#ifndef _ENGINE_H
#define _ENGINE_H

#include <SDL2/SDL.h>
#include <SDL2/SDL_image.h>
#include <iostream>
#include <string>
#include <unistd.h>
#include <limits.h>

class engine {
  public:
    SDL_Window *window;
    SDL_Renderer *renderer;
    SDL_Texture *font;
    SDL_Event event;

    int SCREEN_WIDTH;
    int SCREEN_HEIGHT;
    std::string title;
    

  public:
    engine(){}

    ~engine() {
      SDL_DestroyWindow(window);
      window = nullptr;

      SDL_DestroyRenderer(renderer);
      renderer = nullptr;

      SDL_DestroyTexture(font);
      font = nullptr;

      SDL_Quit();
    }

    bool Init(std::string title, int width, int height) {
      this->SCREEN_WIDTH = width;
      this->SCREEN_HEIGHT = height;
      this->title = title;

      if (SDL_Init(SDL_INIT_VIDEO) < 0){
        std::cout << "SDL_Init Error: " << SDL_GetError() << std::endl;
        return false;
      }

      window = SDL_CreateWindow(title.append(" | FPS: 0").c_str(), SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, width, height, SDL_WINDOW_SHOWN);
      if(window == nullptr) {
        std::cout << "SDL_CreateWindow Error: " << SDL_GetError() << std::endl;
        return false;
      }

      renderer = SDL_CreateRenderer(window, -1, SDL_RENDERER_ACCELERATED);
      if(renderer == nullptr) {
        std::cout << "SDL_CreateRenderer Error: " << SDL_GetError() << std::endl;
        return false;
      }

      return true;
    }

    void Run() {
      bool running = true;

      if(!OnUserCreate()){
        return;
      }

      unsigned long acumulatedTime = 0;
      unsigned long tick1 = SDL_GetTicks();
      unsigned long tick2 = SDL_GetTicks();
      unsigned long fpsAcumulator = 0;
      unsigned long fps = 0;

      while(running){
        tick2 = SDL_GetTicks();
        Uint32 elapsedTime = tick2 - tick1;
        tick1 = tick2;
        
        fpsAcumulator++;
        acumulatedTime += elapsedTime;
        if(acumulatedTime >= 1000) {
          acumulatedTime -= 1000;
          fps = fpsAcumulator;
          fpsAcumulator = 0;

          std::ostringstream title;
          title << this->title << " | FPS: " << fps;
          SDL_SetWindowTitle(window, title.str().c_str());
        }

        running = OnUserUpdate(elapsedTime);
      }
    }


  protected:
    virtual bool OnUserCreate() = 0;
    virtual bool OnUserUpdate(Uint32 elapsedTime) = 0;
};

#endif