/*
 * Cogl
 *
 * An object oriented GL/GLES Abstraction/Utility Layer
 *
 * Copyright (C) 2011 Intel Corporation.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library. If not, see <http://www.gnu.org/licenses/>.
 *
 *
 * Authors:
 *   Neil Roberts <neil@linux.intel.com>
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <SDL.h>

#include "cogl-renderer-private.h"
#include "cogl-display-private.h"
#include "cogl-framebuffer-private.h"
#include "cogl-swap-chain-private.h"
#include "cogl-onscreen-template-private.h"
#include "cogl-context-private.h"
#include "cogl-onscreen-private.h"
#include "cogl-winsys-sdl-private.h"
#include "cogl-error-private.h"

typedef struct _CoglRendererSdl
{
  int stub;
} CoglRendererSdl;

typedef struct _CoglDisplaySdl
{
  SDL_Surface *surface;
  CoglOnscreen *onscreen;
  Uint32 video_mode_flags;
  CoglBool pending_resize_notify;
} CoglDisplaySdl;

static CoglFuncPtr
_cogl_winsys_renderer_get_proc_address (CoglRenderer *renderer,
                                        const char *name,
                                        CoglBool in_core)
{
  /* XXX: It's not totally clear whether it's safe to call this for
   * core functions. From the code it looks like the implementations
   * will fall back to using some form of dlsym if the winsys
   * GetProcAddress function returns NULL. Presumably this will work
   * in most cases apart from EGL platforms that return invalid
   * pointers for core functions. It's awkward for this code to get a
   * handle to the GL module that SDL has chosen to load so just
   * calling SDL_GL_GetProcAddress is probably the best we can do
   * here. */

#ifdef COGL_HAS_SDL_GLES_SUPPORT
  if (renderer->driver != COGL_DRIVER_GL)
    return SDL_GLES_GetProcAddress (name);
#endif

  return SDL_GL_GetProcAddress (name);
}

static void
_cogl_winsys_renderer_disconnect (CoglRenderer *renderer)
{
  SDL_Quit ();

  g_slice_free (CoglRendererSdl, renderer->winsys);
}

static CoglBool
_cogl_winsys_renderer_connect (CoglRenderer *renderer,
                               CoglError **error)
{
#ifndef COGL_HAS_SDL_GLES_SUPPORT
  if (renderer->driver != COGL_DRIVER_GL)
    {
      _cogl_set_error (error, COGL_WINSYS_ERROR,
                   COGL_WINSYS_ERROR_INIT,
                   "The SDL winsys only supports the GL driver");
      return FALSE;
    }
#endif /* COGL_HAS_SDL_GLES_SUPPORT */

  if (SDL_Init (SDL_INIT_VIDEO) == -1)
    {
      _cogl_set_error (error, COGL_WINSYS_ERROR,
                   COGL_WINSYS_ERROR_INIT,
                   "SDL_Init failed: %s",
                   SDL_GetError ());
      return FALSE;
    }

  renderer->winsys = g_slice_new0 (CoglRendererSdl);

  return TRUE;
}

static void
_cogl_winsys_display_destroy (CoglDisplay *display)
{
  CoglDisplaySdl *sdl_display = display->winsys;

  _COGL_RETURN_IF_FAIL (sdl_display != NULL);

  /* No need to destroy the surface - it is freed by SDL_Quit */

  g_slice_free (CoglDisplaySdl, display->winsys);
  display->winsys = NULL;
}

static void
set_gl_attribs_from_framebuffer_config (CoglFramebufferConfig *config)
{
  SDL_GL_SetAttribute (SDL_GL_RED_SIZE, 1);
  SDL_GL_SetAttribute (SDL_GL_GREEN_SIZE, 1);
  SDL_GL_SetAttribute (SDL_GL_BLUE_SIZE, 1);
  SDL_GL_SetAttribute (SDL_GL_DEPTH_SIZE, 1);

  SDL_GL_SetAttribute (SDL_GL_STENCIL_SIZE,
                       config->need_stencil ? 1 : 0);

  if (config->swap_chain->length >= 0)
    SDL_GL_SetAttribute (SDL_GL_DOUBLEBUFFER,
                         config->swap_chain->length > 1 ? 1 : 0);

  SDL_GL_SetAttribute (SDL_GL_ALPHA_SIZE,
                       config->swap_chain->has_alpha ? 1 : 0);
}

static CoglBool
_cogl_winsys_display_setup (CoglDisplay *display,
                            CoglError **error)
{
  CoglDisplaySdl *sdl_display;

  _COGL_RETURN_VAL_IF_FAIL (display->winsys == NULL, FALSE);

  sdl_display = g_slice_new0 (CoglDisplaySdl);
  display->winsys = sdl_display;

  set_gl_attribs_from_framebuffer_config (&display->onscreen_template->config);

  switch (display->renderer->driver)
    {
    case COGL_DRIVER_GL:
      sdl_display->video_mode_flags = SDL_OPENGL;
      break;

    case COGL_DRIVER_GL3:
      _cogl_set_error (error, COGL_WINSYS_ERROR,
                       COGL_WINSYS_ERROR_INIT,
                       "The SDL winsys does not support GL 3");
      goto error;

#ifdef COGL_HAS_SDL_GLES_SUPPORT
    case COGL_DRIVER_GLES2:
      sdl_display->video_mode_flags = SDL_OPENGLES;
      SDL_GL_SetAttribute (SDL_GL_CONTEXT_MAJOR_VERSION, 2);
      SDL_GL_SetAttribute (SDL_GL_CONTEXT_MINOR_VERSION, 0);
      break;

    case COGL_DRIVER_GLES1:
      sdl_display->video_mode_flags = SDL_OPENGLES;
      SDL_GL_SetAttribute (SDL_GL_CONTEXT_MAJOR_VERSION, 1);
      SDL_GL_SetAttribute (SDL_GL_CONTEXT_MINOR_VERSION, 1);
      break;
#endif /* COGL_HAS_SDL_GLES_SUPPORT */

    default:
      g_assert_not_reached ();
    }

  /* There's no way to know what size the application will need until
     it creates the first onscreen but we need to set the video mode
     now so that we can get a GL context. We'll have to just guess at
     a size an resize it later */
  sdl_display->surface = SDL_SetVideoMode (640, 480, /* width/height */
                                           0, /* bitsperpixel */
                                           sdl_display->video_mode_flags);

  if (sdl_display->surface == NULL)
    {
      _cogl_set_error (error, COGL_WINSYS_ERROR,
                   COGL_WINSYS_ERROR_INIT,
                   "SDL_SetVideoMode failed: %s",
                   SDL_GetError ());
      goto error;
    }

  return TRUE;

error:
  _cogl_winsys_display_destroy (display);
  return FALSE;
}

static CoglFilterReturn
sdl_event_filter_cb (SDL_Event *event, void *data)
{
  if (event->type == SDL_VIDEORESIZE)
    {
      CoglContext *context = data;
      CoglDisplay *display = context->display;
      CoglDisplaySdl *sdl_display = display->winsys;
      float width = event->resize.w;
      float height = event->resize.h;
      CoglFramebuffer *framebuffer;

      if (!sdl_display->onscreen)
        return COGL_FILTER_CONTINUE;

      sdl_display->surface = SDL_SetVideoMode (width, height,
                                               0, /* bitsperpixel */
                                               sdl_display->video_mode_flags);

      framebuffer = COGL_FRAMEBUFFER (sdl_display->onscreen);
      _cogl_framebuffer_winsys_update_size (framebuffer, width, height);

      /* We only want to notify that a resize happened when the
         application calls cogl_context_dispatch so instead of immediately
         notifying we'll set a flag to remember to notify later */
      sdl_display->pending_resize_notify = TRUE;

      return COGL_FILTER_CONTINUE;
    }

  return COGL_FILTER_CONTINUE;
}

static CoglBool
_cogl_winsys_context_init (CoglContext *context, CoglError **error)
{
  CoglRenderer *renderer = context->display->renderer;

  if (G_UNLIKELY (renderer->sdl_event_type_set == FALSE))
    g_error ("cogl_sdl_renderer_set_event_type() or cogl_sdl_context_new() "
             "must be called during initialization");

  _cogl_renderer_add_native_filter (renderer,
                                    (CoglNativeFilterFunc)sdl_event_filter_cb,
                                    context);

  return _cogl_context_update_features (context, error);
}

static void
_cogl_winsys_context_deinit (CoglContext *context)
{
}

static void
_cogl_winsys_onscreen_bind (CoglOnscreen *onscreen)
{
}

static void
_cogl_winsys_onscreen_deinit (CoglOnscreen *onscreen)
{
  CoglContext *context = COGL_FRAMEBUFFER (onscreen)->context;
  CoglDisplay *display = context->display;
  CoglDisplaySdl *sdl_display = display->winsys;

  sdl_display->onscreen = NULL;
}

static CoglBool
_cogl_winsys_onscreen_init (CoglOnscreen *onscreen,
                            CoglError **error)
{
  CoglFramebuffer *framebuffer = COGL_FRAMEBUFFER (onscreen);
  CoglContext *context = framebuffer->context;
  CoglDisplay *display = context->display;
  CoglDisplaySdl *sdl_display = display->winsys;
  CoglBool flags_changed = FALSE;
  int width, height;

  if (sdl_display->onscreen)
    {
      _cogl_set_error (error, COGL_WINSYS_ERROR,
                   COGL_WINSYS_ERROR_CREATE_ONSCREEN,
                   "SDL winsys only supports a single onscreen window");
      return FALSE;
    }

  width = cogl_framebuffer_get_width (framebuffer);
  height = cogl_framebuffer_get_height (framebuffer);

  if (cogl_onscreen_get_resizable (onscreen))
    {
      sdl_display->video_mode_flags |= SDL_RESIZABLE;
      flags_changed = TRUE;
    }

  /* Try to update the video size using the onscreen size */
  if (width != sdl_display->surface->w ||
      height != sdl_display->surface->h ||
      flags_changed)
    {
      sdl_display->surface = SDL_SetVideoMode (width, height,
                                               0, /* bitsperpixel */
                                               sdl_display->video_mode_flags);

      if (sdl_display->surface == NULL)
        {
          _cogl_set_error (error, COGL_WINSYS_ERROR,
                       COGL_WINSYS_ERROR_CREATE_ONSCREEN,
                       "SDL_SetVideoMode failed: %s",
                       SDL_GetError ());
          return FALSE;
        }
    }

  _cogl_framebuffer_winsys_update_size (framebuffer,
                                        sdl_display->surface->w,
                                        sdl_display->surface->h);

  sdl_display->onscreen = onscreen;

  return TRUE;
}

static void
_cogl_winsys_onscreen_swap_buffers (CoglOnscreen *onscreen)
{
  SDL_GL_SwapBuffers ();
}

static void
_cogl_winsys_onscreen_update_swap_throttled (CoglOnscreen *onscreen)
{
  /* SDL doesn't appear to provide a way to set this */
}

static void
_cogl_winsys_onscreen_set_visibility (CoglOnscreen *onscreen,
                                      CoglBool visibility)
{
  /* SDL doesn't appear to provide a way to set this */
}

static void
_cogl_winsys_onscreen_set_resizable (CoglOnscreen *onscreen,
                                     CoglBool resizable)
{
  CoglFramebuffer *framebuffer = COGL_FRAMEBUFFER (onscreen);
  CoglContext *context = framebuffer->context;
  CoglDisplay *display = context->display;
  CoglDisplaySdl *sdl_display = display->winsys;
  int width, height;

  width = cogl_framebuffer_get_width (framebuffer);
  height = cogl_framebuffer_get_height (framebuffer);

  if (resizable)
    sdl_display->video_mode_flags |= SDL_RESIZABLE;
  else
    sdl_display->video_mode_flags &= ~SDL_RESIZABLE;

  sdl_display->surface = SDL_SetVideoMode (width, height,
                                           0, /* bitsperpixel */
                                           sdl_display->video_mode_flags);
}

static void
_cogl_winsys_poll_dispatch (CoglContext *context,
                            const CoglPollFD *poll_fds,
                            int n_poll_fds)
{
  CoglDisplay *display = context->display;
  CoglDisplaySdl *sdl_display = display->winsys;

  if (sdl_display->pending_resize_notify)
    {
      CoglOnscreen *onscreen = sdl_display->onscreen;

      g_return_if_fail (onscreen != NULL);

      _cogl_onscreen_notify_resize (onscreen);

      sdl_display->pending_resize_notify = FALSE;
    }
}

const CoglWinsysVtable *
_cogl_winsys_sdl_get_vtable (void)
{
  static CoglBool vtable_inited = FALSE;
  static CoglWinsysVtable vtable;

  /* It would be nice if we could use C99 struct initializers here
     like the GLX backend does. However this code is more likely to be
     compiled using Visual Studio which (still!) doesn't support them
     so we initialize it in code instead */

  if (!vtable_inited)
    {
      memset (&vtable, 0, sizeof (vtable));

      vtable.id = COGL_WINSYS_ID_SDL;
      vtable.name = "SDL";
      vtable.renderer_get_proc_address = _cogl_winsys_renderer_get_proc_address;
      vtable.renderer_connect = _cogl_winsys_renderer_connect;
      vtable.renderer_disconnect = _cogl_winsys_renderer_disconnect;
      vtable.display_setup = _cogl_winsys_display_setup;
      vtable.display_destroy = _cogl_winsys_display_destroy;
      vtable.context_init = _cogl_winsys_context_init;
      vtable.context_deinit = _cogl_winsys_context_deinit;
      vtable.onscreen_init = _cogl_winsys_onscreen_init;
      vtable.onscreen_deinit = _cogl_winsys_onscreen_deinit;
      vtable.onscreen_bind = _cogl_winsys_onscreen_bind;
      vtable.onscreen_swap_buffers = _cogl_winsys_onscreen_swap_buffers;
      vtable.onscreen_update_swap_throttled =
        _cogl_winsys_onscreen_update_swap_throttled;
      vtable.onscreen_set_visibility = _cogl_winsys_onscreen_set_visibility;
      vtable.onscreen_set_resizable = _cogl_winsys_onscreen_set_resizable;

      vtable.poll_dispatch = _cogl_winsys_poll_dispatch;

      vtable_inited = TRUE;
    }

  return &vtable;
}