/* GStreamer
 * Copyright (C) 2020 Nicolas Dufresne <nicolas.dufresne@collabora.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.
 */

#include "gstv4l2format.h"

#define GST_CAT_DEFAULT gstv4l2codecs_debug
GST_DEBUG_CATEGORY_EXTERN (gstv4l2codecs_debug);

struct FormatEntry
{
  guint32 v4l2_pix_fmt;
  gint num_planes;
  GstVideoFormat gst_fmt;
  guint bitdepth;
  gint subsampling;
};

static struct FormatEntry format_map[] = {
  {V4L2_PIX_FMT_NV12, 1, GST_VIDEO_FORMAT_NV12, 8, 420},
  {V4L2_PIX_FMT_YUYV, 1, GST_VIDEO_FORMAT_YUY2, 8, 422},
  {0,}
};

static struct FormatEntry *
lookup_v4l2_fmt (guint v4l2_pix_fmt)
{
  gint i;
  struct FormatEntry *ret = NULL;

  for (i = 0; format_map[i].v4l2_pix_fmt; i++) {
    if (format_map[i].v4l2_pix_fmt == v4l2_pix_fmt) {
      ret = format_map + i;
      break;
    }
  }

  return ret;
}

static struct FormatEntry *
lookup_gst_fmt (GstVideoFormat gst_fmt)
{
  gint i;
  struct FormatEntry *ret = NULL;

  for (i = 0; format_map[i].v4l2_pix_fmt; i++) {
    if (format_map[i].gst_fmt == gst_fmt) {
      ret = format_map + i;
      break;
    }
  }

  return ret;
}

static gint
extrapolate_stride (const GstVideoFormatInfo * finfo, gint plane, gint stride)
{
  gint estride;

  switch (finfo->format) {
    case GST_VIDEO_FORMAT_NV12:
    case GST_VIDEO_FORMAT_NV12_64Z32:
    case GST_VIDEO_FORMAT_NV21:
    case GST_VIDEO_FORMAT_NV16:
    case GST_VIDEO_FORMAT_NV61:
    case GST_VIDEO_FORMAT_NV24:
      estride = (plane == 0 ? 1 : 2) *
          GST_VIDEO_FORMAT_INFO_SCALE_WIDTH (finfo, plane, stride);
      break;
    default:
      estride = GST_VIDEO_FORMAT_INFO_SCALE_WIDTH (finfo, plane, stride);
      break;
  }

  return estride;
}

gboolean
gst_v4l2_format_to_video_info (struct v4l2_format * fmt,
    GstVideoInfo * out_info)
{
  struct FormatEntry *entry = lookup_v4l2_fmt (fmt->fmt.pix_mp.pixelformat);
  struct v4l2_pix_format_mplane *pix_mp = &fmt->fmt.pix_mp;
  gint plane;
  gsize offset = 0;

  if (!entry)
    return FALSE;

  if (entry->num_planes != 1) {
    GST_FIXME ("Multi allocation formats are not supported yet");
    return FALSE;
  }

  if (!gst_video_info_set_format (out_info, entry->gst_fmt,
          pix_mp->width, pix_mp->height))
    return FALSE;

  /* TODO: We don't support multi-allocation yet */
  g_return_val_if_fail (pix_mp->num_planes == 1, FALSE);
  out_info->size = pix_mp->plane_fmt[0].sizeimage;

  for (plane = 0; plane < GST_VIDEO_INFO_N_PLANES (out_info); plane++) {
    gint stride = extrapolate_stride (out_info->finfo, plane,
        pix_mp->plane_fmt[0].bytesperline);

    out_info->stride[plane] = stride;
    out_info->offset[plane] = offset;

    offset += stride * GST_VIDEO_FORMAT_INFO_SCALE_HEIGHT (out_info->finfo,
        plane, pix_mp->height);
  }

  return TRUE;
}

gboolean
gst_v4l2_format_to_video_format (guint32 pix_fmt, GstVideoFormat * out_format)
{
  struct FormatEntry *entry = lookup_v4l2_fmt (pix_fmt);

  if (!entry)
    return FALSE;

  *out_format = entry->gst_fmt;
  return TRUE;
}

gboolean
gst_v4l2_format_from_video_format (GstVideoFormat format, guint32 * out_pix_fmt)
{
  struct FormatEntry *entry = lookup_gst_fmt (format);

  if (!entry)
    return FALSE;

  *out_pix_fmt = entry->v4l2_pix_fmt;
  return TRUE;
}