/*

 * SubRip subtitle encoder

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

 *

 * 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 "config_components.h"

#include <stdarg.h>

#include "avcodec.h"

#include "libavutil/bprint.h"

#include "ass_split.h"

#include "ass.h"

#include "codec_internal.h"

#define SRT_STACK_SIZE 64

typedef struct {

    AVCodecContext *avctx;

    ASSSplitContext *ass_ctx;

    AVBPrint buffer;

    char stack[SRT_STACK_SIZE];

    int stack_ptr;

    int alignment_applied;

} SRTContext;

static av_printf_format(2, 3) void srt_print(SRTContext *s, const char *str, ...)

{

    va_list vargs;

    va_start(vargs, str);

    av_vbprintf(&s->buffer, str, vargs);

    va_end(vargs);

}

static int srt_stack_push(SRTContext *s, const char c)

{

    if (s->stack_ptr >= SRT_STACK_SIZE)

        return -1;

    s->stack[s->stack_ptr++] = c;

    return 0;

}

static char srt_stack_pop(SRTContext *s)

{

    if (s->stack_ptr <= 0)

        return 0;

    return s->stack[--s->stack_ptr];

}

static int srt_stack_find(SRTContext *s, const char c)

{

    int i;

    for (i = s->stack_ptr-1; i >= 0; i--)

        if (s->stack[i] == c)

            break;

    return i;

}

static void srt_close_tag(SRTContext *s, char tag)

{

    srt_print(s, "</%c%s>", tag, tag == 'f' ? "ont" : "");

}

static void srt_stack_push_pop(SRTContext *s, const char c, int close)

{

    if (close) {

        int i = c ? srt_stack_find(s, c) : 0;

        if (i < 0)

            return;

        while (s->stack_ptr != i)

            srt_close_tag(s, srt_stack_pop(s));

    } else if (srt_stack_push(s, c) < 0)

        av_log(s->avctx, AV_LOG_ERROR, "tag stack overflow\n");

}

static void srt_style_apply(SRTContext *s, const char *style)

{

    ASSStyle *st = ff_ass_style_get(s->ass_ctx, style);

    if (st) {

        int c = st->primary_color & 0xFFFFFF;

        if (st->font_name && strcmp(st->font_name, ASS_DEFAULT_FONT) ||

            st->font_size != ASS_DEFAULT_FONT_SIZE ||

            c != ASS_DEFAULT_COLOR) {

            srt_print(s, "<font");

            if (st->font_name && strcmp(st->font_name, ASS_DEFAULT_FONT))

                srt_print(s, " face=\"%s\"", st->font_name);

            if (st->font_size != ASS_DEFAULT_FONT_SIZE)

                srt_print(s, " size=\"%d\"", st->font_size);

            if (c != ASS_DEFAULT_COLOR)

                srt_print(s, " color=\"#%06x\"",

                          (c & 0xFF0000) >> 16 | c & 0xFF00 | (c & 0xFF) << 16);

            srt_print(s, ">");

            srt_stack_push(s, 'f');

        }

        if (st->bold != ASS_DEFAULT_BOLD) {

            srt_print(s, "<b>");

            srt_stack_push(s, 'b');

        }

        if (st->italic != ASS_DEFAULT_ITALIC) {

            srt_print(s, "<i>");

            srt_stack_push(s, 'i');

        }

        if (st->underline != ASS_DEFAULT_UNDERLINE) {

            srt_print(s, "<u>");

            srt_stack_push(s, 'u');

        }

        if (st->alignment != ASS_DEFAULT_ALIGNMENT) {

            srt_print(s, "{\\an%d}", st->alignment);

            s->alignment_applied = 1;

        }

    }

}

static av_cold int srt_encode_init(AVCodecContext *avctx)

{

    SRTContext *s = avctx->priv_data;

    s->avctx = avctx;

    s->ass_ctx = ff_ass_split(avctx->subtitle_header);

    return s->ass_ctx ? 0 : AVERROR_INVALIDDATA;

}

static void srt_text_cb(void *priv, const char *text, int len)

{

    SRTContext *s = priv;

    av_bprint_append_data(&s->buffer, text, len);

}

static void srt_new_line_cb(void *priv, int forced)

{

    srt_print(priv, "\n");

}

static void srt_style_cb(void *priv, char style, int close)

{

    srt_stack_push_pop(priv, style, close);

    if (!close)

        srt_print(priv, "<%c>", style);

}

static void srt_color_cb(void *priv, unsigned int color, unsigned int color_id)

{

    if (color_id > 1)

        return;

    srt_stack_push_pop(priv, 'f', color == 0xFFFFFFFF);

    if (color != 0xFFFFFFFF)

        srt_print(priv, "<font color=\"#%06x\">",

              (color & 0xFF0000) >> 16 | color & 0xFF00 | (color & 0xFF) << 16);

}

static void srt_font_name_cb(void *priv, const char *name)

{

    srt_stack_push_pop(priv, 'f', !name);

    if (name)

        srt_print(priv, "<font face=\"%s\">", name);

}

static void srt_font_size_cb(void *priv, int size)

{

    srt_stack_push_pop(priv, 'f', size < 0);

    if (size >= 0)

        srt_print(priv, "<font size=\"%d\">", size);

}

static void srt_alignment_cb(void *priv, int alignment)

{

    SRTContext *s = priv;

    if (!s->alignment_applied && alignment >= 0) {

        srt_print(s, "{\\an%d}", alignment);

        s->alignment_applied = 1;

    }

}

static void srt_cancel_overrides_cb(void *priv, const char *style)

{

    srt_stack_push_pop(priv, 0, 1);

    srt_style_apply(priv, style);

}

static void srt_move_cb(void *priv, int x1, int y1, int x2, int y2,

                        int t1, int t2)

{

    // TODO: add a AV_PKT_DATA_SUBTITLE_POSITION side data when a new subtitles

    // encoding API passing the AVPacket is available.

}

static void srt_end_cb(void *priv)

{

    srt_stack_push_pop(priv, 0, 1);

}

static const ASSCodesCallbacks srt_callbacks = {

    .text             = srt_text_cb,

    .new_line         = srt_new_line_cb,

    .style            = srt_style_cb,

    .color            = srt_color_cb,

    .font_name        = srt_font_name_cb,

    .font_size        = srt_font_size_cb,

    .alignment        = srt_alignment_cb,

    .cancel_overrides = srt_cancel_overrides_cb,

    .move             = srt_move_cb,

    .end              = srt_end_cb,

};

static const ASSCodesCallbacks text_callbacks = {

    .text             = srt_text_cb,

    .new_line         = srt_new_line_cb,

};

static int encode_frame(AVCodecContext *avctx,

                        unsigned char *buf, int bufsize, const AVSubtitle *sub,

                        const ASSCodesCallbacks *cb)

{

    SRTContext *s = avctx->priv_data;

    ASSDialog *dialog;

    int i;

    av_bprint_init_for_buffer(&s->buffer, buf, bufsize);

    for (i=0; i<sub->num_rects; i++) {

        const char *ass = sub->rects[i]->ass;

        if (sub->rects[i]->type != SUBTITLE_ASS) {

            av_log(avctx, AV_LOG_ERROR, "Only SUBTITLE_ASS type supported.\n");

            return AVERROR(EINVAL);

        }

        dialog = ff_ass_split_dialog(s->ass_ctx, ass);

        if (!dialog)

            return AVERROR(ENOMEM);

        s->alignment_applied = 0;

        if (avctx->codec_id == AV_CODEC_ID_SUBRIP)

            srt_style_apply(s, dialog->style);

        ff_ass_split_override_codes(cb, s, dialog->text);

        ff_ass_free_dialog(&dialog);

    }

    if (!s->buffer.len)

        return 0;

    if (!av_bprint_is_complete(&s->buffer)) {

        av_log(avctx, AV_LOG_ERROR, "Buffer too small for ASS event.\n");

        return AVERROR_BUFFER_TOO_SMALL;

    }

    return s->buffer.len;

}

static int srt_encode_frame(AVCodecContext *avctx,

                               unsigned char *buf, int bufsize, const AVSubtitle *sub)

{

    return encode_frame(avctx, buf, bufsize, sub, &srt_callbacks);

}

static int text_encode_frame(AVCodecContext *avctx,

                             unsigned char *buf, int bufsize, const AVSubtitle *sub)

{

    return encode_frame(avctx, buf, bufsize, sub, &text_callbacks);

}

static av_cold int srt_encode_close(AVCodecContext *avctx)

{

    SRTContext *s = avctx->priv_data;

    ff_ass_split_free(s->ass_ctx);

    return 0;

}

#if CONFIG_SRT_ENCODER

/* deprecated encoder */

const FFCodec ff_srt_encoder = {

    .p.name         = "srt",

    CODEC_LONG_NAME("SubRip subtitle"),

    .p.type         = AVMEDIA_TYPE_SUBTITLE,

    .p.id           = AV_CODEC_ID_SUBRIP,

    .priv_data_size = sizeof(SRTContext),

    .init           = srt_encode_init,

    FF_CODEC_ENCODE_SUB_CB(srt_encode_frame),

    .close          = srt_encode_close,

};

#endif

#if CONFIG_SUBRIP_ENCODER

const FFCodec ff_subrip_encoder = {

    .p.name         = "subrip",

    CODEC_LONG_NAME("SubRip subtitle"),

    .p.type         = AVMEDIA_TYPE_SUBTITLE,

    .p.id           = AV_CODEC_ID_SUBRIP,

    .priv_data_size = sizeof(SRTContext),

    .init           = srt_encode_init,

    FF_CODEC_ENCODE_SUB_CB(srt_encode_frame),

    .close          = srt_encode_close,

};

#endif

#if CONFIG_TEXT_ENCODER

const FFCodec ff_text_encoder = {

    .p.name         = "text",

    CODEC_LONG_NAME("Raw text subtitle"),

    .p.type         = AVMEDIA_TYPE_SUBTITLE,

    .p.id           = AV_CODEC_ID_TEXT,

    .priv_data_size = sizeof(SRTContext),

    .init           = srt_encode_init,

    FF_CODEC_ENCODE_SUB_CB(text_encode_frame),

    .close          = srt_encode_close,

};

#endif