#ifndef __OPENGLPLAYGROUND_SHADERS_HH__
#define __OPENGLPLAYGROUND_SHADERS_HH__

#include <string>
#include <unordered_map>

#include <glbinding/gl/types.h>

#include "common.hh"

static const gl::GLint ATTRIB_VERTEX_POS = 0;
static const gl::GLint ATTRIB_VERTEX_TC = 1;
static const gl::GLint ATTRIB_VERTEX_NORM = 2;
static const gl::GLint ATTRIB_VERTEX_COLOR = 3;

class ShaderException : public GLException {
public:
  ShaderException(std::string const& msg);
  
  //~ShaderException() {}

  std::string const& getMsg() const {return _msg;}
  
  std::string toString() const override {
    return "ShaderException: " + _msg;
  }
  
private:
  std::string _msg;
};

class Program;

class Shader {
public:
  Shader() : _shaderID(0) {
  }

protected:
  Shader(std::string const& program, gl::GLenum type);

public:
  virtual ~Shader();

  unsigned getID() const {
    return _shaderID;
  }
  
protected:
 
  unsigned int _shaderID;
};
  

class VertexShader : public Shader {
public:
  VertexShader(std::string const& program) : Shader(program, GL_VERTEX_SHADER) {
  }
};

class FragmentShader : public Shader {
public:
  FragmentShader(std::string const& program) : Shader(program, GL_FRAGMENT_SHADER) {
  }
};

class GeometryShader : public Shader {
public:
  GeometryShader(std::string const& program) : Shader(program, GL_GEOMETRY_SHADER) {
  }
};

class Program {
public:
  Program(VertexShader& vertex, FragmentShader& frag);

  Program(GeometryShader& geom, VertexShader& vertex, FragmentShader& frag);
  
  ~Program();

  void use() const;

  gl::GLint getUniformLocation(std::string const& name) const;

  // gl::GLint getAttribLocation(std::string const& name) const;
  
private:
  GeometryShader* _geom;
  VertexShader& _vertex;
  FragmentShader& _frag;
  unsigned _progID;

  mutable std::unordered_map<std::string, gl::GLint> _uniformLocCache, _attribLocCache;
};

#endif