/*

 * Copyright (c) 2012 Clément Bœsch

 *

 * 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

 * RealText subtitle demuxer

 * @see http://service.real.com/help/library/guides/ProductionGuide/prodguide/htmfiles/realtext.htm

 */

#include "avformat.h"

#include "demux.h"

#include "internal.h"

#include "subtitles.h"

#include "libavutil/avstring.h"

#include "libavutil/bprint.h"

#include "libavutil/mem.h"

typedef struct {

    FFDemuxSubtitlesQueue q;

} RealTextContext;

static int realtext_probe(const AVProbeData *p)

{

    char buf[7];

    FFTextReader tr;

    ff_text_init_buf(&tr, p->buf, p->buf_size);

    ff_text_read(&tr, buf, sizeof(buf));

    return !av_strncasecmp(buf, "<window", 7) ? AVPROBE_SCORE_EXTENSION : 0;

}

static int64_t read_ts(const char *s)

{

    int hh, mm, ss, ms;

    if (sscanf(s, "%u:%u:%u.%u", &hh, &mm, &ss, &ms) == 4) return (hh*3600LL + mm*60LL + ss) * 100LL + ms;

    if (sscanf(s, "%u:%u:%u"   , &hh, &mm, &ss     ) == 3) return (hh*3600LL + mm*60LL + ss) * 100LL;

    if (sscanf(s,    "%u:%u.%u",      &mm, &ss, &ms) == 3) return (            mm*60LL + ss) * 100LL + ms;

    if (sscanf(s,    "%u:%u"   ,      &mm, &ss     ) == 2) return (            mm*60LL + ss) * 100LL;

    if (sscanf(s,       "%u.%u",           &ss, &ms) == 2) return (                      ss) * 100LL + ms;

    return strtoll(s, NULL, 10) * 100ULL;

}

static int realtext_read_header(AVFormatContext *s)

{

    RealTextContext *rt = s->priv_data;

    AVStream *st = avformat_new_stream(s, NULL);

    AVBPrint buf;

    char c = 0;

    int res = 0, duration = read_ts("60"); // default duration is 60 seconds

    FFTextReader tr;

    ff_text_init_avio(s, &tr, s->pb);

    if (!st)

        return AVERROR(ENOMEM);

    avpriv_set_pts_info(st, 64, 1, 100);

    st->codecpar->codec_type = AVMEDIA_TYPE_SUBTITLE;

    st->codecpar->codec_id   = AV_CODEC_ID_REALTEXT;

    av_bprint_init(&buf, 0, AV_BPRINT_SIZE_UNLIMITED);

    while (!ff_text_eof(&tr)) {

        AVPacket *sub;

        const int64_t pos = ff_text_pos(&tr) - (c != 0);

        int n = ff_smil_extract_next_text_chunk(&tr, &buf, &c);

        if (n < 0) {

            res = n;

            goto end;

        }

        if (n == 0)

            break;

        if (!av_strncasecmp(buf.str, "<window", 7)) {

            /* save header to extradata */

            const char *p = ff_smil_get_attr_ptr(buf.str, "duration");

            if (st->codecpar->extradata) {

                res = AVERROR_INVALIDDATA;

                goto end;

            }

            if (p)

                duration = read_ts(p);

            st->codecpar->extradata = av_strdup(buf.str);

            if (!st->codecpar->extradata) {

                res = AVERROR(ENOMEM);

                goto end;

            }

            st->codecpar->extradata_size = buf.len + 1;

        } else {

            /* if we just read a <time> tag, introduce a new event, otherwise merge

             * with the previous one */

            int merge = !av_strncasecmp(buf.str, "<time", 5) ? 0 : 1;

            sub = ff_subtitles_queue_insert_bprint(&rt->q, &buf, merge);

            if (!sub) {

                res = AVERROR(ENOMEM);

                goto end;

            }

            if (!merge) {

                const char *begin = ff_smil_get_attr_ptr(buf.str, "begin");

                const char *end   = ff_smil_get_attr_ptr(buf.str, "end");

                int64_t endi = end ? read_ts(end) : 0;

                sub->pos      = pos;

                sub->pts      = begin ? read_ts(begin) : 0;

                sub->duration = (end && endi > sub->pts && endi - (uint64_t)sub->pts <= INT64_MAX) ? endi - sub->pts : duration;

            }

        }

        av_bprint_clear(&buf);

    }

    ff_subtitles_queue_finalize(s, &rt->q);

end:

    av_bprint_finalize(&buf, NULL);

    return res;

}

const FFInputFormat ff_realtext_demuxer = {

    .p.name         = "realtext",

    .p.long_name    = NULL_IF_CONFIG_SMALL("RealText subtitle format"),

    .p.extensions   = "rt",

    .priv_data_size = sizeof(RealTextContext),

    .flags_internal = FF_INFMT_FLAG_INIT_CLEANUP,

    .read_probe     = realtext_probe,

    .read_header    = realtext_read_header,

    .read_packet    = ff_subtitles_read_packet,

    .read_seek2     = ff_subtitles_read_seek,

    .read_close     = ff_subtitles_read_close,

};