#include <unistd.h>
#include <time.h>
#include <signal.h>
#include <stdio.h>
#include <sys/queue.h>
#include <stdlib.h>
#include <string.h>
#include <err.h>
#include <sys/file.h>

/*
 * signal and timer example
 *
 * timerTest.c
 */

/*
 * map timer code to a string
 *
 */

#define MAX_LEN_NAME 128

SLIST_HEAD(slisthead, entry) head = SLIST_HEAD_INITIALIZER(head);
struct slisthead *headp;	/* Singly-linked List head. */
struct entry {
	char	       *name;
	int		code;
	SLIST_ENTRY(entry) entries;	/* Singly-linked List. */
}   *np;

/*
 * signal handler
 *
 */

static int	spankme;

void
sigHandler(int signo, siginfo_t * si, void * /* ucontext_t */ uap)
{
	switch (signo) {
	case SIGALRM:
		/* timer timeout */
		SLIST_FOREACH(np, &head, entries) {
			if (np && np->code == si->si_value.sival_int) {
				flockfile(stdout);
				printf("%s", np->name);
				fflush(stdout);
				funlockfile(stdout);
				break;
			}
		}
		if (np == NULL)
			printf("Timeout #%d, unknown.\n", si->si_value.sival_int);
		break;
	case SIGINFO:
		printf("no need to panic.\n");
		break;
	case SIGINT:
		/* exit flag */
		++spankme;
		break;
	default:
		printf("sig:%d received.", signo);
		break;
	}

}

int
main(int argc, char *argv[])
{
	SLIST_INIT(&head);
	/* timer pointers */
	size_t		nb_timers = 5;
	size_t		cols = 0;
	

	if (argc > 1) {
		nb_timers = atoi(argv[1]);
	}

	if (nb_timers < 1) {
		fprintf(stderr, "Invalid timer number.\n");
		abort();
	}

	timer_t		timerid[nb_timers];
	char	       *names[nb_timers];

	/* build text to display for each */
	for (size_t i = 0; i < nb_timers; ++i) {

		names[i] = malloc(MAX_LEN_NAME);
		if (i == 0) {
			strncpy(names[i], ".", MAX_LEN_NAME);
			continue;
		}
		if (MAX_LEN_NAME <= snprintf(names[i], MAX_LEN_NAME, "%c", (char)('A' + i - 1))) {
			warnx("string %zu shorten", i);
		}
	}

	/* signal */
	struct sigaction sa;
	sa.sa_handler = NULL;
	sa.sa_sigaction = &sigHandler;
	sa.sa_flags = SA_SIGINFO;
	sigemptyset(&sa.sa_mask);
	if (sigaction(SIGINFO, &sa, NULL)) {
		warn("SIGNFO not caught.");
	}
	if (sigaction(SIGALRM, &sa, NULL)) {
		err(2, "sigaction:ALARM");
	}
	if (sigaction(SIGINT, &sa, NULL)) {
		err(2, "sigaction:INTERRUPT");
	}

	/* timer */
	for (size_t i = 0; i < nb_timers; ++i) {
		if (timer_create(CLOCK_REALTIME, NULL, &timerid[i])) {
			warn("timer_create failed for %zu", i);
			continue;
		}
		/* 3 -> TIMER_MAX stored into timerid->oshandle */
		np = malloc(sizeof(struct entry));	/* Insert at the head. */
		np->code = timer_oshandle_np(timerid[i]);
		np->name = names[i];

		SLIST_INSERT_HEAD(&head, np, entries);

		/* Set values and start timer */
		struct itimerspec its;
		its.it_interval.tv_sec = 1 + i * 2;
		its.it_interval.tv_nsec = 0;
		its.it_value.tv_sec = its.it_interval.tv_sec;
		its.it_value.tv_nsec = 0;

		if (timer_settime(timerid[i], 0, &its, NULL)) {
			warn("timer_settime failed for %zu", i);
		}
		printf("Timer %s now created at interval %ld.\n", np->name, its.it_interval.tv_sec);
	}

	printf("waiting...\n");
	for (; !spankme;) {
		pause();
		if (++cols > 79) { 
			cols = 0;
			printf("\n");
		}
	}

	printf("\nbye.\n");
	for (size_t i = 0; i < nb_timers; ++i) {
		timer_delete(timerid[i]);
	}

	while (!SLIST_EMPTY(&head)) {
		np = SLIST_FIRST(&head);
		SLIST_REMOVE_HEAD(&head, entries);
		free(np->name);
		free(np);
	}

	return EXIT_SUCCESS;

}