/*  Starshatter OpenSource Distribution
    Copyright (c) 1997-2004, Destroyer Studios LLC.
    All Rights Reserved.

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    modification, are permitted provided that the following conditions are met:

    * Redistributions of source code must retain the above copyright notice,
      this list of conditions and the following disclaimer.
    * Redistributions in binary form must reproduce the above copyright notice,
      this list of conditions and the following disclaimer in the documentation
      and/or other materials provided with the distribution.
    * Neither the name "Destroyer Studios" nor the names of its contributors
      may be used to endorse or promote products derived from this software
      without specific prior written permission.

    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
    AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
    IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
    ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
    LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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    ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
    POSSIBILITY OF SUCH DAMAGE.

    SUBSYSTEM:    Stars.exe
    FILE:         Debris.cpp
    AUTHOR:       John DiCamillo


    OVERVIEW
    ========
    Debris Sprite animation class
*/

#include "MemDebug.h"
#include "Debris.h"
#include "Shot.h"
#include "Explosion.h"
#include "Sim.h"
#include "StarSystem.h"
#include "Terrain.h"

#include "Solid.h"
#include "Bitmap.h"
#include "DataLoader.h"
#include "Game.h"
#include "Random.h"

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

Debris::Debris(Model* model, const Vec3& pos, const Vec3& vel, double m)
: SimObject("Debris", SimObject::SIM_DEBRIS)
{
    MoveTo(pos);

    velocity  = vel;
    mass      = (float) m;
    integrity = mass * 10.0f;
    life      = 300;

    Solid* solid = new(__FILE__,__LINE__) Solid;

    if (solid) {
        solid->UseModel(model);
        solid->MoveTo(pos);

        rep = solid;

        radius = solid->Radius();
    }

    Point torque = RandomVector(Mass()/2);

    if (Mass() < 10)
    torque *= (rand() / 3200);
    else if (Mass() > 10e3)
    torque *= 0.25;
    else if (Mass() > 10e6)
    torque *= 0.005;

    ApplyTorque(torque);
}

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

int
Debris::HitBy(Shot* shot, Point& impact)
{
    if (!shot->IsArmed()) return 0;

    const int HIT_NOTHING   = 0;
    const int HIT_HULL      = 1;

    Point    hull_impact;
    int      hit_type = HIT_NOTHING;
    bool     hit_hull = true;
    Point    shot_loc = shot->Location();
    Point    delta    = shot_loc - Location();
    double   dlen     = delta.length();
    double   dscale   = 1;
    float    scale    = 1.0f;
    Sim*     sim      = Sim::GetSim();

    // MISSILE PROCESSING ------------------------------------------------

    if (shot->IsMissile()) {
        if (dlen < Radius()) {
            hull_impact = impact = shot_loc;
            sim->CreateExplosion(impact, Velocity(), Explosion::HULL_FLASH,   0.3f * scale, scale, region, this);
            sim->CreateExplosion(impact, Point(),    Explosion::SHOT_BLAST,   2.0f,         scale, region);
            hit_type = HIT_HULL;
        }
    }

    // ENERGY WEP PROCESSING ---------------------------------------------

    else {

        Solid* solid = (Solid*) rep;

        Point  shot_loc = shot->Location();
        Point  shot_vpn = shot_loc - shot->Origin();
        double shot_len = shot_vpn.Normalize();
        if (shot_len == 0) shot_len = 1000;

        // impact:
        if (solid) {
            if (solid->CheckRayIntersection(shot->Origin(), shot_vpn, shot_len, impact)) {
                // trim beam shots to impact point:
                if (shot->IsBeam())
                shot->SetBeamPoints(shot->Origin(), impact);

                hull_impact = impact;

                if (shot->IsBeam())
                sim->CreateExplosion(impact, Velocity(), Explosion::BEAM_FLASH, 0.30f * scale, scale, region, this);
                else
                sim->CreateExplosion(impact, Velocity(), Explosion::HULL_FLASH, 0.30f * scale, scale, region, this);

                Point burst_vel = hull_impact - Location();
                burst_vel.Normalize();
                burst_vel *= Radius() * 0.5;
                burst_vel += Velocity();

                sim->CreateExplosion(hull_impact, burst_vel, Explosion::HULL_BURST, 0.50f * scale, scale, region, this);

                hit_type = HIT_HULL;
                hit_hull = true;
            }
        }

        else {
            if (dlen < Radius()) {
                hull_impact = impact = shot_loc;

                if (shot->IsBeam())
                sim->CreateExplosion(impact, Velocity(), Explosion::BEAM_FLASH, 0.30f * scale, scale, region, this);
                else
                sim->CreateExplosion(impact, Velocity(), Explosion::HULL_FLASH, 0.30f * scale, scale, region, this);

                hit_type = HIT_HULL;
            }
        }
    }

    // DAMAGE RESOLUTION -------------------------------------------------

    if (hit_type != HIT_NOTHING) {
        double effective_damage = shot->Damage() * dscale;

        if (shot->IsBeam()) {
            effective_damage *= Game::FrameTime();
        }
        else {
            ApplyTorque(shot->Velocity() * (float) effective_damage * 1e-6f);
        }

        if (effective_damage > 0)
        Physical::InflictDamage(effective_damage);
    }

    return hit_type;
}

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

void
Debris::ExecFrame(double seconds)
{
    if (GetRegion()->Type() == SimRegion::AIR_SPACE) {
        if (AltitudeAGL() < Radius()) {
            velocity          = Point();
            arcade_velocity   = Point();

            Terrain* terrain  = region->GetTerrain();

            if (terrain) {
                Point loc = Location();
                MoveTo(Point(loc.x, terrain->Height(loc.x, loc.z), loc.z));
            }
        }
        else {
            if (mass > 100) {
                Orbital* primary = GetRegion()->GetOrbitalRegion()->Primary();

                const double   GRAV = 6.673e-11;
                double         m0   = primary->Mass();
                double         r    = primary->Radius();

                SetDrag(0.001);
                SetGravity(6 * GRAV * m0 / (r*r));  // accentuate gravity
                SetBaseDensity(1.0f);
            }

            AeroFrame(seconds);
        }
    }
    else {
        Physical::ExecFrame(seconds);
    }
}

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

double
Debris::AltitudeAGL() const
{
    Point    loc          = Location();
    double   altitude_agl = loc.y;

    Terrain* terrain      = region->GetTerrain();

    if (terrain)
    altitude_agl -= terrain->Height(loc.x, loc.z);

    if (!_finite(altitude_agl))
    altitude_agl = 0;

    return altitude_agl;
}