#ifndef ENTITY_H
#define ENTITY_H

#include <GL/gl.h>

#include <vector>

#include "oct.h"

using namespace std;

typedef unsigned int soffs; // 32 bit
const soffs soffs_max = 1UL << 31;

#define GLFLOAT_MAX 1e30
#define GLFLOAT_MIN -1e30

struct sector {
  soffs x, y, z;
};

struct point {
  GLfloat x, y, z;

  point () { };
  point (GLfloat x, GLfloat y, GLfloat z) : x(x), y(y), z(z) { };
};

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

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 cross (const vec3 &a, const vec3 &b);
GLfloat dot (const vec3 &a, const vec3 &b);

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

struct box {
  point a, b;

  void reset ()
  {
    a = point (GLFLOAT_MAX, GLFLOAT_MAX, GLFLOAT_MAX);
    b = point (GLFLOAT_MIN, GLFLOAT_MIN, GLFLOAT_MIN);
  }

  void add (const box &o);
};

struct entity_base {
  struct entity_base *parent;
  vector<octant *> o;
  box bbox;

  virtual void update_bbox ();
  virtual void show (const sector &sec) { };
  void hide ();
  virtual void draw () = 0;
  virtual ~entity_base ()
  {
    hide ();
  };
};

struct entity_container : entity_base, protected vector<entity_base *> {
  void add (entity_base *e) { push_back (e); e->parent = this; }
  void update_bbox ();
  void show (const sector &sec);
  void draw ();
  ~entity_container ();
};

struct entity_filter : entity_base {
protected:
  entity_base *e;
public:

  void set (entity_base *e)
  {
    this->e = e;
    e->parent = this;
  }

  void remove ()
  {
    this->e->parent = 0;
    this->e = 0;
  }

  entity_base *content () { return e; };

  void update_bbox ();
  void show (const sector &sec);
  void draw ();
  ~entity_filter ();
};

struct entity : entity_filter {
  sector sec;

  void show (const sector &sec);
  void show ();
  void draw ();
};

struct entity_affine : entity_filter {
  //matrix m;
};

struct vertex1d {
  colour c; // colour
  point  p; // vertex
};

struct vertex2d {
  colour c; // colour
  point  p; // vertex
  vec3   n; // normal
  texc   t; // texture

  vertex2d () { };
  vertex2d (colour c, point p, vec3 n, texc t = texc()) : c(c), p(p), n(n), t(t) { };
};

template<GLenum type>
struct entity_opengl1d : entity_base, vector<vertex1d> {
  void update_bbox ();
  void show (const sector &sec);
  void draw ();
};

template<GLenum type>
struct entity_opengl2d : entity_base, vector<vertex2d> {
  void update_bbox ();
  void show (const sector &sec);
  void draw ();
};

typedef entity_opengl1d<GL_POINTS>         entity_points;
typedef entity_opengl1d<GL_LINES>          entity_lines;
typedef entity_opengl1d<GL_LINE_STRIP>     entity_line_strip;
typedef entity_opengl1d<GL_LINE_LOOP>      entity_line_loop;
typedef entity_opengl2d<GL_TRIANGLES>      entity_triangles;
typedef entity_opengl2d<GL_TRIANGLE_STRIP> entity_triangle_strip;
typedef entity_opengl2d<GL_TRIANGLE_FAN>   entity_triangle_fan;
typedef entity_opengl2d<GL_QUADS>          entity_quads;
typedef entity_opengl2d<GL_QUAD_STRIP>     entity_quad_strip;
typedef entity_opengl2d<GL_POLYGON>        entity_polygon;

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

struct draw_context {
  enum { DEPTH, AMBIENT, LIGHTED } mode;
  light *l;
};

struct view {
  point p;
  vec3 d, u;
  float fov;
  int w, h;

  void draw (const draw_context &c);
};

#endif