/*
  * Copyright (c) 2013 Clément Bœsch
  *
  * 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 <float.h>  /* DBL_MAX */
 

 #include "libavutil/opt.h"
 #include "libavutil/eval.h"
 #include "libavutil/avassert.h"
 #include "libavutil/pixdesc.h"
 #include "avfilter.h"
 #include "formats.h"
 #include "internal.h"
 #include "video.h"
 
 static const char *const var_names[] = {
     "w",    // stream width
     "h",    // stream height
     "n",    // frame count
     "pts",  // presentation timestamp expressed in AV_TIME_BASE units
     "r",    // frame rate
     "t",    // timestamp expressed in seconds
     "tb",   // timebase
     NULL
 };
 
 enum var_name {
     VAR_W,
     VAR_H,
     VAR_N,
     VAR_PTS,
     VAR_R,
     VAR_T,
     VAR_TB,
     VAR_NB
 };
 

 enum EvalMode {
     EVAL_MODE_INIT,
     EVAL_MODE_FRAME,
     EVAL_MODE_NB
 };
 

 typedef struct VignetteContext {

     const AVClass *class;
     const AVPixFmtDescriptor *desc;
     int backward;

     int eval_mode;                      ///< EvalMode

 #define DEF_EXPR_FIELDS(name) AVExpr *name##_pexpr; char *name##_expr; double name

     DEF_EXPR_FIELDS(angle);
     DEF_EXPR_FIELDS(x0);
     DEF_EXPR_FIELDS(y0);
     double var_values[VAR_NB];
     float *fmap;
     int fmap_linesize;
     double dmax;
     float xscale, yscale;
     uint32_t dither;
     int do_dither;

     AVRational aspect;
     AVRational scale;

 } VignetteContext;
 
 #define OFFSET(x) offsetof(VignetteContext, x)
 #define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
 static const AVOption vignette_options[] = {
     { "angle", "set lens angle", OFFSET(angle_expr), AV_OPT_TYPE_STRING, {.str="PI/5"}, .flags = FLAGS },
     { "a",     "set lens angle", OFFSET(angle_expr), AV_OPT_TYPE_STRING, {.str="PI/5"}, .flags = FLAGS },
     { "x0", "set circle center position on x-axis", OFFSET(x0_expr), AV_OPT_TYPE_STRING, {.str="w/2"}, .flags = FLAGS },
     { "y0", "set circle center position on y-axis", OFFSET(y0_expr), AV_OPT_TYPE_STRING, {.str="h/2"}, .flags = FLAGS },
     { "mode", "set forward/backward mode", OFFSET(backward), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 1, FLAGS, "mode" },
         { "forward",  NULL, 0, AV_OPT_TYPE_CONST, {.i64 = 0}, INT_MIN, INT_MAX, FLAGS, "mode"},
         { "backward", NULL, 0, AV_OPT_TYPE_CONST, {.i64 = 1}, INT_MIN, INT_MAX, FLAGS, "mode"},
     { "eval", "specify when to evaluate expressions", OFFSET(eval_mode), AV_OPT_TYPE_INT, {.i64 = EVAL_MODE_INIT}, 0, EVAL_MODE_NB-1, FLAGS, "eval" },
          { "init",  "eval expressions once during initialization", 0, AV_OPT_TYPE_CONST, {.i64=EVAL_MODE_INIT},  .flags = FLAGS, .unit = "eval" },
          { "frame", "eval expressions for each frame",             0, AV_OPT_TYPE_CONST, {.i64=EVAL_MODE_FRAME}, .flags = FLAGS, .unit = "eval" },

     { "dither", "set dithering", OFFSET(do_dither), AV_OPT_TYPE_BOOL, {.i64 = 1}, 0, 1, FLAGS },

     { "aspect", "set aspect ratio", OFFSET(aspect), AV_OPT_TYPE_RATIONAL, {.dbl = 1}, 0, DBL_MAX, .flags = FLAGS },

     { NULL }
 };
 
 AVFILTER_DEFINE_CLASS(vignette);
 
 static av_cold int init(AVFilterContext *ctx)
 {
     VignetteContext *s = ctx->priv;
 
 #define PARSE_EXPR(name) do {                                               \
     int ret = av_expr_parse(&s->name##_pexpr,  s->name##_expr, var_names,   \
                             NULL, NULL, NULL, NULL, 0, ctx);                \
     if (ret < 0) {                                                          \
         av_log(ctx, AV_LOG_ERROR, "Unable to parse expression for '"        \
                AV_STRINGIFY(name) "'\n");                                   \
         return ret;                                                         \
     }                                                                       \
 } while (0)
 
     PARSE_EXPR(angle);
     PARSE_EXPR(x0);
     PARSE_EXPR(y0);
     return 0;
 }
 
 static av_cold void uninit(AVFilterContext *ctx)
 {
     VignetteContext *s = ctx->priv;
     av_freep(&s->fmap);
     av_expr_free(s->angle_pexpr);
     av_expr_free(s->x0_pexpr);
     av_expr_free(s->y0_pexpr);
 }
 
 static int query_formats(AVFilterContext *ctx)
 {
     static const enum AVPixelFormat pix_fmts[] = {
         AV_PIX_FMT_YUV444P, AV_PIX_FMT_YUV422P,
         AV_PIX_FMT_YUV420P, AV_PIX_FMT_YUV411P,
         AV_PIX_FMT_YUV410P, AV_PIX_FMT_YUV440P,
         AV_PIX_FMT_RGB24,   AV_PIX_FMT_BGR24,
         AV_PIX_FMT_GRAY8,
         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 double get_natural_factor(const VignetteContext *s, int x, int y)
 {
     const int xx = (x - s->x0) * s->xscale;
     const int yy = (y - s->y0) * s->yscale;
     const double dnorm = hypot(xx, yy) / s->dmax;
     if (dnorm > 1) {
         return 0;
     } else {
         const double c = cos(s->angle * dnorm);
         return (c*c)*(c*c); // do not remove braces, it helps compilers
     }
 }
 
 #define TS2D(ts)     ((ts) == AV_NOPTS_VALUE ? NAN : (double)(ts))
 #define TS2T(ts, tb) ((ts) == AV_NOPTS_VALUE ? NAN : (double)(ts) * av_q2d(tb))
 
 static void update_context(VignetteContext *s, AVFilterLink *inlink, AVFrame *frame)
 {
     int x, y;
     float *dst = s->fmap;
     int dst_linesize = s->fmap_linesize;
 
     if (frame) {

         s->var_values[VAR_N]   = inlink->frame_count_out;

         s->var_values[VAR_T]   = TS2T(frame->pts, inlink->time_base);
         s->var_values[VAR_PTS] = TS2D(frame->pts);
     } else {

         s->var_values[VAR_N]   = NAN;

         s->var_values[VAR_T]   = NAN;
         s->var_values[VAR_PTS] = NAN;
     }
 

     s->angle = av_expr_eval(s->angle_pexpr, s->var_values, NULL);

     s->x0 = av_expr_eval(s->x0_pexpr, s->var_values, NULL);
     s->y0 = av_expr_eval(s->y0_pexpr, s->var_values, NULL);
 

     if (isnan(s->x0) || isnan(s->y0) || isnan(s->angle))
         s->eval_mode = EVAL_MODE_FRAME;
 
     s->angle = av_clipf(s->angle, 0, M_PI_2);
 

     if (s->backward) {
         for (y = 0; y < inlink->h; y++) {
             for (x = 0; x < inlink->w; x++)
                 dst[x] = 1. / get_natural_factor(s, x, y);
             dst += dst_linesize;
         }
     } else {
         for (y = 0; y < inlink->h; y++) {
             for (x = 0; x < inlink->w; x++)
                 dst[x] = get_natural_factor(s, x, y);
             dst += dst_linesize;
         }
     }
 }
 
 static inline double get_dither_value(VignetteContext *s)
 {
     double dv = 0;
     if (s->do_dither) {
         dv = s->dither / (double)(1LL<<32);
         s->dither = s->dither * 1664525 + 1013904223;
     }
     return dv;
 }
 
 static int filter_frame(AVFilterLink *inlink, AVFrame *in)
 {

     unsigned x, y, direct = 0;

     AVFilterContext *ctx = inlink->dst;
     VignetteContext *s = ctx->priv;

     AVFilterLink *outlink = ctx->outputs[0];

     AVFrame *out;
 

     if (av_frame_is_writable(in)) {
         direct = 1;
         out = in;
     } else {

         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);

     }

 
     if (s->eval_mode == EVAL_MODE_FRAME)
         update_context(s, inlink, in);
 

     if (s->desc->flags & AV_PIX_FMT_FLAG_RGB) {

         uint8_t       *dst = out->data[0];
         const uint8_t *src = in ->data[0];
         const float *fmap = s->fmap;
         const int dst_linesize = out->linesize[0];
         const int src_linesize = in ->linesize[0];
         const int fmap_linesize = s->fmap_linesize;
 
         for (y = 0; y < inlink->h; y++) {
             uint8_t       *dstp = dst;
             const uint8_t *srcp = src;
 
             for (x = 0; x < inlink->w; x++, dstp += 3, srcp += 3) {
                 const float f = fmap[x];
 
                 dstp[0] = av_clip_uint8(srcp[0] * f + get_dither_value(s));
                 dstp[1] = av_clip_uint8(srcp[1] * f + get_dither_value(s));
                 dstp[2] = av_clip_uint8(srcp[2] * f + get_dither_value(s));
             }
             dst += dst_linesize;
             src += src_linesize;
             fmap += fmap_linesize;
         }
     } else {
         int plane;
 

         for (plane = 0; plane < 4 && in->data[plane] && in->linesize[plane]; plane++) {

             uint8_t       *dst = out->data[plane];
             const uint8_t *src = in ->data[plane];
             const float *fmap = s->fmap;
             const int dst_linesize = out->linesize[plane];
             const int src_linesize = in ->linesize[plane];
             const int fmap_linesize = s->fmap_linesize;
             const int chroma = plane == 1 || plane == 2;
             const int hsub = chroma ? s->desc->log2_chroma_w : 0;
             const int vsub = chroma ? s->desc->log2_chroma_h : 0;

             const int w = AV_CEIL_RSHIFT(inlink->w, hsub);
             const int h = AV_CEIL_RSHIFT(inlink->h, vsub);

 
             for (y = 0; y < h; y++) {
                 uint8_t *dstp = dst;
                 const uint8_t *srcp = src;
 
                 for (x = 0; x < w; x++) {
                     const double dv = get_dither_value(s);
                     if (chroma) *dstp++ = av_clip_uint8(fmap[x << hsub] * (*srcp++ - 127) + 127 + dv);
                     else        *dstp++ = av_clip_uint8(fmap[x        ] *  *srcp++              + dv);
                 }
                 dst += dst_linesize;
                 src += src_linesize;
                 fmap += fmap_linesize << vsub;
             }
         }
     }
 

     if (!direct)
         av_frame_free(&in);

     return ff_filter_frame(outlink, out);
 }
 
 static int config_props(AVFilterLink *inlink)
 {
     VignetteContext *s = inlink->dst->priv;

     AVRational sar = inlink->sample_aspect_ratio;

 
     s->desc = av_pix_fmt_desc_get(inlink->format);
     s->var_values[VAR_W]  = inlink->w;
     s->var_values[VAR_H]  = inlink->h;
     s->var_values[VAR_TB] = av_q2d(inlink->time_base);
     s->var_values[VAR_R]  = inlink->frame_rate.num == 0 || inlink->frame_rate.den == 0 ?
         NAN : av_q2d(inlink->frame_rate);
 

     if (!sar.num || !sar.den)
         sar.num = sar.den = 1;
     if (sar.num > sar.den) {

         s->xscale = av_q2d(av_div_q(sar, s->aspect));

         s->yscale = 1;
     } else {

         s->yscale = av_q2d(av_div_q(s->aspect, sar));

         s->xscale = 1;
     }

     s->dmax = hypot(inlink->w / 2., inlink->h / 2.);

     av_log(s, AV_LOG_DEBUG, "xscale=%f yscale=%f dmax=%f\n",
            s->xscale, s->yscale, s->dmax);

 
     s->fmap_linesize = FFALIGN(inlink->w, 32);

     s->fmap = av_malloc_array(s->fmap_linesize, inlink->h * sizeof(*s->fmap));

     if (!s->fmap)
         return AVERROR(ENOMEM);
 
     if (s->eval_mode == EVAL_MODE_INIT)
         update_context(s, inlink, NULL);
 
     return 0;
 }
 
 static const AVFilterPad vignette_inputs[] = {
     {
         .name         = "default",
         .type         = AVMEDIA_TYPE_VIDEO,
         .filter_frame = filter_frame,
         .config_props = config_props,
     },
     { NULL }
 };
 
 static const AVFilterPad vignette_outputs[] = {

     {
         .name = "default",
         .type = AVMEDIA_TYPE_VIDEO,
     },
     { NULL }

 };
 

 AVFilter ff_vf_vignette = {

     .name          = "vignette",
     .description   = NULL_IF_CONFIG_SMALL("Make or reverse a vignette effect."),
     .priv_size     = sizeof(VignetteContext),
     .init          = init,
     .uninit        = uninit,
     .query_formats = query_formats,
     .inputs        = vignette_inputs,
     .outputs       = vignette_outputs,
     .priv_class    = &vignette_class,
     .flags         = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC,
 };