#include <stdlib.h>
#include <stdio.h>
#include <stdbool.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <math.h>
#include <time.h>

#include "fifo.h"

void* input_fifo(void* data) {
	struct audio_data* audio = (struct audio_data *) data;
	int fd;
	int n = 0;
	signed char buf[1024];
	int tempr, templ, lo;
	int q, i;
	int t = 0;
	int size = 1024;
	int bytes = 0;
	int flags;
	struct timespec req = { .tv_sec = 0, .tv_nsec = 10000000 };
    
	fd = open(audio->source, O_RDONLY);
	flags = fcntl(fd, F_GETFL, 0);
	fcntl(fd, F_SETFL, flags | O_NONBLOCK);
    
	while (1) {
		bytes = read(fd, buf, sizeof(buf));
        
		if (bytes == -1) { /* if no bytes read, sleep 10ms and zero shared buffer */
			nanosleep (&req, NULL);
			t++;
			if (t > 10) {
				for (i = 0; i < 2048; i++)audio->audio_out_l[i] = 0;
				for (i = 0; i < 2048; i++)audio->audio_out_r[i] = 0;
				t = 0;
			}
		} else { /* if bytes read, go ahead */
			t = 0;
			for (q = 0; q < (size / 4); q++) {
                
				tempr = (buf[4 * q + 3] << 2);
                
				lo =  (buf[4 * q + 2] >> 6);
				if (lo < 0) lo = abs(lo) + 1;
				if (tempr >= 0) tempr = tempr + lo;
				else tempr = tempr - lo;
                
				templ = (buf[4 * q + 1] << 2);
                
				lo =  (buf[4 * q] >> 6);
				if (lo < 0) lo = abs(lo) + 1;
				if (templ >= 0) templ = templ + lo;
				else templ = templ - lo;
                
				if (audio->channels == 1) audio->audio_out_l[n] = (tempr + templ) / 2;
                
				/* stereo storing channels in buffer */
				if (audio->channels == 2) {
					audio->audio_out_l[n] = templ;
					audio->audio_out_r[n] = tempr;
                }
                
				n++;
				if (n == 2048 - 1)n = 0;
			}
		}
        
		if (audio->terminate == 1) {
			close(fd);
			break;
		}
        
	}
    
	return 0;
}