/*
  * Copyright (c) 2011 Stefano Sabatini
  *
  * 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
  * eval audio source
  */
 
 #include "libavutil/avassert.h"
 #include "libavutil/avstring.h"

 #include "libavutil/channel_layout.h"

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

 #include "libavutil/parseutils.h"

 #include "avfilter.h"

 #include "audio.h"

 #include "internal.h"
 

 static const char * const var_names[] = {

     "ch",           ///< the value of the current channel

     "n",            ///< number of frame

     "nb_in_channels",
     "nb_out_channels",

     "t",            ///< timestamp expressed in seconds
     "s",            ///< sample rate
     NULL
 };
 
 enum var_name {

     VAR_CH,

     VAR_N,

     VAR_NB_IN_CHANNELS,
     VAR_NB_OUT_CHANNELS,

     VAR_T,
     VAR_S,
     VAR_VARS_NB
 };
 

 typedef struct EvalContext {

     const AVClass *class;
     char *sample_rate_str;
     int sample_rate;
     int64_t chlayout;

     char *chlayout_str;

     int nb_channels;            ///< number of output channels
     int nb_in_channels;         ///< number of input channels
     int same_chlayout;          ///< set output as input channel layout

     int64_t pts;

     AVExpr **expr;

     char *exprs;

     int nb_samples;             ///< number of samples per requested frame

     int64_t duration;

     uint64_t n;
     double var_values[VAR_VARS_NB];

     double *channel_values;
     int64_t out_channel_layout;

 } EvalContext;
 

 static double val(void *priv, double ch)
 {
     EvalContext *eval = priv;
     return eval->channel_values[FFMIN((int)ch, eval->nb_in_channels-1)];
 }
 
 static double (* const aeval_func1[])(void *, double) = { val, NULL };
 static const char * const aeval_func1_names[] = { "val", NULL };
 

 #define OFFSET(x) offsetof(EvalContext, x)

 #define FLAGS AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM

 static const AVOption aevalsrc_options[]= {

     { "exprs",       "set the '|'-separated list of channels expressions", OFFSET(exprs), AV_OPT_TYPE_STRING, {.str = NULL}, .flags = FLAGS },

     { "nb_samples",  "set the number of samples per requested frame", OFFSET(nb_samples),      AV_OPT_TYPE_INT,    {.i64 = 1024},    0,        INT_MAX, FLAGS },
     { "n",           "set the number of samples per requested frame", OFFSET(nb_samples),      AV_OPT_TYPE_INT,    {.i64 = 1024},    0,        INT_MAX, FLAGS },

     { "sample_rate", "set the sample rate",                           OFFSET(sample_rate_str), AV_OPT_TYPE_STRING, {.str = "44100"}, CHAR_MIN, CHAR_MAX, FLAGS },
     { "s",           "set the sample rate",                           OFFSET(sample_rate_str), AV_OPT_TYPE_STRING, {.str = "44100"}, CHAR_MIN, CHAR_MAX, FLAGS },

     { "duration",    "set audio duration", OFFSET(duration), AV_OPT_TYPE_DURATION, {.i64 = -1}, -1, INT64_MAX, FLAGS },
     { "d",           "set audio duration", OFFSET(duration), AV_OPT_TYPE_DURATION, {.i64 = -1}, -1, INT64_MAX, FLAGS },

     { "channel_layout", "set channel layout", OFFSET(chlayout_str), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, FLAGS },
     { "c",              "set channel layout", OFFSET(chlayout_str), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, FLAGS },

     { NULL }

 };
 

 AVFILTER_DEFINE_CLASS(aevalsrc);

 static int parse_channel_expressions(AVFilterContext *ctx,
                                      int expected_nb_channels)

 {
     EvalContext *eval = ctx->priv;

     char *args1 = av_strdup(eval->exprs);

     char *expr, *last_expr = NULL, *buf;

     double (* const *func1)(void *, double) = NULL;
     const char * const *func1_names = NULL;
     int i, ret = 0;
 
     if (!args1)
         return AVERROR(ENOMEM);

     if (!eval->exprs) {

         av_log(ctx, AV_LOG_ERROR, "Channels expressions list is empty\n");

         return AVERROR(EINVAL);
     }
 
     if (!strcmp(ctx->filter->name, "aeval")) {
         func1 = aeval_func1;
         func1_names = aeval_func1_names;

     }
 

 #define ADD_EXPRESSION(expr_) do {                                      \
         if (!av_dynarray2_add((void **)&eval->expr, &eval->nb_channels, \
                               sizeof(*eval->expr), NULL)) {             \
             ret = AVERROR(ENOMEM);                                      \
             goto end;                                                   \
         }                                                               \
         eval->expr[eval->nb_channels-1] = NULL;                         \
         ret = av_expr_parse(&eval->expr[eval->nb_channels - 1], expr_,  \

                             var_names, func1_names, func1,              \

                             NULL, NULL, 0, ctx);                        \
         if (ret < 0)                                                    \
             goto end;                                                   \
     } while (0)
 

     /* reset expressions */
     for (i = 0; i < eval->nb_channels; i++) {
         av_expr_free(eval->expr[i]);
         eval->expr[i] = NULL;
     }
     av_freep(&eval->expr);
     eval->nb_channels = 0;
 

     buf = args1;

     while (expr = av_strtok(buf, "|", &buf)) {

         ADD_EXPRESSION(expr);
         last_expr = expr;

     }

     if (expected_nb_channels > eval->nb_channels)
         for (i = eval->nb_channels; i < expected_nb_channels; i++)
             ADD_EXPRESSION(last_expr);
 
     if (expected_nb_channels > 0 && eval->nb_channels != expected_nb_channels) {
         av_log(ctx, AV_LOG_ERROR,
                "Mismatch between the specified number of channel expressions '%d' "
                "and the number of expected output channels '%d' for the specified channel layout\n",
                eval->nb_channels, expected_nb_channels);
         ret = AVERROR(EINVAL);
         goto end;
     }
 
 end:
     av_free(args1);
     return ret;
 }

 static av_cold int init(AVFilterContext *ctx)
 {
     EvalContext *eval = ctx->priv;

     int ret = 0;

 
     if (eval->chlayout_str) {
         if (!strcmp(eval->chlayout_str, "same") && !strcmp(ctx->filter->name, "aeval")) {
             eval->same_chlayout = 1;
         } else {
             ret = ff_parse_channel_layout(&eval->chlayout, NULL, eval->chlayout_str, ctx);
             if (ret < 0)
                 return ret;
 
             ret = parse_channel_expressions(ctx, av_get_channel_layout_nb_channels(eval->chlayout));
             if (ret < 0)
                 return ret;

         }
     } else {

         /* guess channel layout from nb expressions/channels */

         if ((ret = parse_channel_expressions(ctx, -1)) < 0)
             return ret;
 

         eval->chlayout = av_get_default_channel_layout(eval->nb_channels);

         if (!eval->chlayout && eval->nb_channels <= 0) {

             av_log(ctx, AV_LOG_ERROR, "Invalid number of channels '%d' provided\n",
                    eval->nb_channels);

             return AVERROR(EINVAL);

         }

     }

     if (eval->sample_rate_str)
         if ((ret = ff_parse_sample_rate(&eval->sample_rate, eval->sample_rate_str, ctx)))
             return ret;

     eval->n = 0;
 
     return ret;
 }
 

 static av_cold void uninit(AVFilterContext *ctx)

 {
     EvalContext *eval = ctx->priv;
     int i;
 

     for (i = 0; i < eval->nb_channels; i++) {

         av_expr_free(eval->expr[i]);
         eval->expr[i] = NULL;
     }

     av_freep(&eval->expr);

     av_freep(&eval->channel_values);

 }
 
 static int config_props(AVFilterLink *outlink)
 {
     EvalContext *eval = outlink->src->priv;
     char buf[128];
 
     outlink->time_base = (AVRational){1, eval->sample_rate};
     outlink->sample_rate = eval->sample_rate;
 
     eval->var_values[VAR_S] = eval->sample_rate;

     eval->var_values[VAR_NB_IN_CHANNELS] = NAN;
     eval->var_values[VAR_NB_OUT_CHANNELS] = outlink->channels;

 
     av_get_channel_layout_string(buf, sizeof(buf), 0, eval->chlayout);
 

     av_log(outlink->src, AV_LOG_VERBOSE,

            "sample_rate:%d chlayout:%s duration:%"PRId64"\n",

            eval->sample_rate, buf, eval->duration);

 
     return 0;
 }
 
 static int query_formats(AVFilterContext *ctx)
 {
     EvalContext *eval = ctx->priv;

     static const enum AVSampleFormat sample_fmts[] = { AV_SAMPLE_FMT_DBLP, AV_SAMPLE_FMT_NONE };

     int64_t chlayouts[] = { eval->chlayout ? eval->chlayout : FF_COUNT2LAYOUT(eval->nb_channels) , -1 };

     int sample_rates[] = { eval->sample_rate, -1 };

     AVFilterFormats *formats;
     AVFilterChannelLayouts *layouts;
     int ret;

     formats = ff_make_format_list(sample_fmts);
     if (!formats)
         return AVERROR(ENOMEM);
     ret = ff_set_common_formats (ctx, formats);
     if (ret < 0)
         return ret;

     layouts = avfilter_make_format64_list(chlayouts);
     if (!layouts)
         return AVERROR(ENOMEM);
     ret = ff_set_common_channel_layouts(ctx, layouts);
     if (ret < 0)
         return ret;
 
     formats = ff_make_format_list(sample_rates);
     if (!formats)
         return AVERROR(ENOMEM);
     return ff_set_common_samplerates(ctx, formats);

 }
 
 static int request_frame(AVFilterLink *outlink)
 {
     EvalContext *eval = outlink->src->priv;

     AVFrame *samplesref;

     int i, j;

     int64_t t = av_rescale(eval->n, AV_TIME_BASE, eval->sample_rate);

     int nb_samples;

     if (eval->duration >= 0 && t >= eval->duration)

         return AVERROR_EOF;

     if (eval->duration >= 0) {
         nb_samples = FFMIN(eval->nb_samples, av_rescale(eval->duration, eval->sample_rate, AV_TIME_BASE) - eval->pts);
         if (!nb_samples)
             return AVERROR_EOF;
     } else {
         nb_samples = eval->nb_samples;
     }
     samplesref = ff_get_audio_buffer(outlink, nb_samples);

     if (!samplesref)
         return AVERROR(ENOMEM);

 
     /* evaluate expression for each single sample and for each channel */

     for (i = 0; i < nb_samples; i++, eval->n++) {

         eval->var_values[VAR_N] = eval->n;
         eval->var_values[VAR_T] = eval->var_values[VAR_N] * (double)1/eval->sample_rate;
 
         for (j = 0; j < eval->nb_channels; j++) {

             *((double *) samplesref->extended_data[j] + i) =

                 av_expr_eval(eval->expr[j], eval->var_values, NULL);
         }
     }
 
     samplesref->pts = eval->pts;

     samplesref->sample_rate = eval->sample_rate;

     eval->pts += nb_samples;

     return ff_filter_frame(outlink, samplesref);

 }
 

 #if CONFIG_AEVALSRC_FILTER

 static const AVFilterPad aevalsrc_outputs[] = {
     {
         .name          = "default",
         .type          = AVMEDIA_TYPE_AUDIO,
         .config_props  = config_props,
         .request_frame = request_frame,
     },
     { NULL }
 };
 

 AVFilter ff_asrc_aevalsrc = {

     .name          = "aevalsrc",
     .description   = NULL_IF_CONFIG_SMALL("Generate an audio signal generated by an expression."),

     .query_formats = query_formats,

     .init          = init,
     .uninit        = uninit,
     .priv_size     = sizeof(EvalContext),
     .inputs        = NULL,
     .outputs       = aevalsrc_outputs,
     .priv_class    = &aevalsrc_class,

 };

 
 #endif /* CONFIG_AEVALSRC_FILTER */
 
 #define OFFSET(x) offsetof(EvalContext, x)
 #define FLAGS AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
 
 static const AVOption aeval_options[]= {
     { "exprs", "set the '|'-separated list of channels expressions", OFFSET(exprs), AV_OPT_TYPE_STRING, {.str = NULL}, .flags = FLAGS },
     { "channel_layout", "set channel layout", OFFSET(chlayout_str), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, FLAGS },
     { "c",              "set channel layout", OFFSET(chlayout_str), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, FLAGS },
     { NULL }
 };
 
 AVFILTER_DEFINE_CLASS(aeval);
 
 static int aeval_query_formats(AVFilterContext *ctx)
 {
     AVFilterFormats *formats = NULL;
     AVFilterChannelLayouts *layouts;
     AVFilterLink *inlink  = ctx->inputs[0];
     AVFilterLink *outlink  = ctx->outputs[0];
     EvalContext *eval = ctx->priv;
     static const enum AVSampleFormat sample_fmts[] = {
         AV_SAMPLE_FMT_DBLP, AV_SAMPLE_FMT_NONE
     };

     int ret;

 
     // inlink supports any channel layout
     layouts = ff_all_channel_counts();

     if ((ret = ff_channel_layouts_ref(layouts, &inlink->out_channel_layouts)) < 0)
         return ret;

 
     if (eval->same_chlayout) {
         layouts = ff_all_channel_counts();

         if ((ret = ff_set_common_channel_layouts(ctx, layouts)) < 0)
             return ret;

     } else {
         // outlink supports only requested output channel layout
         layouts = NULL;

         if ((ret = ff_add_channel_layout(&layouts,

                               eval->out_channel_layout ? eval->out_channel_layout :

                               FF_COUNT2LAYOUT(eval->nb_channels))) < 0)
             return ret;
         if ((ret = ff_channel_layouts_ref(layouts, &outlink->in_channel_layouts)) < 0)
             return ret;

     }
 
     formats = ff_make_format_list(sample_fmts);

     if ((ret = ff_set_common_formats(ctx, formats)) < 0)
         return ret;

 
     formats = ff_all_samplerates();

     return ff_set_common_samplerates(ctx, formats);

 }
 
 static int aeval_config_output(AVFilterLink *outlink)
 {
     AVFilterContext *ctx = outlink->src;
     EvalContext *eval = ctx->priv;
     AVFilterLink *inlink = ctx->inputs[0];
     int ret;
 
     if (eval->same_chlayout) {
         eval->chlayout = inlink->channel_layout;
 
         if ((ret = parse_channel_expressions(ctx, inlink->channels)) < 0)
             return ret;
     }
 
     eval->n = 0;
     eval->nb_in_channels = eval->var_values[VAR_NB_IN_CHANNELS] = inlink->channels;
     eval->var_values[VAR_NB_OUT_CHANNELS] = outlink->channels;
     eval->var_values[VAR_S] = inlink->sample_rate;
     eval->var_values[VAR_T] = NAN;
 
     eval->channel_values = av_realloc_f(eval->channel_values,
                                         inlink->channels, sizeof(*eval->channel_values));
     if (!eval->channel_values)
         return AVERROR(ENOMEM);
 
     return 0;
 }
 
 #define TS2T(ts, tb) ((ts) == AV_NOPTS_VALUE ? NAN : (double)(ts)*av_q2d(tb))
 
 static int filter_frame(AVFilterLink *inlink, AVFrame *in)
 {
     EvalContext *eval     = inlink->dst->priv;
     AVFilterLink *outlink = inlink->dst->outputs[0];
     int nb_samples        = in->nb_samples;
     AVFrame *out;
     double t0;
     int i, j;
 
     out = ff_get_audio_buffer(outlink, nb_samples);

     if (!out) {
         av_frame_free(&in);

         return AVERROR(ENOMEM);

     }

     av_frame_copy_props(out, in);
 
     t0 = TS2T(in->pts, inlink->time_base);
 
     /* evaluate expression for each single sample and for each channel */
     for (i = 0; i < nb_samples; i++, eval->n++) {
         eval->var_values[VAR_N] = eval->n;
         eval->var_values[VAR_T] = t0 + i * (double)1/inlink->sample_rate;
 
         for (j = 0; j < inlink->channels; j++)
             eval->channel_values[j] = *((double *) in->extended_data[j] + i);
 
         for (j = 0; j < outlink->channels; j++) {
             eval->var_values[VAR_CH] = j;
             *((double *) out->extended_data[j] + i) =
                 av_expr_eval(eval->expr[j], eval->var_values, eval);
         }
     }
 
     av_frame_free(&in);
     return ff_filter_frame(outlink, out);
 }
 
 #if CONFIG_AEVAL_FILTER
 
 static const AVFilterPad aeval_inputs[] = {
     {
         .name           = "default",
         .type           = AVMEDIA_TYPE_AUDIO,
         .filter_frame   = filter_frame,
     },
     { NULL }
 };
 
 static const AVFilterPad aeval_outputs[] = {
     {
         .name          = "default",
         .type          = AVMEDIA_TYPE_AUDIO,
         .config_props  = aeval_config_output,
     },
     { NULL }
 };
 
 AVFilter ff_af_aeval = {
     .name          = "aeval",
     .description   = NULL_IF_CONFIG_SMALL("Filter audio signal according to a specified expression."),
     .query_formats = aeval_query_formats,
     .init          = init,
     .uninit        = uninit,
     .priv_size     = sizeof(EvalContext),
     .inputs        = aeval_inputs,
     .outputs       = aeval_outputs,
     .priv_class    = &aeval_class,
 };
 
 #endif /* CONFIG_AEVAL_FILTER */