/*
 * Copyright (C) 2022 Rafał Dzięgiel <rafostar.github@gmail.com>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library 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
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 * License along with this library; if not, write to the
 * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
 * Boston, MA 02110-1301, USA.
 */

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

#include "gstclapperglbaseimporter.h"
#include "gst/plugin/gstgdkformats.h"
#include "gst/plugin/gstgtkutils.h"

#include <gst/gl/gstglfuncs.h>

#if GST_CLAPPER_GL_BASE_IMPORTER_HAVE_WAYLAND
#include <gdk/wayland/gdkwayland.h>
#include <gst/gl/wayland/gstgldisplay_wayland.h>
#endif

#if GST_CLAPPER_GL_BASE_IMPORTER_HAVE_X11
#include <gdk/x11/gdkx.h>
#endif
#if GST_CLAPPER_GL_BASE_IMPORTER_HAVE_X11_GLX
#include <gst/gl/x11/gstgldisplay_x11.h>
#endif
#if GST_CLAPPER_GL_BASE_IMPORTER_HAVE_X11_EGL || GST_CLAPPER_GL_BASE_IMPORTER_HAVE_WIN32_EGL
#include <gst/gl/egl/gstgldisplay_egl.h>
#endif

#if GST_CLAPPER_GL_BASE_IMPORTER_HAVE_WIN32
#include <gdk/win32/gdkwin32.h>
#endif

#if GST_CLAPPER_GL_BASE_IMPORTER_HAVE_MACOS
#include <gdk/macos/gdkmacos.h>
#endif

#define GST_CAT_DEFAULT gst_clapper_gl_base_importer_debug
GST_DEBUG_CATEGORY_STATIC (GST_CAT_DEFAULT);

#define parent_class gst_clapper_gl_base_importer_parent_class
G_DEFINE_TYPE (GstClapperGLBaseImporter, gst_clapper_gl_base_importer, GST_TYPE_CLAPPER_IMPORTER);

static GstGLContext *
wrap_current_gl (GstGLDisplay *display, GdkGLAPI gdk_gl_api, GstGLPlatform platform)
{
  GstGLAPI gst_gl_api = GST_GL_API_NONE;

  switch (gdk_gl_api) {
    case GDK_GL_API_GL:
      gst_gl_api = GST_GL_API_OPENGL | GST_GL_API_OPENGL3;
      break;
    case GDK_GL_API_GLES:
      gst_gl_api = GST_GL_API_GLES2;
      break;
    default:
      g_assert_not_reached ();
      break;
  }

  if (gst_gl_api != GST_GL_API_NONE) {
    guintptr gl_handle;

    gst_gl_display_filter_gl_api (display, gst_gl_api);

    if ((gl_handle = gst_gl_context_get_current_gl_context (platform)))
      return gst_gl_context_new_wrapped (display, gl_handle, platform, gst_gl_api);
  }

  return NULL;
}

static gboolean
retrieve_gl_context_on_main (GstClapperGLBaseImporter *self)
{
  GstClapperGLBaseImporterClass *gl_bi_class = GST_CLAPPER_GL_BASE_IMPORTER_GET_CLASS (self);
  GdkDisplay *gdk_display;
  GdkGLContext *gdk_context;
  GError *error = NULL;
  GdkGLAPI gdk_gl_api;
  GstGLPlatform platform = GST_GL_PLATFORM_NONE;
  gint gl_major = 0, gl_minor = 0;

  if (!gtk_init_check ()) {
    GST_ERROR_OBJECT (self, "Could not ensure GTK initialization");
    return FALSE;
  }

  /* Make sure we are clean here, otherwise data sharing
   * between GL-based importers may lead to leaks */
  gst_clear_object (&self->wrapped_context);
  g_clear_object (&self->gdk_context);
  gst_clear_object (&self->gst_display);

  gdk_display = gdk_display_get_default ();

  if (!(gdk_context = gdk_display_create_gl_context (gdk_display, &error))) {
    GST_ERROR_OBJECT (self, "Error creating Gdk GL context: %s",
        error ? error->message : "No error set by Gdk");
    g_clear_error (&error);

    return FALSE;
  }

  if (!gl_bi_class->gdk_context_realize (self, gdk_context)) {
    GST_ERROR_OBJECT (self, "Could not realize Gdk context: %" GST_PTR_FORMAT,
        gdk_context);
    g_object_unref (gdk_context);

    return FALSE;
  }
  gdk_gl_api = gdk_gl_context_get_api (gdk_context);

  GST_CLAPPER_GL_BASE_IMPORTER_LOCK (self);

  self->gdk_context = gdk_context;

#if GST_CLAPPER_GL_BASE_IMPORTER_HAVE_WAYLAND
  if (GDK_IS_WAYLAND_DISPLAY (gdk_display)) {
    struct wl_display *wayland_display =
        gdk_wayland_display_get_wl_display (gdk_display);
    self->gst_display = (GstGLDisplay *)
        gst_gl_display_wayland_new_with_display (wayland_display);
  }
#endif

#if GST_CLAPPER_GL_BASE_IMPORTER_HAVE_X11
  if (GDK_IS_X11_DISPLAY (gdk_display)) {
    gpointer display_ptr;
#if GST_CLAPPER_GL_BASE_IMPORTER_HAVE_X11_EGL
    display_ptr = gdk_x11_display_get_egl_display (gdk_display);
    if (display_ptr) {
      self->gst_display = (GstGLDisplay *)
          gst_gl_display_egl_new_with_egl_display (display_ptr);
    }
#endif
#if GST_CLAPPER_GL_BASE_IMPORTER_HAVE_X11_GLX
    if (!self->gst_display) {
      display_ptr = gdk_x11_display_get_xdisplay (gdk_display);
      self->gst_display = (GstGLDisplay *)
          gst_gl_display_x11_new_with_display (display_ptr);
    }
  }
#endif
#endif

#if GST_CLAPPER_GL_BASE_IMPORTER_HAVE_WIN32
  if (GDK_IS_WIN32_DISPLAY (gdk_display)) {
#if GST_CLAPPER_GL_BASE_IMPORTER_HAVE_WIN32_EGL
    gpointer display_ptr = gdk_win32_display_get_egl_display (gdk_display);
    if (display_ptr) {
      self->gst_display = (GstGLDisplay *)
          gst_gl_display_egl_new_with_egl_display (display_ptr);
    }
#endif
#if GST_CLAPPER_GL_BASE_IMPORTER_HAVE_WIN32_WGL
    if (!self->gst_display) {
      self->gst_display =
          gst_gl_display_new_with_type (GST_GL_DISPLAY_TYPE_WIN32);
    }
  }
#endif
#endif

#if GST_CLAPPER_GL_BASE_IMPORTER_HAVE_MACOS
  if (GDK_IS_MACOS_DISPLAY (gdk_display)) {
    self->gst_display =
        gst_gl_display_new_with_type (GST_GL_DISPLAY_TYPE_COCOA);
  }
#endif

  /* Fallback to generic display */
  if (G_UNLIKELY (!self->gst_display)) {
    GST_WARNING_OBJECT (self, "Unknown Gdk display!");
    self->gst_display = gst_gl_display_new ();
  }

#if GST_CLAPPER_GL_BASE_IMPORTER_HAVE_WAYLAND
  if (GST_IS_GL_DISPLAY_WAYLAND (self->gst_display)) {
    platform = GST_GL_PLATFORM_EGL;
    GST_INFO_OBJECT (self, "Using EGL on Wayland");
    goto have_display;
  }
#endif
#if GST_CLAPPER_GL_BASE_IMPORTER_HAVE_X11_EGL
  if (GST_IS_GL_DISPLAY_EGL (self->gst_display)
      && GDK_IS_X11_DISPLAY (gdk_display)) {
    platform = GST_GL_PLATFORM_EGL;
    GST_INFO_OBJECT (self, "Using EGL on x11");
    goto have_display;
  }
#endif
#if GST_CLAPPER_GL_BASE_IMPORTER_HAVE_X11_GLX
  if (GST_IS_GL_DISPLAY_X11 (self->gst_display)) {
    platform = GST_GL_PLATFORM_GLX;
    GST_INFO_OBJECT (self, "Using GLX on x11");
    goto have_display;
  }
#endif
#if GST_CLAPPER_GL_BASE_IMPORTER_HAVE_WIN32_EGL
  if (GST_IS_GL_DISPLAY_EGL (self->gst_display)
      && GDK_IS_WIN32_DISPLAY (gdk_display)) {
    platform = GST_GL_PLATFORM_EGL;
    GST_INFO_OBJECT (self, "Using EGL on Win32");
    goto have_display;
  }
#endif
#if GST_CLAPPER_GL_BASE_IMPORTER_HAVE_WIN32_WGL
  if (gst_gl_display_get_handle_type (self->gst_display) == GST_GL_DISPLAY_TYPE_WIN32) {
    platform = GST_GL_PLATFORM_WGL;
    GST_INFO_OBJECT (self, "Using WGL on Win32");
    goto have_display;
  }
#endif
#if GST_CLAPPER_GL_BASE_IMPORTER_HAVE_MACOS
  if (gst_gl_display_get_handle_type (self->gst_display) == GST_GL_DISPLAY_TYPE_COCOA) {
    platform = GST_GL_PLATFORM_CGL;
    GST_INFO_OBJECT (self, "Using CGL on macOS");
    goto have_display;
  }
#endif

  g_clear_object (&self->gdk_context);
  gst_clear_object (&self->gst_display);

  GST_CLAPPER_GL_BASE_IMPORTER_UNLOCK (self);

  GST_ERROR_OBJECT (self, "Unsupported GL platform");
  return FALSE;

have_display:
  gdk_gl_context_make_current (self->gdk_context);

  self->wrapped_context = wrap_current_gl (self->gst_display, gdk_gl_api, platform);
  if (!self->wrapped_context) {
    GST_ERROR ("Could not retrieve Gdk OpenGL context");
    gdk_gl_context_clear_current ();

    g_clear_object (&self->gdk_context);
    gst_clear_object (&self->gst_display);

    GST_CLAPPER_GL_BASE_IMPORTER_UNLOCK (self);

    return FALSE;
  }

  GST_INFO ("Retrieved Gdk OpenGL context %" GST_PTR_FORMAT, self->wrapped_context);
  gst_gl_context_activate (self->wrapped_context, TRUE);

  if (!gst_gl_context_fill_info (self->wrapped_context, &error)) {
    GST_ERROR ("Failed to fill Gdk context info: %s", error->message);
    g_clear_error (&error);

    gst_gl_context_activate (self->wrapped_context, FALSE);

    gst_clear_object (&self->wrapped_context);
    g_clear_object (&self->gdk_context);
    gst_clear_object (&self->gst_display);

    GST_CLAPPER_GL_BASE_IMPORTER_UNLOCK (self);

    return FALSE;
  }

  gst_gl_context_get_gl_version (self->wrapped_context, &gl_major, &gl_minor);
  GST_INFO ("Using OpenGL%s %i.%i", (gdk_gl_api == GDK_GL_API_GLES) ? " ES" : "",
      gl_major, gl_minor);

  /* Deactivate in both places */
  gst_gl_context_activate (self->wrapped_context, FALSE);
  gdk_gl_context_clear_current ();

  GST_CLAPPER_GL_BASE_IMPORTER_UNLOCK (self);

  return TRUE;
}

static gboolean
retrieve_gst_context (GstClapperGLBaseImporter *self)
{
  GstGLDisplay *gst_display = NULL;
  GstGLContext *gst_context = NULL;
  GError *error = NULL;

  GST_CLAPPER_GL_BASE_IMPORTER_LOCK (self);

  gst_display = gst_object_ref (self->gst_display);

  /* GstGLDisplay operations require display object lock to be held */
  GST_OBJECT_LOCK (gst_display);

  if (!self->gst_context) {
    GST_TRACE_OBJECT (self, "Creating new GstGLContext");

    if (!gst_gl_display_create_context (gst_display, self->wrapped_context,
        &self->gst_context, &error)) {
      GST_WARNING ("Could not create OpenGL context: %s",
          error ? error->message : "Unknown");
      g_clear_error (&error);

      GST_OBJECT_UNLOCK (gst_display);
      GST_CLAPPER_GL_BASE_IMPORTER_UNLOCK (self);

      return FALSE;
    }
  }

  gst_context = gst_object_ref (self->gst_context);

  GST_CLAPPER_GL_BASE_IMPORTER_UNLOCK (self);

  gst_gl_display_add_context (gst_display, gst_context);

  GST_OBJECT_UNLOCK (gst_display);

  gst_object_unref (gst_display);
  gst_object_unref (gst_context);

  return TRUE;
}

static gboolean
gst_clapper_gl_base_importer_prepare (GstClapperImporter *importer)
{
  GstClapperGLBaseImporter *self = GST_CLAPPER_GL_BASE_IMPORTER_CAST (importer);
  gboolean need_invoke;

  GST_CLAPPER_GL_BASE_IMPORTER_LOCK (self);
  need_invoke = (!self->gdk_context || !self->gst_display || !self->wrapped_context);
  GST_CLAPPER_GL_BASE_IMPORTER_UNLOCK (self);

  if (need_invoke) {
    if (!(! !gst_gtk_invoke_on_main ((GThreadFunc) (GCallback)
        retrieve_gl_context_on_main, self)))
      return FALSE;
  }

  if (!retrieve_gst_context (self))
    return FALSE;

  if (!GST_CLAPPER_IMPORTER_CLASS (parent_class)->prepare)
    return TRUE;

  return GST_CLAPPER_IMPORTER_CLASS (parent_class)->prepare (importer);
}

static void
gst_clapper_gl_base_importer_share_data (GstClapperImporter *importer, GstClapperImporter *dest_importer)
{
  GstClapperGLBaseImporter *self = GST_CLAPPER_GL_BASE_IMPORTER (importer);

  if (GST_IS_CLAPPER_GL_BASE_IMPORTER (dest_importer)) {
    GstClapperGLBaseImporter *dest = GST_CLAPPER_GL_BASE_IMPORTER (dest_importer);

    GST_CLAPPER_GL_BASE_IMPORTER_LOCK (self);
    GST_CLAPPER_GL_BASE_IMPORTER_LOCK (dest);

    /* Successfully prepared GL importer should have all three */
    if (self->gdk_context && self->gst_display && self->wrapped_context) {
      g_clear_object (&dest->gdk_context);
      dest->gdk_context = g_object_ref (self->gdk_context);

      gst_clear_object (&dest->gst_display);
      dest->gst_display = gst_object_ref (self->gst_display);

      gst_clear_object (&dest->wrapped_context);
      dest->wrapped_context = gst_object_ref (self->wrapped_context);
    }

    /* This context is not required, we can create it ourselves
     * using gst_display and wrapped_context */
    if (self->gst_context) {
      gst_clear_object (&dest->gst_context);
      dest->gst_context = gst_object_ref (self->gst_context);
    }

    GST_CLAPPER_GL_BASE_IMPORTER_UNLOCK (dest);
    GST_CLAPPER_GL_BASE_IMPORTER_UNLOCK (self);
  }

  if (GST_CLAPPER_IMPORTER_CLASS (parent_class)->share_data)
    GST_CLAPPER_IMPORTER_CLASS (parent_class)->share_data (importer, dest_importer);
}

static gboolean
gst_clapper_gl_base_importer_handle_context_query (GstClapperImporter *importer,
    GstBaseSink *bsink, GstQuery *query)
{
  GstClapperGLBaseImporter *self = GST_CLAPPER_GL_BASE_IMPORTER_CAST (importer);
  gboolean res;

  GST_CLAPPER_GL_BASE_IMPORTER_LOCK (self);
  res = gst_gl_handle_context_query (GST_ELEMENT_CAST (bsink), query,
      self->gst_display, self->gst_context, self->wrapped_context);
  GST_CLAPPER_GL_BASE_IMPORTER_UNLOCK (self);

  return res;
}

static GstBufferPool *
gst_clapper_gl_base_importer_create_pool (GstClapperImporter *importer, GstStructure **config)
{
  GstClapperGLBaseImporter *self = GST_CLAPPER_GL_BASE_IMPORTER_CAST (importer);
  GstBufferPool *pool;

  GST_DEBUG_OBJECT (self, "Creating new GL buffer pool");

  GST_CLAPPER_GL_BASE_IMPORTER_LOCK (self);
  pool = gst_gl_buffer_pool_new (self->gst_context);
  GST_CLAPPER_GL_BASE_IMPORTER_UNLOCK (self);

  *config = gst_buffer_pool_get_config (pool);

  gst_buffer_pool_config_add_option (*config, GST_BUFFER_POOL_OPTION_VIDEO_META);
  gst_buffer_pool_config_add_option (*config, GST_BUFFER_POOL_OPTION_GL_SYNC_META);

  return pool;
}

static void
gst_clapper_gl_base_importer_add_allocation_metas (GstClapperImporter *importer, GstQuery *query)
{
  GstClapperGLBaseImporter *self = GST_CLAPPER_GL_BASE_IMPORTER_CAST (importer);

  gst_query_add_allocation_meta (query, GST_VIDEO_OVERLAY_COMPOSITION_META_API_TYPE, NULL);
  gst_query_add_allocation_meta (query, GST_VIDEO_META_API_TYPE, NULL);

  GST_CLAPPER_GL_BASE_IMPORTER_LOCK (self);
  if (self->gst_context->gl_vtable->FenceSync)
    gst_query_add_allocation_meta (query, GST_GL_SYNC_META_API_TYPE, NULL);
  GST_CLAPPER_GL_BASE_IMPORTER_UNLOCK (self);
}

static gboolean
gst_clapper_gl_base_importer_gdk_context_realize (GstClapperGLBaseImporter *self, GdkGLContext *gdk_context)
{
  GdkGLAPI allowed_apis;
  GError *error = NULL;
  const gchar *gl_env;
  gboolean success;

  GST_DEBUG_OBJECT (self, "Realizing GdkGLContext with default implementation");

  /* Use single "GST_GL_API" env to also influence Gdk GL selection */
  gl_env = g_getenv ("GST_GL_API");
  allowed_apis = (!gl_env || g_str_has_prefix (gl_env, "gles"))
      ? GDK_GL_API_GLES
      : (g_str_has_prefix (gl_env, "opengl"))
      ? GDK_GL_API_GL
      : GDK_GL_API_GL | GDK_GL_API_GLES;

  gdk_gl_context_set_allowed_apis (gdk_context, allowed_apis);
  if (!(success = gdk_gl_context_realize (gdk_context, &error))) {
    GST_WARNING_OBJECT (self, "Could not realize Gdk context with %s: %s",
        (allowed_apis & GDK_GL_API_GL) ? "GL" : "GLES", error->message);
    g_clear_error (&error);
  }
  if (!success && !gl_env) {
    gdk_gl_context_set_allowed_apis (gdk_context, GDK_GL_API_GL);
    if (!(success = gdk_gl_context_realize (gdk_context, &error))) {
      GST_WARNING_OBJECT (self, "Could not realize Gdk context with GL: %s", error->message);
      g_clear_error (&error);
    }
  }

  return success;
}

static void
gst_clapper_gl_base_importer_init (GstClapperGLBaseImporter *self)
{
  g_mutex_init (&self->lock);
}

static void
gst_clapper_gl_base_importer_finalize (GObject *object)
{
  GstClapperGLBaseImporter *self = GST_CLAPPER_GL_BASE_IMPORTER_CAST (object);

  g_clear_object (&self->gdk_context);

  gst_clear_object (&self->gst_display);
  gst_clear_object (&self->wrapped_context);
  gst_clear_object (&self->gst_context);

  g_mutex_clear (&self->lock);

  GST_CALL_PARENT (G_OBJECT_CLASS, finalize, (object));
}

static void
gst_clapper_gl_base_importer_class_init (GstClapperGLBaseImporterClass *klass)
{
  GObjectClass *gobject_class = (GObjectClass *) klass;
  GstClapperImporterClass *importer_class = (GstClapperImporterClass *) klass;
  GstClapperGLBaseImporterClass *gl_bi_class = (GstClapperGLBaseImporterClass *) klass;

  GST_DEBUG_CATEGORY_INIT (GST_CAT_DEFAULT, "clapperglbaseimporter", 0,
      "Clapper GL Base Importer");

  gobject_class->finalize = gst_clapper_gl_base_importer_finalize;

  importer_class->prepare = gst_clapper_gl_base_importer_prepare;
  importer_class->share_data = gst_clapper_gl_base_importer_share_data;
  importer_class->handle_context_query = gst_clapper_gl_base_importer_handle_context_query;
  importer_class->create_pool = gst_clapper_gl_base_importer_create_pool;
  importer_class->add_allocation_metas = gst_clapper_gl_base_importer_add_allocation_metas;

  gl_bi_class->gdk_context_realize = gst_clapper_gl_base_importer_gdk_context_realize;
}

GstCaps *
gst_clapper_gl_base_importer_make_supported_gdk_gl_caps (void)
{
  GstCaps *caps, *tmp;

  tmp = gst_caps_from_string (
      GST_VIDEO_CAPS_MAKE_WITH_FEATURES (GST_CAPS_FEATURE_MEMORY_GL_MEMORY,
          "{ " GST_GDK_GL_TEXTURE_FORMATS " }") ", "
          "texture-target = (string) { " GST_GL_TEXTURE_TARGET_2D_STR " }");

  caps = gst_caps_copy (tmp);
  gst_caps_set_features_simple (caps, gst_caps_features_new (
      GST_CAPS_FEATURE_MEMORY_GL_MEMORY,
      GST_CAPS_FEATURE_META_GST_VIDEO_OVERLAY_COMPOSITION, NULL));

  gst_caps_append (caps, tmp);

  return caps;
}

GStrv
gst_clapper_gl_base_importer_make_gl_context_types (void)
{
  GStrv context_types;
  GStrvBuilder *builder = g_strv_builder_new ();

  g_strv_builder_add (builder, GST_GL_DISPLAY_CONTEXT_TYPE);
  g_strv_builder_add (builder, "gst.gl.app_context");
  g_strv_builder_add (builder, "gst.gl.local_context");

  context_types = g_strv_builder_end (builder);
  g_strv_builder_unref (builder);

  return context_types;
}

GdkTexture *
gst_clapper_gl_base_importer_make_gl_texture (GstClapperGLBaseImporter *self,
    GstBuffer *buffer, GstVideoInfo *v_info)
{
  GdkTexture *texture;
  GstGLSyncMeta *sync_meta;
  GstVideoFrame frame;

  if (G_UNLIKELY (!gst_video_frame_map (&frame, v_info, buffer, GST_MAP_READ | GST_MAP_GL))) {
    GST_ERROR_OBJECT (self, "Could not map input buffer for reading");
    return NULL;
  }

  GST_CLAPPER_GL_BASE_IMPORTER_LOCK (self);

  /* Must have context active here for both sync meta
   * and Gdk texture format auto-detection to work */
  gdk_gl_context_make_current (self->gdk_context);
  gst_gl_context_activate (self->wrapped_context, TRUE);

  sync_meta = gst_buffer_get_gl_sync_meta (buffer);

  /* Wait for all previous OpenGL commands to complete,
   * before we start using the input texture */
  if (sync_meta) {
    gst_gl_sync_meta_set_sync_point (sync_meta, self->gst_context);
    gst_gl_sync_meta_wait (sync_meta, self->wrapped_context);
  }

  texture = gdk_gl_texture_new (
      self->gdk_context,
      *(guint *) GST_VIDEO_FRAME_PLANE_DATA (&frame, 0),
      GST_VIDEO_FRAME_WIDTH (&frame),
      GST_VIDEO_FRAME_HEIGHT (&frame),
      (GDestroyNotify) gst_buffer_unref,
      gst_buffer_ref (buffer));

  gst_gl_context_activate (self->wrapped_context, FALSE);
  gdk_gl_context_clear_current ();

  GST_CLAPPER_GL_BASE_IMPORTER_UNLOCK (self);

  gst_video_frame_unmap (&frame);

  return texture;
}