/*

 * MOFLEX demuxer

 * Copyright (c) 2015-2016 Florian Nouwt

 * Copyright (c) 2017 Adib Surani

 * Copyright (c) 2020 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 "libavcodec/bytestream.h"

#include "avformat.h"

#include "demux.h"

#include "internal.h"

typedef struct BitReader {

    unsigned last;

    unsigned pos;

} BitReader;

typedef struct MOFLEXDemuxContext {

    unsigned size;

    int64_t pos;

    int64_t ts;

    int flags;

    int in_block;

    BitReader br;

} MOFLEXDemuxContext;

static int pop(BitReader *br, AVIOContext *pb)

{

    if (avio_feof(pb))

        return AVERROR_EOF;

    if ((br->pos & 7) == 0)

        br->last = (unsigned)avio_r8(pb) << 24U;

    else

        br->last <<= 1;

    br->pos++;

    return !!(br->last & 0x80000000);

}

static int pop_int(BitReader *br, AVIOContext *pb, int n)

{

    int value = 0;

    for (int i = 0; i < n; i++) {

        int ret = pop(br, pb);

        if (ret < 0)

            return ret;

        if (ret > INT_MAX - value - value)

            return AVERROR_INVALIDDATA;

        value = 2 * value + ret;

    }

    return value;

}

static int pop_length(BitReader *br, AVIOContext *pb)

{

    int ret, n = 1;

    while ((ret = pop(br, pb)) == 0)

        n++;

    if (ret < 0)

        return ret;

    return n;

}

static int read_var_byte(AVFormatContext *s, unsigned *out)

{

    AVIOContext *pb = s->pb;

    unsigned value = 0, data;

    data = avio_r8(pb);

    if (!(data & 0x80)) {

        *out = data;

        return 0;

    }

    value = (data & 0x7F) << 7;

    data = avio_r8(pb);

    if (!(data & 0x80)) {

        value |= data;

        *out = value;

        return 0;

    }

    value = ((data & 0x7F) | value) << 7;

    data = avio_r8(pb);

    if (!(data & 0x80)) {

        value |= data;

        *out = value;

        return 0;

    }

    value = (((data & 0x7F) | value) << 7) | avio_r8(pb);

    *out = value;

    return 0;

}

static int moflex_probe(const AVProbeData *p)

{

    GetByteContext gb;

    int score = 0;

    bytestream2_init(&gb, p->buf, p->buf_size);

    if (bytestream2_get_be16(&gb) != 0x4C32)

        return 0;

    score += 10;

    bytestream2_skip(&gb, 10);

    if (bytestream2_get_be16(&gb) == 0)

        return 0;

    score += 5;

    while (bytestream2_get_bytes_left(&gb) > 0) {

        int type = bytestream2_get_byte(&gb);

        int size = bytestream2_get_byte(&gb);

        if (type == 0) {

            score += 5 * (size == 0);

            break;

        }

        if ((type == 1 && size == 12) ||

            (type == 2 && size ==  6) ||

            (type == 3 && size == 13) ||

            (type == 4 && size ==  2))

            score += 20;

        bytestream2_skip(&gb, size);

    }

    return FFMIN(AVPROBE_SCORE_MAX, score);

}

static int moflex_read_sync(AVFormatContext *s)

{

    MOFLEXDemuxContext *m = s->priv_data;

    AVIOContext *pb = s->pb;

    if (avio_rb16(pb) != 0x4C32) {

        if (avio_feof(pb))

            return AVERROR_EOF;

        avio_seek(pb, -2, SEEK_CUR);

        return 1;

    }

    avio_skip(pb, 2);

    m->ts = avio_rb64(pb);

    m->size = avio_rb16(pb) + 1;

    while (!avio_feof(pb)) {

        unsigned type, ssize, codec_id = 0;

        unsigned codec_type, width = 0, height = 0, sample_rate = 0, channels = 0;

        int stream_index = -1;

        AVRational tb = av_make_q(0, 1);

        read_var_byte(s, &type);

        read_var_byte(s, &ssize);

        switch (type) {

        case 0:

            if (ssize > 0)

                avio_skip(pb, ssize);

            return 0;

        case 2:

            codec_type = AVMEDIA_TYPE_AUDIO;

            stream_index = avio_r8(pb);

            codec_id = avio_r8(pb);

            switch (codec_id) {

            case 0: codec_id = AV_CODEC_ID_FASTAUDIO; break;

            case 1: codec_id = AV_CODEC_ID_ADPCM_IMA_MOFLEX; break;

            case 2: codec_id = AV_CODEC_ID_PCM_S16LE; break;

            default:

                av_log(s, AV_LOG_ERROR, "Unsupported audio codec: %d\n", codec_id);

                return AVERROR_PATCHWELCOME;

            }

            sample_rate = avio_rb24(pb) + 1;

            tb = av_make_q(1, sample_rate);

            channels = avio_r8(pb) + 1;

            break;

        case 1:

        case 3:

            codec_type = AVMEDIA_TYPE_VIDEO;

            stream_index = avio_r8(pb);

            codec_id = avio_r8(pb);

            switch (codec_id) {

            case 0: codec_id = AV_CODEC_ID_MOBICLIP; break;

            default:

                av_log(s, AV_LOG_ERROR, "Unsupported video codec: %d\n", codec_id);

                return AVERROR_PATCHWELCOME;

            }

            tb.den = avio_rb16(pb);

            tb.num = avio_rb16(pb);

            width = avio_rb16(pb);

            height = avio_rb16(pb);

            avio_skip(pb, type == 3 ? 3 : 2);

            break;

        case 4:

            codec_type = AVMEDIA_TYPE_DATA;

            stream_index = avio_r8(pb);

            avio_skip(pb, 1);

            break;

        }

        if (stream_index == s->nb_streams) {

            AVStream *st = avformat_new_stream(s, NULL);

            if (!st)

                return AVERROR(ENOMEM);

            st->codecpar->codec_type = codec_type;

            st->codecpar->codec_id   = codec_id;

            st->codecpar->width      = width;

            st->codecpar->height     = height;

            st->codecpar->sample_rate= sample_rate;

            st->codecpar->ch_layout.nb_channels = channels;

            st->priv_data            = av_packet_alloc();

            if (!st->priv_data)

                return AVERROR(ENOMEM);

            if (tb.num)

                avpriv_set_pts_info(st, 63, tb.num, tb.den);

        }

    }

    return 0;

}

static int moflex_read_header(AVFormatContext *s)

{

    int ret;

    ret = moflex_read_sync(s);

    if (ret < 0)

        return ret;

    s->ctx_flags |= AVFMTCTX_NOHEADER;

    avio_seek(s->pb, 0, SEEK_SET);

    return 0;

}

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

{

    MOFLEXDemuxContext *m = s->priv_data;

    AVIOContext *pb = s->pb;

    BitReader *br = &m->br;

    int ret;

    while (!avio_feof(pb)) {

        if (!m->in_block) {

            m->pos = avio_tell(pb);

            ret = moflex_read_sync(s);

            if (ret < 0)

                return ret;

            m->flags = avio_r8(pb);

            if (m->flags & 2)

                avio_skip(pb, 2);

        }

        while ((avio_tell(pb) < m->pos + m->size) && !avio_feof(pb) && avio_r8(pb)) {

            int stream_index, bits, pkt_size, endframe;

            AVPacket *packet;

            m->in_block = 1;

            avio_seek(pb, -1, SEEK_CUR);

            br->pos = br->last = 0;

            bits = pop_length(br, pb);

            if (bits < 0)

                return bits;

            stream_index = pop_int(br, pb, bits);

            if (stream_index < 0)

                return stream_index;

            if (stream_index >= s->nb_streams)

                return AVERROR_INVALIDDATA;

            endframe = pop(br, pb);

            if (endframe < 0)

                return endframe;

            if (endframe) {

                bits = pop_length(br, pb);

                if (bits < 0)

                    return bits;

                pop_int(br, pb, bits);

                pop(br, pb);

                bits = pop_length(br, pb);

                if (bits < 0)

                    return bits;

                pop_int(br, pb, bits * 2 + 26);

            }

            pkt_size = pop_int(br, pb, 13) + 1;

            if (pkt_size > m->size)

                return AVERROR_INVALIDDATA;

            packet   = s->streams[stream_index]->priv_data;

            if (!packet) {

                avio_skip(pb, pkt_size);

                continue;

            }

            ret = av_append_packet(pb, packet, pkt_size);

            if (ret < 0)

                return ret;

            if (endframe && packet->size > 0) {

                av_packet_move_ref(pkt, packet);

                pkt->pos = m->pos;

                pkt->stream_index = stream_index;

                if (s->streams[stream_index]->codecpar->codec_type == AVMEDIA_TYPE_VIDEO) {

                    pkt->duration = 1;

                    if (pkt->data[0] & 0x80)

                        pkt->flags |= AV_PKT_FLAG_KEY;

                } else {

                    pkt->flags |= AV_PKT_FLAG_KEY;

                }

                return ret;

            }

        }

        m->in_block = 0;

        if (m->flags % 2 == 0) {

            if (m->size <= 0)

                return AVERROR_INVALIDDATA;

            avio_seek(pb, m->pos + m->size, SEEK_SET);

        }

    }

    return AVERROR_EOF;

}

static int moflex_read_seek(AVFormatContext *s, int stream_index,

                            int64_t pts, int flags)

{

    MOFLEXDemuxContext *m = s->priv_data;

    m->in_block = 0;

    return -1;

}

static int moflex_read_close(AVFormatContext *s)

{

    for (int i = 0; i < s->nb_streams; i++) {

        av_packet_free((AVPacket **)&s->streams[i]->priv_data);

    }

    return 0;

}

const FFInputFormat ff_moflex_demuxer = {

    .p.name         = "moflex",

    .p.long_name    = NULL_IF_CONFIG_SMALL("MobiClip MOFLEX"),

    .p.extensions   = "moflex",

    .p.flags        = AVFMT_GENERIC_INDEX,

    .priv_data_size = sizeof(MOFLEXDemuxContext),

    .read_probe     = moflex_probe,

    .read_header    = moflex_read_header,

    .read_packet    = moflex_read_packet,

    .read_seek      = moflex_read_seek,

    .read_close     = moflex_read_close,

    .flags_internal = FF_INFMT_FLAG_INIT_CLEANUP,

};