#include "engine.h"
#include <cstdlib>
#include <iostream>
#include <vector>

djalim::OpenGlEngine::OpenGlEngine(const char* title, int width, int height) {
  // initialize GLFW
  if (!glfwInit()) {
    std::cerr << "Failed to initialize GLFW" << std::endl;
    exit(1);
  }

  loadHints();

  this->window = glfwCreateWindow(width, height, title, NULL, NULL);
  if (!this->window) {
    std::cerr << "Failed to create GLFW window" << std::endl;
    glfwTerminate();
    exit(1);
  }

  glfwMakeContextCurrent(this->window);

  // initialize GLEW
  glewExperimental = GL_TRUE;
  if (glewInit() != GLEW_OK) {
    std::cerr << "Failed to initialize GLEW" << std::endl;
    exit(1);
  }

  loadCallbacks();

  bool loaded = shaderProgram.loadShaders("../assets/shaders/vertex.glsl", "../assets/shaders/fragment.glsl");
  if (!loaded) {
    std::cerr << "Failed to load shaders correctly" << std::endl;
    exit(1);
  }

  onCreate();

}


void djalim::OpenGlEngine::createObject(std::string name, std::string textures, std::vector<float>& vertices){
  
  objects[name];

  bool textureLoaded = objects[name].texture.loadTexture(textures);
  
  if (!textureLoaded) {
    std::cerr << "Failed to load " << name << " texture!" << std::endl;
    exit(1);
  }

  //glGenVertexArrays(1, &VAO);
  glGenVertexArrays(1, &(objects[name].VAO));

  //glGenBuffers(1, &VBO);
  glGenBuffers(1, &(objects[name].VBO));
  
  //glBindVertexArray(VAO);
  glBindVertexArray(objects[name].VAO);


  //glBindBuffer(GL_ARRAY_BUFFER, VBO);
  glBindBuffer(GL_ARRAY_BUFFER, objects[name].VBO);


  std::cout << "Loading 3D objects with "<< vertices.size() << " vertices"<< std::endl;
  glBufferData(GL_ARRAY_BUFFER, sizeof(float)*vertices.size(), vertices.data(), GL_STATIC_DRAW);
  
  // Attribut de position
  glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 5 * sizeof(float), (void*)0);
  glEnableVertexAttribArray(0);
  // Attribut de coordonnée de texture
  glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, 5 * sizeof(float), (void*)(3 * sizeof(float)));
  glEnableVertexAttribArray(1);
}

djalim::OpenGlEngine::~OpenGlEngine() {
  onDestroy();
  glfwDestroyWindow(window);
  glfwTerminate();
}

void djalim::OpenGlEngine::start(){
  // Main loop

  double currentSeconds;
  while (!glfwWindowShouldClose(this->window)) {

    currentSeconds = glfwGetTime();
    elapsedSeconds = currentSeconds-previousSeconds;
    previousSeconds = currentSeconds;

    glfwPollEvents();
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    //glClearColor(0, 0.5, 0.5, 1.0f);

    onUpdate();

    glfwSwapBuffers(this->window);

  }
}