#include <SDL.h>
#include <SDL_image.h>
#include <SDL_ttf.h>
#include <stdlib.h>
#include <stdio.h>
#include <stdint.h>
#include <errno.h>
#include <string.h>
#include <assert.h>
#include "kiss.h"

char *title = "SDL 26 - Motion";
SDL_Window *window;
SDL_Renderer *renderer;
SDL_Texture *obj_texture;

enum { obj_vel = 10 };

struct obj
{
   int x, y;
   int vx, vy;
};

int
init_sdl(void)
{
   int status = -1;

   SDL_INIT(SDL_INIT_VIDEO);
   IMG_INIT(IMG_INIT_PNG);
   window = SDL_CREATEWINDOW(title, 50, 50, 800, 600, 0);
   renderer = SDL_CREATERENDERER(window, -1, SDL_RENDERER_ACCELERATED | SDL_RENDERER_PRESENTVSYNC);
   status = 0;
error:
   return status;
}

#define INIT_SDL(...) SDL_ZERO(init_sdl, __VA_ARGS__)

void
close_sdl(void)
{
   SDL_DestroyRenderer(renderer);
   SDL_DestroyWindow(window);
   IMG_Quit();
   SDL_Quit();
}

SDL_Texture *
load_texture(char *path)
{
   SDL_Texture *ret = NULL;
   SDL_Texture *texture = NULL;
   SDL_Surface *surface = NULL;
   surface = IMG_LOAD(path);
   SDL_SETCOLORKEY(surface, SDL_TRUE, SDL_MapRGB(surface->format, 0x00, 0xFF, 0xFF));
   texture = SDL_CREATETEXTUREFROMSURFACE(renderer, surface);
   SDL_SETTEXTUREBLENDMODE(texture, SDL_BLENDMODE_BLEND);
   ret = texture;
error:
   if (!ret)
     SDL_DestroyTexture(texture);
   SDL_FreeSurface(surface);
   return ret;
}

#define LOAD_TEXTURE(...) SDL_CHK(load_texture, __VA_ARGS__)

void
obj_handle_event(struct obj *obj, SDL_Event *e)
{
   if (e->type == SDL_KEYDOWN && e->key.repeat == 0)
     {
        switch (e->key.keysym.sym)
          {
           case SDLK_UP: obj->vy -= obj_vel; break;

           case SDLK_DOWN: obj->vy += obj_vel; break;

           case SDLK_LEFT: obj->vx -= obj_vel; break;

           case SDLK_RIGHT: obj->vx += obj_vel; break;
          }
     }
   else if (e->type == SDL_KEYUP && e->key.repeat == 0)
     {
        switch (e->key.keysym.sym)
          {
           case SDLK_UP: obj->vy += obj_vel; break;

           case SDLK_DOWN: obj->vy -= obj_vel; break;

           case SDLK_LEFT: obj->vx += obj_vel; break;

           case SDLK_RIGHT: obj->vx -= obj_vel; break;
          }
     }
}

int
obj_move(struct obj *obj)
{
   int status = -1;
   int w, h;
   int tw, th;

   SDL_GetWindowSize(window, &w, &h);
   SDL_QUERYTEXTURE(obj_texture, NULL, NULL, &tw, &th);

   obj->x += obj->vx;
   obj->y += obj->vy;

   if (obj->x < 0 || obj->x + tw > w)
     obj->x -= obj->vx;

   if (obj->y < 0 || obj->y + th > h)
     obj->y -= obj->vy;

   status = 0;
error:
   return status;
}

#define OBJ_MOVE(...) SDL_ZERO(obj_move, __VA_ARGS__)

int
obj_draw(struct obj *obj)
{
   int status = -1;
   int w, h;
   int tw, th;
   SDL_Rect target;

   SDL_GetWindowSize(window, &w, &h);
   SDL_QUERYTEXTURE(obj_texture, NULL, NULL, &tw, &th);

   target = (SDL_Rect){
      obj->x, obj->y, tw, th
   };
   SDL_RENDERCOPY(renderer, obj_texture, NULL, &target);

   status = 0;
error:
   return status;
}

#define OBJ_DRAW(...) SDL_ZERO(obj_draw, __VA_ARGS__)

int
main(void)
{
   int exit_status = EXIT_FAILURE;
   bool quit = 0;
   SDL_Event e;

   struct obj obj = { 0, 0, 0, 0 };

   INIT_SDL();

   obj_texture = LOAD_TEXTURE("foo.png");

   while (!quit)
     {
        while (SDL_PollEvent(&e))
          {
             if (e.type == SDL_QUIT)
               quit = 1;
             obj_handle_event(&obj, &e);
          }

        OBJ_MOVE(&obj);

        SDL_SetRenderDrawColor(renderer, 0x00, 0xFF, 0x7F, 0xFF);
        SDL_RENDERCLEAR(renderer);
        OBJ_DRAW(&obj);
        SDL_RenderPresent(renderer);
     }

   exit_status = EXIT_SUCCESS;
error:
   SDL_DestroyTexture(obj_texture);
   close_sdl();
   exit(exit_status);
}