/*
 * bnxsdl12.c: the part of the SDL 1.2 API that Biniax-2 uses, on top of SDL2, for the fredygames.com
 * browser build (Emscripten). See bnxsdl12.h.
 *
 * The game draws into the "screen" surface of SDL_SetVideoMode (here 32 bits); each SDL_Flip uploads
 * it to a streaming texture and presents it.
 *
 * Copyright (C) 2026 FredyGames. Distributed under the same zlib license as Biniax-2.
 */
#include "bnxsdl12.h"

static SDL_Window *window = NULL;
static SDL_Renderer *renderer = NULL;
static SDL_Texture *texture = NULL;
static SDL_Surface *screen = NULL;

SDL_Surface *
SDL_SetVideoMode (int width, int height, int bpp, Uint32 flags)
{
  (void) bpp;
  (void) flags;
  if (window == NULL)
    {
      window = SDL_CreateWindow ("BINIAX-2", SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, width,
                                 height, 0);
      if (window == NULL)
        return NULL;
      renderer = SDL_CreateRenderer (window, -1, 0);
      if (renderer == NULL)
        return NULL;
    }
  if (texture != NULL)
    SDL_DestroyTexture (texture);
  if (screen != NULL)
    SDL_FreeSurface (screen);
  texture = SDL_CreateTexture (renderer, SDL_PIXELFORMAT_RGB888, SDL_TEXTUREACCESS_STREAMING, width,
                               height);
  screen = SDL_CreateRGBSurfaceWithFormat (0, width, height, 32, SDL_PIXELFORMAT_RGB888);
  return screen;
}

int
SDL_Flip (SDL_Surface * surface)
{
  if (surface != screen || texture == NULL)
    return -1;
  SDL_UpdateTexture (texture, NULL, screen->pixels, screen->pitch);
  SDL_RenderClear (renderer);
  SDL_RenderCopy (renderer, texture, NULL, NULL);
  SDL_RenderPresent (renderer);
  return 0;
}

void
SDL_WM_SetCaption (const char *title, const char *icon)
{
  (void) icon;
  if (window != NULL && title != NULL)
    SDL_SetWindowTitle (window, title);
}

int
SDL_SetAlpha (SDL_Surface * surface, Uint32 flags, Uint8 alpha)
{
  if (surface == NULL)
    return -1;
  if (flags & SDL_SRCALPHA)
    {
      SDL_SetSurfaceBlendMode (surface, SDL_BLENDMODE_BLEND);
      SDL_SetSurfaceAlphaMod (surface, alpha);
    }
  else
    {
      SDL_SetSurfaceBlendMode (surface, SDL_BLENDMODE_NONE);
      SDL_SetSurfaceAlphaMod (surface, 255);
    }
  return 0;
}

SDL_Surface *
SDL_DisplayFormat (SDL_Surface * surface)
{
  /* like SDL 1.2: the screen's format, without per-pixel alpha */
  if (surface == NULL || screen == NULL)
    return NULL;
  return SDL_ConvertSurface (surface, screen->format, 0);
}