#include <SDL.h>
#define STB_NO_STDIO
#define STB_IMAGE_IMPLEMENTATION
#define STB_ASSERT(x)
#define STB_ONLY_PNG
#include "stb_image.h"
#include "util.h"
#include "sprites.h"
#include "assets.h"

typedef struct {
  unsigned char *im_data;
  SDL_Surface *surface;
} sprite_set_t;

static sprite_set_t
sprite_set_init(
  const asset_id_t asset_id
) {
  sprite_set_t set;
  // get asset
  const asset_t * const asset = asset_get(asset_id);

  // load image
  int im_w, im_h;
  set.im_data = stbi_load_from_memory(asset->buf, asset->len, &im_w, &im_h, NULL, 4);
  if (!set.im_data) {
    die("stbi_load(): %s", stbi_failure_reason());
  }

  // create surface
  set.surface = SDL_CreateRGBSurfaceWithFormatFrom(set.im_data, im_w, im_h, 32, 4 * im_w, SDL_PIXELFORMAT_RGBA32);
  if (!set.surface) {
    die("SDLCreateRGBSurfaceFrom(): %s", SDL_GetError());
  }

  // return sprite set
  return set;
}

static void
sprite_set_fini(
  const sprite_set_t * const set
) {
  // free main surface
  SDL_FreeSurface(set->surface);

  // free image data
  stbi_image_free(set->im_data);
}

static SDL_Surface *
sprite_set_get_sprite_surface(
  const sprite_set_t * const set,
  const sprite_t icon_sprite
) {
  // create surface
  SDL_Surface *r = SDL_CreateRGBSurfaceWithFormat(0, 32, 32, 32, SDL_PIXELFORMAT_RGBA32);
  if (!r) {
    die("SDL_CreateRGBSurfaceWithFormat(): %s", SDL_GetError());
  }

  // copy from main surface
  const SDL_Rect src_rect = { icon_sprite * 32, 0, 32, 32 };
  if (SDL_BlitScaled(set->surface, &src_rect, r, NULL)) {
    die("SDL_BlitScaled(): %s", SDL_GetError());
  }

  // return surface
  return r;
}

void
sprites_init(
  SDL_Renderer * const renderer,
  SDL_Texture **sprites
) {
  // init sprite set from asset
  sprite_set_t set = sprite_set_init(ASSET_SPRITES_PNG);

  // create sprite textures
  for (size_t i = 0; i < SPRITE_LAST; i++) {
    // create surface
    SDL_Surface *s = sprite_set_get_sprite_surface(&set, i);

    // create texture
    sprites[i] = SDL_CreateTextureFromSurface(renderer, s);
    if (!sprites[i]) {
      die("SDLCreateTextureFromSurface(): %s", SDL_GetError());
    }

    // free surface
    SDL_FreeSurface(s);
  }

  // fini sprite set
  sprite_set_fini(&set);
}

SDL_Rect
sprites_get_rect(
  const sprite_t sprite
) {
  const int x = ((sprite < SPRITE_LAST) ? sprite : SPRITE_NONE) * 32;
  return (SDL_Rect) { .x = x, .y = 0, .w = 32, .h = 32 };
}

void
sprites_set_window_icon(
  SDL_Window * const win,
  const sprite_t sprite_id
) {
  // init sprite set from asset
  sprite_set_t set = sprite_set_init(ASSET_SPRITES_PNG);

  // create icon surface
  SDL_Surface *surface = sprite_set_get_sprite_surface(&set, sprite_id);

  // set window icon
  SDL_SetWindowIcon(win, surface);

  // free icon surface
  SDL_FreeSurface(surface);

  // fini sprite set
  sprite_set_fini(&set);
}