/*

 * Copyright (c) 2012-2013 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 "subtitles.h"

#include "avio_internal.h"

#include "libavutil/avassert.h"

#include "libavutil/avstring.h"

#include "libavutil/mem.h"

void ff_text_init_avio(void *s, FFTextReader *r, AVIOContext *pb)

{

    int i;

    r->pb = pb;

    r->buf_pos = r->buf_len = 0;

    r->type = FF_UTF_8;

    for (i = 0; i < 2; i++)

        r->buf[r->buf_len++] = avio_r8(r->pb);

    if (strncmp("\xFF\xFE", r->buf, 2) == 0) {

        r->type = FF_UTF16LE;

        r->buf_pos += 2;

    } else if (strncmp("\xFE\xFF", r->buf, 2) == 0) {

        r->type = FF_UTF16BE;

        r->buf_pos += 2;

    } else {

        r->buf[r->buf_len++] = avio_r8(r->pb);

        if (strncmp("\xEF\xBB\xBF", r->buf, 3) == 0) {

            // UTF8

            r->buf_pos += 3;

        }

    }

    if (s && (r->type == FF_UTF16LE || r->type == FF_UTF16BE))

        av_log(s, AV_LOG_INFO,

               "UTF16 is automatically converted to UTF8, do not specify a character encoding\n");

}

void ff_text_init_buf(FFTextReader *r, const void *buf, size_t size)

{

    ffio_init_read_context(&r->buf_pb, buf, size);

    ff_text_init_avio(NULL, r, &r->buf_pb.pub);

}

int64_t ff_text_pos(FFTextReader *r)

{

    return avio_tell(r->pb) - r->buf_len + r->buf_pos;

}

int ff_text_r8(FFTextReader *r)

{

    uint32_t val;

    uint8_t tmp;

    if (r->buf_pos < r->buf_len)

        return r->buf[r->buf_pos++];

    if (r->type == FF_UTF16LE) {

        GET_UTF16(val, avio_rl16(r->pb), return 0;)

    } else if (r->type == FF_UTF16BE) {

        GET_UTF16(val, avio_rb16(r->pb), return 0;)

    } else {

        return avio_r8(r->pb);

    }

    if (!val)

        return 0;

    r->buf_pos = 0;

    r->buf_len = 0;

    PUT_UTF8(val, tmp, r->buf[r->buf_len++] = tmp;)

    return r->buf[r->buf_pos++]; // buf_len is at least 1

}

void ff_text_read(FFTextReader *r, char *buf, size_t size)

{

    for ( ; size > 0; size--)

        *buf++ = ff_text_r8(r);

}

int ff_text_eof(FFTextReader *r)

{

    return r->buf_pos >= r->buf_len && avio_feof(r->pb);

}

int ff_text_peek_r8(FFTextReader *r)

{

    int c;

    if (r->buf_pos < r->buf_len)

        return r->buf[r->buf_pos];

    c = ff_text_r8(r);

    if (!avio_feof(r->pb)) {

        r->buf_pos = 0;

        r->buf_len = 1;

        r->buf[0] = c;

    }

    return c;

}

AVPacket *ff_subtitles_queue_insert(FFDemuxSubtitlesQueue *q,

                                    const uint8_t *event, size_t len, int merge)

{

    AVPacket **subs, *sub;

    av_assert1(event || len == 0);

    if (merge && q->nb_subs > 0) {

        /* merge with previous event */

        int old_len;

        sub = q->subs[q->nb_subs - 1];

        old_len = sub->size;

        if (event) {

            if (av_grow_packet(sub, len) < 0)

                return NULL;

            memcpy(sub->data + old_len, event, len);

        }

    } else {

        /* new event */

        if (q->nb_subs >= INT_MAX/sizeof(*q->subs) - 1)

            return NULL;

        subs = av_fast_realloc(q->subs, &q->allocated_size,

                               (q->nb_subs + 1) * sizeof(*q->subs));

        if (!subs)

            return NULL;

        q->subs = subs;

        sub = av_packet_alloc();

        if (!sub)

            return NULL;

        if (event) {

            if (av_new_packet(sub, len) < 0) {

                av_packet_free(&sub);

                return NULL;

            }

            memcpy(sub->data, event, len);

        }

        sub->flags |= AV_PKT_FLAG_KEY;

        sub->pts = sub->dts = 0;

        subs[q->nb_subs++] = sub;

    }

    return sub;

}

AVPacket *ff_subtitles_queue_insert_bprint(FFDemuxSubtitlesQueue *q,

                                           const AVBPrint *event, int merge)

{

    if (!av_bprint_is_complete(event))

        return NULL;

    return ff_subtitles_queue_insert(q, event->str, event->len, merge);

}

static int cmp_pkt_sub_ts_pos(const void *a, const void *b)

{

    const AVPacket *s1 = *(const AVPacket **)a;

    const AVPacket *s2 = *(const AVPacket **)b;

    if (s1->pts == s2->pts)

        return FFDIFFSIGN(s1->pos, s2->pos);

    return FFDIFFSIGN(s1->pts , s2->pts);

}

static int cmp_pkt_sub_pos_ts(const void *a, const void *b)

{

    const AVPacket *s1 = *(const AVPacket **)a;

    const AVPacket *s2 = *(const AVPacket **)b;

    if (s1->pos == s2->pos) {

        if (s1->pts == s2->pts)

            return 0;

        return s1->pts > s2->pts ? 1 : -1;

    }

    return s1->pos > s2->pos ? 1 : -1;

}

static void drop_dups(void *log_ctx, FFDemuxSubtitlesQueue *q)

{

    int i, drop = 0;

    for (i = 1; i < q->nb_subs; i++) {

        const int last_id = i - 1 - drop;

        const AVPacket *last = q->subs[last_id];

        if (q->subs[i]->pts        == last->pts &&

            q->subs[i]->duration   == last->duration &&

            q->subs[i]->stream_index == last->stream_index &&

            !strcmp(q->subs[i]->data, last->data)) {

            av_packet_free(&q->subs[i]);

            drop++;

        } else if (drop) {

            q->subs[last_id + 1] = q->subs[i];

            q->subs[i] = NULL;

        }

    }

    if (drop) {

        q->nb_subs -= drop;

        av_log(log_ctx, AV_LOG_WARNING, "Dropping %d duplicated subtitle events\n", drop);

    }

}

void ff_subtitles_queue_finalize(void *log_ctx, FFDemuxSubtitlesQueue *q)

{

    int i;

    if (!q->nb_subs)

        return;

    qsort(q->subs, q->nb_subs, sizeof(*q->subs),

          q->sort == SUB_SORT_TS_POS ? cmp_pkt_sub_ts_pos

                                     : cmp_pkt_sub_pos_ts);

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

        if (q->subs[i]->duration < 0 && i < q->nb_subs - 1 && q->subs[i + 1]->pts - (uint64_t)q->subs[i]->pts <= INT64_MAX)

            q->subs[i]->duration = q->subs[i + 1]->pts - q->subs[i]->pts;

    if (!q->keep_duplicates)

        drop_dups(log_ctx, q);

}

int ff_subtitles_queue_read_packet(FFDemuxSubtitlesQueue *q, AVPacket *pkt)

{

    AVPacket *sub;

    int ret;

    if (q->current_sub_idx == q->nb_subs)

        return AVERROR_EOF;

    sub = q->subs[q->current_sub_idx];

    if ((ret = av_packet_ref(pkt, sub)) < 0) {

        return ret;

    }

    pkt->dts = pkt->pts;

    q->current_sub_idx++;

    return 0;

}

static int search_sub_ts(const FFDemuxSubtitlesQueue *q, int64_t ts)

{

    int s1 = 0, s2 = q->nb_subs - 1;

    if (s2 < s1)

        return AVERROR(ERANGE);

    for (;;) {

        int mid;

        if (s1 == s2)

            return s1;

        if (s1 == s2 - 1)

            return q->subs[s1]->pts <= q->subs[s2]->pts ? s1 : s2;

        mid = (s1 + s2) / 2;

        if (q->subs[mid]->pts <= ts)

            s1 = mid;

        else

            s2 = mid;

    }

}

int ff_subtitles_queue_seek(FFDemuxSubtitlesQueue *q, AVFormatContext *s, int stream_index,

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

{

    if (flags & AVSEEK_FLAG_BYTE) {

        return AVERROR(ENOSYS);

    } else if (flags & AVSEEK_FLAG_FRAME) {

        if (ts < 0 || ts >= q->nb_subs)

            return AVERROR(ERANGE);

        q->current_sub_idx = ts;

    } else {

        int i, idx = search_sub_ts(q, ts);

        int64_t ts_selected;

        if (idx < 0)

            return idx;

        for (i = idx; i < q->nb_subs && q->subs[i]->pts < min_ts; i++)

            if (stream_index == -1 || q->subs[i]->stream_index == stream_index)

                idx = i;

        for (i = idx; i > 0 && q->subs[i]->pts > max_ts; i--)

            if (stream_index == -1 || q->subs[i]->stream_index == stream_index)

                idx = i;

        ts_selected = q->subs[idx]->pts;

        if (ts_selected < min_ts || ts_selected > max_ts)

            return AVERROR(ERANGE);

        /* look back in the latest subtitles for overlapping subtitles */

        for (i = idx - 1; i >= 0; i--) {

            int64_t pts = q->subs[i]->pts;

            if (q->subs[i]->duration <= 0 ||

                (stream_index != -1 && q->subs[i]->stream_index != stream_index))

                continue;

            if (pts >= min_ts && pts > ts_selected - q->subs[i]->duration)

                idx = i;

            else

                break;

        }

        /* If the queue is used to store multiple subtitles streams (like with

         * VobSub) and the stream index is not specified, we need to make sure

         * to focus on the smallest file position offset for a same timestamp;

         * queue is ordered by pts and then filepos, so we can take the first

         * entry for a given timestamp. */

        if (stream_index == -1)

            while (idx > 0 && q->subs[idx - 1]->pts == q->subs[idx]->pts)

                idx--;

        q->current_sub_idx = idx;

    }

    return 0;

}

void ff_subtitles_queue_clean(FFDemuxSubtitlesQueue *q)

{

    int i;

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

        av_packet_free(&q->subs[i]);

    av_freep(&q->subs);

    q->nb_subs = q->allocated_size = q->current_sub_idx = 0;

}

int ff_subtitles_read_packet(AVFormatContext *s, AVPacket *pkt)

{

    FFDemuxSubtitlesQueue *q = s->priv_data;

    return ff_subtitles_queue_read_packet(q, pkt);

}

int ff_subtitles_read_seek(AVFormatContext *s, int stream_index,

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

{

    FFDemuxSubtitlesQueue *q = s->priv_data;

    return ff_subtitles_queue_seek(q, s, stream_index,

                                   min_ts, ts, max_ts, flags);

}

int ff_subtitles_read_close(AVFormatContext *s)

{

    FFDemuxSubtitlesQueue *q = s->priv_data;

    ff_subtitles_queue_clean(q);

    return 0;

}

int ff_smil_extract_next_text_chunk(FFTextReader *tr, AVBPrint *buf, char *c)

{

    int i = 0;

    char end_chr;

    if (!*c) // cached char?

        *c = ff_text_r8(tr);

    if (!*c)

        return 0;

    end_chr = *c == '<' ? '>' : '<';

    do {

        av_bprint_chars(buf, *c, 1);

        *c = ff_text_r8(tr);

        if (i == INT_MAX)

            return AVERROR_INVALIDDATA;

        i++;

    } while (*c != end_chr && *c);

    if (end_chr == '>') {

        av_bprint_chars(buf, '>', 1);

        *c = 0;

    }

    return av_bprint_is_complete(buf) ? i : AVERROR(ENOMEM);

}

const char *ff_smil_get_attr_ptr(const char *s, const char *attr)

{

    int in_quotes = 0;

    const size_t len = strlen(attr);

    while (*s) {

        while (*s) {

            if (!in_quotes && av_isspace(*s))

                break;

            in_quotes ^= *s == '"'; // XXX: support escaping?

            s++;

        }

        while (av_isspace(*s))

            s++;

        if (!av_strncasecmp(s, attr, len) && s[len] == '=')

            return s + len + 1 + (s[len + 1] == '"');

    }

    return NULL;

}

static inline int is_eol(char c)

{

    return c == '\r' || c == '\n';

}

int ff_subtitles_read_text_chunk(FFTextReader *tr, AVBPrint *buf)

{

    char eol_buf[5], last_was_cr = 0;

    int n = 0, i = 0, nb_eol = 0;

    av_bprint_clear(buf);

    for (;;) {

        char c = ff_text_r8(tr);

        if (!c)

            break;

        /* ignore all initial line breaks */

        if (n == 0 && is_eol(c))

            continue;

        /* line break buffering: we don't want to add the trailing \r\n */

        if (is_eol(c)) {

            nb_eol += c == '\n' || last_was_cr;

            if (nb_eol == 2)

                break;

            eol_buf[i++] = c;

            if (i == sizeof(eol_buf) - 1)

                break;

            last_was_cr = c == '\r';

            continue;

        }

        /* only one line break followed by data: we flush the line breaks

         * buffer */

        if (i) {

            eol_buf[i] = 0;

            av_bprintf(buf, "%s", eol_buf);

            i = nb_eol = 0;

        }

        av_bprint_chars(buf, c, 1);

        n++;

    }

    return av_bprint_is_complete(buf) ? 0 : AVERROR(ENOMEM);

}

int ff_subtitles_read_chunk(AVIOContext *pb, AVBPrint *buf)

{

    FFTextReader tr;

    tr.buf_pos = tr.buf_len = 0;

    tr.type = 0;

    tr.pb = pb;

    return ff_subtitles_read_text_chunk(&tr, buf);

}

ptrdiff_t ff_subtitles_read_line(FFTextReader *tr, char *buf, size_t size)

{

    size_t cur = 0;

    if (!size)

        return 0;

    buf[0] = '\0';

    while (cur + 1 < size) {

        unsigned char c = ff_text_r8(tr);

        if (!c)

            return ff_text_eof(tr) ? cur : AVERROR_INVALIDDATA;

        if (c == '\r' || c == '\n')

            break;

        buf[cur++] = c;

        buf[cur] = '\0';

    }

    while (ff_text_peek_r8(tr) == '\r')

        ff_text_r8(tr);

    if (ff_text_peek_r8(tr) == '\n')

        ff_text_r8(tr);

    return cur;

}