/*
 * WAV muxer and demuxer
 * Copyright (c) 2001, 2002 Fabrice Bellard
 *
 * 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 "avformat.h"
#include "raw.h"
#include "riff.h"

typedef struct {
    int64_t data;
    int64_t data_end;
    int64_t minpts;
    int64_t maxpts;
    int last_duration;
} WAVContext;

#if CONFIG_WAV_MUXER
static int wav_write_header(AVFormatContext *s)
{
    WAVContext *wav = s->priv_data;
    ByteIOContext *pb = s->pb;
    int64_t fmt, fact;

    put_tag(pb, "RIFF");
    put_le32(pb, 0); /* file length */
    put_tag(pb, "WAVE");

    /* format header */
    fmt = start_tag(pb, "fmt ");
    if (put_wav_header(pb, s->streams[0]->codec) < 0) {
        av_log(s, AV_LOG_ERROR, "%s codec not supported in WAVE format\n",
               s->streams[0]->codec->codec ? s->streams[0]->codec->codec->name : "NONE");
        av_free(wav);
        return -1;
    }
    end_tag(pb, fmt);

    if(s->streams[0]->codec->codec_tag != 0x01 /* hence for all other than PCM */
       && !url_is_streamed(s->pb)) {
        fact = start_tag(pb, "fact");
        put_le32(pb, 0);
        end_tag(pb, fact);
    }

    av_set_pts_info(s->streams[0], 64, 1, s->streams[0]->codec->sample_rate);
    wav->maxpts = wav->last_duration = 0;
    wav->minpts = INT64_MAX;

    /* data header */
    wav->data = start_tag(pb, "data");

    put_flush_packet(pb);

    return 0;
}

static int wav_write_packet(AVFormatContext *s, AVPacket *pkt)
{
    ByteIOContext *pb = s->pb;
    WAVContext *wav = s->priv_data;
    put_buffer(pb, pkt->data, pkt->size);
    if(pkt->pts != AV_NOPTS_VALUE) {
        wav->minpts = FFMIN(wav->minpts, pkt->pts);
        wav->maxpts = FFMAX(wav->maxpts, pkt->pts);
        wav->last_duration = pkt->duration;
    } else
        av_log(s, AV_LOG_ERROR, "wav_write_packet: NOPTS\n");
    return 0;
}

static int wav_write_trailer(AVFormatContext *s)
{
    ByteIOContext *pb = s->pb;
    WAVContext *wav = s->priv_data;
    int64_t file_size;

    if (!url_is_streamed(s->pb)) {
        end_tag(pb, wav->data);

        /* update file size */
        file_size = url_ftell(pb);
        url_fseek(pb, 4, SEEK_SET);
        put_le32(pb, (uint32_t)(file_size - 8));
        url_fseek(pb, file_size, SEEK_SET);

        put_flush_packet(pb);

        if(s->streams[0]->codec->codec_tag != 0x01) {
            /* Update num_samps in fact chunk */
            int number_of_samples;
            number_of_samples = av_rescale(wav->maxpts - wav->minpts + wav->last_duration,
                                           s->streams[0]->codec->sample_rate * (int64_t)s->streams[0]->time_base.num,
                                           s->streams[0]->time_base.den);
            url_fseek(pb, wav->data-12, SEEK_SET);
            put_le32(pb, number_of_samples);
            url_fseek(pb, file_size, SEEK_SET);
            put_flush_packet(pb);
        }
    }
    return 0;
}
#endif /* CONFIG_WAV_MUXER */

/* return the size of the found tag */
/* XXX: > 2GB ? */
static int find_tag(ByteIOContext *pb, uint32_t tag1)
{
    unsigned int tag;
    int size;

    for(;;) {
        if (url_feof(pb))
            return -1;
        tag = get_le32(pb);
        size = get_le32(pb);
        if (tag == tag1)
            break;
        url_fseek(pb, size, SEEK_CUR);
    }
    if (size < 0)
        size = 0x7fffffff;
    return size;
}

static int wav_probe(AVProbeData *p)
{
    /* check file header */
    if (p->buf_size <= 32)
        return 0;
    if (p->buf[0] == 'R' && p->buf[1] == 'I' &&
        p->buf[2] == 'F' && p->buf[3] == 'F' &&
        p->buf[8] == 'W' && p->buf[9] == 'A' &&
        p->buf[10] == 'V' && p->buf[11] == 'E')
        /*
          Since ACT demuxer has standard WAV header at top of it's own,
          returning score is decreased to avoid probe conflict
          between ACT and WAV.
        */
        return AVPROBE_SCORE_MAX - 1;
    else
        return 0;
}

/* Most WAV files with DTS audio are broken and use 0x01 (PCM) as format
   ID instead of 0x2001 (DTS). If the format found is 0x01, check the first
   bytes after 'data' for a valid DTS header. */
static void find_dts_header (ByteIOContext *pb, AVCodecContext *codec)
{
	int sizeLeft = (int)(pb->buf_end - pb->buf_ptr);
	// Make sure there's 2 matches
	int matchesLeft = 2;
	int matchNow = 0;
	int dtsBitSize = 0;
	for (int i = 0; i < sizeLeft; i++)
	{

	  /* 14 bits and little endian bitstream */
	  if (pb->buf_ptr[i] == 0xff && pb->buf_ptr[i+1] == 0x1f &&
		  pb->buf_ptr[i+2] == 0x00 && pb->buf_ptr[i+3] == 0xe8 &&
		  (pb->buf_ptr[i+4] & 0xf0) == 0xf0 && pb->buf_ptr[i+5] == 0x07)
	  {
		  matchNow = 1;
		  dtsBitSize = 14;
	  }

	  /* 14 bits and big endian bitstream */
	  if (pb->buf_ptr[i] == 0x1f && pb->buf_ptr[i+1] == 0xff &&
		  pb->buf_ptr[i+2] == 0xe8 && pb->buf_ptr[i+3] == 0x00 &&
		  pb->buf_ptr[i+4] == 0x07 && (pb->buf_ptr[i+5] & 0xf0) == 0xf0)
	  {
		  matchNow = 1;
		  dtsBitSize = 14;
	  }
    
	  /* 16 bits and little endian bitstream */
	  if (pb->buf_ptr[i] == 0xfe && pb->buf_ptr[i+1] == 0x7f &&
		  pb->buf_ptr[i+2] == 0x01 && pb->buf_ptr[i+3] == 0x80)
	  {
		  matchNow = 1;
		  dtsBitSize = 16;
	  }
    
	  /* 16 bits and big endian bitstream */
	  if (pb->buf_ptr[i] == 0x7f && pb->buf_ptr[i+1] == 0xfe &&
		  pb->buf_ptr[i+2] == 0x80 && pb->buf_ptr[i+3] == 0x01)
	  {
		  matchNow = 1;
		  dtsBitSize = 16;
	  }

	  if (matchNow)
	  {
		matchNow = 0;
		matchesLeft--;
		if (matchesLeft == 0)
		{
			codec->codec_id = CODEC_ID_DTS;
			codec->sub_id = (dtsBitSize == 14) ? 1 : 2;
			break;
		}
	  }
	}
}


/* wav input */
static int wav_read_header(AVFormatContext *s,
                           AVFormatParameters *ap)
{
    int size;
    unsigned int tag;
    ByteIOContext *pb = s->pb;
    AVStream *st;
    WAVContext *wav = s->priv_data;

    /* check RIFF header */
    tag = get_le32(pb);

    if (tag != MKTAG('R', 'I', 'F', 'F'))
        return -1;
    get_le32(pb); /* file size */
    tag = get_le32(pb);
    if (tag != MKTAG('W', 'A', 'V', 'E'))
        return -1;

    /* parse fmt header */
    size = find_tag(pb, MKTAG('f', 'm', 't', ' '));
    if (size < 0)
        return -1;
    st = av_new_stream(s, 0);
    if (!st)
        return AVERROR(ENOMEM);

    get_wav_header(pb, st->codec, size);
    st->need_parsing = AVSTREAM_PARSE_FULL;

    av_set_pts_info(st, 64, 1, st->codec->sample_rate);

    size = find_tag(pb, MKTAG('d', 'a', 't', 'a'));
    if (size < 0)
        return -1;

    wav->data_end= url_ftell(pb) + size;

    /* check if it's really PCM or hidden DTS */
    if (codec_get_id (codec_wav_tags,
                      st->codec->codec_tag) == CODEC_ID_PCM_S16LE)
      find_dts_header (pb, st->codec);
      
    return 0;
}

#define MAX_SIZE 4096

static int wav_read_packet(AVFormatContext *s,
                           AVPacket *pkt)
{
    int ret, size, left;
    AVStream *st;
    WAVContext *wav = s->priv_data;

    if (url_feof(s->pb))
        return AVERROR(EIO);
    st = s->streams[0];

    left= wav->data_end - url_ftell(s->pb);
    if(left <= 0){
        left = find_tag(s->pb, MKTAG('d', 'a', 't', 'a'));
        if (left < 0) {
            return AVERROR(EIO);
        }
        wav->data_end= url_ftell(s->pb) + left;
    }

    size = MAX_SIZE;
    if (st->codec->block_align > 1) {
        if (size < st->codec->block_align)
            size = st->codec->block_align;
        size = (size / st->codec->block_align) * st->codec->block_align;
    }
    size= FFMIN(size, left);
    ret= av_get_packet(s->pb, pkt, size);
    if (ret <= 0)
        return AVERROR(EIO);
    pkt->stream_index = 0;

    /* note: we need to modify the packet size here to handle the last
       packet */
    pkt->size = ret;
    return ret;
}

static int wav_read_seek(AVFormatContext *s,
                         int stream_index, int64_t timestamp, int flags)
{
    AVStream *st;

    st = s->streams[0];
    switch(st->codec->codec_id) {
    case CODEC_ID_MP2:
    case CODEC_ID_MP3:
    case CODEC_ID_AC3:
    case CODEC_ID_DTS:
        /* use generic seeking with dynamically generated indexes */
        return -1;
    default:
        break;
    }
    return pcm_read_seek(s, stream_index, timestamp, flags);
}

#if CONFIG_WAV_DEMUXER
AVInputFormat wav_demuxer = {
    "wav",
    NULL_IF_CONFIG_SMALL("WAV format"),
    sizeof(WAVContext),
    wav_probe,
    wav_read_header,
    wav_read_packet,
    NULL,
    wav_read_seek,
    .flags= AVFMT_GENERIC_INDEX,
    .codec_tag= (const AVCodecTag* const []){codec_wav_tags, 0},
};
#endif
#if CONFIG_WAV_MUXER
AVOutputFormat wav_muxer = {
    "wav",
    NULL_IF_CONFIG_SMALL("WAV format"),
    "audio/x-wav",
    "wav",
    sizeof(WAVContext),
    CODEC_ID_PCM_S16LE,
    CODEC_ID_NONE,
    wav_write_header,
    wav_write_packet,
    wav_write_trailer,
    .codec_tag= (const AVCodecTag* const []){codec_wav_tags, 0},
};
#endif