/*
  * Copyright (c) 2013 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/avassert.h"

 #include "libavutil/eval.h"
 #include "libavutil/opt.h"
 #include "libavutil/pixdesc.h"
 #include "avfilter.h"

 #include "filters.h"

 #include "formats.h"
 #include "internal.h"
 #include "video.h"
 #include "libswscale/swscale.h"
 
 static const char *const var_names[] = {
     "in_w",   "iw",
     "in_h",   "ih",
     "out_w",  "ow",
     "out_h",  "oh",
     "in",
     "on",
     "duration",
     "pduration",
     "time",
     "frame",
     "zoom",
     "pzoom",
     "x", "px",
     "y", "py",
     "a",
     "sar",
     "dar",
     "hsub",
     "vsub",
     NULL
 };
 
 enum var_name {
     VAR_IN_W,   VAR_IW,
     VAR_IN_H,   VAR_IH,
     VAR_OUT_W,  VAR_OW,
     VAR_OUT_H,  VAR_OH,
     VAR_IN,
     VAR_ON,
     VAR_DURATION,
     VAR_PDURATION,
     VAR_TIME,
     VAR_FRAME,
     VAR_ZOOM,
     VAR_PZOOM,
     VAR_X, VAR_PX,
     VAR_Y, VAR_PY,
     VAR_A,
     VAR_SAR,
     VAR_DAR,
     VAR_HSUB,
     VAR_VSUB,
     VARS_NB
 };
 
 typedef struct ZPcontext {
     const AVClass *class;
     char *zoom_expr_str;
     char *x_expr_str;
     char *y_expr_str;
     char *duration_expr_str;

 
     AVExpr *zoom_expr, *x_expr, *y_expr;
 

     int w, h;
     double x, y;
     double prev_zoom;
     int prev_nb_frames;
     struct SwsContext *sws;
     int64_t frame_count;

     const AVPixFmtDescriptor *desc;
     AVFrame *in;
     double var_values[VARS_NB];
     int nb_frames;
     int current_frame;
     int finished;

     AVRational framerate;

 } ZPContext;
 
 #define OFFSET(x) offsetof(ZPContext, x)
 #define FLAGS AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
 static const AVOption zoompan_options[] = {
     { "zoom", "set the zoom expression", OFFSET(zoom_expr_str), AV_OPT_TYPE_STRING, {.str = "1" }, .flags = FLAGS },
     { "z", "set the zoom expression", OFFSET(zoom_expr_str), AV_OPT_TYPE_STRING, {.str = "1" }, .flags = FLAGS },
     { "x", "set the x expression", OFFSET(x_expr_str), AV_OPT_TYPE_STRING, {.str="0"}, .flags = FLAGS },
     { "y", "set the y expression", OFFSET(y_expr_str), AV_OPT_TYPE_STRING, {.str="0"}, .flags = FLAGS },
     { "d", "set the duration expression", OFFSET(duration_expr_str), AV_OPT_TYPE_STRING, {.str="90"}, .flags = FLAGS },
     { "s", "set the output image size", OFFSET(w), AV_OPT_TYPE_IMAGE_SIZE, {.str="hd720"}, .flags = FLAGS },

     { "fps", "set the output framerate", OFFSET(framerate), AV_OPT_TYPE_VIDEO_RATE, { .str = "25" }, 0, INT_MAX, .flags = FLAGS },

     { NULL }
 };
 
 AVFILTER_DEFINE_CLASS(zoompan);
 
 static av_cold int init(AVFilterContext *ctx)
 {
     ZPContext *s = ctx->priv;
 
     s->prev_zoom = 1;
     return 0;
 }
 
 static int config_output(AVFilterLink *outlink)
 {
     AVFilterContext *ctx = outlink->src;
     ZPContext *s = ctx->priv;

     int ret;

 
     outlink->w = s->w;
     outlink->h = s->h;

     outlink->time_base = av_inv_q(s->framerate);
     outlink->frame_rate = s->framerate;

     s->desc = av_pix_fmt_desc_get(outlink->format);

     s->finished = 1;

     ret = av_expr_parse(&s->zoom_expr, s->zoom_expr_str, var_names, NULL, NULL, NULL, NULL, 0, ctx);
     if (ret < 0)
         return ret;
 
     ret = av_expr_parse(&s->x_expr, s->x_expr_str, var_names, NULL, NULL, NULL, NULL, 0, ctx);
     if (ret < 0)
         return ret;
 
     ret = av_expr_parse(&s->y_expr, s->y_expr_str, var_names, NULL, NULL, NULL, NULL, 0, ctx);
     if (ret < 0)
         return ret;
 

     return 0;
 }
 

 static int output_single_frame(AVFilterContext *ctx, AVFrame *in, double *var_values, int i,
                                double *zoom, double *dx, double *dy)

 {
     ZPContext *s = ctx->priv;

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

     int64_t pts = s->frame_count;

     int k, x, y, w, h, ret = 0;
     uint8_t *input[4];
     int px[4], py[4];
     AVFrame *out;
 

     var_values[VAR_PX]    = s->x;
     var_values[VAR_PY]    = s->y;
     var_values[VAR_PZOOM] = s->prev_zoom;
     var_values[VAR_PDURATION] = s->prev_nb_frames;

     var_values[VAR_TIME] = pts * av_q2d(outlink->time_base);
     var_values[VAR_FRAME] = i;

     var_values[VAR_ON] = outlink->frame_count_in + 1;

 
     *zoom = av_expr_eval(s->zoom_expr, var_values, NULL);

     *zoom = av_clipd(*zoom, 1, 10);
     var_values[VAR_ZOOM] = *zoom;
     w = in->width * (1.0 / *zoom);
     h = in->height * (1.0 / *zoom);
 

     *dx = av_expr_eval(s->x_expr, var_values, NULL);
 

     x = *dx = av_clipd(*dx, 0, FFMAX(in->width - w, 0));
     var_values[VAR_X] = *dx;
     x &= ~((1 << s->desc->log2_chroma_w) - 1);

     *dy = av_expr_eval(s->y_expr, var_values, NULL);
 

     y = *dy = av_clipd(*dy, 0, FFMAX(in->height - h, 0));
     var_values[VAR_Y] = *dy;
     y &= ~((1 << s->desc->log2_chroma_h) - 1);
 
     out = ff_get_video_buffer(outlink, outlink->w, outlink->h);
     if (!out) {
         ret = AVERROR(ENOMEM);
         return ret;
     }

     px[1] = px[2] = AV_CEIL_RSHIFT(x, s->desc->log2_chroma_w);

     px[0] = px[3] = x;

     py[1] = py[2] = AV_CEIL_RSHIFT(y, s->desc->log2_chroma_h);

     py[0] = py[3] = y;

     s->sws = sws_alloc_context();
     if (!s->sws) {
         ret = AVERROR(ENOMEM);

         goto error;

     }

     for (k = 0; in->data[k]; k++)
         input[k] = in->data[k] + py[k] * in->linesize[k] + px[k];

     av_opt_set_int(s->sws, "srcw", w, 0);
     av_opt_set_int(s->sws, "srch", h, 0);
     av_opt_set_int(s->sws, "src_format", in->format, 0);
     av_opt_set_int(s->sws, "dstw", outlink->w, 0);
     av_opt_set_int(s->sws, "dsth", outlink->h, 0);
     av_opt_set_int(s->sws, "dst_format", outlink->format, 0);
     av_opt_set_int(s->sws, "sws_flags", SWS_BICUBIC, 0);

     if ((ret = sws_init_context(s->sws, NULL, NULL)) < 0)

         goto error;

     sws_scale(s->sws, (const uint8_t *const *)&input, in->linesize, 0, h, out->data, out->linesize);

     out->pts = pts;
     s->frame_count++;

     ret = ff_filter_frame(outlink, out);
     sws_freeContext(s->sws);
     s->sws = NULL;
     s->current_frame++;

 
     if (s->current_frame >= s->nb_frames) {
         if (*dx != -1)
             s->x = *dx;
         if (*dy != -1)
             s->y = *dy;
         if (*zoom != -1)
             s->prev_zoom = *zoom;
         s->prev_nb_frames = s->nb_frames;
         s->nb_frames = 0;
         s->current_frame = 0;
         av_frame_free(&s->in);
         s->finished = 1;
     }

     return ret;

 error:
     av_frame_free(&out);
     return ret;

 }

 static int activate(AVFilterContext *ctx)

 {
     ZPContext *s = ctx->priv;

     AVFilterLink *inlink = ctx->inputs[0];
     AVFilterLink *outlink = ctx->outputs[0];
     int status, ret = 0;
     int64_t pts;

     if (s->in && ff_outlink_frame_wanted(outlink)) {
         double zoom = -1, dx = -1, dy = -1;

         ret = output_single_frame(ctx, s->in, s->var_values, s->current_frame,

                                   &zoom, &dx, &dy);
         if (ret < 0)

             return ret;

     }
 

     if (!s->in && (ret = ff_inlink_consume_frame(inlink, &s->in)) > 0) {
         double zoom = -1, dx = -1, dy = -1, nb_frames;
 
         s->finished = 0;
         s->var_values[VAR_IN_W]  = s->var_values[VAR_IW] = s->in->width;
         s->var_values[VAR_IN_H]  = s->var_values[VAR_IH] = s->in->height;
         s->var_values[VAR_OUT_W] = s->var_values[VAR_OW] = s->w;
         s->var_values[VAR_OUT_H] = s->var_values[VAR_OH] = s->h;
         s->var_values[VAR_IN]    = inlink->frame_count_out + 1;
         s->var_values[VAR_ON]    = outlink->frame_count_in + 1;
         s->var_values[VAR_PX]    = s->x;
         s->var_values[VAR_PY]    = s->y;
         s->var_values[VAR_X]     = 0;
         s->var_values[VAR_Y]     = 0;
         s->var_values[VAR_PZOOM] = s->prev_zoom;
         s->var_values[VAR_ZOOM]  = 1;
         s->var_values[VAR_PDURATION] = s->prev_nb_frames;
         s->var_values[VAR_A]     = (double) s->in->width / s->in->height;
         s->var_values[VAR_SAR]   = inlink->sample_aspect_ratio.num ?
             (double) inlink->sample_aspect_ratio.num / inlink->sample_aspect_ratio.den : 1;
         s->var_values[VAR_DAR]   = s->var_values[VAR_A] * s->var_values[VAR_SAR];
         s->var_values[VAR_HSUB]  = 1 << s->desc->log2_chroma_w;
         s->var_values[VAR_VSUB]  = 1 << s->desc->log2_chroma_h;
 
         if ((ret = av_expr_parse_and_eval(&nb_frames, s->duration_expr_str,
                                           var_names, s->var_values,
                                           NULL, NULL, NULL, NULL, NULL, 0, ctx)) < 0) {
             av_frame_free(&s->in);
             return ret;
         }
 
         s->var_values[VAR_DURATION] = s->nb_frames = nb_frames;
 
         ret = output_single_frame(ctx, s->in, s->var_values, s->current_frame,
                                   &zoom, &dx, &dy);
         if (ret < 0)
             return ret;
     }
     if (ret < 0) {
         return ret;
     } else if (s->finished && ff_inlink_acknowledge_status(inlink, &status, &pts)) {
         ff_outlink_set_status(outlink, status, pts);
         return 0;
     } else {
         if (ff_outlink_frame_wanted(outlink) && s->finished)
             ff_inlink_request_frame(inlink);
         return 0;

     }
 }
 

 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_YUVA444P, AV_PIX_FMT_YUVA422P,
         AV_PIX_FMT_YUVA420P,
         AV_PIX_FMT_YUVJ444P, AV_PIX_FMT_YUVJ440P,
         AV_PIX_FMT_YUVJ422P, AV_PIX_FMT_YUVJ420P,
         AV_PIX_FMT_YUVJ411P,

         AV_PIX_FMT_GBRP, AV_PIX_FMT_GBRAP,

         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 av_cold void uninit(AVFilterContext *ctx)
 {
     ZPContext *s = ctx->priv;
 
     sws_freeContext(s->sws);
     s->sws = NULL;
 }
 
 static const AVFilterPad inputs[] = {
     {
         .name         = "default",
         .type         = AVMEDIA_TYPE_VIDEO,
     },
     { NULL }
 };
 
 static const AVFilterPad outputs[] = {
     {
         .name          = "default",
         .type          = AVMEDIA_TYPE_VIDEO,
         .config_props  = config_output,
     },
     { NULL }
 };
 
 AVFilter ff_vf_zoompan = {
     .name          = "zoompan",
     .description   = NULL_IF_CONFIG_SMALL("Apply Zoom & Pan effect."),
     .priv_size     = sizeof(ZPContext),
     .priv_class    = &zoompan_class,
     .init          = init,
     .uninit        = uninit,
     .query_formats = query_formats,

     .activate      = activate,

     .inputs        = inputs,
     .outputs       = outputs,
 };