/*
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 1980, 1988, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <ctype.h>
#include <err.h>
#include <locale.h>
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <unistd.h>

#include <capsicum_helpers.h>

static void doalarm(u_int);
static void usage(void) __dead2;

/*
 * leave [[+]hhmm]
 *
 * Reminds you when you have to leave.
 * Leave prompts for input and goes away if you hit return.
 * It nags you like a mother hen.
 */
int
main(int argc, char **argv)
{
        u_int secs;
        int hours, minutes;
        char c, *cp = NULL;
        struct tm *t;
        time_t now;
        int plusnow, t_12_hour;
        char buf[50];

        if (setlocale(LC_TIME, "") == NULL)
                warn("setlocale");

        caph_cache_tzdata();
        caph_cache_catpages();
        if (caph_limit_stdio() < 0 || caph_enter() < 0)
                err(EXIT_FAILURE, "capsicum");

        if (argc < 2) {
#define MSG1    "When do you have to leave? "
                (void)write(STDOUT_FILENO, MSG1, sizeof(MSG1) - 1);
                cp = fgets(buf, sizeof(buf), stdin);
                if (cp == NULL || *cp == '\n')
                        exit(EXIT_SUCCESS);
        } else if (argc > 2)
                usage();
        else
                cp = argv[1];

        if (*cp == '+') {
                plusnow = 1;
                ++cp;
        } else
                plusnow = 0;

        for (hours = 0; (c = *cp) && c != '\n'; ++cp) {
                if (!isdigit(c))
                        usage();
                hours = hours * 10 + (c - '0');
        }
        minutes = hours % 100;
        hours /= 100;

        if (minutes < 0 || minutes > 59)
                usage();
        if (plusnow)
                secs = hours * 60 * 60 + minutes * 60;
        else {
                (void)time(&now);
                t = localtime(&now);

                if (hours > 23)
                        usage();

                /* Convert tol to 12 hr time (0:00...11:59) */
                if (hours > 11)
                        hours -= 12;

                /* Convert tm to 12 hr time (0:00...11:59) */
                if (t->tm_hour > 11)
                        t_12_hour = t->tm_hour - 12;
                else
                        t_12_hour = t->tm_hour;

                if (hours < t_12_hour ||
                   (hours == t_12_hour && minutes <= t->tm_min))
                        /* Leave time is in the past so we add 12 hrs */
                        hours += 12;

                secs = (hours - t_12_hour) * 60 * 60;
                secs += (minutes - t->tm_min) * 60;
                secs -= now % 60;       /* truncate (now + secs) to min */
        }
        doalarm(secs);
        exit(EXIT_SUCCESS);
}

void
doalarm(u_int secs)
{
        int bother;
        time_t daytime;
        char tb[80];
        int pid;

        if ((pid = fork())) {
                (void)time(&daytime);
                daytime += secs;
                strftime(tb, sizeof(tb), "%+", localtime(&daytime));
                printf("Alarm set for %s. (pid %d)\n", tb, pid);
                exit(EXIT_SUCCESS);
        }
        sleep((u_int)2);                /* let parent print set message */
        if (secs >= 2)
                secs -= 2;

        /*
         * if write fails, we've lost the terminal through someone else
         * causing a vhangup by logging in.
         */
#define FIVEMIN (5 * 60)
#define MSG2    "\07\07You have to leave in 5 minutes.\n"
        if (secs >= FIVEMIN) {
                sleep(secs - FIVEMIN);
                if (write(STDOUT_FILENO, MSG2, sizeof(MSG2) - 1) != sizeof(MSG2) - 1)
                        exit(EXIT_SUCCESS);
                secs = FIVEMIN;
        }

#define ONEMIN  (60)
#define MSG3    "\07\07Just one more minute!\n"
        if (secs >= ONEMIN) {
                sleep(secs - ONEMIN);
                if (write(STDOUT_FILENO, MSG3, sizeof(MSG3) - 1) != sizeof(MSG3) - 1)
                        exit(EXIT_SUCCESS);
        }

#define MSG4    "\07\07Time to leave!\n"
        for (bother = 10; bother--;) {
                sleep((u_int)ONEMIN);
                if (write(STDOUT_FILENO, MSG4, sizeof(MSG4) - 1) != sizeof(MSG4) - 1)
                        exit(EXIT_SUCCESS);
        }

#define MSG5    "\07\07That was the last time I'll tell you.  Bye.\n"
        (void)write(STDOUT_FILENO, MSG5, sizeof(MSG5) - 1);
        exit(EXIT_SUCCESS);
}

static void
usage(void)
{
        fprintf(stderr, "usage: leave [[+]hhmm]\n");
        exit(EXIT_FAILURE);
}