/*
  * Copyright (c) 2019 Paul B Mahol
  *
  * This file is part of FFmpeg.
  *
  * FFmpeg is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation; either
  * version 2.1 of the License, or (at your option) any later version.
  *
  * FFmpeg 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
  * Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public
  * License along with FFmpeg; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
 #include "libavutil/common.h"
 #include "libavutil/opt.h"
 #include "libavutil/pixdesc.h"
 #include "avfilter.h"
 #include "formats.h"
 #include "internal.h"
 
 typedef struct ScrollContext {
     const AVClass *class;
 
     float h_speed, v_speed;
     float h_pos, v_pos;
     float h_ipos, v_ipos;
 

     int pos_h[4], pos_v[4];
 

     const AVPixFmtDescriptor *desc;
     int nb_planes;
     int bytes;
 
     int planewidth[4];
     int planeheight[4];
 } ScrollContext;
 
 static int query_formats(AVFilterContext *ctx)
 {
     static const enum AVPixelFormat pix_fmts[] = {
         AV_PIX_FMT_YUVA444P, AV_PIX_FMT_YUV444P, AV_PIX_FMT_YUV440P,
         AV_PIX_FMT_YUVJ444P, AV_PIX_FMT_YUVJ440P,
         AV_PIX_FMT_YUVA422P, AV_PIX_FMT_YUV422P, AV_PIX_FMT_YUVA420P, AV_PIX_FMT_YUV420P,
         AV_PIX_FMT_YUVJ422P, AV_PIX_FMT_YUVJ420P,
         AV_PIX_FMT_YUVJ411P, AV_PIX_FMT_YUV411P, AV_PIX_FMT_YUV410P,
         AV_PIX_FMT_YUV420P9, AV_PIX_FMT_YUV422P9, AV_PIX_FMT_YUV444P9,
         AV_PIX_FMT_YUV420P10, AV_PIX_FMT_YUV422P10, AV_PIX_FMT_YUV444P10,
         AV_PIX_FMT_YUV420P12, AV_PIX_FMT_YUV422P12, AV_PIX_FMT_YUV444P12, AV_PIX_FMT_YUV440P12,
         AV_PIX_FMT_YUV420P14, AV_PIX_FMT_YUV422P14, AV_PIX_FMT_YUV444P14,
         AV_PIX_FMT_YUV420P16, AV_PIX_FMT_YUV422P16, AV_PIX_FMT_YUV444P16,
         AV_PIX_FMT_YUVA420P9, AV_PIX_FMT_YUVA422P9, AV_PIX_FMT_YUVA444P9,

         AV_PIX_FMT_YUVA422P12, AV_PIX_FMT_YUVA444P12,

         AV_PIX_FMT_YUVA420P10, AV_PIX_FMT_YUVA422P10, AV_PIX_FMT_YUVA444P10,
         AV_PIX_FMT_YUVA420P16, AV_PIX_FMT_YUVA422P16, AV_PIX_FMT_YUVA444P16,
         AV_PIX_FMT_GBRP, AV_PIX_FMT_GBRP9, AV_PIX_FMT_GBRP10,
         AV_PIX_FMT_GBRP12, AV_PIX_FMT_GBRP14, AV_PIX_FMT_GBRP16,
         AV_PIX_FMT_GBRAP, AV_PIX_FMT_GBRAP10, AV_PIX_FMT_GBRAP12, AV_PIX_FMT_GBRAP16,
         AV_PIX_FMT_GRAY8, AV_PIX_FMT_GRAY9, AV_PIX_FMT_GRAY10, AV_PIX_FMT_GRAY12, AV_PIX_FMT_GRAY14, AV_PIX_FMT_GRAY16,
         AV_PIX_FMT_NONE
     };
 
     AVFilterFormats *fmts_list = ff_make_format_list(pix_fmts);
     if (!fmts_list)
         return AVERROR(ENOMEM);
     return ff_set_common_formats(ctx, fmts_list);
 }
 

 typedef struct ThreadData {
     AVFrame *in, *out;
 } ThreadData;
 
 static int scroll_slice(AVFilterContext *ctx, void *arg, int jobnr,
                         int nb_jobs)

 {

     ScrollContext *s = ctx->priv;
     ThreadData *td = arg;
     AVFrame *in = td->in;
     AVFrame *out = td->out;
 
     for (int p = 0; p < s->nb_planes; p++) {
         const uint8_t *src = in->data[p];
         const int h = s->planeheight[p];
         const int w = s->planewidth[p] * s->bytes;
         const int slice_start = (h * jobnr) / nb_jobs;
         const int slice_end = (h * (jobnr+1)) / nb_jobs;
         uint8_t *dst = out->data[p] + slice_start * out->linesize[p];
 
         for (int y = slice_start; y < slice_end; y++) {
             int yy = (y + s->pos_v[p]) % h;
             const uint8_t *ssrc = src + yy * in->linesize[p];
 
             if (s->pos_h[p] < w)
                 memcpy(dst, ssrc + s->pos_h[p], w - s->pos_h[p]);
             if (s->pos_h[p] > 0)
                 memcpy(dst + w - s->pos_h[p], ssrc, s->pos_h[p]);
 
             dst += out->linesize[p];
         }
     }
 
     return 0;
 }
 
 static void scroll(AVFilterContext *ctx, AVFrame *in, AVFrame *out)
 {
     ScrollContext *s = ctx->priv;
     ThreadData td;

     int h_pos, v_pos;
 
     s->h_pos = fmodf(s->h_pos, in->width);
     s->v_pos = fmodf(s->v_pos, in->height);
 
     h_pos = s->h_pos;
     v_pos = s->v_pos;
 
     if (h_pos < 0)
         h_pos += in->width;
     if (v_pos < 0)
         v_pos += in->height;
 

     s->pos_v[1] = s->pos_v[2] = AV_CEIL_RSHIFT(v_pos, s->desc->log2_chroma_h);
     s->pos_v[0] = s->pos_v[3] = v_pos;
     s->pos_h[1] = s->pos_h[2] = AV_CEIL_RSHIFT(h_pos, s->desc->log2_chroma_w) * s->bytes;
     s->pos_h[0] = s->pos_h[3] = h_pos * s->bytes;

     td.in = in; td.out = out;
     ctx->internal->execute(ctx, scroll_slice, &td, NULL,
                            FFMIN(out->height, ff_filter_get_nb_threads(ctx)));

 
     s->h_pos += s->h_speed * in->width;
     s->v_pos += s->v_speed * in->height;
 }
 
 static int filter_frame(AVFilterLink *inlink, AVFrame *in)
 {
     AVFilterContext *ctx = inlink->dst;
     AVFilterLink *outlink = ctx->outputs[0];
     AVFrame *out;
 
     out = ff_get_video_buffer(outlink, outlink->w, outlink->h);
     if (!out) {
         av_frame_free(&in);
         return AVERROR(ENOMEM);
     }
     av_frame_copy_props(out, in);
 

     scroll(ctx, in, out);

 
     av_frame_free(&in);
     return ff_filter_frame(outlink, out);
 }
 
 static int config_input(AVFilterLink *inlink)
 {
     AVFilterContext *ctx = inlink->dst;
     ScrollContext *s = ctx->priv;
 
     s->desc = av_pix_fmt_desc_get(inlink->format);
     s->nb_planes = s->desc->nb_components;
     s->bytes = (s->desc->comp[0].depth + 7) >> 3;
 
     s->planeheight[1] = s->planeheight[2] = AV_CEIL_RSHIFT(inlink->h, s->desc->log2_chroma_h);
     s->planeheight[0] = s->planeheight[3] = inlink->h;
     s->planewidth[1]  = s->planewidth[2]  = AV_CEIL_RSHIFT(inlink->w, s->desc->log2_chroma_w);
     s->planewidth[0]  = s->planewidth[3]  = inlink->w;
 
     s->h_pos = (1.f - s->h_ipos) * inlink->w;
     s->v_pos = (1.f - s->v_ipos) * inlink->h;
 
     return 0;
 }
 
 #define OFFSET(x) offsetof(ScrollContext, x)
 #define FLAGS AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM

 #define VFT AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_RUNTIME_PARAM

 
 static const AVOption scroll_options[] = {

     { "horizontal", "set the horizontal scrolling speed", OFFSET(h_speed), AV_OPT_TYPE_FLOAT, {.dbl=0.}, -1., 1., VFT },
     { "h",          "set the horizontal scrolling speed", OFFSET(h_speed), AV_OPT_TYPE_FLOAT, {.dbl=0.}, -1., 1., VFT },
     { "vertical",   "set the vertical scrolling speed",   OFFSET(v_speed), AV_OPT_TYPE_FLOAT, {.dbl=0.}, -1., 1., VFT },
     { "v",          "set the vertical scrolling speed",   OFFSET(v_speed), AV_OPT_TYPE_FLOAT, {.dbl=0.}, -1., 1., VFT },

     { "hpos",       "set initial horizontal position",    OFFSET(h_ipos),  AV_OPT_TYPE_FLOAT, {.dbl=0.},   0, 1., FLAGS },
     { "vpos",       "set initial vertical position",      OFFSET(v_ipos),  AV_OPT_TYPE_FLOAT, {.dbl=0.},   0, 1., FLAGS },
     { NULL }
 };
 
 AVFILTER_DEFINE_CLASS(scroll);
 
 static const AVFilterPad scroll_inputs[] = {
     {
         .name           = "default",
         .type           = AVMEDIA_TYPE_VIDEO,
         .config_props   = config_input,
         .filter_frame   = filter_frame,
     },
     { NULL }
 };
 
 static const AVFilterPad scroll_outputs[] = {
     {
         .name = "default",
         .type = AVMEDIA_TYPE_VIDEO,
     },
     { NULL }
 };
 
 AVFilter ff_vf_scroll = {
     .name          = "scroll",
     .description   = NULL_IF_CONFIG_SMALL("Scroll input video."),
     .priv_size     = sizeof(ScrollContext),
     .priv_class    = &scroll_class,
     .query_formats = query_formats,
     .inputs        = scroll_inputs,
     .outputs       = scroll_outputs,

     .flags         = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC | AVFILTER_FLAG_SLICE_THREADS,

     .process_command = ff_filter_process_command,

 };