/*! 
    \file particle_system.h

*/

#ifndef _PARTICLE_SYSTEM_H
#define _PARTICLE_SYSTEM_H

#include "base_object.h"
#include "vector.h"

//! An enumerator for the different types of particles.
typedef enum PARTICLE_TYPE {PARTICLE_DOT,
			    PARTICLE_SPRITE,
			    PARTICLE_MULTI_SPRITE,
			    PARTICLE_OBJECT,
			    PARTICLE_MULTI_OBJECT,
			    PARTICLE_PRIMITIVE};

#define PARTICLE_DEFAULT_MAX_COUNT 200         //!< a default count of particles in the system.
#define PARTICLE_DEFAULT_TYPE  PARTICLE_SPRITE //!< A default type of the system.

// FORWARD DEFINITION
class Material;
class ParticleEmitter;


//! A struct for one Particle
typedef struct Particle
{
  float timeToLive;           //!< The time this particle lives from NOW on.
  Vector position;            //!< The current position of this particle.
  Vector velocity;            //!< The current velocity of this particle.
  Quaternion rotation;        //!< The current rotation of this particle.
  float mass;                 //!< The mass of this particle.
  float radius;               //!< The current size of this particle.
  float radiusIt;             //!< The difference of the Size per second.

  Particle* next;             //!< pointer to the next particle in the List. (NULL if no preceding one)
};

//! A class to handle particle Systems
class ParticleSystem : public BaseObject {
  friend class ParticleEmitter;

 public:
  ParticleSystem(unsigned int maxCount = PARTICLE_DEFAULT_MAX_COUNT, PARTICLE_TYPE type = PARTICLE_DEFAULT_TYPE);
  virtual ~ParticleSystem();

  void setMaterial(Material* material);
  void setInheritSpeed(float value);
  void setLifeSpan(float lifeSpan, float randomLifeSpan = 0.0);
  void setRadius(float startRadius, float endRadius, float randomRadius = 0.0);
  void setConserve(float conserve);
  void setMass(float mass, float randomMass);

  void tick(float dt);
  void draw(void);

 private:
  float conserve;            //!< How much energy gets conserved to the next Tick.
  float lifeSpan;            //!< Initial lifetime of a Particle.
  float randomLifeSpan;
  float startRadius;
  float endRadius;
  float randomRadius;
  float initialMass;
  float randomInitialMass;
  float inheritSpeed;

  // particles
  int maxCount;              //!< The maximum count of Particles.
  int count;                 //!< The current count of Particles.
  PARTICLE_TYPE particleType;//!< A type for all the Particles
  Material* material;        //!< A Material for all the Particles.
  Particle* particles;       //!< A list of particles of this System.


  void addParticle(Vector position, Vector velocity, unsigned int data = 0);
  
};

#endif /* _PARTICLE_SYSTEM_H */