/*
  * Live HDS fragmenter
  * Copyright (c) 2013 Martin Storsjo
  *

  * 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 "config.h"
 #include <float.h>
 #if HAVE_UNISTD_H
 #include <unistd.h>
 #endif
 
 #include "avformat.h"
 #include "internal.h"
 #include "os_support.h"
 
 #include "libavutil/avstring.h"
 #include "libavutil/base64.h"
 #include "libavutil/intreadwrite.h"
 #include "libavutil/mathematics.h"
 #include "libavutil/opt.h"
 
 typedef struct Fragment {
     char file[1024];
     int64_t start_time, duration;
     int n;
 } Fragment;
 
 typedef struct OutputStream {
     int bitrate;
     int first_stream;
     AVFormatContext *ctx;
     int ctx_inited;
     uint8_t iobuf[32768];
     char temp_filename[1024];
     int64_t frag_start_ts, last_ts;
     AVIOContext *out;
     int packets_written;
     int nb_fragments, fragments_size, fragment_index;
     Fragment **fragments;
 
     int has_audio, has_video;
 
     uint8_t *metadata;
     int metadata_size;
 
     uint8_t *extra_packets[2];
     int extra_packet_sizes[2];
     int nb_extra_packets;
 } OutputStream;
 
 typedef struct HDSContext {
     const AVClass *class;  /* Class for private options. */
     int window_size;
     int extra_window_size;
     int min_frag_duration;
     int remove_at_exit;
 
     OutputStream *streams;
     int nb_streams;
 } HDSContext;
 
 static int parse_header(OutputStream *os, const uint8_t *buf, int buf_size)
 {
     if (buf_size < 13)
         return AVERROR_INVALIDDATA;
     if (memcmp(buf, "FLV", 3))
         return AVERROR_INVALIDDATA;
     buf      += 13;
     buf_size -= 13;
     while (buf_size >= 11 + 4) {
         int type = buf[0];
         int size = AV_RB24(&buf[1]) + 11 + 4;
         if (size > buf_size)
             return AVERROR_INVALIDDATA;
         if (type == 8 || type == 9) {

             if (os->nb_extra_packets >= FF_ARRAY_ELEMS(os->extra_packets))

                 return AVERROR_INVALIDDATA;
             os->extra_packet_sizes[os->nb_extra_packets] = size;
             os->extra_packets[os->nb_extra_packets] = av_malloc(size);
             if (!os->extra_packets[os->nb_extra_packets])
                 return AVERROR(ENOMEM);
             memcpy(os->extra_packets[os->nb_extra_packets], buf, size);
             os->nb_extra_packets++;
         } else if (type == 0x12) {
             if (os->metadata)
                 return AVERROR_INVALIDDATA;
             os->metadata_size = size - 11 - 4;
             os->metadata      = av_malloc(os->metadata_size);
             if (!os->metadata)
                 return AVERROR(ENOMEM);
             memcpy(os->metadata, buf + 11, os->metadata_size);
         }
         buf      += size;
         buf_size -= size;
     }
     if (!os->metadata)
         return AVERROR_INVALIDDATA;
     return 0;
 }
 
 static int hds_write(void *opaque, uint8_t *buf, int buf_size)
 {
     OutputStream *os = opaque;
     if (os->out) {
         avio_write(os->out, buf, buf_size);
     } else {
         if (!os->metadata_size) {
             int ret;
             // Assuming the IO buffer is large enough to fit the
             // FLV header and all metadata and extradata packets
             if ((ret = parse_header(os, buf, buf_size)) < 0)
                 return ret;
         }
     }
     return buf_size;
 }
 
 static void hds_free(AVFormatContext *s)
 {
     HDSContext *c = s->priv_data;
     int i, j;
     if (!c->streams)
         return;
     for (i = 0; i < s->nb_streams; i++) {
         OutputStream *os = &c->streams[i];

         avio_closep(&os->out);

         if (os->ctx && os->ctx_inited)
             av_write_trailer(os->ctx);

         if (os->ctx)

             av_freep(&os->ctx->pb);

         if (os->ctx)
             avformat_free_context(os->ctx);

         av_freep(&os->metadata);

         for (j = 0; j < os->nb_extra_packets; j++)

             av_freep(&os->extra_packets[j]);

         for (j = 0; j < os->nb_fragments; j++)

             av_freep(&os->fragments[j]);
         av_freep(&os->fragments);

     }
     av_freep(&c->streams);
 }
 
 static int write_manifest(AVFormatContext *s, int final)
 {
     HDSContext *c = s->priv_data;
     AVIOContext *out;
     char filename[1024], temp_filename[1024];
     int ret, i;

     double duration = 0;

 
     if (c->nb_streams > 0)
         duration = c->streams[0].last_ts * av_q2d(s->streams[0]->time_base);
 
     snprintf(filename, sizeof(filename), "%s/index.f4m", s->filename);
     snprintf(temp_filename, sizeof(temp_filename), "%s/index.f4m.tmp", s->filename);

     ret = avio_open2(&out, temp_filename, AVIO_FLAG_WRITE,

                      &s->interrupt_callback, NULL);
     if (ret < 0) {

         av_log(s, AV_LOG_ERROR, "Unable to open %s for writing\n", temp_filename);

         return ret;
     }
     avio_printf(out, "<?xml version=\"1.0\" encoding=\"utf-8\"?>\n");
     avio_printf(out, "<manifest xmlns=\"http://ns.adobe.com/f4m/1.0\">\n");
     avio_printf(out, "\t<id>%s</id>\n", av_basename(s->filename));
     avio_printf(out, "\t<streamType>%s</streamType>\n",
                      final ? "recorded" : "live");
     avio_printf(out, "\t<deliveryType>streaming</deliveryType>\n");
     if (final)
         avio_printf(out, "\t<duration>%f</duration>\n", duration);
     for (i = 0; i < c->nb_streams; i++) {
         OutputStream *os = &c->streams[i];
         int b64_size = AV_BASE64_SIZE(os->metadata_size);
         char *base64 = av_malloc(b64_size);
         if (!base64) {
             avio_close(out);
             return AVERROR(ENOMEM);
         }
         av_base64_encode(base64, b64_size, os->metadata, os->metadata_size);
 
         avio_printf(out, "\t<bootstrapInfo profile=\"named\" url=\"stream%d.abst\" id=\"bootstrap%d\" />\n", i, i);
         avio_printf(out, "\t<media bitrate=\"%d\" url=\"stream%d\" bootstrapInfoId=\"bootstrap%d\">\n", os->bitrate/1000, i, i);
         avio_printf(out, "\t\t<metadata>%s</metadata>\n", base64);
         avio_printf(out, "\t</media>\n");
         av_free(base64);
     }
     avio_printf(out, "</manifest>\n");
     avio_flush(out);
     avio_close(out);

     return ff_rename(temp_filename, filename, s);

 }
 
 static void update_size(AVIOContext *out, int64_t pos)
 {
     int64_t end = avio_tell(out);
     avio_seek(out, pos, SEEK_SET);
     avio_wb32(out, end - pos);
     avio_seek(out, end, SEEK_SET);
 }
 
 /* Note, the .abst files need to be served with the "binary/octet"
  * mime type, otherwise at least the OSMF player can easily fail
  * with "stream not found" when polling for the next fragment. */
 static int write_abst(AVFormatContext *s, OutputStream *os, int final)
 {
     HDSContext *c = s->priv_data;
     AVIOContext *out;
     char filename[1024], temp_filename[1024];
     int i, ret;
     int64_t asrt_pos, afrt_pos;
     int start = 0, fragments;
     int index = s->streams[os->first_stream]->id;
     int64_t cur_media_time = 0;
     if (c->window_size)
         start = FFMAX(os->nb_fragments - c->window_size, 0);
     fragments = os->nb_fragments - start;
     if (final)
         cur_media_time = os->last_ts;
     else if (os->nb_fragments)
         cur_media_time = os->fragments[os->nb_fragments - 1]->start_time;
 
     snprintf(filename, sizeof(filename),
              "%s/stream%d.abst", s->filename, index);
     snprintf(temp_filename, sizeof(temp_filename),
              "%s/stream%d.abst.tmp", s->filename, index);

     ret = avio_open2(&out, temp_filename, AVIO_FLAG_WRITE,

                      &s->interrupt_callback, NULL);
     if (ret < 0) {

         av_log(s, AV_LOG_ERROR, "Unable to open %s for writing\n", temp_filename);

         return ret;
     }
     avio_wb32(out, 0); // abst size
     avio_wl32(out, MKTAG('a','b','s','t'));
     avio_wb32(out, 0); // version + flags
     avio_wb32(out, os->fragment_index - 1); // BootstrapinfoVersion
     avio_w8(out, final ? 0 : 0x20); // profile, live, update
     avio_wb32(out, 1000); // timescale
     avio_wb64(out, cur_media_time);
     avio_wb64(out, 0); // SmpteTimeCodeOffset
     avio_w8(out, 0); // MovieIdentifer (null string)
     avio_w8(out, 0); // ServerEntryCount
     avio_w8(out, 0); // QualityEntryCount
     avio_w8(out, 0); // DrmData (null string)
     avio_w8(out, 0); // MetaData (null string)
     avio_w8(out, 1); // SegmentRunTableCount
     asrt_pos = avio_tell(out);
     avio_wb32(out, 0); // asrt size
     avio_wl32(out, MKTAG('a','s','r','t'));
     avio_wb32(out, 0); // version + flags
     avio_w8(out, 0); // QualityEntryCount
     avio_wb32(out, 1); // SegmentRunEntryCount
     avio_wb32(out, 1); // FirstSegment
     avio_wb32(out, final ? (os->fragment_index - 1) : 0xffffffff); // FragmentsPerSegment
     update_size(out, asrt_pos);
     avio_w8(out, 1); // FragmentRunTableCount
     afrt_pos = avio_tell(out);
     avio_wb32(out, 0); // afrt size
     avio_wl32(out, MKTAG('a','f','r','t'));
     avio_wb32(out, 0); // version + flags
     avio_wb32(out, 1000); // timescale
     avio_w8(out, 0); // QualityEntryCount
     avio_wb32(out, fragments); // FragmentRunEntryCount
     for (i = start; i < os->nb_fragments; i++) {
         avio_wb32(out, os->fragments[i]->n);
         avio_wb64(out, os->fragments[i]->start_time);
         avio_wb32(out, os->fragments[i]->duration);
     }
     update_size(out, afrt_pos);
     update_size(out, 0);
     avio_close(out);

     return ff_rename(temp_filename, filename, s);

 }
 
 static int init_file(AVFormatContext *s, OutputStream *os, int64_t start_ts)
 {
     int ret, i;
     ret = avio_open2(&os->out, os->temp_filename, AVIO_FLAG_WRITE,
                      &s->interrupt_callback, NULL);
     if (ret < 0)
         return ret;
     avio_wb32(os->out, 0);
     avio_wl32(os->out, MKTAG('m','d','a','t'));
     for (i = 0; i < os->nb_extra_packets; i++) {
         AV_WB24(os->extra_packets[i] + 4, start_ts);
         os->extra_packets[i][7] = (start_ts >> 24) & 0x7f;
         avio_write(os->out, os->extra_packets[i], os->extra_packet_sizes[i]);
     }
     return 0;
 }
 
 static void close_file(OutputStream *os)
 {
     int64_t pos = avio_tell(os->out);
     avio_seek(os->out, 0, SEEK_SET);
     avio_wb32(os->out, pos);
     avio_flush(os->out);

     avio_closep(&os->out);

 }
 
 static int hds_write_header(AVFormatContext *s)
 {
     HDSContext *c = s->priv_data;
     int ret = 0, i;
     AVOutputFormat *oformat;
 

     if (mkdir(s->filename, 0777) == -1 && errno != EEXIST) {
         ret = AVERROR(errno);

         av_log(s, AV_LOG_ERROR , "Failed to create directory %s\n", s->filename);

         goto fail;

     }

 
     oformat = av_guess_format("flv", NULL, NULL);
     if (!oformat) {
         ret = AVERROR_MUXER_NOT_FOUND;
         goto fail;
     }
 

     c->streams = av_mallocz_array(s->nb_streams, sizeof(*c->streams));

     if (!c->streams) {
         ret = AVERROR(ENOMEM);
         goto fail;
     }
 
     for (i = 0; i < s->nb_streams; i++) {
         OutputStream *os = &c->streams[c->nb_streams];
         AVFormatContext *ctx;
         AVStream *st = s->streams[i];
 
         if (!st->codec->bit_rate) {
             av_log(s, AV_LOG_ERROR, "No bit rate set for stream %d\n", i);
             ret = AVERROR(EINVAL);
             goto fail;
         }
         if (st->codec->codec_type == AVMEDIA_TYPE_VIDEO) {
             if (os->has_video) {
                 c->nb_streams++;
                 os++;
             }
             os->has_video = 1;
         } else if (st->codec->codec_type == AVMEDIA_TYPE_AUDIO) {
             if (os->has_audio) {
                 c->nb_streams++;
                 os++;
             }
             os->has_audio = 1;
         } else {
             av_log(s, AV_LOG_ERROR, "Unsupported stream type in stream %d\n", i);
             ret = AVERROR(EINVAL);
             goto fail;
         }
         os->bitrate += s->streams[i]->codec->bit_rate;
 
         if (!os->ctx) {
             os->first_stream = i;
             ctx = avformat_alloc_context();
             if (!ctx) {
                 ret = AVERROR(ENOMEM);
                 goto fail;
             }
             os->ctx = ctx;
             ctx->oformat = oformat;
             ctx->interrupt_callback = s->interrupt_callback;
 
             ctx->pb = avio_alloc_context(os->iobuf, sizeof(os->iobuf),
                                          AVIO_FLAG_WRITE, os,
                                          NULL, hds_write, NULL);
             if (!ctx->pb) {
                 ret = AVERROR(ENOMEM);
                 goto fail;
             }
         } else {
             ctx = os->ctx;
         }
         s->streams[i]->id = c->nb_streams;
 
         if (!(st = avformat_new_stream(ctx, NULL))) {
             ret = AVERROR(ENOMEM);
             goto fail;
         }
         avcodec_copy_context(st->codec, s->streams[i]->codec);

         st->codec->codec_tag = 0;

         st->sample_aspect_ratio = s->streams[i]->sample_aspect_ratio;

         st->time_base = s->streams[i]->time_base;

     }
     if (c->streams[c->nb_streams].ctx)
         c->nb_streams++;
 
     for (i = 0; i < c->nb_streams; i++) {
         OutputStream *os = &c->streams[i];
         int j;
         if ((ret = avformat_write_header(os->ctx, NULL)) < 0) {
              goto fail;
         }
         os->ctx_inited = 1;
         avio_flush(os->ctx->pb);
         for (j = 0; j < os->ctx->nb_streams; j++)
             s->streams[os->first_stream + j]->time_base = os->ctx->streams[j]->time_base;
 
         snprintf(os->temp_filename, sizeof(os->temp_filename),
                  "%s/stream%d_temp", s->filename, i);

         ret = init_file(s, os, 0);
         if (ret < 0)
             goto fail;

 
         if (!os->has_video && c->min_frag_duration <= 0) {
             av_log(s, AV_LOG_WARNING,
                    "No video stream in output stream %d and no min frag duration set\n", i);
             ret = AVERROR(EINVAL);
         }
         os->fragment_index = 1;
         write_abst(s, os, 0);
     }
     ret = write_manifest(s, 0);
 
 fail:
     if (ret)
         hds_free(s);
     return ret;
 }
 
 static int add_fragment(OutputStream *os, const char *file,
                         int64_t start_time, int64_t duration)
 {
     Fragment *frag;
     if (duration == 0)
         duration = 1;
     if (os->nb_fragments >= os->fragments_size) {
         int ret;
         os->fragments_size = (os->fragments_size + 1) * 2;
         if ((ret = av_reallocp_array(&os->fragments, os->fragments_size,
                                      sizeof(*os->fragments))) < 0) {
             os->fragments_size = 0;
             os->nb_fragments   = 0;
             return ret;
         }
     }
     frag = av_mallocz(sizeof(*frag));
     if (!frag)
         return AVERROR(ENOMEM);
     av_strlcpy(frag->file, file, sizeof(frag->file));
     frag->start_time = start_time;
     frag->duration   = duration;
     frag->n          = os->fragment_index;
     os->fragments[os->nb_fragments++] = frag;
     os->fragment_index++;
     return 0;
 }
 
 static int hds_flush(AVFormatContext *s, OutputStream *os, int final,
                      int64_t end_ts)
 {
     HDSContext *c = s->priv_data;
     int i, ret = 0;
     char target_filename[1024];
     int index = s->streams[os->first_stream]->id;
 
     if (!os->packets_written)
         return 0;
 
     avio_flush(os->ctx->pb);
     os->packets_written = 0;
     close_file(os);
 
     snprintf(target_filename, sizeof(target_filename),
              "%s/stream%dSeg1-Frag%d", s->filename, index, os->fragment_index);

     ret = ff_rename(os->temp_filename, target_filename, s);

     if (ret < 0)
         return ret;

     add_fragment(os, target_filename, os->frag_start_ts, end_ts - os->frag_start_ts);
 
     if (!final) {
         ret = init_file(s, os, end_ts);
         if (ret < 0)
             return ret;
     }
 
     if (c->window_size || (final && c->remove_at_exit)) {
         int remove = os->nb_fragments - c->window_size - c->extra_window_size;
         if (final && c->remove_at_exit)
             remove = os->nb_fragments;
         if (remove > 0) {
             for (i = 0; i < remove; i++) {
                 unlink(os->fragments[i]->file);

                 av_freep(&os->fragments[i]);

             }
             os->nb_fragments -= remove;
             memmove(os->fragments, os->fragments + remove,
                     os->nb_fragments * sizeof(*os->fragments));
         }
     }
 
     if (ret >= 0)
         ret = write_abst(s, os, final);
     return ret;
 }
 
 static int hds_write_packet(AVFormatContext *s, AVPacket *pkt)
 {
     HDSContext *c = s->priv_data;
     AVStream *st = s->streams[pkt->stream_index];
     OutputStream *os = &c->streams[s->streams[pkt->stream_index]->id];

     int64_t end_dts = os->fragment_index * (int64_t)c->min_frag_duration;

     int ret;
 
     if (st->first_dts == AV_NOPTS_VALUE)
         st->first_dts = pkt->dts;
 
     if ((!os->has_video || st->codec->codec_type == AVMEDIA_TYPE_VIDEO) &&
         av_compare_ts(pkt->dts - st->first_dts, st->time_base,
                       end_dts, AV_TIME_BASE_Q) >= 0 &&
         pkt->flags & AV_PKT_FLAG_KEY && os->packets_written) {
 
         if ((ret = hds_flush(s, os, 0, pkt->dts)) < 0)
             return ret;
     }
 
     // Note, these fragment start timestamps, that represent a whole
     // OutputStream, assume all streams in it have the same time base.
     if (!os->packets_written)
         os->frag_start_ts = pkt->dts;
     os->last_ts = pkt->dts;
 
     os->packets_written++;

     return ff_write_chained(os->ctx, pkt->stream_index - os->first_stream, pkt, s, 0);

 }
 
 static int hds_write_trailer(AVFormatContext *s)
 {
     HDSContext *c = s->priv_data;
     int i;
 
     for (i = 0; i < c->nb_streams; i++)
         hds_flush(s, &c->streams[i], 1, c->streams[i].last_ts);
     write_manifest(s, 1);
 
     if (c->remove_at_exit) {
         char filename[1024];
         snprintf(filename, sizeof(filename), "%s/index.f4m", s->filename);
         unlink(filename);
         for (i = 0; i < c->nb_streams; i++) {
             snprintf(filename, sizeof(filename), "%s/stream%d.abst", s->filename, i);
             unlink(filename);
         }
         rmdir(s->filename);
     }
 
     hds_free(s);
     return 0;
 }
 
 #define OFFSET(x) offsetof(HDSContext, x)
 #define E AV_OPT_FLAG_ENCODING_PARAM
 static const AVOption options[] = {
     { "window_size", "number of fragments kept in the manifest", OFFSET(window_size), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, INT_MAX, E },
     { "extra_window_size", "number of fragments kept outside of the manifest before removing from disk", OFFSET(extra_window_size), AV_OPT_TYPE_INT, { .i64 = 5 }, 0, INT_MAX, E },
     { "min_frag_duration", "minimum fragment duration (in microseconds)", OFFSET(min_frag_duration), AV_OPT_TYPE_INT64, { .i64 = 10000000 }, 0, INT_MAX, E },
     { "remove_at_exit", "remove all fragments when finished", OFFSET(remove_at_exit), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, 1, E },
     { NULL },
 };
 
 static const AVClass hds_class = {
     .class_name = "HDS muxer",
     .item_name  = av_default_item_name,
     .option     = options,
     .version    = LIBAVUTIL_VERSION_INT,
 };
 
 AVOutputFormat ff_hds_muxer = {
     .name           = "hds",
     .long_name      = NULL_IF_CONFIG_SMALL("HDS Muxer"),
     .priv_data_size = sizeof(HDSContext),
     .audio_codec    = AV_CODEC_ID_AAC,
     .video_codec    = AV_CODEC_ID_H264,
     .flags          = AVFMT_GLOBALHEADER | AVFMT_NOFILE,
     .write_header   = hds_write_header,
     .write_packet   = hds_write_packet,
     .write_trailer  = hds_write_trailer,
     .priv_class     = &hds_class,
 };