/* GStreamer
 * Copyright (C) <1999> Erik Walthinsen <omega@cse.ogi.edu>
 * Copyright (C) 2005-2012 David Schleef <ds@schleef.org>
 * Copyright (C) <2019> Seungha Yang <seungha.yang@navercorp.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.
 */

/**
 * SECTION:element-cudaconvert
 * @title: cudaconvert
 *
 * Convert video frames between supported video formats.
 *
 * ## Example launch line
 * |[
 * gst-launch-1.0 -v videotestsrc ! video/x-raw,format=Y444_16LE ! cudaupload ! cudaconvert ! cudadownload ! autovideosink
 * ]|
 *  This will output a test video (generated in Y444_16LE format) in a video
 * window. If the video sink selected does not support Y444_16LE
 * cudaconvert will automatically convert the video to a format understood
 * by the video sink.
 *
 */

#ifdef HAVE_CONFIG_H
#  include <config.h>
#endif

#include "gstcudaconvert.h"
#include "gstcudautils.h"

GST_DEBUG_CATEGORY_STATIC (gst_cuda_convert_debug);
#define GST_CAT_DEFAULT gst_cuda_convert_debug

#define gst_cuda_convert_parent_class parent_class
G_DEFINE_TYPE (GstCudaConvert, gst_cuda_convert, GST_TYPE_CUDA_BASE_FILTER);

static GstCaps *gst_cuda_convert_transform_caps (GstBaseTransform * trans,
    GstPadDirection direction, GstCaps * caps, GstCaps * filter);
static GstCaps *gst_cuda_convert_fixate_caps (GstBaseTransform * base,
    GstPadDirection direction, GstCaps * caps, GstCaps * othercaps);
static gboolean gst_cuda_convert_filter_meta (GstBaseTransform * trans,
    GstQuery * query, GType api, const GstStructure * params);
static gboolean
gst_cuda_convert_set_info (GstCudaBaseTransform * btrans, GstCaps * incaps,
    GstVideoInfo * in_info, GstCaps * outcaps, GstVideoInfo * out_info);

/* copies the given caps */
static GstCaps *
gst_cuda_convert_caps_remove_format_info (GstCaps * caps)
{
  GstStructure *st;
  GstCapsFeatures *f;
  gint i, n;
  GstCaps *res;
  GstCapsFeatures *feature =
      gst_caps_features_from_string (GST_CAPS_FEATURE_MEMORY_CUDA_MEMORY);

  res = gst_caps_new_empty ();

  n = gst_caps_get_size (caps);
  for (i = 0; i < n; i++) {
    st = gst_caps_get_structure (caps, i);
    f = gst_caps_get_features (caps, i);

    /* If this is already expressed by the existing caps
     * skip this structure */
    if (i > 0 && gst_caps_is_subset_structure_full (res, st, f))
      continue;

    st = gst_structure_copy (st);
    /* Only remove format info for the cases when we can actually convert */
    if (!gst_caps_features_is_any (f)
        && gst_caps_features_is_equal (f, feature))
      gst_structure_remove_fields (st, "format", "colorimetry", "chroma-site",
          NULL);

    gst_caps_append_structure_full (res, st, gst_caps_features_copy (f));
  }
  gst_caps_features_free (feature);

  return res;
}

/*
 * This is an incomplete matrix of in formats and a score for the prefered output
 * format.
 *
 *         out: RGB24   RGB16  ARGB  AYUV  YUV444  YUV422 YUV420 YUV411 YUV410  PAL  GRAY
 *  in
 * RGB24          0      2       1     2     2       3      4      5      6      7    8
 * RGB16          1      0       1     2     2       3      4      5      6      7    8
 * ARGB           2      3       0     1     4       5      6      7      8      9    10
 * AYUV           3      4       1     0     2       5      6      7      8      9    10
 * YUV444         2      4       3     1     0       5      6      7      8      9    10
 * YUV422         3      5       4     2     1       0      6      7      8      9    10
 * YUV420         4      6       5     3     2       1      0      7      8      9    10
 * YUV411         4      6       5     3     2       1      7      0      8      9    10
 * YUV410         6      8       7     5     4       3      2      1      0      9    10
 * PAL            1      3       2     6     4       6      7      8      9      0    10
 * GRAY           1      4       3     2     1       5      6      7      8      9    0
 *
 * PAL or GRAY are never prefered, if we can we would convert to PAL instead
 * of GRAY, though
 * less subsampling is prefered and if any, preferably horizontal
 * We would like to keep the alpha, even if we would need to to colorspace conversion
 * or lose depth.
 */
#define SCORE_FORMAT_CHANGE       1
#define SCORE_DEPTH_CHANGE        1
#define SCORE_ALPHA_CHANGE        1
#define SCORE_CHROMA_W_CHANGE     1
#define SCORE_CHROMA_H_CHANGE     1
#define SCORE_PALETTE_CHANGE      1

#define SCORE_COLORSPACE_LOSS     2     /* RGB <-> YUV */
#define SCORE_DEPTH_LOSS          4     /* change bit depth */
#define SCORE_ALPHA_LOSS          8     /* lose the alpha channel */
#define SCORE_CHROMA_W_LOSS      16     /* vertical subsample */
#define SCORE_CHROMA_H_LOSS      32     /* horizontal subsample */
#define SCORE_PALETTE_LOSS       64     /* convert to palette format */
#define SCORE_COLOR_LOSS        128     /* convert to GRAY */

#define COLORSPACE_MASK (GST_VIDEO_FORMAT_FLAG_YUV | \
                         GST_VIDEO_FORMAT_FLAG_RGB | GST_VIDEO_FORMAT_FLAG_GRAY)
#define ALPHA_MASK      (GST_VIDEO_FORMAT_FLAG_ALPHA)
#define PALETTE_MASK    (GST_VIDEO_FORMAT_FLAG_PALETTE)

/* calculate how much loss a conversion would be */
static void
score_value (GstBaseTransform * base, const GstVideoFormatInfo * in_info,
    const GValue * val, gint * min_loss, const GstVideoFormatInfo ** out_info)
{
  const gchar *fname;
  const GstVideoFormatInfo *t_info;
  GstVideoFormatFlags in_flags, t_flags;
  gint loss;

  fname = g_value_get_string (val);
  t_info = gst_video_format_get_info (gst_video_format_from_string (fname));
  if (!t_info)
    return;

  /* accept input format immediately without loss */
  if (in_info == t_info) {
    *min_loss = 0;
    *out_info = t_info;
    return;
  }

  loss = SCORE_FORMAT_CHANGE;

  in_flags = GST_VIDEO_FORMAT_INFO_FLAGS (in_info);
  in_flags &= ~GST_VIDEO_FORMAT_FLAG_LE;
  in_flags &= ~GST_VIDEO_FORMAT_FLAG_COMPLEX;
  in_flags &= ~GST_VIDEO_FORMAT_FLAG_UNPACK;

  t_flags = GST_VIDEO_FORMAT_INFO_FLAGS (t_info);
  t_flags &= ~GST_VIDEO_FORMAT_FLAG_LE;
  t_flags &= ~GST_VIDEO_FORMAT_FLAG_COMPLEX;
  t_flags &= ~GST_VIDEO_FORMAT_FLAG_UNPACK;

  if ((t_flags & PALETTE_MASK) != (in_flags & PALETTE_MASK)) {
    loss += SCORE_PALETTE_CHANGE;
    if (t_flags & PALETTE_MASK)
      loss += SCORE_PALETTE_LOSS;
  }

  if ((t_flags & COLORSPACE_MASK) != (in_flags & COLORSPACE_MASK)) {
    loss += SCORE_COLORSPACE_LOSS;
    if (t_flags & GST_VIDEO_FORMAT_FLAG_GRAY)
      loss += SCORE_COLOR_LOSS;
  }

  if ((t_flags & ALPHA_MASK) != (in_flags & ALPHA_MASK)) {
    loss += SCORE_ALPHA_CHANGE;
    if (in_flags & ALPHA_MASK)
      loss += SCORE_ALPHA_LOSS;
  }

  if ((in_info->h_sub[1]) != (t_info->h_sub[1])) {
    loss += SCORE_CHROMA_H_CHANGE;
    if ((in_info->h_sub[1]) < (t_info->h_sub[1]))
      loss += SCORE_CHROMA_H_LOSS;
  }
  if ((in_info->w_sub[1]) != (t_info->w_sub[1])) {
    loss += SCORE_CHROMA_W_CHANGE;
    if ((in_info->w_sub[1]) < (t_info->w_sub[1]))
      loss += SCORE_CHROMA_W_LOSS;
  }

  if ((in_info->bits) != (t_info->bits)) {
    loss += SCORE_DEPTH_CHANGE;
    if ((in_info->bits) > (t_info->bits))
      loss += SCORE_DEPTH_LOSS;
  }

  GST_DEBUG_OBJECT (base, "score %s -> %s = %d",
      GST_VIDEO_FORMAT_INFO_NAME (in_info),
      GST_VIDEO_FORMAT_INFO_NAME (t_info), loss);

  if (loss < *min_loss) {
    GST_DEBUG_OBJECT (base, "found new best %d", loss);
    *out_info = t_info;
    *min_loss = loss;
  }
}

static void
gst_cuda_convert_class_init (GstCudaConvertClass * klass)
{
  GstElementClass *element_class = GST_ELEMENT_CLASS (klass);
  GstBaseTransformClass *trans_class = GST_BASE_TRANSFORM_CLASS (klass);
  GstCudaBaseTransformClass *btrans_class =
      GST_CUDA_BASE_TRANSFORM_CLASS (klass);

  gst_element_class_set_static_metadata (element_class,
      "CUDA Colorspace converter",
      "Filter/Converter/Video/Hardware",
      "Converts video from one colorspace to another using CUDA",
      "Seungha Yang <seungha.yang@navercorp.com>");

  trans_class->passthrough_on_same_caps = TRUE;

  trans_class->transform_caps =
      GST_DEBUG_FUNCPTR (gst_cuda_convert_transform_caps);
  trans_class->fixate_caps = GST_DEBUG_FUNCPTR (gst_cuda_convert_fixate_caps);
  trans_class->filter_meta = GST_DEBUG_FUNCPTR (gst_cuda_convert_filter_meta);

  btrans_class->set_info = GST_DEBUG_FUNCPTR (gst_cuda_convert_set_info);

  GST_DEBUG_CATEGORY_INIT (gst_cuda_convert_debug,
      "cudaconvert", 0, "Video ColorSpace convert using CUDA");
}

static void
gst_cuda_convert_init (GstCudaConvert * convert)
{
}

static GstCaps *
gst_cuda_convert_transform_caps (GstBaseTransform * trans,
    GstPadDirection direction, GstCaps * caps, GstCaps * filter)
{
  GstCaps *tmp, *tmp2;
  GstCaps *result;

  /* Get all possible caps that we can transform to */
  tmp = gst_cuda_convert_caps_remove_format_info (caps);

  if (filter) {
    tmp2 = gst_caps_intersect_full (filter, tmp, GST_CAPS_INTERSECT_FIRST);
    gst_caps_unref (tmp);
    tmp = tmp2;
  }

  result = tmp;

  GST_DEBUG_OBJECT (trans, "transformed %" GST_PTR_FORMAT " into %"
      GST_PTR_FORMAT, caps, result);

  return result;
}

/* fork of gstvideoconvert */
static void
gst_cuda_convert_fixate_format (GstBaseTransform * base, GstCaps * caps,
    GstCaps * result)
{
  GstStructure *ins, *outs;
  const gchar *in_format;
  const GstVideoFormatInfo *in_info, *out_info = NULL;
  gint min_loss = G_MAXINT;
  guint i, capslen;

  ins = gst_caps_get_structure (caps, 0);
  in_format = gst_structure_get_string (ins, "format");
  if (!in_format)
    return;

  GST_DEBUG_OBJECT (base, "source format %s", in_format);

  in_info =
      gst_video_format_get_info (gst_video_format_from_string (in_format));
  if (!in_info)
    return;

  outs = gst_caps_get_structure (result, 0);

  capslen = gst_caps_get_size (result);
  GST_DEBUG_OBJECT (base, "iterate %d structures", capslen);
  for (i = 0; i < capslen; i++) {
    GstStructure *tests;
    const GValue *format;

    tests = gst_caps_get_structure (result, i);
    format = gst_structure_get_value (tests, "format");
    /* should not happen */
    if (format == NULL)
      continue;

    if (GST_VALUE_HOLDS_LIST (format)) {
      gint j, len;

      len = gst_value_list_get_size (format);
      GST_DEBUG_OBJECT (base, "have %d formats", len);
      for (j = 0; j < len; j++) {
        const GValue *val;

        val = gst_value_list_get_value (format, j);
        if (G_VALUE_HOLDS_STRING (val)) {
          score_value (base, in_info, val, &min_loss, &out_info);
          if (min_loss == 0)
            break;
        }
      }
    } else if (G_VALUE_HOLDS_STRING (format)) {
      score_value (base, in_info, format, &min_loss, &out_info);
    }
  }
  if (out_info)
    gst_structure_set (outs, "format", G_TYPE_STRING,
        GST_VIDEO_FORMAT_INFO_NAME (out_info), NULL);
}

static GstCaps *
gst_cuda_convert_fixate_caps (GstBaseTransform * trans,
    GstPadDirection direction, GstCaps * caps, GstCaps * othercaps)
{
  GstCaps *result;

  GST_DEBUG_OBJECT (trans, "trying to fixate othercaps %" GST_PTR_FORMAT
      " based on caps %" GST_PTR_FORMAT, othercaps, caps);

  result = gst_caps_intersect (othercaps, caps);
  if (gst_caps_is_empty (result)) {
    gst_caps_unref (result);
    result = othercaps;
  } else {
    gst_caps_unref (othercaps);
  }

  GST_DEBUG_OBJECT (trans, "now fixating %" GST_PTR_FORMAT, result);

  result = gst_caps_make_writable (result);
  gst_cuda_convert_fixate_format (trans, caps, result);

  /* fixate remaining fields */
  result = gst_caps_fixate (result);

  if (direction == GST_PAD_SINK) {
    if (gst_caps_is_subset (caps, result)) {
      gst_caps_replace (&result, caps);
    }
  }

  return result;
}

static gboolean
gst_cuda_convert_filter_meta (GstBaseTransform * trans, GstQuery * query,
    GType api, const GstStructure * params)
{
  /* This element cannot passthrough the crop meta, because it would convert the
   * wrong sub-region of the image, and worst, our output image may not be large
   * enough for the crop to be applied later */
  if (api == GST_VIDEO_CROP_META_API_TYPE)
    return FALSE;

  /* propose all other metadata upstream */
  return TRUE;
}

static gboolean
gst_cuda_convert_set_info (GstCudaBaseTransform * btrans, GstCaps * incaps,
    GstVideoInfo * in_info, GstCaps * outcaps, GstVideoInfo * out_info)
{
  /* these must match */
  if (in_info->width != out_info->width || in_info->height != out_info->height
      || in_info->fps_n != out_info->fps_n || in_info->fps_d != out_info->fps_d)
    goto format_mismatch;

  /* if present, these must match too */
  if (in_info->par_n != out_info->par_n || in_info->par_d != out_info->par_d)
    goto format_mismatch;

  /* if present, these must match too */
  if (in_info->interlace_mode != out_info->interlace_mode)
    goto format_mismatch;

  return GST_CUDA_BASE_TRANSFORM_CLASS (parent_class)->set_info (btrans, incaps,
      in_info, outcaps, out_info);

  /* ERRORS */
format_mismatch:
  {
    GST_ERROR_OBJECT (btrans, "input and output formats do not match");
    return FALSE;
  }
}
