/*
 * This file is part of MPlayer.
 *
 * MPlayer is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * MPlayer 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with MPlayer; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <limits.h>

#include "config.h"
#include "common/msg.h"
#include "options/m_option.h"

#include "video/img_format.h"
#include "video/mp_image.h"
#include "vf.h"

#include "video/memcpy_pic.h"

#include "vf_lavfi.h"

enum mode { PROGRESSIVE, TOP_FIRST, BOTTOM_FIRST,
            TOP_FIRST_ANALYZE, BOTTOM_FIRST_ANALYZE,
            ANALYZE, FULL_ANALYZE, AUTO, AUTO_ANALYZE };

#define fixed_mode(p) ((p)<=BOTTOM_FIRST)

struct vf_priv_s
   {
   int mode;
   int verbose;
   unsigned char *buf[3];
   struct vf_lw_opts *lw_opts;
   };

/*
 * Copy fields from either current or buffered previous frame to the
 * output and store the current frame unmodified to the buffer.
 */

static void do_plane(unsigned char *to, unsigned char *from,
                     int w, int h, int ts, int fs,
                     unsigned char **bufp, enum mode mode)
   {
   unsigned char *buf, *end;
   int top;

   if(!*bufp)
      {
      mode=PROGRESSIVE;
      if(!(*bufp=malloc(h*w))) return;
      }

   for(end=to+h*ts, buf=*bufp, top=1; to<end; from+=fs, to+=ts, buf+=w, top^=1)
      {
      memcpy(to, mode==(top?BOTTOM_FIRST:TOP_FIRST)?buf:from, w);
      memcpy(buf, from, w);
      }
   }

/*
 * This macro interpolates the value of both fields at a point halfway
 * between lines and takes the squared difference. In field resolution
 * the point is a quarter pixel below a line in one field and a quarter
 * pixel above a line in other.
 *
 * (the result is actually multiplied by 25)
 */

#define diff(a, as, b, bs) (t=((*a-b[bs])<<2)+a[as<<1]-b[-bs], t*t)

/*
 * Find which field combination has the smallest average squared difference
 * between the fields.
 */

static enum mode analyze_plane(struct vf_instance *vf,
                               unsigned char *old, unsigned char *new,
                               int w, int h, int os, int ns, enum mode mode,
                               int unused, int fields)
   {
   double bdiff, pdiff, tdiff, scale;
   int bdif, tdif, pdif;
   int top, t;
   unsigned char *end, *rend;

   if(mode==AUTO)
      mode=fields&MP_IMGFIELD_ORDERED?fields&MP_IMGFIELD_TOP_FIRST?
         TOP_FIRST:BOTTOM_FIRST:PROGRESSIVE;
   else if(mode==AUTO_ANALYZE)
      mode=fields&MP_IMGFIELD_ORDERED?fields&MP_IMGFIELD_TOP_FIRST?
         TOP_FIRST_ANALYZE:BOTTOM_FIRST_ANALYZE:FULL_ANALYZE;

   if(fixed_mode(mode))
      bdiff=pdiff=tdiff=65536.0;
   else
      {
      bdiff=pdiff=tdiff=0.0;

      for(end=new+(h-2)*ns, new+=ns, old+=os, top=0;
          new<end; new+=ns-w, old+=os-w, top^=1)
         {
         pdif=tdif=bdif=0;

         switch(mode)
            {
            case TOP_FIRST_ANALYZE:
               if(top)
                  for(rend=new+w; new<rend; new++, old++)
                     pdif+=diff(new, ns, new, ns),
                     tdif+=diff(new, ns, old, os);
               else
                  for(rend=new+w; new<rend; new++, old++)
                     pdif+=diff(new, ns, new, ns),
                     tdif+=diff(old, os, new, ns);
               break;

            case BOTTOM_FIRST_ANALYZE:
               if(top)
                  for(rend=new+w; new<rend; new++, old++)
                     pdif+=diff(new, ns, new, ns),
                     bdif+=diff(old, os, new, ns);
               else
                  for(rend=new+w; new<rend; new++, old++)
                     pdif+=diff(new, ns, new, ns),
                     bdif+=diff(new, ns, old, os);
               break;

            case ANALYZE:
               if(top)
                  for(rend=new+w; new<rend; new++, old++)
                     tdif+=diff(new, ns, old, os),
                     bdif+=diff(old, os, new, ns);
               else
                  for(rend=new+w; new<rend; new++, old++)
                     bdif+=diff(new, ns, old, os),
                     tdif+=diff(old, os, new, ns);
               break;

            default: /* FULL_ANALYZE */
               if(top)
                  for(rend=new+w; new<rend; new++, old++)
                     pdif+=diff(new, ns, new, ns),
                     tdif+=diff(new, ns, old, os),
                     bdif+=diff(old, os, new, ns);
               else
                  for(rend=new+w; new<rend; new++, old++)
                     pdif+=diff(new, ns, new, ns),
                     bdif+=diff(new, ns, old, os),
                     tdif+=diff(old, os, new, ns);
            }

         pdiff+=(double)pdif;
         tdiff+=(double)tdif;
         bdiff+=(double)bdif;
         }

      scale=1.0/(w*(h-3))/25.0;
      pdiff*=scale;
      tdiff*=scale;
      bdiff*=scale;

      if(mode==TOP_FIRST_ANALYZE)
         bdiff=65536.0;
      else if(mode==BOTTOM_FIRST_ANALYZE)
         tdiff=65536.0;
      else if(mode==ANALYZE)
         pdiff=65536.0;

      if(bdiff<pdiff && bdiff<tdiff)
         mode=BOTTOM_FIRST;
      else if(tdiff<pdiff && tdiff<bdiff)
         mode=TOP_FIRST;
      else
         mode=PROGRESSIVE;
      }

      MP_INFO(vf, "%c", mode==BOTTOM_FIRST?'b':mode==TOP_FIRST?'t':'p');
      if(tdiff==65536.0) MP_INFO(vf, "     N/A "); else MP_INFO(vf, " %8.2f", tdiff);
      if(bdiff==65536.0) MP_INFO(vf, "     N/A "); else MP_INFO(vf, " %8.2f", bdiff);
      if(pdiff==65536.0) MP_INFO(vf, "     N/A "); else MP_INFO(vf, " %8.2f", pdiff);
      MP_INFO(vf, "        \n");

   return mode;
   }

static struct mp_image *filter(struct vf_instance *vf, struct mp_image *mpi)
   {
   enum mode mode;

   struct mp_image *dmpi = vf_alloc_out_image(vf);
   if (!dmpi)
       return NULL;
   mp_image_copy_attributes(dmpi, mpi);

   int pw[MP_MAX_PLANES] = {0};
   for (int p = 0; p < mpi->num_planes; p++)
       pw[p] = ((mpi->w * mpi->fmt.bpp[p] + 7) / 8) >> mpi->fmt.xs[p];

   mode=vf->priv->mode;

   if(!vf->priv->buf[0])
      mode=PROGRESSIVE;
   else
      mode=analyze_plane(vf, vf->priv->buf[0], mpi->planes[0],
                         pw[0], dmpi->h, pw[0], mpi->stride[0], mode,
                         vf->priv->verbose, mpi->fields);

   for (int p = 0; p < mpi->num_planes; p++) {
      do_plane(dmpi->planes[p], mpi->planes[p], pw[p], dmpi->plane_h[p],
               dmpi->stride[p], mpi->stride[p],
               &vf->priv->buf[p], mode);
   }

   talloc_free(mpi);
   return dmpi;
   }

static void uninit(struct vf_instance *vf)
   {
   if (!vf->priv)
       return;
   free(vf->priv->buf[0]);
   free(vf->priv->buf[1]);
   free(vf->priv->buf[2]);
   }

static int query_format(struct vf_instance *vf, unsigned int fmt)
{
    if (IMGFMT_IS_HWACCEL(fmt))
        return 0;
    struct mp_imgfmt_desc desc = mp_imgfmt_get_desc(fmt);
    if (desc.num_planes > 3)
        return 0;
    return vf_next_query_format(vf, fmt);
}

static const char *get_lavfi_mode(int mode)
{
    switch (mode) {
    case PROGRESSIVE: return "p";
    case TOP_FIRST: return "t";
    case BOTTOM_FIRST: return "b";
    case TOP_FIRST_ANALYZE: return "T";
    case BOTTOM_FIRST_ANALYZE: return "B";
    case ANALYZE: return "u";
    case FULL_ANALYZE: return "U";
    case AUTO: return "a";
    case AUTO_ANALYZE: return "A";
    default: return "?";
    }
}

static int vf_open(vf_instance_t *vf)
   {
   vf->filter = filter;
   vf->uninit = uninit;
   vf->query_format = query_format;

    if (vf_lw_set_graph(vf, vf->priv->lw_opts, "phase", "%s",
                        get_lavfi_mode(vf->priv->mode)) >= 0)
    {
        return 1;
    }

   return 1;
   }

#define OPT_BASE_STRUCT struct vf_priv_s
const vf_info_t vf_info_phase =
{
   .description = "phase shift fields",
   .name = "phase",
   .open = vf_open,
   .priv_size = sizeof(struct vf_priv_s),
   .priv_defaults = &(const struct vf_priv_s){
       .mode = AUTO_ANALYZE,
   },
   .options = (const struct m_option[]){
        OPT_CHOICE("mode", mode, 0,
                   ({"t", TOP_FIRST},
                    {"a", AUTO},
                    {"b", BOTTOM_FIRST},
                    {"u", ANALYZE},
                    {"T", TOP_FIRST_ANALYZE},
                    {"A", AUTO_ANALYZE},
                    {"B", BOTTOM_FIRST_ANALYZE},
                    {"U", FULL_ANALYZE},
                    {"p", PROGRESSIVE})),
        OPT_FLAG("v", verbose, 0),
        OPT_SUBSTRUCT("", lw_opts, vf_lw_conf, 0),
        {0}
   },
};
