/*
   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: Benjamin Grauer
   co-programmer: ...
*/

#define DEBUG_SPECIAL_MODULE DEBUG_MODULE_GRAPHICS

#include "particle_system.h"

#include "particle_emitter.h"

#include "field.h"
#include "model.h"

#include "load_param.h"
#include "factory.h"
#include "material.h"
#include "state.h"
#include "shell_command.h"

#include "parser/tinyxml/tinyxml.h"
#include <algorithm>

using namespace std;
/**
 *  standard constructor
 * @param maxCount the Count of particles in the System
 * @param type The Type of the ParticleSystem
*/
ParticleSystem::ParticleSystem (unsigned int maxCount)
{
  this->init();

  this->setMaxCount(maxCount);
}

/**
 *  standard deconstructor
*/
ParticleSystem::~ParticleSystem()
{
  // deleting all the living Particles
  while (this->particles)
  {
    Particle* tmpDelPart = this->particles;
    this->particles = this->particles->next;
    delete tmpDelPart;
  }

  // deleting all the dead particles
  while (this->deadList)
  {
    Particle* tmpDelPart = this->deadList;
    this->deadList = this->deadList->next;
    delete tmpDelPart;
  }

  while(!this->emitters.empty())
  {
    this->removeEmitter(this->emitters.front());
  }

}

/**
 * @brief initializes the ParticleSystem with default values
 */
void ParticleSystem::init()
{
  this->setClassID(CL_PARTICLE_SYSTEM, "ParticleSystem");

  this->setMaxCount(PARTICLE_DEFAULT_MAX_COUNT);
  this->count = 0;
  this->particles = NULL;
  this->deadList = NULL;
  this->setConserve(1);
  this->setLifeSpan(1);

  this->toList(OM_ENVIRON);
}


/**
 * loads Parameters from a TiXmlElement
 * @param root the XML-element to load from.
 */
void ParticleSystem::loadParams(const TiXmlElement* root)
{
  WorldEntity::loadParams(root);
  PhysicsInterface::loadParams(root);

  LoadParam(root, "max-count", this, ParticleSystem, setMaxCount)
  .describe("the maximal count of Particles, that can be emitted into this system");

  LoadParam(root, "life-span", this, ParticleSystem, setLifeSpan)
  .describe("sets the life-span of the Particles.");

  LoadParam(root, "conserve", this, ParticleSystem, setConserve)
  .describe("sets the Conserve factor of the Particles (1.0: they keep all their energy, 0.0:they keep no energy)");

  LoadParamXML(root, "emitters", this, ParticleSystem, loadEmitters);

  LOAD_PARAM_START_CYCLE(root, element);
  {
    element->ToText();
    // PER-PARTICLE-ATTRIBUTES:
    LoadParam_CYCLE(element, "radius", this, ParticleSystem, setRadius)
    .describe("The Radius of each particle over time (TimeIndex [0-1], radius at TimeIndex, randomRadius at TimeIndex)");

    LoadParam_CYCLE(element, "mass", this, ParticleSystem, setMass)
    .describe("The Mass of each particle over time (TimeIndex: [0-1], mass at TimeIndex, randomMass at TimeIndex)");

    LoadParam_CYCLE(element, "color", this, ParticleSystem, setColor)
    .describe("The Color of each particle over time (TimeIndex: [0-1], red: [0-1], green: [0-1], blue: [0-1], alpha: [0-1])");
  }
  LOAD_PARAM_END_CYCLE(element);

  LoadParam(root, "precache", this, ParticleSystem, precache)
      .describe("Precaches the ParticleSystem for %1 seconds, %2 times per Second")
      .defaultValues(2, 1, 25);
}

/**
 * @brief loads the Emitters from An XML-Root
 * @param root the XML-Element to load all emitters from
 */
void ParticleSystem::loadEmitters(const TiXmlElement* root)
{
  LOAD_PARAM_START_CYCLE(root, element);
  {
    BaseObject* emitter = Factory::fabricate(element);
    if (emitter->isA(CL_PARTICLE_EMITTER))
      this->addEmitter(dynamic_cast<ParticleEmitter*>(emitter));
    else
    {
      PRINTF(2)("Tried to load an Element of type '%s' that should be a ParticleEmitter onto '%s::%s'.\n",
                emitter->getClassName(), this->getClassName(), this->getName());
      delete emitter;
    }
  }
  LOAD_PARAM_END_CYCLE(element);
}

/**
* @param maxCount the maximum count of particles that can be emitted
 */
void ParticleSystem::setMaxCount(int maxCount)
{
  this->maxCount = maxCount;
}

// setting properties
/**
 *  Sets the lifespan of newly created particles
*/
void ParticleSystem::setLifeSpan(float lifeSpan, float randomLifeSpan)
{
  this->lifeSpan = lifeSpan;
  this->randomLifeSpan = randomLifeSpan;
}

/**
 *  sets the conserve Factor of newly created particles
*/
void ParticleSystem::setConserve(float conserve)
{
  if (conserve > 1.0)
    this->conserve = 1.0;
  else if (conserve < 0.0)
    this->conserve = 0.0;
  else
    this->conserve = conserve;
}

/////////////////////////////
/* Per-Particle Attributes */
/////////////////////////////
/**
 *  sets a key in the radius-animation on a per-particle basis
 * @param lifeCycleTime the time (partilceLifeTime/particleAge) [0-1]
 * @param radius the radius at this position
 * @param randRadius the randRadius at this position
*/
void ParticleSystem::setRadius(float lifeCycleTime, float radius, float randRadius)
{
  this->radiusAnim.changeEntry(lifeCycleTime, radius);
  this->randRadiusAnim.changeEntry(lifeCycleTime, randRadius);
}

/**
 *  sets a key in the mass-animation on a per-particle basis
 * @param lifeCycleTime the time (partilceLifeTime/particleAge) [0-1]
 * @param mass the mass at this position
 * @param randMass the randomMass at this position
*/
void ParticleSystem::setMass(float lifeCycleTime, float mass, float randMass)
{
  this->massAnim.changeEntry(lifeCycleTime, mass);
  this->randMassAnim.changeEntry(lifeCycleTime, randMass);
}

/**
 *  sets a key in the color-animation on a per-particle basis
 * @param lifeCycleTime: the time (partilceLifeTime/particleAge) [0-1]
 * @param red: red
 * @param green: green
 * @param blue: blue
 * @param alpha: alpha
*/
void ParticleSystem::setColor(float lifeCycleTime, float red, float green, float blue, float alpha)
{
  this->colorAnim[0].changeEntry(lifeCycleTime, red);
  this->colorAnim[1].changeEntry(lifeCycleTime, green);
  this->colorAnim[2].changeEntry(lifeCycleTime, blue);
  this->colorAnim[3].changeEntry(lifeCycleTime, alpha);
}

/**
 * @brief adds an Emitter to this System.
 * @param emitter the Emitter to add.
 */
void ParticleSystem::addEmitter(ParticleEmitter* emitter)
{
  assert (emitter != NULL);
  if (emitter->getSystem() != NULL)
    emitter->getSystem()->removeEmitter(emitter);
  emitter->system = this;
  this->emitters.push_back(emitter);
}

/**
 * @brief removes a ParticleEmitter from this System
 * @param emitter the Emitter to remove
 */
void ParticleSystem::removeEmitter(ParticleEmitter* emitter)
{
  assert (emitter != NULL);
  emitter->system = NULL;
  this->emitters.remove(emitter);
  /*  std::list<ParticleEmitter*>::iterator it = std::find(this->emitters.begin(), this->emitters.end(), emitter);
  if (it != this->emitters.end())
    this->emitters.erase(it);*/
}

/**
 * @brief does a Precaching, meaning, that the ParticleSystem(and its emitters) will be ticked force
 * @param seconds: seconds
 * @param ticksPerSeconds times per Second.
 */
void ParticleSystem::precache(unsigned int seconds, unsigned int ticksPerSecond)
{

  std::list<ParticleEmitter*>::iterator emitter;
  for (emitter = this->emitters.begin(); emitter != this->emitters.end(); emitter++)
    (*emitter)->updateNode(.1), (*emitter)->updateNode(.1);

  PRINTF(4)("Precaching %s::%s %d seconds %d timesPerSecond\n", this->getClassName(), this->getName(), seconds, ticksPerSecond);
  this->debug();
  for (unsigned int i = 0; i < seconds*ticksPerSecond; i++)
    this->tick(1.0/(float)ticksPerSecond);
}


/**
 *  ticks the system.
 * @param dt the time to tick all the Particles of the System

   this is used to get all the particles some motion
*/
void ParticleSystem::tick(float dt)
{
  Particle* tickPart = particles;  // the particle to Tick
  Particle* prevPart = NULL;
  while (likely(tickPart != NULL))
  {
    // applying force to the System.
    if (likely (tickPart->mass > 0.0))
      tickPart->velocity += tickPart->extForce / tickPart->mass * dt;

    tickPart->radius = radiusAnim.getValue(tickPart->lifeCycle)
                       + randRadiusAnim.getValue(tickPart->lifeCycle) * tickPart->radiusRand;

    tickPart->mass = massAnim.getValue(tickPart->lifeCycle)
                     + randMassAnim.getValue(tickPart->lifeCycle) * tickPart->massRand;

    tickPart->extForce = Vector(0,0,0);

    // applying Color
    tickPart->color[0] = this->colorAnim[0].getValue(tickPart->lifeCycle);
    tickPart->color[1] = this->colorAnim[1].getValue(tickPart->lifeCycle);
    tickPart->color[2] = this->colorAnim[2].getValue(tickPart->lifeCycle);
    tickPart->color[3] = this->colorAnim[3].getValue(tickPart->lifeCycle);

    // rendering new position.
    tickPart->position += tickPart->velocity * dt;
    tickPart->orientation += tickPart->momentum *dt;

    // many more to come

    if (this->conserve < 1.0)
    {
      tickPart->velocity *= this->conserve;
      tickPart->momentum *= this->conserve;
    }
    // find out if we have to delete tickPart
    if (unlikely((tickPart->lifeCycle += dt/tickPart->lifeTime) >= 1.0))
    {
      // remove the particle from the list
      if (likely(prevPart != NULL))
      {
        prevPart->next = tickPart->next;
        tickPart->next = this->deadList;
        this->deadList = tickPart;
        tickPart = prevPart->next;
      }
      else
      {
        prevPart = NULL;
        this->particles = tickPart->next;
        tickPart->next = this->deadList;
        this->deadList = tickPart;
        tickPart = this->particles;
      }
      --this->count;
    }
    else
    {
      prevPart = tickPart;
      tickPart = tickPart->next;
    }
  }

  std::list<ParticleEmitter*>::iterator emitter;
  for (emitter = this->emitters.begin(); emitter != this->emitters.end(); emitter++)
    (*emitter)->tick(dt);
}

/**
  *  applies some force to a Particle.
  * @param field the Field to apply.
 */
void ParticleSystem::applyField(Field* field)
{
  Particle* tickPart = particles;
  while (tickPart)
  {
    tickPart->extForce += field->calcForce(tickPart->position);
    tickPart = tickPart->next;
  }
}


/**
 * @returns the count of Faces of this ParticleSystem
 */
unsigned int ParticleSystem::getFaceCount() const
{
  return this->count;
}


/**
 *  draws all the Particles of this System

   The Cases in this Function all do the same:
   Drawing all the particles with the appropriate Type.
   This is just the fastest Way to do this, but will most likely be changed in the future.
 */
// void ParticleSystem::draw() const
// {
//   glPushAttrib(GL_ENABLE_BIT);
//
//   Particle* drawPart = particles;
//
//   switch (this->particleType)
//   {
//
//     case PARTICLE_MODEL:
//       {
//       }
//       break;
//
//     case PARTICLE_DOT:
//       glDisable(GL_LIGHTING);
//       glBegin(GL_POINTS);
//       while (likely(drawPart != NULL))
//       {
//         glColor4fv(drawPart->color);
//
//         glLineWidth(drawPart->radius);
//
//         glVertex3f(drawPart->position.x, drawPart->position.y, drawPart->position.z);
//         drawPart = drawPart->next;
//       }
//       glEnd();
//       break;
//   }
//   glPopAttrib();
// }

/**
 *  adds a new Particle to the System
 * @param position the initial position, where the particle gets emitted.
 * @param velocity the initial velocity of the particle.
 * @param orientation the initial orientation of the Paritcle.
 * @param momentum the initial momentum of the Particle (the speed of its rotation).
 * @param data some more data given by the emitter
*/
void ParticleSystem::addParticle(const Vector& position, const Vector& velocity, const Quaternion& orientation, const Quaternion& momentum, unsigned int data)
{
  if (this->count <= this->maxCount)
  {
    // if it is the first Particle
    if (unlikely(particles == NULL))
    {
      if (likely(deadList != NULL))
      {
        this->particles = this->deadList;
        deadList = deadList->next;
      }
      else
      {
        PRINTF(5)("Generating new Particle\n");
        this->particles = new Particle;
      }
      this->particles->next = NULL;
    }
    // filling the List from the beginning
    else
    {
      Particle* tmpPart;
      if (likely(deadList != NULL))
      {
        tmpPart = this->deadList;
        deadList = deadList->next;
      }
      else
      {
        PRINTF(5)("Generating new Particle\n");
        tmpPart = new Particle;
      }
      tmpPart->next = this->particles;
      this->particles = tmpPart;
    }
    particles->lifeTime = this->lifeSpan + (float)(rand()/RAND_MAX)* this->randomLifeSpan;
    particles->lifeCycle = 0.0;
    particles->position = position;
    particles->velocity = velocity;

    particles->orientation = orientation;
    particles->momentum = momentum;

    //  particle->rotation = ; //! @todo rotation is once again something to be done.
    particles->massRand = 2*(float)rand()/RAND_MAX -1;
    particles->radiusRand = 2* (float)rand()/RAND_MAX -1;
    particles->mass = this->massAnim.getValue(0.0) + this->randMassAnim.getValue(0.0)*particles->massRand;
    particles->radius = this->radiusAnim.getValue(0.0) + this->randRadiusAnim.getValue(0.0)*particles->radiusRand;

    ++this->count;
  }
  else
    PRINTF(5)("maximum count of particles reached not adding any more\n");
}

/**
 *  outputs some nice debug information
*/
void ParticleSystem::debug() const
{
  PRINT(0)("  ParticleCount: %d emitters: %d, maximumCount: %d :: filled %d%%\n", this->count, this->emitters.size(), this->maxCount, 100*this->count/this->maxCount);
  if (deadList)
  {
    PRINT(0)("  - ParticleDeadList is used: ");
    int i = 1;
    Particle* tmpPart = this->deadList;
    while (tmpPart = tmpPart->next) ++i;
    PRINT(0)("count: %d\n", i);
  }
}