#!/usr/bin/perl

{ use 5.006; }
use warnings;
use strict;

use Time::OlsonTZ::Data qw(olson_canonical_names olson_tzfile);
use DateTime::TimeZone::Tzfile ();

my %abbr;
foreach my $zonename (keys %{olson_canonical_names()}) {
	my $zone = DateTime::TimeZone::Tzfile->new(olson_tzfile($zonename));
	# icky dependence on DT:TZ:Tzfile internals,
	# liable to break on future versions of DT:TZ:Tzfile
	foreach my $obs (@{$zone->{obs_types}}) {
		next unless ref($obs) eq "ARRAY";
		my($offs, undef, $abbr) = @$obs;
		my $arec = $abbr{$abbr} ||= { offsets=>{}, zones=>{} };
		$arec->{offsets}->{$offs} = undef;
		$arec->{zones}->{$zonename} = undef;
	}
}

foreach my $abbr (sort keys %abbr) {
	my $arec = $abbr{$abbr};
	print $abbr, ": ", join(" ", map {
		my $neg = $_ < 0;
		my $mag = abs($_);
		use integer;
		my $txt = sprintf("%s%02d:%02d:%02d", $neg ? "-" : "+",
				$mag/3600, $mag/60%60, $mag%60);
		$txt =~ s/(?::00)+\z//;
		$txt;
	} sort { $a <=> $b } keys %{$arec->{offsets}}),
	" (", join(" ", sort keys %{$arec->{zones}}), ")\n";
}

exit 0;