/*
  * Copyright (c) 2016 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
  */
 
 /**
  * @file
  * filter for manipulating frame metadata
  */
 

 #include <float.h>
 

 #include "libavutil/avassert.h"
 #include "libavutil/avstring.h"
 #include "libavutil/eval.h"
 #include "libavutil/internal.h"
 #include "libavutil/opt.h"

 #include "libavutil/timestamp.h"

 #include "libavformat/avio.h"

 #include "avfilter.h"
 #include "audio.h"
 #include "formats.h"
 #include "internal.h"
 #include "video.h"
 
 enum MetadataMode {
     METADATA_SELECT,
     METADATA_ADD,
     METADATA_MODIFY,
     METADATA_DELETE,
     METADATA_PRINT,
     METADATA_NB
 };
 
 enum MetadataFunction {

     METADATAF_SAME_STR,

     METADATAF_STARTS_WITH,

     METADATAF_LESS,
     METADATAF_EQUAL,
     METADATAF_GREATER,
     METADATAF_EXPR,
     METADATAF_NB
 };
 
 static const char *const var_names[] = {
     "VALUE1",
     "VALUE2",
     NULL
 };
 
 enum var_name {
     VAR_VALUE1,
     VAR_VALUE2,
     VAR_VARS_NB
 };
 
 typedef struct MetadataContext {
     const AVClass *class;
 
     int mode;
     char *key;
     char *value;
     int function;
 
     char *expr_str;
     AVExpr *expr;
     double var_values[VAR_VARS_NB];
 

     AVIOContext* avio_context;

     char *file_str;
 

     int (*compare)(struct MetadataContext *s,

                    const char *value1, const char *value2);

     void (*print)(AVFilterContext *ctx, const char *msg, ...) av_printf_format(2, 3);

 } MetadataContext;
 
 #define OFFSET(x) offsetof(MetadataContext, x)

 #define DEFINE_OPTIONS(filt_name, FLAGS) \
 static const AVOption filt_name##_options[] = { \

     { "mode", "set a mode of operation", OFFSET(mode),   AV_OPT_TYPE_INT,    {.i64 = 0 }, 0, METADATA_NB-1, FLAGS, "mode" }, \
     {   "select", "select frame",        0,              AV_OPT_TYPE_CONST,  {.i64 = METADATA_SELECT }, 0, 0, FLAGS, "mode" }, \
     {   "add",    "add new metadata",    0,              AV_OPT_TYPE_CONST,  {.i64 = METADATA_ADD },    0, 0, FLAGS, "mode" }, \
     {   "modify", "modify metadata",     0,              AV_OPT_TYPE_CONST,  {.i64 = METADATA_MODIFY }, 0, 0, FLAGS, "mode" }, \
     {   "delete", "delete metadata",     0,              AV_OPT_TYPE_CONST,  {.i64 = METADATA_DELETE }, 0, 0, FLAGS, "mode" }, \
     {   "print",  "print metadata",      0,              AV_OPT_TYPE_CONST,  {.i64 = METADATA_PRINT },  0, 0, FLAGS, "mode" }, \
     { "key",   "set metadata key",       OFFSET(key),    AV_OPT_TYPE_STRING, {.str = NULL }, 0, 0, FLAGS }, \
     { "value", "set metadata value",     OFFSET(value),  AV_OPT_TYPE_STRING, {.str = NULL }, 0, 0, FLAGS }, \
     { "function", "function for comparing values", OFFSET(function), AV_OPT_TYPE_INT, {.i64 = 0 }, 0, METADATAF_NB-1, FLAGS, "function" }, \

     {   "same_str",    NULL, 0, AV_OPT_TYPE_CONST, {.i64 = METADATAF_SAME_STR },    0, 3, FLAGS, "function" }, \

     {   "starts_with", NULL, 0, AV_OPT_TYPE_CONST, {.i64 = METADATAF_STARTS_WITH }, 0, 0, FLAGS, "function" }, \

     {   "less",        NULL, 0, AV_OPT_TYPE_CONST, {.i64 = METADATAF_LESS    },     0, 3, FLAGS, "function" }, \
     {   "equal",       NULL, 0, AV_OPT_TYPE_CONST, {.i64 = METADATAF_EQUAL   },     0, 3, FLAGS, "function" }, \
     {   "greater",     NULL, 0, AV_OPT_TYPE_CONST, {.i64 = METADATAF_GREATER },     0, 3, FLAGS, "function" }, \
     {   "expr",        NULL, 0, AV_OPT_TYPE_CONST, {.i64 = METADATAF_EXPR    },     0, 3, FLAGS, "function" }, \

     { "expr", "set expression for expr function", OFFSET(expr_str), AV_OPT_TYPE_STRING, {.str = NULL }, 0, 0, FLAGS }, \

     { "file", "set file where to print metadata information", OFFSET(file_str), AV_OPT_TYPE_STRING, {.str=NULL}, 0, 0, FLAGS }, \

     { NULL } \

 }
 

 static int same_str(MetadataContext *s, const char *value1, const char *value2)

 {

     return !strcmp(value1, value2);

 }
 

 static int starts_with(MetadataContext *s, const char *value1, const char *value2)

 {
     return !strncmp(value1, value2, strlen(value2));
 }
 

 static int equal(MetadataContext *s, const char *value1, const char *value2)

 {
     float f1, f2;
 
     if (sscanf(value1, "%f", &f1) + sscanf(value2, "%f", &f2) != 2)
         return 0;
 

     return fabsf(f1 - f2) < FLT_EPSILON;

 }
 

 static int less(MetadataContext *s, const char *value1, const char *value2)

 {
     float f1, f2;
 
     if (sscanf(value1, "%f", &f1) + sscanf(value2, "%f", &f2) != 2)
         return 0;
 

     return (f1 - f2) < FLT_EPSILON;

 }
 

 static int greater(MetadataContext *s, const char *value1, const char *value2)

 {
     float f1, f2;
 
     if (sscanf(value1, "%f", &f1) + sscanf(value2, "%f", &f2) != 2)
         return 0;
 

     return (f2 - f1) < FLT_EPSILON;

 }
 

 static int parse_expr(MetadataContext *s, const char *value1, const char *value2)

 {
     double f1, f2;
 
     if (sscanf(value1, "%lf", &f1) + sscanf(value2, "%lf", &f2) != 2)
         return 0;
 
     s->var_values[VAR_VALUE1] = f1;

     s->var_values[VAR_VALUE2] = f2;

 
     return av_expr_eval(s->expr, s->var_values, NULL);
 }
 

 static void print_log(AVFilterContext *ctx, const char *msg, ...)
 {
     va_list argument_list;
 
     va_start(argument_list, msg);
     if (msg)
         av_vlog(ctx, AV_LOG_INFO, msg, argument_list);
     va_end(argument_list);
 }
 
 static void print_file(AVFilterContext *ctx, const char *msg, ...)
 {
     MetadataContext *s = ctx->priv;
     va_list argument_list;
 
     va_start(argument_list, msg);

     if (msg) {
         char buf[128];
         vsnprintf(buf, sizeof(buf), msg, argument_list);
         avio_write(s->avio_context, buf, av_strnlen(buf, sizeof(buf)));
     }

     va_end(argument_list);
 }
 

 static av_cold int init(AVFilterContext *ctx)
 {
     MetadataContext *s = ctx->priv;
     int ret;
 

     if (!s->key && s->mode != METADATA_PRINT && s->mode != METADATA_DELETE) {

         av_log(ctx, AV_LOG_WARNING, "Metadata key must be set\n");
         return AVERROR(EINVAL);
     }
 
     if ((s->mode == METADATA_MODIFY ||
         s->mode == METADATA_ADD) && !s->value) {
         av_log(ctx, AV_LOG_WARNING, "Missing metadata value\n");
         return AVERROR(EINVAL);
     }
 
     switch (s->function) {

     case METADATAF_SAME_STR:
         s->compare = same_str;

         break;

     case METADATAF_STARTS_WITH:
         s->compare = starts_with;
         break;

     case METADATAF_LESS:
         s->compare = less;
         break;
     case METADATAF_EQUAL:
         s->compare = equal;
         break;
     case METADATAF_GREATER:
         s->compare = greater;
         break;
     case METADATAF_EXPR:
         s->compare = parse_expr;
         break;
     default:
         av_assert0(0);
     };
 
     if (s->function == METADATAF_EXPR) {
         if (!s->expr_str) {
             av_log(ctx, AV_LOG_WARNING, "expr option not set\n");
             return AVERROR(EINVAL);
         }
         if ((ret = av_expr_parse(&s->expr, s->expr_str,
                                  var_names, NULL, NULL, NULL, NULL, 0, ctx)) < 0) {
             av_log(ctx, AV_LOG_ERROR, "Error while parsing expression '%s'\n", s->expr_str);
             return ret;
         }
     }
 

     if (s->mode == METADATA_PRINT && s->file_str) {

         s->print = print_file;
     } else {
         s->print = print_log;
     }
 

     s->avio_context = NULL;
     if (s->file_str) {
         if (!strcmp("-", s->file_str)) {
             ret = avio_open(&s->avio_context, "pipe:1", AVIO_FLAG_WRITE);
         } else {
             ret = avio_open(&s->avio_context, s->file_str, AVIO_FLAG_WRITE);
         }
 
         if (ret < 0) {
             char buf[128];
             av_strerror(ret, buf, sizeof(buf));
             av_log(ctx, AV_LOG_ERROR, "Could not open %s: %s\n",
                    s->file_str, buf);
             return ret;
         }
     }
 

     return 0;
 }
 

 static av_cold void uninit(AVFilterContext *ctx)
 {
     MetadataContext *s = ctx->priv;
 

     if (s->avio_context) {
         avio_closep(&s->avio_context);
     }

 }
 

 static int filter_frame(AVFilterLink *inlink, AVFrame *frame)
 {
     AVFilterContext *ctx = inlink->dst;
     AVFilterLink *outlink = ctx->outputs[0];
     MetadataContext *s = ctx->priv;

     AVDictionary **metadata = &frame->metadata;

     AVDictionaryEntry *e;
 

     if (!*metadata)

         return ff_filter_frame(outlink, frame);
 

     e = av_dict_get(*metadata, !s->key ? "" : s->key, NULL,

                     !s->key ? AV_DICT_IGNORE_SUFFIX: 0);
 
     switch (s->mode) {
     case METADATA_SELECT:
         if (!s->value && e && e->value) {
             return ff_filter_frame(outlink, frame);
         } else if (s->value && e && e->value &&

                    s->compare(s, e->value, s->value)) {

             return ff_filter_frame(outlink, frame);
         }
         break;
     case METADATA_ADD:
         if (e && e->value) {
             ;
         } else {

             av_dict_set(metadata, s->key, s->value, 0);

         }
         return ff_filter_frame(outlink, frame);
         break;
     case METADATA_MODIFY:
         if (e && e->value) {

             av_dict_set(metadata, s->key, s->value, 0);

         }
         return ff_filter_frame(outlink, frame);
         break;
     case METADATA_PRINT:
         if (!s->key && e) {

             s->print(ctx, "frame:%-4"PRId64" pts:%-7s pts_time:%s\n",

                      inlink->frame_count_out, av_ts2str(frame->pts), av_ts2timestr(frame->pts, &inlink->time_base));

             s->print(ctx, "%s=%s\n", e->key, e->value);

             while ((e = av_dict_get(*metadata, "", e, AV_DICT_IGNORE_SUFFIX)) != NULL) {

                 s->print(ctx, "%s=%s\n", e->key, e->value);

             }

         } else if (e && e->value && (!s->value || (e->value && s->compare(s, e->value, s->value)))) {

             s->print(ctx, "frame:%-4"PRId64" pts:%-7s pts_time:%s\n",

                      inlink->frame_count_out, av_ts2str(frame->pts), av_ts2timestr(frame->pts, &inlink->time_base));

             s->print(ctx, "%s=%s\n", s->key, e->value);

         }
         return ff_filter_frame(outlink, frame);
         break;
     case METADATA_DELETE:

         if (!s->key) {
             av_dict_free(metadata);

         } else if (e && e->value && (!s->value || s->compare(s, e->value, s->value))) {

             av_dict_set(metadata, s->key, NULL, 0);

         }
         return ff_filter_frame(outlink, frame);
         break;
     default:
         av_assert0(0);
     };
 
     av_frame_free(&frame);
 
     return 0;
 }
 
 #if CONFIG_AMETADATA_FILTER
 
 DEFINE_OPTIONS(ametadata, AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM);
 AVFILTER_DEFINE_CLASS(ametadata);
 
 static const AVFilterPad ainputs[] = {
     {
         .name         = "default",
         .type         = AVMEDIA_TYPE_AUDIO,
         .filter_frame = filter_frame,
     },
     { NULL }
 };
 
 static const AVFilterPad aoutputs[] = {
     {
         .name = "default",
         .type = AVMEDIA_TYPE_AUDIO,
     },
     { NULL }
 };
 
 AVFilter ff_af_ametadata = {
     .name          = "ametadata",
     .description   = NULL_IF_CONFIG_SMALL("Manipulate audio frame metadata."),
     .priv_size     = sizeof(MetadataContext),
     .priv_class    = &ametadata_class,
     .init          = init,

     .uninit        = uninit,

     .inputs        = ainputs,
     .outputs       = aoutputs,
     .flags         = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC,
 };
 #endif /* CONFIG_AMETADATA_FILTER */
 
 #if CONFIG_METADATA_FILTER
 
 DEFINE_OPTIONS(metadata, AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM);
 AVFILTER_DEFINE_CLASS(metadata);
 
 static const AVFilterPad inputs[] = {
     {
         .name         = "default",
         .type         = AVMEDIA_TYPE_VIDEO,
         .filter_frame = filter_frame,
     },
     { NULL }
 };
 
 static const AVFilterPad outputs[] = {
     {
         .name = "default",
         .type = AVMEDIA_TYPE_VIDEO,
     },
     { NULL }
 };
 
 AVFilter ff_vf_metadata = {
     .name        = "metadata",
     .description = NULL_IF_CONFIG_SMALL("Manipulate video frame metadata."),
     .priv_size   = sizeof(MetadataContext),
     .priv_class  = &metadata_class,
     .init        = init,

     .uninit      = uninit,

     .inputs      = inputs,
     .outputs     = outputs,
     .flags       = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC,
 };
 #endif /* CONFIG_METADATA_FILTER */