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

struct texture
{
   SDL_Texture *sdl_texture;
   int          w;
   int          h;
};

char *title = "SDL 10 - Colour Keying";
SDL_Window *window;
SDL_Renderer *renderer;
struct texture foo_texture;
struct texture back_texture;

int
init_sdl(void)
{
   int status = -1;
   int x = SDL_WINDOWPOS_UNDEFINED;
   int y = SDL_WINDOWPOS_UNDEFINED;
   int width = 800;
   int height = 600;
   int flags = 0;       // SDL_WINDOW_FULLSCREEN_DESKTOP

   SDL_INIT(SDL_INIT_VIDEO);
   IMG_INIT(IMG_INIT_PNG);
   window = SDL_CREATEWINDOW(title, x, y, width, height, flags);
   renderer = SDL_CREATERENDERER(window, -1, SDL_RENDERER_ACCELERATED | SDL_RENDERER_PRESENTVSYNC);
   SDL_SetRenderDrawColor(renderer, 0xFF, 0x7F, 0x3F, 0xFF);
   status = 0;
error:
   return status;
}

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

int
texture_load(struct texture *t, char *path)
{
   SDL_Surface *surface = NULL;
   int status = -1;
   assert(t->sdl_texture == NULL);
   surface = IMG_LOAD(path);
   SDL_SETCOLORKEY(surface, SDL_TRUE, SDL_MapRGB(surface->format, 0x00, 0xFF, 0xFF));
   t->sdl_texture = SDL_CREATETEXTUREFROMSURFACE(renderer, surface);
   t->w = surface->w;
   t->h = surface->h;
   status = 0;
error:
   SDL_FreeSurface(surface);
   return status;
}

#define TEXTURE_LOAD(...) SDL_ZERO(texture_load, __VA_ARGS__)

void
texture_free(struct texture *t)
{
   if (t->sdl_texture == NULL)
     return;
   SDL_DestroyTexture(t->sdl_texture);
   t->sdl_texture = NULL;
   t->w = 0;
   t->h = 0;
}

int
texture_draw(struct texture *t, int x, int y)
{
   int status = -1;
   SDL_RENDERCOPY(renderer, t->sdl_texture, NULL, &(SDL_Rect){x, y, t->w, t->h});
   status = 0;
error:
   return status;
}

#define TEXTURE_DRAW(...) SDL_ZERO(texture_draw, __VA_ARGS__)

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

int ox = 240;
int oy = 240;
int x;
int y;
int d = 4;

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

   SDL_SetRenderDrawColor(renderer, 0xFF, 0xFF, 0xFF, 0xFF);
   SDL_RENDERCLEAR(renderer);
   TEXTURE_DRAW(&back_texture, 0, 0);
   TEXTURE_DRAW(&foo_texture, x, y);
   SDL_RenderPresent(renderer);
   status = 0;
error:
   return status;
}

#define DRAW(...) SDL_ZERO(draw, __VA_ARGS__)

void
key_down(SDL_Keycode k)
{
   switch (k)
     {
      case SDLK_LEFT:
        x -= d;
        break;

      case SDLK_RIGHT:
        x += d;
        break;

      case SDLK_UP:
        y -= d;
        break;

      case SDLK_DOWN:
        y += d;
        break;

      default:
        x = ox;
        y = oy;
        break;
     }
}

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

   INIT_SDL();

   TEXTURE_LOAD(&back_texture, "back.png");
   TEXTURE_LOAD(&foo_texture, "foo.png");

   x = ox;
   y = oy;

   while (!quit)
     {
        DRAW();
        SDL_WAITEVENT(&e);
        if (e.type == SDL_QUIT)
          quit = 1;
        else if (e.type == SDL_KEYDOWN)
          key_down(e.key.keysym.sym);
     }

   exit_status = EXIT_SUCCESS;
error:
   texture_free(&back_texture);
   texture_free(&foo_texture);
   close_sdl();
   exit(exit_status);
}