/*
 * zazsdl12.c: the part of the SDL 1.2 API that Zaz uses, on top of SDL2, for the fredygames.com browser
 * build (Emscripten). See zazsdl12.h. The game draws with OpenGL; SDL_SetVideoMode opens a window with a
 * GL context (WebGL, through Emscripten's legacy GL emulation), and SDL_GL_SwapBuffers presents the frame.
 *
 * Copyright (C) 2026 FredyGames. GNU GPL version 3 or later, like Zaz.
 */
#include "zazsdl12.h"

static SDL_Window *window = NULL;
static SDL_GLContext context = NULL;
static SDL_Surface *screen = NULL;

const SDL_VideoInfo *
SDL_GetVideoInfo (void)
{
  static SDL_VideoInfo info;
  static SDL_PixelFormat *format = NULL;
  if (format == NULL)
    format = SDL_AllocFormat (SDL_PIXELFORMAT_RGB888);
  info.vfmt = format;
  return &info;
}

SDL_Rect **
SDL_ListModes (SDL_PixelFormat * format, Uint32 flags)
{
  /* the browser build always runs at the size the page scales (see zaz-fredygames.patch) */
  static SDL_Rect mode = { 0, 0, 1024, 768 };
  static SDL_Rect *modes[] = { &mode, NULL };
  (void) format;
  (void) flags;
  return modes;
}

SDL_Surface *
SDL_SetVideoMode (int width, int height, int bpp, Uint32 flags)
{
  (void) bpp;
  (void) flags;
  if (window == NULL)
    {
      window = SDL_CreateWindow ("Zaz", SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, width, height,
                                 SDL_WINDOW_OPENGL);
      if (window == NULL)
        return NULL;
      context = SDL_GL_CreateContext (window);
      if (context == NULL)
        return NULL;
    }
  else
    SDL_SetWindowSize (window, width, height);
  if (screen != NULL)
    SDL_FreeSurface (screen);
  /* the game only reads w and h of the screen surface */
  screen = SDL_CreateRGBSurfaceWithFormat (0, width, height, 32, SDL_PIXELFORMAT_RGB888);
  return screen;
}

void
SDL_GL_SwapBuffers (void)
{
  if (window != NULL)
    SDL_GL_SwapWindow (window);
}

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

SDL_GrabMode
SDL_WM_GrabInput (SDL_GrabMode mode)
{
  /* Zaz aims at the absolute mouse position; in a page there is nothing to grab */
  return mode == SDL_GRAB_QUERY ? SDL_GRAB_OFF : mode;
}

void
SDL_WarpMouse (Uint16 x, Uint16 y)
{
  if (window != NULL)
    SDL_WarpMouseInWindow (window, x, y);
}

int
SDL_EnableUNICODE (int enable)
{
  (void) enable;
  return 1;
}

Uint16
zaz_keysym_unicode (const SDL_Keysym * keysym)
{
  SDL_Keycode sym = keysym->sym;
  int shift = (keysym->mod & KMOD_SHIFT) != 0;
  if (sym >= SDLK_a && sym <= SDLK_z)
    return (Uint16) (shift ? sym - 'a' + 'A' : sym);
  if (sym == SDLK_BACKSPACE)
    return 8;
  if (sym == SDLK_RETURN || sym == SDLK_KP_ENTER)
    return 13;
  if (sym >= 32 && sym < 127)
    return (Uint16) sym;
  return 0;
}