/* See LICENSE file for copyright and license details. */
#include "common.h"
#include <sys/timex.h>

USAGE("[-u | -v | -w] [-s2]");


#include "large.h"


static volatile sig_atomic_t caught_sigterm = 0;
static volatile sig_atomic_t caught_sigwinch = 1;
static volatile sig_atomic_t caught_sigio = 1;
static int with_small = 0;
static int with_quad = 0;
static const char *week_fmt = "%V";

static const char **large_digits[] = {
	large_0, large_1, large_2, large_3, large_4,
	large_5, large_6, large_7, large_8, large_9
};

static const char **small_digits[] = {
	small_0, small_1, small_2, small_3, small_4,
	small_5, small_6, small_7, small_8, small_9
};



static void
sigterm(int signo)
{
	caught_sigterm = 1;
	(void) signo;
}

static void
sigwinch(int signo)
{
	caught_sigwinch = 1;
	(void) signo;
}

static void
sigio(int signo)
{
	caught_sigio = 1;
	(void) signo;
}


static void
print_time(const char ***str, int left, size_t height)
{
	size_t r, c;

	for (r = 0; r < height; r++) {
		printf("%*.s", left, "");
		for (c = 0; str[c]; c++)
			fprintf(stdout, "%s", str[c][r]);
		fprintf(stdout, "\033[K\n");
	}
}


static int
display_clock(int timerfd)
{
	const char *months = "JanFebMarAprMajJunJulAugSepOctNovDec";
	const char *weekdays = "SunMonTueWedThuFriSat";
	const char **digits[9];
	int r, leap_insert, x = 0, y = 0, was_quad = 0, len1, len2, len3, width;
	uint64_t _overrun;
	struct winsize winsize;
	struct tm *now;
	struct timex timex;
	char line1[sizeof(int) * 3 + sizeof("+-(00)aaa-00")];
	char line2[sizeof("aaa, week , ") + sizeof(int) * 3 + 32];
	char line3[sizeof("@(+1)") + sizeof(uintmax_t) * 3];
	char week[sizeof(int) * 3], c;
	ssize_t rd;

	memset(&timex, 0, sizeof(timex));
	digits[8] = NULL;

	while (!caught_sigterm) {
		if (caught_sigwinch) {
			if (ioctl(STDOUT_FILENO, (unsigned long)TIOCGWINSZ, &winsize) < 0) {
				if (errno == EINTR)
					continue;
				goto fail;
			}
			caught_sigwinch = 0;
			y = winsize.ws_row;
			x = winsize.ws_col;
			if (was_quad) {
				was_quad = 0;
				for (r = 0; r < y; r++)
					printf("%s\033#5", r ? "\n" : "\033[H");
			}
		}

		if (caught_sigio) {
			caught_sigio = 0;
			for (;;) {
				rd = read(STDIN_FILENO, &c, 1);
				if (rd <= 0) {
					if (!rd)
						goto out;
					if (errno == EAGAIN)
						break;
					if (errno == EINTR)
						continue;
					goto fail;
				}
				if (c == 'q')
					goto out;
			}
		}

		leap_insert = 0;
		r = adjtimex(&timex);
		if (r == -1)
			goto fail;
		if (timex.time.tv_sec % (24 * 60 * 60) == 0) {
			if (r == TIME_INS) {
				timex.time.tv_sec -= 1;
				now = localtime(&timex.time.tv_sec);
				if (!now)
					goto fail;
				now->tm_sec += leap_insert = 1;
			} else {
				timex.time.tv_sec += (r == TIME_DEL);
				now = localtime(&timex.time.tv_sec);
				if (!now)
					goto fail;
			}
		} else {
			now = localtime(&timex.time.tv_sec);
			if (!now)
				goto fail;
			if (r == TIME_OOP)
				now->tm_sec += leap_insert = 1;
		}

		strftime(week, sizeof(week), week_fmt, now);
		len1 = snprintf(line1, sizeof(line1), "%i-(%02i)%.3s-%02i", now->tm_year + 1900,
		                now->tm_mon + 1, &months[(size_t)now->tm_mon % 12 * 3], now->tm_mday);
		len2 = snprintf(line2, sizeof(line2), "%.3s, week %s, %s",
		                &weekdays[(size_t)now->tm_mday % 7 * 3], week, tzname[now->tm_isdst]);
		len3 = snprintf(line3, sizeof(line3), "(@%ji%s)", (intmax_t)timex.time.tv_sec, leap_insert ? "+1" : "");

		printf("\033[H");

		if (x >= 6 * LARGE_XD + 2 * LARGE_XC && y > LARGE_Y + 1) {
			if (y > LARGE_Y + 6)
				printf("\033[K\n");
			digits[0] = large_digits[now->tm_hour / 10];
			digits[1] = large_digits[now->tm_hour % 10];
			digits[2] = large_colon;
			digits[3] = large_digits[now->tm_min / 10];
			digits[4] = large_digits[now->tm_min % 10];
			digits[5] = large_colon;
			digits[6] = large_digits[now->tm_sec / 10];
			digits[7] = large_digits[now->tm_sec % 10];
			width = 6 * LARGE_XD + 2 * LARGE_XC;
			print_time(digits, (x - width) / 2, LARGE_Y);
			printf("\033[K\n");
			r = LARGE_Y + 1;
		} else if (with_small && x >= 6 * SMALL_XD + 2 * SMALL_XC && y > SMALL_Y + 1) {
			if (y > SMALL_Y + 6)
				printf("\033[K\n");
			digits[0] = small_digits[now->tm_hour / 10];
			digits[1] = small_digits[now->tm_hour % 10];
			digits[2] = small_colon;
			digits[3] = small_digits[now->tm_min / 10];
			digits[4] = small_digits[now->tm_min % 10];
			digits[5] = small_colon;
			digits[6] = small_digits[now->tm_sec / 10];
			digits[7] = small_digits[now->tm_sec % 10];
			width = 6 * SMALL_XD + 2 * SMALL_XC;
			print_time(digits, (x - width) / 2, SMALL_Y);
			printf("\033[K\n");
			r = SMALL_Y + 1;
		} else if (with_quad && x > 8 * 2 && y > 2) {
			if (y > 6)
				printf("\033[K\n");
			printf("\033#3%*.s%02i:%02i:%02i\033[K\n", (x / 2 - 8) / 2, "", now->tm_hour, now->tm_min, now->tm_sec);
			printf("\033#4%*.s%02i:%02i:%02i\033[K\n", (x / 2 - 8) / 2, "", now->tm_hour, now->tm_min, now->tm_sec);
			printf("\033#5");
			was_quad = 1;
			width = 8 * 2;
			r = 2;
		} else {
			printf("%*.s%02i:%02i:%02i\033[K", (x - 8) / 2, "", now->tm_hour, now->tm_min, now->tm_sec);
			if (y > 1)
				printf("\n");
			width = 8;
			r = 1;
		}

		if (len1 + len2 + 2 < width && len3 < width && r + 1 < y) {
			printf("%*.s%s, %s\033[K\n", (x - len1 - len2 - 2) / 2, "", line1, line2);
			printf("%*.s%s\033[K", (x - len3) / 2, "", line3);
		} else if (len1 + len2 + len3 + 3 < width && r < y) {
			printf("%*.s%s, %s %s\033[K", (x - len1 - len2 - len3 - 3) / 2, "", line1, line2, line3);
		} else if (len1 + len2 + 2 < width && len3 < width && r + 1 == y) {
			printf("%*.s%s, %s\033[K", (x - len1 - len2 - 2) / 2, "", line1, line2);
		} else {
			if (len1 < x && r < y) {
				printf("%*.s%s\033[K", (x - len1) / 2, "", line1);
				r += 1;
				if (r < y)
					printf("\n");
			}
			if (len2 < x && r < y) {
				printf("%*.s%s\033[K", (x - len2) / 2, "", line2);
				r += 1;
				if (r < y)
					printf("\n");
			}
			if (len3 < x && r < y) {
				printf("%*.s%s\033[K", (x - len3) / 2, "", line3);
				r += 1;
			}
		}

		printf("\033[J");
		fflush(stdout);

		if (read(timerfd, &_overrun, sizeof(_overrun)) < 0)
			if (errno != EINTR)
				goto fail;
	}

out:
	return 0;

fail:
	return -1;
}


int
main(int argc, char *argv[])
{
	int timerfd = -1, tcset = 0, old_flags = -1, old_sig = 0, owner_set = 0;
	struct itimerspec itimerspec;
	struct sigaction sigact;
	struct termios stty, saved_stty;
	struct f_owner_ex old_owner, new_owner;

	ARGBEGIN {
	case '2':
		with_quad = 1;
		break;
	case 's':
		with_small = 1;
		break;
	case 'u':
		week_fmt = "%U";
		break;
	case 'v':
		week_fmt = "%V";
		break;
	case 'w':
		week_fmt = "%W";
		break;
	default:
		usage();
	} ARGEND;

	if (argc)
		usage();

	tzset();

	fprintf(stdout, "\033[?1049h\033[?25l");

	if (clock_gettime(CLOCK_REALTIME, &itimerspec.it_value))
		goto fail;
	itimerspec.it_interval.tv_sec = 1;
	itimerspec.it_interval.tv_nsec = 0;
	itimerspec.it_value.tv_sec += 1;
	itimerspec.it_value.tv_nsec = 0;
	timerfd = timerfd_create(CLOCK_REALTIME, 0);
	if (timerfd < 0)
		goto fail;
	if (timerfd_settime(timerfd, TFD_TIMER_ABSTIME, &itimerspec, NULL))
		goto fail;

	memset(&sigact, 0, sizeof(sigact));

	sigact.sa_handler = sigterm;
	sigaction(SIGTERM, &sigact, NULL);
	sigaction(SIGQUIT, &sigact, NULL);
	sigaction(SIGINT, &sigact, NULL);

	sigact.sa_handler = sigwinch;
	sigaction(SIGWINCH, &sigact, NULL);

	sigact.sa_handler = sigio;
	sigaction(SIGIO, &sigact, NULL);
	sigaction(SIGURG, &sigact, NULL);

	if (fcntl(STDIN_FILENO, F_GETOWN_EX, &old_owner))
		goto fail;
	memset(&new_owner, 0, sizeof(new_owner));
	new_owner.type = F_OWNER_PID;
	new_owner.pid = getpid();
	if (fcntl(STDIN_FILENO, F_SETOWN_EX, &new_owner))
		goto fail;
	owner_set = 1;
	old_flags = fcntl(STDIN_FILENO, F_GETFL);
	fcntl(STDIN_FILENO, F_SETFL, old_flags | FASYNC | O_NONBLOCK);
	fcntl(STDIN_FILENO, F_GETSIG, &old_sig);
	if (old_sig)
		fcntl(STDIN_FILENO, F_SETSIG, 0);

	if (!tcgetattr(STDIN_FILENO, &stty)) {
		saved_stty = stty;
		stty.c_lflag &= (tcflag_t)~(ECHO | ICANON);
		tcsetattr(STDIN_FILENO, TCSAFLUSH, &stty);
		tcset = 1;
	}

	if (display_clock(timerfd))
		goto fail;

	fprintf(stdout, "\033[?25h\n\033[?1049l");
	fflush(stdout);
	close(timerfd);
	fcntl(STDIN_FILENO, F_SETOWN_EX, &old_owner);
	fcntl(STDIN_FILENO, F_SETFL, old_flags);
	fcntl(STDIN_FILENO, F_SETSIG, old_sig);
	tcsetattr(STDIN_FILENO, TCSAFLUSH, &saved_stty);
	return 0;

fail:
	perror(argv0 ? argv0 : "clock");
	fprintf(stdout, "\033[?25h\n\033[?1049l");
	fflush(stdout);
	if (owner_set)
		fcntl(STDIN_FILENO, F_SETOWN_EX, &old_owner);
	if (old_flags != -1)
		fcntl(STDIN_FILENO, F_SETFL, old_flags);
	if (old_sig)
		fcntl(STDIN_FILENO, F_SETSIG, old_sig);
	if (tcset)
		tcsetattr(STDIN_FILENO, TCSAFLUSH, &saved_stty);
	if (timerfd >= 0)
		close(timerfd);
	return 1;
}