/*
 * Copyright 1996 Massachusetts Institute of Technology
 *
 * Permission to use, copy, modify, and distribute this software and
 * its documentation for any purpose and without fee is hereby
 * granted, provided that both the above copyright notice and this
 * permission notice appear in all copies, that both the above
 * copyright notice and this permission notice appear in all
 * supporting documentation, and that the name of M.I.T. not be used
 * in advertising or publicity pertaining to distribution of the
 * software without specific, written prior permission.  M.I.T. makes
 * no representations about the suitability of this software for any
 * purpose.  It is provided "as is" without express or implied
 * warranty.
 * 
 * THIS SOFTWARE IS PROVIDED BY M.I.T. ``AS IS''.  M.I.T. DISCLAIMS
 * ALL EXPRESS OR IMPLIED WARRANTIES WITH REGARD TO THIS SOFTWARE,
 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT
 * SHALL M.I.T. 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.
 */

/*
 * Second attempt at a `tzmenu' program, using the separate description
 * files provided in newer tzdata releases.
 */

#ifndef lint
static const char rcsid[] =
	"$Id: tzsetup.c,v 1.10 1998/01/10 15:55:11 steve Exp $";
#endif /* not lint */

#include <sys/types.h>
#include <dialog.h>
#include <err.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include <sys/fcntl.h>
#include <sys/queue.h>
#include <sys/stat.h>

#include "paths.h"

static int reallydoit = 1;

static int continent_country_menu(dialogMenuItem *);
static int set_zone_multi(dialogMenuItem *);
static int set_zone_whole_country(dialogMenuItem *);
static int set_zone_menu(dialogMenuItem *);

struct continent {
	dialogMenuItem *menu;
	int nitems;
	int ch;
	int sc;
};

static struct continent africa, america, antarctica, arctic, asia, atlantic;
static struct continent australia, europe, indian, pacific;

static struct continent_names {
	char *name;
	struct continent *continent;
} continent_names[] = {
	{ "Africa", &africa }, { "America", &america },
	{ "Antarctica", &antarctica }, { "Arctic", &arctic }, 
	{ "Asia", &asia },
	{ "Atlantic", &atlantic }, { "Australia", &australia },
	{ "Europe", &europe }, { "Indian", &indian }, { "Pacific", &pacific }
};

static dialogMenuItem continents[] = {
	{ "1", "Africa", 0, continent_country_menu, 0, &africa },
	{ "2", "America -- North and South", 0, continent_country_menu, 0, 
		  &america },
	{ "3", "Antarctica", 0, continent_country_menu, 0, &antarctica },
	{ "4", "Arctic Ocean", 0, continent_country_menu, 0, &arctic },
	{ "5", "Asia", 0, continent_country_menu, 0, &asia },
	{ "6", "Atlantic Ocean", 0, continent_country_menu, 0, &atlantic },
	{ "7", "Australia", 0, continent_country_menu, 0, &australia },
	{ "8", "Europe", 0, continent_country_menu, 0, &europe },
	{ "9", "Indian Ocean", 0, continent_country_menu, 0, &indian },
	{ "0", "Pacific Ocean", 0, continent_country_menu, 0, &pacific }
};
#define NCONTINENTS ((sizeof continents)/(sizeof continents[0]))
#define OCEANP(x) ((x) == 3 || (x) == 5 || (x) == 8 || (x) == 9)

static int
continent_country_menu(dialogMenuItem *continent)
{
	int rv;
	struct continent *contp = continent->data;
	char title[256];
	int isocean = OCEANP(continent - continents);
	int menulen;

	/* Short cut -- if there's only one country, don't post a menu. */
	if (contp->nitems == 1) {
		return set_zone_menu(&contp->menu[0]);
	}

	/* It's amazing how much good grammar really matters... */
	if (!isocean)
		snprintf(title, sizeof title, "Countries in %s", 
			 continent->title);
	else 
		snprintf(title, sizeof title, "Islands and groups in the %s",
			 continent->title);

	menulen = contp->nitems < 16 ? contp->nitems : 16;
	rv = dialog_menu(title, (isocean ? "Select an island or group"
                                 : "Select a country"), -1, -1, menulen,
			 -contp->nitems, contp->menu, 0, &contp->ch,
			 &contp->sc);
	if (rv == 0)
		return DITEM_LEAVE_MENU;
	return DITEM_RECREATE;
}

static struct continent *
find_continent(const char *name)
{
	int i;

	for (i = 0; i < NCONTINENTS; i++) {
		if (strcmp(name, continent_names[i].name) == 0)
			return continent_names[i].continent;
	}
	return 0;
}

struct country {
	char *name;
	char *tlc;
	int nzones;
	char *filename;		/* use iff nzones < 0 */
	struct continent *continent; /* use iff nzones < 0 */
	TAILQ_HEAD(, zone) zones; /* use iff nzones > 0 */
	dialogMenuItem *submenu; /* use iff nzones > 0 */
};

struct zone {
	TAILQ_ENTRY(zone) link;
	char *descr;
	char *filename;
	struct continent *continent;
};

/*
 * This is the easiest organization... we use ISO 3166 country codes,
 * of the two-letter variety, so we just size this array to suit.
 * Beats worrying about dynamic allocation.
 */
#define NCOUNTRIES	(26*26)
static struct country countries[NCOUNTRIES];
#define CODE2INT(s) ((s[0] - 'A') * 26 + (s[1] - 'A'))

/*
 * Read the ISO 3166 country code database in _PATH_ISO3166
 * (/usr/share/misc/iso3166).  On error, exit via err(3).
 */
static void
read_iso3166_table(void)
{
	FILE *fp;
	char *s, *t, *name;
	size_t len;
	int lineno;
	struct country *cp;

	fp = fopen(_PATH_ISO3166, "r");
	if (!fp)
		err(1, _PATH_ISO3166);
	lineno = 0;

	while ((s = fgetln(fp, &len)) != 0) {
		lineno++;
		if (s[len - 1] != '\n')
			errx(1, _PATH_ISO3166 ":%d: invalid format", lineno);
		s[len - 1] = '\0';
		if (s[0] == '#' || strspn(s, " \t") == len - 1)
			continue;

		/* Isolate the two-letter code. */
		t = strsep(&s, "\t");
		if (t == 0 || strlen(t) != 2)
			errx(1, _PATH_ISO3166 ":%d: invalid format", lineno);
		if (t[0] < 'A' || t[0] > 'Z' || t[1] < 'A' || t[1] > 'Z')
			errx(1, _PATH_ISO3166 ":%d: invalid code `%s'",
			     lineno, t);

		/* Now skip past the three-letter and numeric codes. */
		name = strsep(&s, "\t"); /* 3-let */
		if (name == 0 || strlen(name) != 3)
			errx(1, _PATH_ISO3166 ":%d: invalid format", lineno);
		name = strsep(&s, "\t"); /* numeric */
		if (name == 0 || strlen(name) != 3)
			errx(1, _PATH_ISO3166 ":%d: invalid format", lineno);

		name = s;

		cp = &countries[CODE2INT(t)];
		if (cp->name)
			errx(1, _PATH_ISO3166 
			     ":%d: country code `%s' multiply defined: %s",
			     lineno, t, cp->name);
		cp->name = strdup(name);
		cp->tlc = strdup(t);
	}

	fclose(fp);
}

static void
add_zone_to_country(int lineno, const char *tlc, const char *descr,
		    const char *file, struct continent *cont)
{
	struct zone *zp;
	struct country *cp;

	if (tlc[0] < 'A' || tlc[0] > 'Z' || tlc[1] < 'A' || tlc[1] > 'Z')
		errx(1, _PATH_ZONETAB ":%d: country code `%s' invalid",
		     lineno, tlc);
	
	cp = &countries[CODE2INT(tlc)];
	if (cp->name == 0)
		errx(1, _PATH_ZONETAB ":%d: country code `%s' unknown",
		     lineno, tlc);

	if (descr) {
		if (cp->nzones < 0)
			errx(1, _PATH_ZONETAB 
			     ":%d: conflicting zone definition", lineno);

		zp = malloc(sizeof *zp);
		if (zp == 0)
			err(1, "malloc(%lu)", (unsigned long)sizeof *zp);
		
		if (cp->nzones == 0)
			TAILQ_INIT(&cp->zones);

		zp->descr = strdup(descr);
		zp->filename = strdup(file);
		zp->continent = cont;
		TAILQ_INSERT_TAIL(&cp->zones, zp, link);
		cp->nzones++;
	} else {
		if (cp->nzones > 0)
			errx(1, _PATH_ZONETAB 
			     ":%d: zone must have description", lineno);
		if (cp->nzones < 0)
			errx(1, _PATH_ZONETAB
			     ":%d: zone multiply defined", lineno);
		cp->nzones = -1;
		cp->filename = strdup(file);
		cp->continent = cont;
	}
}

/*
 * This comparison function intentionally sorts all of the null-named
 * ``countries''---i.e., the codes that don't correspond to a real
 * country---to the end.  Everything else is lexical by country name.
 */
static int
compare_countries(const void *xa, const void *xb)
{
	const struct country *a = xa, *b = xb;

	if (a->name == 0 && b->name == 0)
		return 0;
	if (a->name == 0 && b->name != 0)
		return 1;
	if (b->name == 0)
		return -1;

	return strcmp(a->name, b->name);
}

/*
 * This must be done AFTER all zone descriptions are read, since it breaks
 * CODE2INT().
 */
static void
sort_countries(void)
{
	qsort(countries, NCOUNTRIES, sizeof countries[0], compare_countries);
}

static void
read_zones(void)
{
	FILE *fp;
	char *line;
	size_t len;
	int lineno;
	char *tlc, *coord, *file, *descr, *p;
	char contbuf[16];
	struct continent *cont;

	fp = fopen(_PATH_ZONETAB, "r");
	if (!fp)
		err(1, _PATH_ZONETAB);
	lineno = 0;

	while ((line = fgetln(fp, &len)) != 0) {
		lineno++;
		if (line[len - 1] != '\n')
			errx(1, _PATH_ZONETAB ":%d: invalid format", lineno);
		line[len - 1] = '\0';
		if (line[0] == '#')
			continue;

		tlc = strsep(&line, "\t");
		if (strlen(tlc) != 2)
			errx(1, _PATH_ZONETAB ":%d: invalid country code `%s'",
			     lineno, tlc);
		coord = strsep(&line, "\t");
		file = strsep(&line, "\t");
		p = strchr(file, '/');
		if (p == 0)
			errx(1, _PATH_ZONETAB ":%d: invalid zone name `%s'",
			     lineno, file);
		contbuf[0] = '\0';
		strncat(contbuf, file, p - file);
		cont = find_continent(contbuf);
		if (!cont)
			errx(1, _PATH_ZONETAB ":%d: invalid region `%s'",
			     lineno, contbuf);

		descr = (line && *line) ? line : 0;

		add_zone_to_country(lineno, tlc, descr, file, cont);
	}
	fclose(fp);
}

static void
make_menus(void)
{
	struct country *cp;
	struct zone *zp, *zp2;
	struct continent *cont;
	dialogMenuItem *dmi;
	int i;

	/*
	 * First, count up all the countries in each continent/ocean.
	 * Be careful to count those countries which have multiple zones
	 * only once for each.  NB: some countries are in multiple
	 * continents/oceans.
	 */
	for (cp = countries; cp->name; cp++) {
		if (cp->nzones == 0)
			continue;
		if (cp->nzones < 0) {
			cp->continent->nitems++;
		} else {
			for (zp = cp->zones.tqh_first; zp; 
			     zp = zp->link.tqe_next) {
				cont = zp->continent;
				for (zp2 = cp->zones.tqh_first;
				     zp2->continent != cont;
				     zp2 = zp2->link.tqe_next)
					;
				if (zp2 == zp)
					zp->continent->nitems++;
			}
		}
	}

	/*
	 * Now allocate memory for the country menus.  We set
	 * nitems back to zero so that we can use it for counting
	 * again when we actually build the menus.
	 */
	for (i = 0; i < NCONTINENTS; i++) {
		continent_names[i].continent->menu =
			malloc(sizeof(dialogMenuItem) *
			       continent_names[i].continent->nitems);
		if (continent_names[i].continent->menu == 0)
			err(1, "malloc for continent menu");
		continent_names[i].continent->nitems = 0;
	}

	/*
	 * Now that memory is allocated, create the menu items for
	 * each continent.  For multiple-zone countries, also create
	 * the country's zone submenu.
	 */
	for (cp = countries; cp->name; cp++) {
		if (cp->nzones == 0)
			continue;
		if (cp->nzones < 0) {
			dmi = &cp->continent->menu[cp->continent->nitems];
			memset(dmi, 0, sizeof *dmi);
			asprintf(&dmi->prompt, "%d", 
				 ++cp->continent->nitems);
			dmi->title = cp->name;
			dmi->checked = 0;
			dmi->fire = set_zone_whole_country;
			dmi->selected = 0;
			dmi->data = cp;
		} else {
			cp->submenu = malloc(cp->nzones * sizeof *dmi);
			if (cp->submenu == 0)
				err(1, "malloc for submenu");
			cp->nzones = 0;
			for (zp = cp->zones.tqh_first; zp; 
			     zp = zp->link.tqe_next) {
				cont = zp->continent;
				dmi = &cp->submenu[cp->nzones];
				memset(dmi, 0, sizeof *dmi);
				asprintf(&dmi->prompt, "%d",
					 ++cp->nzones);
				dmi->title = zp->descr;
				dmi->checked = 0;
				dmi->fire = set_zone_multi;
				dmi->selected = 0;
				dmi->data = zp;

				for (zp2 = cp->zones.tqh_first;
				     zp2->continent != cont;
				     zp2 = zp2->link.tqe_next)
					;
				if (zp2 != zp)
					continue;

				dmi = &cont->menu[cont->nitems];
				memset(dmi, 0, sizeof *dmi);
				asprintf(&dmi->prompt, "%d", ++cont->nitems);
				dmi->title = cp->name;
				dmi->checked = 0;
				dmi->fire = set_zone_menu;
				dmi->selected = 0;
				dmi->data = cp;
			}
		}
	}
}

static int
set_zone_menu(dialogMenuItem *dmi)
{
	int rv;
	char buf[256];
	struct country *cp = dmi->data;
	int menulen;

	snprintf(buf, sizeof buf, "%s Time Zones", cp->name);
	menulen = cp->nzones < 16 ? cp->nzones : 16;
	rv = dialog_menu(buf, "Select a zone which observes the same time as "
			 "your locality.", -1, -1, menulen, -cp->nzones,
			 cp->submenu, 0, 0, 0);
	if (rv != 0)
		return DITEM_RECREATE;
	return DITEM_LEAVE_MENU;
}

static int
install_zone_file(const char *filename)
{
	struct stat sb;
	int fd1, fd2;
	int copymode;
	char *msg;
	ssize_t len;
	char buf[1024];

	if (lstat(_PATH_LOCALTIME, &sb) < 0)
		/* Nothing there yet... */
		copymode = 1;
	else if(S_ISLNK(sb.st_mode))
		copymode = 0;
	else
		copymode = 1;

#ifdef VERBOSE
	if (copymode)
		asprintf(&msg, "Copying %s to " _PATH_LOCALTIME, filename);
	else
		asprintf(&msg, "Creating symbolic link " _PATH_LOCALTIME
			 " to %s", filename);

	dialog_notify(msg);
	free(msg);
#endif

	if (reallydoit) {
		if (copymode) {
			fd1 = open(filename, O_RDONLY, 0);
			if (fd1 < 0) {
				asprintf(&msg, "Could not open %s: %s",
					 filename, strerror(errno));
				dialog_mesgbox("Error", msg, 8, 72);
				free(msg);
				return DITEM_FAILURE | DITEM_RECREATE;
			}

			unlink(_PATH_LOCALTIME);
			fd2 = open(_PATH_LOCALTIME, 
				   O_CREAT | O_EXCL | O_WRONLY,
				   0444);
			if (fd2 < 0) {
				asprintf(&msg, "Could not open "
					 _PATH_LOCALTIME ": %s", 
					 strerror(errno));
				dialog_mesgbox("Error", msg, 8, 72);
				free(msg);
				return DITEM_FAILURE | DITEM_RECREATE;
			}

			while ((len = read(fd1, buf, sizeof buf)) > 0)
				len = write(fd2, buf, len);

			if (len == -1) {
				asprintf(&msg, "Error copying %s to "
					 _PATH_LOCALTIME ": %s",
					 strerror(errno));
				dialog_mesgbox("Error", msg, 8, 72);
				free(msg);
				/* Better to leave none than a corrupt one. */
				unlink(_PATH_LOCALTIME);
				return DITEM_FAILURE | DITEM_RECREATE;
			}
			close(fd1);
			close(fd2);
		} else {
			if (access(filename, R_OK) != 0) {
				asprintf(&msg, "Cannot access %s: %s",
					 filename, strerror(errno));
				dialog_mesgbox("Error", msg, 8, 72);
				free(msg);
				return DITEM_FAILURE | DITEM_RECREATE;
			}
			unlink(_PATH_LOCALTIME);
			if (symlink(filename, _PATH_LOCALTIME) < 0) {
				asprintf(&msg, "Cannot create symbolic link "
					 _PATH_LOCALTIME " to %s: %s",
					 filename, strerror(errno));
				dialog_mesgbox("Error", msg, 8, 72);
				free(msg);
				return DITEM_FAILURE | DITEM_RECREATE;
			}
		}
	}

#ifdef VERBOSE
	if (copymode)
		asprintf(&msg, "Copied timezone file from %s to " 
			 _PATH_LOCALTIME, filename);
	else
		asprintf(&msg, "Created symbolic link from " _PATH_LOCALTIME
			 " to %s", filename);

	dialog_mesgbox("Done", msg, 8, 72);
	free(msg);
#endif
	return DITEM_LEAVE_MENU;
}

static int
confirm_zone(const char *filename)
{
	char *msg;
	struct tm *tm;
	time_t t = time(0);
	int rv;
	
	setenv("TZ", filename, 1);
	tzset();
	tm = localtime(&t);

	asprintf(&msg, "Does the abbreviation `%s' look reasonable?",
		 tm->tm_zone);
	rv = !dialog_yesno("Confirmation", msg, 4, 72);
	free(msg);
	return rv;
}

static int
set_zone_multi(dialogMenuItem *dmi)
{
	char *fn;
	struct zone *zp = dmi->data;
	int rv;

	if (!confirm_zone(zp->filename))
		return DITEM_FAILURE | DITEM_RECREATE;

	asprintf(&fn, "%s/%s", _PATH_ZONEINFO, zp->filename);
	rv = install_zone_file(fn);
	free(fn);
	return rv;
}

static int
set_zone_whole_country(dialogMenuItem *dmi)
{
	char *fn;
	struct country *cp = dmi->data;
	int rv;

	if (!confirm_zone(cp->filename))
		return DITEM_FAILURE | DITEM_RECREATE;

	asprintf(&fn, "%s/%s", _PATH_ZONEINFO, cp->filename);
	rv = install_zone_file(fn);
	free(fn);
	return rv;
}

static void
usage()
{
	fprintf(stderr, "usage: tzsetup [-n]\n");
	exit(1);
}

int
main(int argc, char **argv)
{
	int c, fd;

	while ((c = getopt(argc, argv, "n")) != -1) {
		switch(c) {
		case 'n':
			reallydoit = 0;
			break;

		default:
			usage();
		}
	}

	if (optind != argc)
		usage();

	read_iso3166_table();
	read_zones();
	sort_countries();
	make_menus();

	init_dialog();
	if (!dialog_yesno("Select local or UTC (Greenwich Mean Time) clock",
			  "Is this machine's CMOS clock set to UTC?  If it is set to local time,\n"
			  "please choose NO here!", 7, 72)) {
		if (reallydoit)
			unlink(_PATH_WALL_CMOS_CLOCK);
	} else {
		if (reallydoit) {
			fd = open(_PATH_WALL_CMOS_CLOCK,
				  O_WRONLY|O_CREAT|O_TRUNC, 0666);
			if (fd < 0)
				err(1, "create %s", _PATH_WALL_CMOS_CLOCK);
			close(fd);
		}
	}
	dialog_clear_norefresh();
	dialog_menu("Time Zone Selector", "Select a region", -1, -1, 
		    NCONTINENTS, -NCONTINENTS, continents, 0, NULL, NULL);
	dialog_clear();
	end_dialog();
	return 0;
}