// Josiah Boning
//
// input.c
// Code to read in a variety of audio filetypes
// Currently only supports .WAV
//

#include "project.h"
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <fftw3.h>

/**
 * The high-level read-me-a-file function.
 *
 * This basically just passes the file off the correct file-reading routine
 * based on filetype.
 */
int input(char filename[], double** arrayptr) {
	if (strstr(filename, ".wav")-filename == strlen(filename) - strlen(".wav")) {
		return readWav(filename, arrayptr);
	}
}

/**
 * Read in a WAV file.
 *
 * Processess a WAV file into raw waveform data. Currently only supports WAV
 * files with PCM encoding, one track of audio data (mono), a 44.1 khz sample
 * rate, and 8-bit unsigned integer sampling.
 */
int readWav(char filename[], double** arrayptr) {
	FILE* fin;
	char string[1024];
	int size, samplerate, byterate;
	short audiofmt, numchannels, blockalign, bitspersample;
	int i;
	unsigned char tmp;
	double* datas;

	fin=fopen(filename,"r");

	fread(string, sizeof(char), 4, fin); // "RIFF"
	if (strncmp(string, "RIFF", 4)) {
		printf("Not a valid WAV file!\n");
		exit(0);
	}
	fread(string, sizeof(char), 4, fin);
	fread(string, sizeof(char), 4, fin); // "WAVE"
	if (strncmp(string, "WAVE", 4)) {
		printf("Not a valid WAV file!\n");
		exit(0);
	}
	fread(string, sizeof(char), 4, fin); // "fmt "
	if (strncmp(string, "fmt ", 4)) {
		printf("Not a valid WAV file!\n");
		exit(0);
	}

	fread(&size, sizeof(char), 4, fin);
	fread(&audiofmt, sizeof(char), 2, fin);
	if (audiofmt != 1) {
		printf("The WAV file must use PCM encoding.\n");
		exit(0);
	}
	fread(&numchannels, sizeof(char), 2, fin);
	if (numchannels != 1) {
		printf("The WAV file must be mono.\n");
		exit(0);
	}
	fread(&samplerate, sizeof(char), 4, fin);
	if (samplerate != 44100) {
		printf("The WAV file must have 44100 samples/sec.\n");
		exit(0);
	}
	fread(&byterate, sizeof(char), 4, fin);
	fread(&blockalign, sizeof(char), 2, fin);
	fread(&bitspersample, sizeof(char), 2, fin);
	if (bitspersample != 8) {
		printf("The WAV file must use 8-bit sampling.\n");
		exit(0);
	}

	fread(string, sizeof(char), 4, fin);
	if (strncmp(string, "data", 4)) {
		printf("Malformed WAV file.\n");
		exit(0);
	}
	fread(&size, sizeof(char), 4, fin);

	//printf("%i\n", size);

	//size = 1 * ITEMS_PER_TRANS;
	int numitems = size;

	datas = (double*) fftw_malloc(size * sizeof(double));

	for (i = 0; i < numitems; i++) {
		fread(&tmp, sizeof(char), 1, fin);
		datas[i] = (double) tmp - 128;
	}

	fclose(fin);

	*arrayptr = datas;
	return numitems;
}