/*
 * Copyright (C) 2016 BlueKitchen GmbH
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the copyright holders nor the names of
 *    contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 * 4. Any redistribution, use, or modification is done solely for
 *    personal benefit and not for any commercial purpose or for
 *    monetary gain.
 *
 * THIS SOFTWARE IS PROVIDED BY BLUEKITCHEN GMBH AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL MATTHIAS
 * RINGWALD OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
 * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * Please inquire about commercial licensing options at 
 * contact@bluekitchen-gmbh.com
 *
 */

#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>
#include <unistd.h>

#include "wav_util.h"
#include "btstack_util.h"

static const uint8_t sine_uint8[] = {
      0,  15,  31,  46,  61,  74,  86,  97, 107, 114,
    120, 124, 126, 126, 124, 120, 114, 107,  97,  86,
     74,  61,  46,  31,  15,   0, 241, 225, 210, 195,
    182, 170, 159, 149, 142, 136, 132, 130, 130, 132,
    136, 142, 149, 159, 170, 182, 195, 210, 225, 241,
};


// input signal: pre-computed sine wave, 160 Hz at 16000 kHz
static const int16_t sine_int16[] = {
     0,    2057,    4107,    6140,    8149,   10126,   12062,   13952,   15786,   17557,
 19260,   20886,   22431,   23886,   25247,   26509,   27666,   28714,   29648,   30466,
 31163,   31738,   32187,   32509,   32702,   32767,   32702,   32509,   32187,   31738,
 31163,   30466,   29648,   28714,   27666,   26509,   25247,   23886,   22431,   20886,
 19260,   17557,   15786,   13952,   12062,   10126,    8149,    6140,    4107,    2057,
     0,   -2057,   -4107,   -6140,   -8149,  -10126,  -12062,  -13952,  -15786,  -17557,
-19260,  -20886,  -22431,  -23886,  -25247,  -26509,  -27666,  -28714,  -29648,  -30466,
-31163,  -31738,  -32187,  -32509,  -32702,  -32767,  -32702,  -32509,  -32187,  -31738,
-31163,  -30466,  -29648,  -28714,  -27666,  -26509,  -25247,  -23886,  -22431,  -20886,
-19260,  -17557,  -15786,  -13952,  -12062,  -10126,   -8149,   -6140,   -4107,   -2057,
};

static int phase = 0;

static int wav_reader_fd;
static int bytes_per_sample = 2;

/* Write wav file utils */
typedef struct wav_writer_state {
    FILE * wav_file;
    int total_num_samples;
    int num_channels;
    int sampling_frequency;
    int frame_count;
} wav_writer_state_t;

wav_writer_state_t wav_writer_state;


static void little_endian_fstore_16(FILE *wav_file, uint16_t value){
    uint8_t buf[2];
    little_endian_store_16(buf, 0, value);
    fwrite(&buf, 1, 2, wav_file);
}

static void little_endian_fstore_32(FILE *wav_file, uint32_t value){
    uint8_t buf[4];
    little_endian_store_32(buf, 0, value);
    fwrite(&buf, 1, 4, wav_file);
}

static ssize_t __read(int fd, void *buf, size_t count){
    ssize_t len, pos = 0;

    while (count > 0) {
        len = read(fd, (int8_t * )buf + pos, count);
        if (len <= 0)
            return pos;

        count -= len;
        pos   += len;
    }
    return pos;
}

static void write_wav_header(FILE * wav_file,  int total_num_samples, int num_channels, int sample_rate){
    unsigned int write_with_bytes_per_sample = 2;
    /* write RIFF header */
    fwrite("RIFF", 1, 4, wav_file);
    // num_samples = blocks * subbands
    uint32_t data_bytes = (uint32_t) (write_with_bytes_per_sample * total_num_samples * num_channels);
    little_endian_fstore_32(wav_file, data_bytes + 36); 
    fwrite("WAVE", 1, 4, wav_file);

    int byte_rate = sample_rate * num_channels * write_with_bytes_per_sample;
    int bits_per_sample = 8 * write_with_bytes_per_sample;
    int block_align = num_channels * bits_per_sample;
    int fmt_length = 16;
    int fmt_format_tag = 1; // PCM

    /* write fmt chunk */
    fwrite("fmt ", 1, 4, wav_file);
    little_endian_fstore_32(wav_file, fmt_length);
    little_endian_fstore_16(wav_file, fmt_format_tag);
    little_endian_fstore_16(wav_file, num_channels);
    little_endian_fstore_32(wav_file, sample_rate);
    little_endian_fstore_32(wav_file, byte_rate);
    little_endian_fstore_16(wav_file, block_align);   
    little_endian_fstore_16(wav_file, bits_per_sample);
    
    /* write data chunk */
    fwrite("data", 1, 4, wav_file); 
    little_endian_fstore_32(wav_file, data_bytes);
}

int wav_writer_open(const char * filepath, int num_channels, int sampling_frequency){
    FILE * wav_file = fopen(filepath, "wb");
    if (!wav_file) return 1;

    wav_writer_state.wav_file = wav_file;
    wav_writer_state.frame_count = 0;
    wav_writer_state.total_num_samples = 0;
    wav_writer_state.num_channels = num_channels;
    wav_writer_state.sampling_frequency = sampling_frequency;
    write_wav_header(wav_writer_state.wav_file, 0, num_channels, sampling_frequency);
    return 0;
}

int wav_writer_close(void){
    rewind(wav_writer_state.wav_file);
    write_wav_header(wav_writer_state.wav_file, wav_writer_state.total_num_samples, 
        wav_writer_state.num_channels, wav_writer_state.sampling_frequency);
    fclose(wav_writer_state.wav_file);
    return 0;
}

int wav_writer_write_int8(int num_samples, int8_t * data){
    if (data == NULL) return 1;
    int i = 0;
    int8_t zero_byte = 0;
    for (i=0; i<num_samples; i++){
        fwrite(&zero_byte, 1, 1, wav_writer_state.wav_file);
        uint8_t byte_value = (uint8_t)data[i];
        fwrite(&byte_value, 1, 1, wav_writer_state.wav_file);
    }
    
    wav_writer_state.total_num_samples+=num_samples;
    wav_writer_state.frame_count++;
    return 0;
}

int wav_writer_write_int16(int num_samples, int16_t * data){
    if (data == NULL) return 1;
    fwrite(data, num_samples, 2, wav_writer_state.wav_file);
    
    wav_writer_state.total_num_samples+=num_samples;
    wav_writer_state.frame_count++;
    return 0;
}

int wav_reader_open(const char * filepath){
    wav_reader_fd = open(filepath, O_RDONLY); 
    if (!wav_reader_fd) {
        printf("Can't open file %s", filepath);
        return 1;
    }

    uint8_t buf[40];
    __read(wav_reader_fd, buf, sizeof(buf));

    int num_channels = little_endian_read_16(buf, 22);
    int block_align = little_endian_read_16(buf, 32);
    bytes_per_sample = block_align/num_channels;
    if (bytes_per_sample > 2){
        bytes_per_sample = bytes_per_sample/8;
    }
    return 0;
}

int wav_reader_close(void){
    close(wav_reader_fd);
    return 0;
}

// Wav data: 8bit is uint8_t; 16bit is int16
int wav_reader_read_int8(int num_samples, int8_t * data){
    if (!wav_reader_fd) return 1;
    int i;
    int bytes_read = 0;  

    for (i=0; i<num_samples; i++){
        if (bytes_per_sample == 2){
            uint8_t buf[2];
            bytes_read +=__read(wav_reader_fd, &buf, 2);
            data[i] = buf[1];    
        } else {
            uint8_t buf[1];
            bytes_read +=__read(wav_reader_fd, &buf, 1);
            data[i] = buf[0] + 128;
        }
    }
    return bytes_read == num_samples*bytes_per_sample;
}

int wav_reader_read_int16(int num_samples, int16_t * data){
    if (!wav_reader_fd) return 1;
    int i;
    int bytes_read = 0;  
    for (i=0; i<num_samples; i++){
        uint8_t buf[2];
        bytes_read +=__read(wav_reader_fd, &buf, 2);
        data[i] = little_endian_read_16(buf, 0);  
    }
    return bytes_read == num_samples*bytes_per_sample;
}

void wav_synthesize_sine_wave_int8(int num_samples, int8_t * data){
    int i;
    for (i=0; i<num_samples; i++){
        data[i] = (int8_t)sine_uint8[phase];
        phase++;
        if (phase >= sizeof(sine_uint8)) phase = 0;
    }  
}

void wav_synthesize_sine_wave_int16(int num_samples, int16_t * data){
    int i;
    for (i=0; i < num_samples; i++){
        data[i] = sine_int16[phase++];
        if (phase >= (sizeof(sine_int16) / sizeof(int16_t))){
            phase = 0;
        }
    }
}