dialog-tzselect

#!/usr/bin/ksh
#
# Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
# Copyright 2021 OmniOS Community Edition (OmniOSce) Association.
#
# Ask the user about the time zone, and place the resulting TZ in a file
# whose name is specified in the first argument.

# Contributed by Paul Eggert

. /kayak/lib/dialog.sh

output="${1:?Output}"

AWK=/usr/bin/nawk
GREP=/usr/bin/grep
EXPR=/usr/bin/expr
SORT=/usr/bin/sort
PRINTF=/usr/bin/printf
DATE=/usr/bin/date

TZDIR=/usr/share/lib/zoneinfo

# Messages
ERR_NO_SETUP="%s: time zone files are not set up correctly"
INFO_LOCATION="Please identify a location so that time zone rules \
can be set correctly."
INFO_SELECT_CONT="Please select a continent or ocean."
INFO_POSIX="none - I want to specify the time zone using the POSIX \
TZ format."
WARN_ENTER_NUM="Please enter a number in range."
INFO_ENTER_POSIX="Please enter the desired value of the TZ environment \
variable."
INFO_POSIX_EX="For example, GST-10 is a zone named GST that is 10 hours \
ahead (east) of UTC."
ERR_INV_POSIX="\`%s\' is not a conforming POSIX time zone string."
INFO_SELECT_CNTRY="Please select a country or region."
INFO_SELECT_TZ="Please select one of the following time zone regions."
INFO_EXTRA1="Local time is now:       %s"
INFO_EXTRA2="Universal Time is now:   %s"
INFO_INFO="The following information has been given:"
INFO_TZ="Therefore TZ='%s' will be used."
INFO_OK="Is the above information OK?"

# Make sure the tables are readable.
TZ_CONTINENT_TABLE=$TZDIR/tab/continent.tab
TZ_COUNTRY_TABLE=$TZDIR/tab/country.tab
TZ_ZONE_TABLE=$TZDIR/tab/zone_sun.tab
for f in $TZ_COUNTRY_TABLE $TZ_ZONE_TABLE; do
	<$f || {
		$PRINTF >&2 "$ERR_NO_SETUP\n" $0
		exit 1
	}
done

newline='
'
IFS=$newline

function get_continent {
	dialog \
		--colors \
		--title "$INFO_LOCATION" \
		--no-ok \
		--no-tags \
		--no-lines \
		--nocancel \
		--default-item UTC \
		--menu "\n$INFO_SELECT_CONT\n\Zn" \
		20 0 12 \
		Africa Africa \
		America Americas \
		Antarctica Antarctica \
		Arctic "Arctic Ocean" \
		Asia Asia \
		Atlantic "Atlantic Ocean" \
		Australia Australia \
		Europe Europe \
		Pacific "Pacific Ocean" \
		Indian "Indian Ocean" \
		UTC UTC \
		none "$INFO_POSIX" \
		2> $tmpf
	stat=$?
	[ $stat -eq 0 ] || return 1
	continent="`cat $tmpf`"
	rm -f $tmpf
	return 0
}

function get_posix_tz {
	# Ask the user for a POSIX TZ string. Check that it conforms.
	dialog \
		--title "$INFO_ENTER_POSIX" \
		--colors \
		--inputbox "\n$INFO_POSIX_EX\n\Zn" \
		12 69 "" 2> $tmpf
	[ $? -ne 0 ] && continue 2
	TZ="`cat $tmpf`"
	rm -f $tmpf

	LC_ALL=C $AWK -v TZ="$TZ" 'BEGIN {
		tzname = "[^-+,0-9][^-+,0-9][^-+,0-9]+"
		time = "[0-2]?[0-9](:[0-5][0-9](:[0-5][0-9])?)?"
		offset = "[-+]?" time
		date = "(J?[0-9]+|M[0-9]+\.[0-9]+\.[0-9]+)"
		datetime = "," date "(/" time ")?"
		tzpattern = "^(:.*|" tzname offset "(" tzname \
		  "(" offset ")?(" datetime datetime ")?)?)$"
		if (TZ ~ tzpattern) exit 1
		exit 0
	}'
	if [ $? -ne 0 ]; then
		d_msg $($PRINTF "$ERR_INV_POSIX" "$TZ")
		return 1
	fi
	TZ_for_date=$TZ
	return 0
}

function get_country {
	# Get list of names of countries in the continent or ocean.
	countries=$($AWK -F'\t' \
	    -v continent="$continent" \
	    -v TZ_COUNTRY_TABLE="$TZ_COUNTRY_TABLE" \
	    '
		/^#/ { next }
		$3 ~ ("^" continent "/") {
			if (!cc_seen[$1]++) cc_list[++ccs] = $1
		}
		END {
			while (getline <TZ_COUNTRY_TABLE) {
				if ($0 !~ /^#/) cc_name[$1] = $2
			}
			for (i = 1; i <= ccs; i++) {
				country = cc_list[i]
				if (cc_name[country]) {
				  country = cc_name[country]
				}
				print country
			}
		}
	' < $TZ_ZONE_TABLE | $SORT -f)

	# i18n country names
	c=0
	set -A icountry
	unset args; set -a args
	for country in $countries; do
		icountry[c]=$country
		ocountry[c]="$country"
		args+=("$country" "${icountry[$c]}")
		((c = c + 1))
	done

	if [[ $countries == *"$newline"* ]]; then
		# If there's more than one country, ask the user which one.
		dialog \
			--colors \
			--title "$INFO_SELECT_CNTRY" \
			--no-ok \
			--no-tags \
			--nocancel \
			--menu "" \
			19 0 11 \
			${args[@]} 2> $tmpf
		[ $? -ne 0 ] && return 1
		xcountry="`cat $tmpf`"
		country="$xcountry"
		rm -f $tmpf
	else
		country=$countries
		xcountry=$countries
	fi
	return 0
}

function get_region {
	# Get list of names of time zone rule regions in the country.
	regions=$($AWK -F'\t' \
	    -v country="$country" \
	    -v TZ_COUNTRY_TABLE="$TZ_COUNTRY_TABLE" \
	    '
		BEGIN {
			cc = country
			while (getline <TZ_COUNTRY_TABLE) {
				if ($0 !~ /^#/ && country == $2) {
					cc = $1
					break
				}
			}
		}
		$1 == cc {
			if (NF > 4)
				print $5
			else
				print $3
		}
	' < $TZ_ZONE_TABLE)

	# I18n region names
	c=0
	set -A iregion
	unset args; set -a args
	for region in $regions; do
		iregion[c]=$region
		oregion[c]="$region"
		args+=("$region" "${iregion[$c]}")
		((c = c + 1))
	done

	if [[ $regions == *"$newline"* ]]; then
		# If there's one or more region, ask the user which one.
		dialog \
			--colors \
			--title "$INFO_SELECT_TZ" \
			--no-ok \
			--no-tags \
			--nocancel \
			--menu "" \
			19 0 11 \
			${args[@]} 2> $tmpf
		[ $? -ne 0 ] && return 1
		xregion="`cat $tmpf`"
		region="$xregion"
		rm -f $tmpf
	else
		region=$regions
		xregion=$regions
	fi
	return 0
}

function build_tz {
	# Determine TZ from country and region.
	TZ=$($AWK -F'\t' \
	    -v country="$country" \
	    -v region="$region" \
	    -v TZ_COUNTRY_TABLE="$TZ_COUNTRY_TABLE" \
	    '
		BEGIN {
			cc = country
			while (getline <TZ_COUNTRY_TABLE) {
				if ($0 !~ /^#/  &&  country == $2) {
					cc = $1
					break
				}
			}
		}

		$1 == cc && ((NF > 4 && $5 == region) || $3 == region) {
			# Check if tzname mapped to
			# backward compatible tzname
			if ($4 == "-")
				print $3
			else
				print $4
		}
	' < $TZ_ZONE_TABLE)

	# Make sure the corresponding zoneinfo file exists.
	TZ_for_date=$TZDIR/$TZ
	<$TZ_for_date || return 1
	# Absolute path TZ's not supported
	TZ_for_date=$TZ
	return 0
}

function check_tz {
	# Use the proposed TZ to output the current date relative to UTC.
	# Loop until they agree in seconds.
	# Give up after 8 unsuccessful tries.

	extra_info1=
	extra_info2=
	for i in 1 2 3 4 5 6 7 8; do
		TZdate=$(LANG=C TZ="$TZ_for_date" $DATE)
		UTdate=$(LANG=C TZ=UTC0 $DATE)
		TZsec=$($EXPR "$TZdate" : '.*:\([0-5][0-9]\)')
		UTsec=$($EXPR "$UTdate" : '.*:\([0-5][0-9]\)')
		case $TZsec in
		$UTsec)
			extra_info1=$($PRINTF "$INFO_EXTRA1" "$TZdate")
			extra_info2=$($PRINTF "$INFO_EXTRA2" "$UTdate")
			break
			;;
		esac
	done

	case $country+$region in
		?*+?*)	msg="$xcountry\n	$xregion\n" ;;
		?*+)	msg="	$xcountry\n" ;;
		+)	msg="	TZ='$TZ'\n"
	esac

	tzmsg=$($PRINTF "$INFO_TZ" $TZ)

	dialog \
		--colors \
		--title "$INFO_INFO" \
		--yesno "\n$msg\n
$tzmsg\n
\n
$extra_info1\n
$extra_info2\n
\n
$INFO_OK\n\Zn
" 0 0
	[ $? -ne 0 ] && return 1
	return 0
}

# Begin the main loop. We come back here if the user wants to retry.
while :; do
	continent=
	country=
	region=

	tmpf=`mktemp`

	get_continent || continue

	case $continent in
	    none)
		get_posix_tz || continue
		;;
	     UTC)
		TZ=UTC
		TZ_for_date=UTC
		;;
	    *)
		get_country || continue
		get_region || continue
		if ! build_tz; then
			d_msg $($PRINTF "$ERR_NO_SETUP\n" $0$)
			continue
		fi
		;;
	esac

	check_tz || continue
	break
done

$PRINTF "%s\n" "$TZ" > $output