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

 * scte18.c : SCTE-18 EAS decoder

 *****************************************************************************

 * Copyright (C) 2016 - VideoLAN Authors

 *

 * This program 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.

 *

 * This program 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 General Public License

 * along with this program.  If not, see <http://www.gnu.org/licenses/>.

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

#ifdef HAVE_CONFIG_H

# include "config.h"

#endif

#include <vlc_common.h>

#include <vlc_plugin.h>

#include <vlc_codec.h>

#include "atsc_a65.h"

#include "scte18.h"

#include "substext.h"

#include <time.h>

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

 * Module descriptor.

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

static int  Open (vlc_object_t *);

static void Close(vlc_object_t *);

vlc_module_begin ()

    set_description(N_("SCTE-18 decoder"))

    set_shortname(N_("SCTE-18"))

    set_capability( "spu decoder", 51)

    set_subcategory(SUBCAT_INPUT_SCODEC)

    set_callbacks(Open, Close)

vlc_module_end ()

typedef struct

{

    atsc_a65_handle_t *p_handle;

} decoder_sys_t;

//#define GPS_UTC_EPOCH_OFFSET 315964800

//#define GPS_CUR_UTC_LEAP_OFFSET  16 /* 1 Jul 2015 */

typedef struct scte18_cea_t

{

    uint16_t i_eas_event_id;

    char     rgc_eas_originator_code[3];

    char *   psz_eas_event_code;

    char *   psz_nature_of_activation;

    uint8_t  alert_message_time_remaining;

    uint32_t event_start_time;

    uint16_t event_duration;

    uint8_t  alert_priority;

    char *   psz_alert_text;

} scte18_cea_t;

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

 * Local prototypes

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

#define BUF_ADVANCE(n) p_buffer += n; i_buffer -= n;

static inline scte18_cea_t * scte18_cea_New(void)

{

    return calloc( 1, sizeof(scte18_cea_t) );

}

static void scte18_cea_Free( scte18_cea_t *p_cea )

{

    free( p_cea->psz_alert_text );

    free( p_cea->psz_nature_of_activation );

    free( p_cea->psz_eas_event_code );

    free( p_cea );

}

static scte18_cea_t * scte18_cea_Decode( atsc_a65_handle_t *p_handle, const block_t *p_block )

{

    size_t len;

    scte18_cea_t *p_cea = scte18_cea_New();

    if( !p_cea )

        return NULL;

    const uint8_t *p_buffer = p_block->p_buffer;

    size_t i_buffer = p_block->i_buffer;

    if( i_buffer < 34 || p_buffer[0] != 0 )

        goto error;

    BUF_ADVANCE(1);

    p_cea->i_eas_event_id = GetWBE( p_buffer );

    BUF_ADVANCE(2);

    memcpy( p_cea->rgc_eas_originator_code, p_buffer, 3 );

    BUF_ADVANCE(3);

    len = p_buffer[0];

    if( i_buffer < 23 + len )

        goto error;

    p_cea->psz_eas_event_code = malloc( len + 1 );

    memcpy( p_cea->psz_eas_event_code, &p_buffer[1], len );

    p_cea->psz_eas_event_code[len] = 0;

    BUF_ADVANCE( len + 1 );

    len = p_buffer[0];

    if( i_buffer < len + 22 )

        goto error;

    p_cea->psz_nature_of_activation = atsc_a65_Decode_multiple_string( p_handle, &p_buffer[1], len );

    BUF_ADVANCE(1 + len);

    if( i_buffer < 21 )

        goto error;

    p_cea->alert_message_time_remaining = p_buffer[0];

    BUF_ADVANCE(1);

    p_cea->event_start_time = GetDWBE( p_buffer );

    BUF_ADVANCE(4);

    p_cea->event_duration = GetWBE( p_buffer );

    if( p_cea->event_duration != 0 && ( p_cea->event_duration < 15 || p_cea->event_duration > 6000 ) )

        goto error;

    BUF_ADVANCE(2);

    p_cea->alert_priority = p_buffer[1] & 0x0f;

    switch( p_cea->alert_priority )

    {

        case EAS_PRIORITY_TEST:

        case EAS_PRIORITY_LOW:

        case EAS_PRIORITY_MEDIUM:

        case EAS_PRIORITY_HIGH:

        case EAS_PRIORITY_MAX:

            break;

        default:

            goto error;

    }

    BUF_ADVANCE(2);

    BUF_ADVANCE(2); //OOB_ID

    BUF_ADVANCE(2); //

    BUF_ADVANCE(2); //

    BUF_ADVANCE(2); //audio_OOB_ID

    len = GetWBE( p_buffer );

    if( i_buffer < len + 2 )

        goto error;

    p_cea->psz_alert_text = atsc_a65_Decode_multiple_string( p_handle, &p_buffer[2], len );

    return p_cea;

error:

    scte18_cea_Free( p_cea );

    return NULL;

}

static int Decode( decoder_t *p_dec, block_t *p_block )

{

    if ( p_block == NULL ) /* No Drain */

        return VLCDEC_SUCCESS;

    subpicture_t *p_spu = NULL;

    if (p_block->i_flags & (BLOCK_FLAG_CORRUPTED))

        goto exit;

    decoder_sys_t *p_sys = p_dec->p_sys;

    scte18_cea_t *p_cea = scte18_cea_Decode( p_sys->p_handle, p_block );

    if( p_cea )

    {

        p_spu = decoder_NewSubpictureText( p_dec );

        if( p_spu )

        {

            subtext_updater_sys_t *p_spu_sys = p_spu->updater.p_sys;

            p_spu->i_start = p_block->i_pts;

            if( p_cea->alert_message_time_remaining )

                p_spu->i_stop = p_spu->i_start + vlc_tick_from_sec( p_cea->alert_message_time_remaining );

            else

                p_spu->i_stop = VLC_TICK_INVALID;

            p_spu->b_ephemer  = true;

            p_spu->b_absolute = false;

            p_spu_sys->region.inner_align = SUBPICTURE_ALIGN_TOP;

            p_spu_sys->p_default_style->i_style_flags = STYLE_BOLD | STYLE_BACKGROUND;

            p_spu_sys->p_default_style->i_features |= STYLE_HAS_FLAGS;

            p_spu_sys->p_default_style->i_background_color = 0x000000;

            p_spu_sys->p_default_style->i_background_alpha = STYLE_ALPHA_OPAQUE;

            p_spu_sys->p_default_style->i_features |= STYLE_HAS_BACKGROUND_COLOR | STYLE_HAS_BACKGROUND_ALPHA;

            p_spu_sys->p_default_style->i_font_color = 0xFF0000;

            p_spu_sys->p_default_style->i_features |= STYLE_HAS_FONT_COLOR;

            p_spu_sys->region.p_segments = text_segment_New( p_cea->psz_alert_text );

            decoder_QueueSub( p_dec, p_spu );

        }

        msg_Info( p_dec, "Received %s", p_cea->psz_alert_text );

        scte18_cea_Free( p_cea );

    }

exit:

    block_Release( p_block );

    return VLCDEC_SUCCESS;

}

static int Open( vlc_object_t *object )

{

    decoder_t *dec = (decoder_t *)object;

    if ( dec->fmt_in->i_codec != VLC_CODEC_SCTE_18 )

        return VLC_EGENERIC;

    decoder_sys_t *p_sys = malloc( sizeof(decoder_sys_t) );

    if( unlikely(!p_sys) )

        return VLC_ENOMEM;

    p_sys->p_handle = atsc_a65_handle_New( NULL );

    if( !p_sys->p_handle )

    {

        free( p_sys );

        return VLC_EGENERIC;

    }

    dec->p_sys = p_sys;

    dec->pf_decode = Decode;

    dec->fmt_out.i_codec = 0;

    return VLC_SUCCESS;

}

static void Close( vlc_object_t *p_object )

{

    decoder_t *p_dec = (decoder_t *)p_object;

    decoder_sys_t *p_sys = (decoder_sys_t *) p_dec->p_sys;

    atsc_a65_handle_Release( p_sys->p_handle );

    free( p_sys );

}