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

 * oggspots.c: OggSpots decoder module.

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

 * Copyright (C) 2016 VLC authors and VideoLAN

 *

 * Authors: Michael Taenzer <neo@nhng.de>

 *

 * 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 Lesser General Public License

 * along with this program; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.

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

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

 * Preamble

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

#ifdef HAVE_CONFIG_H

# include "config.h"

#endif

#include <vlc_common.h>

#include <vlc_plugin.h>

#include <vlc_codec.h>

#include <vlc_image.h>

#include <assert.h>

#include <limits.h>

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

 * decoder_sys_t : oggspots decoder descriptor

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

typedef struct

{

    /* Module mode */

    bool b_packetizer;

    /*

     * Input properties

     */

    bool b_has_headers;

    /*

     * Image handler

     */

    image_handler_t* p_image;

    /*

     * Common properties

     */

    vlc_tick_t i_pts;

} decoder_sys_t;

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

 * Local prototypes

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

static int  OpenDecoder   (vlc_object_t*);

static int  OpenPacketizer(vlc_object_t*);

static void CloseDecoder  (vlc_object_t*);

static int        DecodeVideo  (decoder_t*, block_t*);

static block_t*   Packetize  (decoder_t*, block_t**);

static int        ProcessHeader(decoder_t*);

static void*      ProcessPacket(decoder_t*, block_t*);

static void       Flush        (decoder_t*);

static picture_t* DecodePacket (decoder_t*, block_t*);

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

 * Module descriptor

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

vlc_module_begin ()

    set_subcategory(SUBCAT_INPUT_VCODEC)

    set_shortname("OggSpots")

    set_description(N_("OggSpots video decoder"))

    set_capability("video decoder", 10)

    set_callbacks(OpenDecoder, CloseDecoder)

    add_shortcut("oggspots")

    add_submodule ()

    set_description(N_("OggSpots video packetizer"))

    set_capability("video packetizer", 10)

    set_callbacks(OpenPacketizer, CloseDecoder)

    add_shortcut("oggspots")

vlc_module_end ()

static int OpenCommon(vlc_object_t* p_this, bool b_packetizer)

{

    decoder_t* p_dec = (decoder_t*)p_this;

    decoder_sys_t* p_sys;

    if (p_dec->fmt_in->i_codec != VLC_CODEC_OGGSPOTS) {

        return VLC_EGENERIC;

    }

    /* Allocate the memory needed to store the decoder's structure */

    p_sys = malloc(sizeof(*p_sys));

    if (p_sys == NULL) {

        return VLC_ENOMEM;

    }

    p_dec->p_sys = p_sys;

    p_sys->b_packetizer = b_packetizer;

    p_sys->b_has_headers = false;

    p_sys->i_pts = VLC_TICK_INVALID;

    /* Initialize image handler */

    p_sys->p_image = image_HandlerCreate(p_dec);

    if (p_sys->p_image == NULL) {

        free(p_sys);

        return VLC_ENOMEM;

    }

    if( b_packetizer )

    {

        p_dec->fmt_out.i_codec = VLC_CODEC_OGGSPOTS;

        p_dec->pf_packetize = Packetize;

    }

    else

    {

        p_dec->fmt_out.i_codec = VLC_CODEC_RGBA;

        p_dec->pf_decode = DecodeVideo;

    }

    p_dec->pf_flush = Flush;

    return VLC_SUCCESS;

}

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

 * OpenDecoder: probe the decoder and return score

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

static int OpenDecoder(vlc_object_t* p_this)

{

    return OpenCommon(p_this, false);

}

static int OpenPacketizer(vlc_object_t* p_this)

{

    return OpenCommon(p_this, true);

}

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

 * DecodeBlock: the whole thing

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

 * This function must be fed with ogg packets.

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

static void* DecodeBlock(decoder_t* p_dec, block_t* p_block)

{

    decoder_sys_t* p_sys = p_dec->p_sys;

    /* Check for headers */

    if (!p_sys->b_has_headers) {

        if (ProcessHeader(p_dec)) {

            block_Release(p_block);

            return NULL;

        }

        p_sys->b_has_headers = true;

    }

    return ProcessPacket(p_dec, p_block);

}

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

{

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

        return VLCDEC_SUCCESS;

    picture_t *p_pic = DecodeBlock( p_dec, p_block );

    if( p_pic != NULL )

        decoder_QueueVideo( p_dec, p_pic );

    return VLCDEC_SUCCESS;

}

static block_t *Packetize( decoder_t *p_dec, block_t **pp_block )

{

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

        return NULL;

    block_t *p_block = *pp_block; *pp_block = NULL;

    if( p_block == NULL )

        return NULL;

    return DecodeBlock( p_dec, p_block );

}

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

 * ProcessHeader: process OggSpots header.

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

static int ProcessHeader(decoder_t* p_dec)

{

    decoder_sys_t* p_sys = p_dec->p_sys;

    const uint8_t* p_extra;

    int i_major;

    int i_minor;

    uint64_t i_granulerate_numerator;

    uint64_t i_granulerate_denominator;

    /* The OggSpots header is always 52 bytes */

    if (p_dec->fmt_in->i_extra != 52) {

        return VLC_EGENERIC;

    }

    p_extra = p_dec->fmt_in->p_extra;

    /* Identification string */

    if ( memcmp(p_extra, "SPOTS\0\0", 8) ) {

        return VLC_EGENERIC;

    }

    /* Version number */

    i_major = GetWLE(&p_extra[ 8]); /* major version num */

    i_minor = GetWLE(&p_extra[10]); /* minor version num */

    if (i_major != 0 || i_minor != 1) {

        return VLC_EGENERIC;

    }

    /* Granule rate */

    i_granulerate_numerator   = GetQWLE(&p_extra[12]);

    i_granulerate_denominator = GetQWLE(&p_extra[20]);

    if (i_granulerate_numerator == 0 || i_granulerate_denominator == 0) {

        return VLC_EGENERIC;

    }

    /* The OggSpots spec contained an error and there are implementations out

     * there that used the wrong value. So we detect that case and switch

     * numerator and denominator in that case */

    if (i_granulerate_numerator == 1 && i_granulerate_denominator == 30) {

        i_granulerate_numerator   = 30;

        i_granulerate_denominator = 1;

    }

    /* Normalize granulerate */

    vlc_ureduce(&p_dec->fmt_out.video.i_frame_rate,

                &p_dec->fmt_out.video.i_frame_rate_base,

                i_granulerate_numerator, i_granulerate_denominator, 0);

    /* Image format */

    if (!p_sys->b_packetizer) {

        if ( memcmp(&p_extra[32], "PNG", 3) && memcmp(&p_extra[32], "JPEG", 4) ) {

            char psz_image_type[8+1];

            strncpy(psz_image_type, (char*)&p_extra[32], 8);

            psz_image_type[sizeof(psz_image_type)-1] = '\0';

            msg_Warn(p_dec, "Unsupported image format: %s", psz_image_type);

        }

    }

    /* Dimensions */

    p_dec->fmt_out.video.i_width  = p_dec->fmt_out.video.i_visible_width  =

            GetWLE(&p_extra[40]);

    p_dec->fmt_out.video.i_height = p_dec->fmt_out.video.i_visible_height =

            GetWLE(&p_extra[42]);

    /* We assume square pixels */

    p_dec->fmt_out.video.i_sar_num = 1;

    p_dec->fmt_out.video.i_sar_den = 1;

    /* We don't implement background color, alignment and options at the

     * moment because the former doesn't seem necessary right now and the

     * latter are underspecified. */

    if (p_sys->b_packetizer) {

        void* p_new_extra = realloc(p_dec->fmt_out.p_extra,

                                p_dec->fmt_in->i_extra);

        if (unlikely(p_new_extra == NULL)) {

            return VLC_ENOMEM;

        }

        p_dec->fmt_out.p_extra = p_new_extra;

        p_dec->fmt_out.i_extra = p_dec->fmt_in->i_extra;

        memcpy(p_dec->fmt_out.p_extra,

               p_dec->fmt_in->p_extra, p_dec->fmt_out.i_extra);

    }

    return VLC_SUCCESS;

}

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

 * Flush:

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

static void Flush(decoder_t* p_dec)

{

    decoder_sys_t* p_sys = p_dec->p_sys;

    p_sys->i_pts = VLC_TICK_INVALID;

}

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

 * ProcessPacket: processes an OggSpots packet.

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

static void* ProcessPacket(decoder_t* p_dec, block_t* p_block)

{

    decoder_sys_t* p_sys = p_dec->p_sys;

    void* p_buf;

    if ( (p_block->i_flags & BLOCK_FLAG_DISCONTINUITY) != 0 ) {

        p_sys->i_pts = p_block->i_pts;

    }

    if ( (p_block->i_flags & BLOCK_FLAG_CORRUPTED) != 0 ) {

        block_Release(p_block);

        return NULL;

    }

    /* Date management */

    if (p_block->i_pts != VLC_TICK_INVALID && p_block->i_pts != p_sys->i_pts) {

        p_sys->i_pts = p_block->i_pts;

    }

    if (p_sys->b_packetizer) {

        /* Date management */

        /* FIXME: This is copied from theora but it looks wrong.

         * p_block->i_length will always be zero. */

        p_block->i_dts = p_block->i_pts = p_sys->i_pts;

        p_block->i_length = p_sys->i_pts - p_block->i_pts;

        p_buf = p_block;

    }

    else {

        p_buf = DecodePacket(p_dec, p_block);

    }

    return p_buf;

}

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

 * DecodePacket: decodes an OggSpots packet.

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

static picture_t* DecodePacket(decoder_t* p_dec, block_t* p_block)

{

    decoder_sys_t* p_sys = p_dec->p_sys;

    uint32_t i_img_offset;

    picture_t* p_pic;

    if (p_block->i_buffer < 20) {

        msg_Dbg(p_dec, "Packet too short");

        goto error;

    }

    /* Byte offset */

    i_img_offset = GetDWLE(p_block->p_buffer);

    if (i_img_offset < 20) {

        msg_Dbg(p_dec, "Invalid byte offset");

        goto error;

    }

    if (i_img_offset > p_block->i_buffer) {

        msg_Dbg(p_dec, "Invalid byte offset: %u exceeds packet size %zu",

                i_img_offset, p_block->i_buffer);

        goto error;

    }

    /* Image format */

    es_format_t fmt_in = *p_dec->fmt_in;

    if ( !memcmp(&p_block->p_buffer[4], "PNG", 3) ) {

        fmt_in.video.i_chroma = VLC_CODEC_PNG;

    }

    else if ( !memcmp(&p_block->p_buffer[4], "JPEG", 4) ) {

        fmt_in.video.i_chroma = VLC_CODEC_JPEG;

    }

    else {

        char psz_image_type[8+1];

        strncpy(psz_image_type, (char*)&p_block->p_buffer[4], 8);

        psz_image_type[sizeof(psz_image_type)-1] = '\0';

        msg_Dbg(p_dec, "Unsupported image format: %s", psz_image_type);

        goto error;

    }

    /* We currently ignore the rest of the header and let the image format

     * handle the details */

    p_block->i_buffer -= i_img_offset;

    p_block->p_buffer += i_img_offset;

    p_pic = image_Read(p_sys->p_image, p_block,

                       &fmt_in,

                       &p_dec->fmt_out.video);

    if (p_pic == NULL) {

        return NULL;

    }

    p_pic->b_force = true;

    p_dec->fmt_out.i_codec = p_dec->fmt_out.video.i_chroma;

    decoder_UpdateVideoFormat(p_dec);

    return p_pic;

error:

    block_Release(p_block);

    return NULL;

}

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

 * CloseDecoder: OggSpots decoder destruction

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

static void CloseDecoder(vlc_object_t* p_this)

{

    decoder_t* p_dec = (decoder_t*)p_this;

    decoder_sys_t* p_sys = p_dec->p_sys;

    image_HandlerDelete(p_sys->p_image);

    free(p_sys);

}