#define _CRT_SECURE_NO_WARNINGS

#include "wave.h"

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

char riff[4] = { 'R', 'I', 'F', 'F' };
char wave[4] = { 'W', 'A', 'V', 'E' };
char fmt[4]  = { 'f', 'm', 't', ' ' };
char dat[4]  = { 'd', 'a', 't', 'a' };

void writeWave(const char* filename, int freq, int channels, short* buffer, int samples) {
    struct WaveHeader wh;
    int i;
    int elemWritten;
    FILE *f;

    for(i=0; i<4; i++) {
        wh.riffId[i] = riff[i];
        wh.riffType[i] = wave[i];
        wh.fmtId[i] = fmt[i];
        wh.dataId[i] = dat[i];
    }

    /* Format chunk */
    wh.fmtLen = 16;
    wh.formatTag = 1;  /* PCM */
    wh.channels = channels;
    wh.samplesPerSec =  freq;
    wh.avgBytesPerSec = freq * channels * sizeof(short);
    wh.blockAlign = channels * sizeof(short);
    wh.bitsPerSample = sizeof(short)*8;
    wh.dataLen = samples * channels * sizeof(short);
    wh.len = 36 + wh.dataLen;

    f = fopen(filename,"wb");
    if (!f) {
        printf("error: could not write wave\n");
        return;
    }

    elemWritten = fwrite(&wh, sizeof(wh), 1, f);
    if (elemWritten) elemWritten = fwrite(buffer, wh.dataLen, 1, f);
    fclose(f);

    if (!elemWritten){
        printf("error: could not write wave\n");
    }
}

int readWave(const char* filename, int* freq, int* channels, short** buffer, int* samples) {
    struct WaveHeader wh;
    FILE *f;
    int i;
    int elemsRead;

    memset(&wh, 0, sizeof(wh));

    f = fopen(filename,"rb");
    if (!f) {
        printf("error: could not open wave %s\n",filename);
        return 0;
    }

    fread(&wh, sizeof(wh), 1, f);

    for(i=0; i<4; i++) {
        if ((wh.riffId[i] != riff[i]) ||
            (wh.riffType[i] != wave[i]) ||
            (wh.fmtId[i] != fmt[i]) ||
            (wh.dataId[i] != dat[i])){
                goto closeError;
        }
    }
    // Format chunk
    if (wh.fmtLen != 16) goto closeError;
    if (wh.formatTag != 1) goto closeError;
    *channels = wh.channels;
    if (*channels <1 || *channels >2) goto closeError;
    *freq = wh.samplesPerSec;
    if (wh.blockAlign != *channels * sizeof(short)) goto closeError;
    *samples = wh.dataLen / (*channels * sizeof(short));

    if (*samples < *freq) {
        fclose(f);
        printf("error: wave file is too short\n");
        return 0;
    }

    (*buffer) = (short*) malloc(wh.dataLen);
    if (!*buffer){
        printf("error: could not allocate memory for wave\n");
        return 0;
    }

    elemsRead = fread(*buffer, wh.dataLen, 1, f);
    fclose(f);
    if (elemsRead != 1){
        printf("error: reading wave file\n");
        return 0;
    }

    return 1;

closeError:
    fclose(f);
    printf("error: invalid wave file %s\n",filename);
    return 0;
}