recon"))
                    continue;
                break;
            case INTERESTCATEGORY_BASE_ATTACK:
                if (!UFO_CanDoMission(uType, "baseattack"))
                    continue;
                break;
            case INTERESTCATEGORY_SUPPLY:
                if (!UFO_CanDoMission(uType, "supply"))
                    continue;
                break;
            case INTERESTCATEGORY_HARVEST:
                if (!UFO_CanDoMission(uType, "harvest"))
                    continue;
                break;
            case INTERESTCATEGORY_XVI:
                if (!UFO_CanDoMission(uType, "xvi"))
                    continue;
                break;
            case INTERESTCATEGORY_TERROR_ATTACK:
                if (!UFO_CanDoMission(uType, "terror"))
                    continue;
                break;
            case INTERESTCATEGORY_INTERCEPT:
                if (!UFO_CanDoMission(uType, "intercept"))
                    continue;
                break;
            case INTERESTCATEGORY_INTERCEPTBOMBING:
                if (!UFO_CanDoMission(uType, "interceptbombing"))
                    continue;
                break;
            case INTERESTCATEGORY_BUILDING:
                if (!UFO_CanDoMission(uType, "building"))
                    continue;
                break;
            case INTERESTCATEGORY_SUBVERT:
                if (!UFO_CanDoMission(uType, "subvert"))
                    continue;
                break;
            default:
                continue;
        }
        if (!checkInterest || UFO_ShouldAppearOnGeoscape(uType))
            ufoTypes[num++] = uType;
    }

    return num;
}

int UFO_GetOneAvailableUFOForMission (const interestCategory_t missionType, bool checkInterest)
{
    ufoType_t ufoTypes[UFO_MAX];
    int numTypes = UFO_GetAvailableUFOsForMission(missionType, ufoTypes, checkInterest);
    return numTypes ? ufoTypes[0] : UFO_NONE;
}

const char* UFO_TypeToName (const ufoType_t type)
{
    const technology_t* tech = UFO_GetTechnologyFromType(type);
    if (tech)
        return _(tech->name);
    cgi->Com_Error(ERR_DROP, "UFO_TypeToName(): Unknown UFO type %i\n", type);
}

const char* UFO_GetName (const aircraft_t* ufocraft)
{
    const technology_t* tech = ufocraft->tech;

    assert(tech);

    if (ufocraft->detectionIdx)
        return va("%s #%i", (RS_IsResearched_ptr(tech)) ? _(ufocraft->name) : _("UFO"), ufocraft->detectionIdx);
    return (RS_IsResearched_ptr(tech)) ? _(ufocraft->name) : _("UFO");
}

void UFO_SetRandomDest (aircraft_t* ufocraft)
{
    vec2_t pos;

    CP_GetRandomPosOnGeoscape(pos, false);

    UFO_SendToDestination(ufocraft, pos);
}

void UFO_SetRandomDestAround (aircraft_t* ufocraft, const vec2_t pos)
{
    vec2_t dest;
    const float spread = 2.0f;
    float rand1, rand2;

    gaussrand(&rand1, &rand2);
    rand1 *= spread;
    rand2 *= spread;

    Vector2Set(dest, pos[0] + rand1, pos[1] + rand2);

    UFO_SendToDestination(ufocraft, dest);
}

static void UFO_SetRandomPos (aircraft_t* ufocraft)
{
    vec2_t pos;

    CP_GetRandomPosOnGeoscape(pos, false);

    Vector2Copy(pos, ufocraft->pos);
}

static int UFO_IsTargetOfBase (const aircraft_t* ufo, const base_t* base)
{
    int i;

    for (i = 0; i < base->numBatteries; i++) {
        if (base->batteries[i].target == ufo)
            return UFO_IS_TARGET_OF_MISSILE;
    }

    for (i = 0; i < base->numLasers; i++) {
        if (base->lasers[i].target == ufo)
            return UFO_IS_TARGET_OF_LASER;
    }

    return UFO_IS_NO_TARGET;
}

static int UFO_IsTargetOfInstallation (const aircraft_t* ufo, const installation_t* installation)
{
    for (int i = 0; i < installation->numBatteries; i++) {
        if (installation->batteries[i].target == ufo)
            return UFO_IS_TARGET_OF_MISSILE;
    }

    return UFO_IS_NO_TARGET;
}

static void UFO_UpdateAlienInterestForOneBase (const aircraft_t* ufo, base_t* base)
{
    float probability;
    float distance;
    const float decreasingDistance = 10.0f; 
    const float decreasingFactor = 5.0f;

    /* ufo can't find base if it's too far */
    distance = GetDistanceOnGlobe(ufo->pos, base->pos);
    if (distance > MAX_DETECTING_RANGE)
        return;

    /* UFO has an increased probability to find a base if it is firing at it */
    switch (UFO_IsTargetOfBase(ufo, base)) {
    case UFO_IS_TARGET_OF_MISSILE:
        probability = 0.01f;
        break;
    case UFO_IS_TARGET_OF_LASER:
        probability = 0.001f;
        break;
    default:
        probability = 0.0001f;
        break;
    }

    /* decrease probability if the ufo is far from base */
    if (distance > decreasingDistance)
        probability /= decreasingFactor;

    /* probability must depend on DETECTION_INTERVAL (in case we change the value) */
    probability *= DETECTION_INTERVAL;

    base->alienInterest += probability;
}

static void UFO_UpdateAlienInterestForOneInstallation (const aircraft_t* ufo, installation_t* installation)
{
    float probability;
    float distance;
    const float decreasingDistance = 10.0f; 
    const float decreasingFactor = 5.0f;

    /* ufo can't find base if it's too far */
    distance = GetDistanceOnGlobe(ufo->pos, installation->pos);
    if (distance > MAX_DETECTING_RANGE)
        return;

    /* UFO has an increased probability to find a base if it is firing at it */
    switch (UFO_IsTargetOfInstallation(ufo, installation)) {
    case UFO_IS_TARGET_OF_MISSILE:
        probability = 0.01f;
        break;
    case UFO_IS_TARGET_OF_LASER:
        probability = 0.001f;
        break;
    default:
        probability = 0.0001f;
        break;
    }

    /* decrease probability if the ufo is far from base */
    if (distance > decreasingDistance)
        probability /= decreasingFactor;

    /* probability must depend on DETECTION_INTERVAL (in case we change the value) */
    probability *= DETECTION_INTERVAL;

    installation->alienInterest += probability;
}

void UFO_UpdateAlienInterestForAllBasesAndInstallations (void)
{
    aircraft_t* ufo;

    ufo = nullptr;
    while ((ufo = UFO_GetNext(ufo)) != nullptr) {
        base_t* base;

        /* landed UFO can't detect any phalanx base or installation */
        if (ufo->landed)
            continue;

        base = nullptr;
        while ((base = B_GetNext(base)) != nullptr)
            UFO_UpdateAlienInterestForOneBase(ufo, base);

        INS_Foreach(installation)
            UFO_UpdateAlienInterestForOneInstallation(ufo, installation);
    }
}

static void UFO_SearchAircraftTarget (const campaign_t* campaign, aircraft_t* ufo, float maxDetectionRange = MAX_DETECTING_RANGE)
{
    float distance = 999999.;

    /* UFO never try to attack a PHALANX aircraft except if they came on earth in that aim */
    if (ufo->mission->stage != STAGE_INTERCEPT) {
        /* Check if UFO is defending itself */
        if (ufo->aircraftTarget)
            UFO_CheckShootBack(campaign, ufo, ufo->aircraftTarget);
        return;
    }

    /* check if the ufo is already attacking an aircraft */
    if (ufo->aircraftTarget) {
        /* check if the target disappeared from geoscape (fled in a base) */
        if (AIR_IsAircraftOnGeoscape(ufo->aircraftTarget))
            AIRFIGHT_ExecuteActions(campaign, ufo, ufo->aircraftTarget);
        else
            ufo->aircraftTarget = nullptr;
        return;
    }

    ufo->status = AIR_TRANSIT;
    AIR_Foreach(phalanxAircraft) {
        /* check that aircraft is flying */
        if (AIR_IsAircraftOnGeoscape(phalanxAircraft)) {
            /* get the distance from ufo to aircraft */
            const float dist = GetDistanceOnGlobe(ufo->pos, phalanxAircraft->pos);
            /* check out of reach */
            if (dist > maxDetectionRange)
                continue;
            /* choose the nearest target */
            if (dist < distance) {
                distance = dist;
                if (UFO_SendPursuingAircraft(ufo, phalanxAircraft) && UFO_IsUFOSeenOnGeoscape(ufo)) {
                    /* stop time and notify */
                    MSO_CheckAddNewMessage(NT_UFO_ATTACKING, _("Notice"), va(_("A UFO is flying toward %s"), phalanxAircraft->name));
                    return;
                }
            }
        }
    }

    /* if this ufo is a leader, it does not try to search another one */
    if (ufo->leader)
        return;
    aircraft_t* otherUFO = nullptr;
    const float polarCoordinatesOffset = 1.0f;
    while ((otherUFO = UFO_GetNextOnGeoscape(otherUFO)) != nullptr) {
        if (otherUFO == ufo)
            continue;
        if (otherUFO->leader) {
            vec2_t dest;
            AIR_GetDestinationWhilePursuing(ufo, otherUFO, dest);
            dest[0] += polarCoordinatesOffset;
            dest[1] += polarCoordinatesOffset;
            GEO_CalcLine(ufo->pos, dest, &ufo->route);
            ufo->time = 0;
            ufo->point = 0;
            break;
        }
    }
}

bool UFO_SendPursuingAircraft (aircraft_t* ufo, aircraft_t* aircraft)
{
    assert(ufo);
    assert(aircraft);

    /* check whether the ufo can shoot the aircraft - if not, don't try it even */
    const int slotIdx = AIRFIGHT_ChooseWeapon(ufo->weapons, ufo->maxWeapons, ufo->pos, aircraft->pos);
    if (slotIdx == AIRFIGHT_WEAPON_CAN_NEVER_SHOOT) {
        /* no ammo left: stop attack */
        ufo->status = AIR_TRANSIT;
        return false;
    }

    vec2_t dest;
    AIR_GetDestinationWhilePursuing(ufo, aircraft, dest);
    GEO_CalcLine(ufo->pos, dest, &ufo->route);
    ufo->status = AIR_UFO;
    ufo->time = 0;
    ufo->point = 0;
    ufo->aircraftTarget = aircraft;

    return true;
}

void UFO_SendToDestination (aircraft_t* ufo, const vec2_t dest)
{
    assert(ufo);

    GEO_CalcLine(ufo->pos, dest, &ufo->route);
    ufo->status = AIR_TRANSIT;
    ufo->time = 0;
    ufo->point = 0;
}

void UFO_CheckShootBack (const campaign_t* campaign, aircraft_t* ufo, aircraft_t* phalanxAircraft)
{
    /* check if the ufo is already attacking an aircraft */
    if (ufo->aircraftTarget) {
        /* check if the target flee in a base */
        if (AIR_IsAircraftOnGeoscape(ufo->aircraftTarget))
            AIRFIGHT_ExecuteActions(campaign, ufo, ufo->aircraftTarget);
        else {
            ufo->aircraftTarget = nullptr;
            CP_UFOProceedMission(campaign, ufo);
        }
    } else {
        /* check that aircraft is flying */
        if (AIR_IsAircraftOnGeoscape(phalanxAircraft))
            UFO_SendPursuingAircraft(ufo, phalanxAircraft);
    }
}

void UFO_CampaignRunUFOs (const campaign_t* campaign, int deltaTime)
{
    /* now the ufos are flying around, too - cycle backward - ufo might be destroyed */
    for (int ufoIdx = ccs.numUFOs - 1; ufoIdx >= 0; ufoIdx--) {
        aircraft_t* ufo = UFO_GetByIDX(ufoIdx);
        /* don't run a landed ufo */
        if (ufo->landed)
            continue;

        /* Every UFO on geoscape should have a mission assigned */
        assert(ufo->mission);

        /* reached target and not following a phalanx aircraft? then we need a new destination */
        if (AIR_AircraftMakeMove(deltaTime, ufo) && ufo->status != AIR_UFO) {
            const vec2_t& end = ufo->route.point[ufo->route.numPoints - 1];
            Vector2Copy(end, ufo->pos);
            GEO_CheckPositionBoundaries(ufo->pos);
            if (ufo->mission->stage == STAGE_INTERCEPT && ufo->mission->data.aircraft) {
                /* Attacking an installation: fly over this installation */
                UFO_SetRandomDestAround(ufo, ufo->mission->pos);
            } else
                UFO_SetRandomDest(ufo);
            if (CP_CheckNextStageDestination(campaign, ufo))
                /* UFO has been removed from game */
                continue;
            /* UFO was destroyed (maybe because the mission was removed) */
            if (ufoIdx == ccs.numUFOs)
                continue;
        }

        /* Search the next target? */
        UFO_SearchAircraftTarget(campaign, ufo);

        /* antimatter tanks */
        if (ufo->fuel <= 0)
            ufo->fuel = ufo->stats[AIR_STATS_FUELSIZE];

        /* Update delay to launch next projectile */
        for (int k = 0; k < ufo->maxWeapons; k++) {
            aircraftSlot_t* slot = &ufo->weapons[k];
            if (slot->delayNextShot > 0)
                slot->delayNextShot -= deltaTime;
        }
    }
}

#ifdef DEBUG

static void UFO_DestroyUFOs_f (void)
{
    aircraft_t* ufo;
    campaign_t* campaign = ccs.curCampaign;

    for (ufo = ccs.ufos; ufo < ccs.ufos + ccs.numUFOs; ufo++) {
        AIRFIGHT_ActionsAfterAirfight(campaign, nullptr, ufo, true);
    }
}

static void UFO_ListOnGeoscape_f (void)
{
    cgi->Com_Printf("There are %i UFOs in game\n", ccs.numUFOs);
    for (aircraft_t* ufo = ccs.ufos; ufo < ccs.ufos + ccs.numUFOs; ufo++) {
        cgi->Com_Printf("..%s (%s) - status: %i - pos: %.0f:%0.f\n", ufo->name, ufo->id, ufo->status, ufo->pos[0], ufo->pos[1]);
        cgi->Com_Printf("...route length: %i (current: %i), time: %i, distance: %.2f, speed: %i\n",
                ufo->route.numPoints, ufo->point, ufo->time, ufo->route.distance, ufo->stats[AIR_STATS_SPEED]);
        cgi->Com_Printf("...linked to mission '%s'\n", ufo->mission ? ufo->mission->id : "no mission");
        cgi->Com_Printf("... UFO is %s and %s\n", ufo->landed ? "landed" : "flying", ufo->detected ? "detected" : "undetected");
        cgi->Com_Printf("... damage: %i\n", ufo->damage);
        cgi->Com_Printf("...%i weapon slots: ", ufo->maxWeapons);
        for (int k = 0; k < ufo->maxWeapons; k++) {
            aircraftSlot_t const* const w = &ufo->weapons[k];
            if (w->item) {
                char const* const state = w->ammo && w->ammoLeft > 0 ?
                "(loaded)" : "(unloaded)";
                cgi->Com_Printf("%s %s / ", w->item->id, state);
            } else
            cgi->Com_Printf("empty / ");
        }
        cgi->Com_Printf("\n");
    }
}
#endif

const aircraft_t* UFO_GetTemplate (ufoType_t ufoType)
{
    int newUFONum;

    for (newUFONum = 0; newUFONum < ccs.numAircraftTemplates; newUFONum++) {
        const aircraft_t* tpl = &ccs.aircraftTemplates[newUFONum];
        if (AIR_IsUFO(tpl) && ufoType == tpl->getUfoType())
            break;
    }

    /* not found */
    if (newUFONum == ccs.numAircraftTemplates)
        return nullptr;

    return &ccs.aircraftTemplates[newUFONum];
}

static const aircraft_t* UFO_GetTemplateForGeoscape (ufoType_t ufoType)
{
    int newUFONum;

    for (newUFONum = 0; newUFONum < ccs.numAircraftTemplates; newUFONum++) {
        const aircraft_t* tpl = &ccs.aircraftTemplates[newUFONum];
        if (AIR_IsUFO(tpl) && ufoType == tpl->getUfoType() && !tpl->notOnGeoscape)
            break;
    }

    /* not found */
    if (newUFONum == ccs.numAircraftTemplates)
        return nullptr;

    return &ccs.aircraftTemplates[newUFONum];
}

aircraft_t* UFO_CreateFromTemplate (const aircraft_t* ufoTemplate)
{
    aircraft_t* ufo;

    if (ufoTemplate == nullptr)
        return nullptr;

    /* check max amount */
    if (ccs.numUFOs >= MAX_UFOONGEOSCAPE)
        return nullptr;

    /* must be an ufo */
    assert(AIR_IsUFO(ufoTemplate));

    /* get a new free slot */
    ufo = UFO_GetByIDX(ccs.numUFOs);
    /* copy the data */
    *ufo = *ufoTemplate;
    /* assign an unique index */
    ufo->idx = ccs.numUFOs++;

    return ufo;
}

aircraft_t* UFO_AddToGeoscape (ufoType_t ufoType, const vec2_t destination, mission_t* mission)
{
    aircraft_t* ufo;
    const aircraft_t* ufoTemplate;

    ufoTemplate = UFO_GetTemplateForGeoscape(ufoType);
    if (ufoTemplate == nullptr)
        return nullptr;

    /* Create ufo */
    ufo = UFO_CreateFromTemplate(ufoTemplate);
    if (ufo == nullptr)
        return nullptr;

    /* Update Stats of UFO */
    AII_UpdateAircraftStats(ufo);
    /* Give it HP */
    ufo->damage = ufo->stats[AIR_STATS_DAMAGE];
    /* Check for 0 damage which cause invulerable UFOs */
    assert(ufo->damage);

    /* Every ufo on geoscape needs a mission assigned */
    assert(mission);

    /* Initialise ufo data */
    UFO_SetRandomPos(ufo);
    AII_ReloadAircraftWeapons(ufo); /* Load its weapons */
    ufo->landed = false;
    ufo->detected = false; /* Not visible in radars (just for now) */
    ufo->mission = mission;
    if (destination)
        UFO_SendToDestination(ufo, destination);
    else
        UFO_SetRandomDest(ufo); /* Random destination */

    return ufo;
}

void UFO_RemoveFromGeoscape (aircraft_t* ufo)
{
    /* Remove ufo from ufos list */
    const ptrdiff_t num = (ptrdiff_t) (ufo - ccs.ufos);

    cgi->Com_DPrintf(DEBUG_CLIENT, "Remove ufo from geoscape: '%s'\n", ufo->id);

    REMOVE_ELEM_ADJUST_IDX(ccs.ufos, num, ccs.numUFOs);
}

#ifdef DEBUG

static void UFO_RemoveFromGeoscape_f (void)
{
    if (ccs.numUFOs > 0)
        UFO_RemoveFromGeoscape(ccs.ufos);
}
#endif

void UFO_DetectNewUFO (aircraft_t* ufocraft)
{
    if (ufocraft->detected)
        return;

    /* Make this UFO detected */
    if (!ufocraft->detectionIdx) {
        ufocraft->detectionIdx = ++ccs.campaignStats.ufosDetected;
    }
    ufocraft->detected = true;
    ufocraft->lastSpotted = ccs.date;

    /* If this is the first UFO on geoscape, activate radar */
    if (!GEO_IsRadarOverlayActivated())
        GEO_SetOverlay("radar", 1);

    CP_TriggerEvent(UFO_DETECTION, cgi->Com_UFOTypeToShortName(ufocraft->getUfoType()));

    GEO_UpdateGeoscapeDock();
}

bool UFO_CampaignCheckEvents (void)
{
    bool newDetection;
    aircraft_t* ufo;

    newDetection = false;

    /* For each ufo in geoscape */
    ufo = nullptr;
    while ((ufo = UFO_GetNext(ufo)) != nullptr) {
        char detectedBy[MAX_VAR] = "";
        float minDistance = -1;
        /* detected tells us whether or not a UFO is detected NOW, whereas ufo->detected tells
         * us whether or not the UFO was detected PREVIOUSLY. */
        bool detected = false;
        base_t* base;

        /* don't update UFO status id UFO is landed or crashed */
        if (ufo->landed)
            continue;

        /* note: We can't exit these loops as soon as we found the UFO detected
         * RADAR_CheckUFOSensored registers the UFO in every radars' detection list
         * which detect it */

        /* Check if UFO is detected by an aircraft */
        AIR_Foreach(aircraft) {
            if (!AIR_IsAircraftOnGeoscape(aircraft))
                continue;
            /* maybe the ufo is already detected, don't reset it */
            if (RADAR_CheckUFOSensored(&aircraft->radar, aircraft->pos, ufo, detected | ufo->detected)) {
                const int distance = GetDistanceOnGlobe(aircraft->pos, ufo->pos);
                detected = true;
                if (minDistance < 0 || minDistance > distance) {
                    minDistance = distance;
                    Q_strncpyz(detectedBy, aircraft->name, sizeof(detectedBy));
                }
            }
        }

        /* Check if UFO is detected by a base */
        base = nullptr;
        while ((base = B_GetNext(base)) != nullptr) {
            if (!B_GetBuildingStatus(base, B_POWER))
                continue;

            /* maybe the ufo is already detected, don't reset it */
            if (RADAR_CheckUFOSensored(&base->radar, base->pos, ufo, detected | ufo->detected)) {
                const int distance = GetDistanceOnGlobe(base->pos, ufo->pos);
                detected = true;
                if (minDistance < 0 || minDistance > distance) {
                    minDistance = distance;
                    Q_strncpyz(detectedBy, base->name, sizeof(detectedBy));
                }
            }

        }

        /* Check if UFO is detected by a radartower */
        INS_Foreach(installation) {
            /* maybe the ufo is already detected, don't reset it */
            if (RADAR_CheckUFOSensored(&installation->radar, installation->pos, ufo, detected | ufo->detected)) {
                const int distance = GetDistanceOnGlobe(installation->pos, ufo->pos);
                detected = true;
                if (minDistance < 0 || minDistance > distance) {
                    minDistance = distance;
                    Q_strncpyz(detectedBy, installation->name, sizeof(detectedBy));
                }
            }
        }

        /* Check if ufo appears or disappears on radar */
        if (detected != ufo->detected) {
            if (detected) {
                UFO_DetectNewUFO(ufo);
                /* if UFO is aiming a PHALANX aircraft, warn player */
                if (ufo->aircraftTarget) {
                    /* stop time and notify */
                    MSO_CheckAddNewMessage(NT_UFO_ATTACKING, _("Notice"), va(_("%s is flying toward %s"), UFO_GetName(ufo), ufo->aircraftTarget->name));
                } else {
                    MSO_CheckAddNewMessage(NT_UFO_SPOTTED, _("Notice"), va(_("Our radar detected %s near %s"), UFO_GetName(ufo), detectedBy), MSG_UFOSPOTTED);
                }
                newDetection = true;
            } else if (!detected) {
                MSO_CheckAddNewMessage(NT_UFO_SIGNAL_LOST, _("Notice"), va(_("Our radar has lost the tracking on %s"), UFO_GetName(ufo)), MSG_UFOLOST);
                /* Make this UFO undetected */
                ufo->detected = false;
                /* Notify that ufo disappeared */
                AIR_AircraftsUFODisappear(ufo);
                GEO_NotifyUFODisappear(ufo);

                /* Deactivate Radar overlay */
                RADAR_DeactivateRadarOverlay();
            }
        }
    }
    return newDetection;
}

void UFO_NotifyPhalanxAircraftRemoved (const aircraft_t* const aircraft)
{
    assert(aircraft);

    for (int ufoIdx = 0; ufoIdx < ccs.numUFOs; ufoIdx++) {
        aircraft_t* ufo = UFO_GetByIDX(ufoIdx);

        if (ufo->aircraftTarget == aircraft)
            ufo->aircraftTarget = nullptr;
    }
}

bool UFO_IsUFOSeenOnGeoscape (const aircraft_t* ufo)
{
    bool seen = !ufo->landed && ufo->detected;
#ifdef DEBUG
    if (seen && ufo->notOnGeoscape)
        cgi->Com_Error(ERR_DROP, "UFO_IsUFOSeenOnGeoscape: ufo %s can't be used on geoscape", ufo->id);
#endif
    return seen;
}

static const cmdList_t ufoDebugCallbacks[] = {
#ifdef DEBUG
    {"debug_destroyufos", UFO_DestroyUFOs_f, "Destroys all UFOs on the geoscape"},
    {"debug_listufo", UFO_ListOnGeoscape_f, "Print UFO information to game console"},
    {"debug_removeufo", UFO_RemoveFromGeoscape_f, "Remove a UFO from geoscape"},
#endif
    {nullptr, nullptr, nullptr}
};

void UFO_InitStartup (void)
{
    UFO_InitCallbacks();
    cgi->Cmd_TableAddList(ufoDebugCallbacks);
#ifdef DEBUG
    cgi->Cvar_Get("debug_showufos", "0", CVAR_DEVELOPER, "Show all UFOs on geoscape");
#endif
}

void UFO_Shutdown (void)
{
    UFO_ShutdownCallbacks();
    cgi->Cmd_TableRemoveList(ufoDebugCallbacks);
}