/*

 * MicroDVD subtitle demuxer

 * Copyright (c) 2010  Aurelien Jacobs <aurel@gnuage.org>

 * Copyright (c) 2012  Clément Bœsch <u pkh me>

 *

 * 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 "avformat.h"

#include "demux.h"

#include "internal.h"

#include "subtitles.h"

#include "libavutil/intreadwrite.h"

#include "libavutil/opt.h"

#define MAX_LINESIZE 2048

typedef struct {

    const AVClass *class;

    FFDemuxSubtitlesQueue q;

    AVRational frame_rate;

} MicroDVDContext;

static int microdvd_probe(const AVProbeData *p)

{

    unsigned char c;

    const uint8_t *ptr = p->buf;

    int i;

    if (AV_RB24(ptr) == 0xEFBBBF)

        ptr += 3;  /* skip UTF-8 BOM */

    for (i=0; i<3; i++) {

        if (sscanf(ptr, "{%*d}{}%c",     &c) != 1 &&

            sscanf(ptr, "{%*d}{%*d}%c",  &c) != 1 &&

            sscanf(ptr, "{DEFAULT}{}%c", &c) != 1)

            return 0;

        ptr += ff_subtitles_next_line(ptr);

    }

    return AVPROBE_SCORE_MAX;

}

static int64_t get_pts(const char *buf)

{

    int frame;

    char c;

    if (sscanf(buf, "{%d}{%c", &frame, &c) == 2)

        return frame;

    return AV_NOPTS_VALUE;

}

static int64_t get_duration(const char *buf)

{

    int frame_start, frame_end;

    if (sscanf(buf, "{%d}{%d}", &frame_start, &frame_end) == 2)

        return frame_end - (int64_t)frame_start;

    return -1;

}

static const char *bom = "\xEF\xBB\xBF";

static int microdvd_read_header(AVFormatContext *s)

{

    AVRational pts_info = (AVRational){ 2997, 125 };  /* default: 23.976 fps */

    MicroDVDContext *microdvd = s->priv_data;

    AVStream *st = avformat_new_stream(s, NULL);

    int i = 0, ret;

    char line_buf[MAX_LINESIZE];

    int has_real_fps = 0;

    if (!st)

        return AVERROR(ENOMEM);

    while (!avio_feof(s->pb)) {

        char *p;

        AVPacket *sub;

        int64_t pos = avio_tell(s->pb);

        int len = ff_get_line(s->pb, line_buf, sizeof(line_buf));

        char *line = line_buf;

        int64_t pts;

        if (!strncmp(line, bom, 3))

            line += 3;

        p = line;

        if (!len)

            break;

        line[strcspn(line, "\r\n")] = 0;

        if (!*p)

            continue;

        if (i++ < 3) {

            int frame;

            double fps;

            char c;

            if ((sscanf(line, "{%d}{}%6lf",    &frame, &fps) == 2 ||

                 sscanf(line, "{%d}{%*d}%6lf", &frame, &fps) == 2)

                && frame <= 1 && fps > 3 && fps < 100) {

                pts_info = av_d2q(fps, 100000);

                has_real_fps = 1;

                continue;

            }

            if (!st->codecpar->extradata && sscanf(line, "{DEFAULT}{}%c", &c) == 1) {

                int size = strlen(line + 11);

                ret = ff_alloc_extradata(st->codecpar, size);

                if (ret < 0)

                    return ret;

                memcpy(st->codecpar->extradata, line + 11, size);

                continue;

            }

        }

#define SKIP_FRAME_ID                                       \

    p = strchr(p, '}');                                     \

    if (!p) {                                               \

        av_log(s, AV_LOG_WARNING, "Invalid event \"%s\""    \

               " at line %d\n", line, i);                   \

        continue;                                           \

    }                                                       \

    p++

        SKIP_FRAME_ID;

        SKIP_FRAME_ID;

        if (!*p)

            continue;

        pts = get_pts(line);

        if (pts == AV_NOPTS_VALUE)

            continue;

        sub = ff_subtitles_queue_insert(&microdvd->q, p, strlen(p), 0);

        if (!sub)

            return AVERROR(ENOMEM);

        sub->pos = pos;

        sub->pts = pts;

        sub->duration = get_duration(line);

    }

    ff_subtitles_queue_finalize(s, &microdvd->q);

    if (has_real_fps) {

        /* export the FPS info only if set in the file */

        microdvd->frame_rate = pts_info;

    } else if (microdvd->frame_rate.num) {

        /* fallback on user specified frame rate */

        pts_info = microdvd->frame_rate;

    }

    avpriv_set_pts_info(st, 64, pts_info.den, pts_info.num);

    st->codecpar->codec_type = AVMEDIA_TYPE_SUBTITLE;

    st->codecpar->codec_id   = AV_CODEC_ID_MICRODVD;

    return 0;

}

static int microdvd_read_packet(AVFormatContext *s, AVPacket *pkt)

{

    MicroDVDContext *microdvd = s->priv_data;

    return ff_subtitles_queue_read_packet(&microdvd->q, pkt);

}

static int microdvd_read_seek(AVFormatContext *s, int stream_index,

                             int64_t min_ts, int64_t ts, int64_t max_ts, int flags)

{

    MicroDVDContext *microdvd = s->priv_data;

    return ff_subtitles_queue_seek(&microdvd->q, s, stream_index,

                                   min_ts, ts, max_ts, flags);

}

static int microdvd_read_close(AVFormatContext *s)

{

    MicroDVDContext *microdvd = s->priv_data;

    ff_subtitles_queue_clean(&microdvd->q);

    return 0;

}

#define OFFSET(x) offsetof(MicroDVDContext, x)

#define SD AV_OPT_FLAG_SUBTITLE_PARAM|AV_OPT_FLAG_DECODING_PARAM

static const AVOption microdvd_options[] = {

    { "subfps", "set the movie frame rate fallback", OFFSET(frame_rate), AV_OPT_TYPE_RATIONAL, {.dbl=0}, 0, INT_MAX, SD },

    { NULL }

};

static const AVClass microdvd_class = {

    .class_name = "microdvddec",

    .item_name  = av_default_item_name,

    .option     = microdvd_options,

    .version    = LIBAVUTIL_VERSION_INT,

};

const FFInputFormat ff_microdvd_demuxer = {

    .p.name         = "microdvd",

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

    .p.priv_class   = &microdvd_class,

    .priv_data_size = sizeof(MicroDVDContext),

    .flags_internal = FF_INFMT_FLAG_INIT_CLEANUP,

    .read_probe     = microdvd_probe,

    .read_header    = microdvd_read_header,

    .read_packet    = microdvd_read_packet,

    .read_seek2     = microdvd_read_seek,

    .read_close     = microdvd_read_close,

};