/*  Starshatter: The Open Source Project
    Copyright (c) 2021-2024, Starshatter: The Open Source Project Contributors
    Copyright (c) 2011-2012, Starshatter OpenSource Distribution Contributors
    Copyright (c) 1997-2006, Destroyer Studios LLC.

    AUTHOR:       John DiCamillo


    OVERVIEW
    ========
    "Air Boss" AI class for managing carrier fighter squadrons
*/

#include "CarrierAI.h"
#include "ShipAI.h"
#include "Ship.h"
#include "ShipDesign.h"
#include "Element.h"
#include "FlightPlanner.h"
#include "Instruction.h"
#include "RadioMessage.h"
#include "RadioTraffic.h"
#include "Hangar.h"
#include "FlightDeck.h"
#include "Mission.h"
#include "Contact.h"
#include "Sim.h"
#include "StarSystem.h"
#include "Callsign.h"
#include "NetUtil.h"

#include "Clock.h"
#include "Random.h"

// +----------------------------------------------------------------------+

CarrierAI::CarrierAI(Ship* s, int level)
    : sim(0), ship(s), hangar(0), exec_time(0), flight_planner(0),
      hold_time(0), ai_level(level)
{
    if (ship) {
        sim      = Sim::GetSim();
        hangar = ship->GetHangar();

        for (int i = 0; i < 4; i++)
        patrol_elem[i] = 0;

        if (ship)
        flight_planner = new FlightPlanner(ship);

        hold_time = (int) Clock::GetInstance()->GameTime();
    }
}

CarrierAI::~CarrierAI()
{
    delete flight_planner;
}

// +--------------------------------------------------------------------+

void
CarrierAI::ExecFrame(double secs)
{
    const int INIT_HOLD   = 15000;
    const int EXEC_PERIOD =  3000;

    if (!sim || !ship || !hangar)
    return;

    if (((int) Clock::GetInstance()->GameTime() - hold_time >= INIT_HOLD) &&
            ((int) Clock::GetInstance()->GameTime() - exec_time >  EXEC_PERIOD)) {

        CheckHostileElements();
        CheckPatrolCoverage();

        exec_time = (int) Clock::GetInstance()->GameTime();
    }
}

// +--------------------------------------------------------------------+

bool
CarrierAI::CheckPatrolCoverage()
{
    const DWORD PATROL_PERIOD = 900 * 1000;

    // pick up existing patrol elements:

    ListIter<Element> iter = sim->GetElements();
    while (++iter) {
        Element* elem = iter.value();

        if (elem->GetCarrier()   == ship                   &&
                (elem->Type()         == Mission::PATROL        ||
                    elem->Type()         == Mission::SWEEP         ||
                    elem->Type()         == Mission::AIR_PATROL    ||
                    elem->Type()         == Mission::AIR_SWEEP)    &&
                !elem->IsSquadron()                             &&
                !elem->IsFinished()) {

            bool found = false;
            int  open  = -1;

            for (int i = 0; i < 4; i++) {
                if (patrol_elem[i] == elem)
                found = true;

                else if (patrol_elem[i] == 0 && open < 0)
                open = i;
            }

            if (!found && open >= 0) {
                patrol_elem[open] = elem;
            }
        }
    }

    // manage the four screening patrols:

    for (int i = 0; i < 4; i++) {
        Element* elem = patrol_elem[i];

        if (elem) {
            if (elem->IsFinished()) {
                patrol_elem[i] = 0;
            }

            else {
                LaunchElement(elem);
            }
        }

        else if (Clock::GetInstance()->GameTime() - hangar->GetLastPatrolLaunch() > PATROL_PERIOD ||
                hangar->GetLastPatrolLaunch() == 0) {
            Element* patrol = CreatePackage(0, 2, Mission::PATROL, 0, "ACM Medium Range");
            if (patrol) {
                patrol_elem[i] = patrol;

                if (flight_planner)
                flight_planner->CreatePatrolRoute(patrol, i);

                hangar->SetLastPatrolLaunch(Clock::GetInstance()->GameTime());
                return true;
            }
        }
    }

    return false;
}

// +--------------------------------------------------------------------+

bool
CarrierAI::CheckHostileElements()
{
    List<Element>     assigned;
    ListIter<Element> iter = sim->GetElements();
    while (++iter) {
        Element* elem = iter.value();

        // if this element is hostile to us
        // or if the element is a target objective
        // of the carrier, or is hostile to any
        // of our squadrons...

        bool hostile = false;

        if (elem->IsHostileTo(ship) || elem->IsObjectiveTargetOf(ship)) {
            hostile = true;
        }
        else {
            for (int i = 0; i < hangar->NumSquadrons() && !hostile; i++) {
                int squadron_iff = hangar->SquadronIFF(i);

                if (elem->IsHostileTo(squadron_iff))
                hostile = true;
            }
        }

        if (hostile) {
            sim->GetAssignedElements(elem, assigned);

            // is one of our fighter elements already assigned to this target?
            bool found = false;
            ListIter<Element> a_iter = assigned;
            while (++a_iter && !found) {
                Element* a = a_iter.value();

                if (a->GetCarrier() == ship)
                found = true;
            }

            // nobody is assigned yet, create an attack package
            if (!found && CreateStrike(elem)) {
                hold_time = (int) Clock::GetInstance()->GameTime() + 30000;
                return true;
            }
        }
    }

    return false;
}

bool
CarrierAI::CreateStrike(Element* elem)
{
    Element* strike = 0;
    Ship*    target = elem->GetShip(1);

    if (target && !target->IsGroundUnit()) {
        Contact* contact = ship->FindContact(target);
        if (contact && contact->GetIFF(ship) > 0) {

            // fighter intercept
            if (target->IsDropship()) {
                int squadron = 0;
                if (hangar->NumShipsReady(1) >= hangar->NumShipsReady(0))
                squadron = 1;

                int count = 2;

                if (count < elem->NumShips())
                count = elem->NumShips();

                strike = CreatePackage(squadron, count, Mission::INTERCEPT, elem->Name(), "ACM Medium Range");

                if (strike) {
                    strike->SetAssignment(elem);

                    if (flight_planner)
                    flight_planner->CreateStrikeRoute(strike, elem);
                }
            }

            // starship or station assault
            else {
                int squadron = 0;
                if (hangar->NumSquadrons() > 1)
                squadron = 1;
                if (hangar->NumSquadrons() > 2)
                squadron = 2;

                int count = 2;

                if (target->Class() > Ship::FRIGATE) {
                    count = 4;
                    strike = CreatePackage(squadron, count, Mission::ASSAULT, elem->Name(), "Hvy Ship Strike");
                }
                else {
                    count = 2;
                    strike = CreatePackage(squadron, count, Mission::ASSAULT, elem->Name(), "Ship Strike");
                }

                if (strike) {
                    strike->SetAssignment(elem);

                    if (flight_planner)
                    flight_planner->CreateStrikeRoute(strike, elem);

                    // strike escort if target has fighter protection:
                    if (target->GetHangar()) {
                        if (squadron > 1) squadron--;
                        Element* escort = CreatePackage(squadron, 2, Mission::ESCORT_STRIKE, strike->Name(), "ACM Short Range");

                        if (escort && flight_planner)
                        flight_planner->CreateEscortRoute(escort, strike);
                    }
                }
            }
        }
    }

    return strike != 0;
}

// +--------------------------------------------------------------------+

Element*
CarrierAI::CreatePackage(int squadron, int size, int code, const char* target, const char* loadname)
{
    if (squadron < 0 || size < 1 || code < Mission::PATROL || hangar->NumShipsReady(squadron) < size)
    return 0;

    Sim*        sim    = Sim::GetSim();
    const char* call   = sim->FindAvailCallsign(ship->GetIFF());
    Element*    elem   = sim->CreateElement(call, ship->GetIFF(), code);
    FlightDeck* deck   = 0;
    int         queue  = 1000;
    int*        load   = 0;
    const ShipDesign*
    design = hangar->SquadronDesign(squadron);

    elem->SetSquadron(hangar->SquadronName(squadron));
    elem->SetCarrier(ship);

    if (target) {
        int i_code = 0;

        switch (code) {
        case Mission::ASSAULT:     i_code = Instruction::ASSAULT;   break;
        case Mission::STRIKE:      i_code = Instruction::STRIKE;    break;

        case Mission::AIR_INTERCEPT:
        case Mission::INTERCEPT:   i_code = Instruction::INTERCEPT; break;

        case Mission::ESCORT:
        case Mission::ESCORT_STRIKE:
        case Mission::ESCORT_FREIGHT:
            i_code = Instruction::ESCORT;    break;

        case Mission::DEFEND:      i_code = Instruction::DEFEND;    break;
        }

        Instruction* objective = new Instruction(i_code, target);
        if (objective)
        elem->AddObjective(objective);
    }

    if (design && loadname) {
        Text name = loadname;
        name.setSensitive(false);

        ListIter<ShipLoad> sl = (List<ShipLoad>&) design->loadouts;
        while (++sl) {
            if (name == sl->name) {
                load = sl->load;
                elem->SetLoadout(load);
            }
        }
    }

    for (int i = 0; i < ship->NumFlightDecks(); i++) {
        FlightDeck* d = ship->GetFlightDeck(i);

        if (d && d->IsLaunchDeck()) {
            int dq = hangar->PreflightQueue(d);

            if (dq < queue) {
                queue = dq;
                deck  = d;
            }
        }
    }

    int npackage = 0;
    int slots[4];

    for (int i = 0; i < 4; i++)
    slots[i] = -1;

    for (int slot = 0; slot < hangar->SquadronSize(squadron); slot++) {
        const HangarSlot* s = hangar->GetSlot(squadron, slot);

        if (hangar->GetState(s) == Hangar::STORAGE) {
            if (npackage < 4)
            slots[npackage] = slot;

            hangar->GotoAlert(squadron, slot, deck, elem, load, code > Mission::SWEEP);
            npackage++;

            if (npackage >= size)
            break;
        }
    }

    NetUtil::SendElemCreate(elem, squadron, slots, code <= Mission::SWEEP);

    return elem;
}

// +--------------------------------------------------------------------+

bool
CarrierAI::LaunchElement(Element* elem)
{
    bool result = false;

    if (!elem)
    return result;

    for (int squadron = 0; squadron < hangar->NumSquadrons(); squadron++) {
        for (int slot = 0; slot < hangar->SquadronSize(squadron); slot++) {
            const HangarSlot* s = hangar->GetSlot(squadron, slot);

            if (hangar->GetState(s) == Hangar::ALERT &&
                    hangar->GetPackageElement(s) == elem) {

                hangar->Launch(squadron, slot);
                NetUtil::SendShipLaunch(ship, squadron, slot);

                result = true;
            }
        }
    }

    return result;
}