/*  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
    ========
    Drop Ship (orbit/surface and surface/orbit) AI class
*/

#include "DropShipAI.h"
#include "TacticalAI.h"
#include "Ship.h"
#include "ShipCtrl.h"
#include "Drive.h"
#include "Sim.h"
#include "StarSystem.h"
#include "KeyMap.h"

#include "Game.h"

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

DropShipAI::DropShipAI(Ship* s)
    : ShipAI(s)
{
    seek_gain = 20;
    seek_damp = 0.5;

    delete tactical;
    tactical = 0;
}

DropShipAI::~DropShipAI()
{
}

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

void
DropShipAI::FindObjective()
{
    distance = 0;

    if (!ship)  return;

    Sim*        sim = Sim::GetSim();
    SimRegion*  self_rgn = ship->GetRegion();

    // if making orbit, go up:
    if (self_rgn->Type() == Sim::AIR_SPACE) {
        obj_w = self->Location() + Point(0, 1e3, 0);
    }

    // if breaking orbit, head for terrain region:
    else {
        SimRegion* dst_rgn = sim->FindNearestTerrainRegion(ship);
        Point      dst     = dst_rgn->GetOrbitalRegion()->Location() -
        self_rgn->GetOrbitalRegion()->Location() +
        Point(0, 0, -1e6);

        obj_w =    dst.OtherHand();
    }

    // distance from self to navpt:
    distance = Point(obj_w - self->Location()).length();

    // transform into camera coords:
    objective = Transform(obj_w);
    objective.Normalize();
}

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

void
DropShipAI::Navigator()
{
    accumulator.Clear();
    magnitude = 0;

    if (other)
    ship->SetFLCSMode(Ship::FLCS_AUTO);
    else
    ship->SetFLCSMode(Ship::FLCS_MANUAL);

    Accumulate(AvoidCollision());
    Accumulate(Seek(objective));

    // are we being asked to flee?
    if (fabs(accumulator.yaw) == 1.0 && accumulator.pitch == 0.0) {
        accumulator.pitch  = -0.7f;
        accumulator.yaw   *= 0.25f;
    }

    self->ApplyRoll((float) (accumulator.yaw * -0.4));
    self->ApplyYaw((float) (accumulator.yaw * 0.2));

    if (fabs(accumulator.yaw) > 0.5 && fabs(accumulator.pitch) < 0.1)
    accumulator.pitch -= 0.1f;

    if (accumulator.pitch != 0)
    self->ApplyPitch((float) accumulator.pitch);

    // if not turning, roll to orient with world coords:
    if (fabs(accumulator.yaw) < 0.1) {
        Point vrt = ((Camera*) &(self->Cam()))->vrt();
        double deflection = vrt.y;
        if (deflection != 0) {
            double theta = asin(deflection/vrt.length());
            self->ApplyRoll(-theta);
        }
    }

    ship->SetThrottle(100);
    ship->ExecFLCSFrame();
}