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/*

 * Teletext decoding for ffmpeg

 * Copyright (c) 2005-2010, 2012 Wolfram Gloger

 * Copyright (c) 2013 Marton Balint

 *

 * This library 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 of the License, or (at your option) any later version.

 *

 * This library 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 this library; if not, write to the Free Software

 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

 */

#include "avcodec.h"

#include "libavutil/opt.h"

#include "libavutil/intreadwrite.h"

#include 

#define TEXT_MAXSZ    (25 * (56 + 1) * 4 + 2)

#define VBI_NB_COLORS 40

#define RGBA(r,g,b,a) (((a) << 24) | ((r) << 16) | ((g) << 8) | (b))

#define VBI_R(rgba)   (((rgba) >> 0) & 0xFF)

#define VBI_G(rgba)   (((rgba) >> 8) & 0xFF)

#define VBI_B(rgba)   (((rgba) >> 16) & 0xFF)

#define VBI_A(rgba)   (((rgba) >> 24) & 0xFF)

/* main data structure */

typedef struct TeletextContext

{

    AVClass        *class;

    char           *pgno;

    int             x_offset;

    int             y_offset;

    char           *format;

    int             format_id; /* 0 = bitmap, 1 = text */

    int             chop_top;

    int             sub_duration; /* in msec */

    int             transparent_bg;

    int             chop_spaces;

    int             lines_processed;

    AVSubtitleRect *sub_rect;

    vbi_decoder *   vbi;

    vbi_dvb_demux * dx;

#ifdef DEBUG

    vbi_export *    ex;

#endif

    /* Don't even _think_ about making sliced stack-local! */

    vbi_sliced      sliced[64];

} TeletextContext;

/************************************************************************/

static int

chop_spaces_utf8(const unsigned char* t, int len)

{

    t += len;

    while (len > 0) {

        if (*--t != ' ' || (len-1 > 0 && *(t-1) & 0x80))

            break;

        --len;

    }

    return len;

}

// draw a page as text

static int

gen_sub_text(TeletextContext *ctx, vbi_page *page, int chop_top)

{

    AVSubtitleRect *sub_rect = ctx->sub_rect;

    char *text;

    const char *in;

    char *out;

    char *vbi_text = av_malloc(TEXT_MAXSZ);

    int sz;

    if (!vbi_text)

        return AVERROR(ENOMEM);

    sz = vbi_print_page_region(page, vbi_text, TEXT_MAXSZ-1, "UTF-8",

                                   /*table mode*/ TRUE, FALSE,

                                   0,             chop_top,

                                   page->columns, page->rows-chop_top);

    if (sz <= 0) {

        av_log(ctx, AV_LOG_ERROR, "vbi_print error\n");

        av_free(vbi_text);

        return AVERROR_EXTERNAL;

    }

    vbi_text[sz] = '\0';

    in  = vbi_text;

    out = text = av_malloc(TEXT_MAXSZ);

    if (!text) {

        av_free(vbi_text);

        return AVERROR(ENOMEM);

    }

    if (ctx->chop_spaces) {

        for (;;) {

            int nl, sz;

            // skip leading spaces and newlines

            in += strspn(in, " \n");

            // compute end of row

            for (nl = 0; in[nl]; ++nl)

                if (in[nl] == '\n' && (nl==0 || !(in[nl-1] & 0x80)))

                    break;

            if (!in[nl])

                break;

            // skip trailing spaces

            sz = chop_spaces_utf8(in, nl);

            memcpy(out, in, sz);

            out += sz;

            *out++ = '\n';

            in += nl;

        }

    } else {

        strcpy(text, vbi_text);

        out += sz;

        *out++ = '\n';

    }

    av_free(vbi_text);

    *out = '\0';

    if (out > text) {

        sub_rect->type = SUBTITLE_TEXT;

        sub_rect->text = text;

        av_log(ctx, AV_LOG_DEBUG, "subtext:%s:txetbus\n", text);

    } else {

        sub_rect->type = SUBTITLE_NONE;

        av_free(text);

    }

    return 0;

}

static void

fix_transparency(TeletextContext *ctx, vbi_page *page, int chop_top, uint8_t transparent_color, int resx, int resy)

{

    AVSubtitleRect *sub_rect = ctx->sub_rect;

    int iy;

    // Hack for transparency, inspired by VLC code...

    for (iy = 0; iy < resy; iy++) {

        uint8_t *pixel = sub_rect->pict.data[0] + iy * sub_rect->pict.linesize[0];

        vbi_char *vc = page->text + (iy / 10 + chop_top) * page->columns;

        vbi_char *vcnext = vc + page->columns;

        for (; vc < vcnext; vc++) {

            uint8_t *pixelnext = pixel + 12;

            switch (vc->opacity) {

                case VBI_TRANSPARENT_SPACE:

                    memset(pixel, transparent_color, 12);

                    break;

                case VBI_OPAQUE:

                case VBI_SEMI_TRANSPARENT:

                    if (!ctx->transparent_bg)

                        break;

                case VBI_TRANSPARENT_FULL:

                    for(; pixel < pixelnext; pixel++)

                        if (*pixel == vc->background)

                            *pixel = transparent_color;

                    break;

            }

            pixel = pixelnext;

        }

    }

}

// draw a page as bitmap

static int

gen_sub_bitmap(TeletextContext *ctx, vbi_page *page, int chop_top)

{

    AVSubtitleRect *sub_rect = ctx->sub_rect;

    int resx = page->columns * 12;

    int resy = (page->rows - chop_top) * 10;

    uint8_t ci, cmax = 0;

    int ret;

    vbi_char *vc = page->text + (chop_top * page->columns);

    vbi_char *vcend = page->text + (page->rows * page->columns);

    for (; vc < vcend; vc++) {

        if (vc->opacity != VBI_TRANSPARENT_SPACE) {

            cmax = VBI_NB_COLORS;

            break;

        }

    }

    if (cmax == 0) {

        av_log(ctx, AV_LOG_DEBUG, "dropping empty page %3x\n", page->pgno);

        sub_rect->type = SUBTITLE_NONE;

        return 0;

    }

    if ((ret = avpicture_alloc(&sub_rect->pict, AV_PIX_FMT_PAL8, resx, resy)) < 0)

        return ret;

    // Yes, we want to allocate the palette on our own because AVSubtitle works this way

    sub_rect->pict.data[1] = NULL;

    vbi_draw_vt_page_region(page, VBI_PIXFMT_PAL8,

                            sub_rect->pict.data[0], sub_rect->pict.linesize[0],

                            0, chop_top, page->columns, page->rows - chop_top,

                            /*reveal*/ 1, /*flash*/ 1);

    fix_transparency(ctx, page, chop_top, cmax, resx, resy);

    sub_rect->x = ctx->x_offset;

    sub_rect->y = ctx->y_offset;

    sub_rect->w = resx;

    sub_rect->h = resy;

    sub_rect->nb_colors = (int)cmax + 1;

    sub_rect->pict.data[1] = av_mallocz(AVPALETTE_SIZE);

    if (!sub_rect->pict.data[1]) {

        av_freep(&sub_rect->pict.data[0]);

        return AVERROR(ENOMEM);

    }

    for (ci = 0; ci < cmax; ci++) {

        int r, g, b, a;

        r = VBI_R(page->color_map[ci]);

        g = VBI_G(page->color_map[ci]);

        b = VBI_B(page->color_map[ci]);

        a = VBI_A(page->color_map[ci]);

        ((uint32_t *)sub_rect->pict.data[1])[ci] = RGBA(r, g, b, a);

#ifdef DEBUG

        av_log(ctx, AV_LOG_DEBUG, "palette %0x\n",

               ((uint32_t *)sub_rect->pict.data[1])[ci]);

#endif

    }

    ((uint32_t *)sub_rect->pict.data[1])[cmax] = RGBA(0, 0, 0, 0);

    sub_rect->type = SUBTITLE_BITMAP;

    return 0;

}

static void

handler(vbi_event *ev, void *user_data)

{

    TeletextContext *ctx = user_data;

    vbi_page page;

    int res;

    char pgno_str[12];

    vbi_subno subno;

    vbi_page_type vpt;

    int chop_top;

    char *lang;

    snprintf(pgno_str, sizeof pgno_str, "%03x", ev->ev.ttx_page.pgno);

    av_log(ctx, AV_LOG_DEBUG, "decoded page %s.%02x\n",

           pgno_str, ev->ev.ttx_page.subno & 0xFF);

    if (strcmp(ctx->pgno, "*") && !strstr(ctx->pgno, pgno_str))

        return;

    /* Fetch the page.  */

    res = vbi_fetch_vt_page(ctx->vbi, &page,

                            ev->ev.ttx_page.pgno,

                            ev->ev.ttx_page.subno,

                            VBI_WST_LEVEL_3p5, 25, TRUE);

    if (!res)

        return;

#ifdef DEBUG

    fprintf(stderr, "\nSaving res=%d dy0=%d dy1=%d...\n",

            res, page.dirty.y0, page.dirty.y1);

    fflush(stderr);

    if (!vbi_export_stdio(ctx->ex, stderr, &page))

        fprintf(stderr, "failed: %s\n", vbi_export_errstr(ctx->ex));

#endif

    vpt = vbi_classify_page(ctx->vbi, ev->ev.ttx_page.pgno, &subno, &lang);

    chop_top = ctx->chop_top ||

        ((page.rows > 1) && (vpt == VBI_SUBTITLE_PAGE));

    av_log(ctx, AV_LOG_DEBUG, "%d x %d page chop:%d\n",

           page.columns, page.rows, chop_top);

    if (!ctx->sub_rect) {

        ctx->sub_rect = av_mallocz(sizeof(*ctx->sub_rect));

        if (ctx->sub_rect) {

            res = (ctx->format_id == 0) ?

                gen_sub_bitmap(ctx, &page, chop_top) :

                gen_sub_text  (ctx, &page, chop_top);

            if (res)

                av_freep(&ctx->sub_rect);

        }

    } else {

        // FIXME: Multiple teletext pages in a single packet, some kind of buffering should be done instead of dropping the page...

        av_log(ctx, AV_LOG_WARNING, "Missed page %s.%02x.\n", pgno_str, ev->ev.ttx_page.subno & 0xFF);

    }

    vbi_unref_page(&page);

}

static int

teletext_decode_frame(AVCodecContext *avctx,

                      void *data, int *data_size,

                      AVPacket *pkt)

{

    TeletextContext *ctx = avctx->priv_data;

    AVSubtitle      *sub = data;

    const uint8_t   *buf = pkt->data;

    unsigned int    left = pkt->size;

    uint8_t         pesheader[45] = {0x00, 0x00, 0x01, 0xbd, 0x00, 0x00, 0x85, 0x80, 0x24, 0x21, 0x00, 0x01, 0x00, 0x01};

    int             pesheader_size = sizeof(pesheader);

    const uint8_t   *pesheader_buf = pesheader;

    if (!ctx->vbi) {

        if (!(ctx->vbi = vbi_decoder_new()))

            return AVERROR(ENOMEM);

        if (!vbi_event_handler_add(ctx->vbi, VBI_EVENT_TTX_PAGE, handler, ctx)) {

            vbi_decoder_delete(ctx->vbi);

            ctx->vbi = NULL;

            return AVERROR(ENOMEM);

        }

    }

    if (!ctx->dx && (!(ctx->dx = vbi_dvb_pes_demux_new (/* callback */ NULL, NULL))))

        return AVERROR(ENOMEM);

    // We allow unreasonably big packets, even if the standard only allows a max size of 1472

    if ((pesheader_size + left) < 184 || (pesheader_size + left) > 65504 || (pesheader_size + left) % 184 != 0)

        return AVERROR_INVALIDDATA;

    memset(pesheader + 14, 0xff, pesheader_size - 14);

    AV_WB16(pesheader + 4, left + pesheader_size - 6);

    /* PTS is deliberately left as 0 in the PES header, otherwise libzvbi uses

     * it to detect dropped frames. Unforunatey the guessed packet PTS values

     * (see mpegts demuxer) are not accurate enough to pass that test. */

    vbi_dvb_demux_cor(ctx->dx, ctx->sliced, 64, NULL, &pesheader_buf, &pesheader_size);

    while (left > 0) {

        int64_t pts = 0;

        unsigned int lines = vbi_dvb_demux_cor(ctx->dx, ctx->sliced, 64, &pts, &buf, &left);

#ifdef DEBUG

        av_log(avctx, AV_LOG_DEBUG,

               "ctx=%p buf_size=%d left=%u lines=%u pts=%f pkt_pts=%f\n",

               ctx, pkt->size, left, lines, (double)pts/90000.0, (double)pkt->pts/90000.0);

#endif

        if (lines > 0) {

#ifdef DEBUGx

            int i;

            for(i=0; i

                av_log(avctx, AV_LOG_DEBUG,

                       "lines=%d id=%x\n", i, ctx->sliced[i].id);

#endif

            vbi_decode(ctx->vbi, ctx->sliced, lines, (double)pts/90000.0);

            ctx->lines_processed += lines;

        }

    }

    // is there a subtitle to pass?

    if (ctx->sub_rect) {

        sub->format = (ctx->sub_rect->type == SUBTITLE_TEXT ? 1: 0);

        sub->start_display_time = 0;

        sub->end_display_time = ctx->sub_duration;

        sub->num_rects = 0;

        if (ctx->sub_rect->type != SUBTITLE_NONE) {

            sub->rects = av_malloc(sizeof(*sub->rects) * 1);

            if (sub->rects) {

                sub->num_rects = 1;

                sub->rects[0] = ctx->sub_rect;

            }

        } else {

            av_log(avctx, AV_LOG_DEBUG, "sending empty sub\n");

            sub->rects = NULL;

        }

        if (!sub->rects) // no rect was passed

            av_free(ctx->sub_rect);

        ctx->sub_rect = NULL;

        *data_size = 1;

    } else

        *data_size = 0;

    return pkt->size;

}

static int teletext_init_decoder(AVCodecContext *avctx)

{

    TeletextContext *ctx = avctx->priv_data;

    unsigned int maj, min, rev;

    vbi_version(&maj, &min, &rev);

    if (!(maj > 0 || min > 2 || min == 2 && rev >= 26)) {

        av_log(avctx, AV_LOG_ERROR, "decoder needs zvbi version >= 0.2.26.\n");

        return AVERROR_EXTERNAL;

    }

    ctx->dx = NULL;

    ctx->vbi = NULL;

    ctx->sub_rect = NULL;

    if (!strcmp(ctx->format, "bitmap")) {

        ctx->format_id = 0;

    } else if (!strcmp(ctx->format, "text")) {

        ctx->format_id = 1;

    } else {

        av_log(avctx, AV_LOG_ERROR, "unkown format %s\n", ctx->format);

        return AVERROR_OPTION_NOT_FOUND;

    }

#ifdef DEBUG

    {

        char *t;

        ctx->ex = vbi_export_new("text", &t);

    }

#endif

    av_log(avctx, AV_LOG_VERBOSE, "page filter: %s\n", ctx->pgno);

    return 0;

}

static int teletext_close_decoder(AVCodecContext *avctx)

{

    TeletextContext *ctx = avctx->priv_data;

#ifdef DEBUG

    av_log(avctx, AV_LOG_DEBUG, "lines_total=%u\n", ctx->lines_processed);

#endif

    vbi_dvb_demux_delete(ctx->dx);

    vbi_decoder_delete(ctx->vbi);

    ctx->dx = NULL;

    ctx->vbi = NULL;

    return 0;

}

static void teletext_flush(AVCodecContext *avctx)

{

    teletext_close_decoder(avctx);

}

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

#define SD AV_OPT_FLAG_SUBTITLE_PARAM | AV_OPT_FLAG_DECODING_PARAM

static const AVOption options[] = {

    {"txt_page",        "list of teletext page numbers to decode, * is all", OFFSET(pgno),           AV_OPT_TYPE_STRING, {.str = "*"},      0, 0,        SD},

    {"txt_chop_top",    "discards the top teletext line",                    OFFSET(chop_top),       AV_OPT_TYPE_INT,    {.i64 = 1},        0, 1,        SD},

    {"txt_format",      "format of the subtitles (bitmap or text)",          OFFSET(format),         AV_OPT_TYPE_STRING, {.str = "bitmap"}, 0, 0,        SD},

    {"txt_left",        "x offset of generated bitmaps",                     OFFSET(x_offset),       AV_OPT_TYPE_INT,    {.i64 = 0},        0, 65535,    SD},

    {"txt_top",         "y offset of generated bitmaps",                     OFFSET(y_offset),       AV_OPT_TYPE_INT,    {.i64 = 0},        0, 65535,    SD},

    {"txt_chop_spaces", "chops leading and trailing spaces from text",       OFFSET(chop_spaces),    AV_OPT_TYPE_INT,    {.i64 = 1},        0, 1,        SD},

    {"txt_duration",    "display duration of teletext pages in msecs",       OFFSET(sub_duration),   AV_OPT_TYPE_INT,    {.i64 = 30000},    0, 86400000, SD},

    {"txt_transparent", "force transparent background of the teletext",      OFFSET(transparent_bg), AV_OPT_TYPE_INT,    {.i64 = 0},        0, 1,        SD},

    { NULL },

};

static const AVClass teletext_class = {

    .class_name = "libzvbi_teletextdec",

    .item_name  = av_default_item_name,

    .option     = options,

    .version    = LIBAVUTIL_VERSION_INT,

};

AVCodec ff_libzvbi_teletext_decoder = {

    .name      = "libzvbi_teletextdec",

    .long_name = NULL_IF_CONFIG_SMALL("Libzvbi DVB teletext decoder"),

    .type      = AVMEDIA_TYPE_SUBTITLE,

    .id        = CODEC_ID_DVB_TELETEXT,

    .priv_data_size = sizeof(TeletextContext),

    .init      = teletext_init_decoder,

    .close     = teletext_close_decoder,

    .decode    = teletext_decode_frame,

    .flush     = teletext_flush,

    .priv_class= &teletext_class,

};