#!/bin/sh

PREFIX=
. "$PREFIX/lib/libalpine.sh"


zroot=/usr/share/zoneinfo

usage() {
        cat <<__EOF__
usage: setup-timezone [-h] [-p posixtz format] [-z subfolder of $zroot]

Sets the timezone for the system.

options:
 -h  Show this help
 -p  Specify the timezone in PosixTZ format
 -z  Specify the timezone as a subfolder of $zroot
__EOF__
        exit 1
}

show_tz_list() {
	local i z= list=
	local path="$zroot/$1"
	[ -d "$path" ] || return 1

	for i in $(find $path -maxdepth 1); do
		case $i in
		*.tab|*/) continue;;
		esac
		if [ -d "$i" ]; then
			z="$z ${i##*/}/"
		else
			z="$z ${i##*/}"
		fi
	done
	( cd $path && ls --color=never -Cd $z )
}

valid_tz() {
	find $zroot -type f -a -not -name '*.tab' -a -not -name 'Factory' \
		| xargs posixtz | sort | uniq | grep -q -w "$1"
}

while getopts "hp:z:" opt; do
        case $opt in
                h) usage;;
                p) POSIXTZ="$OPTARG";;
		t) ZONEINFOFOLDER="$OPTARG";;
        esac
done

if ! apk info -q -e tzdata; then
	apk add -q tzdata && apkdel="tzdata" || exit 1
fi

zonepath=$(cat /etc/TZ 2>/dev/null)
[ -z "$zonepath" ] && zonepath="UTC"

while true; do
	if [ -n "$POSIXTZ" ]; then
		echo $POSIXTZ > /etc/TZ || rm -f /etc/TZ
		break
	fi

	if [ -n "$ZONEINFOFOLDER" ]; then
		TZ=$(posixtz "$ZONEINFOFOLDER") || echo "Failed to convert '$ZONEINFOFOLDER' to POSIX TZ"
		if [ -n "$TZ" ]; then
			echo $TZ > /etc/TZ || rm -f /etc/TZ
		fi
		break
	fi

	echo -n "Which timezone are you in? ('?' for list) [$zonepath] "
	default_read zonepath "$zonepath"
	case "$zonepath" in
	"") continue;;
	"?") show_tz_list; continue;;
	esac

	while [ -d "$zroot/$zonepath" ]; do
		zone=
		echo -n "What sub-timezone of '$zonepath' are you in? ('?' for list) "
		default_read zone
		case "$zone" in
		"?") show_tz_list "$zonepath"; continue;;
		esac
		zonepath="$zonepath/$zone"
	done

	TZ=
	if valid_tz "$zonepath"; then
		TZ="$zonepath"
	elif [ -f "$zroot/$zonepath" ]; then
		TZ=$(posixtz "$zroot/$zonepath") \
			|| echo "Failed to convert '$zroot/$zonepath' to POSIX TZ"
	fi

	if [ -n "$TZ" ]; then
		echo $TZ > /etc/TZ || rm -f /etc/TZ
		break
	fi
	echo "'$zonepath' is not a valid timezone on this system"
done

if [ -n "$apkdel" ]; then
	apk del -q $apkdel
fi