#ifndef MATERIAL_H
#define MATERIAL_H

#include <vector>
#include <string>
#include <sstream>

#include "opengl.h"

#include "util.h"

namespace shader {

  using namespace std;

  const int NAMELEN = 16;

  class refcounted
  {
    template<class data> friend class ref;
    int refcnt;
    void refcnt_inc () { refcnt++; }
    void refcnt_dec () { if (!--refcnt) delete this; };
  public:
    refcounted () : refcnt(0) { }
    virtual ~refcounted ();
  };

  template<class data>
  class ref
  {
    data *p;

  public:
    ref (const data &d)
    {
      d.refcnt_inc ();
      p = &v;
    }

    ref (const ref<data> &r)
    {
      r.refcnt_inc ();
      p = r.p;
    }

    ref &operator =(const data &d)
    {
      d.refcnt_inc ();
      p->refcnt_dec ();
      p = &r;
      return *this;
    }

    ref &operator =(const ref r)
    {
      return *this = *r->p;
    }

    ref operator &() { return *this; }
    const ref operator &() const { return *this; }

    ref *operator ->() { return p; }
    const ref *operator ->() const { return p; }

    bool operator ==(const ref b)
    {
      return p == b->p;
    }
  };

  typedef ref<struct var_i> var;
  typedef ref<struct updateable_i> updateable;

  struct shader_builder
  {
    struct shader_program *prog;
    vector<updateable> refs; // uniform parameters
    vector<var> inputs; // varying inputs
    vector<var> outputs; // varying outputs
    vector<var> samplers; // textures

    ostringstream fragment;

    template<typename type>
    shader_builder &operator <<(const type &t)
    {
      fragment << t;
      return *this;
    }
  };

  struct fragment
  {
    virtual void build (shader_builder &b) = 0;
  };

  struct var_i : fragment
  {
    static int next_name;

    CGparameter param;
    int name;

    void build (shader_builder &b);
    void build_decl (shader_builder &b);

    var_i (CGtype cgtype);
    ~var_i ();
  };

  inline ostringstream &operator <<(ostringstream &os, const var_i &v)
  {
    os << ' ' << v.name << ' ';
    return os;
  }

  struct updateable_i : var_i
  {
    virtual void update () = 0;

    updateable_i (CGtype cgtype) : var_i (cgtype) { }
  };

  template<int dimension, typename gltype, CGtype cgtype, void (*update)(CGparameter, const gltype *)>
  struct uniform_i : updateable_i
  {
    gltype data[dimension];
    bool dirty;

    void update ()
    {
      if (dirty)
        {
          update (param, data);
          dirty = false;
        }
    }

    uniform_i () : var_i (cgtype) { }
  };

  template<int dimension, void (*update)(CGparameter, const GLfloat *)>
  struct uniform_f_i : uniform_i<dimension, GLfloat, CG_FLOAT, update>
  {
  };

  struct uniform_1f_i : uniform_f_i<1, cgGLSetParameter1fv> {
    void operator =(GLfloat v)
    {
      data[0] = v;
      dirty = true;
    }
  };

  struct uniform_2f_i : uniform_f_i<2, cgGLSetParameter2fv> { };

  struct uniform_3f_i : uniform_f_i<3, cgGLSetParameter3fv> {
    void operator =(const vec3 &v)
    {
      data[0] = v.x;
      data[1] = v.y;
      data[2] = v.z;
      dirty = true;
    }
  };

  struct uniform_4f_i : uniform_f_i<4, cgGLSetParameter4fv> {
    void operator =(const gl::matrix &m)
    {
      memcpy (data, m.data, 16 * sizeof (GLfloat));
      dirty = true;
    }
  };

  struct uniform_matrix_f_i : uniform_f_i<16, cgGLSetMatrixParameterfc> { };

  typedef ref<uniform_1f_i> uniform_1f;
  typedef ref<uniform_2f_i> uniform_2f;
  typedef ref<uniform_3f_i> uniform_3f;
  typedef ref<uniform_4f_i> uniform_4f;
  typedef ref<uniform_matrix_f_i> uniform_matrix_f;

  template<int dimension, GLenum gltype, CGtype cgtype>
  struct varying_i : var_i
  {
    char binding[16];

    varying_i (const char *binding);

    void set (GLsizei stride, GLvoid *ptr)
    {
      cgGLSetParameterPointer (param, dimension, gltype, stride, ptr);
    }
  };

  template<int dimension>
  struct varying_f_i : varying_i<dimension, GL_FLOAT, CG_FLOAT>
  {
    varying_f_i (const char *binding) : varying_i<dimension, GL_FLOAT, CG_FLOAT> (binding) { }

    void set (const gl::vertex_buffer_object &vb, GLint offset)
    {
      varying_i<dimension, GL_FLOAT, CG_FLOAT>::set (gl::format_stride (vb.format), (GLvoid *)(long)offset);
    }
  };

  struct varying_1f_i : varying_f_i<1>
  {
    varying_1f_i (const char *binding) : varying_f_i<1> (binding) { }
  };

  struct varying_2f_i : varying_f_i<2>
  {
    varying_2f_i (const char *binding) : varying_f_i<2> (binding) { }

    void set_t (const gl::vertex_buffer_object &vb)
    {
      set (vb, gl::format_offset_t (vb.format));
    }
  };

  struct varying_3f_i : varying_f_i<3>
  {
    varying_3f_i (const char *binding) : varying_f_i<3> (binding) { }

    void set_p (const gl::vertex_buffer_object &vb)
    {
      set (vb, gl::format_offset_p (vb.format));
    }

    void set_n (const gl::vertex_buffer_object &vb)
    {
      set (vb, gl::format_offset_n (vb.format));
    }
  };

  struct varying_4f_i : varying_f_i<4>
  {
    varying_4f_i (const char *binding) : varying_f_i<4> (binding) { }
  };

  typedef ref<varying_1f_i> varying_1f;
  typedef ref<varying_2f_i> varying_2f;
  typedef ref<varying_3f_i> varying_3f;
  typedef ref<varying_4f_i> varying_4f;

  extern varying_3f_i position_3f;
  extern varying_3f_i normal_3f;
  extern varying_3f_i color0_3f;
  extern varying_3f_i color1_3f;
  extern varying_2f_i texcoord0_2f;
  extern varying_2f_i texcoord1_2f;
  extern varying_2f_i texcoord2_2f;
  extern varying_2f_i texcoord3_2f;
  extern varying_2f_i texcoord4_2f;
  extern varying_2f_i texcoord5_2f;
  extern varying_2f_i texcoord6_2f;
  extern varying_2f_i texcoord7_2f;
  extern varying_1f_i attr6_1f, attr7_1f;
  extern varying_2f_i attr6_2f, attr7_2f;
  extern varying_3f_i attr6_3f, attr7_3f;

  template<CGtype cgtype>
  struct sampler_i : var_i
  {
    sampler_i () : var_i (cgtype) { }
  };

  struct shader_program
  {
  };
}

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

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

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



struct material
{
  virtual void begin () = 0;
  virtual void end () = 0;
  virtual ~material ();
};

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

  void begin ();
  void end ();

  simple_material () 
  : diffuse(1, 0, 1, 1)
  , specular(1, 0, 1, 1)
  , emission(1, 0, 1, 1)
  , shininess(1.)
  {
  }
};

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

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

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

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

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

extern CGcontext cgc;

struct shader 
{
   CGprogram vsh, fsh;
   CGparameter lightpos;
   // mv, mvp
   CGprofile vsh_profile, fsh_profile;
   CGparameter g_Texture; // the texture parameter

   void check_cg_error (void)
   {
     CGerror err = cgGetError ();

     if (err != CG_NO_ERROR)
       {
         printf("CG error: %s\n", cgGetErrorString (err));
         exit(1);
       }
   }
   shader (const char *vshp, const char *fshp)
   {
     vsh_profile = CG_PROFILE_ARBVP1;
     //if (cgGLIsProfileSupported (CG_PROFILE_VP30)) vsh_profile = CG_PROFILE_VP30;
     //if (cgGLIsProfileSupported (CG_PROFILE_VP40)) vsh_profile = CG_PROFILE_VP40;
     fsh_profile = CG_PROFILE_ARBFP1;
     //if (cgGLIsProfileSupported (CG_PROFILE_FP30)) fsh_profile = CG_PROFILE_FP30;
     //if (cgGLIsProfileSupported (CG_PROFILE_FP40)) fsh_profile = CG_PROFILE_FP40;

     vsh = cgCreateProgramFromFile (cgc, CG_SOURCE, vshp, vsh_profile, 0, 0);
     check_cg_error ();
     cgGLLoadProgram (vsh);
     check_cg_error ();

     fsh = cgCreateProgramFromFile (cgc, CG_SOURCE, fshp, fsh_profile, 0, 0);
     check_cg_error ();
     cgGLLoadProgram (fsh);
     check_cg_error ();

     cgGLBindProgram (vsh);
     cgGLBindProgram (fsh);

    // mv = cgGetNamedParameter (vsh, "WorldProj");
    // mvp = cgGetNamedParameter (vsh, "WorldViewProj");
     //lightpos = cgGetNamedParameter (vsh, "LightPos");
     //cgGLSetParameter4f (lightpos, 10, 10, 0, 1); //camera.p.x, camera.p.y, camera.p.z, 1);

     check_cg_error ();
   }
};

struct osama_material : material, texture, shader {
  osama_material () 
  : shader ("vsh.cg", "fsh.cg"), texture ("textures/osama.jpg") 
  {
     g_Texture = cgGetNamedParameter(fsh, "Texture"); // the texture cg-warper ;)
     cgGLSetTextureParameter(g_Texture, texture_pxls); // Bind the texture number 999 to g_Texture
  }

  void begin ();
  void end ();

};

void init_shaders ();
#endif