/*
  * Copyright (c) 2014 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 <stdio.h>
 #include <string.h>
 
 #include "libavformat/avformat.h"
 #include "libavutil/avstring.h"
 #include "libavutil/intreadwrite.h"
 #include "libavutil/mathematics.h"
 
 static int usage(const char *argv0, int ret)
 {
     fprintf(stderr, "%s -out foo.mpd file1\n", argv0);
     return ret;
 }
 
 struct Track {
     const char *name;
     int64_t duration;
     int bitrate;
     int track_id;
     int is_audio, is_video;
     int width, height;
     int sample_rate, channels;
     int timescale;
     char codec_str[30];
     int64_t sidx_start, sidx_length;
     int64_t  earliest_presentation;
     uint32_t earliest_presentation_timescale;
 };
 
 struct Tracks {
     int nb_tracks;
     int64_t duration;
     struct Track **tracks;
     int multiple_tracks_per_file;
 };
 
 static void set_codec_str(AVCodecContext *codec, char *str, int size)
 {
     switch (codec->codec_id) {
     case AV_CODEC_ID_H264:
         snprintf(str, size, "avc1");
         if (codec->extradata_size >= 4 && codec->extradata[0] == 1) {
             av_strlcatf(str, size, ".%02x%02x%02x",
                         codec->extradata[1], codec->extradata[2], codec->extradata[3]);
         }
         break;
     case AV_CODEC_ID_AAC:
         snprintf(str, size, "mp4a.40"); // 0x40 is the mp4 object type for AAC
         if (codec->extradata_size >= 2) {
             int aot = codec->extradata[0] >> 3;
             if (aot == 31)
                 aot = ((AV_RB16(codec->extradata) >> 5) & 0x3f) + 32;
             av_strlcatf(str, size, ".%d", aot);
         }
         break;
     }
 }
 
 static int find_sidx(struct Tracks *tracks, int start_index,
                      const char *file)
 {
     int err = 0;
     AVIOContext *f = NULL;
     int i;
 
     if ((err = avio_open2(&f, file, AVIO_FLAG_READ, NULL, NULL)) < 0)
         goto fail;
 
     while (!f->eof_reached) {
         int64_t pos = avio_tell(f);
         int32_t size, tag;
 
         size = avio_rb32(f);
         tag  = avio_rb32(f);
         if (size < 8)
             break;
         if (tag == MKBETAG('s', 'i', 'd', 'x')) {
             int version, track_id;
             uint32_t timescale;
             int64_t earliest_presentation;
             version = avio_r8(f);
             avio_rb24(f); /* flags */
             track_id = avio_rb32(f);
             timescale = avio_rb32(f);
             earliest_presentation = version ? avio_rb64(f) : avio_rb32(f);
             for (i = start_index; i < tracks->nb_tracks; i++) {
                 struct Track *track = tracks->tracks[i];
                 if (!track->sidx_start) {
                     track->sidx_start  = pos;
                     track->sidx_length = size;
                 } else if (pos == track->sidx_start + track->sidx_length) {
                     track->sidx_length = pos + size - track->sidx_start;
                 }
                 if (track->track_id == track_id) {
                     track->earliest_presentation = earliest_presentation;
                     track->earliest_presentation_timescale = timescale;
                 }
             }
         }
         if (avio_seek(f, pos + size, SEEK_SET) != pos + size)
             break;
     }
 
 fail:
     if (f)
         avio_close(f);
     return err;
 }
 
 static int handle_file(struct Tracks *tracks, const char *file)
 {
     AVFormatContext *ctx = NULL;
     int err = 0, i, orig_tracks = tracks->nb_tracks;
     char errbuf[50], *ptr;
     struct Track *track;
 
     err = avformat_open_input(&ctx, file, NULL, NULL);
     if (err < 0) {
         av_strerror(err, errbuf, sizeof(errbuf));
         fprintf(stderr, "Unable to open %s: %s\n", file, errbuf);
         return 1;
     }
 
     err = avformat_find_stream_info(ctx, NULL);
     if (err < 0) {
         av_strerror(err, errbuf, sizeof(errbuf));
         fprintf(stderr, "Unable to identify %s: %s\n", file, errbuf);
         goto fail;
     }
 
     if (ctx->nb_streams < 1) {
         fprintf(stderr, "No streams found in %s\n", file);
         goto fail;
     }
     if (ctx->nb_streams > 1)
         tracks->multiple_tracks_per_file = 1;
 
     for (i = 0; i < ctx->nb_streams; i++) {
         struct Track **temp;
         AVStream *st = ctx->streams[i];
 
         if (st->codec->bit_rate == 0) {
             fprintf(stderr, "Skipping track %d in %s as it has zero bitrate\n",
                     st->id, file);
             continue;
         }
 
         track = av_mallocz(sizeof(*track));
         if (!track) {
             err = AVERROR(ENOMEM);
             goto fail;
         }
         temp = av_realloc(tracks->tracks,
                           sizeof(*tracks->tracks) * (tracks->nb_tracks + 1));
         if (!temp) {
             av_free(track);
             err = AVERROR(ENOMEM);
             goto fail;
         }
         tracks->tracks = temp;
         tracks->tracks[tracks->nb_tracks] = track;
 
         track->name = file;
         if ((ptr = strrchr(file, '/')))
             track->name = ptr + 1;
 
         track->bitrate   = st->codec->bit_rate;
         track->track_id  = st->id;
         track->timescale = st->time_base.den;
         track->duration  = st->duration;
         track->is_audio  = st->codec->codec_type == AVMEDIA_TYPE_AUDIO;
         track->is_video  = st->codec->codec_type == AVMEDIA_TYPE_VIDEO;
 
         if (!track->is_audio && !track->is_video) {
             fprintf(stderr,
                     "Track %d in %s is neither video nor audio, skipping\n",
                     track->track_id, file);
             av_freep(&tracks->tracks[tracks->nb_tracks]);
             continue;
         }
 
         tracks->duration = FFMAX(tracks->duration,
                                  av_rescale_rnd(track->duration, AV_TIME_BASE,
                                                 track->timescale, AV_ROUND_UP));
 
         if (track->is_audio) {
             track->channels    = st->codec->channels;
             track->sample_rate = st->codec->sample_rate;
         }
         if (track->is_video) {
             track->width  = st->codec->width;
             track->height = st->codec->height;
         }
         set_codec_str(st->codec, track->codec_str, sizeof(track->codec_str));
 
         tracks->nb_tracks++;
     }
 
     avformat_close_input(&ctx);
 
     err = find_sidx(tracks, orig_tracks, file);
 
 fail:
     if (ctx)
         avformat_close_input(&ctx);
     return err;
 }
 
 static void write_time(FILE *out, int64_t time, int decimals, enum AVRounding round)
 {
     int seconds = time / AV_TIME_BASE;
     int fractions = time % AV_TIME_BASE;
     int minutes = seconds / 60;
     int hours = minutes / 60;
     fractions = av_rescale_rnd(fractions, pow(10, decimals), AV_TIME_BASE, round);
     seconds %= 60;
     minutes %= 60;
     fprintf(out, "PT");
     if (hours)
         fprintf(out, "%dH", hours);
     if (hours || minutes)
         fprintf(out, "%dM", minutes);
     fprintf(out, "%d.%0*dS", seconds, decimals, fractions);
 }
 
 static int output_mpd(struct Tracks *tracks, const char *filename)
 {
     FILE *out;
     int i, j, ret = 0;
     struct Track **adaptation_sets_buf[2] = { NULL };
     struct Track ***adaptation_sets;
     int nb_tracks_buf[2] = { 0 };
     int *nb_tracks;
     int set, nb_sets;
     int64_t latest_start = 0;
 
     if (!tracks->multiple_tracks_per_file) {
         adaptation_sets = adaptation_sets_buf;
         nb_tracks = nb_tracks_buf;
         nb_sets = 2;
         for (i = 0; i < 2; i++) {
             adaptation_sets[i] = av_malloc(sizeof(*adaptation_sets[i]) * tracks->nb_tracks);
             if (!adaptation_sets[i]) {
                 ret = AVERROR(ENOMEM);
                 goto err;
             }
         }
         for (i = 0; i < tracks->nb_tracks; i++) {
             int set_index = -1;
             if (tracks->tracks[i]->is_video)
                 set_index = 0;
             else if (tracks->tracks[i]->is_audio)
                 set_index = 1;
             else
                 continue;
             adaptation_sets[set_index][nb_tracks[set_index]++] = tracks->tracks[i];
         }
     } else {
         adaptation_sets = &tracks->tracks;
         nb_tracks = &tracks->nb_tracks;
         nb_sets = 1;
     }
 
     out = fopen(filename, "w");
     if (!out) {
         ret = AVERROR(errno);
         perror(filename);
         return ret;
     }
     fprintf(out, "<?xml version=\"1.0\" encoding=\"utf-8\"?>\n");
     fprintf(out, "<MPD xmlns:xsi=\"http://www.w3.org/2001/XMLSchema-instance\"\n"
                 "\txmlns=\"urn:mpeg:dash:schema:mpd:2011\"\n"
                 "\txmlns:xlink=\"http://www.w3.org/1999/xlink\"\n"
                 "\txsi:schemaLocation=\"urn:mpeg:DASH:schema:MPD:2011 http://standards.iso.org/ittf/PubliclyAvailableStandards/MPEG-DASH_schema_files/DASH-MPD.xsd\"\n"
                 "\tprofiles=\"urn:mpeg:dash:profile:isoff-on-demand:2011\"\n"
                 "\ttype=\"static\"\n");
     fprintf(out, "\tmediaPresentationDuration=\"");
     write_time(out, tracks->duration, 1, AV_ROUND_DOWN);
     fprintf(out, "\"\n");
     fprintf(out, "\tminBufferTime=\"PT5S\">\n");
 
     for (i = 0; i < tracks->nb_tracks; i++) {
         int64_t start = av_rescale_rnd(tracks->tracks[i]->earliest_presentation,
                                        AV_TIME_BASE,
                                        tracks->tracks[i]->earliest_presentation_timescale,
                                        AV_ROUND_UP);
         latest_start = FFMAX(start, latest_start);
     }
     fprintf(out, "\t<Period start=\"");
     write_time(out, latest_start, 3, AV_ROUND_UP);
     fprintf(out, "\">\n");
 
 
     for (set = 0; set < nb_sets; set++) {
         if (nb_tracks[set] == 0)
             continue;
         fprintf(out, "\t\t<AdaptationSet segmentAlignment=\"true\">\n");
         if (nb_sets == 1) {
             for (i = 0; i < nb_tracks[set]; i++) {
                 struct Track *track = adaptation_sets[set][i];
                 if (strcmp(track->name, adaptation_sets[set][0]->name))
                     break;
                 fprintf(out, "\t\t\t<ContentComponent id=\"%d\" contentType=\"%s\" />\n", track->track_id, track->is_audio ? "audio" : "video");
             }
         }
 
         for (i = 0; i < nb_tracks[set]; ) {
             struct Track *first_track = adaptation_sets[set][i];
             int width = 0, height = 0, sample_rate = 0, channels = 0, bitrate = 0;

             fprintf(out, "\t\t\t<Representation id=\"%d\" codecs=\"", i);

             for (j = i; j < nb_tracks[set]; j++) {
                 struct Track *track = adaptation_sets[set][j];
                 if (strcmp(track->name, first_track->name))
                     break;
                 if (track->is_audio) {
                     sample_rate = track->sample_rate;
                     channels = track->channels;
                 }
                 if (track->is_video) {
                     width = track->width;
                     height = track->height;
                 }
                 bitrate += track->bitrate;
                 if (j > i)
                     fprintf(out, ",");
                 fprintf(out, "%s", track->codec_str);
             }

             fprintf(out, "\" mimeType=\"%s/mp4\" bandwidth=\"%d\"",
                     width ? "video" : "audio", bitrate);

             if (width > 0 && height > 0)
                 fprintf(out, " width=\"%d\" height=\"%d\"", width, height);
             if (sample_rate > 0)
                 fprintf(out, " audioSamplingRate=\"%d\"", sample_rate);
             fprintf(out, ">\n");
             if (channels > 0)
                 fprintf(out, "\t\t\t\t<AudioChannelConfiguration schemeIdUri=\"urn:mpeg:dash:23003:3:audio_channel_configuration:2011\" value=\"%d\" />\n", channels);
             fprintf(out, "\t\t\t\t<BaseURL>%s</BaseURL>\n", first_track->name);
             fprintf(out, "\t\t\t\t<SegmentBase indexRange=\"%"PRId64"-%"PRId64"\" />\n", first_track->sidx_start, first_track->sidx_start + first_track->sidx_length - 1);
             fprintf(out, "\t\t\t</Representation>\n");
             i = j;
         }
         fprintf(out, "\t\t</AdaptationSet>\n");
     }
     fprintf(out, "\t</Period>\n");
     fprintf(out, "</MPD>\n");
 
     fclose(out);
 err:
     for (i = 0; i < 2; i++)
         av_free(adaptation_sets_buf[i]);
     return ret;
 }
 
 static void clean_tracks(struct Tracks *tracks)
 {
     int i;
     for (i = 0; i < tracks->nb_tracks; i++) {
         av_freep(&tracks->tracks[i]);
     }
     av_freep(&tracks->tracks);
     tracks->nb_tracks = 0;
 }
 
 int main(int argc, char **argv)
 {
     const char *out = NULL;
     struct Tracks tracks = { 0 };
     int i;
 
     av_register_all();
 
     for (i = 1; i < argc; i++) {
         if (!strcmp(argv[i], "-out")) {
             out = argv[i + 1];
             i++;
         } else if (argv[i][0] == '-') {
             return usage(argv[0], 1);
         } else {
             if (handle_file(&tracks, argv[i]))
                 return 1;
         }
     }
     if (!tracks.nb_tracks || !out)
         return usage(argv[0], 1);
 
     output_mpd(&tracks, out);
 
     clean_tracks(&tracks);
 
     return 0;
 }