/*

 * 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

 * JACOsub subtitle demuxer

 * @see http://unicorn.us.com/jacosub/jscripts.html

 * @todo Support P[ALETTE] directive.

 */

#include "avformat.h"

#include "demux.h"

#include "internal.h"

#include "subtitles.h"

#include "libavcodec/jacosub.h"

#include "libavutil/avstring.h"

#include "libavutil/bprint.h"

#include "libavutil/intreadwrite.h"

typedef struct {

    FFDemuxSubtitlesQueue q;

    int shift;

    unsigned timeres;

} JACOsubContext;

static int timed_line(const char *ptr)

{

    char c;

    int fs, fe;

    return (sscanf(ptr, "%*u:%*u:%*u.%*u %*u:%*u:%*u.%*u %c", &c) == 1 ||

            (sscanf(ptr, "@%u @%u %c", &fs, &fe, &c) == 3 && fs < fe));

}

static int jacosub_probe(const AVProbeData *p)

{

    const char *ptr     = p->buf;

    const char *ptr_end = p->buf + p->buf_size;

    if (AV_RB24(ptr) == 0xEFBBBF)

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

    while (ptr < ptr_end) {

        while (jss_whitespace(*ptr))

            ptr++;

        if (*ptr != '#' && *ptr != '\n') {

            if (timed_line(ptr))

                return AVPROBE_SCORE_EXTENSION + 1;

            return 0;

        }

        ptr += ff_subtitles_next_line(ptr);

    }

    return 0;

}

static const char * const cmds[] = {

    "CLOCKPAUSE",

    "DIRECTIVE",

    "FONT",

    "HRES",

    "INCLUDE",

    "PALETTE",

    "QUANTIZE",

    "RAMP",

    "SHIFT",

    "TIMERES",

};

static int get_jss_cmd(char k)

{

    int i;

    k = av_toupper(k);

    for (i = 0; i < FF_ARRAY_ELEMS(cmds); i++)

        if (k == cmds[i][0])

            return i;

    return -1;

}

static const char *read_ts(JACOsubContext *jacosub, const char *buf,

                           int64_t *start, int64_t *duration)

{

    int len;

    unsigned hs, ms, ss, fs; // hours, minutes, seconds, frame start

    unsigned he, me, se, fe; // hours, minutes, seconds, frame end

    int ts_start, ts_end;

    int64_t ts_start64, ts_end64;

    /* timed format */

    if (sscanf(buf, "%u:%u:%u.%u %u:%u:%u.%u %n",

               &hs, &ms, &ss, &fs,

               &he, &me, &se, &fe, &len) == 8) {

        ts_start = (hs*3600 + ms*60 + ss) * jacosub->timeres + fs;

        ts_end   = (he*3600 + me*60 + se) * jacosub->timeres + fe;

        goto shift_and_ret;

    }

    /* timestamps format */

    if (sscanf(buf, "@%u @%u %n", &ts_start, &ts_end, &len) == 2)

        goto shift_and_ret;

    return NULL;

shift_and_ret:

    ts_start64  = (ts_start + (int64_t)jacosub->shift) * 100LL / jacosub->timeres;

    ts_end64    = (ts_end   + (int64_t)jacosub->shift) * 100LL / jacosub->timeres;

    *start    = ts_start64;

    *duration = ts_end64 - ts_start64;

    return buf + len;

}

static int get_shift(unsigned timeres, const char *buf)

{

    int sign = 1;

    int h = 0, m = 0, s = 0, d = 0;

    int64_t ret;

#define SSEP "%*1[.:]"

    int n = sscanf(buf, "%d"SSEP"%d"SSEP"%d"SSEP"%d", &h, &m, &s, &d);

#undef SSEP

    if (h == INT_MIN)

        return 0;

    if (*buf == '-' || h < 0) {

        sign = -1;

        h = FFABS(h);

    }

    ret = 0;

    switch (n) {

    case 1:        h = 0;                   //clear all in case of a single parameter

    case 2: s = m; m = h; h = 0;            //shift into second subsecondd

    case 3: d = s; s = m; m = h; h = 0;     //shift into minute second subsecond

    }

    ret = (int64_t)h*3600 + (int64_t)m*60 + s;

    if (FFABS(ret) > (INT64_MAX - FFABS((int64_t)d)) / timeres)

        return 0;

    ret = sign * (ret * timeres + d);

    if ((int)ret != ret)

        ret = 0;

    return ret;

}

static int jacosub_read_header(AVFormatContext *s)

{

    AVBPrint header;

    AVIOContext *pb = s->pb;

    char line[JSS_MAX_LINESIZE];

    JACOsubContext *jacosub = s->priv_data;

    int shift_set = 0; // only the first shift matters

    int merge_line = 0;

    int i, ret;

    AVStream *st = avformat_new_stream(s, NULL);

    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_JACOSUB;

    jacosub->timeres = 30;

    av_bprint_init(&header, 1024+AV_INPUT_BUFFER_PADDING_SIZE, 4096);

    while (!avio_feof(pb)) {

        int cmd_len;

        const char *p = line;

        int64_t pos = avio_tell(pb);

        int len = ff_get_line(pb, line, sizeof(line));

        p = jss_skip_whitespace(p);

        /* queue timed line */

        if (merge_line || timed_line(p)) {

            AVPacket *sub;

            sub = ff_subtitles_queue_insert(&jacosub->q, line, len, merge_line);

            if (!sub) {

                av_bprint_finalize(&header, NULL);

                return AVERROR(ENOMEM);

            }

            sub->pos = pos;

            merge_line = len > 1 && !strcmp(&line[len - 2], "\\\n");

            continue;

        }

        /* skip all non-compiler commands and focus on the command */

        if (*p != '#')

            continue;

        p++;

        i = get_jss_cmd(p[0]);

        if (i == -1)

            continue;

        /* trim command + spaces */

        cmd_len = strlen(cmds[i]);

        if (av_strncasecmp(p, cmds[i], cmd_len) == 0)

            p += cmd_len;

        else

            p++;

        p = jss_skip_whitespace(p);

        /* handle commands which affect the whole script */

        switch (cmds[i][0]) {

        case 'S': // SHIFT command affect the whole script...

            if (!shift_set) {

                jacosub->shift = get_shift(jacosub->timeres, p);

                shift_set = 1;

            }

            av_bprintf(&header, "#S %s", p);

            break;

        case 'T': { // ...but must be placed after TIMERES

            int64_t timeres = strtol(p, NULL, 10);

            if (timeres <= 0 || timeres > UINT32_MAX) {

                jacosub->timeres = 30;

            } else {

                jacosub->timeres = timeres;

                av_bprintf(&header, "#T %s", p);

            }

            break;

        }

        }

    }

    /* general/essential directives in the extradata */

    ret = ff_bprint_to_codecpar_extradata(st->codecpar, &header);

    if (ret < 0)

        return ret;

    /* SHIFT and TIMERES affect the whole script so packet timing can only be

     * done in a second pass */

    for (i = 0; i < jacosub->q.nb_subs; i++) {

        AVPacket *sub = jacosub->q.subs[i];

        read_ts(jacosub, sub->data, &sub->pts, &sub->duration);

    }

    ff_subtitles_queue_finalize(s, &jacosub->q);

    return 0;

}

const FFInputFormat ff_jacosub_demuxer = {

    .p.name         = "jacosub",

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

    .priv_data_size = sizeof(JACOsubContext),

    .flags_internal = FF_INFMT_FLAG_INIT_CLEANUP,

    .read_probe     = jacosub_probe,

    .read_header    = jacosub_read_header,

    .read_packet    = ff_subtitles_read_packet,

    .read_seek2     = ff_subtitles_read_seek,

    .read_close     = ff_subtitles_read_close,

};