/*
   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 "particle_engine.h"

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

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

#include "tinyxml.h"

CREATE_FACTORY(ParticleSystem, CL_PARTICLE_SYSTEM);
SHELL_COMMAND(texture, ParticleSystem, setMaterialTexture)
    ->defaultValues(1, "maps/evil-flower.png");

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, PARTICLE_TYPE type)
{
  this->init();

  this->setMaxCount(maxCount);
  this->setType(type, 1);
}

/**
 * @brief creates a Particle System out of a XML-element
 * @param root: the XML-element to load from
 */
ParticleSystem::ParticleSystem(const TiXmlElement* root)
{
  this->init();

  this->loadParams(root);
}

/**
 *  standard deconstructor
*/
ParticleSystem::~ParticleSystem()
{
  // delete what has to be deleted here
   ParticleEngine::getInstance()->removeSystem(this);

   // 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;
     }

   if (this->material)
     delete this->material;
}

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

  this->material = NULL;
  this->setMaxCount(PARTICLE_DEFAULT_MAX_COUNT);
  this->count = 0;
  this->particles = NULL;
  this->deadList = NULL;
  this->setConserve(1);
  this->setLifeSpan(1);
  this->glID = NULL;
  this->setType(PARTICLE_DEFAULT_TYPE, 1);
  ParticleEngine::getInstance()->addSystem(this);
}


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

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

  //LoadParam<ParticleSystem>(root, "type", this, &ParticleSystem::setType);
  LoadParam<ParticleSystem>(root, "life-span", this, &ParticleSystem::setLifeSpan)
      .describe("sets the life-span of the Particles.");

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

  LoadParam<ParticleSystem>(root, "type", this, &ParticleSystem::setType)
      .describe("sets the type of the Particles, (dot, spark, sprite or model)");

  const TiXmlElement* element = root->FirstChildElement();
  while (element != NULL)
  {

  // PER-PARTICLE-ATTRIBUTES:
    LoadParam<ParticleSystem>(element, "radius", this, &ParticleSystem::setRadius, true)
        .describe("The Radius of each particle over time (TimeIndex [0-1], radius at TimeIndex, randomRadius at TimeIndex)");

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

    LoadParam<ParticleSystem>(element, "color", this, &ParticleSystem::setColor, true)
        .describe("The Color of each particle over time (TimeIndex: [0-1], red: [0-1], green: [0-1], blue: [0-1], alpha: [0-1])");
    element = element->NextSiblingElement();
  }

}

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


/**
 * @param particleType the type of particles in this System
 * @param count how many particles (in PARTICLE_MULTI-mode)
   @todo this will be different
*/
void ParticleSystem::setType(const char* particleType)
{
  if (!strcmp(particleType, "dot"))
    this->setType(PARTICLE_DOT);
  else if(!strcmp(particleType, "spark"))
    this->setType(PARTICLE_SPARK);
  else if(!strcmp(particleType, "model"))
    this->setType(PARTICLE_MODEL);
  else // if (strcmp(particleType, "SPRITE"))
    this->setType(PARTICLE_SPRITE);
}

/**
 * @param particleType the type of particles in this System
 * @param count how many particles (in PARTICLE_MULTI-mode)
   @todo this MUST be different
*/
void ParticleSystem::setType(PARTICLE_TYPE particleType, int count)
{
  this->particleType = particleType;
  this->dialectCount = count;
  //  if (glID != NULL)
  //    delete glID;

  //  glID = new GLuint[count];
  //  for (int i = 0; i< count; i++)
  //    glID[i] = 0;

  //  glID[0] = glGenLists(count);
  if (this->material)
    delete this->material;
  this->material = NULL;

  switch (this->particleType)
    {
      case PARTICLE_SPRITE:
        this->material = new Material("transperencyMap");
        this->material->setDiffuseMap("maps/radialTransparency.png");
      //  material->setTransparency(.5);
        break;
  }
}

// setting properties
/**
 *  sets the material to an external material
 * @param material: the material to set this material to.

   !! important if the extern material gets deleted it MUST be unregistered here or segfault !!
*/
void ParticleSystem::setMaterial(Material* material)
{
  this->material = material;
}

void ParticleSystem::setMaterialTexture(const char* textureFile)
{
  if (this->material != NULL)
    this->material->setDiffuseMap(textureFile);
}

/**
 *  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);
}

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

      // 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;
        }
    }
}

/**
  *  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
{
  switch (this->particleType)
  {
    case PARTICLE_SPRITE:
      return this->count;
      break;
    case PARTICLE_MODEL:
      if (this->model)
        return this->count * this->model->getFaceCount();
      break;
  }
}


/**
 *  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)
  {
    default:
    case PARTICLE_SPRITE:
      glDisable(GL_LIGHTING);
      glMatrixMode(GL_MODELVIEW);
      glDepthMask(GL_FALSE);

      material->select();
      glBlendFunc(GL_SRC_ALPHA, GL_DST_ALPHA);

      //glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_ENV_MODE, GL_MODULATE);


      while (likely(drawPart != NULL))
      {
        glColor4fv(drawPart->color);
          //! @todo implement a faster code for the look-at Camera algorithm.

        const PNode* camera = State::getCamera();  //!< @todo MUST be different
        Vector cameraPos = camera->getAbsCoor();
        Vector cameraTargetPos = State::getCameraTarget()->getAbsCoor();
        Vector view = cameraTargetPos - cameraPos;
        Vector up = Vector(0, 1, 0);
        up = camera->getAbsDir().apply(up);
        Vector h = up.cross(view);
        Vector v = h.cross(view);
        h.normalize();
        v.normalize();
        v *= .5 * drawPart->radius;
        h *= .5 * drawPart->radius;

        glBegin(GL_TRIANGLE_STRIP);
        glTexCoord2i(1, 1);
        glVertex3f(drawPart->position.x - h.x - v.x,
                   drawPart->position.y - h.y - v.y,
                   drawPart->position.z - h.z - v.z);
        glTexCoord2i(0, 1);
        glVertex3f(drawPart->position.x - h.x + v.x,
                   drawPart->position.y - h.y + v.y,
                   drawPart->position.z - h.z + v.z);
        glTexCoord2i(1, 0);
        glVertex3f(drawPart->position.x + h.x - v.x,
                   drawPart->position.y + h.y - v.y,
                   drawPart->position.z + h.z - v.z);
        glTexCoord2i(0, 0);
        glVertex3f(drawPart->position.x + h.x + v.x,
                   drawPart->position.y + h.y + v.y,
                   drawPart->position.z + h.z + v.z);

        glEnd();

        drawPart = drawPart->next;
      }
      glDepthMask(GL_TRUE);
      break;

    case PARTICLE_SPARK:
      glDisable(GL_LIGHTING);
      glDepthMask(GL_FALSE);
      //glEnable(GL_LINE_SMOOTH);
      glEnable(GL_BLEND);

      glBegin(GL_LINES);
      while (likely(drawPart != NULL))
      {
        glColor4fv(drawPart->color);
        glVertex3f(drawPart->position.x, drawPart->position.y, drawPart->position.z);
        glVertex3f(drawPart->position.x - drawPart->velocity.x * drawPart->radius,
                   drawPart->position.y - drawPart->velocity.y * drawPart->radius,
                   drawPart->position.z - drawPart->velocity.z * drawPart->radius);
        drawPart = drawPart->next;
      }
      glEnd();
      break;

    case PARTICLE_MODEL:
      {
        GLfloat matrix[4][4];

        if (likely(this->model != NULL))
          while (likely(drawPart != NULL))
        {
          glPushMatrix();
          glMatrixMode(GL_MODELVIEW);
          /* move */
          glTranslatef(drawPart->position.x, drawPart->position.y, drawPart->position.z);
          /* scale */
          glScalef(drawPart->radius, drawPart->radius, drawPart->radius);
          /* rotate */
          drawPart->orientation.matrix (matrix);
          glMultMatrixf((float*)matrix);

          this->model->draw();

          glPopMatrix();
          drawPart = drawPart->next;
        }
        else
          PRINTF(2)("no model loaded onto ParticleSystem-%s\n", this->getName());
      }
      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)("  ParticleSystem %s, type: ", this->getName());
  {
      if (this->particleType == PARTICLE_MODEL)
        PRINT(0)("model");
      else if (this->particleType == PARTICLE_SPRITE)
        PRINT(0)("sprite");
      else if (this->particleType == PARTICLE_DOT)
        PRINT(0)("dot");
      else if (this->particleType == PARTICLE_SPARK)
        PRINT(0)("spark");

      PRINT(0)("\n");
  }

  PRINT(0)("  ParticleCount: %d, maximumCount: %d :: filled %d%%\n", this->count, 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);
    }
}