/* 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},
  {V4L2_PIX_FMT_SUNXI_TILED_NV12, 1, GST_VIDEO_FORMAT_NV12_32L32, 8, 422},
  {V4L2_PIX_FMT_NV12_4L4, 1, GST_VIDEO_FORMAT_NV12_4L4, 8, 420},
  {V4L2_PIX_FMT_MM21, 2, GST_VIDEO_FORMAT_NV12_16L32S, 8, 420},
  {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 void
set_stride (GstVideoInfo * info, gint plane, gint stride)
{
  const GstVideoFormatInfo *finfo = info->finfo;

  if (GST_VIDEO_FORMAT_INFO_IS_TILED (finfo)) {
    gint x_tiles, y_tiles, ws, hs, padded_height;

    ws = GST_VIDEO_FORMAT_INFO_TILE_WS (finfo);
    hs = GST_VIDEO_FORMAT_INFO_TILE_HS (finfo);

    /* this only works for what we support, NV12 subsampled tiles */
    if (GST_VIDEO_FORMAT_INFO_HAS_SUBTILES (finfo) && plane == 1)
      hs -= 1;

    padded_height = GST_VIDEO_FORMAT_INFO_SCALE_HEIGHT (finfo, plane,
        info->height);
    padded_height = GST_ROUND_UP_N (padded_height, 1 << hs);

    x_tiles = stride >> ws;
    y_tiles = padded_height >> hs;
    info->stride[plane] = GST_VIDEO_TILE_MAKE_STRIDE (x_tiles, y_tiles);
  } else {
    info->stride[plane] = stride;
  }
}

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;
  struct v4l2_pix_format *pix = &fmt->fmt.pix;
  gint plane;
  gsize offset = 0;
  gboolean extrapolate = FALSE;

  if (!entry)
    return FALSE;

  /* validate the entry against the format */
  if (V4L2_TYPE_IS_MULTIPLANAR (fmt->type)) {
    if (entry->num_planes != pix_mp->num_planes) {
      GST_ERROR ("Miss-matched number of planes in internal entry "
          "(%i != %i)", entry->num_planes, pix_mp->num_planes);
      return FALSE;
    }
  } else if (entry->num_planes != 1) {
    GST_ERROR ("Miss-matched number of planes in internal entry "
        "(must be 1 for non-multiplanar, got %i)", entry->num_planes);
    return FALSE;
  }

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

  if (V4L2_TYPE_IS_MULTIPLANAR (fmt->type)) {
    out_info->size = 0;
    for (plane = 0; plane < pix_mp->num_planes; plane++)
      out_info->size += pix_mp->plane_fmt[plane].sizeimage;
  } else {
    out_info->size = pix->sizeimage;
  }

  /*
   * When single allocation formats are used for planar formats we need to
   * extrapolate the per-plane stride. Do this check once to prevent
   * complex inner loop.
   */
  if (entry->num_planes == 1 && out_info->finfo->n_planes != entry->num_planes)
    extrapolate = TRUE;

  for (plane = 0; plane < GST_VIDEO_INFO_N_PLANES (out_info); plane++) {
    gint stride;

    if (V4L2_TYPE_IS_MULTIPLANAR (fmt->type)) {
      if (extrapolate)
        stride = gst_video_format_info_extrapolate_stride (out_info->finfo,
            plane, pix_mp->plane_fmt[0].bytesperline);
      else
        stride = pix_mp->plane_fmt[plane].bytesperline;
    } else {
      if (extrapolate)
        stride = gst_video_format_info_extrapolate_stride (out_info->finfo,
            plane, pix->bytesperline);
      else
        stride = pix->bytesperline;
    }

    set_stride (out_info, plane, stride);
    out_info->offset[plane] = offset;

    if ((V4L2_TYPE_IS_MULTIPLANAR (fmt->type) && !extrapolate))
      offset += pix_mp->plane_fmt[plane].sizeimage;
    else
      offset += stride * GST_VIDEO_FORMAT_INFO_SCALE_HEIGHT (out_info->finfo,
          plane, pix_mp->height);
  }

  /* Check that the extrapolation didn't overflow the reported sizeimage */
  if (extrapolate && offset > out_info->size) {
    GST_ERROR ("Extrapolated plane offset overflow the image size.");
    return FALSE;
  }

  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;
}