#define _GNU_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <stdint.h>
#include <string.h>
#include <errno.h>
#include <wiringPi.h>
#include <wiringPiSPI.h>
#include <math.h>
#include <signal.h>
#include <time.h>
#include <pthread.h>
#define	TRUE	            (1==1)
#define	FALSE	            (!TRUE)
#define CHAN_CONFIG_SINGLE  8
#define CHAN_CONFIG_DIFF    0
#define TAILLE 512 
#define CLOCKID CLOCK_REALTIME
#define SIG SIGRTMIN

double data[TAILLE];
int k=0;
int cpt;
int loadSpi=FALSE;
int analogChannel=1;
int spiChannel=0;
int channelConfig=CHAN_CONFIG_SINGLE;

void acquire();

/*Fonction renvoyant la donnée lu sur le bus SPI */

int myAnalogRead(int spiChannel,int channelConfig,int analogChannel){

	if(analogChannel<0 || analogChannel>7)
		return -1;
	unsigned char buffer[3] = {1}; // start bit
	buffer[1] = (channelConfig+analogChannel) << 4;
	wiringPiSPIDataRW(spiChannel, buffer, 3);
	return ( (buffer[1] & 3 ) << 8 ) + buffer[2]; // get last 10 bits
}

/*Fonction d'un timer qui fait appel à aquire() toutes les 4 ms*/

void *ice_time(void *arg){

	timer_t timerid;
	struct sigevent sev;
	struct itimerspec its;
	long long freq_nanosecs;
	sigset_t mask;
	struct sigaction sa;
	sa.sa_flags = SA_SIGINFO;
	sa.sa_sigaction = acquire;
	sigemptyset(&sa.sa_mask);
	
	if (sigaction(SIG, &sa, NULL) == -1)
		errExit("sigaction");
	sigemptyset(&mask);
	if (sigaction(SIG, &sa, NULL) == -1)
		errExit("sigaction");
	sigaddset(&mask, SIG);
	if (sigprocmask(SIG_SETMASK, &mask, NULL) == -1)
		errExit("sigprocmask");   
		       
	sev.sigev_notify = SIGEV_SIGNAL;
	sev.sigev_signo = SIG;
	sev.sigev_value.sival_ptr = &timerid;
	
	if (timer_create(CLOCKID, &sev, &timerid) == -1)
		errExit("timer_create");

	freq_nanosecs = 4000000;
	its.it_value.tv_sec = freq_nanosecs / 1000000000;
	its.it_value.tv_nsec = freq_nanosecs % 1000000000;
	its.it_interval.tv_sec = its.it_value.tv_sec;
	its.it_interval.tv_nsec = its.it_value.tv_nsec;

	if (timer_settime(timerid, 0, &its, NULL) == -1)
		errExit("timer_settime");
	sigprocmask(SIG, &mask, NULL);

	while(1){}
	(void) arg;
   pthread_exit(NULL);
}

/*Fonction récupérant les données acquisent et les stoquant dans le tableau data
Quand le tableau est rempli on enlève la première valeur pour en prendre une nouvelle*/

void acquire( ){
	
	int aux;
	aux = myAnalogRead(spiChannel,channelConfig,analogChannel-1);
	if(k<TAILLE){
		data[k]= aux;
		k++;
	}
	else{
		for(cpt=0;cpt<TAILLE-1;cpt++)
			data[cpt]=data[cpt+1];
		data[cpt]=aux;
	}
}

/*Lancement du thread gérant l'acquisition dans le main

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

	pthread_t thread1;
	if (pthread_create(&thread1, NULL, ice_time, NULL)) {
		perror("pthread_create");
		return EXIT_FAILURE;
	}
	if (pthread_join(thread1, NULL)) {
		perror("pthread_join");
		return EXIT_FAILURE;
	}
	
	*/