/*
  * Apple HTTP Live Streaming segmenter
  * Copyright (c) 2012, Luca Barbato
  *

  * 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>

 #include <stdint.h>

 
 #include "libavutil/mathematics.h"
 #include "libavutil/parseutils.h"
 #include "libavutil/avstring.h"
 #include "libavutil/opt.h"
 #include "libavutil/log.h"
 
 #include "avformat.h"
 #include "internal.h"
 
 typedef struct ListEntry {
     char  name[1024];
     int   duration;
     struct ListEntry *next;
 } ListEntry;
 
 typedef struct HLSContext {
     const AVClass *class;  // Class for private options.

     unsigned number;

     int64_t sequence;

     AVOutputFormat *oformat;
     AVFormatContext *avf;
     float time;            // Set by a private option.
     int  size;             // Set by a private option.
     int  wrap;             // Set by a private option.
     int64_t recording_time;
     int has_video;
     int64_t start_pts;
     int64_t end_pts;

     int64_t duration;      // last segment duration computed so far, in seconds

     int nb_entries;

     ListEntry *list;
     ListEntry *end_list;
     char *basename;
     AVIOContext *pb;
 } HLSContext;
 
 static int hls_mux_init(AVFormatContext *s)
 {
     HLSContext *hls = s->priv_data;
     AVFormatContext *oc;
     int i;
 
     hls->avf = oc = avformat_alloc_context();
     if (!oc)
         return AVERROR(ENOMEM);
 
     oc->oformat            = hls->oformat;
     oc->interrupt_callback = s->interrupt_callback;

     av_dict_copy(&oc->metadata, s->metadata, 0);

 
     for (i = 0; i < s->nb_streams; i++) {
         AVStream *st;
         if (!(st = avformat_new_stream(oc, NULL)))
             return AVERROR(ENOMEM);
         avcodec_copy_context(st->codec, s->streams[i]->codec);
         st->sample_aspect_ratio = s->streams[i]->sample_aspect_ratio;
     }
 
     return 0;
 }
 
 static int append_entry(HLSContext *hls, uint64_t duration)
 {
     ListEntry *en = av_malloc(sizeof(*en));
 
     if (!en)
         return AVERROR(ENOMEM);
 

     av_strlcpy(en->name, av_basename(hls->avf->filename), sizeof(en->name));

 
     en->duration = duration;
     en->next     = NULL;
 
     if (!hls->list)
         hls->list = en;
     else
         hls->end_list->next = en;
 
     hls->end_list = en;
 

     if (hls->nb_entries >= hls->size) {

         en = hls->list;
         hls->list = en->next;
         av_free(en);

     } else
         hls->nb_entries++;

     hls->sequence++;
 

     return 0;
 }
 
 static void free_entries(HLSContext *hls)
 {
     ListEntry *p = hls->list, *en;
 
     while(p) {
         en = p;
         p = p->next;
         av_free(en);
     }
 }
 
 static int hls_window(AVFormatContext *s, int last)
 {
     HLSContext *hls = s->priv_data;
     ListEntry *en;

     int target_duration = 0;

     int ret = 0;
 
     if ((ret = avio_open2(&hls->pb, s->filename, AVIO_FLAG_WRITE,
                           &s->interrupt_callback, NULL)) < 0)
         goto fail;
 

     for (en = hls->list; en; en = en->next) {
         if (target_duration < en->duration)
             target_duration = en->duration;
     }
 

     avio_printf(hls->pb, "#EXTM3U\n");
     avio_printf(hls->pb, "#EXT-X-VERSION:3\n");

     avio_printf(hls->pb, "#EXT-X-TARGETDURATION:%d\n", target_duration);

     avio_printf(hls->pb, "#EXT-X-MEDIA-SEQUENCE:%"PRId64"\n",
                 FFMAX(0, hls->sequence - hls->size));

 
     for (en = hls->list; en; en = en->next) {
         avio_printf(hls->pb, "#EXTINF:%d,\n", en->duration);
         avio_printf(hls->pb, "%s\n", en->name);
     }
 
     if (last)
         avio_printf(hls->pb, "#EXT-X-ENDLIST\n");
 
 fail:
     avio_closep(&hls->pb);
     return ret;
 }
 
 static int hls_start(AVFormatContext *s)
 {
     HLSContext *c = s->priv_data;
     AVFormatContext *oc = c->avf;
     int err = 0;
 
     if (av_get_frame_filename(oc->filename, sizeof(oc->filename),

                               c->basename, c->wrap ? c->number % c->wrap : c->number) < 0) {

         av_log(oc, AV_LOG_ERROR, "Invalid segment filename template '%s'\n", c->basename);

         return AVERROR(EINVAL);

     }

     c->number++;

 
     if ((err = avio_open2(&oc->pb, oc->filename, AVIO_FLAG_WRITE,
                           &s->interrupt_callback, NULL)) < 0)
         return err;
 
     if (oc->oformat->priv_class && oc->priv_data)
         av_opt_set(oc->priv_data, "mpegts_flags", "resend_headers", 0);
 
     return 0;
 }
 
 static int hls_write_header(AVFormatContext *s)
 {
     HLSContext *hls = s->priv_data;
     int ret, i;
     char *p;
     const char *pattern = "%d.ts";

     int basename_size = strlen(s->filename) + strlen(pattern) + 1;

 
     hls->number      = 0;
 

     hls->recording_time = hls->time * AV_TIME_BASE;

     hls->start_pts      = AV_NOPTS_VALUE;
 
     for (i = 0; i < s->nb_streams; i++)
         hls->has_video +=
             s->streams[i]->codec->codec_type == AVMEDIA_TYPE_VIDEO;
 
     if (hls->has_video > 1)
         av_log(s, AV_LOG_WARNING,
                "More than a single video stream present, "
                "expect issues decoding it.\n");
 
     hls->oformat = av_guess_format("mpegts", NULL, NULL);
 
     if (!hls->oformat) {
         ret = AVERROR_MUXER_NOT_FOUND;
         goto fail;
     }
 
     hls->basename = av_malloc(basename_size);
 
     if (!hls->basename) {
         ret = AVERROR(ENOMEM);
         goto fail;
     }
 
     strcpy(hls->basename, s->filename);
 
     p = strrchr(hls->basename, '.');
 
     if (p)
         *p = '\0';
 

     av_strlcat(hls->basename, pattern, basename_size);

 
     if ((ret = hls_mux_init(s)) < 0)
         goto fail;
 
     if ((ret = hls_start(s)) < 0)
         goto fail;
 
     if ((ret = avformat_write_header(hls->avf, NULL)) < 0)
         return ret;
 
 
 fail:
     if (ret) {
         av_free(hls->basename);
         if (hls->avf)
             avformat_free_context(hls->avf);
     }
     return ret;
 }
 
 static int hls_write_packet(AVFormatContext *s, AVPacket *pkt)
 {
     HLSContext *hls = s->priv_data;
     AVFormatContext *oc = hls->avf;
     AVStream *st = s->streams[pkt->stream_index];
     int64_t end_pts = hls->recording_time * hls->number;

     int is_ref_pkt = 1;

     int ret, can_split = 1;

 
     if (hls->start_pts == AV_NOPTS_VALUE) {
         hls->start_pts = pkt->pts;
         hls->end_pts   = pkt->pts;
     }
 

     if (hls->has_video) {
         can_split = st->codec->codec_type == AVMEDIA_TYPE_VIDEO &&
                     pkt->flags & AV_PKT_FLAG_KEY;

         is_ref_pkt = st->codec->codec_type == AVMEDIA_TYPE_VIDEO;

     }

     if (pkt->pts == AV_NOPTS_VALUE)
         is_ref_pkt = can_split = 0;

     if (is_ref_pkt)
         hls->duration = av_rescale(pkt->pts - hls->end_pts,
                                    st->time_base.num, st->time_base.den);

     if (can_split && av_compare_ts(pkt->pts - hls->start_pts, st->time_base,
                                    end_pts, AV_TIME_BASE_Q) >= 0) {

         ret = append_entry(hls, hls->duration);

         if (ret)
             return ret;
 

         hls->end_pts = pkt->pts;

         hls->duration = 0;

 
         av_write_frame(oc, NULL); /* Flush any buffered data */
         avio_close(oc->pb);
 
         ret = hls_start(s);
 
         if (ret)
             return ret;
 
         oc = hls->avf;
 
         if ((ret = hls_window(s, 0)) < 0)
             return ret;
     }
 
     ret = ff_write_chained(oc, pkt->stream_index, pkt, s);
 
     return ret;
 }
 
 static int hls_write_trailer(struct AVFormatContext *s)
 {
     HLSContext *hls = s->priv_data;
     AVFormatContext *oc = hls->avf;
 
     av_write_trailer(oc);
     avio_closep(&oc->pb);
     av_free(hls->basename);

     append_entry(hls, hls->duration);

     avformat_free_context(oc);
     hls->avf = NULL;

     hls_window(s, 1);
 
     free_entries(hls);
     avio_close(hls->pb);
     return 0;
 }
 
 #define OFFSET(x) offsetof(HLSContext, x)
 #define E AV_OPT_FLAG_ENCODING_PARAM
 static const AVOption options[] = {

     {"start_number",  "set first number in the sequence",        OFFSET(sequence),AV_OPT_TYPE_INT64,  {.i64 = 0},     0, INT64_MAX, E},
     {"hls_time",      "set segment length in seconds",           OFFSET(time),    AV_OPT_TYPE_FLOAT,  {.dbl = 2},     0, FLT_MAX, E},
     {"hls_list_size", "set maximum number of playlist entries",  OFFSET(size),    AV_OPT_TYPE_INT,    {.i64 = 5},     0, INT_MAX, E},
     {"hls_wrap",      "set number after which the index wraps",  OFFSET(wrap),    AV_OPT_TYPE_INT,    {.i64 = 0},     0, INT_MAX, E},

     { NULL },
 };
 
 static const AVClass hls_class = {
     .class_name = "hls muxer",
     .item_name  = av_default_item_name,
     .option     = options,
     .version    = LIBAVUTIL_VERSION_INT,
 };
 
 
 AVOutputFormat ff_hls_muxer = {
     .name           = "hls",

     .long_name      = NULL_IF_CONFIG_SMALL("Apple HTTP Live Streaming"),

     .extensions     = "m3u8",
     .priv_data_size = sizeof(HLSContext),
     .audio_codec    = AV_CODEC_ID_MP2,
     .video_codec    = AV_CODEC_ID_MPEG2VIDEO,
     .flags          = AVFMT_NOFILE | AVFMT_ALLOW_FLUSH,
     .write_header   = hls_write_header,
     .write_packet   = hls_write_packet,
     .write_trailer  = hls_write_trailer,
     .priv_class     = &hls_class,
 };