/*
  * 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
  */
 
 #include "libavutil/audio_fifo.h"
 #include "libavutil/avassert.h"
 #include "libavutil/fifo.h"
 #include "libavutil/internal.h"
 #include "libavutil/opt.h"
 #include "avfilter.h"
 #include "audio.h"

 #include "filters.h"

 #include "formats.h"
 #include "internal.h"
 #include "video.h"
 
 typedef struct LoopContext {
     const AVClass *class;
 
     AVAudioFifo *fifo;
     AVAudioFifo *left;
     AVFrame **frames;
     int nb_frames;
     int current_frame;
     int64_t start_pts;
     int64_t duration;
     int64_t current_sample;
     int64_t nb_samples;
     int64_t ignored_samples;
 
     int loop;

     int eof;

     int64_t size;
     int64_t start;
     int64_t pts;
 } LoopContext;
 
 #define AFLAGS AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
 #define VFLAGS AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
 #define OFFSET(x) offsetof(LoopContext, x)
 

 static void check_size(AVFilterContext *ctx)
 {
     LoopContext *s = ctx->priv;
 
     if (!s->size)
         av_log(ctx, AV_LOG_WARNING, "Number of %s to loop is not set!\n",
                ctx->input_pads[0].type == AVMEDIA_TYPE_VIDEO ? "frames" : "samples");
 }
 

 #if CONFIG_ALOOP_FILTER
 
 static int aconfig_input(AVFilterLink *inlink)
 {
     AVFilterContext *ctx = inlink->dst;
     LoopContext *s  = ctx->priv;
 
     s->fifo = av_audio_fifo_alloc(inlink->format, inlink->channels, 8192);
     s->left = av_audio_fifo_alloc(inlink->format, inlink->channels, 8192);
     if (!s->fifo || !s->left)
         return AVERROR(ENOMEM);
 

     check_size(ctx);
 

     return 0;
 }
 
 static av_cold void auninit(AVFilterContext *ctx)
 {
     LoopContext *s = ctx->priv;
 
     av_audio_fifo_free(s->fifo);
     av_audio_fifo_free(s->left);
 }
 
 static int push_samples(AVFilterContext *ctx, int nb_samples)
 {
     AVFilterLink *outlink = ctx->outputs[0];
     LoopContext *s = ctx->priv;
     AVFrame *out;
     int ret, i = 0;
 
     while (s->loop != 0 && i < nb_samples) {
         out = ff_get_audio_buffer(outlink, FFMIN(nb_samples, s->nb_samples - s->current_sample));
         if (!out)
             return AVERROR(ENOMEM);
         ret = av_audio_fifo_peek_at(s->fifo, (void **)out->extended_data, out->nb_samples, s->current_sample);

         if (ret < 0) {
             av_frame_free(&out);

             return ret;

         }

         out->pts = s->pts;
         out->nb_samples = ret;

         s->pts += av_rescale_q(out->nb_samples, (AVRational){1, outlink->sample_rate}, outlink->time_base);

         i += out->nb_samples;
         s->current_sample += out->nb_samples;
 
         ret = ff_filter_frame(outlink, out);
         if (ret < 0)
             return ret;
 
         if (s->current_sample >= s->nb_samples) {

             s->duration = s->pts;

             s->current_sample = 0;
 
             if (s->loop > 0)
                 s->loop--;
         }
     }
 
     return ret;
 }
 
 static int afilter_frame(AVFilterLink *inlink, AVFrame *frame)
 {
     AVFilterContext *ctx = inlink->dst;
     AVFilterLink *outlink = ctx->outputs[0];
     LoopContext *s = ctx->priv;
     int ret = 0;
 
     if (s->ignored_samples + frame->nb_samples > s->start && s->size > 0 && s->loop != 0) {
         if (s->nb_samples < s->size) {
             int written = FFMIN(frame->nb_samples, s->size - s->nb_samples);
             int drain = 0;
 
             ret = av_audio_fifo_write(s->fifo, (void **)frame->extended_data, written);
             if (ret < 0)
                 return ret;
             if (!s->nb_samples) {
                 drain = FFMAX(0, s->start - s->ignored_samples);
                 s->pts = frame->pts;
                 av_audio_fifo_drain(s->fifo, drain);

                 s->pts += av_rescale_q(s->start - s->ignored_samples, (AVRational){1, outlink->sample_rate}, outlink->time_base);

             }
             s->nb_samples += ret - drain;
             drain = frame->nb_samples - written;
             if (s->nb_samples == s->size && drain > 0) {
                 int ret2;
 
                 ret2 = av_audio_fifo_write(s->left, (void **)frame->extended_data, frame->nb_samples);
                 if (ret2 < 0)
                    return ret2;
                 av_audio_fifo_drain(s->left, drain);
             }
             frame->nb_samples = ret;

             s->pts += av_rescale_q(ret, (AVRational){1, outlink->sample_rate}, outlink->time_base);

             ret = ff_filter_frame(outlink, frame);
         } else {
             int nb_samples = frame->nb_samples;
 
             av_frame_free(&frame);
             ret = push_samples(ctx, nb_samples);
         }
     } else {
         s->ignored_samples += frame->nb_samples;
         frame->pts = s->pts;

         s->pts += av_rescale_q(frame->nb_samples, (AVRational){1, outlink->sample_rate}, outlink->time_base);

         ret = ff_filter_frame(outlink, frame);
     }
 
     return ret;
 }
 
 static int arequest_frame(AVFilterLink *outlink)
 {
     AVFilterContext *ctx = outlink->src;
     LoopContext *s = ctx->priv;
     int ret = 0;
 
     if ((!s->size) ||
         (s->nb_samples < s->size) ||
         (s->nb_samples >= s->size && s->loop == 0)) {
         int nb_samples = av_audio_fifo_size(s->left);
 
         if (s->loop == 0 && nb_samples > 0) {
             AVFrame *out;
 
             out = ff_get_audio_buffer(outlink, nb_samples);
             if (!out)
                 return AVERROR(ENOMEM);
             av_audio_fifo_read(s->left, (void **)out->extended_data, nb_samples);
             out->pts = s->pts;

             s->pts += av_rescale_q(nb_samples, (AVRational){1, outlink->sample_rate}, outlink->time_base);

             ret = ff_filter_frame(outlink, out);
             if (ret < 0)
                 return ret;
         }
         ret = ff_request_frame(ctx->inputs[0]);
     } else {
         ret = push_samples(ctx, 1024);
     }
 

     if (s->eof && s->nb_samples > 0 && s->loop != 0) {
         ret = push_samples(ctx, 1024);

     }
 
     return ret;
 }
 

 static int aactivate(AVFilterContext *ctx)
 {
     AVFilterLink *inlink = ctx->inputs[0];
     AVFilterLink *outlink = ctx->outputs[0];
     LoopContext *s = ctx->priv;
     AVFrame *frame = NULL;
     int ret, status;
     int64_t pts;
 
     FF_FILTER_FORWARD_STATUS_BACK(outlink, inlink);
 
     if (!s->eof && (s->nb_samples < s->size || !s->loop || !s->size)) {
         ret = ff_inlink_consume_frame(inlink, &frame);
         if (ret < 0)
             return ret;
         if (ret > 0)
             return afilter_frame(inlink, frame);
     }
 
     if (!s->eof && ff_inlink_acknowledge_status(inlink, &status, &pts)) {
         if (status == AVERROR_EOF) {
             s->size = s->nb_samples;
             s->eof = 1;
         }
     }
 
     if (s->eof && (!s->loop || !s->size)) {
         ff_outlink_set_status(outlink, AVERROR_EOF, s->duration);
         return 0;
     }
 
     if (!s->eof && (!s->size ||
         (s->nb_samples < s->size) ||
         (s->nb_samples >= s->size && s->loop == 0))) {
         FF_FILTER_FORWARD_WANTED(outlink, inlink);
     } else if (s->loop && s->nb_samples == s->size) {
         return arequest_frame(outlink);
     }
 
     return FFERROR_NOT_READY;
 }
 

 static const AVOption aloop_options[] = {
     { "loop",  "number of loops",               OFFSET(loop),  AV_OPT_TYPE_INT,   {.i64 = 0 }, -1, INT_MAX,   AFLAGS },
     { "size",  "max number of samples to loop", OFFSET(size),  AV_OPT_TYPE_INT64, {.i64 = 0 },  0, INT32_MAX, AFLAGS },
     { "start", "set the loop start sample",     OFFSET(start), AV_OPT_TYPE_INT64, {.i64 = 0 },  0, INT64_MAX, AFLAGS },
     { NULL }
 };
 
 AVFILTER_DEFINE_CLASS(aloop);
 
 static const AVFilterPad ainputs[] = {
     {
         .name         = "default",
         .type         = AVMEDIA_TYPE_AUDIO,
         .config_props = aconfig_input,
     },
     { NULL }
 };
 
 static const AVFilterPad aoutputs[] = {
     {
         .name          = "default",
         .type          = AVMEDIA_TYPE_AUDIO,
     },
     { NULL }
 };
 
 AVFilter ff_af_aloop = {
     .name          = "aloop",
     .description   = NULL_IF_CONFIG_SMALL("Loop audio samples."),
     .priv_size     = sizeof(LoopContext),
     .priv_class    = &aloop_class,

     .activate      = aactivate,

     .uninit        = auninit,
     .inputs        = ainputs,
     .outputs       = aoutputs,
 };
 #endif /* CONFIG_ALOOP_FILTER */
 
 #if CONFIG_LOOP_FILTER
 
 static av_cold int init(AVFilterContext *ctx)
 {
     LoopContext *s = ctx->priv;
 
     s->frames = av_calloc(s->size, sizeof(*s->frames));
     if (!s->frames)
         return AVERROR(ENOMEM);
 

     check_size(ctx);
 

     return 0;
 }
 
 static av_cold void uninit(AVFilterContext *ctx)
 {
     LoopContext *s = ctx->priv;
     int i;
 
     for (i = 0; i < s->nb_frames; i++)
         av_frame_free(&s->frames[i]);
 
     av_freep(&s->frames);
     s->nb_frames = 0;
 }
 
 static int push_frame(AVFilterContext *ctx)
 {
     AVFilterLink *outlink = ctx->outputs[0];
     LoopContext *s = ctx->priv;

     int64_t pts, duration;

     int ret;
 
     AVFrame *out = av_frame_clone(s->frames[s->current_frame]);
 
     if (!out)
         return AVERROR(ENOMEM);
     out->pts += s->duration - s->start_pts;

     if (out->pkt_duration)
         duration = out->pkt_duration;
     else
         duration = av_rescale_q(1, av_inv_q(outlink->frame_rate), outlink->time_base);
     pts = out->pts + duration;

     ret = ff_filter_frame(outlink, out);
     s->current_frame++;
 
     if (s->current_frame >= s->nb_frames) {
         s->duration = pts;
         s->current_frame = 0;
 
         if (s->loop > 0)
             s->loop--;
     }
 
     return ret;
 }
 
 static int filter_frame(AVFilterLink *inlink, AVFrame *frame)
 {
     AVFilterContext *ctx = inlink->dst;
     AVFilterLink *outlink = ctx->outputs[0];
     LoopContext *s = ctx->priv;

     int64_t duration;

     int ret = 0;
 

     if (inlink->frame_count_out >= s->start && s->size > 0 && s->loop != 0) {

         if (s->nb_frames < s->size) {
             if (!s->nb_frames)
                 s->start_pts = frame->pts;
             s->frames[s->nb_frames] = av_frame_clone(frame);
             if (!s->frames[s->nb_frames]) {
                 av_frame_free(&frame);
                 return AVERROR(ENOMEM);
             }
             s->nb_frames++;

             if (frame->pkt_duration)
                 duration = frame->pkt_duration;
             else
                 duration = av_rescale_q(1, av_inv_q(outlink->frame_rate), outlink->time_base);
             s->duration = frame->pts + duration;

             ret = ff_filter_frame(outlink, frame);
         } else {
             av_frame_free(&frame);
             ret = push_frame(ctx);
         }
     } else {
         frame->pts += s->duration;
         ret = ff_filter_frame(outlink, frame);
     }
 
     return ret;
 }
 

 static int activate(AVFilterContext *ctx)

 {

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

     LoopContext *s = ctx->priv;

     AVFrame *frame = NULL;
     int ret, status;
     int64_t pts;

     FF_FILTER_FORWARD_STATUS_BACK(outlink, inlink);
 

     if (!s->eof && (s->nb_frames < s->size || !s->loop || !s->size)) {

         ret = ff_inlink_consume_frame(inlink, &frame);
         if (ret < 0)
             return ret;
         if (ret > 0)
             return filter_frame(inlink, frame);

     }
 

     if (!s->eof && ff_inlink_acknowledge_status(inlink, &status, &pts)) {

         if (status == AVERROR_EOF) {
             s->size = s->nb_frames;

             s->eof = 1;

         }

     }
 

     if (s->eof && (!s->loop || !s->size)) {

         ff_outlink_set_status(outlink, AVERROR_EOF, s->duration);
         return 0;
     }
 
     if (!s->eof && (!s->size ||
         (s->nb_frames < s->size) ||
         (s->nb_frames >= s->size && s->loop == 0))) {
         FF_FILTER_FORWARD_WANTED(outlink, inlink);
     } else if (s->loop && s->nb_frames == s->size) {
         return push_frame(ctx);
     }
 
     return FFERROR_NOT_READY;

 }
 
 static const AVOption loop_options[] = {
     { "loop",  "number of loops",              OFFSET(loop),  AV_OPT_TYPE_INT,   {.i64 = 0 }, -1, INT_MAX,   VFLAGS },
     { "size",  "max number of frames to loop", OFFSET(size),  AV_OPT_TYPE_INT64, {.i64 = 0 },  0, INT16_MAX, VFLAGS },
     { "start", "set the loop start frame",     OFFSET(start), AV_OPT_TYPE_INT64, {.i64 = 0 },  0, INT64_MAX, VFLAGS },
     { NULL }
 };
 
 AVFILTER_DEFINE_CLASS(loop);
 
 static const AVFilterPad inputs[] = {
     {

         .name = "default",
         .type = AVMEDIA_TYPE_VIDEO,

     },
     { NULL }
 };
 
 static const AVFilterPad outputs[] = {
     {

         .name = "default",
         .type = AVMEDIA_TYPE_VIDEO,

     },
     { NULL }
 };
 
 AVFilter ff_vf_loop = {
     .name        = "loop",
     .description = NULL_IF_CONFIG_SMALL("Loop video frames."),
     .priv_size   = sizeof(LoopContext),
     .priv_class  = &loop_class,
     .init        = init,
     .uninit      = uninit,

     .activate    = activate,

     .inputs      = inputs,
     .outputs     = outputs,
 };
 #endif /* CONFIG_LOOP_FILTER */