#define _GNU_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <stdint.h>
#include <string.h>
#include <pthread.h>
#include <unistd.h>
#include <alsa/asoundlib.h>
#ifndef M_PI
#define M_PI 3.14159265358979323846
#endif
#define BUFFER_SIZE (1*1024)

snd_output_t *output = NULL;
unsigned char buffer[BUFFER_SIZE];
unsigned int freq = 0;

/*Fonction générant un sinus*/

void generate_sine(unsigned char *buf,unsigned int len, unsigned int freq,float *_Phase){

	int i=0; 
	float phase=*_Phase;
	for(i=0;i<len;i++){   
		*buf= (unsigned char)100*(1+sin(phase+i*freq*2*M_PI/48000));
		buf++;
	}
	*_Phase=phase+(len)*freq*2*M_PI/48000;
}

/*Fonction générant le son*/

void *son(void *arg){
	int err;
	unsigned int i;
	float phase;
	snd_pcm_t *handle;
	snd_pcm_sframes_t frames;
	system("sudo amixer cset numid=3 1");
	for (i = 0; i < sizeof(buffer); i++)
		buffer[i] = random() & 0xff;
	if ((err = snd_pcm_open(&handle,"default", SND_PCM_STREAM_PLAYBACK, 0)) < 0) {
		printf("Playback open error: %s\n", snd_strerror(err));
		exit(EXIT_FAILURE);
	}
	if ((err = snd_pcm_set_params(handle,SND_PCM_FORMAT_U8,SND_PCM_ACCESS_RW_INTERLEAVED,1,48000,1,50000)) < 0) {	/* 0.05sec*/ 
		printf("Playback open error: %s\n", snd_strerror(err));
		exit(EXIT_FAILURE);
	}
	err = snd_output_stdio_attach(&output, stdout, 0);
	snd_pcm_dump(handle, output);
	while(1){
		if(freq!=0){	
			generate_sine(buffer,BUFFER_SIZE,freq*10,&phase);
			frames = snd_pcm_writei(handle, buffer, BUFFER_SIZE);
			if (frames < 0)
				frames = snd_pcm_recover(handle, frames, 0);
			if (frames < 0) 
				break;
		}
	}

	snd_pcm_close(handle);
	(void) arg;
}

/*Lancement du thread gérant la génération du son

int main (int argc, char *argv []){

	pthread_t thread3;	
	if (pthread_create(&thread3, NULL, son, NULL)) {
		perror("pthread_create");
		return EXIT_FAILURE;
	}

	
	if (pthread_join(thread3, NULL)) {
		perror("pthread_join");
		return EXIT_FAILURE;
	}
*/