/* GStreamer Intel MSDK plugin
 * Copyright (c) 2018, Intel Corporation
 * Copyright (c) 2018, Igalia S.L.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 *
 * 3. Neither the name of the copyright holder nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGDECE
 * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
 * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "gstmsdkcontext.h"
#ifndef _WIN32
#include <fcntl.h>
#include <unistd.h>
#include <va/va_drm.h>
#include <gudev/gudev.h>
#endif

GST_DEBUG_CATEGORY_STATIC (gst_debug_msdkcontext);
#define GST_CAT_DEFAULT gst_debug_msdkcontext

#define GST_MSDK_CONTEXT_GET_PRIVATE(obj) \
  (G_TYPE_INSTANCE_GET_PRIVATE ((obj), GST_TYPE_MSDK_CONTEXT, \
      GstMsdkContextPrivate))

#define gst_msdk_context_parent_class parent_class
G_DEFINE_TYPE_WITH_CODE (GstMsdkContext, gst_msdk_context, GST_TYPE_OBJECT,
    GST_DEBUG_CATEGORY_INIT (gst_debug_msdkcontext, "msdkcontext", 0,
        "MSDK Context"));

struct _GstMsdkContextPrivate
{
  mfxSession session;
  GList *cached_alloc_responses;
  gboolean hardware;
  gboolean is_joined;
  GstMsdkContextJobType job_type;
  gint shared_async_depth;
  GMutex mutex;
  GList *child_session_list;
#ifndef _WIN32
  gint fd;
  VADisplay dpy;
#endif
};

#ifndef _WIN32

static gint
get_device_id (void)
{
  GUdevClient *client = NULL;
  GUdevEnumerator *e = NULL;
  GList *devices, *l;
  GUdevDevice *dev, *parent;
  const gchar *devnode_path;
  const gchar *devnode_files[2] = { "renderD[0-9]*", "card[0-9]*" };
  int fd = -1, i;

  client = g_udev_client_new (NULL);
  if (!client)
    goto done;

  e = g_udev_enumerator_new (client);
  if (!e)
    goto done;

  g_udev_enumerator_add_match_subsystem (e, "drm");
  for (i = 0; i < 2; i++) {
    g_udev_enumerator_add_match_name (e, devnode_files[i]);
    devices = g_udev_enumerator_execute (e);

    for (l = devices; l != NULL; l = l->next) {
      dev = (GUdevDevice *) l->data;

      parent = g_udev_device_get_parent (dev);
      if (strcmp (g_udev_device_get_subsystem (parent), "pci") != 0) {
        g_object_unref (parent);
        continue;
      }
      g_object_unref (parent);

      devnode_path = g_udev_device_get_device_file (dev);
      fd = open (devnode_path, O_RDWR | O_CLOEXEC);
      if (fd < 0)
        continue;
      GST_DEBUG ("Opened the drm device node %s", devnode_path);
      break;
    }

    g_list_foreach (devices, (GFunc) gst_object_unref, NULL);
    g_list_free (devices);
    if (fd >= 0)
      goto done;
  }

done:
  if (e)
    g_object_unref (e);
  if (client)
    g_object_unref (client);

  return fd;
}


static gboolean
gst_msdk_context_use_vaapi (GstMsdkContext * context)
{
  gint fd;
  gint maj_ver, min_ver;
  VADisplay va_dpy = NULL;
  VAStatus va_status;
  mfxStatus status;
  GstMsdkContextPrivate *priv = context->priv;

  fd = get_device_id ();
  if (fd < 0) {
    GST_ERROR ("Couldn't find a drm device node to open");
    return FALSE;
  }

  va_dpy = vaGetDisplayDRM (fd);
  if (!va_dpy) {
    GST_ERROR ("Couldn't get a VA DRM display");
    goto failed;
  }

  va_status = vaInitialize (va_dpy, &maj_ver, &min_ver);
  if (va_status != VA_STATUS_SUCCESS) {
    GST_ERROR ("Couldn't initialize VA DRM display");
    goto failed;
  }

  status = MFXVideoCORE_SetHandle (priv->session, MFX_HANDLE_VA_DISPLAY,
      (mfxHDL) va_dpy);
  if (status != MFX_ERR_NONE) {
    GST_ERROR ("Setting VAAPI handle failed (%s)",
        msdk_status_to_string (status));
    goto failed;
  }

  priv->fd = fd;
  priv->dpy = va_dpy;

  return TRUE;

failed:
  if (va_dpy)
    vaTerminate (va_dpy);
  close (fd);
  return FALSE;
}
#endif

static gboolean
gst_msdk_context_open (GstMsdkContext * context, gboolean hardware,
    GstMsdkContextJobType job_type)
{
  GstMsdkContextPrivate *priv = context->priv;

  priv->job_type = job_type;
  priv->hardware = hardware;
  priv->session = msdk_open_session (hardware);
  if (!priv->session)
    goto failed;

#ifndef _WIN32
  priv->fd = -1;

  if (hardware) {
    if (!gst_msdk_context_use_vaapi (context))
      goto failed;
  }
#endif

  return TRUE;

failed:
  msdk_close_session (priv->session);
  gst_object_unref (context);
  return FALSE;
}

static void
gst_msdk_context_init (GstMsdkContext * context)
{
  GstMsdkContextPrivate *priv = GST_MSDK_CONTEXT_GET_PRIVATE (context);

  context->priv = priv;

  g_mutex_init (&priv->mutex);
}

static void
release_child_session (gpointer session)
{
  mfxStatus status;

  mfxSession _session = session;
  status = MFXDisjoinSession (_session);
  if (status != MFX_ERR_NONE)
    GST_WARNING ("failed to disjoin (%s)", msdk_status_to_string (status));
  msdk_close_session (_session);
}

static void
gst_msdk_context_finalize (GObject * obj)
{
  GstMsdkContext *context = GST_MSDK_CONTEXT_CAST (obj);
  GstMsdkContextPrivate *priv = context->priv;

  /* child sessions will be closed when the parent session is closed */
  if (priv->is_joined)
    goto done;
  else
    g_list_free_full (priv->child_session_list, release_child_session);

  msdk_close_session (priv->session);
  g_mutex_clear (&priv->mutex);

#ifndef _WIN32
  if (priv->dpy)
    vaTerminate (priv->dpy);
  if (priv->fd >= 0)
    close (priv->fd);
#endif

done:
  G_OBJECT_CLASS (parent_class)->finalize (obj);
}

static void
gst_msdk_context_class_init (GstMsdkContextClass * klass)
{
  GObjectClass *const g_object_class = G_OBJECT_CLASS (klass);
  g_type_class_add_private (klass, sizeof (GstMsdkContextPrivate));

  g_object_class->finalize = gst_msdk_context_finalize;
}

GstMsdkContext *
gst_msdk_context_new (gboolean hardware, GstMsdkContextJobType job_type)
{
  GstMsdkContext *obj = g_object_new (GST_TYPE_MSDK_CONTEXT, NULL);

  if (obj && !gst_msdk_context_open (obj, hardware, job_type)) {
    if (obj)
      gst_object_unref (obj);
    return NULL;
  }

  return obj;
}

GstMsdkContext *
gst_msdk_context_new_with_parent (GstMsdkContext * parent)
{
  mfxStatus status;
  GstMsdkContext *obj = g_object_new (GST_TYPE_MSDK_CONTEXT, NULL);
  GstMsdkContextPrivate *priv = obj->priv;
  GstMsdkContextPrivate *parent_priv = parent->priv;

  status = MFXCloneSession (parent_priv->session, &priv->session);
  if (status != MFX_ERR_NONE) {
    GST_ERROR ("Failed to clone mfx session");
    return NULL;
  }

  status = MFXJoinSession (parent_priv->session, priv->session);
  if (status != MFX_ERR_NONE) {
    GST_ERROR ("Failed to join mfx session");
    return NULL;
  }

  priv->is_joined = TRUE;
  priv->hardware = parent_priv->hardware;
  priv->job_type = parent_priv->job_type;
  parent_priv->child_session_list =
      g_list_prepend (parent_priv->child_session_list, priv->session);
#ifndef _WIN32
  priv->dpy = parent_priv->dpy;
  priv->fd = parent_priv->fd;

  if (priv->hardware) {
    status = MFXVideoCORE_SetHandle (priv->session, MFX_HANDLE_VA_DISPLAY,
        (mfxHDL) parent_priv->dpy);
  }
#endif

  return obj;
}

mfxSession
gst_msdk_context_get_session (GstMsdkContext * context)
{
  return context->priv->session;
}

gpointer
gst_msdk_context_get_handle (GstMsdkContext * context)
{
#ifndef _WIN32
  return context->priv->dpy;
#else
  return NULL;
#endif
}

gint
gst_msdk_context_get_fd (GstMsdkContext * context)
{
#ifndef _WIN32
  return context->priv->fd;
#else
  return -1;
#endif
}

static gint
_find_response (gconstpointer resp, gconstpointer comp_resp)
{
  GstMsdkAllocResponse *cached_resp = (GstMsdkAllocResponse *) resp;
  mfxFrameAllocResponse *_resp = (mfxFrameAllocResponse *) comp_resp;

  return cached_resp ? cached_resp->mem_ids != _resp->mids : -1;
}

static gint
_find_request (gconstpointer resp, gconstpointer req)
{
  GstMsdkAllocResponse *cached_resp = (GstMsdkAllocResponse *) resp;
  mfxFrameAllocRequest *_req = (mfxFrameAllocRequest *) req;

  return cached_resp ? cached_resp->request.Type != _req->Type : -1;
}

GstMsdkAllocResponse *
gst_msdk_context_get_cached_alloc_responses (GstMsdkContext * context,
    mfxFrameAllocResponse * resp)
{
  GstMsdkContextPrivate *priv = context->priv;
  GList *l =
      g_list_find_custom (priv->cached_alloc_responses, resp, _find_response);

  if (l)
    return l->data;
  else
    return NULL;
}

GstMsdkAllocResponse *
gst_msdk_context_get_cached_alloc_responses_by_request (GstMsdkContext *
    context, mfxFrameAllocRequest * req)
{
  GstMsdkContextPrivate *priv = context->priv;
  GList *l =
      g_list_find_custom (priv->cached_alloc_responses, req, _find_request);

  if (l)
    return l->data;
  else
    return NULL;
}

static void
create_surfaces (GstMsdkContext * context, GstMsdkAllocResponse * resp)
{
  gint i;
  mfxMemId *mem_id;
  mfxFrameSurface1 *surface;

  for (i = 0; i < resp->response->NumFrameActual; i++) {
    mem_id = resp->mem_ids[i];
    surface = (mfxFrameSurface1 *) g_slice_new0 (mfxFrameSurface1);
    if (!surface) {
      GST_ERROR ("failed to allocate surface");
      break;
    }
    surface->Data.MemId = mem_id;
    resp->surfaces_avail = g_list_prepend (resp->surfaces_avail, surface);
  }
}

static void
free_surface (gpointer surface)
{
  g_slice_free1 (sizeof (mfxFrameSurface1), surface);
}

static void
remove_surfaces (GstMsdkContext * context, GstMsdkAllocResponse * resp)
{
  g_list_free_full (resp->surfaces_used, free_surface);
  g_list_free_full (resp->surfaces_avail, free_surface);
  g_list_free_full (resp->surfaces_locked, free_surface);
}

void
gst_msdk_context_add_alloc_response (GstMsdkContext * context,
    GstMsdkAllocResponse * resp)
{
  context->priv->cached_alloc_responses =
      g_list_prepend (context->priv->cached_alloc_responses, resp);

  create_surfaces (context, resp);
}

gboolean
gst_msdk_context_remove_alloc_response (GstMsdkContext * context,
    mfxFrameAllocResponse * resp)
{
  GstMsdkAllocResponse *msdk_resp;
  GstMsdkContextPrivate *priv = context->priv;
  GList *l =
      g_list_find_custom (priv->cached_alloc_responses, resp, _find_response);

  if (!l)
    return FALSE;

  msdk_resp = l->data;

  remove_surfaces (context, msdk_resp);

  g_slice_free1 (sizeof (GstMsdkAllocResponse), msdk_resp);
  priv->cached_alloc_responses =
      g_list_delete_link (priv->cached_alloc_responses, l);

  return TRUE;
}

static gboolean
check_surfaces_available (GstMsdkContext * context, GstMsdkAllocResponse * resp)
{
  GList *l;
  mfxFrameSurface1 *surface = NULL;
  GstMsdkContextPrivate *priv = context->priv;
  gboolean ret = FALSE;

  g_mutex_lock (&priv->mutex);
  for (l = resp->surfaces_locked; l; l = l->next) {
    surface = l->data;
    if (!surface->Data.Locked) {
      resp->surfaces_locked = g_list_remove (resp->surfaces_locked, surface);
      resp->surfaces_avail = g_list_prepend (resp->surfaces_avail, surface);
      ret = TRUE;
    }
  }
  g_mutex_unlock (&priv->mutex);

  return ret;
}

/*
 * There are 3 lists here in GstMsdkContext as the following:
 * 1. surfaces_avail : surfaces which are free and unused anywhere
 * 2. surfaces_used : surfaces coupled with a gst buffer and being used now.
 * 3. surfaces_locked : surfaces still locked even after the gst buffer is released.
 *
 * Note that they need to be protected by mutex to be thread-safe.
 */

mfxFrameSurface1 *
gst_msdk_context_get_surface_available (GstMsdkContext * context,
    mfxFrameAllocResponse * resp)
{
  GList *l;
  mfxFrameSurface1 *surface = NULL;
  GstMsdkAllocResponse *msdk_resp =
      gst_msdk_context_get_cached_alloc_responses (context, resp);
  gint retry = 0;
  GstMsdkContextPrivate *priv = context->priv;

retry:
  g_mutex_lock (&priv->mutex);
  for (l = msdk_resp->surfaces_avail; l; l = l->next) {
    surface = l->data;

    if (!surface->Data.Locked) {
      msdk_resp->surfaces_avail =
          g_list_remove (msdk_resp->surfaces_avail, surface);
      msdk_resp->surfaces_used =
          g_list_prepend (msdk_resp->surfaces_used, surface);
      break;
    }
  }
  g_mutex_unlock (&priv->mutex);

  /*
   * If a msdk context is shared by multiple msdk elements,
   * upstream msdk element sometimes needs to wait for a gst buffer
   * to be released in downstream.
   *
   * Poll the pool for a maximum of 20 milisecnds.
   *
   * FIXME: Is there any better way to handle this case?
   */
  if (!surface && retry < 20) {
    /* If there's no surface available, find unlocked surfaces in the locked list,
     * take it back to the available list and then search again.
     */
    check_surfaces_available (context, msdk_resp);
    retry++;
    g_usleep (1000);
    goto retry;
  }

  return surface;
}

void
gst_msdk_context_put_surface_locked (GstMsdkContext * context,
    mfxFrameAllocResponse * resp, mfxFrameSurface1 * surface)
{
  GstMsdkContextPrivate *priv = context->priv;
  GstMsdkAllocResponse *msdk_resp =
      gst_msdk_context_get_cached_alloc_responses (context, resp);

  g_mutex_lock (&priv->mutex);
  if (!g_list_find (msdk_resp->surfaces_locked, surface)) {
    msdk_resp->surfaces_used =
        g_list_remove (msdk_resp->surfaces_used, surface);
    msdk_resp->surfaces_locked =
        g_list_prepend (msdk_resp->surfaces_locked, surface);
  }
  g_mutex_unlock (&priv->mutex);
}

void
gst_msdk_context_put_surface_available (GstMsdkContext * context,
    mfxFrameAllocResponse * resp, mfxFrameSurface1 * surface)
{
  GstMsdkContextPrivate *priv = context->priv;
  GstMsdkAllocResponse *msdk_resp =
      gst_msdk_context_get_cached_alloc_responses (context, resp);

  g_mutex_lock (&priv->mutex);
  if (!g_list_find (msdk_resp->surfaces_avail, surface)) {
    msdk_resp->surfaces_used =
        g_list_remove (msdk_resp->surfaces_used, surface);
    msdk_resp->surfaces_avail =
        g_list_prepend (msdk_resp->surfaces_avail, surface);
  }
  g_mutex_unlock (&priv->mutex);
}

GstMsdkContextJobType
gst_msdk_context_get_job_type (GstMsdkContext * context)
{
  return context->priv->job_type;
}

void
gst_msdk_context_add_job_type (GstMsdkContext * context,
    GstMsdkContextJobType job_type)
{
  context->priv->job_type |= job_type;
}

gint
gst_msdk_context_get_shared_async_depth (GstMsdkContext * context)
{
  return context->priv->shared_async_depth;
}

void
gst_msdk_context_add_shared_async_depth (GstMsdkContext * context,
    gint async_depth)
{
  context->priv->shared_async_depth += async_depth;
}