#include <stdio.h>
#include <stdlib.h>

typedef struct {
    char chunkId[4];
    int chunkSize;
    char format[4];
    char subchunk1Id[4];
    int subchunk1Size;
    short audioFormat;
    short numChannels;
    int sampleRate;
    int byteRate;
    short blockAlign;
    short bitsPerSample;
    char subchunk2Id[4];
    int subchunk2Size;
} WavHeader;

int main(int argc, char**argv) {
    const char* infile = argv[1];
    FILE* infp = fopen(infile, "rb");
    if (!infp) {
        printf("Failed to open input file %s.\n", infile);
        return 1;
    }

    const char* outfile = argv[2];
    FILE* outfp = fopen(outfile, "wb");
    if (!outfp) {
        printf("Failed to open input file %s.\n", infile);
        return 1;
    }

    // Read WAV file header
    WavHeader wavHeader;
    fread(&wavHeader, sizeof(WavHeader), 1, infp);
    if (strncmp(wavHeader.chunkId, "RIFF", 4) != 0 ||
        strncmp(wavHeader.format, "WAVE", 4) != 0 ||
        strncmp(wavHeader.subchunk1Id, "fmt ", 4) != 0 ||
        wavHeader.audioFormat != 1) {
        printf("Invalid WAV file.\n");
        fclose(infp);
        return 1;
    }

    // Calculate number of samples and bytes per sample
    int numSamples = wavHeader.subchunk2Size / (wavHeader.numChannels * (wavHeader.bitsPerSample / 8));
    int bytesPerSample = wavHeader.bitsPerSample / 8;

    // Allocate memory for audio data
    float* buffer = (float*) malloc(numSamples * wavHeader.numChannels * sizeof(float));
    if (!buffer) {
        printf("Failed to allocate memory.\n");
        fclose(infp);
        return 1;
    }

    // Read audio data and convert to float
    int i, j;
    short sampleValue;
    for (i = 0; i < numSamples; i++) {
        for (j = 0; j < wavHeader.numChannels; j++) {
            fread(&sampleValue, bytesPerSample, 1, infp);
            buffer[i * wavHeader.numChannels + j] = (float) sampleValue / 32768.0f;
        }
    }

    // Print some information about the audio data
    printf("Input file: %s\n", infile);
    printf("Format: %d-channel s16le, %d Hz\n", wavHeader.numChannels, wavHeader.sampleRate);
    printf("Duration: %.3f seconds\n", (float) numSamples / wavHeader.sampleRate);

    // write to output file.
    fwrite(buffer, numSamples * wavHeader.numChannels * sizeof(float), 1, outfp);

    // Clean up
    free(buffer);
    fclose(infp);
    fclose(outfp);

    return 0;
}