/*
   orxonox - the future of 3D-vertical-scrollers

   Copyright (C) 2004 orx

   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, or (at your option)
   any later version.

   ### File Specific:
   main-programmer: Patrick Boenzli
   co-programmer: ...
*/

#define DEBUG_SPECIAL_MODULE DEBUG_MODULE_COLLISION_REACTION


#include "cr_object_damage.h"
#include "cr_physics_full_walk.h"
#include "cr_physics_ground_walk.h"

#include "collision.h"
#include "collision_event.h"
#include "collision_filter.h"
#include "collision_tube.h"
#include "cr_defs.h"

#include "cr_engine.h"

#include "debug.h"

namespace CoRe
{

  ObjectListDefinition(CREngine);


  /**
   * standard constructor
   */
  CREngine::CREngine ()
      : BaseObject()
  {
    this->registerObject(this, CREngine::_objectList);
    this->setName("CREngine");

    this->init();
  }

  /**
   *  the singleton reference to this class
   */
  CREngine* CREngine::singletonRef = NULL;

  /**
     @brief standard deconstructor
   */
  CREngine::~CREngine ()
  {
    CREngine::singletonRef = NULL;

    if( this->collisionsUnused.size() != CR_MAX_COLLISIONS)
      PRINTF(0)("CollisionReaction Error: Collision cache size missmatch: %i of %i\n", this->collisionsUnused.size(), CR_MAX_COLLISIONS);
    if( this->collisionEventsUnused.size() != CR_MAX_COLLISION_EVENTS)
      PRINTF(0)("CollisionReaction Error: CollisionEvent cache size missmatch: %i of %i\n", this->collisionEventsUnused.size(), CR_MAX_COLLISION_EVENTS);

    this->reset();

    CollisionIterator it1 = this->collisionsUnused.begin();
    for(; it1 < this->collisionsUnused.end(); it1++)
      delete *it1;
    CollisionEventIterator it2 = this->collisionEventsUnused.begin();
    for(; it2 < this->collisionEventsUnused.end(); it2++)
      delete *it2;

    this->collisionsUnused.clear();
    this->collisionEventsUnused.clear();
  }


  /**
   * inits the CREngine to a working state
   */
  void CREngine::init()
  {
    // precaching:
    // create a list of Collisions and CollisionEvents for fast object recycling purposes
    for( int i = 0; i < CR_MAX_COLLISIONS; i++)
      this->collisionsUnused.push_back(new Collision());
    for( int i = 0; i < CR_MAX_COLLISION_EVENTS; i++)
      this->collisionEventsUnused.push_back(new CollisionEvent());


    // push the collision reaction object on the list in the right order

    // physical reactions
    this->_reactionList[CREngine::CR_PHYSICS_MOMENTUM]      = NULL;
    this->_reactionList[CREngine::CR_PHYSICS_STEP_BACK]     = NULL;
    this->_reactionList[CREngine::CR_PHYSICS_GROUND_WALK]   = new CRPhysicsGroundWalk();
    this->_reactionList[CREngine::CR_PHYSICS_FULL_WALK]     = new CRPhysicsFullWalk();
    this->_reactionList[CREngine::CR_PHYSICS_DAMAGE]        = NULL;
    // object based reactions
    this->_reactionList[CREngine::CR_OBJECT_DAMAGE]         = new CRObjectDamage();
    this->_reactionList[CREngine::CR_OBJECT_PICKUP]         = NULL;
    // misc reactions
    this->_reactionList[CREngine::CR_VERTEX_TRAFO]          = NULL;
    this->_reactionList[CREngine::CR_SPECIAL_CALLBACK]      = NULL;
  }


  /**
   * @returns an instance to a collision object. instead of creating new object this ones can be resycled
   */
  Collision* CREngine::popCollisionObject()
  {
    if( !this->collisionsUnused.empty())
    {
      this->collisionsUsed.push_back(this->collisionsUnused.back());
      this->collisionsUnused.pop_back();
      return this->collisionsUsed.back();
    }
    else
    {
      PRINTF(0)("There is no Collision Object left in the precache table, fatal error will cause segfault, change CR_MAX_COLLISIONS\n");
      assert(false);
      return NULL;
    }
  }


  /**
   * @return an instanco of a CollisionEvent object. instead of creating a new object this ones can be used and resycled
   */
  CollisionEvent* CREngine::popCollisionEventObject()
  {
    if( !this->collisionEventsUnused.empty())
    {
      this->collisionEventsUsed.push_back(this->collisionEventsUnused.back());
      this->collisionEventsUnused.pop_back();
      return this->collisionEventsUsed.back();
    }
    else
    {
      PRINTF(0)("There is no Collision Object left in the precache table, fatal error will cause segfault, change CR_MAX_COLLISION_EVENTS\n");
      assert(false);
      return NULL;
    }
  }


  /**
   * handles all collisions in registered in this tube
   */
  void CREngine::handleCollisions()
  {
    // for all collisions:
    CollisionIterator ci = CollisionTube::getInstance()->begin();
    for(; ci < CollisionTube::getInstance()->end(); ci++)
    {
      for( int i = CREngine::CR_PHYSICS_MOMENTUM; i < CREngine::CR_NUMBER; i++)
      {
        if( _reactionList[i] == NULL)
          continue;

//         PRINTF(0)("CR CHECK: collision between: %s, %s\n", (*ci)->getEntityA()->getClassName().c_str(), (*ci)->getEntityB()->getClassName().c_str());

        // check if entity A or B is subscibed for this event
        bool aReact = (*ci)->getEntityA()->isReactive(*(*ci)->getEntityB(), (CREngine::ReactionType)i);
        bool bReact = (*ci)->getEntityB()->isReactive(*(*ci)->getEntityA(), (CREngine::ReactionType)i);

        // store this information
        (*ci)->setEntityACollide(aReact);
        (*ci)->setEntityBCollide(bReact);

        // and execute the reaction
        if(  aReact || bReact)
        {
          this->_reactionList[i]->reactToCollision(*ci);
          //PRINTF(0)("executing reaction: %s, between %s - %s\n", this->_reactionList[i]->getClassName().c_str(), (*ci)->getEntityA()->getClassName().c_str(), (*ci)->getEntityB()->getClassName().c_str());
        }
      }
      (*ci)->reset();
    }

    this->reset();
  }


  /**
   * flushes all the collision lists and puts them to their initial state
   */
  void CREngine::reset()
  {
    CollisionIterator it1 = this->collisionsUsed.begin();
    for(; it1 < this->collisionsUsed.end(); it1++)
      this->collisionsUnused.push_back(*it1);

    CollisionEventIterator it2 = this->collisionEventsUsed.begin();
    for(; it2 < this->collisionEventsUsed.end(); it2++)
      this->collisionEventsUnused.push_back(*it2);

    this->collisionsUsed.clear();
    this->collisionEventsUsed.clear();

    CollisionTube::getInstance()->reset();
  }


  void CREngine::debug()
  {
  }

}