#include <glbinding/gl/gl.h>

#include "shaders.hh"

using namespace gl;

ShaderException::ShaderException(std::string const& msg)
  : GLException(glGetError()), _msg(msg)
{
}

Shader::Shader(std::string const& program, GLenum type)
  : _shaderID(glCreateShader(type))
{
  const char* const arr[] = {program.c_str()};
  glShaderSource(_shaderID, 1, arr, NULL);
  glCompileShader(_shaderID);
    
  int state;
  glGetShaderiv(_shaderID, GL_COMPILE_STATUS, &state);
    
  if (state == 0) {
    int logLength;
    glGetShaderiv(_shaderID, GL_INFO_LOG_LENGTH, &logLength);
      
    char *log = new char[logLength];
    glGetShaderInfoLog(_shaderID, logLength, NULL, log);
    std::string msg(log);
    delete[] log;
      
    glDeleteShader(_shaderID);
      
    throw ShaderException(msg);
  }
}

Shader::~Shader()
{
  glDeleteShader(_shaderID);
}

Program::Program(VertexShader& vertex, FragmentShader& frag)
  : _geom(nullptr), _vertex(vertex), _frag(frag), _progID(glCreateProgram())
{  
  glAttachShader(_progID, _vertex.getID());
  glAttachShader(_progID, _frag.getID());

  glLinkProgram(_progID);
    
  int state;
  glGetProgramiv(_progID, GL_LINK_STATUS, &state);
    
  if (state == 0) {
    int logLength;
    glGetProgramiv(_progID, GL_INFO_LOG_LENGTH, &logLength);
      
    char *log = new char[logLength];
    glGetProgramInfoLog(_progID, logLength, NULL, log);
    std::string msg(log);
    delete[] log;
      
    glDeleteProgram(_progID);
      
    throw ShaderException(msg);
  }

  glDetachShader(_progID, _vertex.getID());
  glDetachShader(_progID, _frag.getID());
}

Program::Program(GeometryShader& geom, VertexShader& vertex, FragmentShader& frag)
  : _geom(&geom), _vertex(vertex), _frag(frag), _progID(glCreateProgram())
{
  glAttachShader(_progID, _geom->getID());
  glAttachShader(_progID, _vertex.getID());
  glAttachShader(_progID, _frag.getID());

  glLinkProgram(_progID);
    
  int state;
  glGetProgramiv(_progID, GL_LINK_STATUS, &state);
    
  if (!state) {
    int logLength;
    glGetProgramiv(_progID, GL_INFO_LOG_LENGTH, &logLength);
      
    char *log = new char[logLength];
    glGetProgramInfoLog(_progID, logLength, NULL, log);
    std::string msg(log);
    delete[] log;
      
    glDeleteProgram(_progID);
      
    throw ShaderException(msg);
  }

  glDetachShader(_progID, _geom->getID());
  glDetachShader(_progID, _vertex.getID());
  glDetachShader(_progID, _frag.getID());
}

Program::~Program()
{
  glDeleteProgram(_progID);
}

void Program::use() const
{
  glUseProgram(_progID);
}

GLint Program::getUniformLocation(std::string const& name) const
{
  auto search = _uniformLocCache.find(name);
  if (search != _uniformLocCache.end())
    return search->second;
  
  GLint ret = glGetUniformLocation(_progID, name.c_str());
  if (ret != -1)
    _uniformLocCache.emplace(name, ret);
  return ret;
}

// GLint Program::getAttribLocation(std::string const& name) const
// {
//   auto search = _attribLocCache.find(name);
//   if (search != _attribLocCache.end())
//     return search->second;
  
//   GLint ret = glGetAttribLocation(_progID, name.c_str());
//   if (ret != -1)
//     _attribLocCache.emplace(name, ret);
//   return ret;
// }