#include <vector>
#include <glbinding/gl/gl.h>

#define GLM_FORCE_RADIANS
#include <glm/glm.hpp>
#include <glm/gtc/matrix_transform.hpp>
#include <glm/gtc/type_ptr.hpp>
#include <glm/gtx/transform.hpp>

#include "shaders.hh"
#include "Object.hh"

using namespace gl;

Object::Object(VBOManager& vboManager, std::vector<objVertexAttribs> const& vas,
	       std::vector<uint16_t> indices, Program& prog)
  : _vboManager(vboManager), _prog(prog), _indices(std::move(indices)), _vaID(0)
{
  construct(vas);
}

Object::Object(VBOManager& vboManager, std::string const& filename,
	       Program& prog)
  : _vboManager(vboManager), _prog(prog), _vaID(0)
{
  auto tmp = readObject(filename);
  _indices = std::get<1>(tmp);
  construct(std::get<0>(tmp));
}

Object::~Object()
{
  glDeleteVertexArrays(1, &_vaID);
}

void Object::draw(glm::mat4 const& modelview, Program *override) const
{
  glBindVertexArray(_vaID);
  if (override)
    override->use();
  else
    _prog.use();
  glUniformMatrix4fv(_prog.getUniformLocation("model_matrix"), 1, GL_FALSE,
		     glm::value_ptr(modelview));
  glDrawElements(GL_TRIANGLES, _indices.size(), GL_UNSIGNED_SHORT,
		 _indices.data());
}

void Object::construct(std::vector<objVertexAttribs> const& vas)
{
  _vbo = _vboManager.alloc(sizeof(objVertexAttribs)*vas.size());
  glBindBuffer(GL_ARRAY_BUFFER, _vbo.getVBOId());
  glBufferSubData(GL_ARRAY_BUFFER, _vbo.getOfs(),
		  sizeof(objVertexAttribs)*vas.size(), (void*)vas.data());
  
  glGenVertexArrays(1, &_vaID);
  glBindVertexArray(_vaID);

  GLint al;
  if((al = _prog.getAttribLocation("vertex")) != -1) {
    glEnableVertexAttribArray(al);
    glVertexAttribPointer(al, 3, GL_FLOAT, GL_FALSE, sizeof(objVertexAttribs),
			  (void*)(_vbo.getOfs()+offsetof(objVertexAttribs, vertex)));
  }
  if((al = _prog.getAttribLocation("vertexTC")) != -1) {
    glEnableVertexAttribArray(al);
    glVertexAttribPointer(al, 2, GL_UNSIGNED_SHORT, GL_TRUE,
			  sizeof(objVertexAttribs),
			  (void*)(_vbo.getOfs()+offsetof(objVertexAttribs, texCoords)));
  }
  if((al = _prog.getAttribLocation("vertexNorm")) != -1) {
    glEnableVertexAttribArray(al);
    glVertexAttribPointer(al, 4, GL_INT_2_10_10_10_REV, GL_TRUE,
			  sizeof(objVertexAttribs),
			  (void*)(_vbo.getOfs()+offsetof(objVertexAttribs, normal)));
  }
}