/* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */

/*
 * Copyright (C) 2016 Red Hat Inc.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License, or (at your option) any later version.
 *
 * This program 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
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
 * 02111-1307, USA.
 *
 * Written by:
 *     Jonas Ådahl <jadahl@gmail.com>
 */

#include "config.h"

#include "backends/meta-egl.h"
#include "meta/util.h"

#include <EGL/egl.h>
#include <EGL/eglext.h>
#include <gio/gio.h>
#include <glib.h>
#include <glib-object.h>

struct _MetaEgl
{
  GObject parent;

  PFNEGLGETPLATFORMDISPLAYEXTPROC eglGetPlatformDisplayEXT;
};

G_DEFINE_TYPE (MetaEgl, meta_egl, G_TYPE_OBJECT)

static const char *
get_egl_error_str (void)
{
  EGLint error_number;

  error_number = eglGetError ();

  switch (error_number)
    {
    case EGL_SUCCESS:
      return "The last function succeeded without error.";
      break;
    case EGL_NOT_INITIALIZED:
      return "EGL is not initialized, or could not be initialized, for the specified EGL display connection.";
      break;
    case EGL_BAD_ACCESS:
      return "EGL cannot access a requested resource (for example a context is bound in another thread).";
      break;
    case EGL_BAD_ALLOC:
      return "EGL failed to allocate resources for the requested operation.";
      break;
    case EGL_BAD_ATTRIBUTE:
      return "An unrecognized attribute or attribute value was passed in the attribute list.";
      break;
    case EGL_BAD_CONTEXT:
      return "An EGLContext argument does not name a valid EGL rendering context.";
      break;
    case EGL_BAD_CONFIG:
      return "An EGLConfig argument does not name a valid EGL frame buffer configuration.";
      break;
    case EGL_BAD_CURRENT_SURFACE:
      return "The current surface of the calling thread is a window, pixel buffer or pixmap that is no longer valid.";
      break;
    case EGL_BAD_DISPLAY:
      return "An EGLDisplay argument does not name a valid EGL display connection.";
      break;
    case EGL_BAD_SURFACE:
      return "An EGLSurface argument does not name a valid surface (window, pixel buffer or pixmap) configured for GL rendering.";
      break;
    case EGL_BAD_MATCH:
      return "Arguments are inconsistent (for example, a valid context requires buffers not supplied by a valid surface).";
      break;
    case EGL_BAD_PARAMETER:
      return "One or more argument values are invalid.";
      break;
    case EGL_BAD_NATIVE_PIXMAP:
      return "A NativePixmapType argument does not refer to a valid native pixmap.";
      break;
    case EGL_BAD_NATIVE_WINDOW:
      return "A NativeWindowType argument does not refer to a valid native window.";
      break;
    case EGL_CONTEXT_LOST:
      return "A power management event has occurred. The application must destroy all contexts and reinitialise OpenGL ES state and objects to continue rendering. ";
      break;
    default:
      return "Unknown error";
      break;
    }
}

static void
set_egl_error (GError **error)
{
  const char *error_str;

  error_str = get_egl_error_str ();
  g_set_error (error, G_IO_ERROR,
               G_IO_ERROR_FAILED,
               error_str);
}

static gboolean
extensions_string_has_extensions_valist (const char *extensions_str,
                                         char     ***missing_extensions,
                                         char       *first_extension,
                                         va_list     var_args)
{
  char **extensions;
  char *extension;
  size_t num_missing_extensions = 0;

  if (missing_extensions)
    *missing_extensions = NULL;

  extensions = g_strsplit (extensions_str, " ", -1);

  extension = first_extension;
  while (extension)
    {
      if (!g_strv_contains ((const char * const *) extensions, extension))
        {
          num_missing_extensions++;
          if (missing_extensions)
            {
              *missing_extensions = g_realloc_n (*missing_extensions,
                                                 num_missing_extensions + 1,
                                                 sizeof (const char *));
              (*missing_extensions)[num_missing_extensions - 1] = extension;
              (*missing_extensions)[num_missing_extensions] = NULL;
            }
          else
            {
              break;
            }
        }
      extension = va_arg (var_args, char *);
    }

  g_strfreev (extensions);

  return num_missing_extensions == 0;
}

gboolean
meta_egl_has_extensions (MetaEgl   *egl,
                         EGLDisplay display,
                         char    ***missing_extensions,
                         char      *first_extension,
                         ...)
{
  va_list var_args;
  const char *extensions_str;
  gboolean has_extensions;

  extensions_str = (const char *) eglQueryString (display, EGL_EXTENSIONS);
  if (!extensions_str)
    {
      g_warning ("Failed to query string: %s", get_egl_error_str ());
      return FALSE;
    }

  va_start (var_args, first_extension);
  has_extensions = extensions_string_has_extensions_valist (extensions_str,
                                                            missing_extensions,
                                                            first_extension,
                                                            var_args);
  va_end (var_args);

  return has_extensions;
}

EGLDisplay
meta_egl_get_display (MetaEgl             *egl,
                      EGLNativeDisplayType display_id,
                      GError             **error)
{
  EGLDisplay display;

  display = eglGetDisplay (display_id);
  if (display == EGL_NO_DISPLAY)
    {
      set_egl_error (error);
      return EGL_NO_DISPLAY;
    }

  return display;
}

gboolean
meta_egl_choose_config (MetaEgl      *egl,
                        EGLDisplay    display,
                        const EGLint *attrib_list,
                        EGLConfig    *chosen_config,
                        GError      **error)
{
  EGLint num_configs;
  EGLConfig *configs;
  EGLint num_matches;

  if (!eglGetConfigs (display, NULL, 0, &num_configs))
    {
      set_egl_error (error);
      return FALSE;
    }

  if (num_configs < 1)
    {
      g_set_error (error, G_IO_ERROR,
                   G_IO_ERROR_FAILED,
                   "No EGL configurations available");
      return FALSE;
    }

  configs = g_new0 (EGLConfig, num_configs);

  if (!eglChooseConfig (display, attrib_list, configs, num_configs, &num_matches))
    {
      g_free (configs);
      set_egl_error (error);
      return FALSE;
    }

  /*
   * We don't have any preference specified yet, so lets choose the first one.
   */
  *chosen_config = configs[0];

  g_free (configs);

  return TRUE;
}

EGLSurface
meta_egl_create_pbuffer_surface (MetaEgl      *egl,
                                 EGLDisplay    display,
                                 EGLConfig     config,
                                 const EGLint *attrib_list,
                                 GError      **error)
{
  EGLSurface surface;

  surface = eglCreatePbufferSurface (display, config, attrib_list);
  if (surface == EGL_NO_SURFACE)
    {
      set_egl_error (error);
      return EGL_NO_SURFACE;
    }

  return surface;
}

static gboolean
is_egl_proc_valid_real (void       *proc,
                        const char *proc_name,
                        GError    **error)
{
  if (!proc)
    {
      g_set_error (error, G_IO_ERROR,
                   G_IO_ERROR_FAILED,
                   "EGL proc '%s' not resolved",
                   proc_name);
      return FALSE;
    }

  return TRUE;
}

#define is_egl_proc_valid(proc, error) \
  is_egl_proc_valid_real (proc, #proc, error)

EGLDisplay
meta_egl_get_platform_display (MetaEgl      *egl,
                               EGLenum       platform,
                               void         *native_display,
                               const EGLint *attrib_list,
                               GError      **error)
{
  EGLDisplay display;

  if (!is_egl_proc_valid (egl->eglGetPlatformDisplayEXT, error))
    return EGL_NO_DISPLAY;

  display = egl->eglGetPlatformDisplayEXT (platform,
                                           native_display,
                                           attrib_list);
  if (display == EGL_NO_DISPLAY)
    {
      set_egl_error (error);
      return EGL_NO_DISPLAY;
    }

  return display;
}

#define GET_EGL_PROC_ADDR(proc) \
  egl->proc = (void *) eglGetProcAddress (#proc);

#define GET_EGL_PROC_ADDR_REQUIRED(proc) \
  GET_EGL_PROC_ADDR(proc) \
  if (!egl->proc) \
    { \
      meta_fatal ("Failed to get proc address for '%s'\n", #proc); \
    }

static void
meta_egl_constructed (GObject *object)
{
  MetaEgl *egl = META_EGL (object);

  GET_EGL_PROC_ADDR_REQUIRED (eglGetPlatformDisplayEXT);
}

#undef GET_EGL_PROC_ADDR

static void
meta_egl_init (MetaEgl *egl)
{
}

static void
meta_egl_class_init (MetaEglClass *klass)
{
  GObjectClass *object_class = G_OBJECT_CLASS (klass);

  object_class->constructed = meta_egl_constructed;
}