/*
   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: Patrick Boenzli
*/

#define DEBUG_SPECIAL_MODULE DEBUG_MODULE_GRAPHICS

#include "particle_emitter.h"

#include "particle_system.h"
#include "particle_engine.h"

#include "load_param.h"
#include "factory.h"
#include "debug.h"
#include "stdlibincl.h"

using namespace std;


CREATE_FACTORY(ParticleEmitter);

/**
 *  standard constructor
*/
ParticleEmitter::ParticleEmitter(const Vector& direction, float angle, float emissionRate,
                  float velocity)
{
  this->init();

  this->direction = direction;
  this->setSpread(angle);
  this->setEmissionRate(emissionRate);
  this->setEmissionVelocity(velocity);

  ParticleEngine::getInstance()->addEmitter(this);
}

/**
 *  constructs and loads a ParticleEmitter from a XML-element
 * @param root the XML-element to load from
*/
ParticleEmitter::ParticleEmitter(const TiXmlElement* root)
{
  this->init();

   if (root != NULL)
     this->loadParams(root);

   ParticleEngine::getInstance()->addEmitter(this);
}

/**
 *  standard destructor

   removes the EmitterSystem from the ParticleEngine
*/
ParticleEmitter::~ParticleEmitter ()
{
  ParticleEngine::getInstance()->removeEmitter(this);
}

/**
  \brief initializes default values of a ParitcleEmitter
*/
void ParticleEmitter::init()
{
  this->setClassID(CL_PARTICLE_EMITTER, "ParticleEmitter");

  this->type = PARTICLE_EMITTER_DEFAULT_TYPE;
  this->emitterSize = PARTICLE_EMITTER_DEFAULT_SIZE;
  this->setInheritSpeed(PARTICLE_EMITTER_DEFAULT_INHERIT_SPEED);
  this->setEmissionRate(PARTICLE_EMITTER_DEFAULT_EMISSION_RATE);
  this->setSize(PARTICLE_EMITTER_DEFAULT_SIZE);

  this->saveTime = 0.0;
}

/**
 *  loads a ParticleEmitter from a XML-element
 * @param root the XML-element to load from
*/
void ParticleEmitter::loadParams(const TiXmlElement* root)
{
  static_cast<PNode*>(this)->loadParams(root);

  LoadParamNEW(root, "type", this, ParticleEmitter, setType)
    .describe("What type of emitter is this [dot, plane, cube, sphere].");

  LoadParamNEW(root, "size", this, ParticleEmitter, setSize)
    .describe("How big the emitter is (no effect on dot-emitters)");

  LoadParamNEW(root, "rate", this, ParticleEmitter, setEmissionRate)
    .describe("How many particles should be emittet from this emitter");

  LoadParamNEW(root, "inherit-speed", this, ParticleEmitter, setInheritSpeed)
    .describe("the extent, the speed of the emitter has on the particles");

  LoadParamNEW(root, "emission-velocity", this, ParticleEmitter, setEmissionVelocity)
    .describe("How fast the particles are emittet (their initial speed)");

  LoadParamNEW(root, "emission-momentum", this, ParticleEmitter, setEmissionMomentum)
      .describe("How fast the particles rotation is at emissiontime (their initial momentum)");

  LoadParamNEW(root, "spread", this, ParticleEmitter, setSpread)
    .describe("The angle the particles are emitted from (angle, deviation)");


  LoadParamNEW(root, "emission-direction", this, ParticleEmitter, setDirection);
}

/**
 *  this start the emitter
*/
void ParticleEmitter::start() {}


/**
 *  this stops the emitter
*/
void ParticleEmitter::stop() {}





/**
 * @param type the new Type of this emitter
*/
void ParticleEmitter::setType(EMITTER_TYPE type)
{
  this->type = type;
}

/**
 *  sets the type of emitter
 * @param type the type as a const char*
   dot: EMITTER_DOT, plane: EMITTER_PLANE, cube: EMITTER_CUBE, sphere, EMITTER_SPHERE;
*/
void ParticleEmitter::setType(const char* type)
{
  if (!strcmp(type, "plane"))
    this->setType(EMITTER_PLANE);
  else if (!strcmp(type, "cube"))
    this->setType(EMITTER_CUBE);
  else if (!strcmp(type, "sphere"))
    this->setType(EMITTER_SPHERE);
  else
    this->setType(EMITTER_DOT);
}

const char* ParticleEmitter::getTypeC() const
{
  if (this->type == EMITTER_PLANE)
    return "EMITTER_PLANE";
  else if (this->type == EMITTER_CUBE)
    return "EMITTER_CUBE";
  else if (this->type == EMITTER_SPHERE)
    return "EMITTER_SPHERE";
  else
    return "EMITTER_DOT";
}

/**
 *  sets a new size to the emitter
*/
void ParticleEmitter::setSize(float emitterSize)
{
  if (emitterSize > 0.0)
    this->emitterSize = emitterSize;
  else
    emitterSize = 0.0;
}

/**
 *  set the emission rate
 * @param emissionRate: sets the number of particles emitted per second

   if you want to change the value of this variable during emission time (to make it more dynamic)
   you may want to use the animation class
*/
void ParticleEmitter::setEmissionRate(float emissionRate)
{
  if (emissionRate > 0.0)
    this->emissionRate = emissionRate;
  else
    this->emissionRate = 0.0;
}

/**
 *  how much of the speed from the ParticleEmitter should flow onto the ParticleSystem
 * @param value a Value between zero and one

   if you want to change the value of this variable during emission time (to make it more dynamic)
   you may want to use the animation class
*/
void ParticleEmitter::setInheritSpeed(float value)
{
  if (unlikely(value > 1.0))
    this->inheritSpeed = 1;
  else if (unlikely(value < 0.0))
    this->inheritSpeed = 0;
  else
    this->inheritSpeed = value;
}

/**
 *  set the angle of the emitter
 * @param angle around the direction in which there are particles to be emitted
 * @param randomAngle A random spread-angle, the +- randomness of this option

   if you want to change the value of this variable during emission time (to make it more dynamic)
   you may want to use the animation class
*/
void ParticleEmitter::setSpread(float angle, float randomAngle)
{
  this->angle = angle;
  this->randomAngle = randomAngle;
}

/**
 *  sets the initial velocity of all particles emitted
 * @param velocity The starting velocity of the emitted particles
 * @param randomVelocity A random starting velocity, the +- randomness of this option

   if you want to change the value of this variable during emission time (to make it more dynamic)
   you may want to use the animation class
*/
void ParticleEmitter::setEmissionVelocity(float velocity, float randomVelocity)
{
  this->velocity = velocity;
  this->randomVelocity = randomVelocity;
}

/**
 *  sets the initial Momentum of all particles emitted
 * @param momentum the new Momentum (just a float for being not too complicated).
 * @param randomMomentum variation from the given value.
 */
void ParticleEmitter::setEmissionMomentum(float momentum, float randomMomentum)
{
  this->momentum = momentum;
  this->momentumRandom = randomMomentum;
}

/**
 *  this set the time to life of a particle, after which it will die
 * @param dt: the time to live in seconds
 * @param system: the system into which to emitt

   if you want to change the value of this variable during emission time (to make it more dynamic)
   you may want to use the animation class
*/
void ParticleEmitter::tick(float dt, ParticleSystem* system)
{
  if (likely(dt > 0.0 && this->emissionRate > 0.0))
  {
    // saving the time (particles only partly emitted in this timestep)
    float count = (dt+this->saveTime) * this->emissionRate;
    this->saveTime = modff(count, &count) / this->emissionRate;
    PRINTF(5)("emitting %f particles, saving %f seconds for the next timestep\n", count, this->saveTime);

    if (likely(count > 0))
    {
      Vector inheritVelocity = this->getVelocity() * this->inheritSpeed;
      for (int i = 0; i < (int)count; i++)
      {
        Vector randDir = Vector(rand()-RAND_MAX/2, rand()-RAND_MAX/2, rand()-RAND_MAX/2);
        randDir.normalize();
        randDir = (this->getAbsDir()*Quaternion(angle + randomAngle *((float)rand()/RAND_MAX -.5), randDir)).apply(this->direction);
        Vector velocityV = randDir.getNormalized()*this->velocity + inheritVelocity;

        // this should spread the Particles evenly. if the Emitter is moved around quickly
        Vector equalSpread = this->getVelocity() * rand()/RAND_MAX * dt;
        Vector extension; // the Vector for different fields.

        if (this->type & EMITTER_PLANE)
        {
          extension = Vector(this->emitterSize * ((float)rand()/RAND_MAX -.5), 0, this->emitterSize * ((float)rand()/RAND_MAX - .5));
          extension = this->getAbsDir().apply(extension);
        }
        else if (this->type & EMITTER_CUBE)
        {
          extension = Vector((float)rand()/RAND_MAX -.5, (float)rand()/RAND_MAX -.5, (float)rand()/RAND_MAX -.5) * this->emitterSize;
        }


        // ROTATIONAL CALCULATION (this must not be done for all types of particles.)
        randDir = Vector(rand()-RAND_MAX/2, rand()-RAND_MAX/2, rand()-RAND_MAX/2);
        randDir.normalize();
        Quaternion orient = Quaternion(M_PI, randDir);
        Quaternion moment = Quaternion(this->momentum + this->momentumRandom, randDir);

        system->addParticle(this->getAbsCoor() + extension - equalSpread, velocityV, orient, moment);
      }
    }
  }
}

/**
 *  outputs some nice debug information
*/
void ParticleEmitter::debug() const
{
  PRINT(0)(" Emitter %s\n", this->getName());
  PRINT(0)("  EmissionRate: %f, Speed: %f, SpreadAngle: %f\n", this->getEmissionRate(), this->getEmissionVelocity(), this->getSpread());
  PRINT(0)("  Size %f, Type: %s\n", this->getSize(), this->getTypeC());
}