/*
  * Copyright (C) 2007 Richard Spindler (author of frei0r plugin from which this was derived)
  * Copyright (C) 2014 Daniel Oberhoff
  *
  * 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
  */
 
 /**
  * @file
  * Lenscorrection filter, algorithm from the frei0r plugin with the same name
 */
 #include <stdlib.h>
 #include <math.h>
 
 #include "libavutil/opt.h"
 #include "libavutil/intreadwrite.h"
 #include "libavutil/pixdesc.h"
 
 #include "avfilter.h"
 #include "internal.h"
 #include "video.h"
 
 typedef struct LenscorrectionCtx {
     const AVClass *av_class;
     unsigned int width;
     unsigned int height;
     int hsub, vsub;
     int nb_planes;
     double cx, cy, k1, k2;

     int32_t *correction[4];

 } LenscorrectionCtx;
 
 #define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
 static const AVOption lenscorrection_options[] = {
     { "cx",     "set relative center x", offsetof(LenscorrectionCtx, cx), AV_OPT_TYPE_DOUBLE, {.dbl=0.5}, 0, 1, .flags=FLAGS },
     { "cy",     "set relative center y", offsetof(LenscorrectionCtx, cy), AV_OPT_TYPE_DOUBLE, {.dbl=0.5}, 0, 1, .flags=FLAGS },
     { "k1",     "set quadratic distortion factor", offsetof(LenscorrectionCtx, k1), AV_OPT_TYPE_DOUBLE, {.dbl=0.0}, -1, 1, .flags=FLAGS },
     { "k2",     "set double quadratic distortion factor", offsetof(LenscorrectionCtx, k2), AV_OPT_TYPE_DOUBLE, {.dbl=0.0}, -1, 1, .flags=FLAGS },
     { NULL }
 };
 
 AVFILTER_DEFINE_CLASS(lenscorrection);
 
 typedef struct ThreadData {
     AVFrame *in, *out;

     int w, h;

     int plane;

     int xcenter, ycenter;

     int32_t *correction;

 } ThreadData;
 
 static int filter_slice(AVFilterContext *ctx, void *arg, int job, int nb_jobs)
 {
     ThreadData *td = (ThreadData*)arg;
     AVFrame *in = td->in;
     AVFrame *out = td->out;
 

     const int w = td->w, h = td->h;
     const int xcenter = td->xcenter;
     const int ycenter = td->ycenter;

     const int start = (h *  job   ) / nb_jobs;
     const int end   = (h * (job+1)) / nb_jobs;
     const int plane = td->plane;
     const int inlinesize = in->linesize[plane];
     const int outlinesize = out->linesize[plane];
     const uint8_t *indata = in->data[plane];
     uint8_t *outrow = out->data[plane] + start * outlinesize;
     int i;
     for (i = start; i < end; i++, outrow += outlinesize) {

         const int off_y = i - ycenter;

         uint8_t *out = outrow;
         int j;
         for (j = 0; j < w; j++) {

             const int off_x = j - xcenter;

             const int64_t radius_mult = td->correction[j + i*w];
             const int x = xcenter + ((radius_mult * off_x + (1<<23))>>24);
             const int y = ycenter + ((radius_mult * off_y + (1<<23))>>24);

             const char isvalid = x > 0 && x < w - 1 && y > 0 && y < h - 1;
             *out++ =  isvalid ? indata[y * inlinesize + x] : 0;
         }
     }
     return 0;
 }
 
 static int query_formats(AVFilterContext *ctx)
 {

     static const enum AVPixelFormat pix_fmts[] = {

         AV_PIX_FMT_YUV410P,
         AV_PIX_FMT_YUV444P,  AV_PIX_FMT_YUVJ444P,
         AV_PIX_FMT_YUV420P,  AV_PIX_FMT_YUVJ420P,
         AV_PIX_FMT_YUVA444P, AV_PIX_FMT_YUVA420P,
         AV_PIX_FMT_YUV422P,

         AV_PIX_FMT_GBRP, AV_PIX_FMT_GBRAP,

         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);

 }
 

 static av_cold void uninit(AVFilterContext *ctx)
 {
     LenscorrectionCtx *rect = ctx->priv;
     int i;
 
     for (i = 0; i < FF_ARRAY_ELEMS(rect->correction); i++) {
         av_freep(&rect->correction[i]);
     }
 }
 

 static int config_props(AVFilterLink *outlink)
 {
     AVFilterContext *ctx = outlink->src;
     LenscorrectionCtx *rect = ctx->priv;
     AVFilterLink *inlink = ctx->inputs[0];
     const AVPixFmtDescriptor *pixdesc = av_pix_fmt_desc_get(inlink->format);
     rect->hsub = pixdesc->log2_chroma_w;
     rect->vsub = pixdesc->log2_chroma_h;
     outlink->w = rect->width = inlink->w;
     outlink->h = rect->height = inlink->h;
     rect->nb_planes = av_pix_fmt_count_planes(inlink->format);
     return 0;
 }
 
 static int filter_frame(AVFilterLink *inlink, AVFrame *in)
 {
     AVFilterContext *ctx = inlink->dst;
     AVFilterLink *outlink = ctx->outputs[0];
     LenscorrectionCtx *rect = (LenscorrectionCtx*)ctx->priv;
     AVFrame *out = ff_get_video_buffer(outlink, outlink->w, outlink->h);
     int plane;
 
     if (!out) {
         av_frame_free(&in);
         return AVERROR(ENOMEM);
     }
 
     av_frame_copy_props(out, in);
 
     for (plane = 0; plane < rect->nb_planes; ++plane) {
         int hsub = plane == 1 || plane == 2 ? rect->hsub : 0;
         int vsub = plane == 1 || plane == 2 ? rect->vsub : 0;

         int hdiv = 1 << hsub;
         int vdiv = 1 << vsub;
         int w = rect->width / hdiv;
         int h = rect->height / vdiv;

         int xcenter = rect->cx * w;
         int ycenter = rect->cy * h;

         int k1 = rect->k1 * (1<<24);
         int k2 = rect->k2 * (1<<24);

         ThreadData td = {
             .in = in,
             .out  = out,
             .w  = w,
             .h  = h,

             .xcenter = xcenter,
             .ycenter = ycenter,

             .plane = plane};

 
         if (!rect->correction[plane]) {
             int i,j;

             const int64_t r2inv = (4LL<<60) / (w * w + h * h);

 
             rect->correction[plane] = av_malloc_array(w, h * sizeof(**rect->correction));
             if (!rect->correction[plane])
                 return AVERROR(ENOMEM);
             for (j = 0; j < h; j++) {
                 const int off_y = j - ycenter;
                 const int off_y2 = off_y * off_y;
                 for (i = 0; i < w; i++) {
                     const int off_x = i - xcenter;

                     const int64_t r2 = ((off_x * off_x + off_y2) * r2inv + (1LL<<31)) >> 32;
                     const int64_t r4 = (r2 * r2 + (1<<27)) >> 28;
                     const int radius_mult = (r2 * k1 + r4 * k2 + (1LL<<27) + (1LL<<52))>>28;
                     rect->correction[plane][j * w + i] = radius_mult;

                 }
             }
         }
 
         td.correction = rect->correction[plane];

         ctx->internal->execute(ctx, filter_slice, &td, NULL, FFMIN(h, ff_filter_get_nb_threads(ctx)));

     }
 
     av_frame_free(&in);
     return ff_filter_frame(outlink, out);
 }
 
 static const AVFilterPad lenscorrection_inputs[] = {
     {
         .name         = "default",
         .type         = AVMEDIA_TYPE_VIDEO,
         .filter_frame = filter_frame,
     },
     { NULL }
 };
 
 static const AVFilterPad lenscorrection_outputs[] = {
     {
         .name         = "default",
         .type         = AVMEDIA_TYPE_VIDEO,
         .config_props = config_props,
     },
     { NULL }
 };
 
 AVFilter ff_vf_lenscorrection = {
     .name          = "lenscorrection",
     .description   = NULL_IF_CONFIG_SMALL("Rectify the image by correcting for lens distortion."),
     .priv_size     = sizeof(LenscorrectionCtx),
     .query_formats = query_formats,
     .inputs        = lenscorrection_inputs,
     .outputs       = lenscorrection_outputs,
     .priv_class    = &lenscorrection_class,

     .uninit        = uninit,

     .flags         = AVFILTER_FLAG_SLICE_THREADS,
 };