/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 1989, 1993, 1994
 *      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 <sys/types.h>
#include <err.h>
#include <errno.h>
#include <locale.h>
#include <login_cap.h>
#include <langinfo.h>
#include <pwd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>

#include "calendar.h"

#define UTCOFFSET_NOTSET        100     /* Expected between -24 and +24 */
#define LONGITUDE_NOTSET        1000    /* Expected between -360 and +360 */

struct passwd   *pw;
int             doall = 0;
int             debug = 0;
static char     *DEBUG = NULL;
static time_t   f_time = 0;
double          UTCOffset = UTCOFFSET_NOTSET;
int             EastLongitude = LONGITUDE_NOTSET;
#ifdef WITH_ICONV
const char      *outputEncoding = NULL;
#endif

static void     usage(void) __dead2;

int
main(int argc, char *argv[])
{
        int     f_dayAfter = 0;         /* days after current date */
        int     f_dayBefore = 0;        /* days before current date */
        int     Friday = 5;             /* day before weekend */

        int ch;
        struct tm tp1, tp2;

        (void)setlocale(LC_ALL, "");

        while ((ch = getopt(argc, argv, "-A:aB:D:dF:f:l:t:U:W:?")) != -1)
                switch (ch) {
                case '-':               /* backward contemptible */
                case 'a':
                        if (getuid()) {
                                errno = EPERM;
                                err(1, NULL);
                        }
                        doall = 1;
                        break;

                case 'W': /* we don't need no steenking Fridays */
                        Friday = -1;
                        /* FALLTHROUGH */

                case 'A': /* days after current date */
                        f_dayAfter = atoi(optarg);
                        if (f_dayAfter < 0)
                                errx(1, "number of days must be positive");
                        break;

                case 'B': /* days before current date */
                        f_dayBefore = atoi(optarg);
                        if (f_dayBefore < 0)
                                errx(1, "number of days must be positive");
                        break;

                case 'D': /* debug output of sun and moon info */
                        DEBUG = optarg;
                        break;

                case 'd': /* debug output of current date */
                        debug = 1;
                        break;

                case 'F': /* Change the time: When does weekend start? */
                        Friday = atoi(optarg);
                        break;

                case 'f': /* other calendar file */
                        calendarFile = optarg;
                        break;

                case 'l': /* Change longitudal position */
                        EastLongitude = strtol(optarg, NULL, 10);
                        break;

                case 't': /* other date, for tests */
                        f_time = Mktime(optarg);
                        break;

                case 'U': /* Change UTC offset */
                        UTCOffset = strtod(optarg, NULL);
                        break;

                case '?':
                default:
                        usage();
                }

        argc -= optind;
        argv += optind;

        if (argc)
                usage();

        /* use current time */
        if (f_time <= 0)
                (void)time(&f_time);

        /* if not set, determine where I could be */
        {
                if (UTCOffset == UTCOFFSET_NOTSET &&
                    EastLongitude == LONGITUDE_NOTSET) {
                        /* Calculate on difference between here and UTC */
                        time_t t;
                        struct tm tm;
                        long utcoffset, hh, mm, ss;
                        double uo;

                        time(&t);
                        localtime_r(&t, &tm);
                        utcoffset = tm.tm_gmtoff;
                        /* seconds -> hh:mm:ss */
                        hh = utcoffset / SECSPERHOUR;
                        utcoffset %= SECSPERHOUR;
                        mm = utcoffset / SECSPERMINUTE;
                        utcoffset %= SECSPERMINUTE;
                        ss = utcoffset;

                        /* hh:mm:ss -> hh.mmss */
                        uo = mm + (100.0 * (ss / 60.0));
                        uo /=  60.0 / 100.0;
                        uo = hh + uo / 100;

                        UTCOffset = uo;
                        EastLongitude = UTCOffset * 15;
                } else if (UTCOffset == UTCOFFSET_NOTSET) {
                        /* Base on information given */
                        UTCOffset = EastLongitude / 15;
                } else if (EastLongitude == LONGITUDE_NOTSET) {
                        /* Base on information given */
                        EastLongitude = UTCOffset * 15;
                }
        }

        settimes(f_time, f_dayBefore, f_dayAfter, Friday, &tp1, &tp2);
        generatedates(&tp1, &tp2);

        /*
         * FROM now on, we are working in UTC.
         * This will only affect moon and sun related events anyway.
         */
        if (setenv("TZ", "UTC", 1) != 0)
                errx(1, "setenv: %s", strerror(errno));
        tzset();

        if (debug)
                dumpdates();

        if (DEBUG != NULL) {
                dodebug(DEBUG);
                exit(0);
        }

        if (doall)
                while ((pw = getpwent()) != NULL) {
                        pid_t pid;

                        if (chdir(pw->pw_dir) == -1)
                                continue;
                        pid = fork();
                        if (pid < 0)
                                err(1, "fork");
                        if (pid == 0) {
                                login_cap_t *lc;

                                lc = login_getpwclass(pw);
                                if (setusercontext(lc, pw, pw->pw_uid,
                                    LOGIN_SETALL & ~LOGIN_SETLOGIN) != 0)
                                        errx(1, "setusercontext");
                                setenv("HOME", pw->pw_dir, 1);
                                cal();
                                exit(0);
                        }
                }
        else {
#ifdef WITH_ICONV
                /* Save the information about the encoding used in the terminal. */
                outputEncoding = strdup(nl_langinfo(CODESET));
                if (outputEncoding == NULL)
                        errx(1, "cannot allocate memory");
#endif
                cal();
        }
        exit(0);
}


static void __dead2
usage(void)
{

        fprintf(stderr, "%s\n%s\n%s\n",
            "usage: calendar [-A days] [-a] [-B days] [-D sun|moon] [-d]",
            "                [-F friday] [-f calendarfile] [-l longitude]",
            "                [-t dd[.mm[.year]]] [-U utcoffset] [-W days]"
            );
        exit(1);
}