/*

 * VPK demuxer

 * Copyright (c) 2015 Paul B Mahol

 *

 * 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 "libavutil/intreadwrite.h"

#include "avformat.h"

#include "demux.h"

#include "internal.h"

typedef struct VPKDemuxContext {

    unsigned data_start;

    unsigned block_count;

    unsigned current_block;

    unsigned last_block_size;

} VPKDemuxContext;

static int vpk_probe(const AVProbeData *p)

{

    if (AV_RL32(p->buf) != MKBETAG('V','P','K',' '))

        return 0;

    return AVPROBE_SCORE_MAX / 3 * 2;

}

static int vpk_read_header(AVFormatContext *s)

{

    VPKDemuxContext *vpk = s->priv_data;

    unsigned offset;

    unsigned samples_per_block;

    AVStream *st;

    vpk->current_block = 0;

    st = avformat_new_stream(s, NULL);

    if (!st)

        return AVERROR(ENOMEM);

    avio_skip(s->pb, 4);

    st->duration           = avio_rl32(s->pb) * 28 / 16;

    offset                 = avio_rl32(s->pb);

    st->codecpar->codec_type  = AVMEDIA_TYPE_AUDIO;

    st->codecpar->codec_id    = AV_CODEC_ID_ADPCM_PSX;

    st->codecpar->block_align = avio_rl32(s->pb);

    st->codecpar->sample_rate = avio_rl32(s->pb);

    if (st->codecpar->sample_rate <= 0 || st->codecpar->block_align <= 0)

        return AVERROR_INVALIDDATA;

    st->codecpar->ch_layout.nb_channels = avio_rl32(s->pb);

    if (st->codecpar->ch_layout.nb_channels <= 0)

        return AVERROR_INVALIDDATA;

    samples_per_block      = ((st->codecpar->block_align / st->codecpar->ch_layout.nb_channels) * 28LL) / 16;

    if (samples_per_block <= 0)

        return AVERROR_INVALIDDATA;

    vpk->block_count       = (st->duration + (samples_per_block - 1)) / samples_per_block;

    vpk->last_block_size   = (st->duration % samples_per_block) * 16 * st->codecpar->ch_layout.nb_channels / 28;

    if (offset < avio_tell(s->pb))

        return AVERROR_INVALIDDATA;

    avio_skip(s->pb, offset - avio_tell(s->pb));

    vpk->data_start = offset;

    avpriv_set_pts_info(st, 64, 1, st->codecpar->sample_rate);

    return 0;

}

static int vpk_read_packet(AVFormatContext *s, AVPacket *pkt)

{

    AVCodecParameters *par = s->streams[0]->codecpar;

    VPKDemuxContext *vpk = s->priv_data;

    int ret, i;

    vpk->current_block++;

    if (vpk->current_block == vpk->block_count) {

        unsigned size = vpk->last_block_size / par->ch_layout.nb_channels;

        unsigned skip = (par->block_align - vpk->last_block_size) / par->ch_layout.nb_channels;

        uint64_t pos = avio_tell(s->pb);

        ret = av_new_packet(pkt, vpk->last_block_size);

        if (ret < 0)

            return ret;

        for (i = 0; i < par->ch_layout.nb_channels; i++) {

            ret = avio_read(s->pb, pkt->data + i * size, size);

            avio_skip(s->pb, skip);

            if (ret != size) {

                return AVERROR(EIO);

            }

        }

        pkt->pos = pos;

        pkt->stream_index = 0;

    } else if (vpk->current_block < vpk->block_count) {

        ret = av_get_packet(s->pb, pkt, par->block_align);

        pkt->stream_index = 0;

    } else {

        return AVERROR_EOF;

    }

    return ret;

}

static int vpk_read_seek(AVFormatContext *s, int stream_index,

                         int64_t timestamp, int flags)

{

    AVStream *st = s->streams[stream_index];

    AVCodecParameters *par = st->codecpar;

    VPKDemuxContext *vpk = s->priv_data;

    int samples_per_block;

    int64_t ret = 0;

    samples_per_block = av_get_audio_frame_duration2(par, par->block_align);

    if (samples_per_block > 0)

        timestamp /= samples_per_block;

    else

        return -1;

    ret = avio_seek(s->pb, vpk->data_start + timestamp * par->block_align, SEEK_SET);

    if (ret < 0)

        return ret;

    vpk->current_block = timestamp;

    avpriv_update_cur_dts(s, st, timestamp * samples_per_block);

    return 0;

}

const FFInputFormat ff_vpk_demuxer = {

    .p.name         = "vpk",

    .p.long_name    = NULL_IF_CONFIG_SMALL("Sony PS2 VPK"),

    .p.extensions   = "vpk",

    .priv_data_size = sizeof(VPKDemuxContext),

    .read_probe     = vpk_probe,

    .read_header    = vpk_read_header,

    .read_packet    = vpk_read_packet,

    .read_seek      = vpk_read_seek,

};