#ifndef UTIL_H
#define UTIL_H

#include <SDL/SDL.h>
#include <SDL/SDL_image.h>
#include <cmath>
#include <cfloat>
#include <vector>
#include <string>

#include <Cg/cg.h>
#include <Cg/cgGL.h>

using namespace std;

extern CGcontext cgc;
extern CGprogram vsh;
extern CGprogram fsh;
extern CGparameter mv, mvp, lightpos;
extern CGprofile vsh_profile, fsh_profile;

#include <GL/gl.h>

typedef int soffs; // 32 bit
typedef unsigned int uoffs;
#define OFFS_BITS 31
#define SOFFS_MIN (soffs)-(1 << (OFFS_BITS - 2))
#define SOFFS_MAX (soffs)+(1 << (OFFS_BITS - 2))
#define MAXEXTENT (1UL << (OFFS_BITS - 1))

#define GLFLOAT_MAX 1e30
#define GLFLOAT_MIN -1e30

struct vec3 {
  GLfloat x, y, z;
  vec3 () { };
  vec3 (GLfloat x, GLfloat y, GLfloat z) : x(x), y(y), z(z) { };

  const vec3 operator -() const
  { return vec3 (-x, -y, -z); }
};

const vec3 normalize (const vec3 &v);
const vec3 cross (const vec3 &a, const vec3 &b);

inline const vec3 operator *(const vec3 &a, GLfloat s)
{
  return vec3 (a.x * s, a.y * s, a.z * s);
}

inline const vec3 operator +(const vec3 &a, const vec3 &b)
{
  return vec3 (a.x + b.x, a.y + b.y, a.z + b.z);
}

inline const vec3 operator -(const vec3 &a, const vec3 &b)
{
  return vec3 (a.x - b.x, a.y - b.y, a.z - b.z);
}

inline GLfloat dot (const vec3 &a, const vec3 &b)
{
  return a.x * b.x + a.y * b.y + a.z * b.z;
}

inline const GLfloat abs (const vec3 &v)
{
  return sqrtf (dot (v, v));
}

struct matrix {
  GLfloat data[4][4];

  const GLfloat operator ()(int i, int j) const { return data[j][i]; };
  GLfloat &operator ()(int i, int j) { return data[j][i]; };

  void diagonal (GLfloat v);
  void clear () { diagonal (0.); };
  void identity () { diagonal (1.); };

  void print (); // ugly

  static const matrix translation (const vec3 &v);
  static const matrix rotation (GLfloat degrees, const vec3 &axis);

  matrix () { };
  matrix (GLfloat diag) { diagonal (diag); };
};

const matrix operator *(const matrix &a, const matrix &b);
const vec3 operator *(const matrix &a, const vec3 &v);

typedef vec3 point;

// a generic plane
struct plane {
  vec3 n;
  GLfloat d;

  GLfloat distance (const point &p) const
  {
    return dot (n, p) + d;
  }

  plane () { };
  plane (GLfloat a, GLfloat b, GLfloat c, GLfloat d);
};

struct sector {
  soffs x, y, z;

  sector (soffs x = 0, soffs y = 0, soffs z = 0) : x(x), y(y), z(z) { };

  void offset (int subindex, uoffs extent)
  {
    if (subindex & 1) x += extent;
    if (subindex & 2) y += extent;
    if (subindex & 4) z += extent;
  }
};

inline const sector operator +(const sector &a, const sector &b)
{
  return sector (a.x + b.x, a.y + b.y, a.z + b.z);
}

inline const sector operator -(const sector &a, const sector &b)
{
  return sector (a.x - b.x, a.y - b.y, a.z - b.z);
}

inline const sector translate (const sector &p, const sector &src, const sector &dst)
{
  return p + (dst - src);
}

void renormalize (sector &s, point &p);

struct colour {
  GLfloat r, g, b, a;
  colour (GLfloat r = 1., GLfloat g = 1., GLfloat b = 1., GLfloat a = 1.) : r(r), g(g), b(b), a(a) { };
};

struct texc {
  GLfloat s, t;
  texc () { };
  texc (GLfloat s, GLfloat t) : s(s), t(t) { };
};

struct box {
  point a, b;

  box() { };

  void reset ()
  {
    a = point ( FLT_MAX,  FLT_MAX,  FLT_MAX);
    b = point (-FLT_MAX, -FLT_MAX, -FLT_MAX);
  }

  void add (const box &o);
  void add (const point &p);
};

struct light {
  point p;
  colour c;
  GLfloat intensity;
  GLfloat radius;
};

struct material {
  colour diffuse, specular, emission;
  GLfloat shininess;

  material () 
  { 
    diffuse   = colour (1, 0, 1, 1);
    specular  = colour (1, 0, 1, 1);
    emission  = colour (1, 0, 1, 1);
    shininess = 1;
  }
};

struct entity;
struct geometry;
struct view;

extern struct timer {
  static double now;
  static double diff;

  static void frame ();
  timer ();
} timer;

/*
#define MAX_EVENT_TYPES 10
enum event_type { TIMER_EV };
struct event {
   event_type type;
};

typedef callback1<void, event&> event_cb;

class skedjuhlar {

   public:
// only 10 types for now
   private:
      vector <list<event_cb> > event_lists;
   
   public:
      skedjuhlar () {
         event_lists.resize (MAX_EVENT_TYPES, list<event_cb>());
      }
      
      void register_event_cb (const event_type &t, const event_cb &e) {
         event_lists[t].push_back (e);
      };
      void send_event (event &e) {
         list<event_cb> &l = event_lists[e.type];
         for (list<event_cb>::iterator it = l.begin (); it != l.end (); it++) {
            (*it)(e);
         }
      };
      void check_events () {
         while (!events.empty ()) {
            event &e = events.pop_front ();
            list<event_cb> &l = event_lists[e->name];
            for (list<event_cb>::iterator it = l.begin (); it !+ l.end (); it++) {
               (*it)(e);
            }
            delete e; // ugly slow? hai hai..... 183G
         }
      }
};

extern skedjuhlar main_scheduler;
*/

GLuint SDL_GL_LoadTexture (SDL_Surface * surface, GLfloat * texcoord);

inline int power_of_two (int input)
{
  int value = 1;

  while (value < input)
    {
      value <<= 1;
    }
  return value;
}

struct TextureExecption { 
  TextureExecption (string s) : msg(s) { }
  string msg; 
};

struct Texture {
  SDL_Surface *image;
  GLuint texture;
  GLfloat texcoord[4];

public:

  Texture(const char *f)
  {
    image = IMG_Load (f);

    if (!image) 
      throw (TextureExecption ("Couldn't load " + (string) f + ": " + (string) IMG_GetError ()));

    texture = SDL_GL_LoadTexture (image, (GLfloat*)&texcoord);
    if (texture == 0) 
      throw (TextureExecption ("Couldn't make GL Texture, failed to create new RGB SWSurface"));
  }
};

#endif