/* -*- c++ -*- */
/*
 * Copyright 2004,2008,2012-2013 Free Software Foundation, Inc.
 *
 * This file is part of GNU Radio
 *
 * GNU Radio is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 3, or (at your option)
 * any later version.
 *
 * GNU Radio 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with GNU Radio; see the file COPYING.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street,
 * Boston, MA 02110-1301, USA.
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <gnuradio/blocks/wavfile.h>
#include <stdint.h>
#include <cstring>

namespace gr {
namespace blocks {
#define VALID_COMPRESSION_TYPE 0x0001

// Basically, this is the opposite of htonx() and ntohx()
// Define host to/from worknet (little endian) short and long
#ifdef GR_IS_BIG_ENDIAN

static inline uint16_t __gri_wav_bs16(uint16_t x) { return (x >> 8) | (x << 8); }

static inline uint32_t __gri_wav_bs32(uint32_t x)
{
    return (uint32_t(__gri_wav_bs16(uint16_t(x & 0xfffful))) << 16) |
           (__gri_wav_bs16(uint16_t(x >> 16)));
}

#define htowl(x) __gri_wav_bs32(x)
#define wtohl(x) __gri_wav_bs32(x)
#define htows(x) __gri_wav_bs16(x)
#define wtohs(x) __gri_wav_bs16(x)

#else

#define htowl(x) uint32_t(x)
#define wtohl(x) uint32_t(x)
#define htows(x) uint16_t(x)
#define wtohs(x) uint16_t(x)

#endif // GR_IS_BIG_ENDIAN

// WAV files are always little-endian, so we need some byte switching macros
static inline uint32_t host_to_wav(uint32_t x) { return htowl(x); }
static inline uint16_t host_to_wav(uint16_t x) { return htows(x); }
static inline int16_t host_to_wav(int16_t x) { return htows(x); }
static inline uint32_t wav_to_host(uint32_t x) { return wtohl(x); }
static inline uint16_t wav_to_host(uint16_t x) { return wtohs(x); }
static inline int16_t wav_to_host(int16_t x) { return wtohs(x); }

bool wavheader_parse(FILE* fp,
                     unsigned int& sample_rate_o,
                     int& nchans_o,
                     int& bytes_per_sample_o,
                     int& first_sample_pos_o,
                     unsigned int& samples_per_chan_o)
{
    // _o variables take return values
    char str_buf[8] = { 0 };

    uint32_t file_size;
    uint32_t fmt_hdr_skip;
    uint16_t compression_type;
    uint16_t nchans;
    uint32_t sample_rate;
    uint32_t avg_bytes_per_sec;
    uint16_t block_align;
    uint16_t bits_per_sample;
    uint32_t chunk_size;

    size_t fresult;

    fresult = fread(str_buf, 1, 4, fp);
    if (fresult != 4 || strncmp(str_buf, "RIFF", 4) || feof(fp)) {
        return false;
    }

    fresult = fread(&file_size, 1, 4, fp);

    fresult = fread(str_buf, 1, 8, fp);
    if (fresult != 8 || strncmp(str_buf, "WAVEfmt ", 8) || feof(fp)) {
        return false;
    }

    fresult = fread(&fmt_hdr_skip, 1, 4, fp);

    fresult = fread(&compression_type, 1, 2, fp);
    if (wav_to_host(compression_type) != VALID_COMPRESSION_TYPE) {
        return false;
    }

    fresult = fread(&nchans, 1, 2, fp);
    fresult = fread(&sample_rate, 1, 4, fp);
    fresult = fread(&avg_bytes_per_sec, 1, 4, fp);
    fresult = fread(&block_align, 1, 2, fp);
    fresult = fread(&bits_per_sample, 1, 2, fp);

    if (ferror(fp)) {
        return false;
    }

    fmt_hdr_skip = wav_to_host(fmt_hdr_skip);
    nchans = wav_to_host(nchans);
    sample_rate = wav_to_host(sample_rate);
    bits_per_sample = wav_to_host(bits_per_sample);

    if (bits_per_sample != 8 && bits_per_sample != 16) {
        return false;
    }

    fmt_hdr_skip -= 16;
    if (fmt_hdr_skip) {
        if (fseek(fp, fmt_hdr_skip, SEEK_CUR) != 0) {
            return false;
        }
    }

    // find data chunk
    fresult = fread(str_buf, 1, 4, fp);
    // keep parsing chunk until we hit the data chunk
    while (fresult != 4 || strncmp(str_buf, "data", 4)) {
        // all good?
        if (fresult != 4 || ferror(fp) || feof(fp)) {
            return false;
        }
        // get chunk body size and skip
        fresult = fread(&chunk_size, 1, 4, fp);
        if (fresult != 4 || ferror(fp) || feof(fp)) {
            return false;
        }
        chunk_size = wav_to_host(chunk_size);
        if (fseek(fp, chunk_size, SEEK_CUR) != 0) {
            return false;
        }
        // read next chunk type
        fresult = fread(str_buf, 1, 4, fp);
    }

    fresult = fread(&chunk_size, 1, 4, fp);
    if (ferror(fp)) {
        return false;
    }

    // More byte swapping
    chunk_size = wav_to_host(chunk_size);

    // Output values
    sample_rate_o = (unsigned)sample_rate;
    nchans_o = (int)nchans;
    bytes_per_sample_o = (int)(bits_per_sample / 8);
    first_sample_pos_o = (int)ftell(fp);
    samples_per_chan_o = (unsigned)(chunk_size / (bytes_per_sample_o * nchans));
    return true;
}


short int wav_read_sample(FILE* fp, int bytes_per_sample)
{
    int16_t buf_16bit = 0;

    if (fread(&buf_16bit, bytes_per_sample, 1, fp) != 1) {
        return 0;
    }
    if (bytes_per_sample == 1) {
        return (short)buf_16bit;
    }
    return (short)wav_to_host(buf_16bit);
}


bool wavheader_write(FILE* fp, unsigned int sample_rate, int nchans, int bytes_per_sample)
{
    const int header_len = 44;
    char wav_hdr[header_len] =
        "RIFF\0\0\0\0WAVEfmt \0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0data\0\0\0";
    uint16_t nchans_f = (uint16_t)nchans;
    uint32_t sample_rate_f = (uint32_t)sample_rate;
    uint16_t block_align = bytes_per_sample * nchans;
    uint32_t avg_bytes = sample_rate * block_align;
    uint16_t bits_per_sample = bytes_per_sample * 8;

    nchans_f = host_to_wav(nchans_f);
    sample_rate_f = host_to_wav(sample_rate_f);
    block_align = host_to_wav(block_align);
    avg_bytes = host_to_wav(avg_bytes);
    bits_per_sample = host_to_wav(bits_per_sample);

    wav_hdr[16] = 0x10; // no extra bytes
    wav_hdr[20] = 0x01; // no compression
    memcpy((void*)(wav_hdr + 22), (void*)&nchans_f, 2);
    memcpy((void*)(wav_hdr + 24), (void*)&sample_rate_f, 4);
    memcpy((void*)(wav_hdr + 28), (void*)&avg_bytes, 4);
    memcpy((void*)(wav_hdr + 32), (void*)&block_align, 2);
    memcpy((void*)(wav_hdr + 34), (void*)&bits_per_sample, 2);

    fwrite(&wav_hdr, 1, header_len, fp);
    if (ferror(fp)) {
        return false;
    }

    return true;
}


void wav_write_sample(FILE* fp, short int sample, int bytes_per_sample)
{
    void* data_ptr;
    unsigned char buf_8bit;
    int16_t buf_16bit;

    if (bytes_per_sample == 1) {
        buf_8bit = (unsigned char)sample;
        data_ptr = (void*)&buf_8bit;
    } else {
        buf_16bit = host_to_wav((int16_t)sample);
        data_ptr = (void*)&buf_16bit;
    }

    fwrite(data_ptr, 1, bytes_per_sample, fp);
}


bool wavheader_complete(FILE* fp, unsigned int byte_count)
{
    uint32_t chunk_size = (uint32_t)byte_count;
    chunk_size = host_to_wav(chunk_size);

    if (fseek(fp, 40, SEEK_SET) != 0) {
        return false;
    }
    fwrite(&chunk_size, 1, 4, fp);

    chunk_size = (uint32_t)byte_count + 36; // fmt chunk and data header
    chunk_size = host_to_wav(chunk_size);
    if (fseek(fp, 4, SEEK_SET) != 0) {
        return false;
    }

    fwrite(&chunk_size, 1, 4, fp);

    if (ferror(fp)) {
        return false;
    }

    return true;
}

} /* namespace blocks */
} /* namespace gr */
