/*! 
    \file particle_system.h

*/

#ifndef _PARTICLE_SYSTEM_H
#define _PARTICLE_SYSTEM_H

#include "base_object.h"
#include "physics_interface.h"

#include "glincl.h"
#include "vector.h"

#define PARTICLE_DOT_MASK           0x000001
#define PARTICLE_SPARK_MASK         0x000010
#define PARTICLE_SPRITE_MASK        0x000100
#define PARTICLE_MODEL_MASK         0x001000
#define PARTICLE_WORDL_ENTITY_MASK  0x010000
#define PARTICLE_MULTI_MASK         0x100000

//! An enumerator for the different types of particles.
typedef enum PARTICLE_TYPE {PARTICLE_DOT = PARTICLE_DOT_MASK,
			    PARTICLE_SPARK = PARTICLE_SPARK_MASK,
			    PARTICLE_SPRITE = PARTICLE_SPRITE_MASK,
			    PARTICLE_MULTI_SPRITE = PARTICLE_SPRITE_MASK | PARTICLE_MULTI_MASK,
			    PARTICLE_MODEL = PARTICLE_MODEL_MASK,
			    PARTICLE_MULTI_MODE = PARTICLE_MODEL_MASK | PARTICLE_MULTI_MASK};

#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;
class Field;

//! A struct for one Particle
typedef struct Particle
{
  float lifeTime;             //!< The time this particle has to live.
  float lifeCycle;            //!< The fraction of time passed. (in percentage of its lifeTime)

  Vector position;            //!< The current position of this particle.
  Vector velocity;            //!< The current velocity of this particle.
  Vector extForce;            //!< The external Force that influences 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.

  GLfloat color [4];          //!< A Color for the particles.

  PARTICLE_TYPE type;

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

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

 public:
  ParticleSystem(unsigned int maxCount = PARTICLE_DEFAULT_MAX_COUNT,
		 PARTICLE_TYPE type = PARTICLE_DEFAULT_TYPE);
  virtual ~ParticleSystem();
  void setName(const char* name);
  const char* getName(void) const;

  void setType(PARTICLE_TYPE particleType, int count = 0);
  void setMaterial(Material* material);
  void setInheritSpeed(float value);
  void setLifeSpan(float lifeSpan, float randomLifeSpan = 0.0);
  void setRadius(float startRadius, float endRadius,
		 float randomStartRadius = 0.0, float randomEndRadius = 0.0);
  void setConserve(float conserve);
  void setMass(float mass, float randomMass = 0.0);

  void setColor(GLfloat br, GLfloat bg, GLfloat bb, GLfloat ba,
		GLfloat mr, GLfloat mg, GLfloat mb, GLfloat ma,
		GLfloat er, GLfloat eg, GLfloat eb, GLfloat ea);

  /** \returns the Type of the particles */
  inline PARTICLE_TYPE getType(void) const { return this->particleType; };
  /** \returns the Material that lies on this particles */
  inline const Material* getMaterial(void) const { return this->material; };
  /** \returns the inherit-speed-factor */
  inline float getInheritSpeed(void) const { return this->inheritSpeed; };
  /** \returns the lifespan of the particles */
  inline float getLifeSpan(void) const { return this->lifeSpan; };
  /** \returns the starting-radius of the particles */
  inline float getStartRadius(void) const { return this->startRadius; };
  /** \returns the end-radius of the particles */
  inline float getEndRadius(void) const { return this->endRadius; };
  /** \returns the conserve-factor of the particles */
  inline float getConserve(void) const { return this->conserve; };
  /** \returns the initial mass of the particles */
  inline float getMass(void) const { return this->initialMass; };

  virtual void applyField(Field* field, float dt);

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

  void debug(void);

 private:
  char* name;                // the Name of the Particle System

  float conserve;            //!< How much energy gets conserved to the next Tick.
  float lifeSpan;            //!< Initial lifetime of a Particle.
  float randomLifeSpan;      //!< A random value for the Lifespan (around the initial lifetime)
  float startRadius;         //!< The beginning Radius of the Particle
  float endRadius;           //!< The end Radius of the Particle
  float randomStartRadius;   //!< The Random start Radius (begin + rand*randomValue)
  float randomEndRadius;     //!< Random end value
  float initialMass;         //!< The initial Mass of the Particle
  float randomInitialMass;   //!< The random initial Mass of the Particle
  float inheritSpeed;        //!< How much speed the particle inherits from the Emitters speed \todo move this to the emitter

  GLfloat startColor[4];     //!< Color of the Particle at the beginning
  GLfloat midColor[4];       //!< Color of the Particle at the middle of its lifeSpan
  GLfloat endColor[4];       //!< Color of the Particle at the end of its lifeSpan

  // 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.
  Particle* deadList;        //!< A list of dead Particles in the System.

  GLuint* glID;              //!< A List of different gl-List-ID's
  GLuint dialectCount;       //!< How many different types of particles are there in the Particle System

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

#endif /* _PARTICLE_SYSTEM_H */