#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <stdint.h>

#define RIFF_MAGIC_NUMBER "RIFF"
#define WAV_MAGIC_NUMBER  "WAVE"

struct wav_chunk
{
    uint8_t  chunk_id[4];
    uint32_t chunk_size;
};

struct wav_format
{
    uint16_t format_tag;            // format code
    uint16_t nr_channels;           // interleaved channels
    uint32_t sample_rate;           // blocks per second
    uint32_t data_rate;             // bytes per second
    uint16_t block_size;            // in bytes
    uint16_t bit_depth;             // bits per sample
    uint16_t cb_size;               // size of the extension (0 or 22)
    uint16_t valid_bits_per_sample; // Number of valid bits  // only if chunk_size >= 18
    uint32_t dw_channel_mask;       // Speaker position mask // only if chunk_size == 40
    uint8_t  sub_format[16];        // GUID                  // only if chunk_size == 40
};

int main(int argc, char** argv)
{
    FILE* wave_file = fopen(argv[1], "r");
    if (!wave_file)
    {
        printf("Error opening %s: %s\n", argv[1], strerror(errno));
        exit(-1);
    }

    char* file_buf = NULL;
    long  file_len = 0;

    fseek(wave_file, 0, SEEK_END);    // Jump to the end of the file
    file_len = ftell(wave_file);      // Get the current byte offset in the file
    rewind(wave_file);                // Jump back to the beginning of the file

    file_buf = (char *) malloc(file_len * sizeof(char));
    fread(file_buf, file_len, 1, wave_file); // Read in the entire file
    fclose(wave_file);

    char riff_magic_nr[4] = {file_buf[0], file_buf[1], file_buf[2],  file_buf[3] };
    char wav_magic_nr[4]  = {file_buf[8], file_buf[9], file_buf[10], file_buf[11]};
    if ((strcmp(riff_magic_nr, RIFF_MAGIC_NUMBER) != 0) ||
        (strcmp(wav_magic_nr, WAV_MAGIC_NUMBER)   != 0))
    {
        printf("Could not recognize file format of '%s'\n", argv[1]);
        free(file_buf);
        exit(-1);
    }

    return 0;
}